JP6936980B2 - Manufacturing method of light emitting layer - Google Patents

Description

The present invention is for forming a light emitting layer, which comprises a hole transport layer and / or a light emitting layer and is used for producing a light emitting layer in a method for manufacturing an organic light emitting element useful for electronic devices such as display devices and lighting devices. Regarding the composition. Further, a light emitting element (also referred to as an EL element) having a structure in which an anode, a cathode, and a light emitting organic material (hereinafter referred to as an organic EL material) from which EL (Electro Luminescence0) can be obtained is sandwiched between them is formed on a substrate. The present invention relates to a light emitting device (also referred to as an EL display device) and a method for manufacturing an electronic device having the light emitting device as a display unit (display display or display monitor). The light emitting device is also referred to as OLED (Organic Light Emitting Diodes).

In recent years, the development of a light emitting device (EL display device) using an EL element as a light emitting element utilizing the EL phenomenon of a luminescent organic material has been progressing. Since the EL display device is a self-luminous type, it does not require a backlight like a liquid crystal display device, and has a wide viewing angle, so that it is promising as a display unit of a portable device used outdoors, for example.

A hole transport layer and a light emitting layer are used for the EL element, and there are two types of EL display devices including the EL element, a passive type (simple matrix type) and an active type (active matrix type), both of which are used. It is being actively developed. In particular, the active matrix type EL display device is currently attracting attention. Further, as an organic EL material serving as a light emitting layer which can be said to be the center of an EL element, a small molecule organic EL material and a polymer organic EL material (polymer organic EL material) are being studied.

Patent Document 1 discloses that a light emitting layer or the like is formed by using a nozzle printing method. According to this method, it is possible to form an organic EL material made of a polymer precisely with high throughput without misalignment. However, since the organic solvent contained in the coating liquid is volatilized by heat treatment (baking treatment or firing treatment) in a vacuum to form a light emitting layer or the like made of an organic EL material, vacuum equipment or the like is required. Simplification of the process is considered as an issue. Further, in the nozzle printing method, there is a problem that the light emitting layer or the like cannot be uniformly formed due to the collision energy.

Patent Document 2 describes that a hole transport layer and a light emitting layer are formed by vacuum vapor deposition. However, the invention described in Patent Document 2 manufactures an organic light emitting device capable of high electron injection efficiency and low voltage drive by performing a specific process on the formation of the electron injection layer, and the hole transport layer. As for the light emitting layer, the means for forming the light emitting layer and the like have not been particularly studied, and there is a problem that vacuum equipment and the like are required and the cost is high. Further, since the productivity of vacuum vapor deposition is not high, a method of easily and easily forming a hole transport layer and a light emitting layer has been desired.

Japanese Unexamined Patent Publication No. 2001-189192 JP-A-2007-188870

An object of the present invention is to provide a composition for forming a light emitting layer, which can easily and easily and efficiently form a light emitting layer in an industrially advantageous manner.

As a result of diligent studies to achieve the above object, the present inventors can easily form a light emitting layer using a light emitting layer forming composition characterized by containing a metal complex and a cyclic ester as a solvent. Moreover, it has been found that the light emitting layer can be efficiently and industrially advantageously formed, and it has been found that such a light emitting layer forming composition can solve the above-mentioned conventional problems at once.
In addition, after obtaining the above findings, the present inventors have further studied and completed the present invention.

That is, the present invention relates to the following invention.
[1] A composition for forming a light emitting layer used for forming a light emitting layer, which comprises a metal complex and an oxygen atom-containing cyclic compound as a solvent.
[2] The composition for forming a light emitting layer according to the above [1], wherein the metal complex has a quinoline skeleton or a benzoquinoline skeleton.
[3] The composition for forming a light emitting layer according to the above [1] or [2], wherein the metal complex is an aluminum quinolinol complex.
[4] The composition for forming a light emitting layer according to any one of the above [1] to [3], wherein the metal complex is Alq3.
[5] The composition for forming a light emitting layer according to any one of the above [1] to [4], wherein the oxygen atom-containing cyclic compound is a lactone or a lactam.
[6] The composition for forming a light emitting layer according to any one of the above [1] to [5], wherein the oxygen atom-containing cyclic compound is γ-butyrolactone.
[7] A method for producing a light emitting layer in which a light emitting layer is formed from a raw material solution directly on a substrate or via another layer, wherein the raw material solution emits light according to any one of [1] to [6]. A method for producing a light emitting layer, which comprises a layer-forming composition.
[8] In the formation of the light emitting layer, the raw material solution is atomized or dropleted, the obtained mist or droplet is conveyed onto the substrate by a carrier gas, and the mist or droplet is reacted on the substrate. The production method according to the above [7], wherein the light emitting layer is laminated on the substrate.
[9] A light emitting layer produced by the production method according to the above [7] or [8].
[10] An organic light emitting device having at least an electrode, a hole transport layer, and a light emitting layer, wherein the light emitting layer is the light emitting layer according to the above [9].
[11] An electronic device or a component thereof including the organic light emitting device according to the above [10].
[12] A system including the electronic device or its component according to the above [11].

According to the composition for forming a light emitting layer of the present invention, a light emitting layer can be formed easily, easily, efficiently and industrially advantageously.

It is a schematic block diagram of the film forming apparatus (mist CVD apparatus) used in an Example. It is a schematic schematic block diagram of the module including the organic light emitting element of this embodiment. It is a top view which shows typically the structure of the drive circuit in the module of FIG. It is a figure which shows the measurement result of the fluorescence spectrum of the laminated body obtained in an Example. It is a figure which shows the measurement result of the fluorescence spectrum of the laminated body obtained in an Example.

The composition for forming a light emitting layer of the present invention is a composition for forming a light emitting layer used for forming a light emitting layer, and is characterized by containing a metal complex and an oxygen atom-containing cyclic compound as a solvent. do.

The metal complex can be used as a precursor of the light emitting layer, and is not particularly limited as long as it is a metal compound having a metal-carbon bond or a metal complex having a coordination bond. The metal in the metal complex is not particularly limited, but is preferably beryllium, magnesium, aluminum, gallium, zinc, indium, tin, platinum, palladium, or iridium, and more preferably beryllium, aluminum, gallium, zinc, and the like. Or iridium.

Specific examples of the metal complex include tris (8-quinolinolato) aluminum (hereinafter referred to as Alq ₃ ), tris (4-methyl-8-quinolinolato) aluminum (hereinafter referred to as Almq ₃ ), and bis. (2-Methyl-8-quinolinolato)-(4-hydroxy-biphenylyl) -aluminum (hereinafter referred to as BAlq), bis (2-methyl-8-quinolinolato) -4-phenylphenolato-gallium (hereinafter referred to as BGaq) ), Etc., a metal complex having a quinoline skeleton, tris (2-phenylpyridine), a metal complex having a benzoquinolin skeleton such as bis (10-hydroxybenzo [h] -quinolinato) beryllium (hereinafter referred to as BeBq _2). Iridium (hereinafter referred to as Ir (ppy) ₃ ), bis [2- (3,5-bis (trifluoromethyl) phenyl) pyridinato-N, C ² '] iridium (III) picolinate (hereinafter referred to as Ir (CF ₃₎₎ Ppy) ₂ (pic)), bis [2- (4,6-difluorophenyl) pyridinato-N, C ² '] iridium (III) acetylacetonate (hereinafter referred to as FIR (acac)), bis [ 2- (4,6-difluorophenyl) pyridinato-N, C ² ')] A metal complex having a pyridine skeleton such as iridium (III) picolinate (hereinafter referred to as FIr (pic)), bis [2- (2- (2-) A metal complex having an oxazole skeleton such as hydroxyphenyl) -benzoxazolate] zinc (hereinafter referred to as Zn (BOX) ₂ ), bis [2- (2-hydroxyphenyl) -benzothiazolato] zinc (hereinafter Zn (BTZ) ) ₂ ) and the like, a metal complex having a thiazole skeleton, or a mixture of two or more of these. In the present invention, the metal complex preferably has a quinoline skeleton or a benzoquinoline skeleton, and more preferably has a quinoline skeleton. In the present invention, it is preferable that the metal complex contains an aluminum quinolinol complex because it is excellent in solubility and handleability with an oxygen atom-containing cyclic compound, and it is more preferable that it contains Alq3, and Alq3 is the most preferable. preferable. The metal complex may be a mixture of two or more types of metal complexes, and examples of the two or more types of metal complexes include the above-exemplified metal complexes and the like.

The oxygen atom-containing cyclic compound is a cyclic compound that can be used as a solvent and may have a substituent, and contains one or more oxygen atoms in the hetero atom or the substituent. If so, there is no particular limitation. As the oxygen atom-containing cyclic compound, a cyclic ester or a cyclic amide can be mentioned as a preferable example. The cyclic ester is not particularly limited as long as it can be used as a solvent and is a cyclic ester compound containing an ester functional group in the ring, but in the present invention, the light emitting layer can be formed more efficiently. The cyclic ester is preferably a lactone. Examples of the lactones include lactones such as β-lactones, γ-lactones, δ-lactones, and ε-lactones. Specifically, for example, γ-butyrolactone and γ-valero. Examples thereof include γ-lactones such as lactone, γ-caprolactone, γ-caprylolactone and γ-laurolactone, δ-lactones such as δ-valerolactone, and ε-lactones such as ε-caprolactone. In the present invention, the lactones are preferably γ-lactones, more preferably γ-butyrolactone. The cyclic amide is not particularly limited as long as it can be used as a solvent and is a cyclic amide compound containing an amide group in the ring, but in the present invention, the light emitting layer can be formed more efficiently. The cyclic amide is preferably a lactam. Examples of the lactams include β-lactams, γ-lactams, δ-lactams and the like, and more specifically, for example, γ-butyrolactam, ε-caprolactam, oxidol, ichisan, glycocanidin and the like. Can be mentioned. The oxygen atom-containing cyclic compound may be a mixed solution of two or more types of oxygen atom-containing cyclic compounds, and examples of the two or more types of oxygen atom-containing cyclic compounds include the above-exemplified lactones or lactams. Kind and the like.

The composition for forming a light emitting layer may contain a solvent other than the oxygen atom-containing cyclic compound. Such a solvent is not particularly limited as long as the object of the present invention is not impaired, and may be an organic solvent other than the oxygen atom-containing cyclic compound or an inorganic solvent. It may be a mixed solvent of an organic solvent and an inorganic solvent. Examples of the organic solvent include alcohols, esters, ethers and the like. Examples of the inorganic solvent include water and the like, and more specific examples thereof include pure water, ultrapure water, tap water, well water mineral spring water, mineral water, hot spring water, spring water, fresh water, seawater and the like. In the present invention, when a solvent other than the oxygen atom-containing cyclic compound is used, it is preferable that the solvent is an organic solvent.

The blending ratio of the metal complex in the light emitting layer forming composition is not particularly limited, but is preferably 0.0001 mol% to 90 mol%, more preferably 0.001 mol% to 50 mol%. The blending ratio of the oxygen atom-containing cyclic compound as a solvent in the composition for forming a light emitting layer is not particularly limited, but is preferably 0.01 mol% to 99 mol%, and more preferably 1 mol%. ~ 95 mol%.

Further, an additive may be mixed with the composition for forming a light emitting layer. The additive is not particularly limited and may be a known additive as long as the object of the present invention is not impaired. The blending ratio of the additive in the light emitting layer forming composition is not particularly limited, but is preferably 0.00001 mol% to 30 mol%, more preferably 0.0001 mol% to 10 mol%.

The composition for forming a light emitting layer is obtained by mixing the metal complex with, for example, the oxygen atom-containing cyclic compound. The mixing means is not particularly limited and may be a known mixing means. More specifically, for example, it can be obtained by dissolving the metal complex in a solvent containing the oxygen atom-containing cyclic compound.

According to the composition for forming a light emitting layer of the present invention, a light emitting layer can be produced industrially advantageously. More specifically, for example, a light emitting layer can be formed from a raw material solution containing the composition for forming a light emitting layer directly on a substrate or via another layer by using a known film forming means. The film forming means is not particularly limited as long as the object of the present invention is not impaired, but in the present invention, the mist CVD method is preferable, and more specifically, the raw material solution containing the light emitting layer forming composition is atomized. Alternatively, it is atomized (atomization / droplet formation step), and the obtained mist or droplet is conveyed onto the substrate with a carrier gas (transportation step), and the mist or droplet is reacted on the substrate. It is preferably produced by laminating the light emitting layer on the substrate (deposition step). Hereinafter, such a preferable manufacturing method will be described in more detail.

(Atomization / droplet formation process)
In the atomization / droplet atomization step, the raw material solution is atomized or dropletized. The atomizing means or the droplet forming means is not particularly limited as long as the raw material solution can be atomized or dropletized, and may be a known means. However, in the present invention, the atomizing means or the atomizing means using ultrasonic waves or Dropletization means is preferred. The mist or droplet obtained by using ultrasonic waves has a zero initial velocity and is preferable because it floats in the air. Since it is a possible mist, it is not damaged by collision energy, so it is very suitable. The droplet size is not particularly limited and may be a droplet of about several mm, but is preferably 50 μm or less, and more preferably 100 nm to 10 μm.

(Raw material solution)
The raw material solution contains the composition for forming a light emitting layer, and is not particularly limited as long as it can be atomized or atomized. In the present invention, the composition for forming a light emitting layer may be used as it is as a raw material solution, or a mixed solution further containing other materials may be used as a raw material solution. Examples of other materials include inorganic materials, organic materials, and the like, and the raw material solution may further contain an inorganic material or an organic material as long as the object of the present invention is not impaired. May be good. In addition, the raw material solution may further contain both inorganic and organic materials.

(Transport process)
In the transport step, the mist or the droplets are transported to the substrate installed in the film forming portion (for example, the film forming chamber) by the carrier gas. The carrier gas is not particularly limited as long as the object of the present invention is not impaired, and for example, an inert gas such as oxygen, ozone, nitrogen or argon, or a reducing gas such as hydrogen gas or forming gas is a suitable example. Can be mentioned. Further, the type of the carrier gas may be one type, but may be two or more types, and a diluted gas having a reduced flow rate (for example, a 10-fold diluted gas) or the like is further used as the second carrier gas. May be good. Further, the carrier gas may be supplied not only at one location but also at two or more locations. The flow rate of the carrier gas is not particularly limited, but is preferably 0.01 to 20 L / min, and more preferably 1 to 10 L / min. In the case of a diluting gas, the flow rate of the diluting gas is preferably 0.001 to 2 L / min, more preferably 0.1 to 1 L / min.

(Film formation process)
In the film forming step, the mist or droplets are reacted on the substrate to form a film on the substrate. The reaction may be a reaction by drying, but a thermal reaction by heat is preferable, and the thermal reaction may be any reaction as long as the mist or droplets react with heat, and the reaction conditions and the like also hinder the object of the present invention. Unless otherwise limited. In this step, the thermal reaction is usually carried out at 250 ° C. or lower, but in the present invention, 200 ° C. or lower is preferable, 180 ° C. or lower is more preferable, and 140 ° C. or lower is most preferable. In the present invention, since a good film can be formed even at a low temperature, it can be applied to various types of substrates, and in particular, it has better adhesion without damaging the substrate and better the original properties of the film. Can be demonstrated. The lower limit is not particularly limited as long as the object of the present invention is not impaired, but 80 ° C. or higher is preferable, 100 ° C. or higher is more preferable, and 110 ° C. or higher is most preferable. Further, the reaction may be carried out in any of a vacuum, a non-oxygen atmosphere, a reducing gas atmosphere and an oxygen atmosphere as long as the object of the present invention is not impaired, but the reaction may be carried out in a non-oxygen atmosphere or oxygen. It is preferably performed in an atmosphere. Further, it may be carried out under any conditions of atmospheric pressure, pressurization and depressurization, but in the present invention, it is preferably carried out under atmospheric pressure. The film thickness can be set by adjusting the film formation time. Further, for example, when a linear source type film forming apparatus is used, the film thickness can be appropriately set by adjusting the number of reciprocating scans of the film formation. Further, for example, when a roll-to-roll type film forming apparatus is used, the film thickness can be appropriately set by adjusting the number of nozzles and the like.

Further, in the present invention, a film may be formed directly on the substrate, or may be formed via another layer such as a buffer layer (buffer layer) or a stress relaxation layer. The means for forming other layers such as the buffer layer (buffer layer) and the stress relaxation layer is not particularly limited and may be known means, but in the present invention, the mist CVD method is preferable.

The thickness of the light emitting layer is not particularly limited, but is preferably 1 nm to 100 μm, more preferably 5 nm to 50 μm, and most preferably 10 nm to 10 μm.

(Hypokeimenon)
The substrate is not particularly limited as long as it can support the film to be formed. It may be a stretchable substrate. The material of the substrate is not particularly limited as long as it does not interfere with the object of the present invention, and may be a known substrate, an organic compound, or an inorganic compound. It may be a porous structure. The shape of the substrate may be any shape and is effective for any shape, for example, plate-like, fibrous, rod-like, columnar, prismatic, such as a flat plate or a disk. Cylindrical, spiral, spherical, ring-shaped and the like can be mentioned, but in the present invention, a substrate is preferable. The thickness of the substrate is not particularly limited in the present invention, but is preferably 0.5 μm to 100 mm, more preferably 1 μm to 10 mm.

The substrate is not particularly limited as long as it has a plate shape and serves as a support for a film to be formed. It may be an insulator substrate, a semiconductor substrate, a metal substrate, or a conductive substrate. Further, those in which at least one kind of film of a metal film, a semiconductor film, a conductive film and an insulating film is formed on a part or all of these surfaces can also be suitably used as the substrate. .. In the present invention, the substrate is preferably a glass substrate, and more preferably a glass substrate having at least one of a metal film, a semiconductor film, a conductive film and an insulating film on the surface. .. As the constituent metal of the metal film, for example, one selected from gallium, iron, indium, aluminum, vanadium, titanium, chromium, rhodium, nickel, cobalt, zinc, magnesium, calcium, silicon, yttrium, strontium and barium, or one of them. Two or more kinds of metals and the like can be mentioned. Examples of the constituent materials of the semiconductor film include elemental substances such as silicon and germanium, compounds having elements of groups 3 to 5 and groups 13 to 15 of the periodic table, metal oxides, and metal sulfides. , Metal serene compounds, metal nitrides and the like. Examples of the constituent material of the conductive film include tin-doped indium oxide (ITO), fluorine-doped indium oxide (FTO), antimony-doped tin oxide (ATO), zinc oxide (ZnO), and aluminum-doped zinc oxide (AZO). , Gallium-doped zinc oxide (GZO), tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), tungsten oxide (WO ₃ ), etc., but in the present invention, the conductivity is composed of a conductive oxide. It is preferably a film, more preferably a tin-doped indium oxide (ITO) film or a fluorine-doped indium oxide (FTO) film, and most preferably a tin-doped indium oxide (ITO) film. Examples of the constituent material of the insulating film include aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), silicon oxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ), and silicon oxynitride (Si _4). Examples thereof include O ₅ N ₃ ), and an insulating film made of an insulating oxide is preferable, and a titania film is more preferable.

The means for forming the metal film, the semiconductor film, the conductive film and the insulating film is not particularly limited and may be a known means. Examples of such forming means include a mist CVD method, a sputtering method, a CVD method (vapor deposition method), an SPD method (spray thermal decomposition deposition method), a vapor deposition method, an ALD (atomic layer deposition) method, and a coating method ( For example, dipping, dripping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, etc.).

Further, in the present invention, an anode may be formed on the substrate. The anode may be a known one, and examples of the anode include the conductive film, the metal film, and the like.

The means for forming the anode is not particularly limited as long as the object of the present invention is not impaired, and in the present invention, known means can be used as the means for forming the anode. Examples of the anode forming means include a mist CVD method, a sputtering method, a CVD method (gas phase growth method), an SPD method (spray pyrolysis deposition method), and a vapor deposition method.

The thickness of the anode is not particularly limited and may be appropriately selected depending on the material constituting the anode, but is usually 10 nm to 500 μm, preferably 50 nm to 200 μm.

In the present invention, it is preferable to further form another layer on the substrate on which the anode is formed, and a hole transport layer is further formed on the substrate on which the anode is formed. Is more preferable. The constituent material of the hole transport layer is not particularly limited and may be a known one. In the present invention, the constituent material of the hole transport layer is preferably an amine derivative, more preferably an arylamine derivative, and most preferably a tertiary arylamine derivative or a benzidine-based amine derivative. .. Examples of the tertiary arylamine derivative include 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (abbreviation: α-NPD) and N, N'-bis (3-). Methylphenyl) -N, N'-diphenyl- [1,1'-biphenyl] -4,4'-diamine (abbreviation: TPD), 4,4', 4 "-tris (N, N-diphenylamino) Triphenylamine (abbreviation: TDATA), 4,4', 4''-tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine (abbreviation: MTDATA), N, N'-bis (abbreviation: MTDATA) Spiro-9,9'-bifluoren-2-yl) -N, N'-diphenylbenzidine (abbreviation: BSPB), N, N'-bis (4-methylphenyl) (p-tolyl) -N, N'- Diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 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- (4-diphenylamino] N- (4-diphenylamino) Examples thereof include phenyl) -N-phenylamino] benzene (abbreviation: DPA3B) or a mixture of two or more thereof, and examples of the benzidine amine derivative include 4,4'-bis [N- (1-naphthyl)). -N-phenylamino] biphenyl (abbreviation: α-NPD) and N, N'-bis (3-methylphenyl) -N, N'-diphenyl- [1,1'-biphenyl] -4,4'-diamine (Abbreviation: TPD), N, N'-bis (spiro-9,9'-bifluoren-2-yl) -N, N'-diphenylbenzidine (abbreviation: BSPB), N, N, N', N'- Examples thereof include tetranaphthyl-benzidine (abbreviation: TNB) or a mixture of two or more of these.

The means for forming the hole transport layer is not particularly limited and may be a known means as long as the object of the present invention is not impaired. Examples of the means for forming the hole transport layer include a mist CVD method, a sputtering method, a CVD method (vapor deposition method), an SPD method (spray thermal decomposition deposition method), a vapor deposition method, and an ALD (atomic layer deposition) method. Examples thereof include coating methods (for example, dipping, dripping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, etc.).

The thickness of the hole transport layer is not particularly limited, but is preferably 1 nm to 5 μm, preferably 5 nm to 1 μm, from the viewpoint of reducing the driving voltage, improving the external quantum efficiency, and improving the durability. More preferably, it is 10 nm to 500 nm, and most preferably.

In the present invention, it is preferable to form the light emitting layer on a substrate on which the anode and the hole transport layer are formed in this order on the surface, and by forming the light emitting layer in this way, the light emitting layer is further formed. An organic light emitting device can be efficiently obtained.

By manufacturing as described above, a light emitting layer can be easily and easily, efficiently and industrially advantageously obtained. Further, the film thickness of the obtained light emitting layer can be easily adjusted by adjusting the film formation time.

The light emitting layer is useful for an organic light emitting element or the like. In the present invention, when the light emitting layer is used for an organic light emitting device, it is preferably used as, for example, an anode, a hole transport layer, a light emitting layer, an electron transport layer if desired, and a light emitting layer of an organic light emitting device having at least a cathode. be able to. In this case, for example, an organic light emitting device in which an anode, a hole transport layer, a light emitting layer, an electron transport layer if desired, and a cathode are formed in this order on the substrate can be mentioned as a preferable example, but the present invention is not limited thereto. ..

Hereinafter, a suitable example when the light emitting layer is used for the organic light emitting element will be described. The anode, the hole transport layer, the light emitting layer, optionally an electron transport layer, and a cathode are formed on the substrate in this order.

(Electronic transport layer)
The electron transport layer usually has one of a function of injecting electrons from a cathode, a function of transporting electrons, and a function of blocking holes obtained from an anode. The constituent material of the electron transport layer is not particularly limited and may be a known material. Examples of the constituent materials of the electron transport layer include pyridine, pyrimidine, triazine, imidazole, triazol, oxazol, oxadiazol, fluorenone, anthracinodimethane, anthron, diphenylquinone, thiopyrandioxide, and carbodiimide. , Fluolenilidenemethane, distyrylpyrazine, fluorine-substituted aromatic compounds, heterocyclic tetracarboxylic acid anhydrides such as naphthalene perylene, phthalocyanine, and derivatives thereof (may form fused rings with other rings), 8 Examples thereof include metal complexes of quinolinol derivatives, metal phthalocyanines, and various metal complexes typified by metal complexes having benzoxazole or benzothiazol as ligands.

The thickness of the electron transport layer is not particularly limited, but is preferably 1 nm to 5 μm, more preferably 5 nm to 1 μm, from the viewpoint of reducing the driving voltage, improving the external quantum efficiency, and improving the durability. It is preferably 10 nm to 500 nm, most preferably 10 nm to 500 nm.

The means for forming the electron transport layer is not particularly limited and may be a known means as long as the object of the present invention is not impaired. Examples of the means for forming the electron transport layer include a mist CVD method, a sputtering method, a CVD method (vapor deposition method), an SPD method (spray thermal decomposition deposition method), a vapor deposition method, an ALD (atomic layer deposition) method, and coating. Methods (eg, dipping, dripping, doctor blade, inkjet, spin coating, brush coating, spray coating, roll coater, air knife coating, curtain coating, wire bar coating, gravure coating, inkjet coating, etc.) can be mentioned. In the present invention, it is preferable that the means for forming the electron transport layer is a mist CVD method.

(cathode)
The cathode is not particularly limited as long as it has conductivity and functions as an electrode, and may be a known cathode. For example, even if it is an insulating material, if a conductive substance layer is provided on the side facing the electron transport layer and can be used as an electrode, this can be used as a cathode. In the present invention, it is preferable that the cathode has good contact with the electron transport layer. It is also preferable that the cathode has a small difference in work function from the electron transport layer and is chemically stable. Such materials are not particularly limited, but are metal thin films such as gold, silver, copper, aluminum, platinum, rhodium, magnesium, and indium, carbon, carbon black, conductive polymers, and conductive metal oxides (indium). − Organic conductors such as tin composite oxides, tin oxide doped with fluorine, etc.). The average thickness of the cathode is also not particularly limited, but is preferably about 10 to 1000 nm. The surface resistance of the cathode is not particularly limited, but is preferably low. Specifically, the range of the surface resistance of the cathode is preferably 80 Ω / □ or less, and more preferably 20 Ω / □ or less. The lower limit of the surface resistance of the cathode is preferably as low as possible, and is not particularly limited, but may be 0.1 Ω / □ or more.

The method for forming the cathode is not particularly limited as long as the object of the present invention is not impaired, and known means can be used. Examples of the cathode forming means include a mist CVD method, a sputtering method, a CVD method (gas phase growth method), an SPD method (spray pyrolysis deposition method), and a vapor deposition method.

The organic light emitting element is useful as a light emitting element used in a display device, a lighting device, or the like, and is preferably used in an electronic device or a component thereof provided with the display device, the lighting device, or the like. The electronic device or its parts can be manufactured by using known means.

Hereinafter, preferred embodiments will be shown when the organic light emitting device of the present invention is used in an electronic device or a component thereof. In the module shown in FIG. 2, a region 121 exposed from the sealing substrate is provided on one side of the drive substrate 105, and the wiring of the signal line drive circuit 112 and the scanning line drive circuit 113 is extended to the outside in this region 121. A connection terminal (not shown) is formed. The external connection terminal is provided with a flexible printed wiring board 122 for input / output of signals.

The drive substrate 105 shown in FIG. 3 is formed with, for example, a display area 111, a signal line drive circuit 112 which is a driver for displaying an image, and a scanning line drive circuit 113. A pixel drive circuit 114 is formed in the display area 111. The display area 111 is formed by arranging the organic light emitting elements 101R, 101G, and 101B in a matrix as a whole. The organic light emitting elements 101R, 101G, and 101B are formed in a strip-shaped planar shape, and one pixel is formed by the combination of the organic light emitting elements 101R, 101G, and 101B.

The pixel drive circuit 114 is an active type drive circuit formed under the electrode and including a drive transistor, a write transistor, a capacitor (holding capacitance) Cs, and an organic light emitting element. In the pixel drive circuit 114, a plurality of signal lines 112A are arranged in the column direction, and a plurality of scanning lines 113A are arranged in the row direction. The intersection of each signal line 112A and each scanning line 113A corresponds to any one (sub-pixel) of the organic light emitting elements 101R, 101G, and 101B. Each signal line 112A is connected to a signal line drive circuit 112, and an image signal is supplied from the signal line drive circuit 112 to the source electrode of the write transistor via the signal line 112A. Each scanning line 113A is connected to a scanning line driving circuit 113, and scanning signals are sequentially supplied from the scanning line driving circuit 113 to the gate electrode of the writing transistor via the scanning line 113A.

The module is incorporated into various electronic devices or parts thereof and used as, for example, a display device. The electronic device is not particularly limited as long as it is an electronic device in which the organic light emitting element is used, and examples thereof include a television, a camera, a personal computer, a mobile phone, a smartphone, and a display. Further, the means for incorporating the module into the electronic device or its components is not particularly limited and may be a known means.

Further, the organic light emitting device of the present invention is not particularly limited to the example of the module, and can take any aspect, and a system in which the module, the electronic device, or the like is used is also included in the present invention. .. The system is not particularly limited as long as it is a system in which the organic light emitting element is used, and examples thereof include a lighting system and a communication system.

Hereinafter, examples of the present invention will be described, but the present invention is not limited thereto.

(Example 1)
1. 1. Film formation device The mist CVD device 1 used in this embodiment will be described with reference to FIG. The mist CVD apparatus 1 includes a carrier gas source 2 for supplying a carrier gas, a flow rate control valve 3 for adjusting the flow rate of the carrier gas sent out from the carrier gas source 2, and a mist generation source 4 in which the raw material solution 4a is housed. A container 5 containing water 5a, an ultrasonic transducer 6 attached to the bottom surface of the container 5, a hot plate 8, a substrate 10 placed on the hot plate 8, and a substrate from a mist source 4 It is provided with a supply pipe 9 that connects up to the vicinity of 10.

2. Preparation of raw material solution α-NPD was mixed with γ-butyrolactone and used as a raw material solution. The concentration of α-NPD in the solution was 0.0020 mol / L.

3. 3. Preparation for film formation 2. The raw material solution 4a obtained in 1) was housed in the mist source 4. Next, as the substrate 10, a 15 mm square glass / ITO substrate was placed on the hot plate 8 and the hot plate 8 was operated to raise the temperature of the substrate 10 to 180 ° C. Next, the flow rate control valve 3 was opened to adjust the flow rate of the carrier gas supplied from the carrier gas supply means 2 which is the carrier gas source to 4 L / min. Nitrogen was used as the carrier gas.

4. Formation of hole transport layer Next, the ultrasonic transducer 6 is vibrated at 2.4 MHz, and the vibration is propagated to the raw material solution 4a through water 5a to atomize the raw material solution 4a and generate mist 4b. I let you. This mist 4b is conveyed to the substrate 10 by the carrier gas through the inside of the supply pipe 9, and the mist thermally reacts in the vicinity of the substrate 10 at 180 ° C. under atmospheric pressure to cause holes on the substrate 10. A transport layer was formed. The film thickness of the obtained hole transport layer was about 50 nm, and the film formation time was 10 minutes. Moreover, the fluorescence spectrum of the obtained laminate was measured at an excitation wavelength of 300 nm. The result is shown in FIG. As can be seen from FIG. 4, the obtained laminate had an emission peak at a wavelength of 430 to 450 nm.

5. Formation of light emitting layer Alq3 was used instead of α-NPD to prepare a mixed solution with a concentration of Alq3 in the solution of 0.0025 mol / L, and this was used as a raw material solution. In the same manner as in the formation of the hole transport layer, the above 4. A light emitting layer was formed on the hole transport layer formed in 1. The film thickness of the obtained light emitting layer was about 50 nm, and the film forming time was 10 minutes. Moreover, the fluorescence spectrum of the obtained laminate was measured at an excitation wavelength of 300 nm. The result is shown in FIG. As can be seen from FIG. 5, the obtained laminate had an emission peak at a wavelength of 500 to 520 nm.

6. Formation of cathode 5. Aluminum was formed as a cathode on the light emitting layer formed by the above using a vacuum vapor deposition method to produce an organic light emitting device.

(Example 2)
An organic light emitting device was produced in the same manner as in Example 1 except that the film formation temperature at the time of forming the hole transport layer and the light emitting layer was set to 140 ° C. In addition, the fluorescence spectra of the laminates obtained in the hole transport layer forming step (corresponding to 4. of Example 1) and the light emitting layer forming step (corresponding to 5. of Example 1) were measured. The results are shown in FIGS. 4 and 5. As can be seen from FIGS. 4 and 5, the range of wavelengths at which the emission peak was observed is 4. And 5. It was the same as each of the laminates obtained in. Further, the emission intensity is 4. And 5. Each of them was higher than the laminates obtained in 1 and had better light emission characteristics.

When the composition for forming a light emitting layer of the present invention is used, a light emitting layer can be easily, easily, efficiently and industrially advantageously produced, and thus can be used in various industries. In particular, it can be used in industrial fields such as electronic devices equipped with display devices and lighting devices.

1 Mist CVD device 2 Carrier gas source 3 Flow control valve 4 Mist generation source 4a Raw material solution 4b Mist 5 Container 5a Water 6 Ultrasonic transducer 8 Hot plate 9 Supply tube 10 Substrate 101R Organic light emitting element 101G Organic light emitting element 101B Organic light emitting element 105 Drive board 111 Display area 112 Signal line drive circuit 112A Signal line 113 Scan line drive circuit 113A Scan line 114 Pixel drive circuit 121 Area 122 Flexible printed wiring board

Claims (6)

Atomize or dropletize the raw material solution
To the suspended mists or droplets by supplying carrier gas to transport the mist or the droplets to the substrate on the said carrier gas,
A method for producing a light emitting layer, which is formed by thermally reacting the mist or droplets on the substrate and laminating a light emitting layer directly on the substrate or via another layer.
A method for producing a light emitting layer, wherein the raw material solution contains a metal complex and an oxygen atom-containing cyclic compound as a solvent. The method for producing a light emitting layer according to claim 1, wherein the metal complex has a quinoline skeleton or a benzoquinoline skeleton. The method for producing a light emitting layer according to claim 1 or 2, wherein the metal complex is an aluminum quinolinol complex. The method for producing a light emitting layer according to any one of claims 1 to 3, wherein the metal complex is Alq3. The method for producing a light emitting layer according to any one of claims 1 to 4, wherein the oxygen atom-containing cyclic compound is a lactone or a lactam. The method for producing a light emitting layer according to any one of claims 1 to 5, wherein the oxygen atom-containing cyclic compound is γ-butyrolactone.

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