JP7612355B2 - Organic Compounds and Light Emitting Devices - Google Patents

Description

One aspect of the present invention relates to an organic compound, a light-emitting device, a light-emitting apparatus, an electronic device, and a lighting apparatus. However, one aspect of the present invention is not limited to the above technical fields. That is, one aspect of the present invention relates to an object, a method, a manufacturing method, or a driving method. Alternatively, one aspect of the present invention relates to a process, a machine, manufacture, or a composition of matter. Specific examples include a semiconductor device, a display device, and a liquid crystal display device.

Light-emitting devices (also called organic EL elements), which consist of an EL layer sandwiched between a pair of electrodes, have characteristics such as being thin and lightweight, having fast response to input signals, and consuming low power, so displays that use these elements are being developed at a rapid pace and are attracting a lot of attention.

In a light-emitting device, by applying a voltage between a pair of electrodes, electrons and holes injected from each electrode are recombined in the EL layer, and the light-emitting substance (organic compound) contained in the EL layer is excited, and emits light when the excited state returns to the ground state. The types of excited states include a singlet excited state (S ^* ) and a triplet excited state (T ^* ). Light emitted from the singlet excited state is called fluorescence, and light emitted from the triplet excited state is called phosphorescence. The statistical generation ratio of these in a light-emitting device is considered to be S ^* :T ^* =1:3. The emission spectrum obtained from a light-emitting substance is specific to that light-emitting substance, and light-emitting devices with various emission colors can be obtained by using different types of organic compounds as light-emitting substances.

With regard to such light-emitting devices, improvements to element structures and material development are being actively pursued in order to improve the element characteristics (see, for example, Patent Document 1).

JP 2010-182699 A

Therefore, in one embodiment of the present invention, a novel organic compound is provided. In another embodiment of the present invention, a novel organic compound having a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton is provided. In another embodiment of the present invention, a novel organic compound that can be used in a light-emitting device is provided. In another embodiment of the present invention, a novel organic compound that can be used in an EL layer of a light-emitting device is provided. In addition, a highly reliable novel light-emitting device using the novel organic compound that is one embodiment of the present invention is provided. In addition, a novel light-emitting device, a novel electronic device, or a novel lighting device is provided. Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily need to solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc.

One embodiment of the present invention is a benzofuropyridazine derivative, which is an organic compound represented by the following general formula (G1). Note that the organic compound represented by the following general formula (G1) has a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton.

In the above general formula (G1), Q represents oxygen or sulfur. A represents a group having a total of 12 to 100 carbon atoms, and has one or more of a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, a triphenylene ring, a heteroaromatic ring including a dibenzothiophene ring, a heteroaromatic ring including a dibenzofuran ring, a heteroaromatic ring including a carbazole ring, a benzimidazole ring, and a triphenylamine structure. R ¹ to R ⁵ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

Another embodiment of the present invention is a benzofuropyridazine derivative, which is an organic compound represented by the following general formula (G2). As represented by the following general formula (G2), the compound has a hole-transporting skeleton at the 3-position of the benzofuro[3,2-c]pyridazine skeleton or the benzothieno[3,2-c]pyridazine skeleton.

In the above general formula (G2), Q represents oxygen or sulfur. α represents a substituted or unsubstituted phenylene group, and n represents an integer of 0 to 4. Ht represents a _skeleton having hole transport properties. R ¹ to R ⁵ each represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

Another embodiment of the present invention is a benzofuropyridazine derivative, which is an organic compound represented by the following general formula (G3). As represented by the following general formula (G3), the compound has a hole-transporting skeleton at the 3-position of the benzofuro[3,2-c]pyridazine skeleton or the benzothieno[3,2-c]pyridazine skeleton.

In the above general formula (G3), Q represents oxygen or sulfur. _Ht represents a skeleton having hole transport properties. R ¹ to R ⁵ each represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

In each of the above structures, Ht _uni in general formulae (G2) and (G3) each independently has any one of a pyrrole ring structure, a furan ring structure, and a thiophene ring structure.

In each of the above structures, Ht _uni in the general formulas (G2) and (G3) is each independently represented by any one of the following general formulas (Ht-1) to (Ht-26).

In the above general formulae (Ht-1) to (Ht-26), Q represents oxygen or sulfur. R ² to R ⁷¹ each represent 1 to 4 substituents, and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted phenyl group. Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.

Another aspect of the present invention is an organic compound represented by either structural formula (100) or (101).

Note that another embodiment of the present invention is a light-emitting device using the organic compound that is one embodiment of the present invention described above. The present invention also includes a light-emitting device that has a guest material in addition to the organic compound.

Another embodiment of the present invention is a light-emitting device using the organic compound according to one embodiment of the present invention. The present invention also includes light-emitting devices formed by using an organic compound according to one embodiment of the present invention in an EL layer between a pair of electrodes or in a light-emitting layer included in the EL layer. In addition to the above light-emitting devices, a light-emitting device having a layer (e.g., a cap layer) having an organic compound in contact with an electrode is also included in the light-emitting device and is included in the present invention. In addition to light-emitting devices, light-emitting devices having transistors, substrates, and the like are also included in the scope of the invention. In addition to these light-emitting devices, electronic devices and lighting devices having microphones, cameras, operation buttons, external connectors, housings, covers, supports, speakers, and the like are also included in the scope of the invention.

In addition, one embodiment of the present invention includes a light-emitting device having a light-emitting device, and further includes a lighting device having a light-emitting device in its category. Therefore, in this specification, a light-emitting device refers to an image display device or a light source (including a lighting device). In addition, the light-emitting device also includes a module in which a connector such as an FPC (flexible printed circuit) or TCP (tape carrier package) is attached to a light-emitting device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (integrated circuit) is directly mounted on a light-emitting device by a COG (chip on glass) method.

In one embodiment of the present invention, a novel organic compound can be provided. In another embodiment of the present invention, a novel organic compound having a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton can be provided. In another embodiment of the present invention, a novel organic compound that can be used in a light-emitting device can be provided. In another embodiment of the present invention, a novel organic compound that can be used in an EL layer of a light-emitting device can be provided. By using the novel organic compound that is one embodiment of the present invention, a novel light-emitting device with high reliability can be provided. In addition, a novel light-emitting device, a novel electronic device, or a novel lighting device can be provided.

FIGS. 1A, 1B, 1C, 1D, and 1E are diagrams for explaining the structure of a light-emitting device. Fig. 2A is a diagram illustrating a light emitting device, Fig. 2B is a diagram illustrating a light emitting device, and Fig. 2C is a diagram illustrating a light emitting device. Fig. 3A is a top view illustrating a light emitting device, and Fig. 3B is a cross-sectional view illustrating the light emitting device. Fig. 4(A) is a diagram illustrating a mobile computer. Fig. 4(B) is a diagram illustrating a portable image playback device. Fig. 4(C) is a diagram illustrating a digital camera. Fig. 4(D) is a diagram illustrating a portable information terminal. Fig. 4(E) is a diagram illustrating a portable information terminal. Fig. 4(F) is a diagram illustrating a television device. Fig. 4(G) is a diagram illustrating a portable information terminal. Fig. 5A is a diagram illustrating an electronic device, Fig. 5B is a diagram illustrating an electronic device, and Fig. 5C is a diagram illustrating an electronic device. Fig. 6A is a diagram for explaining an automobile, and Fig. 6B is a diagram for explaining an automobile. Fig. 7A is a diagram illustrating a lighting device, and Fig. 7B is a diagram illustrating a lighting device. FIG. 8 is a ¹ H-NMR chart of the organic compound represented by the structural formula (100). FIG. 9 shows the ultraviolet-visible absorption spectrum and emission spectrum of the organic compound represented by the structural formula (100). FIG. 10 is a phosphorescence spectrum of the organic compound represented by the structural formula (100). FIG. 11 is a ¹ H-NMR chart of the organic compound represented by the structural formula (101). FIG. 12 shows the ultraviolet-visible absorption spectrum and emission spectrum of the organic compound represented by the structural formula (101).

Below, the embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes can be made to the form and details without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiment shown below.

Note that the position, size, range, etc. of each component shown in the drawings, etc. may not represent the actual position, size, range, etc., for ease of understanding. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

In addition, in this specification and the like, when explaining the configuration of the invention using drawings, symbols that refer to the same things are used commonly even between different drawings.

(Embodiment 1)
In this embodiment, an organic compound according to one embodiment of the present invention will be described. Note that the organic compound according to one embodiment of the present invention is an organic compound having a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton represented by the following general formula (G1).

In the general formula (G1), Q represents oxygen or sulfur. A represents a group having a total of 12 to 100 carbon atoms, and has one or more of a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, a triphenylene ring, a heteroaromatic ring including a dibenzothiophene ring, a heteroaromatic ring including a dibenzofuran ring, a heteroaromatic ring including a carbazole ring, a benzimidazole ring, and a triphenylamine structure. R ¹ to R ⁵ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

Another embodiment of the present invention is an organic compound represented by the following general formula (G2). Note that the organic compound of one embodiment of the present invention has a hole-transporting skeleton at the 3-position of a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton, as represented by the following general formula (G2).

In the above general formula (G2), Q represents oxygen or sulfur. α represents a substituted or unsubstituted phenylene group, and n represents an integer of 0 to 4. Ht represents a _skeleton having hole transport properties. R ¹ to R ⁵ each represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

Another embodiment of the present invention is an organic compound represented by the following general formula (G3). Note that the organic compound of one embodiment of the present invention has a hole-transporting skeleton at the 3-position of a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton, as represented by the following general formula (G3).

In the above general formula (G3), Q represents oxygen or sulfur. _Ht represents a skeleton having hole transport properties. R ¹ to R ⁵ each represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

In addition, Ht _uni in the above general formulae (G2) and (G3) each independently has any one of a pyrrole ring structure, a furan ring structure, and a thiophene ring structure.

In addition, Ht _uni in the above general formulas (G2) and (G3) is each independently represented by any one of the following general formulas (Ht-1) to (Ht-26).

In the above general formulae (Ht-1) to (Ht-26), Q represents oxygen or sulfur. R ² to R ⁷¹ each represent 1 to 4 substituents, and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted phenyl group. Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms.

In the above general formulas (G1), (G2), and (G3), when the substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, the substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, the substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or the substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms has a substituent, examples of the substituent include alkyl groups having 1 to 7 carbon atoms such as methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, isobutyl groups, sec-butyl groups, tert-butyl groups, pentyl groups, and hexyl groups; cycloalkyl groups having 5 to 7 carbon atoms such as cyclopentyl groups, cyclohexyl groups, cycloheptyl groups, and 8,9,10-trinorbornanyl groups; aryl groups having 6 to 12 carbon atoms such as phenyl groups, naphthyl groups, and biphenyl groups; and heteroaryl groups having 6 to 13 carbon atoms such as dibenzothiophenyl groups, dibenzofuranyl groups, and carbazolyl groups.

In addition, specific examples of when R ¹ to R ⁵ in the above general formulae (G1), (G2), and (G3) represent a monocyclic saturated hydrocarbon having 5 to 7 carbon atoms include a cyclopentyl group, a cyclohexyl group, a 1-methylcyclohexyl group, a cycloheptyl group, and the like.

In addition, specific examples of when ^R1 to ^R5 in the above general formulae (G1), (G2), and (G3) represent a polycyclic saturated hydrocarbon having 7 to 10 carbon atoms include a norbornyl group, an adamantyl group, a decalin group, and a tricyclodecyl group.

In addition, specific examples of the case where R ¹ to R ⁵ in the above general formulae (G1), (G2), and (G3) represent an aryl group having 6 to 13 carbon atoms include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a mesityl group, an o-biphenyl group, an m-biphenyl group, a p-biphenyl group, a 1-naphthyl group, a 2-naphthyl group, and a fluorenyl group.

Specific examples of the alkyl group having 1 to 6 carbon atoms represented by R ¹ to R ⁵ in the above general formulae (G1), (G2), and (G3) include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group.

Specific examples of the heteroaryl group having 3 to 12 carbon atoms represented by R ¹ to R ⁵ in the above general formulae (G1), (G2), and (G3) include a triazinyl group, a pyrazinyl group, a pyrimidinyl group, a pyridinyl group, a quinolinyl group, an isoquinolinyl group, a benzothienyl group, a benzofuranyl group, an indolyl group, a dibenzothienyl group, a dibenzofuranyl group, and a carbazolyl group.

Note that when R ¹ to R ⁵ in the above general formulae (G1), (G2), and (G3) each have a group represented by one of the specific examples, the organic compound that is one embodiment of the present invention has high thermal stability and physicochemical stability. In particular, when R ³ has a group represented by one of the specific examples, the thermal stability is improved due to the structure, and the LUMO is stabilized, resulting in high electron resistance. Therefore, a light-emitting device with high reliability can be obtained by manufacturing a light-emitting device using this material.

Next, specific structural formulas of the organic compounds according to one embodiment of the present invention are shown below. However, the present invention is not limited to these.

Note that the organic compounds represented by the structural formulas (100) to (121) above are examples of the organic compounds represented by the general formula (G1) above, but the organic compounds that are an embodiment of the present invention are not limited to these.

<Method for synthesizing organic compound represented by general formula (G1)>
Next, a synthesis method for an organic compound having a benzofuro[3,2-c]pyridazine skeleton or a benzothieno[3,2-c]pyridazine skeleton, which is one embodiment of the present invention and is represented by General Formula (G1) below, will be described.

In the general formula (G1), Q represents oxygen or sulfur. A represents a group having a total of 12 to 100 carbon atoms, and has one or more of a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, a triphenylene ring, a heteroaromatic ring including a dibenzothiophene ring, a heteroaromatic ring including a dibenzofuran ring, a heteroaromatic ring including a carbazole ring, a benzimidazole ring, and a triphenylamine structure. R ¹ to R ⁵ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.

The following shows a synthesis scheme (A) of the organic compound represented by the above general formula (G1). The compound represented by the general formula (G1) can be obtained by reacting a halogen compound (A1) having a benzofuropyridazine skeleton or a benzothienopyridazine skeleton with a boronic acid compound (A2) and a boronic acid compound (A3), as shown in the following synthesis scheme (A).

In the synthesis scheme (A), Q represents oxygen or sulfur. A represents a group having a total of 12 to 100 carbon atoms, and has one or more of a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, a triphenylene ring, a heteroaromatic ring including a dibenzothiophene ring, a heteroaromatic ring including a dibenzofuran ring, a heteroaromatic ring including a carbazole ring, a benzimidazole ring, and a triphenylamine structure. R ¹ to R ⁵ each independently represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms. X ¹ and X ² represent a halogen, and are preferably chlorine, bromine, or iodine. Y ¹ and Y ² each represent a boronic acid, a boronic acid ester, a cyclic triol borate salt, etc. The cyclic triol borate salt may be a potassium salt or a sodium salt in addition to a lithium salt.

When R ¹ in the halogen compound (A1) used in the above synthesis scheme (A) is hydrogen, it can be synthesized as shown in the following synthesis scheme (B). That is, intermediate (B3) can be obtained by reacting a halogenated benzofuran-3-one derivative or benzothiophen-3-one derivative (B1) with a glyoxylic acid ester (B2), and then intermediate (B4) can be obtained by reacting the intermediate (B4) with hydrazine monohydrate. By reacting this intermediate (B4) with a halogenating agent, halogen compound (A1) having a benzofuropyridazine skeleton or a benzothienopyridazine skeleton can be synthesized.

In the above synthesis scheme (B), Q represents oxygen or sulfur. ^X1 and ^X2 each represent a halogen, preferably chlorine, bromine or iodine. In the formula, ^R6 represents an alkyl group, preferably a methyl group or an ethyl group. The glyoxylic acid ester (B2) may be prepared in a solution or may be in the form of a polymer.

The halogen compound (A1) used in the synthesis scheme (A) can also be synthesized by the method shown in the synthesis scheme (C) below. That is, it can also be obtained by cyclizing the intermediate (C3) obtained by reacting the dihalogen compound (C1) with a pyridazine compound (C2) substituted with a hydroxyl group or a sulfanyl group.

In the synthesis scheme (C), Q represents oxygen or sulfur, and X ¹ to X ⁴ represent a halogen, and X ¹ to X ³ are preferably chlorine, bromine or iodine, and X ⁴ is preferably fluorine or chlorine.

Note that various types of the compounds (A1), (A2), (A3), (B1), (B2), (B3), (C1), (C2), and (C3) used in the above synthesis schemes (A) to (C) are commercially available or can be synthesized, so that many types of organic compounds represented by general formula (G1) can be synthesized. Therefore, the organic compounds of one embodiment of the present invention are abundant in variety.

The above describes an example of a method for synthesizing an organic compound according to one embodiment of the present invention, but the present invention is not limited to this, and the compound may be synthesized by any other synthesis method.

The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

(Embodiment 2)
In this embodiment mode, a light-emitting device using the organic compound shown in Embodiment Mode 1 will be described with reference to FIG.

<Basic structure of light-emitting devices>
First, a basic structure of a light-emitting device will be described. Fig. 1A shows an example of a light-emitting device having an EL layer including a light-emitting layer between a pair of electrodes. Specifically, the light-emitting device has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102.

In addition, FIG. 1B shows an example of a light-emitting device having a stacked structure (tandem structure) with multiple (two in FIG. 1B) EL layers (103a, 103b) between a pair of electrodes and a charge generating layer 104 between the EL layers. Note that the number of stacked EL layers is not limited to two, and may be three or more.

The charge generation layer 104 has the function of injecting electrons into one EL layer (103a or 103b) and injecting holes into the other EL layer (103b or 103a) when a voltage is applied between the first electrode 101 and the second electrode 102. Therefore, in FIG. 1B, when a voltage is applied to the first electrode 101 so that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 104 into the EL layer 103a and holes are injected into the EL layer 103b.

From the viewpoint of light extraction efficiency, the charge generation layer 104 is preferably transparent to visible light (specifically, the visible light transmittance of the charge generation layer 104 is 40% or more). In addition, the charge generation layer 104 functions even if it has a lower conductivity than the first electrode 101 and the second electrode 102.

In addition, Figure 1(C) shows an example of the case where the EL layer 103 shown in Figure 1(A) (the same applies when the EL layers (103a, 103b) in Figure 1(B) have a stacked structure) has a stacked structure. In this case, however, the first electrode 101 functions as an anode. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are stacked in sequence on the first electrode 101. Note that even when there are multiple EL layers as in the tandem structure shown in Figure 1(B), the EL layers are stacked in sequence from the anode side as shown in Figure 1(D). In FIG. 1D, each EL layer has a hole injection layer (111a, 111b), a hole transport layer (112a, 112b), a light emitting layer (113a, 113b), an electron transport layer (114a, 114b), and an electron injection layer (115a, 115b). In addition, when the first electrode 101 is a cathode and the second electrode 102 is an anode, the stacking order of the EL layers is reversed.

The light-emitting layer 113 included in the EL layer (103, 103a, 103b) can have a structure in which a light-emitting substance or a plurality of substances are appropriately combined, and can have a structure in which fluorescent light or phosphorescence with a desired light emission color can be obtained. The light-emitting layer 113 can also have a stacked structure with different light-emitting colors. In this case, different materials can be used as the light-emitting substance and other substances used in each stacked light-emitting layer. A structure in which different light-emitting colors can be obtained from each of the multiple EL layers (103a, 103b) shown in FIG. 1B can also be used. In this case, different materials can be used as the light-emitting substance and other substances used in each light-emitting layer. An organic compound which is one embodiment of the present invention can be used for the light-emitting layer 113.

In addition, in the light-emitting device according to one embodiment of the present invention, the light emission obtained from the EL layer (103, 103a, 103b) may be resonated between the two electrodes to enhance the light emission obtained. For example, in FIG. 1C, the first electrode 101 is a reflective electrode and the second electrode 102 is a semi-transparent and semi-reflective electrode to form a micro-optical resonator (microcavity) structure, which enhances the light emission obtained from the EL layer 103.

When the first electrode 101 of the light-emitting device is a reflective electrode having a laminated structure of a conductive material having reflectivity and a conductive material having translucency (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust the inter-electrode distance between the first electrode 101 and the second electrode 102 to be close to mλ/2 (where m is a natural number) for the wavelength λ of the light obtained from the light-emitting layer 113.

Furthermore, in order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained, and the optical distance from the second electrode 102 to the region (light-emitting region) in the light-emitting layer 113 where the desired light is obtained, to be close to (2m'+1)λ/4 (where m' is a natural number). Note that the light-emitting region here refers to the recombination region of holes and electrons in the light-emitting layer 113.

By performing such optical adjustments, it is possible to narrow the spectrum of the specific monochromatic light obtained from the light-emitting layer 113, thereby obtaining light emission with good color purity.

However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can be said to be the total thickness from the reflection area in the first electrode 101 to the reflection area in the second electrode 102, strictly speaking. However, since it is difficult to strictly determine the reflection area in the first electrode 101 or the second electrode 102, it is assumed that the above-mentioned effect can be sufficiently obtained by assuming any position of the first electrode 101 or the second electrode 102 as the reflection area. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be said to be the optical distance between the reflection area in the first electrode 101 and the light-emitting area in the light-emitting layer from which the desired light is obtained, strictly speaking. However, since it is difficult to strictly determine the reflection area in the first electrode 101 or the light-emitting area in the light-emitting layer from which the desired light is obtained, it is assumed that the above-mentioned effect can be sufficiently obtained by assuming any position of the first electrode 101 as the reflection area and any position of the light-emitting layer from which the desired light is obtained as the light-emitting area.

When the light-emitting device shown in FIG. 1(C) has a microcavity structure, it is possible to extract light of different wavelengths (monochromatic light) even if the EL layer is the same. Therefore, it is not necessary to paint different colors (e.g., RGB) to obtain different emitted colors, and high definition is possible. It is also possible to combine it with a colored layer (color filter). In addition, it is possible to increase the emission intensity of a specific wavelength in the front direction, which can reduce power consumption.

The light-emitting device shown in FIG. 1(E) is an example of a light-emitting device having a stacked structure (tandem structure) shown in FIG. 1(B), and has a structure in which three EL layers (103a, 103b, 103c) are stacked with charge generating layers (104a, 104b) sandwiched between them, as shown in the figure. The three EL layers (103a, 103b, 103c) each have a light-emitting layer (113a, 113b, 113c), and the light-emitting colors of each light-emitting layer can be freely combined. For example, the light-emitting layer 113a can be blue, the light-emitting layer 113b can be red, green, or yellow, and the light-emitting layer 113c can be blue, but it is also possible to make the light-emitting layer 113a red, the light-emitting layer 113b blue, green, or yellow, and the light-emitting layer 113c red.

In the above-described light-emitting device according to one embodiment of the present invention, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (such as a transparent electrode or a semi-transparent/semi-reflective electrode). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. When the electrode is a semi-transparent/semi-reflective electrode, the visible light reflectance of the semi-transparent/semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, it is preferable that the resistivity of these electrodes is 1×10 ⁻² Ωcm or less.

In the above-described light-emitting device according to one embodiment of the present invention, when one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the electrode having the reflectivity has a visible light reflectance of 40% to 100%, preferably 70% to 100%. In addition, the electrode preferably has a resistivity of 1× ¹⁰ Ωcm or less.

<Specific structure and manufacturing method of light-emitting device>
Next, a specific structure and a manufacturing method of the light-emitting device shown in FIG. 1, which is one embodiment of the present invention, will be described. Here, not only the light-emitting device in which the EL layer 103 has a single-layer structure as shown in FIG. 1A or FIG. 1C, but also the light-emitting device having a tandem structure as shown in FIG. 1B, FIG. 1D, and FIG. 1E will be described. When each light-emitting device shown in FIG. 1 has a microcavity structure, for example, the first electrode 101 may be formed as a reflective electrode, and the second electrode 102 may be formed as a semi-transmissive and semi-reflective electrode. In addition, a single or multiple desired electrode materials may be used to form a single layer or a stacked layer. In addition, the second electrode 102 is formed by selecting a material in the same manner as described above after forming the EL layers (103, 103b). In addition, a sputtering method or a vacuum deposition method can be used to manufacture these electrodes.

<First Electrode and Second Electrode>
As the material for forming the first electrode 101 and the second electrode 102, the following materials can be appropriately combined and used as long as the above-mentioned functions of both electrodes are satisfied. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be appropriately used. Specifically, In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, and In-W-Zn oxide can be mentioned. In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), and alloys containing these in appropriate combinations can also be used. In addition, elements belonging to Group 1 or 2 of the periodic table not exemplified above (for example, lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing appropriate combinations of these, as well as graphene, etc. can be used.

In the light-emitting device shown in FIG. 1, when the EL layer 103 has a laminated structure as shown in FIG. 1(C) and the first electrode 101 is an anode, the hole injection layer 111 and the hole transport layer 112 of the EL layer 103 are laminated in sequence on the first electrode 101 by a vacuum deposition method. Also, when a plurality of EL layers (103a, 103b) having a laminated structure are laminated with the charge generation layer 104 sandwiched therebetween as shown in FIG. 1(D) and the first electrode 101 is an anode, not only are the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a laminated in sequence on the first electrode 101 by a vacuum deposition method, but also the EL layer 103a and the charge generation layer 104 are laminated in sequence, and then the hole injection layer 111b and the hole transport layer 112b of the EL layer 103b are similarly laminated in sequence on the charge generation layer 104.

<Hole injection layer and hole transport layer>
The hole injection layers (111, 111a, 111b) are layers that inject holes from the first electrode 101, which is an anode, or the charge generation layer (104) to the EL layers (103, 103a, 103b), and contain a material with high hole injection properties.

Examples of materials with high hole injection properties include transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. In addition, phthalocyanine-based compounds such as phthalocyanine (abbreviation: H ₂ Pc) and copper phthalocyanine (abbreviation: CuPc) can be used.

In addition, the low molecular weight compounds 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N-( Aromatic amine compounds such as 4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

In addition, polymer compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD), etc., can be used. Alternatively, polymer compounds to which an acid has been added, such as poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonic acid) (abbreviation: PEDOT/PSS) and polyaniline/poly(styrenesulfonic acid) (PAni/PSS), etc. can also be used.

In addition, a composite material containing a hole transport material and an acceptor material (electron accepting material) can also be used as a material with high hole injection properties. In this case, electrons are extracted from the hole transport material by the acceptor material, generating holes in the hole injection layer (111, 111a, 111b), and the holes are injected into the light emitting layer (113, 113a, 113b) through the hole transport layer (112, 112a, 112b). The hole injection layer (111, 111a, 111b) may be formed as a single layer made of a composite material containing a hole transport material and an acceptor material (electron accepting material), or may be formed by laminating the hole transport material and the acceptor material (electron accepting material) in separate layers.

The hole transport layer (112, 112a, 112b) is a layer that transports holes injected from the first electrode 101 by the hole injection layer (111, 111a, 111b) to the light emitting layer (113, 113a, 113b). The hole transport layer (112, 112a, 112b) is a layer that contains a hole transport material. It is preferable to use a hole transport material used for the hole transport layer (112, 112a, 112b) that has a HOMO level that is the same as or close to the HOMO level of the hole injection layer (111, 111a, 111b).

As an acceptor material used in the hole injection layers (111, 111a, 111b), an oxide of a metal belonging to Groups 4 to 8 of the periodic table can be used. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among them, molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is easy to handle. In addition, organic acceptors such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives can be used. Examples of compounds having an electron-withdrawing group (halogen group or cyano group) include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ -TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCCNNQ), etc. In particular, compounds such as HAT-CN in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms are preferred because they are thermally stable. Furthermore, radialene derivatives [3] having an electron-withdrawing group (particularly a halogen group such as a fluoro group or a cyano group) are preferred because they have extremely high electron-accepting properties. Specific examples thereof include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], and the like.

As a hole-transporting material used in the hole-injection layers (111, 111a, 111b) and the hole-transporting layers (112, 112a, 112b), a substance having a hole mobility of 1×10 ⁻⁶ cm ² /Vs or more at a square root of an electric field strength [V/cm] of 600 is preferable. Note that other substances can be used as long as they have a higher hole-transporting property than electrons.

Preferred hole transport materials are those with high hole transport properties, such as π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives and furan derivatives) and aromatic amines (compounds having an aromatic amine skeleton).

The above-mentioned carbazole derivatives (compounds having a carbazole skeleton) include bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives), aromatic amines having a carbazolyl group, etc.

Specific examples of bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives) include 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(1,1'-biphenyl-4-yl)-3,3'-bi-9H-carbazole, 9,9'-bis(1,1'-biphenyl-3-yl)-3,3'-bi-9H-carbazole, 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), and 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP).

Specific examples of aromatic amines having a carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl )triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazol-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl Nyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N -phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), 4,4',4''-tris(carbazol-9-yl)triphenylamine (abbreviation: TCTA), etc.

In addition to the above, examples of carbazole derivatives include 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), etc.

Specific examples of the furan derivatives (compounds having a furan skeleton) include compounds having a thiophene skeleton such as 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II).

Specific examples of the aromatic amines include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl -3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino] Spiro-9,9'-bifluorene (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'-bifluorene (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m-M TDATA), N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc.

Polymer compounds such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl) methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can also be used as hole transport materials.

However, the hole transport material is not limited to the above, and one or a combination of various known materials can be used as the hole transport material for the hole injection layer (111, 111a, 111b) and the hole transport layer (112, 112a, 112b). Note that each of the hole transport layers (112, 112a, 112b) may be formed from multiple layers. That is, for example, a first hole transport layer and a second hole transport layer may be laminated.

In the light-emitting device shown in FIG. 1, the light-emitting layers (113, 113a) are formed by vacuum deposition on the hole transport layers (112, 112a) of the EL layers (103, 103a). In the case of the light-emitting device with a tandem structure shown in FIG. 1(D), after the EL layer 103a and the charge generation layer 104 are formed, the light-emitting layer 113b is also formed by vacuum deposition on the hole transport layer 112b of the EL layer 103b.

<Light-emitting layer>
The light-emitting layers (113, 113a, 113b, 113c) are layers containing light-emitting substances. As the light-emitting substances, substances that emit light of a color such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red are appropriately used. In addition, by using different light-emitting substances in the multiple light-emitting layers (113a, 113b, 113c), a structure that emits different light colors (for example, white light emission obtained by combining light-emitting colors that are complementary to each other) can be obtained. Furthermore, a stacked structure in which one light-emitting layer contains different light-emitting substances may be used.

The light-emitting layers (113, 113a, 113b, and 113c) may contain one or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material). As the one or more organic compounds, an organic compound according to one embodiment of the present invention, or one or both of a hole-transporting material and an electron-transporting material described in this embodiment can be used.

The light-emitting substance that can be used in the light-emitting layer (113, 113a, 113b, 113c) is not particularly limited, and can be a light-emitting substance that converts singlet excitation energy into light emission in the visible light range, or a light-emitting substance that converts triplet excitation energy (the energy difference between the ground state and the triplet excited state) into light emission in the visible light range.

Other examples of luminescent materials include the following:

Luminescent substances that convert singlet excitation energy into luminescence include fluorescent substances (fluorescent materials), such as pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. Pyrene derivatives are particularly preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophene-2-yl)-N,N '-Diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), etc.

Others include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)phenyl]- N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4' -(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra-(tert-butyl)perylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl) N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), etc. can be used.

Examples of luminescent materials that convert triplet excitation energy into luminescence include phosphorescent materials and thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

Phosphorescent materials include organometallic complexes, metal complexes (platinum complexes), rare earth metal complexes, etc. Each substance emits a different light color (light emission peak), so they can be selected and used as needed.

Examples of phosphorescent materials that exhibit blue or green light and have an emission spectrum with a peak wavelength of 450 nm or more and 570 nm or less include the following substances:

For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp) ₃ ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) ₃ ]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b) ₃ ]) ]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz) ₃ ]), and other organometallic complexes having a 4H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ₃ ]), and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) ₃ organometallic complexes having an imidazole skeleton such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi) ₃ ]) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ₃ ]); organometallic complexes having an imidazole skeleton such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C ^2' ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6) and bis[2-(4',6'-difluorophenyl)pyridinato-N,C ^2' ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C ^2' }iridium(III) picolinate (abbreviation: [Ir(CF ₃ ppy) ₂ (pic)]), and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2' ]iridium(III) acetylacetonate (abbreviation: FIr(acac)) are examples of organometallic complexes having a phenylpyridine derivative as a ligand having an electron-withdrawing group, such as iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C ^2' }iridium(III) picolinate (abbreviation: [Ir(CF 3 ppy) 2 (pic)]), and

Examples of phosphorescent materials that exhibit green or yellow color and have an emission spectrum with a peak wavelength of 495 nm or more and 590 nm or less include the following substances:

For example, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ₃ ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ₃ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ₂ (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ₂ (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) ₂ (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmpppm) ₂ (acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp) ₂ (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ₂ organometallic iridium complexes having a pyridine skeleton such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) ₂ (acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ₂ (acac)]); organometallic iridium complexes having a pyrazine skeleton such as tris(2-phenylpyridinato-N,C ^2' )iridium(III) (abbreviation: [Ir(ppy) ₃ ]) and bis(2-phenylpyridinato-N,C ^2' )iridium(III) acetylacetonate (abbreviation: [Ir(ppy) ₂ (acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq) ₂ (acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq) ₃ ]), tris(2-phenylquinolinato-N,C ^2′ )iridium(III) (abbreviation: [Ir(pq) ₃ ]), bis(2-phenylquinolinato-N,C ^2′ )iridium(III) acetylacetonate (abbreviation: [Ir(pq) ₂ organometallic iridium complexes having a pyridine skeleton such as bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy) ₂ (4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC], bis(2,4-diphenyl-1,3-oxazolato-N,C ^2' )iridium(III) acetylacetonate (abbreviation: [Ir(dpo) ₂ (acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinato-N,C ^2' }iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph) ₂ (acac)]), bis(2-phenylbenzothiazolato-N,C ^2′ )iridium(III) acetylacetonate (abbreviation: [Ir(bt) ₂ (acac)]), and other organometallic complexes, as well as rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac) ₃ (Phen)]).

Examples of phosphorescent materials that exhibit yellow or red color and have an emission spectrum with a peak wavelength of 570 nm or more and 750 nm or less include the following substances:

For example, organometallic complexes having a pyrimidine skeleton such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) ₂ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ₂ (dpm)]), (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm) ₂ (dpm)]), (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr) _{2 (} dip))]), (acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr) ₂ (dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ ² O,O')iridium(III) (abbreviation: [Ir(dmdppr-P) ₂ (dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ ² O,O')iridium(III) (abbreviation: [Ir(dmdppr-dmCP) ₂ (dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C ^2' ]iridium(III) (abbreviation: [Ir(mpq) ₂ (acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C ^2' )iridium(III) (abbreviation: [Ir(dpq) ₂ (acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ₂ and organometallic complexes having a pyrazine skeleton such as tris(1-phenylisoquinolinato-N,C ^2′ )iridium(III) (abbreviation: [Ir(piq) ₃ ]), bis(1-phenylisoquinolinato-N,C ^2′ )iridium(III) acetylacetonate (abbreviation: [Ir(piq) ₂ (acac)]), and bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC] (2,4-pentanedionato-κ ² Examples of the metal complex include organometallic complexes having a pyridine skeleton, such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: [PtOEP]), and rare earth metal complexes, such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM) ₃ (Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA) ₃ (Phen)]).

As the organic compound (host material, etc.) used in the light-emitting layer (113, 113a, 113b, 113c), one or more substances having an energy gap larger than the energy gap of the light-emitting substance (guest material) may be selected and used.

Therefore, when the light-emitting substance used in the light-emitting layer (113, 113a, 113b, 113c) is a fluorescent material, it is preferable to use an organic compound (host material) used in combination with the light-emitting substance that has a high energy level in the singlet excited state and a low energy level in the triplet excited state. As the organic compound (host material) used in combination with the light-emitting substance, in addition to the organic compound which is one embodiment of the present invention shown in embodiment 1, and the hole transporting material (described above) and the electron transporting material (described later) shown in this embodiment, a bipolar material or the like can be used. By using the organic compound which is one embodiment of the present invention shown in embodiment 1 in the light-emitting layer (particularly by using it as a host material), the initial deterioration of the light-emitting device can be suppressed and the reliability can be improved.

Although some of the examples overlap with those above, the following are specific examples of organic compounds that are suitable for combination with luminescent substances (fluorescent materials, phosphorescent materials).

When the light-emitting substance is a fluorescent material, examples of organic compounds (host materials) that can be used in combination with the light-emitting substance include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives. In addition, it is preferable to use the organic compound that is one aspect of the present invention shown in embodiment 1.

Specific examples of organic compounds (host materials) used in combination with fluorescent light-emitting substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene 2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)-biphenyl-4'-yl}-anthracene (abbreviation: FLPPA), 9,10-bis(3,5-di 9,10-di(2-naphthyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,5-tri(1-pyrenyl)benzene (abbreviation: TPB3), 5,12-diphenyltetracene, 5,12-bis(biphenyl-2-yl)tetracene, etc.

In addition, when the light-emitting substance is a phosphorescent material, an organic compound having a triplet excitation energy larger than the triplet excitation energy of the light-emitting substance may be selected as the organic compound (host material) used in combination with the light-emitting substance. In particular, the organic compound according to one embodiment of the present invention shown in embodiment 1 is suitable. Note that, when multiple organic compounds (e.g., a first host material and a second host material (or assist material), etc.) are used in combination with the light-emitting substance to form an exciplex, it is preferable to mix these multiple organic compounds with the phosphorescent material.

By adopting such a structure, light emission can be efficiently obtained using ExTET (Exciplex-Triple Energy Transfer), which is an energy transfer from an exciplex to a light-emitting material. As a combination of a plurality of organic compounds, it is preferable to use one that easily forms an exciplex, and it is particularly preferable to combine a compound that easily receives holes (hole transporting material) with a compound that easily receives electrons (electron transporting material). Note that the organic compound that is one embodiment of the present invention shown in embodiment 1 is suitable as a host material when the light-emitting material is a phosphorescent material because the triplet excited state is stable. When forming the above-mentioned exciplex, it is suitable as an electron transporting material. In addition, it is particularly suitable when used in combination with a phosphorescent material that exhibits green light emission due to its triplet excited energy level.

In addition, examples of organic compounds (host materials, assist materials) that can be used in combination with the light-emitting substance when the light-emitting substance is a phosphorescent material include aromatic amines, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, zinc and aluminum metal complexes, oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, and phenanthroline derivatives.

Note that among the above, specific examples of aromatic amines (compounds having an aromatic amine skeleton), which are organic compounds with high hole transport properties, include the same as the specific examples of the hole transport materials shown above.

Specific examples of carbazole derivatives, which are organic compounds with high hole transport properties, include the same as the specific examples of hole transport materials listed above.

Specific examples of dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole transport properties, include 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 1,3,5-tri(dibenzothiophene-4-yl)-benzene ( Abbreviated name: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated name: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated name: DBTFLP-IV), 4-[3-(triphenylen-2-yl)phenyl]dibenzothiophene (abbreviated name: mDBTPTp-II), etc.

Specific examples of zinc- or aluminum-based metal complexes, which are organic compounds with high electron transport properties, include metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq ₃ ), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq ₂ ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq).

In addition, metal complexes having oxazole-based or thiazole-based ligands such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) can also be used.

Specific examples of organic compounds with high electron transport properties, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, and phenanthroline derivatives, include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole- 2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-bis(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole -9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II).

Specific examples of heterocyclic compounds having a diazine skeleton, heterocyclic compounds having a triazine skeleton, and heterocyclic compounds having a pyridine skeleton, which are organic compounds with high electron transport properties, include 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl- 9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and the like. In particular, the organic compound which is one embodiment of the present invention shown in embodiment 1 can also be used.

In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used as organic compounds with high electron transport properties.

When multiple organic compounds are used in the light-emitting layer (113, 113a, 113b, 113c), two types of compounds (a first compound and a second compound) that form an exciplex may be mixed with an organometallic complex. In this case, various organic compounds can be used in appropriate combination, but in order to efficiently form an exciplex, it is particularly preferable to combine a compound that easily receives holes (a hole transporting material) with a compound that easily receives electrons (an electron transporting material). Specific examples of the hole transporting material and the electron transporting material can be the materials shown in this embodiment. With this configuration, high efficiency, low voltage, and long life can be achieved at the same time.

The TADF material is a material that can upconvert a triplet excited state to a singlet excited state by a small amount of thermal energy (reverse intersystem crossing), and efficiently emits light (fluorescence) from the singlet excited state. In addition, conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited level and the singlet excited level of 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. In addition, the delayed fluorescence in the TADF material refers to light emission that has a spectrum similar to that of normal fluorescence, but has a remarkably long life. The life is 10 ⁻⁶ seconds or more, preferably 10 ⁻³ seconds or more.

Examples of TADF materials include fullerene and its derivatives, acridine derivatives such as proflavine, eosin, etc. Also included are metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF ₂ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF ₂ (OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF ₂ (Etio I)), octaethylporphyrin-platinum chloride complex (abbreviation: PtCl ₂ OEP), and the like.

Others include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), and 3-[4-(5-phenyl-5,10-dihydrophenanthracene) Examples of heterocyclic compounds having a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring include bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), and the like. In addition, a substance in which a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded is particularly preferable because the donor property of the π-electron rich heteroaromatic ring and the acceptor property of the π-electron deficient heteroaromatic ring are both strong, and the energy difference between the singlet excited state and the triplet excited state is small.

When using a TADF material, it can be used in combination with other organic compounds. In particular, it is preferable to use the organic compound which can be combined with the above-mentioned host material, hole transport material, and electron transport material and which is one embodiment of the present invention shown in embodiment 1 as a host material for the TADF material.

The above materials can be used to form the light-emitting layers (113, 113a, 113b) by combining them with low-molecular-weight materials or polymeric materials. For film formation, known methods (such as vapor deposition, coating, and printing) can be used as appropriate.

In the light-emitting device shown in FIG. 1, an electron transport layer (114, 114a) is formed on the light-emitting layer (113, 113a) of the EL layer (103, 103a). In the case of a light-emitting device having a tandem structure shown in FIG. 1(D), after the EL layer 103a and the charge generation layer 104 are formed, an electron transport layer 114b is also formed on the light-emitting layer 113b of the EL layer 103b.

<Electron Transport Layer>
The electron transport layer (114, 114a, 114b) is a layer that transports electrons injected from the second electrode 102 to the light-emitting layer (113, 113a, 113b) by the electron injection layer (115, 115a, 115b). Note that the electron transport layer (114, 114a, 114b) is a layer containing an electron transport material. The electron transport material used for the electron transport layer (114, 114a, 114b) is preferably a substance having an electron mobility of 1×10 ⁻⁶ cm ² /Vs or more at a square root of an electric field strength [V/cm] of 600. Note that any substance other than these can be used as long as it has a higher electron transport property than a hole transport property. In addition, the organic compound which is one embodiment of the present invention described in Embodiment 1 has a high electron transport property, and therefore can also be used as an electron transport layer.

As electron transport materials, materials with high electron transport properties such as metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, etc., as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having quinoline ligands, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other π-electron deficient heteroaromatic compounds including nitrogen-containing heteroaromatic compounds can be used.

Specific examples of the electron transporting material include metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq ₃ ), tris(4-methyl-8-quinolinolato)aluminum (abbreviation: Almq ₃ ), bis(10-hydroxybenzo[h]quinolinato)beryllium (abbreviation: BeBq ₂ ), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), and bis(8-quinolinolato)zinc(II) (abbreviation: Znq); and metal complexes having an oxazole skeleton or a thiazole skeleton, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

In addition to metal complexes, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: oxadiazole derivatives such as 3-(4'-tert-butylphenyl)-4-phenyl-5-(4''-biphenyl)-1,2,4-triazole (abbreviation: TAZ) and 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviation: p-EtTAZ); imidazole derivatives (including benzimidazole derivatives) such as 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II) and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs ), phenanthroline derivatives such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), and 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline quinoxaline derivatives such as sarin (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), or dibenzoquinoxaline derivatives, 3,5-bis[3- pyridine derivatives such as 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDB TP2Pm-II), pyrimidine derivatives such as 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), and triazine derivatives such as 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn). In particular, the organic compound which is one embodiment of the present invention shown in embodiment 1 can also be used.

In addition, polymer compounds such as poly(2,5-pyridinediyl) (abbreviation: PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviation: PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviation: PF-BPy) can also be used.

In addition, the electron transport layer (114, 114a, 114b) may be not only a single layer, but also a laminate structure of two or more layers made of the above-mentioned materials.

Next, in the light-emitting device shown in FIG. 1(D), an electron injection layer 115a is formed on the electron transport layer 114a of the EL layer 103a by vacuum deposition. After that, the EL layer 103a and the charge generation layer 104 are formed, and after the electron transport layer 114b of the EL layer 103b is formed, an electron injection layer 115b is formed on top by vacuum deposition.

<Electron injection layer>
The electron injection layer (115, 115a, 115b) is a layer containing a substance with high electron injection properties. For the electron injection layer (115, 115a, 115b), an alkali metal, an alkaline earth metal, or a compound thereof, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ₂ ), or lithium oxide (LiO _x ), can be used. In addition, a rare earth metal compound, such as erbium fluoride (ErF ₃ ), can be used. In addition, an electride can be used for the electron injection layer (115, 115a, 115b). For example, an electride can be a substance in which electrons are added to a mixed oxide of calcium and aluminum at a high concentration. In addition, the substance constituting the above-mentioned electron transport layer (114, 114a, 114b) can also be used.

In addition, a composite material obtained by mixing an organic compound and an electron donor (donor) may be used for the electron injection layer (115, 115a, 115b). Such a composite material has excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material that is excellent in transporting the generated electrons, and specifically, for example, the electron transport material (metal complex, heteroaromatic compound, etc.) used in the above-mentioned electron transport layer (114, 114a, 114b) can be used. As the electron donor, any substance that exhibits electron donating properties to the organic compound may be used. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, and examples of such materials include lithium, cesium, magnesium, calcium, erbium, and ytterbium. In addition, alkali metal oxides and alkaline earth metal oxides are preferred, and examples of such materials include lithium oxide, calcium oxide, and barium oxide. In addition, a Lewis base such as magnesium oxide can also be used. Organic compounds such as tetrathiafulvalene (TTF) can also be used.

In the light-emitting device shown in FIG. 1D, when the light obtained from the light-emitting layer 113b is amplified, it is preferable to form the optical distance between the second electrode 102 and the light-emitting layer 113b so that it is less than 1/4 of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, it can be adjusted by changing the film thickness of the electron transport layer 114b or the electron injection layer 115b.

<Charge Generation Layer>
In the light-emitting device shown in FIG. 1D, the charge generation layer 104 has a function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layer 104 may be a structure in which an electron acceptor is added to a hole transporting material, or a structure in which an electron donor is added to an electron transporting material. In addition, both of these structures may be stacked. By forming the charge generation layer 104 using the above-mentioned material, it is possible to suppress an increase in driving voltage when EL layers are stacked.

In the case where an electron acceptor is added to the hole-transporting material in the charge generation layer 104, the material shown in this embodiment mode can be used as the hole-transporting material. Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F ₄ -TCNQ) and chloranil. Examples of the oxide of a metal belonging to Groups 4 to 8 of the periodic table include oxides of metals. Specific examples of the oxide include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide.

When the charge generation layer 104 has a structure in which an electron donor is added to an electron transport material, the material shown in this embodiment can be used as the electron transport material. In addition, as the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, or a metal belonging to Groups 2 and 13 of the periodic table, and an oxide or carbonate thereof can be used. Specifically, it is preferable to use lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or the like. In addition, an organic compound such as tetrathianaphthacene may be used as the electron donor.

The EL layer 103c in FIG. 1E may have the same structure as the EL layers (103, 103a, and 103b) described above. The charge generation layers 104a and 104b may have the same structure as the charge generation layer 104 described above.

<Substrate>
The light-emitting device shown in this embodiment mode can be formed on various substrates. Note that the type of substrate is not limited to a specific one. Examples of the substrate include a semiconductor substrate (e.g., a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, a tungsten substrate, a substrate having tungsten foil, a flexible substrate, a laminated film, a paper containing a fibrous material, or a base film.

Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, and soda lime glass. Examples of flexible substrates, laminated films, and base films include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aramid resin, epoxy resin, inorganic vapor deposition film, and paper.

Note that the light-emitting device shown in this embodiment can be manufactured using a vacuum process such as a vapor deposition method, or a solution process such as a spin coating method or an inkjet method. When a vapor deposition method is used, a physical vapor deposition method (PVD method) such as a sputtering method, an ion plating method, an ion beam deposition method, a molecular beam deposition method, or a vacuum deposition method, or a chemical vapor deposition method (CVD method), etc. can be used. In particular, the functional layers (hole injection layer (111, 111a, 111b), hole transport layer (112, 112a, 112b), light emitting layer (113, 113a, 113b, 113c), electron transport layer (114, 114a, 114b), electron injection layer (115, 115a, 115b), and charge generation layer (104, 104a, 104b)) included in the EL layer of the light emitting device can be formed by a method such as a deposition method (vacuum deposition method, etc.), a coating method (dip coating method, die coating method, bar coating method, spin coating method, spray coating method, etc.), a printing method (inkjet method, screen (screen printing) method, offset (lithographic printing) method, flexo (relief printing) method, gravure method, microcontact method, nanoimprint method, etc.).

In addition, the functional layers (hole injection layer (111, 111a, 111b), hole transport layer (112, 112a, 112b), light emitting layer (113, 113a, 113b, 113c), electron transport layer (114, 114a, 114b), electron injection layer (115, 115a, 115b) and charge generation layer (104, 104a, 104b)) constituting the EL layer (103, 103a, 103b) of the light emitting device shown in this embodiment are not limited to the above-mentioned materials, and other materials can be used in combination as long as they can fulfill the functions of each layer. As an example, a polymer compound (oligomer, dendrimer, polymer, etc.), a medium molecular compound (a compound in the intermediate range between a low molecular weight and a polymer: molecular weight 400 to 4000), an inorganic compound (quantum dot material, etc.), etc. can be used. As quantum dot materials, colloidal quantum dot materials, alloy quantum dot materials, core-shell quantum dot materials, core quantum dot materials, etc. can be used.

The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

(Embodiment 3)
In this embodiment, a light-emitting device according to one embodiment of the present invention will be described. The light-emitting device shown in FIG. 2A is an active matrix type light-emitting device in which a transistor (FET) 202 and light-emitting devices (203R, 203G, 203B, 203W) on a first substrate 201 are electrically connected, and the light-emitting devices (203R, 203G, 203B, 203W) have a common EL layer 204 and have a microcavity structure in which the optical distance between the electrodes of each light-emitting device is adjusted according to the light-emitting color of each light-emitting device. In addition, the light-emitting device is a top-emission type light-emitting device in which light emitted from the EL layer 204 is emitted through color filters (206R, 206G, 206B) formed on a second substrate 205.

In the light-emitting device shown in FIG. 2A, the first electrode 207 is formed to function as a reflective electrode. The second electrode 208 is formed to function as a semi-transmissive and semi-reflective electrode. Note that the electrode materials for forming the first electrode 207 and the second electrode 208 may be appropriately selected by referring to the descriptions of other embodiments.

In addition, in FIG. 2(A), for example, when the light-emitting device 203R is a red light-emitting device, the light-emitting device 203G is a green light-emitting device, the light-emitting device 203B is a blue light-emitting device, and the light-emitting device 203W is a white light-emitting device, as shown in FIG. 2(B), the light-emitting device 203R is adjusted so that the optical distance between the first electrode 207 and the second electrode 208 is 200R, the light-emitting device 203G is adjusted so that the optical distance between the first electrode 207 and the second electrode 208 is 200G, and the light-emitting device 203B is adjusted so that the optical distance between the first electrode 207 and the second electrode 208 is 200B. Note that, as shown in FIG. 2(B), optical adjustment can be performed by stacking the conductive layer 210R on the first electrode 207 in the light-emitting device 203R and stacking the conductive layer 210G on the first electrode 207 in the light-emitting device 203G.

Color filters (206R, 206G, 206B) are formed on the second substrate 205. The color filters are filters that pass a specific wavelength range of visible light and block a specific wavelength range. Therefore, as shown in FIG. 2A, by providing a color filter 206R that passes only the red wavelength range at a position overlapping with the light-emitting device 203R, red light can be emitted from the light-emitting device 203R. By providing a color filter 206G that passes only the green wavelength range at a position overlapping with the light-emitting device 203G, green light can be emitted from the light-emitting device 203G. By providing a color filter 206B that passes only the blue wavelength range at a position overlapping with the light-emitting device 203B, blue light can be emitted from the light-emitting device 203B. However, the light-emitting device 203W can emit white light without providing a color filter. A black layer (black matrix) 209 may be provided at the end of one type of color filter. Furthermore, the color filters (206R, 206G, 206B) and the black layer 209 may be covered with an overcoat layer made of a transparent material.

2A shows a light-emitting device having a structure (top emission type) in which light is extracted on the second substrate 205 side, but as shown in FIG. 2C, a light-emitting device having a structure (bottom emission type) in which light is extracted on the first substrate 201 side on which the FET 202 is formed may be used. In the case of a bottom emission type light-emitting device, the first electrode 207 is formed to function as a semi-transmissive/semi-reflective electrode, and the second electrode 208 is formed to function as a reflective electrode. In addition, the first substrate 201 is at least a light-transmitting substrate. In addition, the color filters (206R', 206G', 206B') may be provided on the first substrate 201 side rather than the light-emitting devices (203R, 203G, 203B) as shown in FIG. 2C.

In addition, in FIG. 2A, the light-emitting device is shown as a red light-emitting device, a green light-emitting device, a blue light-emitting device, and a white light-emitting device, but the light-emitting device according to one embodiment of the present invention is not limited to this configuration, and may have a yellow light-emitting device or an orange light-emitting device. Note that the materials used in the EL layer (light-emitting layer, hole injection layer, hole transport layer, electron transport layer, electron injection layer, charge generation layer, etc.) for producing these light-emitting devices may be appropriately selected by referring to the descriptions in other embodiments. Note that in this case, it is also necessary to appropriately select a color filter according to the light-emitting color of the light-emitting device.

By configuring as described above, it is possible to obtain a light emitting device equipped with a light emitting device that emits multiple light colors.

Note that the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

(Embodiment 4)
In this embodiment, a light-emitting device which is one embodiment of the present invention will be described.

By applying the element configuration of the light-emitting device which is one aspect of the present invention, an active matrix light-emitting device or a passive matrix light-emitting device can be manufactured. Note that an active matrix light-emitting device has a configuration in which a light-emitting device and a transistor (FET) are combined. Therefore, both a passive matrix light-emitting device and an active matrix light-emitting device are included in one aspect of the present invention. Note that the light-emitting device described in the other embodiments can be applied to the light-emitting device shown in this embodiment.

In this embodiment, an active matrix light-emitting device is described with reference to FIG.

Note that FIG. 3(A) is a top view showing a light-emitting device, and FIG. 3(B) is a cross-sectional view taken along dashed line A-A' in FIG. 3(A). The active matrix light-emitting device has a pixel portion 302, a driver circuit portion (source line driver circuit) 303, and a driver circuit portion (gate line driver circuit) (304a, 304b) provided on a first substrate 301. The pixel portion 302 and the driver circuit portion (303, 304a, 304b) are sealed between the first substrate 301 and the second substrate 306 by a sealant 305.

In addition, a wiring 307 is provided on the first substrate 301. The wiring 307 is electrically connected to an FPC 308, which is an external input terminal. The FPC 308 transmits signals (e.g., video signals, clock signals, start signals, reset signals, etc.) and potentials from the outside to the driver circuit units (303, 304a, 304b). A printed wiring board (PWB) may be attached to the FPC 308. The state in which the FPC or PWB is attached is included in the light-emitting device.

Next, the cross-sectional structure is shown in Figure 3 (B).

The pixel section 302 is formed by a plurality of pixels each having a FET (switching FET) 311, a FET (current control FET) 312, and a first electrode 313 electrically connected to the FET 312. Note that the number of FETs each pixel has is not particularly limited, and can be appropriately provided as necessary.

FETs 309, 310, 311, and 312 are not particularly limited, and can be, for example, staggered or inverted staggered transistors. They may also have a transistor structure such as a top gate or bottom gate type.

The crystallinity of the semiconductor that can be used for these FETs 309, 310, 311, and 312 is not particularly limited, and any of an amorphous semiconductor and a semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in a part) may be used. The use of a semiconductor having crystallinity is preferable because it can suppress the deterioration of the transistor characteristics.

Furthermore, as these semiconductors, for example, Group 14 elements, compound semiconductors, oxide semiconductors, organic semiconductors, etc. can be used. Representative examples include semiconductors containing silicon, semiconductors containing gallium arsenide, and oxide semiconductors containing indium.

The driving circuit unit 303 has a FET 309 and a FET 310. The driving circuit unit 303 may be formed of a circuit including transistors of a single polarity (either N-type or P-type only), or may be formed of a CMOS circuit including N-type transistors and P-type transistors. It may also be configured to have an external driving circuit.

The end of the first electrode 313 is covered with an insulator 314. Note that the insulator 314 can be made of an organic compound such as a negative photosensitive resin or a positive photosensitive resin (acrylic resin), or an inorganic compound such as silicon oxide, silicon oxynitride, or silicon nitride. The upper or lower end of the insulator 314 preferably has a surface with curvature. This can improve the coverage of the film formed on the upper layer of the insulator 314.

An EL layer 315 and a second electrode 316 are stacked on the first electrode 313. The EL layer 315 has a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a charge generation layer, etc.

The structure and materials described in the other embodiments can be applied to the structure of the light-emitting device 317 shown in this embodiment. Although not shown here, the second electrode 316 is electrically connected to the FPC 308, which is an external input terminal.

In addition, although only one light-emitting device 317 is shown in the cross-sectional view shown in FIG. 3B, a plurality of light-emitting devices are arranged in a matrix in the pixel portion 302. In the pixel portion 302, light-emitting devices that can emit three types of light (R, G, B) can be selectively formed to form a light-emitting device capable of full-color display. In addition to the light-emitting devices that can emit three types of light (R, G, B), light-emitting devices that can emit, for example, white (W), yellow (Y), magenta (M), cyan (C), etc., may be formed. For example, by adding the above-mentioned light-emitting devices that can emit several types of light to the light-emitting devices that can emit three types of light (R, G, B), effects such as improved color purity and reduced power consumption can be obtained. In addition, a light-emitting device that can display full color may be formed by combining with a color filter. Note that the types of color filters that can be used are red (R), green (G), blue (B), cyan (C), magenta (M), yellow (Y), etc.

The FETs (309, 310, 311, 312) and the light-emitting device 317 on the first substrate 301 are provided in a region 318 surrounded by the first substrate 301, the second substrate 306, and the sealant 305 by bonding the second substrate 306 and the first substrate 301 with the sealant 305. Note that the region 318 may be filled with an inert gas (such as nitrogen or argon) or an organic substance (including the sealant 305).

The sealing material 305 can be made of epoxy resin or glass frit. It is preferable to use a material that is as impermeable to moisture and oxygen as possible for the sealing material 305. The second substrate 306 can be made of the same material as the first substrate 301. Therefore, it is possible to use various substrates as described in other embodiments as appropriate. In addition to glass substrates and quartz substrates, plastic substrates made of FRP (Fiber-Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like can be used as the substrate. When glass frit is used as the sealing material, it is preferable that the first substrate 301 and the second substrate 306 are glass substrates from the viewpoint of adhesiveness.

In this way, an active matrix type light emitting device can be obtained.

When forming an active matrix type light emitting device on a flexible substrate, the FET and the light emitting device may be formed directly on the flexible substrate, or the FET and the light emitting device may be formed on a separate substrate having a peeling layer, and then the FET and the light emitting device may be peeled off at the peeling layer by applying heat, force, laser irradiation, etc., and then transferred to the flexible substrate. As the peeling layer, for example, a laminate of inorganic films of a tungsten film and a silicon oxide film, or an organic resin film such as polyimide, etc. may be used. In addition to substrates on which transistors can be formed, flexible substrates include paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates, cloth substrates (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester) or regenerated fibers (acetate, cupra, rayon, regenerated polyester), etc.), leather substrates, or rubber substrates. By using these substrates, it is possible to achieve excellent durability and heat resistance, as well as light weight and thinness.

Note that the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

(Embodiment 5)
In this embodiment, examples of various electronic devices and automobiles completed by applying a light-emitting device according to one embodiment of the present invention and a light-emitting device having a light-emitting device according to one embodiment of the present invention will be described. Note that the light-emitting device can be applied mainly to a display portion in the electronic devices described in this embodiment.

The electronic devices shown in Figures 4(A) to 4(E) may have a housing 7000, a display unit 7001, a speaker 7003, an LED lamp 7004, operation keys 7005 (including a power switch or an operation switch), a connection terminal 7006, a sensor 7007 (including a function for measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared light), a microphone 7008, etc.

Figure 4(A) is a mobile computer, which may have a switch 7009, an infrared port 7010, etc. in addition to what has been described above.

Figure 4 (B) shows a portable image playback device (e.g., a DVD playback device) equipped with a recording medium, which, in addition to the above, can also have a second display unit 7002, a recording medium reading unit 7011, etc.

Figure 4 (C) shows a digital camera with a television receiving function, which, in addition to the above, can also have an antenna 7014, a shutter button 7015, an image receiving unit 7016, etc.

Figure 4 (D) shows a mobile information terminal. The mobile information terminal has a function of displaying information on three or more sides of the display unit 7001. Here, an example is shown in which information 7052, information 7053, and information 7054 are displayed on different sides. For example, a user can check information 7053 displayed in a position that can be observed from above the mobile information terminal while the mobile information terminal is stored in a breast pocket of clothes. The user can check the display without taking the mobile information terminal out of the pocket and decide, for example, whether to answer a call.

Figure 4 (E) shows a mobile information terminal (including a smartphone), which can have a display portion 7001, operation keys 7005, and the like in a housing 7000. Note that the mobile information terminal may also be provided with a speaker 9003, a connection terminal 7006, a sensor 9007, and the like. The mobile information terminal can also display text and image information on multiple surfaces. Here, an example is shown in which three icons 7050 are displayed. Information 7051 shown in a dashed rectangle can also be displayed on another surface of the display portion 7001. Examples of the information 7051 include notifications of incoming e-mail, SNS, telephone calls, etc., titles of e-mails and SNS, sender names, date and time, remaining battery level, antenna reception strength, and the like. Alternatively, an icon 7050 or the like may be displayed at the position where the information 7051 is displayed.

Figure 4 (F) shows a large television device (also called a television or television receiver), which can have a housing 7000, a display portion 7001, and the like. Here, the housing 7000 is supported by a stand 7018. The television device can be operated using a separate remote control 7111, or the like. Note that the display portion 7001 may be provided with a touch sensor, and the display portion 7001 may be operated by touching it with a finger or the like. The remote control 7111 may have a display portion that displays information output from the remote control 7111. The channel and volume can be operated using an operation key or touch panel provided on the remote control 7111, and an image displayed on the display portion 7001 can be operated.

The electronic devices shown in Figures 4(A) to 4(F) can have various functions. For example, they can have a function of displaying various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function of displaying a calendar, date or time, a function of controlling processing by various software (programs), a wireless communication function, a function of connecting to various computer networks using the wireless communication function, a function of transmitting or receiving various data using the wireless communication function, a function of reading out a program or data recorded on a recording medium and displaying it on the display unit, etc. Furthermore, in an electronic device having multiple display units, they can have a function of displaying image information mainly on one display unit and text information mainly on another display unit, or a function of displaying a stereoscopic image by displaying an image taking into account parallax on multiple display units, etc. Furthermore, in an electronic device having an image receiving unit, they can have a function of taking a still image, a function of taking a video, a function of automatically or manually correcting the taken image, a function of saving the taken image on a recording medium (external or built into the camera), a function of displaying the taken image on the display unit, etc. Note that the functions that the electronic devices shown in Figures 4(A) to 4(F) can have are not limited to these, and can have a variety of functions.

Figure 4 (G) shows a wristwatch-type mobile information terminal, which can be used as, for example, a smart watch. This wristwatch-type mobile information terminal has a housing 7000, a display unit 7001, operation buttons 7022 and 7023, a connection terminal 7024, a band 7025, a microphone 7026, a sensor 7029, a speaker 7030, and the like. The display surface of the display unit 7001 is curved, and display can be performed along the curved display surface. This mobile information terminal is also capable of hands-free conversation through mutual communication with, for example, a headset capable of wireless communication. Note that the connection terminal 7024 can be used to transmit data to and from other information terminals and to charge the terminal. Charging can also be performed by wireless power supply.

The display unit 7001 mounted on the housing 7000, which also serves as a bezel, has a non-rectangular display area. The display unit 7001 can display an icon 7027 representing the time, other icons 7028, and the like. The display unit 7001 may also be a touch panel (input/output device) equipped with a touch sensor (input device).

The smartwatch shown in FIG. 4(G) can have various functions. For example, it can have a function to display various information (still images, videos, text images, etc.) on the display unit, a touch panel function, a function to display a calendar, date or time, etc., a function to control processing by various software (programs), a wireless communication function, a function to connect to various computer networks using the wireless communication function, a function to transmit or receive various data using the wireless communication function, a function to read out a program or data recorded on a recording medium and display it on the display unit, etc.

Furthermore, the housing 7000 may have a speaker, a sensor (including a function to measure force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone, etc.

Note that the light-emitting device which is one embodiment of the present invention and the display device having the light-emitting device which is one embodiment of the present invention can be used in each display portion of the electronic devices described in this embodiment, and the electronic devices can have a long lifetime.

Furthermore, as an electronic device to which a light-emitting device is applied, there is a foldable portable information terminal as shown in Figs. 5A to 5C. Fig. 5A shows the portable information terminal 9310 in an unfolded state. Fig. 5B shows the portable information terminal 9310 in a state in the process of changing from one of the unfolded state and the folded state to the other. Fig. 5C shows the portable information terminal 9310 in a folded state. The portable information terminal 9310 has excellent portability in a folded state, and has excellent display visibility due to a seamless wide display area in an unfolded state.

The display portion 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display portion 9311 may be a touch panel (input/output device) equipped with a touch sensor (input device). The display portion 9311 can be reversibly transformed from an unfolded state to a folded state of the portable information terminal 9310 by bending the two housings 9315 via the hinges 9313. Note that the light-emitting device of one embodiment of the present invention can be used for the display portion 9311. In addition, an electronic device with a long life can be realized. The display region 9312 in the display portion 9311 is a display region located on the side of the portable information terminal 9310 in the folded state. The display region 9312 can display information icons, frequently used apps, shortcuts to programs, and the like, and thus allows the user to smoothly check information and start apps, etc.

An automobile to which the light-emitting device is applied is shown in Fig. 6(A) and (B). That is, the light-emitting device can be provided integrally with the automobile. Specifically, the light-emitting device can be applied to the exterior light 5101 (including the rear of the vehicle body), the wheel 5102 of the tire, and a part or the whole of the door 5103 of the automobile shown in Fig. 6(A). The light-emitting device can also be applied to the display part 5104, the steering wheel 5105, the shift lever 5106, the seat 5107, the inner rear-view mirror 5108, and the like inside the automobile shown in Fig. 6(B). In addition, the light-emitting device may be applied to a part of a glass window.

In the above manner, an electronic device or an automobile to which the light-emitting device or the display device according to one embodiment of the present invention is applied can be obtained. In this case, an electronic device with a long life can be realized. Note that the electronic devices and automobiles to which the present invention can be applied are not limited to those described in this embodiment, and can be applied in any field.

Note that the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

(Embodiment 6)
In this embodiment, a structure of a lighting device manufactured using a light-emitting device which is one embodiment of the present invention or a light-emitting device which is a part of the light-emitting device will be described with reference to FIGS.

Figures 7(A) and (B) show examples of cross-sectional views of lighting devices. Note that Figure 7(A) shows a bottom-emission type lighting device that extracts light on the substrate side, and Figure 7(B) shows a top-emission type lighting device that extracts light on the sealing substrate side.

The lighting device 4000 shown in FIG. 7A has a light-emitting device 4002 on a substrate 4001. The lighting device 4000 also has a substrate 4003 having projections and recesses on the outer side of the substrate 4001. The light-emitting device 4002 has a first electrode 4004, an EL layer 4005, and a second electrode 4006.

The first electrode 4004 is electrically connected to the electrode 4007, and the second electrode 4006 is electrically connected to the electrode 4008. In addition, an auxiliary wiring 4009 electrically connected to the first electrode 4004 may be provided. Note that an insulating layer 4010 is formed on the auxiliary wiring 4009.

The substrate 4001 and the sealing substrate 4011 are bonded with a sealant 4012. A desiccant 4013 is preferably provided between the sealing substrate 4011 and the light-emitting device 4002. Note that the substrate 4003 has projections and recesses as shown in FIG. 7A, which can improve the extraction efficiency of light generated in the light-emitting device 4002.

The lighting device 4200 in FIG. 7B has a light-emitting device 4202 on a substrate 4201. The light-emitting device 4202 has a first electrode 4204, an EL layer 4205, and a second electrode 4206.

The first electrode 4204 is electrically connected to the electrode 4207, and the second electrode 4206 is electrically connected to the electrode 4208. An auxiliary wiring 4209 electrically connected to the second electrode 4206 may be provided. An insulating layer 4210 may be provided under the auxiliary wiring 4209.

The substrate 4201 and the sealing substrate 4211 having projections and recesses are bonded with a sealant 4212. A barrier film 4213 and a planarization film 4214 may be provided between the sealing substrate 4211 and the light-emitting device 4202. Note that since the sealing substrate 4211 has projections and recesses as shown in FIG. 7B, the extraction efficiency of light generated in the light-emitting device 4202 can be improved.

An example of the application of these lighting devices is a ceiling light for indoor lighting. Ceiling lights come in a direct ceiling type and a ceiling recessed type. Such lighting devices are constructed by combining a light-emitting device with a housing and a cover.

Other applications include footlights that shine light onto the floor surface to increase safety at the feet. Footlights are effective for use in bedrooms, stairs, and corridors, for example. In such cases, the size and shape can be changed as appropriate depending on the size and structure of the room. It is also possible to create a stationary lighting device consisting of a combination of a light-emitting device and a support stand.

It can also be used as a sheet-type lighting device (sheet lighting). Sheet lighting is attached to a wall surface and can be used for a wide range of purposes without taking up much space. It can also be easily made larger. It can also be used on curved walls or housings.

In addition to the above, a light-emitting device according to one embodiment of the present invention, or a light-emitting device that is a part of the light-emitting device, can be applied to a part of furniture installed in a room to provide a lighting device that functions as furniture.

As described above, various lighting devices using light-emitting devices can be obtained. These lighting devices are considered to be included in one aspect of the present invention.

Furthermore, the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

Synthesis Example 1
Example 1 This example describes a synthesis method for 3-[3-(dibenzothiophen-4-yl)phenyl]-7-phenyl[1]benzofuro[3,2-c]pyridazine (abbreviation: 7Ph-3mDBtPBfpd), an organic compound according to one embodiment of the present invention, which is represented by the structural formula (100) in Embodiment 1. The structure of 7Ph-3mDBtPBfpd is shown below.

<Step 1: Synthesis of ethyl 2-(6-chloro-3-oxo-1-benzofuran-2-yl)-2-hydroxyacetate>
First, 24 mL of ethyl glyoxylate (polymer type) (47% toluene solution) was added to a three-neck flask, the flask was replaced with nitrogen, and 230 mL of toluene was added. In an ice bath, 0.54 g (4.7 mmol) of trifluoroacetic acid was added to this mixture, and the mixture was stirred at 0°C for 30 minutes. 30 g (178 mmol) of 6-chlorobenzofuran-3-one was added thereto, and the mixture was heated to 50°C and stirred for 39 hours. After a predetermined time had passed, the precipitated solid was filtered by suction, and the solid was washed with water, ethanol, and toluene to obtain 7.2 g of a white solid, which was the target product. Water was added to the filtrate obtained here, and the aqueous layer and the organic layer were separated.

The organic layer was washed with saturated saline, dried by adding anhydrous magnesium sulfate, and then naturally filtered. The obtained filtrate was concentrated and the obtained solid was washed with toluene to obtain 4.0 g of the target white solid. The obtained filtrate was purified by silica gel column chromatography. Toluene was initially used as the developing solvent, and the amount of ethyl acetate added was increased so that the final ratio of toluene:ethyl acetate was 2:1, gradually increasing the polarity. The obtained fraction was concentrated and the obtained solid was washed with toluene to obtain 5.4 g of the target white solid (total 17 g, yield 52%). The synthesis scheme of step 1 is shown in (a-1).

<Step 2: Synthesis of 7-chloro[1]benzofuro[3,2-c]pyridazin-3-one>
Next, 22 g (81 mmol) of ethyl 2-(6-chloro-3-oxo-1-benzofuran-2-yl)-2-hydroxyacetate obtained in step 1 above and 340 mL of ethanol were added to a three-neck flask, and 12 g (240 mmol) of hydrazine monohydrate was added thereto. The mixture was stirred at room temperature overnight, and then heated to reflux for 40 hours. The resulting reaction mixture was poured into water and stirred at room temperature. The mixture was suction filtered, and the solid was washed with ethanol to obtain 5.5 g of the target pale orange solid in a yield of 30%. The synthesis scheme of step 2 is shown in (a-2).

<Step 3: Synthesis of 3,7-dichloro[1]benzofuro[3,2-c]pyridazine>
Next, 5.5 g (25 mmol) of 7-chloro[1]benzofuro[3,2-c]pyridazin-3-one obtained in step 2 above and 80 mL of toluene were added to a three-neck flask, and 19 g (125 mmol) of phosphoryl chloride and 0.1 mL of dimethylformamide were added thereto, followed by heating to reflux for 12 hours.

The resulting reaction mixture was neutralized by gradually adding it to an aqueous sodium hydroxide solution in an ice bath. The aqueous and organic layers were separated, and the aqueous layer was extracted with toluene. The resulting organic layer was washed with saturated saline and dried by adding anhydrous magnesium sulfate. The resulting mixture was gravity filtered, and the filtrate was concentrated to obtain a solid. This solid was dissolved in heated toluene and suction filtered through a filter material layered in the order of celite, alumina, and celite. The resulting filtrate was concentrated, and the solid was washed with ethanol to obtain 3.7 g of the desired white solid in a yield of 63%. The synthesis scheme for step 3 is shown in (a-3).

<Step 4: Synthesis of 7-chloro-3-[3-(dibenzothiophen-4-yl)phenyl][1]benzofuro[3,2-c]pyridazine>
Next, 3.1 g (13 mmol) of 3,7-dichloro[1]benzofuro[3,2-c]pyridazine obtained in step 3 above, 4.4 g (14 mmol) of 3-(dibenzothiophen-4-yl)phenylboronic acid, 9.1 g (43 mmol) of tripotassium phosphate, 0.22 g (0.52 mmol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (S-phos), and 130 mL of xylene were placed in a reaction vessel, and the inside of the reaction vessel was degassed and replaced with nitrogen. 63 mg (0.28 mmol) of palladium acetate (II) was added to this mixture, and the mixture was heated and stirred at 120°C for 12 hours. 0.22 g (0.52 mmol) of S-phos and 63 mg (0.28 mmol) of palladium acetate (II) were added to this mixture, and the mixture was heated and stirred at 130°C for 8.5 hours. To this was further added 0.95 g (3.1 mmol) of 3-(dibenzothiophen-4-yl)phenylboronic acid, 2.0 g (9.4 mmol) of tripotassium phosphate, 0.21 g (0.52 mmol) of S-phos, and 59 mg (0.27 mmol) of palladium (II) acetate, and the mixture was heated and stirred for 14 hours at 130° C. To this was further added 0.95 g (3.1 mmol) of 3-(dibenzothiophen-4-yl)phenylboronic acid, 2.0 g (9.4 mmol) of tripotassium phosphate, 0.21 g (0.52 mmol) of S-phos, and 54 mg (0.24 mmol) of palladium (II) acetate, and the mixture was heated and stirred for 7 hours at 130° C. To this, 0.95 g (3.1 mmol) of 3-(dibenzothiophen-4-yl)phenylboronic acid, 1.9 g (9.0 mmol) of tripotassium phosphate, 0.23 g (0.56 mmol) of S-phos, and 71 mg (0.32 mmol) of palladium (II) acetate were further added and heated and stirred at 130°C for 4 hours. The resulting reaction mixture was suction filtered, and the solid was washed with water and ethanol. This solid was dissolved in heated toluene, and 90 g of alumina was added and heated and stirred at 90°C. This mixture was suction filtered through Celite and washed with heated toluene. The resulting filtrate was concentrated to obtain a brown solid. This solid was recrystallized from toluene to obtain 1.6 g of the target white solid in a yield of 27%. The synthesis scheme of step 4 is shown in (a-4).

<Step 5: Synthesis of 3-[3-(dibenzothiophen-4-yl)phenyl]-7-phenyl[1]benzofuro[3,2-c]pyridazine (abbreviation: 7Ph-3mDBtPBfpd)>
Next, 0.53 g (1.1 mmol) of 7-chloro-3-[3-(dibenzothiophen-4-yl)phenyl][1]benzofuro[3,2-c]pyridazine obtained in step 4 above, 0.18 g (1.4 mmol) of phenylboronic acid, 0.62 g (4.1 mmol) of cesium fluoride, and 30 mL of xylene were placed in a reaction vessel, and the atmosphere in the vessel was replaced with nitrogen. After heating the mixture to 60°C while stirring, 27 mg (0.029 mmol) of tris(dibenzylideneacetone)dipalladium(0) and 25 mg (0.069 mmol) of 2'-(dicyclohexylphosphino)acetophenone ethylene ketal were added, and the mixture was heated to 110°C and stirred for 23 hours.

After a certain time had elapsed, 25 mg (0.029 mmol) of tris(dibenzylideneacetone)dipalladium(0) and 26 mg (0.069 mmol) of 2'-(dicyclohexylphosphino)acetophenone ethylene ketal were added to the mixture, and the mixture was heated and stirred at 120°C for 39 hours.

After a predetermined time had elapsed, 0.086 g (0.70 mmol) of phenylboronic acid, 0.3 g (2.0 mmol) of cesium fluoride, 12 mg (0.013 mmol) of tris(dibenzylideneacetone)dipalladium(0), and 13 mg (0.036 mmol) of 2'-(dicyclohexylphosphino)acetophenone ethylene ketal were added to the mixture and heated and stirred for 13 hours.

Water was added to the resulting mixture, which was then suction filtered, and the solid was washed with ethanol. This solid was dissolved in heated toluene and suction filtered through a filter material layered in the following order: Celite, alumina, and Celite. The resulting filtrate was concentrated to obtain a solid. This solid was recrystallized in toluene to obtain 0.23 g of the desired white solid in a yield of 40%. The synthesis scheme for step 5 is shown in formula (a-5) below.

The results of nuclear magnetic resonance spectroscopy ( ¹ H-NMR) analysis of the white solid obtained in step 5 are shown below. The ¹ H-NMR chart is shown in Fig. 8. From these results, it was found that 7Ph-3mDBtPBfpd, an organic compound represented by the above structural formula (100) and which is one embodiment of the present invention, was obtained in this example.

^1H -NMR. δ( _CDCl3 ): 7.44-7.55 (m, 5H), 7.60-7.64 (m, 2H), 7.71-7.76 (m, 3H), 7.80 (dd, 1H), 7.86-7.88 (m, 2H ), 7.92 (ddd, 1H), 8.05 (s, 1H), 8.21-8.24 (m, 2H), 8.32 (d, 1H), 8.51 (d, 1H) , 8.57 (dd, 1H).

<Physical properties of 7Ph-3mDBtPBfpd>
Next, the ultraviolet-visible absorption spectrum (hereinafter simply referred to as "absorption spectrum") and emission spectrum of the toluene solution of 7Ph-3mDBtPBfpd were measured. The absorption spectrum was measured using an ultraviolet-visible spectrophotometer (V550 model, manufactured by JASCO Corporation). The emission spectrum was measured using a fluorometer (FS920, manufactured by Hamamatsu Photonics Corporation). The measurement results of the absorption spectrum and emission spectrum of the obtained toluene solution are shown in FIG. 9. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity.

From the results in Figure 9, the toluene solution of 7Ph-3mDBtPBfpd showed absorption peaks at around 333 nm and 281 nm, and an emission wavelength peak at around 449 nm.

Next, the phosphorescence spectrum of the toluene solution of 7Ph-3mDBtPBfpd was measured. To measure the phosphorescence spectrum, an absolute PL quantum yield measurement device (C11347-01, manufactured by Hamamatsu Photonics K.K.) was used. In a glove box (LABstar M13 (1250/780), manufactured by Bright K.K.), the deoxygenated toluene solution was placed in a quartz cell under a nitrogen atmosphere, sealed, and measured at liquid nitrogen temperature. The measurement results of the obtained phosphorescence spectrum are shown in Figure 10. The horizontal axis represents the wavelength, and the vertical axis represents the emission intensity.

From the results in Figure 10, a phosphorescence spectrum was observed at 479 nm from a toluene solution of 7Ph-3mDBtPBfpd at liquid nitrogen temperature.

The organic compound 7Ph-3mDBtPBfpd, which is one embodiment of the present invention, has a high T1 level and can be said to be a host material suitable for phosphorescent materials (guest materials) that emit light in the green range. The organic compound 7Ph-3mDBtPBfpd, which is one embodiment of the present invention, can also be used as a host material or light-emitting material for phosphorescent materials that emit light in the visible range.

Synthesis Example 2
Example 1 This example describes a synthesis method for 7-(1,1'-biphenyl-3-yl)-3-[3-(dibenzothiophen-4-yl)phenyl][1]benzofuro[3,2-c]pyridazine (abbreviation: 7mBP-3mDBtPBfpd), an organic compound which is one embodiment of the present invention and is represented by structural formula (101) in Embodiment 1. The structure of 7mBP-3mDBtPBfpd is shown below.

<Step 1: Synthesis of 7mBP-3mDBtPBfpd>
1.6 g (3.5 mmol) of 7-chloro-3-[3-(dibenzothiophen-4-yl)phenyl][1]benzofuro[3,2-c]pyridazine obtained in Step 4 of Example 1 (Synthesis Example 1) above, 0.71 g (3.5 mmol) of 3-biphenylboronic acid, 2.2 g (11 mmol) of tripotassium phosphate, 35 mL of diglyme, and 0.79 g (11 mmol) of tert-butanol were placed in a reaction vessel, and the inside of the vessel was degassed and replaced with nitrogen.

The mixture was heated to 60°C, and 16 mg (0.070 mmol) of palladium (II) acetate and 50 mg (0.14 mmol) of di(1-adamantyl)-n-butylphosphine (cataCXiumA) were added, followed by heating and stirring at 90°C for 6.5 hours. 8 mg (0.035 mmol) of palladium (II) acetate and 25 mg (0.070 mmol) of cataCXiumA were further added, followed by heating and stirring at 90°C for 8 hours. Water was added to the resulting reaction mixture, and the solid was filtered by suction and washed with ethanol. The solid was dissolved in heated toluene and filtered by suction through a filter material layered with Celite-alumina-Celite.

The obtained filtrate was concentrated to obtain an oily product. This oily product was purified by silica gel column chromatography. Toluene was used first as the developing solvent, followed by a mixed solvent of toluene:ethyl acetate = 9:1. Ethanol was added to the oily product obtained by concentrating the obtained fraction, and ultrasonic waves were applied to precipitate a solid. This solid was filtered by suction to obtain 1.45 g of the desired white solid with a yield of 71%. The synthesis scheme of step 1 is shown in the following formula (b-1).

The obtained white solid (1.4 g) was purified by train sublimation. The conditions for the sublimation purification were a pressure of 2.13 Pa and a heating temperature of 325°C. After the sublimation purification, the recovered white solid (0.72 g) was again purified by sublimation. The conditions for the sublimation purification were a pressure of 2.45 Pa and a heating temperature of 310°C. After the sublimation purification, the target product 7-(1,1'-biphenyl-3-yl)-3-[3-(dibenzothiophen-4-yl)phenyl][1]benzofuro[3,2-c]pyridazine (abbreviation: 7mBP-3mDBtPBfpd) was obtained in a yield of 0.57 g (white solid, recovery rate 79%).

The results of nuclear magnetic resonance spectroscopy ( ¹ H-NMR) analysis of the white solid obtained in step 1 are shown below. The ¹ H-NMR chart is shown in Fig. 11. From these results, it was found that 7mBP-3mDBtPBfpd, an organic compound represented by the above structural formula (101) and which is one embodiment of the present invention, was obtained in this example.

^1H -NMR. δ(CD ₂ Cl ₂ ): 7.39-7.42 (m, 1H), 7.49-7.54 (m, 4H), 7.60-7.79 (m, 8H), 7.89-7.91 (m , 2H), 7.93(ddd, 1H ), 7.97-7.98 (m, 2H), 8.10 (s, 1H), 8.25-8.27 (m, 2H), 8.31 (d, 1H), 8.52 ( d, 1H), 8.60 (t, 1H).

<<Physical properties of 7mBP-3mDBtPBfpd>>
Next, the ultraviolet-visible absorption spectrum (hereinafter simply referred to as "absorption spectrum") and emission spectrum of the toluene solution of 7mBP-3mDBtPBfpd were measured. A ultraviolet-visible spectrophotometer (V550 model, manufactured by JASCO Corp.) was used to measure the absorption spectrum. A fluorometer (FP8600, manufactured by JASCO Corp.) was used to measure the emission spectrum. The measurement results of the absorption spectrum and emission spectrum of the obtained toluene solution are shown in FIG. 12. The horizontal axis represents wavelength, and the vertical axis represents absorption intensity.

The results in Figure 12 show that in a toluene solution of 7mBP-3mDBtPBfpd, absorption peaks were observed at around 333 nm and 281 nm, and an emission wavelength peak was observed at around 368 nm.

The organic compound 7mBP-3mDBtPBfpd, which is one embodiment of the present invention, has a high T1 level and can be said to be a host material suitable for phosphorescent materials (guest materials) that emit light in the green range. The organic compound 7mBP-3mDBtPBfpd, which is one embodiment of the present invention, can also be used as a host material or light-emitting material for phosphorescent materials that emit light in the visible range.

101 First electrode 102 Second electrode 103 EL layer 103a, 103b EL layer 104 Charge generation layer 111, 111a, 111b Hole injection layer 112, 112a, 112b Hole transport layer 113, 113a, 113b Light emitting layer 114, 114a, 114b Electron transport layer 115, 115a, 115b Electron injection layer 200R, 200G, 200B Optical path 201 First substrate 202 Transistor (FET)
203R, 203G, 203B, 203W: Light-emitting device 204; EL layer 205: Second substrate 206R, 206G, 206B; Color filters 206R', 206G', 206B'; Color filter 207: First electrode 208; Second electrode 209: Black layer (black matrix)
210R, 210G Conductive layer 301 First substrate 302 Pixel section 303 Driver circuit section (source line driver circuit)
304a, 304b Drive circuit section (gate line drive circuit)
305 Sealing material 306 Second substrate 307 Lead wiring 308 FPC
309 FET
310 FET
311 FET
312 FET
313 First electrode 314 Insulator 315 EL layer 316 Second electrode 317 Light-emitting device 318 Region 900 Substrate 901 First electrode 902 EL layer 903 Second electrode 911 Hole injection layer 912 Hole transport layer 913 Light-emitting layer 914 Electron transport layer 915 Electron injection layer 4000 Lighting device 4001 Substrate 4002 Light-emitting device 4003 Substrate 4004 First electrode 4005 EL layer 4006 Second electrode 4007 Electrode 4008 Electrode 4009 Auxiliary wiring 4010 Insulating layer 4011 Sealing substrate 4012 Sealing material 4013 Desiccant 4015 Diffusion plate 4200 Lighting device 4201 Substrate 4202 Light-emitting device 4204 First electrode 4205 EL layer 4206 Second electrode 4207 Electrode 4208 Electrode 4209 Auxiliary wiring 4210 Insulating layer 4211 Sealing substrate 4212 Sealing material 4213 Barrier film 4214 Planarization film 4215 Diffusion plate 5101 Light 5102 Wheel 5103 Door 5104 Display unit 5105 Handle 5106 Shift lever 5107 Seat 5108 Inner rear view mirror 7000 Housing 7001 Display unit 7002 Second display unit 7003 Speaker 7004 LED lamp 7005 Operation key 7006 Connection terminal 7007 Sensor 7008 Microphone 7009 Switch 7010 Infrared port 7011 Recording medium reading unit 7014 Antenna 7015 Shutter button 7016 Image receiving unit 7018 Stand 7020 Camera 7022, 7023 Operation buttons 7024 Connection terminal 7025 Band 7026 Microphone 7029 Sensor 7030 Speakers 7052, 7053, 7054 Information 9310 Portable information terminal 9311 Display unit 9312 Display area 9313 Hinge 9315 Housing

Claims (6)

An organic compound represented by general formula (G1) (excluding the compound represented by formula (2-26)) .

(In formula (G1) , Q represents oxygen or sulfur. A represents a group having a total of 12 to 100 carbon atoms and has one or more of a benzene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, a triphenylene ring, a heteroaromatic ring including a dibenzothiophene ring, a heteroaromatic ring including a dibenzofuran ring, a heteroaromatic ring including a carbazole ring, a benzimidazole ring, and a triphenylamine structure. ^{R 1} to R ⁵ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.)
An organic compound represented by general formula (G2):

(In formula (G2) , Q represents oxygen or sulfur. α represents a phenylene group which may have a substituent, and n represents an integer of 0 to 4. Ht _uni has any one of a pyrrole ring structure, a furan ring structure, and a thiophene ring structure . ^{R 1} to R ⁵ represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.) An organic compound represented by general formula (G3):

(In formula (G3) , Q represents oxygen or sulfur; n represents an integer of 0 to 4; Ht _uni has any one of a pyrrole ring structure, a furan ring structure, and a thiophene ring structure ; ^{R 1} to R ⁵ represent hydrogen, an alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted monocyclic saturated hydrocarbon having 5 to 7 carbon atoms, a substituted or unsubstituted polycyclic saturated hydrocarbon having 7 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 13 carbon atoms, or a substituted or unsubstituted heteroaryl group having 3 to 12 carbon atoms.) In claim 2 or 3,
The Ht _uni is an organic compound represented by any one of the following general formulas (Ht-1) to (Ht-26).


(In formulae (Ht-1) to (Ht-26), Q represents oxygen or sulfur. R ² to R ⁷¹ each represent 1 to 4 substituents, and each independently represents any one of hydrogen, an alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted phenyl group. Ar ¹ represents a substituted or unsubstituted aryl group having 6 to 13 carbon atoms. ) An organic compound represented by structural formula (100) or (101).
A light-emitting device comprising an organic compound according to any one of claims 1 to 5.

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