JP4134280B2 - Organic electroluminescence device and full-color light emitting device - Google Patents

Description

  The present invention relates to an organic electroluminescence element and a full-color light emitting device using the same.

  In recent years, white organic electroluminescence elements (organic EL elements) have been actively developed because they can be used for mono-color display devices, lighting applications such as backlights, and full-color display devices using color filters. ing. In particular, when a white organic EL element is used for illumination, a white organic EL element having high luminous efficiency that is equal to or higher than the luminous efficiency of a fluorescent lamp, for example, is required.

  Many methods for obtaining white light emission with an organic EL element have been disclosed. In these methods, there are few that obtain a white color with only one kind of light emitting material, and usually two or three kinds of light emitting materials are caused to emit light simultaneously in one organic EL element. When two types of luminescent materials are used, a yellow to red luminescent material that is complementary to the blue color is selected. However, yellow to red luminescent materials are often strong, resulting in a reddish white color. It tends to be.

  With respect to this problem, in Patent Document 1, in the type in which the light-emitting layer is divided into two, the light-emitting color tends to be biased to red by making the light-emitting layer on the anode side where the light-emitting region of the light-emitting layer tends to be biased into a blue light-emitting layer Has been found to be able to cancel out, and has proposed a white element with suppressed color change. However, the luminous efficiency is not always at a sufficient level.

  Patent Document 2 discloses an organic EL element in which a light emitting layer is laminated in the order of a red light emitting layer, a blue light emitting layer, and a green light emitting layer from the anode side. Furthermore, a technique for suppressing a color change accompanying an increase in drive current by doping a red light-emitting layer with a red dopant used in a red light-emitting layer is also disclosed. However, the luminous efficiency is not always at a sufficient level.

On the other hand, several techniques for providing a charge barrier layer between a plurality of light emitting layers have been disclosed as techniques for emitting white light in a balanced manner.
For example, Patent Document 3 discloses an organic EL device that emits white light by laminating an anode, a hole transporting blue light emitting layer, an electron transporting carrier recombination region control layer, an electron transporting red light emitting layer, and a cathode in this order. . However, since the affinity level of the carrier recombination region control layer was larger than the affinity level of the hole transporting blue light emitting layer, the driving voltage was high. In addition, electrons are less likely to be injected into the hole-transporting blue light-emitting layer with the driving time, the light-emission intensity of the hole-transporting blue light-emitting layer is reduced, and the emission color tends to be biased toward the red light emission of the electron-transporting light-emitting layer. It was.

  Patent Document 4 discloses a white light-emitting organic EL element in which two electron-transporting light-emitting layers are arranged via a charge barrier layer. However, the holes injected from the anode are almost consumed in the first light-emitting layer, and the amount of holes supplied through the charge barrier layer to the second electron-transporting light-emitting layer is small. There was a problem that light emission efficiency was low.

  In Patent Document 5, an anode, a first light emitting layer, a charge barrier layer, a second light emitting layer, and a cathode are stacked in this order, and the ionization potential of the charge barrier layer is 0.1 eV or more than the ionization potential of the first light emitting layer. There is disclosed a white light-emitting organic EL device that is made larger and has an affinity level of the charge barrier layer that is 0.1 eV or less lower than that of the second light-emitting layer. However, since the charge barrier layer has both functions of an electron barrier and a hole barrier, there is a problem that a driving voltage becomes high.

In addition, Patent Document 6 and Patent Document 7 disclose white elements, but neither of them has sufficient luminous efficiency.
JP 2003-272857 A JP 2004-235168 A JP-A-8-78163 International Publication No. 2005/099313 Pamphlet International Publication No. 2005/112518 Pamphlet Japanese Patent Laid-Open No. 2005-10091 US Publication No. 2006/0088729

  In view of the above problems, an object of the present invention is to provide an organic EL element that has color rendering properties suitable for display and lighting applications, has high luminous efficiency, and has little change in chromaticity.

  In order to solve this problem, the present inventors have intensively studied. As a result, they have found that the following elements have high color rendering properties and light emission efficiency and have little change in chromaticity, thereby completing the present invention.

According to the present invention, the following organic EL element and full color light emitting device are provided.
1. An anode, a first light emitting layer, a charge barrier layer, a second light emitting layer, and a cathode are laminated in this order,
The first light emitting layer and the second light emitting layer each contain a host material and a dopant,
The energy gap of the host material of the first light emitting layer is smaller than the energy gap of the host material of the second light emitting layer;
The host material of the first light emitting layer is a hole transporting material, the host material of the second light emitting layer is an electron transporting material,
The affinity level of the charge barrier layer is 0.2 eV or more smaller than the affinity level of the host material of the second light emitting layer,
An organic electroluminescence device in which an ionization potential (Ie1) of the charge barrier layer and an ionization potential (Ih1) of a host material of the first light emitting layer satisfy the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1)
2. An anode, a first light-emitting layer, a charge barrier layer, a second light-emitting layer, a third light-emitting layer and a cathode are laminated in this order,
The first light emitting layer, the second light emitting layer, and the third light emitting layer each contain a host material and a dopant,
The energy gap of the host material of the first light emitting layer is smaller than the energy gap of the host material of the second light emitting layer;
The host material of the first light emitting layer is a hole transporting material;
The host material of the second light emitting layer and the third light emitting layer is an electron transporting material,
The charge barrier layer is a hole transporting material;
An organic electroluminescence device in which an ionization potential (Ie1) of the charge barrier layer and an ionization potential (Ih1) of a host material of the first light emitting layer satisfy the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1)
3. 3. The organic electroluminescence device according to 2, wherein the affinity level of the charge barrier layer is 0.2 eV or less smaller than the affinity level of the host material of the second light emitting layer.
4). 4. The organic electroluminescence device according to any one of 1 to 3, wherein the energy gap of the host material of the first light emitting layer is 0.4 eV or less smaller than the energy gap of the host material of the second light emitting layer.
5. 2. The organic electroluminescence device according to 1, wherein the dopant of the first light emitting layer is a red dopant, and the dopant of the second light emitting layer is a blue dopant.
6). The organic electroluminescent device according to 2 or 3, wherein the dopant of the first light emitting layer is a red dopant, the dopant of the second light emitting layer is a blue dopant, and the dopant of the third light emitting layer is a green dopant.
7). The organic electroluminescence device according to any one of 1 to 6, wherein the charge barrier layer contains a light emitting material.
8). 8. The organic electroluminescence device according to 7, wherein the light emitting material of the charge barrier layer is a green dopant.
9. The organic electroluminescence device according to any one of 1 to 8, which has a hole transport layer adjacent to the first light emitting layer between the anode and the first light emitting layer.
10. 10. The organic electroluminescence device according to 9, wherein the material forming the hole transport layer and the material forming the charge barrier layer are the same material.
11. The first light-emitting layer or the first organic layer that is an organic layer close to the anode contains an oxidizing agent, and / or the second light-emitting layer or the second organic layer that is an organic layer close to the cathode is reduced. The organic electroluminescent element in any one of 1-10 containing the agent.
12 The host material of the first light emitting layer is a compound represented by the following formula (1), and the dopant of the first light emitting layer is any one of 1 to 11 which is a compound having a fluoranthene skeleton or a perylene skeleton. Organic electroluminescence device.
X- (Y) n (1)
(Wherein X is a condensed aromatic ring group having 3 or more carbon rings,
Y is a group selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted diarylamino group, a substituted or unsubstituted arylalkyl group, or a substituted or unsubstituted alkyl group;
n is an integer of 1 to 6, and when n is 2 or more, Y may be the same or different. )
13. 13. The organic electroluminescence device according to 12, wherein the compound having a fluoranthene skeleton or a perylene skeleton is an indenoperylene derivative represented by the following formula (2) or formula (3).
(In the formula, Ar ¹ , Ar ² and Ar ³ are each a substituted or unsubstituted aromatic ring group or a substituted or unsubstituted aromatic heterocyclic group, and X ^{1 to} X ¹⁸ are hydrogen, halogen and alkyl, respectively. Group, alkoxy group, alkylthio group, alkenyl group, alkenyloxy group, alkenylthio group, aromatic ring-containing alkyl group, aromatic ring-containing alkyloxy group, aromatic ring-containing alkylthio group, aromatic ring group, aromatic heterocyclic group, aromatic ring Oxy group, aromatic ring thio group, aromatic alkenyl group, alkenyl aromatic ring group, amino group, carbazolyl group, cyano group, hydroxyl group, -COOR ^{1 ′} (R ^{1 ′} is hydrogen, alkyl group, alkenyl group, aromatic ring-containing alkyl is a group or an aromatic ring ^{group), -. COR 2 '(} R 2' is hydrogen, an alkyl group, an alkenyl group, an aromatic ring-containing alkyl group, aromatic ring group or amino In a), or -OCOR ^{3 '(R 3'} is adjacent group ^.X 1 ^{to X 18} is an alkyl group, an alkenyl group, an aromatic ring-containing alkyl group or aromatic ring group) is bonded to each other Or may form a ring together with the substituted carbon atom.)
14 14. The organic electroluminescence device according to 13, wherein the indenoperylene derivative is a dibenzotetraphenyl perifuranthene derivative.
15. The organic electroluminescent element according to any one of 12 to 14, wherein the host material of the first light emitting layer has 4 or more condensed rings and the host material of the second light emitting layer has 3 or less condensed rings.
16. The organic electroluminescence device according to any one of 12 to 15, wherein the compound represented by the formula (1) is a naphthacene derivative represented by the following formula (4).
(In Formula (4), Q ^{1 to} Q ¹² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 nuclear carbon atoms, Amino group, substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 20 nuclear carbon atoms, substituted or unsubstituted An arylthio group having 6 to 20 nuclear carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 20 carbon atoms, or a substituted or unsubstituted 5 to 5 nuclear atoms. Represents 20 heterocyclic groups, which may be the same or different.)
17. 17. The organic electroluminescence device according to 16, wherein at least one of Q ¹ , Q ² , Q ³ and Q ^{4 in} the naphthacene derivative represented by the formula (4) is an aryl group.
18. 18. The organic electroluminescence device according to 17, wherein the naphthacene derivative represented by the formula (4) is represented by the following formula (5).
(In the formula ^{(5), Q 3 ~Q 12} , Q 101 ~Q 105, Q 201 ~Q 205 each independently represent the same group in the general formula (1) was ^Q 3 ^{to Q 12,} which are They may be the same or different, and two or more adjacent groups may be bonded to each other to form a ring.)
19. In the naphthacene derivative represented by the formula (5), at least one of Q ¹⁰¹ , Q ¹⁰⁵ , Q ²⁰¹ and Q ²⁰⁵ is an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, 19. The organic electroluminescence device according to 18, which is an alkenyl group, an aralkyl group or a heterocyclic group, and these may be the same or different.
20. The organic electroluminescence device according to any one of 12 to 19, wherein the charge barrier layer contains a tertiary amine compound, a carbazole derivative, a compound containing a nitrogen-containing heterocyclic ring, or a metal complex.
21. The organic electroluminescence device according to any one of 1 to 20 which emits white light,
A full-color light emitting device including a color filter.

  According to the present invention, it is possible to provide an organic EL element having color rendering properties, high luminous efficiency and little change in chromaticity.

It is a figure which shows the structure of the organic EL element concerning Embodiment 1 of this invention. It is a figure which shows the energy level of the 1st light emitting layer, charge barrier layer, and 2nd light emitting layer of the organic EL element shown in FIG. It is a figure which shows the structure of the organic EL element concerning Embodiment 2 of this invention. It is a figure which shows the structure of the organic EL element concerning Embodiment 3 of this invention. It is a figure which shows the energy level of the 1st light emitting layer, the 1st charge barrier layer, and the 2nd light emitting layer which were produced in Example 1. FIG. It is a figure which shows the energy level of the 1st light emitting layer created in the comparative example 4, the 1st electric charge barrier layer, and the 2nd light emitting layer. It is a figure which shows the energy level of the 1st light emitting layer created in the comparative example 5, the 1st electric charge barrier layer, and the 2nd light emitting layer. It is a figure which shows the value of CIE1931 chromaticity x with respect to the brightness | luminance of the organic EL element produced by the comparative example 1 and Examples 1-4. It is a figure which shows the value of CIE1931 chromaticity y with respect to the brightness | luminance of the organic EL element produced by the comparative example 1 and Examples 1-4.

Embodiment 1
The organic EL device according to Embodiment 1 of the present invention includes an anode, a first light emitting layer, a charge barrier layer, a second light emitting layer, and a cathode stacked in this order. The first light emitting layer and the second light emitting layer each contain a host material and a dopant.
Here, the first light emitting layer includes a hole transporting material as a host material, and the second light emitting layer includes an electron transporting material as a host material. Furthermore, the energy gap of the host material of the first light emitting layer is smaller than the energy gap of the host material of the second light emitting layer.
In addition, the affinity level of the charge barrier layer is 0.2 eV or more lower than the affinity level of the host material of the second light emitting layer, and the ionization potential (Ie1) of the charge barrier layer and the ionization potential (Ih1) of the host material of the first light emitting layer. ) Satisfies the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1)

Preferably, the affinity level (Afe1) of the charge barrier layer is larger than 1 eV and smaller than the affinity level (Afh2) of the host material of the second light emitting layer by 0.2 eV or more (satisfying the following formula).
1 <Afe1 ≦ Afh2-0.2 (eV)

Preferably, the ionization potential (Ie1) of the charge barrier layer and the ionization potential (Ih1) of the host material of the first light emitting layer satisfy the following formula.
2.5 <Ie1 <Ih1 + 0.1 (eV)

Preferably, the energy gap (Egh1) of the host material of the first light emitting layer is larger than 1.5 eV, and is smaller than the energy gap (Egh2) of the host material of the second light emitting layer by 0.4 eV or more (satisfying the following formula).
1.5 <Egh1 ≦ Egh2-0.4 (eV)

FIG. 1 is a diagram illustrating an example of a configuration of an organic EL element according to the first embodiment.
An organic EL element 10 shown in FIG. 1 has a structure in which an anode 1, a hole transport layer 2, a first light emitting layer 3, a charge barrier layer 4, a second light emitting layer 5, an electron transport layer 6 and a cathode 7 are laminated. ing.
The first light emitting layer 3 and the second light emitting layer 5 contain a host material and a dopant, respectively.
In the element 10, for example, white light emission can be obtained by making the first light emitting layer 3 emit red light and the second light emitting layer 5 emit blue light. The reason why the second light-emitting layer 5 is doped with a blue dopant is to make blue that emits light weakly well and to balance white.

  In the organic EL element 10, the host material of the first light emitting layer 3 close to the anode 1 side is a hole transporting material, and the host material of the second light emitting layer 5 close to the cathode 7 side is an electron transporting material. A charge barrier layer 4 is provided between the first light emitting layer 3 and the second light emitting layer 5. By doing so, the electron injection into the first light-emitting layer 3 and the hole injection into the second light-emitting layer 5 are performed in a well-balanced manner, and the charge blocking layer 4 and the second light emitting layer are The recombination region concentrates around the interface. Then, since the second light emitting layer 5 is doped with a blue dopant, blue light emission can be obtained efficiently. Blue light emission is generally weak, but strong blue light emission can be obtained. In the first light emitting layer 3, the energy of the blue light emitted from the second light emitting layer 5 is also applied to the red light of the first light emitting layer 3 together with the recombination of the electrons injected through the charge barrier layer and the holes from the anode side. The red light emission is also obtained by moving. Therefore, white light emission with high efficiency and excellent color balance can be obtained.

Here, “hole transportability” in the present invention means that the hole mobility of the layer is larger than the electron mobility in an electric field range of 10 ² to 10 ⁸ V / cm. Preferably, the hole mobility of the first light emitting layer is 10 ⁻⁵ cm ² / V · sec or more.
Further, “electron transportability” means that the electron mobility of the layer is larger than the hole mobility in the electric field range of 10 ² to 10 ⁸ V / cm. Preferably, the electron mobility of the second light emitting layer is 10 ⁻⁶ cm ² / V · sec or more.
Hole or electron mobility is measured by the Time of flight method.

In addition, when the host material of both the first light emitting layer and the second light emitting layer is an electron transporting material, the recombination region is biased toward the first light emitting layer as in Patent Document 4 of the prior art, and a good white color is obtained. It is difficult to obtain luminescence.
In addition, when the host materials of the first light emitting layer and the second light emitting layer are both hole transporting materials, the recombination region is biased toward the second light emitting layer contrary to the above, and good white light emission is obtained. Hateful. In addition, the recombination region tends to be biased particularly toward the cathode side in the second light emitting layer. For this reason, the light emission efficiency is lowered by the quenching action of the metal cathode.
When the host material of the first light emitting layer is an electron transporting material and the host material of the second light emitting layer is a hole transporting material, electron injection into the first light emitting layer and holes into the second light emitting layer are performed. Both injections are less likely to occur, resulting in a significant increase in drive voltage.
Further, as in Patent Document 3, consider a case where an anode, a hole transporting blue light emitting layer, an electron transporting carrier recombination region control layer, an electron transporting red light emitting layer, and a cathode are stacked in this order.
In this case, since the blue energy gap is large, the affinity level of the hole transporting blue light emitting layer is lowered. The affinity level of the electron transporting carrier recombination region control layer is generally high. Therefore, the electron injection barrier from the electron transporting carrier recombination region control layer to the hole transporting blue light emitting layer is increased, and the driving voltage of the device is increased as a whole.
In this regard, with the configuration of the present embodiment, since the blue light emitting layer is disposed on the cathode side of the charge barrier layer, the gap of the affinity level does not become too large, and high voltage can be prevented.

In the organic EL element 10, the affinity level of the charge barrier layer 4 is 0.2 eV or less smaller than the affinity level of the host material of the second light emitting layer 5. Further, the ionization potential (Ie1) of the charge barrier layer 4 and the ionization potential (Ih1) of the host material of the first light emitting layer 3 satisfy the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1)
This relationship will be described with a diagram showing energy levels.

  FIG. 2 shows the energy levels of the host material of the first light emitting layer 3, the charge barrier layer 4, and the host material of the second light emitting layer 5 of the organic EL element 10. In this figure, the upper side indicates the affinity level of each layer, and the lower side indicates the ionization potential. In the energy level diagram, the lower part shows a larger value. In each layer, the difference between the ionization potential and the affinity level corresponds to the energy gap.

In the organic EL element 10, the affinity level of the charge barrier layer 4 is 0.2 eV or less smaller than the affinity level of the second light emitting layer 5. That is, in FIG. 2, the affinity level of the charge barrier layer 4 is located 0.2 eV or more higher than the affinity level of the second light emitting layer 5 (ΔAf ₁ is 0.2 eV or more in FIG. 2).
The charge barrier layer 4 is a layer that restricts the injection of electrons from the second light-emitting layer 5 closer to the cathode 7 to the first light-emitting layer 3 closer to the anode 1. It is provided to control the recombination amount of the hole pair and adjust the light emission amount from each light emitting layer. Considering this function, it is necessary to have an affinity level that is 0.2 eV or less smaller than the affinity level of the host material of the second light emitting layer. Preferably, it has a small affinity level of 0.5 eV or more.
The relationship between the affinity level of the host material of the first light emitting layer 3 and the affinity level of the charge barrier layer 4 is not particularly limited, but from the viewpoint of driving voltage, the affinity level of the charge barrier layer 4 is preferably 0 eV or less. .

In the organic EL element 10, the ionization potential (Ie1) of the charge barrier layer 4 and the ionization potential (Ih1) of the host material of the first light emitting layer 3 satisfy the above (1). This is to prevent the drive voltage from increasing when the charge barrier layer 4 becomes a barrier for holes, and to prevent this.
The relationship between the ionization potential (Ie1) of the charge barrier layer 4 and the ionization potential (Ih1) of the host material of the first light emitting layer 3 preferably satisfies the following formula (1 ′).
Ie1 <Ih1-0.2 (eV) (1 ')

In the organic EL element 10, the energy gap of the host material of the first light emitting layer 3 is smaller than the energy gap of the host material of the second light emitting layer 5, preferably 0.4 eV or more. When the energy gap of the host material of the first light emitting layer 3 is larger or smaller than 0.4 eV, the difference in affinity level between the second light emitting layer 5 and the charge barrier layer 4 becomes too large. There are cases where the supply of electrons to one light-emitting layer 3 becomes too small to obtain good white light emission. Specifically, the energy gap of the host material of the first light emitting layer 3 is preferably 1.8 to 2.8 eV, and the energy gap of the host material of the second light emitting layer 5 is preferably 2.2 to 3.3 eV.
When the dopant of the first light emitting layer 3 is a red dopant and the dopant of the second light emitting layer 5 is a blue dopant, the first light emitting layer 3 emits red light and the second light emitting layer 5 emits blue light. In addition to emitting light, balanced white light emission can be obtained by satisfying the above requirements.

The reason why the energy of the host material of the first light emitting layer is preferably smaller than the energy of the host material of the second light emitting layer is not clear, but is considered as follows.
Since the color in which the emission intensity is difficult to obtain is blue, excitons are generated mainly using this blue to emit light. Therefore, blue is preferably located on the cathode side of the electron barrier layer. Then, red is arranged on the anode side of the electron barrier layer. When such an arrangement is performed, excitons are generated in the second light emitting layer (blue) which is the cathode side of the electron barrier layer, and this blue is well illuminated. Since the second light emitting layer has a wider energy gap than the first light emitting layer, the energy is moved to the first light emitting layer side. As a result, the red color of the second light emitting layer also shines.

In addition, the element structure of this embodiment is not limited to FIG. 1, For example, the following structures may be sufficient.
1. 1. Anode / first light emitting layer / charge barrier layer / second light emitting layer / cathode 2. Anode / hole transport layer / first light emitting layer / charge barrier layer / second light emitting layer / cathode 3. Anode / first light emitting layer / charge barrier layer / second light emitting layer / electron transport layer / cathode 4. Anode / hole transport layer / first light emitting layer / charge barrier layer / second light emitting layer / electron transport layer / cathode 5. Anode / hole injection layer / hole transport layer / first light emitting layer / charge barrier layer / second light emitting layer / electron transport layer / cathode Anode / hole injection layer / hole transport layer / first light emitting layer / charge barrier layer / second light emitting layer / electron transport layer / electron injection layer / cathode

Among these configurations, it is preferable to have a hole transport layer.
In addition to the layers described above, other organic layers or inorganic layers can be interposed. The intervening layer is not limited as long as it can transport electrons and holes. When it is in the light extraction direction, it is preferably transparent.

Embodiment 2
The organic EL device according to Embodiment 2 includes an anode, a first light emitting layer, a charge barrier layer, a second light emitting layer, a third light emitting layer, and a cathode stacked in this order. Each of the first light emitting layer, the second light emitting layer, and the third light emitting layer contains a host material and a dopant.
Here, the host material of the first light emitting layer is made of a hole transporting material, and the host materials of the second light emitting layer and the third light emitting layer are made of an electron transporting material. Furthermore, the energy gap of the host material of the first light emitting layer is smaller than the energy gap of the host material of the second light emitting layer.
The charge barrier layer is hole transporting. Preferably, the affinity level of the charge barrier layer is 0.2 eV or less smaller than the affinity level of the host material of the second light emitting layer.
Furthermore, the ionization potential (Ie1) of the charge barrier layer and the ionization potential (Ih1) of the host material of the first light emitting layer satisfy the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1)

FIG. 3 is a diagram illustrating an example of the configuration of the organic EL element according to the second embodiment.
3 includes an anode 1, a hole transport layer 2, a first light-emitting layer 3, a charge barrier layer 4, a second light-emitting layer 5, a third light-emitting layer 8, an electron transport layer 6, and a cathode 7. It has a laminated structure. That is, it has the same configuration as that of the first embodiment except that the third light emitting layer 8 is formed. The third light emitting layer 8 also contains a host material and a dopant. Further, the host material of the third light emitting layer 8 is an electron transporting material like the second light emitting layer 5.

In this element 20, for example, the first light emitting layer 3 is formed by using the first light emitting layer 3 as a red dopant, the second light emitting layer 5 as a blue dopant, and the third light emitting layer 8 as a green dopant. By making red light emission, the second light emitting layer 5 blue light emission, and the third light emitting layer 8 green light emission, white light emission with further excellent color rendering can be obtained.
In general, the energy gap of the blue dopant is about 2.8 eV, the energy gap of the green dopant is about 2.5 eV, and the energy gap of the red dopant is about 2.0 eV.

In the present embodiment, the first light emitting layer 3, the charge barrier layer 4, and the second light emitting layer 5 do not necessarily have the relationship as in the first embodiment. This is because the amount of electrons injected into the first light emitting layer 3, the charge barrier layer 4, and the second light emitting layer 5 is limited by forming the third light emitting layer 8. In particular, since the third light emitting layer is doped with a green dopant, electrons are trapped by the green dopant, and electron injection into the second light emitting layer is controlled.
However, in order to further improve the performance of the device, the ionization potential, affinity level, and energy gap of the host material of the first light emitting layer 3, the host material of the charge barrier layer 4 and the second light emitting layer 5 have the same relationship as in the first embodiment. It is preferable to have.

  As in the first embodiment, the element configuration of the present embodiment is not limited to FIG. 3. For example, a configuration in which the third light emitting layer is formed in the element configuration 1-6 exemplified in the first embodiment may be used. These charge barrier layers may be laminated.

In the above embodiment, preferably, the host material of the first light emitting layer is a compound represented by the following formula (1), and the dopant of the first light emitting layer is a compound having a fluoranthene skeleton or a perylene skeleton.
X- (Y) n (1)
(Wherein X is a condensed aromatic ring group having 3 or more carbon rings,
Y is a group selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted diarylamino group, a substituted or unsubstituted arylalkyl group, or a substituted or unsubstituted alkyl group;
n is an integer of 1 to 6, and when n is 2 or more, Y may be the same or different. )

  More preferably, the host material of the first light emitting layer has 4 or more condensed rings. Preferably, the host material of the second light emitting layer has 3 or less condensed rings.

  As described above, the embodiment of the present invention has been described. In the element of the present invention, the anode, the hole transporting first light emitting layer, the charge barrier layer, the electron transporting second light emitting layer, and the cathode are laminated in this order. Configured. By adopting such a configuration, an organic EL element having color rendering properties, high luminous efficiency and little change in chromaticity can be obtained. In addition, the element of the present invention is characterized in that the chromaticity change of light emission is small even when the driving condition (driving voltage or the like) of the element is changed.

Embodiment 3
A full-color light emitting device according to Embodiment 3 of the present invention includes the organic EL element of the present invention that emits white light and a color filter.

FIG. 4 is a diagram illustrating an example of the configuration of the full-color light emitting device according to the third embodiment.
In the full-color light emitting device 100 shown in FIG. 4, first, second, and third (white) organic EL elements 120, 130, and 140 are provided on a support substrate 110. On the side (indicated by arrows), first, second, and third (red, green, and blue) color filters 122, 132, and 142 are arranged to face the elements 120, 130, and 140, respectively. The color filters 122, 132, 142 are formed on the transparent substrate 150.
The light emitted from the organic EL element 120 becomes red light by the color filter 122 and is extracted outside. The light emitted from the organic EL element 130 becomes green light by the color filter 132 and is extracted to the outside, and is emitted from the organic EL element 140. The emitted light is converted into blue light by the color filter 142 and is extracted outside to obtain a full color.

  Sealing between the organic EL elements 120, 130, and 140 and the color filters 122, 132, and 142 to prevent the organic EL element from being deteriorated by the environment, oxygen, moisture, and other volatile components contained in the color filter. A layer or the like may be provided. Specific examples include transparent inorganic compound layers such as SiOxNy, AlOxNy, and SiAlOxNy, and those laminated with these transparent inorganic compound layers and a transparent resin or sealing liquid.

  Examples of the color filters 122, 132, and 142 include the following dyes alone or those in a solid state in which the dyes are dissolved or dispersed in a binder resin.

Red (R) dye: Perylene pigment, lake pigment, azo pigment, etc. Green (G) dye: Halogen polysubstituted phthalocyanine pigment, halogen polysubstituted copper phthalocyanine pigment, trifelmethane basic dye, etc. Blue (B) Color: Copper phthalocyanine pigment, indanthrone pigment, indophenol pigment, cyanine pigment, etc.

  On the other hand, the binder resin is preferably a transparent material (visible light transmittance of 50% or more). For example, transparent resins (polymers) such as polymethyl methacrylate, polyacrylate, polycarbonate, polyvinyl alcohol, polyvinyl pyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose, and photosensitive resins to which a photolithography method can be applied include acrylic acid and methacrylic acid. And a photocurable resist material having a reactive vinyl group. Moreover, when using a printing method, the printing ink (medium) using transparent resin, such as a polyvinyl chloride resin, a melamine resin, a phenol resin, is selected.

  When the color filter is mainly composed of a dye, it is formed by vacuum vapor deposition or sputtering through a mask of a desired color filter pattern. On the other hand, when it is composed of a dye and a binder resin, the dye is mixed with the resin and the resist, Dispersing or solubilizing, forming a film by a method such as spin coating, roll coating, or casting, patterning with a desired color filter pattern by photolithography, or patterning with a desired color filter pattern by a method such as printing It is common.

The film thickness and transmittance of each color filter 122, 132, 142 are preferably as follows.
R: film thickness 0.5-5.0 μm (transmittance 50% or more / 610 nm),
G: Film thickness of 0.5 to 5.0 μm (transmittance of 50% or more / 545 nm),
B: Film thickness of 0.2 to 5.0 μm (transmittance of 50% or more / 460 nm).

  In this embodiment, when providing a full-color light emitting device that emits light of three primary colors of red, green, and blue, a black matrix can be used to improve the contrast ratio.

  Hereinafter, the charge blocking layer, the first light emitting layer, and the second light emitting layer (third light emitting layer), which are characteristic parts of the organic EL element of the present invention, will be mainly described. The other organic layers, inorganic compound layers, anodes, cathodes, and the like and the production methods can be general configurations.

1. Charge blocking layer charge blocking layer, from the viewpoint of not easily become a barrier for holes, hole mobility when an electric field is applied in the ¹⁰ 4 ^~10 7 V / cm, at least ¹⁰ -5 ^cm 2 / V · sec or higher Is preferred.
The thickness of the charge barrier layer is not particularly limited, but is preferably 0.1 to 50 nm. More preferably, it is 0.1-20 nm.

  Various organic compounds and inorganic compounds can be used for the charge barrier layer. As the organic compound, a tertiary amine compound, a carbazole derivative, a compound containing a nitrogen-containing heterocyclic ring, a metal complex, or the like can be used. Inorganic compounds include Ba, Ca, Sr, Yb, Al, Ga, In, Li, Na, K, Cd, Mg, Si, Ta, Ge, Sb, Zn, Cs, Eu, Y, Ce, W, and Zr. , La, Sc, Rb, Lu, Ti, Cr, Ho, Cu, Er, Sm, W, Co, Se, Hf, Tm, Fe, Nb, and other metals, oxides, nitrides, composite oxides, sulfides And fluorides can be used.

Further, from the viewpoint that the charge barrier layer is unlikely to be a barrier against holes, the organic compounds described below that are usually used as a hole transport layer in an organic EL device are preferable.
Specific examples include triazole derivatives (see US Pat. No. 3,112,197), oxadiazole derivatives (see US Pat. No. 3,189,447, etc.), imidazole derivatives (Japanese Patent Publication No. 37-16096). Polyarylalkane derivatives (US Pat. Nos. 3,615,402, 3,820,989, 3,542,544, JP-B-45-555). 51-10983, JP-A-51-93224, 55-17105, 56-4148, 55-108667, 55-156953, 56-36656 Patent Publication etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. Nos. 3,180,729, 4,278,746, Sho 55-88064, 55-88065, 49-105537, 55-51086, 56-80051, 56-88141, 57-45545, 54-112737, 55-74546, etc.), phenylenediamine derivatives (US Pat. No. 3,615,404, JP-B 51-10105, 46-3712, 47- No. 25336, Japanese Patent Laid-Open Nos. 54-53435, 54-110536, 54-1119925, etc.), arylamine derivatives (US Pat. No. 3,567,450, No. 3, 180,703 specification, 3,240,597 specification, 3,658,520 specification, 4,232,103 specification No. 4,175,961, No. 4,012,376, JP-B-49-35702, JP-A-39-27577, JP-A-55-144250, JP-A-56. 119132, 56-22437, West German Patent 1,110,518, etc.), amino-substituted chalcone derivatives (see US Pat. No. 3,526,501, etc.), oxazole derivatives (see U.S. Pat. No. 3,257,203), styryl anthracene derivatives (see JP-A-56-46234, etc.), fluorenone derivatives (see JP-A-54-110837, etc.), hydrazone Derivatives (US Pat. No. 3,717,462, JP-A-54-59143, 55-52063, 55-52064) 55-46760, 55-85495, 57-11350, 57-148799, JP-A-2-311591, etc.), stilbene derivatives (JP-A-61-210363) Gazette, 61-228451, 61-14642, 61-72255, 62-47646, 62-36684, 62-10652, 62-30255 Publication, 60-93455 publication, 60-94462 publication, 60-174749 publication, 60-175052 publication, etc.), silazane derivatives (US Pat. No. 4,950,950), polysilane System (JP-A-2-204996), aniline copolymer (JP-A-2-282263), JP-A-1-21 Conductive polymer oligomers disclosed in 399 JP can (particularly thiophene oligomer).

  Further, porphyrin compounds (disclosed in JP-A-63-295965) etc., aromatic tertiary amine compounds and styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033). Publication No. 54-58445 Publication No. 54-149634 Publication No. 54-64299 Publication No. 55-79450 Publication No. 55-144250 Publication No. 56-119132 Publication No. 61-295558 Publication No. Gazette, 61-98353 gazette, 63-295695 gazette, etc.) can also be used. In particular, it is preferable to use an aromatic tertiary amine compound.

Furthermore, the compound represented by the following formula is also preferable.
In the formula, Ar ^{21 to} Ar ²⁴ are each independently a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, and R ²¹ and R ²² are each independently a hydrogen atom, substituted or unsubstituted. It is an aryl group having 6 to 50 nuclear carbon atoms and an alkyl group having 1 to 50 carbon atoms, and m and n are integers of 0 to 4.

As the aryl group having 6 to 50 nuclear carbon atoms, phenyl, naphthyl, biphenyl, terphenyl, phenanthryl group and the like are preferable. The aryl group having 6 to 50 nuclear carbon atoms may be further substituted with a substituent. Preferred substituents include alkyl groups having 1 to 6 carbon atoms (methyl group, ethyl group, isopropyl group, n- Propyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group, etc.), and an amino group substituted with an aryl group having 6 to 50 nuclear carbon atoms.
As the alkyl group having 1 to 50 carbon atoms, a methyl group, ethyl group, isopropyl group, n-propyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group and the like are preferable.

  In addition, for example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule. ) Biphenyl (NPD), 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type ) -N-phenylamino) triphenylamine (MTDATA) and the like.

A light emitting material may be added to the charge barrier layer. Thereby, light emission including light of various components can be obtained. For example, when the light emitting layer is a first light emitting layer 3 and a second light emitting layer 5 as in the first embodiment, the dopant of the first light emitting layer 3 is a red dopant, the dopant of the second light emitting layer is a blue dopant, The light emitting material of the charge barrier layer is a green dopant. That is, blue having the weakest light emission is arranged in the most luminous area, and green having high visibility is arranged in the next most luminous area. This is because when the green light emission shifts, the color shift can be immediately recognized when viewed by a person, and the white color cannot be balanced. Since red emits light not only by charge injection but also by energy transfer from blue and green, it may be at the position of the first light emitting layer. By arranging in this way, it is possible to realize a three-wavelength white color that is efficient, balanced, and hardly causes color shift. As a luminescent material, the dopant etc. which are used by each light emitting layer mentioned later can be used.
When the charge barrier layer contains a light emitting material, the affinity level and ionization potential of the charge barrier layer are the affinity level and ionization potential of the host material of the charge barrier layer.

2. 1st light emitting layer From the relationship of the energy gap mentioned above, it is preferable that a 1st light emitting layer is yellow-orange or a red light emitting layer. The yellow to orange or red light emitting layer is a light emitting layer having a maximum light emission wavelength of 550 to 650 nm. The light emitting layer is preferably composed of a host material and a yellow to orange or red dopant.
As the host material, a compound represented by the following formula is used.
X- (Y) n
(Wherein X is a condensed aromatic ring group having 3 or more carbon rings,
Y is a group selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted diarylamino group, a substituted or unsubstituted arylalkyl group, or a substituted or unsubstituted alkyl group;
n is an integer of 1 to 6, and when n is 2 or more, Y may be the same or different. )

X is preferably naphthacene, pyrene, anthracene, perylene, chrysene, benzoanthracene, pentacene, dibenzoanthracene, benzopyrene, benzofluorene, fluoranthene, benzofluoranthene, naphthylfluoranthene, dibenzofluorene, dibenzopyrene, dibenzofluorane It is a group containing one or more skeletons selected from ten and acenaphthyl fluoranthene. More preferably, it contains a naphthacene skeleton or an anthracene skeleton.
Y is preferably an aryl group having 12 to 60 carbon atoms or a diarylamino group, and more preferably an aryl group having 12 to 20 carbon atoms or a diarylamino group having 12 to 40 carbon atoms.
n is preferably 2.

Preferably, the compound represented by the formula (1) is a naphthacene derivative represented by the following formula (4).
In formula (4), Q ^{1 to} Q ¹² each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 nuclear carbon atoms, amino Group, substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 20 nuclear carbon atoms, substituted or unsubstituted An arylthio group having 6-20 nuclear carbon atoms, a substituted or unsubstituted alkenyl group having 2-20 carbon atoms, a substituted or unsubstituted aralkyl group having 7-20 carbon atoms, or a substituted or unsubstituted 5-20 carbon atoms These may be the same or different. )

More preferably, it is a compound in which at least one of Q ¹ , Q ² , Q ³ and Q ^{4 in} the naphthacene derivative represented by the formula (4) is an aryl group.

More preferably, the naphthacene derivative represented by the formula (4) is a compound represented by the following formula (5).
(In the formula ^{(5), Q 3 ~Q 12} , Q 101 ~Q 105, Q 201 ~Q 205 each independently represent the same group in the general formula (1) was ^Q 3 ^{to Q 12,} which are These may be the same or different, and two or more adjacent groups may be bonded to each other to form a ring.)

More preferably, at least one of Q ¹⁰¹ , Q ¹⁰⁵ , Q ²⁰¹ and Q ^{205 in} the naphthacene derivative represented by the formula (5) is an alkyl group, aryl group, amino group, alkoxy group, aryloxy group, alkylthio group. , An arylthio group, an alkenyl group, an aralkyl group or a heterocyclic group, which may be the same or different.

  As the yellow to orange or red dopant, a fluorescent compound having at least one fluoranthene skeleton or perylene skeleton can be used, and examples thereof include compounds represented by the following formulas [2] to [18].

(In the formulas [2] to [16], X ^{1 to} X ²⁰ each independently represents a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a linear, branched or cyclic group. An alkoxy group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted carbon atom having 6 carbon atoms -30 arylamino group, substituted or unsubstituted alkylamino group having 1 to 30 carbon atoms, substituted or unsubstituted arylalkylamino group having 7 to 30 carbon atoms, or substituted or unsubstituted carbon atoms 8 to 30 an alkenyl group, when adjacent substituents and X ¹ to X ²⁰ may form a ring structure bonded to. adjacent substituents are aryl groups, the substituents may be the same .)
The compounds of the formulas [2] to [16] preferably contain an amino group or an alkenyl group.

In formulas [17] and [18], X ^{21 to} X ²⁴ are each independently an alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and X ²¹ X ²² and / or X ²³ and X ²⁴ may be bonded via a carbon-carbon bond or —O— or —S—.
X ^{25 to} X ³⁶ are a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, a linear, branched or cyclic alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted carbon An aryl group having 6 to 30 atoms, a substituted or unsubstituted aryloxy group having 6 to 30 carbon atoms, a substituted or unsubstituted arylamino group having 6 to 30 carbon atoms, a substituted or unsubstituted carbon atom of 1 A substituted or unsubstituted arylalkylamino group having 7 to 30 carbon atoms or a substituted or unsubstituted alkenyl group having 8 to 30 carbon atoms, an adjacent substituent, and X ^{25 to} X ^36. May be bonded to form a cyclic structure.
It is preferable that at least one of the substituents X ^{25 to} X ³⁶ in each formula contains an amine or alkenyl group.
Preference is given to indenoperylene derivatives of the formulas [13] and [14].

The fluorescent compound having a fluoranthene skeleton preferably contains an electron donating group in order to obtain high efficiency and a long lifetime, and a preferable electron donating group is a substituted or unsubstituted arylamino group. Furthermore, the fluorescent compound having a fluoranthene skeleton preferably has 5 or more condensed rings, and particularly preferably 6 or more. This is because the fluorescent compound exhibits a fluorescent peak wavelength of 540 to 700 nm, and the blue light emitting material and the fluorescent compound emit light and exhibit a white color.
It is preferable that the fluorescent compound has a plurality of fluoranthene skeletons because the emission color is in a yellow to orange or red region.
A particularly preferred indenoperylene derivative is a dibenzotetraphenyl perifuranthene derivative.

  The thickness of the first light emitting layer is preferably 1 to 50 nm, more preferably 5 to 50 nm. If it is less than 1 nm, the light emission efficiency may be reduced, and if it exceeds 50 nm, the drive voltage may be increased.

3. Second Light-Emitting Layer With respect to the emission color, the second light-emitting layer is preferably a blue light-emitting layer from the relationship of the energy gap. Preferably, the peak wavelength of blue light emission is 450 to 500 nm.
Examples of the dopant that can be used for the second light emitting layer include arylamine compounds and / or styrylamine compounds, anthracene, naphthalene, phenanthrene, pyrene, tetracene, coronene, chrysene, fluorescein, perylene, phthaloperylene, naphthaloperylene, perinone, phthaloperinone, and naphthaloperinone. , Diphenylbutadiene, tetraphenylbutadiene, coumarin, oxadiazole, aldazine, bisbenzoxazoline, bisstyryl, pyrazine, cyclopentadiene, quinoline metal complex, aminoquinoline metal complex, benzoquinoline metal complex, imine, diphenylethylene, vinylanthracene, Diaminocarbazole, pyran, thiopyran, polymethine, merocyanine, imidazole chelating oxinoid compounds, Nakuridon, although rubrene and fluorescent dyes, and the like, but is not limited thereto.

In the organic EL device of the present invention, the second light emitting layer preferably contains an arylamine compound and / or a styrylamine compound.
Examples of the arylamine compound include compounds represented by the following general formula (A), and examples of the styrylamine compound include compounds represented by the following general formula (B).
[In the general formula (A), Ar ₈ is a phenyl, biphenyl, terphenyl, stilbene, a group selected from distyryl aryl, Ar ₉ and _{Ar 10} are each a hydrogen atom or an aromatic number of 6 to 20 carbon Is a group, and Ar _{9 to} Ar ₁₀ may be substituted. p ′ is an integer of 1 to 4. More preferably, Ar ₉ and / or Ar ₁₀ is substituted with a styryl group. ]
Here, as an aromatic group having 6 to 20 carbon atoms, a phenyl group, a naphthyl group, an anthracenyl group, a phenanthryl group, a terphenyl group, and the like are preferable.

[In General Formula (B), Ar _{11 to} Ar ₁₃ are each an optionally substituted aryl group having 5 to 40 nuclear carbon atoms. q ′ is an integer of 1 to 4. ]
Here, as the aryl group having 5 to 40 nuclear atoms, phenyl, naphthyl, anthracenyl, phenanthryl, pyrenyl, coronyl, biphenyl, terphenyl, pyrrolyl, furanyl, thiophenyl, benzothiophenyl, oxadiazolyl, diphenylanthracenyl, Indolyl, carbazolyl, pyridyl, benzoquinolyl, fluoranthenyl, acenaphthofluoranthenyl, stilbene and the like are preferable. The aryl group having 5 to 40 nucleus atoms may be further substituted with a substituent. Preferred substituents include alkyl groups having 1 to 6 carbon atoms (ethyl group, methyl group, isopropyl group, n -Propyl group, s-butyl group, t-butyl group, pentyl group, hexyl group, cyclopentyl group, cyclohexyl group, etc.), C1-C6 alkoxy group (ethoxy group, methoxy group, isopropoxy group, n-propoxy group) Group, s-butoxy group, t-butoxy group, pentoxy group, hexyloxy group, cyclopentoxy group, cyclohexyloxy group, etc.), aryl group having 5 to 40 nuclear atoms, aryl group having 5 to 40 nuclear atoms A substituted amino group, an ester group having an aryl group having 5 to 40 nucleus atoms, an ester group having an alkyl group having 1 to 6 carbon atoms, a cyano group, a nitro group, Androgenic atom (chlorine, bromine, iodine) and the like.

As a host material that can be used for the second light emitting layer, a compound having a structure represented by the following formula (19) having an anthracene central skeleton is preferable.

(In the formula, A ₁ and A ₂ are each independently a group derived from a substituted or unsubstituted aromatic ring having 6 to 20 nuclear carbon atoms. R _{1 to} R ₈ are each independently hydrogen. Atom, substituted or unsubstituted aryl group having 6 to 50 carbon atoms, substituted or unsubstituted heteroaryl group having 5 to 50 nuclear atoms, substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, substituted or unsubstituted A substituted cycloalkyl group having 3 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted nuclear atom number of 5 to 5 50 aryloxy groups, substituted or unsubstituted arylthio groups having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl groups having 1 to 50 carbon atoms, substituted or unsubstituted silyl groups, carboxyl groups, halogen atoms, Cyano group, nitro group It is a hydroxyl group.)

Aromatic rings A ₁ and A ₂ may be substituted with one or more substituents. This substituent is a substituted or unsubstituted aryl group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 50 carbon atoms, a substituted group. Or an unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, and a substituted or unsubstituted nucleus atom. It is selected from an arylthio group having 5 to 50 carbon atoms, a substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, a substituted or unsubstituted silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group.

When the aromatic rings of A ₁ and A ₂ are substituted with two or more substituents, the substituents may be the same or different, and adjacent substituents are bonded to each other to be saturated or unsaturated. The ring structure may be formed.

In the formula (19), A ₁ and A ₂ are preferably different from each other.

  Moreover, the compounds represented by the following (i) to (ix) are preferable.

Asymmetric anthracene represented by the following general formula (i).

(In the formula, Ar is a substituted or unsubstituted condensed aromatic group having 10 to 50 nuclear carbon atoms.
Ar ′ is a substituted or unsubstituted aromatic group having 6 to 50 nuclear carbon atoms.
X ¹ , X ² and X ³ are each independently a substituted or unsubstituted aromatic group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 nuclear atoms, substituted Or an unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, a substituted or unsubstituted number of nuclear atoms 5 ~ 50 aryloxy group, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, carboxyl group, halogen atom, cyano group, nitro group, hydroxyl group It is a group.
a, b, and c are each an integer of 0-4. When a, b and c are 2 or more, X ^{1 s} , X ^{2 s} , and X ^{3 s} may be the same or different.
n is an integer of 1 to 3. When n is 2 or more, the numbers in [] may be the same or different. )

An asymmetric monoanthracene derivative represented by the following general formula (ii).

(In the formula, Ar ¹ and Ar ² are each independently a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms, and m and n are each an integer of 1 to 4, provided that When m = n = 1 and the bonding position of Ar ¹ and Ar ^{2 to} the benzene ring is symmetrical, Ar ¹ and Ar ² are not the same, and m or n is an integer of 2 to 4 M and n are different integers.
R ^{1 to} R ¹⁰ are each independently a hydrogen atom, a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 nuclear atoms, and a substituted group. Or an unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, Substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted A silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group, and a hydroxyl group. )

An asymmetric pyrene derivative represented by the following general formula (iii).

[Wherein, Ar and Ar ′ are each a substituted or unsubstituted aromatic group having 6 to 50 nuclear carbon atoms.
L and L ′ are a substituted or unsubstituted phenylene group, a substituted or unsubstituted naphthalenylene group, a substituted or unsubstituted fluorenylene group, or a substituted or unsubstituted dibenzosilolylene group, respectively.
m is an integer of 0 to 2, n is an integer of 1 to 4, s is an integer of 0 to 2, and t is an integer of 0 to 4.
L or Ar is bonded to any one of positions 1 to 5 of pyrene, and L ′ or Ar ′ is bonded to any of positions 6 to 10 of pyrene.
However, when n + t is an even number, Ar, Ar ′, L, and L ′ satisfy the following (1) or (2).
(1) Ar ≠ Ar ′ and / or L ≠ L ′ (where ≠ indicates a group having a different structure)
(2) When Ar = Ar ′ and L = L ′ (2-1) m ≠ s and / or n ≠ t, or (2-2) When m = s and n = t,
(2-2-1) L and L ′ or pyrene are bonded to different bonding positions on Ar and Ar ′, respectively.
(2-2-2) When L and L ′, or pyrene are bonded at the same bonding position on Ar and Ar ′,
There is no case where the substitution positions in the pyrene of L and L ′ or Ar and Ar ′ are the 1st and 6th positions, or the 2nd and 7th positions. ]

An asymmetric anthracene derivative represented by the following general formula (iv).

(In the formula, A ¹ and A ² are each independently a substituted or unsubstituted condensed aromatic ring group having 10 to 20 nuclear carbon atoms.
Ar ¹ and Ar ² are each independently a hydrogen atom or a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms.
R ^{1 to} R ¹⁰ are each independently a hydrogen atom, a substituted or unsubstituted aromatic ring group having 6 to 50 nuclear carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 5 to 50 nuclear atoms, and a substituted group. Or an unsubstituted alkyl group having 1 to 50 carbon atoms, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkoxy group having 1 to 50 carbon atoms, a substituted or unsubstituted aralkyl group having 6 to 50 carbon atoms, Substituted or unsubstituted aryloxy group having 5 to 50 nucleus atoms, substituted or unsubstituted arylthio group having 5 to 50 nucleus atoms, substituted or unsubstituted alkoxycarbonyl group having 1 to 50 carbon atoms, substituted or unsubstituted A silyl group, a carboxyl group, a halogen atom, a cyano group, a nitro group or a hydroxyl group.
Ar ¹ , Ar ² , R ⁹ and R ¹⁰ may each be plural, and adjacent ones may form a saturated or unsaturated cyclic structure.
However, in the general formula (1), groups that are symmetrical with respect to the XY axis shown on the anthracene do not bond to the 9th and 10th positions of the central anthracene. )

Anthracene derivatives represented by the following general formula (v).

(Wherein R ^{1 to} R ¹⁰ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an optionally substituted aryl group, an alkoxyl group, an aryloxy group, an alkylamino group, an alkenyl group, an arylamino group, or a substituted group. A and b each represent an integer of 1 to 5, and when they are 2 or more, R ¹ or R ² may be the same or different from each other. R ¹ or R ² may be bonded to each other to form a ring, and R ³ and R ⁴ , R ⁵ and R ⁶ , R ⁷ and R ⁸ , R ⁹ and R ¹⁰ L ¹ is a single bond, —O—, —S—, —N (R) — (R is an alkyl group or an aryl group which may be substituted), alkylene Group or arylene group.)

Anthracene derivatives represented by the following general formula (vi).

(In the formula, R ^{11 to} R ²⁰ are each independently a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxyl group, an aryloxy group, an alkylamino group, an arylamino group, or an optionally substituted multicyclic group. C, d, e, and f each represent an integer of 1 to 5, and when they are 2 or more, R ¹¹ , R ¹² , R ^16, or R ¹⁷ may be the same in each case R ¹¹ may be different from each other, R ¹² may be bonded to each other, R ¹⁶ may be bonded to each other, or R ¹⁷ may be bonded to each other to form a ring, or R ¹³ and R ¹⁴ , R ¹⁸ and R ¹⁹ L ² is a single bond, —O—, —S—, —N (R) — (wherein R is an alkyl group or an aryl group which may be substituted), alkylene A group or an arylene group;

Spirofluorene derivatives represented by the following general formula (vii).

(In the formula, A ^{5 to} A ⁸ are each independently a substituted or unsubstituted biphenyl group or a substituted or unsubstituted naphthyl group.)

The condensed ring containing compound represented by the following general formula (viii).

Wherein A ^{9 to} A ¹¹ are each a single bond or a substituted or unsubstituted arylene group having 6 to 50 nuclear carbon atoms, and A ^{12 to} A ¹⁴ are each a hydrogen atom or a substituted or unsubstituted nuclear carbon number 6 R ^{21 to} R ²³ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a cycloalkyl group having 3 to 6 carbon atoms, an alkoxyl group having 1 to 6 carbon atoms, An aryloxy group having 5 to 18 carbon atoms, an aralkyloxy group having 7 to 18 carbon atoms, an arylamino group having 5 to 16 carbon atoms, a nitro group, a cyano group, an ester group having 1 to 6 carbon atoms, or a halogen atom; (At least one of A ^{9 to} A ¹⁴ is a group having three or more condensed aromatic rings.)

A fluorene compound represented by the following general formula (ix).

Wherein R ₁ and R ₂ are a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, or a substituted amino group R ₁ and R ₂ bonded to different fluorene groups may be the same or different, and R ₁ and R ₂ bonded to the same fluorene group are the same. R ₃ and R ₄ may be a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic ring. represents a group, together R ₃ which binds to a different fluorene group, R ₄ each other or different be the same, R ₃ and R ₄ bonded to the same fluorene group .Ar ₁ and Ar ₂ may be different even in the same, the total sum of the three or more substituted or unsubstituted fused polycyclic aromatic group or a benzene ring and a heterocyclic ring is 3 or more benzene rings Represents a condensed polycyclic heterocyclic group bonded to a fluorene group with a substituted or unsubstituted carbon, and Ar ₁ and Ar ₂ may be the same or different, and n represents an integer of 1 to 10. .)

  Among the above host materials, anthracene derivatives are preferable, monoanthracene derivatives are more preferable, and asymmetric anthracene is particularly preferable.

The blue dopant is preferably at least one selected from styrylamine, amine-substituted styryl compounds and condensed aromatic ring-containing compounds. At that time, the blue dopant may be composed of a plurality of different compounds. Examples of the styrylamine and amine-substituted styryl compound include compounds represented by the following formula [20] or [21], and examples of the condensed aromatic ring-containing compound include compounds represented by the following formula [22]. .
[Wherein, Ar ³¹ , Ar ³² and Ar ³³ each independently represent a substituted or unsubstituted aromatic group having 6 to 40 carbon atoms, and p represents an integer of 1 to 3. Preferably, at least one of Ar ³¹ , Ar ³² and Ar ³³ contains a styryl group. ]

[In the formula, Ar ⁴¹ and Ar ⁴² are each independently an arylene group having 6 to 30 carbon atoms, E ¹ and E ² are each independently an aryl group or alkyl group having 6 to 30 carbon atoms, hydrogen An atom or a cyano group is shown, q shows the integer of 1-3. U and / or V is a substituent containing an amino group, and the amino group is preferably an arylamino group. ]

[Wherein, A represents an alkyl group or alkoxy group having 1 to 16 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, a substituted or unsubstituted alkylamino group having 6 to 30 carbon atoms, Or a substituted or unsubstituted arylamino group having 6 to 30 carbon atoms, B represents a condensed aromatic ring group having 10 to 40 carbon atoms, and r represents an integer of 1 to 4. ]

As the green dopant, the same arylamine compound and / or styrylamine compound as the blue dopant described above can be used. Preferably, the peak wavelength of green light emission is 500 to 550 nm.
Preferably, an aromatic amine compound represented by the formula (1) can be used as a green dopant.

In formula (1), A ^{1 to} A ² each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), a substituted or unsubstituted nucleus. An aryl group having 5 to 50 carbon atoms (preferably 5 to 10 nuclear carbon atoms), a substituted or unsubstituted cycloalkyl group having 3 to 20 nuclear carbon atoms (preferably 5 to 10 carbon atoms), substituted or unsubstituted A substituted alkoxy group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), a substituted or unsubstituted aryloxy group having 5 to 50 nuclear carbon atoms (preferably 5 to 10 carbon atoms), substituted or unsubstituted An unsubstituted arylamino group having 5 to 50 nuclear carbon atoms (preferably 5 to 20 nuclear carbon atoms), a substituted or unsubstituted alkylamino group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), Or represents a halogen atom.

Examples of the substituted or unsubstituted alkyl group represented by A ^{1 to} A ² include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, and a heptyl group. Group, octyl group, stearyl group, 2-phenylisopropyl group, trichloromethyl group, trifluoromethyl group, benzyl group, α-phenoxybenzyl group, α, α-dimethylbenzyl group, α, α-methylphenylbenzyl group, α , Α-ditrifluoromethylbenzyl group, triphenylmethyl group, α-benzyloxybenzyl group and the like.

Examples of the substituted or unsubstituted aryl group of A ^{1 to} A ² include a phenyl group, a 2-methylphenyl group, a 3-methylphenyl group, a 4-methylphenyl group, a 4-ethylphenyl group, a biphenyl group, 4- Examples include methylbiphenyl group, 4-ethylbiphenyl group, 4-cyclohexylbiphenyl group, terphenyl group, 3,5-dichlorophenyl group, naphthyl group, 5-methylnaphthyl group, anthryl group, pyrenyl group and the like.

Examples of the substituted or unsubstituted cycloalkyl group represented by A ^{1 to} A ² include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornel group, and an adamantyl group.

Examples of the substituted or unsubstituted alkoxy group of A ^{1 to} A ² include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a butoxy group, an isobutoxy group, a sec-butoxy group, a tert-butoxy group, and various pentyloxys. Group, various hexyloxy groups and the like.

Examples of the substituted or unsubstituted aryloxy group for A ^{1 to} A ² include a phenoxy group, a tolyloxy group, and a naphthyloxy group.
Examples of the substituted or unsubstituted arylamino group for A ^{1 to} A ² include a diphenylamino group, a ditolylamino group, a dinaphthylamino group, and a naphthylphenylamino group.
Examples of the substituted or unsubstituted alkylamino group for A ^{1 to} A ² include a dimethylamino group, a diethylamino group, a dihexylamino group, and the like.
Examples of the halogen atom for A ^{1 to} A ² include a fluorine atom, a chlorine atom, and a bromine atom.
In Formula (1), both A ¹ and A ² are not hydrogen atoms.

In Formula (1), d and e are integers of 1 to 5, respectively, and are preferably 1 to 3. When d and e are each 2 or more, the plurality of A ¹ and A ² may be the same or different, and may be connected to each other to form a saturated or unsaturated ring. Moreover, h is an integer of 1-9, and it is preferable in it being 1-3.

R ¹¹ represents a substituted or unsubstituted secondary or tertiary alkyl group having 3 to 10 carbon atoms, or a substituted or unsubstituted secondary or tertiary cycloalkyl group having 3 to 10 carbon atoms.
The secondary or tertiary alkyl groups, substituted or unsubstituted 3-10 carbon atoms R ^11, for example, isopropyl, tert- butyl group, sec- butyl group, tert- pentyl, 1-methylbutyl group, 1-methylpentyl group, 1,1′-dimethylpentyl group, 1,1′-diethylpropyl group, 1-benzyl-2-phenylethyl group, 1-methoxyethyl group, 1-phenyl-1-methylethyl group, etc. Is mentioned.
The secondary or tertiary substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms R ^11, for example, a cyclopentyl group, a cyclohexyl group, norbornel group, adamantyl group and the like.
In Formula (1), f is an integer of 1-9, and it is preferable in it being 1-3. When f is 2 or more, the plurality of R ¹¹ may be the same or different.

R ¹² represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), a substituted or unsubstituted aryl group having 5 to 50 carbon atoms (preferably a nucleus). 5 to 10 carbon atoms), a substituted or unsubstituted cycloalkyl group having 3 to 20 nuclear carbon atoms (preferably 5 to 10 carbon atoms), a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms (preferably 1-6), a substituted or unsubstituted aryloxy group having 5-50 carbon atoms (preferably 5-10 carbon atoms), a substituted or unsubstituted arylamino group having 5-50 carbon atoms. (Preferably 5 to 20 carbon atoms), a substituted or unsubstituted alkylamino group having 1 to 10 carbon atoms (preferably 1 to 6 carbon atoms), or a halogen atom.
Specific examples of the substituted or unsubstituted alkyl group, aryl group, cycloalkyl group, alkoxy group, aryloxy group, arylamino group, alkylamino group and halogen atom for R ¹² are the same as those described above for A ^{1 to} A ² . Things.
In Formula (1), g is an integer of 0-8, and it is preferable in it being 0-2.
When g is 2 or more, the plurality of R ¹² may be the same or different.
Moreover, in Formula (1), f + g + h is an integer of 2-10, and it is preferable in it being 2-6.

As the aromatic amine compound, compounds represented by formulas (1-1) to (1-7) are more preferable.
[In the formulas (1-1) to (1-7), A ¹ , A ² , d, e, R ¹¹ and R ¹² are the same as those in the formula (1). ]

  The film thickness of the second light emitting layer is preferably 1 to 100 nm, more preferably 5 to 50 nm. If the thickness is less than 1 nm, it is difficult to form a light emitting layer, and it may be difficult to adjust the chromaticity. If the thickness exceeds 100 nm, the driving voltage may increase.

4). Third Light-Emitting Layer With respect to the emission color, the third light-emitting layer is preferably a green light-emitting layer from the relationship of the energy gap. Preferably, the peak wavelength of green light emission is 500 to 550 nm.
As the host material and dopant of the third light emitting layer, those described above can be used. The host material is preferably the same material as the second light emitting layer.

  The thickness of the third light emitting layer is preferably 1 to 100 nm, more preferably 5 to 50 nm. If the thickness is less than 1 nm, it is difficult to form a light emitting layer, and it may be difficult to adjust the chromaticity. If the thickness exceeds 100 nm, the driving voltage may increase.

5. Other Organic Layer (1) First Organic Layer A hole injection layer, a hole transport layer, an organic semiconductor layer, or the like can be provided as the first organic layer between the anode and the first light emitting layer. The hole injection layer or the hole transport layer is a layer that assists hole injection into the light emitting layer and transports it to the light emitting region, and has a high hole mobility and a low ionization energy of usually 5.5 eV or less. The hole injection layer is provided to adjust the energy level, for example, to alleviate a sudden change in the energy level. As such a hole injection layer or a hole transport layer, a material that transports holes to the light emitting layer with a lower electric field strength is preferable, and an electric field having a hole mobility of, for example, 10 ⁴ to 10 ⁶ V / cm. It is preferably at least 10 ⁻⁶ cm ² / V · second or more when applied. The material for forming the hole injecting layer or the hole transporting layer is not particularly limited as long as it has the above-mentioned preferred properties, and conventionally used as a charge transporting material for holes in photoconductive materials, Any of known materials used for the hole injection layer of organic EL devices can be selected and used.

  Specific examples of the material for forming such a hole injection layer or a hole transport layer include, for example, triazole derivatives (see US Pat. No. 3,112,197, etc.), oxadiazole derivatives (US Pat. No. 3, 189,447, etc.), imidazole derivatives (see JP-B-37-16096, etc.), polyarylalkane derivatives (US Pat. Nos. 3,615,402, 3,820,989) No. 3,542,544, JP-B-45-555, JP-A-51-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, No. 55-108667, No. 55-156953, No. 56-36656, etc.), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,1) No. 0,729, No. 4,278,746, JP-A-55-88064, JP-A-55-88065, JP-A-49-105537, JP-A-55-51086, JP-A-56. No.-80051, No. 56-88141, No. 57-45545, No. 54-112737, No. 55-74546, etc.), Phenylenediamine derivatives (US Pat. No. 3,615,404) , Japanese Patent Publication Nos. 51-10105, 46-3712, 47-25336, JP 54-53435, 54-110536, 54-1119925, etc.) Arylamine derivatives (US Pat. Nos. 3,567,450, 3,180,703, 3,240,597, No. 3,658,520, No. 4,232,103, No. 4,175,961, No. 4,012,376, JP-B-49-35702 39-27577, JP-A 55-144250, 56-119132, 56-22437, West German Patent 1,110,518, etc.), amino-substituted chalcone derivatives (See US Pat. No. 3,526,501, etc.), oxazole derivatives (disclosed in US Pat. No. 3,257,203 etc.), styryl anthracene derivatives (Japanese Patent Laid-Open No. 56-46234, etc.) ), Fluorenone derivatives (see JP-A-54-110837, etc.), hydrazone derivatives (US Pat. No. 3,717,462, JP-A-54-59143) Gazette, 55-52063 gazette, 55-52064 gazette, 55-46760 gazette, 55-85495 gazette, 57-11350 gazette, 57-14749 gazette, JP-A-2-311591 Stilbene derivatives (Japanese Patent Laid-Open Nos. 61-210363, 61-228451, 61-14642, 61-72255, 62-47646, 62-36674). No. 62-10652, No. 62-30255, No. 60-93455, No. 60-94462, No. 60-174749, No. 60-175052), silazane derivatives (US Pat. No. 4,950,950), polysilane (JP-A-2-204996), aniline Polymer (JP-A-2-282263), an electroconductive oligomer (particularly a thiophene oligomer) disclosed in JP-A-1-211399 and the like.

  As the material for the hole injection layer or the hole transport layer, the above-mentioned materials can be used. Porphyrin compounds (disclosed in JP-A No. 63-295965) and aromatic tertiary amine compounds And styrylamine compounds (US Pat. No. 4,127,412, JP-A-53-27033, 54-58445, 54-149634, 54-64299, 55- 79450 publication, 55-144250 publication, 56-119132 publication, 61-295558 publication, 61-98353 publication, 63-295695 publication etc.), aromatic tertiary amine compounds It can also be used. Further, for example, 4,4′-bis (N- (1-naphthyl) -N-phenylamino) biphenyl having two condensed aromatic rings described in US Pat. No. 5,061,569 in the molecule. 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) -N— in which three triphenylamine units described in JP-A-4-308688 are linked in a starburst type. And phenylamino) triphenylamine. Furthermore, in addition to the above-mentioned aromatic dimethylidin compounds shown as the material for the light emitting layer, inorganic compounds such as p-type Si and p-type SiC can also be used as the material for the hole injection layer or the hole transport layer.

The hole transport material is preferably the aromatic amine derivative represented by the following general formula (1).
[Wherein, L ₁ is a substituted or unsubstituted divalent group having 5 to 60 carbon atoms, an arylene group or a heterocyclic group, and Ar _{7 to} Ar ₁₀ are each a substituted or unsubstituted nuclear atom having 5 to 5 atoms. 50 substituents or substituents represented by the following general formula.
(In the formula, L ₂ is a divalent group consisting of a substituted or unsubstituted arylene group or heterocyclic group having 5 to 60 carbon atoms, and Ar _{11 to} Ar ₁₂ are each a substituted or unsubstituted nuclear atom number of 5 to 5. 50 substituents.)]

Examples of L ₁ and L ₂ include biphenylene, terphenylene, phenanthrene, and fluorenylene, preferably biphenylene and terphenylene, and more preferably biphenylene.

Examples of Ar _{7 to} Ar ₁₂ include a biphenyl group, a terphenyl group, a phenanthrene group, a fluorenyl group, a 1-naphthyl group, a 2-naphthyl group, and a phenyl group, and preferably a biphenyl group, a terphenyl group, a 1-naphthyl group, or It is a phenyl group.

In the compound represented by the general formula (1), Ar _{7 to} Ar ₁₀ are preferably the same substituent. At this _time, Ar 7 _{to Ar 10} is preferably a biphenyl group, a terphenyl group, more preferably a biphenyl group.

Moreover, it is preferable that Ar < ₈ > -Ar < ₁₀ > is the same substituent among the substituents of Ar < ₇ > -Ar < ₁₀ > as for the compound represented by the said General formula (1). At that time, Ar _{8 to} Ar ₁₀ are preferably a biphenyl group or a terphenyl group, more preferably a biphenyl group, and Ar ₇ is preferably a biphenyl group, a terphenyl group, a phenanthrene group, a fluorenyl group, or a 1-naphthyl group. 2-naphthyl group or phenyl group, more preferably biphenyl group, terphenyl group, 1-naphthyl group or phenyl group. More preferably, Ar _{8 to} Ar ₁₀ are biphenyl, and Ar ₇ is a terphenyl group or a 1-naphthyl group.

Moreover, it is preferable that the compound represented by the said General formula (1) is a substituent from which three or more among the substituents of Ar < ₇ > -Ar < ₁₀ > differ. Ar _{7 to} Ar ₁₂ are preferably a biphenyl group, a terphenyl group, a phenanthrene group, a fluorenyl group, a 1-naphthyl group, a 2-naphthyl group, or a phenyl group, more preferably a biphenyl group, a terphenyl group, or 1-naphthyl. Group or phenyl group. More preferably, Ar _{9 to} Ar ₁₀ are biphenyl, Ar ₇ is a terphenyl group and 1-naphthyl group, and Ar ₈ is a phenyl group.

As the hole injection layer, a compound represented by the following formula can be used.
(Wherein R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ are substituted or unsubstituted alkyl groups, substituted or unsubstituted aryl groups, substituted or unsubstituted aralkyl groups, or substituted or unsubstituted A substituted heterocyclic group, provided that R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ may be the same or different, and R ₁ and R ₂ , R ₃ and R ₄ , R ₅ and R ₆ , or R ₁ and R ₆ , R ₂ and R ₃ , and R ₄ and R ₅ may form a condensed ring.)

More preferable are the following compounds.

  This hole injection layer or hole transport layer may be composed of one or more layers made of the above-mentioned materials, or from a compound different from the hole injection layer or hole transport layer. It may be a laminate of a hole injection layer or a hole transport layer. Although the film thickness of a positive hole injection layer or a positive hole transport layer is not specifically limited, Preferably, it is 20-200 nm.

The organic semiconductor layer is a layer that assists hole injection or electron injection into the light emitting layer, and preferably has a conductivity of 10 ⁻¹⁰ S / cm or more. As a material of such an organic semiconductor layer, a conductive oligomer such as a thiophene-containing oligomer or an arylamine oligomer described in JP-A-8-193191, a conductive dendrimer such as an arylamine dendrimer, or the like can be used. . Although the film thickness of an organic-semiconductor layer is not specifically limited, Preferably, it is 10-1,000 nm.

(2) Second organic layer An electron injection layer, an electron transport layer, or the like can be provided as the second organic layer between the cathode and the second light emitting layer. The electron injection layer or the electron transport layer is a layer that assists the injection of electrons into the light emitting layer, and has a high electron mobility. The electron injection layer is provided to adjust the energy level, for example, to ease a sudden change in the energy level. As a material used for the electron injection layer or the electron transport layer, 8-hydroxyquinoline or a metal complex of a derivative thereof, an oxadiazole derivative, or a nitrogen-containing heterocyclic derivative is preferable. As a specific example of the metal complex of 8-hydroxyquinoline or a derivative thereof, a metal chelate oxinoid compound containing a chelate of oxine (generally 8-quinolinol or 8-hydroxyquinoline), for example, tris (8-quinolinol) aluminum is used. Can do. And as an oxadiazole derivative, the following formula
(In the formula, Ar ⁵⁰ , Ar ⁵¹ , Ar ⁵² , Ar ⁵⁴ , Ar ⁵⁵ and Ar ⁵⁸ each represent an aryl group with or without a substituent, Ar ⁵⁰ and Ar ⁵¹ , Ar ⁵² and Ar ⁵⁴ , Ar ^55. And Ar ⁵⁸ may be the same or different, Ar ⁵³ , Ar ⁵⁶ and Ar ⁵⁷ each represent an arylene group with or without a substituent, and Ar ⁵⁶ and Ar ⁵⁷ may be the same or different. And an electron transfer compound represented by: Examples of the aryl group in these formulas include a phenyl group, a biphenyl group, an anthranyl group, a perylenyl group, and a pyrenyl group. Examples of the arylene group include a phenylene group, a naphthylene group, a biphenylene group, an anthranylene group, a peryleneylene group, and a pyrenylene group. And as a substituent to these, a C1-C10 alkyl group, a C1-C10 alkoxy group, a cyano group, etc. are mentioned. As this electron transfer compound, those having good thin film forming properties are preferably used. Specific examples of these electron transfer compounds include the following.

  Examples of the nitrogen-containing heterocyclic derivative include nitrogen-containing compounds that are not metal complexes and include the structures shown in the following (a) to (c).

(A) = 5- or 6-membered ring containing N-skeleton

(B)
(In the formula, X represents a carbon atom or a nitrogen atom. Z ₁ and Z ₂ each independently represents an atomic group capable of forming a nitrogen-containing heterocycle.)

(C)
In addition, as the nitrogen-containing heterocyclic derivative, an organic compound having a skeleton having a nitrogen-containing aromatic polycyclic group composed of a 5-membered ring or a 6-membered ring and having a non-adjacent bond position in the case of containing a plurality of nitrogen atoms Can be mentioned. In the case of such a nitrogen-containing aromatic polycyclic group having a plurality of nitrogen atoms, examples thereof include nitrogen-containing aromatic polycyclic organic compounds having a skeleton obtained by combining the above (a) and (b) or (a) and (c). .

Furthermore, examples of the nitrogen-containing heterocyclic derivative include the compounds shown in the following (d) to (g).
(D) A nitrogen-containing heterocyclic derivative containing a nitrogen-containing heterocyclic group selected from the following formulae.
(In the formula, R is an aryl group having 6 to 40 carbon atoms, a heteroaryl group having 3 to 40 carbon atoms, an alkyl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms, and n is 0 to 0. And when n is an integer of 2 or more, the plurality of R may be the same or different from each other.)

(E) Furthermore, as a preferable specific compound, a nitrogen-containing heterocyclic derivative represented by the following formula:

HAr-L-Ar ⁶¹ -Ar ⁶²

(In the formula, HAr is a nitrogen-containing heterocycle having 3 to 40 carbon atoms which may have a substituent, and L is a single bond or arylene having 6 to 40 carbon atoms which may have a substituent. A heteroarylene group having 3 to 40 carbon atoms which may have a group or a substituent, and Ar ⁶¹ is a divalent aromatic hydrocarbon group having 6 to 40 carbon atoms which may have a substituent. And Ar ⁶² is an aryl group having 6 to 40 carbon atoms which may have a substituent or a heteroaryl group having 3 to 40 carbon atoms which may have a substituent.

The following groups are exemplified as HAr.

Examples of L include the following groups.

Examples of Ar ⁶² include the following groups.

Examples of Ar ⁶¹ include the following groups.
(In the formula, R ^{61 to} R ⁷⁴ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 40 carbon atoms, An aryl group having 6 to 40 carbon atoms or a heteroaryl group having 3 to 40 carbon atoms which may have a substituent, and Ar ⁶³ each having 6 to 40 carbon atoms which may have a substituent. An aryl group or a heteroaryl group having 3 to 40 carbon atoms.)
Preferably, R ^{61 to} R ⁷⁴ are all hydrogen atoms.

(F) The following compounds described in JP-A-9-3448
Wherein R ^{81 to} R ⁸⁴ are each independently a hydrogen atom, a substituted or unsubstituted aliphatic group, a substituted or unsubstituted aliphatic cyclic group, a substituted or unsubstituted carbocyclic aromatic ring group. Represents a substituted or unsubstituted heterocyclic group, and X ⁸¹ and X ⁸² each independently represents an oxygen atom, a sulfur atom or a dicyanomethylene group.)

(G) The following compound described in JP-A-2000-173774
[In the formula, R ⁹¹ , R ⁹² , R ⁹³ and R ⁹⁴ are the same or different groups, and are aryl groups represented by the following formulae.
(Wherein R ⁹⁵ , R ⁹⁶ , R ⁹⁷ , R ⁹⁸ and R ⁹⁹ are the same or different from each other, and a hydrogen atom or at least one of them is a saturated or unsaturated alkoxyl group, an alkyl group, an amino group Or an alkylamino group.)]

(H) Furthermore, it may be a polymer compound containing the nitrogen-containing heterocyclic group or nitrogen-containing heterocyclic derivative.

  Although the film thickness of an electron injection layer or an electron carrying layer is not specifically limited, Preferably, it is 1-100 nm.

It is preferable that the 1st light emitting layer or 1st organic layer which is an organic layer nearest to an anode contains the oxidizing agent. Preferred oxidizing agents are electron withdrawing or electron acceptors. The electron-withdrawing or electron acceptor is preferably an organic compound having an electron-withdrawing substituent or an electron-deficient ring.
Examples of the electron-withdrawing substituent include halogen, CN-, carbonyl group, arylboron group and the like.
Examples of electron-deficient rings include 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-quinolyl, 3-quinolyl, 4-quinolyl, 2-imidazole, 4-imidazole, 3-pyrazole, 4-pyrazole, pyridazine, and pyrimidine. , Pyrazine, cinnoline, phthalazine, quinazoline, quinoxaline, 3- (1,2,4-N) -triazolyl, 5- (1,2,4-N) -triazolyl, 5-tetrazolyl, 4- (1-O, 3-N) -oxazole, 5- (1-O, 3-N) -oxazole, 4- (1-S, 3-N) -thiazole, 5- (1-S, 3-N) -thiazole, 2 A compound selected from the group consisting of -benzoxazole, 2-benzothiazole, 4- (1,2,3-N) -benzotriazole, and benzimidazole, Not be limited to these.
Preferred are Lewis acids, various quinone derivatives, dicyanoquinodimethane derivatives, and salts formed with aromatic amines and Lewis acids.
More preferred are quinoid derivatives, and compounds represented by the following formulas (1a) to (1i) are exemplified. More preferred are compounds represented by (1a) and (1b).

In formulas (1a) to (1i), R ^{1 to} R ⁴⁸ are each hydrogen, halogen, a fluoroalkyl group, a cyano group, an alkoxy group, an alkyl group, or an aryl group. Preferably, they are hydrogen and a cyano group.
In the formulas (1a) to (1i), X ^{1 to} X ¹⁷ are electron-withdrawing groups and each independently has any of the structures of the following formulas (j) to (p). A structure of (j), (k), (l) is preferable.
^(Wherein, R 49 ^{to R 52} each represent hydrogen, a fluoroalkyl group, an alkyl group, an aryl group or a ^{heterocyclic, R 50} and ^{R 51} may form a ring.)
In formulas (1a) to (1i), Y ^{1 to} Y ²⁸ are each independently —N═ or —CH═.

As the halogens R ^{1 to} R ⁴⁸ , fluorine and chlorine are preferable.
As the fluoroalkyl group for R ^{1 to} R ^48, a trifluoromethyl group and a pentafluoroethyl group are preferable.
As the alkoxyl group of R ^{1 to} R ⁴⁸ , a methoxy group, an ethoxy group, an iso-propoxy group, and a tert-butoxy group are preferable.
As the alkyl group for R ^{1 to} R ⁴⁸ , a methyl group, an ethyl group, a propyl group, an iso-propyl group, a tert-butyl group, and a cyclohexyl group are preferable.
As the aryl group for R ^{1 to} R ⁴⁸ , a phenyl group and a naphthyl group are preferable.
The fluoroalkyl group, alkyl group, and aryl group of R ^{49 to} R ⁵² are the same as R ^{1 to} R ⁴⁸ .

As the heterocycle of R ^{49 to} R ⁵² , substituents represented by the following formulas are preferable.

When R ⁵⁰ and R ⁵¹ form a ring, X is preferably a substituent represented by the following formula.
(In the formula, R ^{51 ′} and R ^{52 ′} are a methyl group, an ethyl group, a propyl group, and a tert-butyl group, respectively.)

Specific examples of the quinoid derivative include the following compounds.
It is preferable that the 2nd light emitting layer or 2nd organic layer which is an organic layer nearest to a cathode contains the reducing agent. Preferred reducing agents are alkali metals, alkaline earth metals, alkali metal oxides, alkaline earth oxides, rare earth oxides, alkali metal halides, alkaline earth halides, rare earth halides, alkali metals and aromatic compounds. It is a complex formed. Particularly preferred alkali metals are Cs, Li, Na, and K.

In the present invention, the hole transport layer (hole injection layer) is preferably formed using the same material as the above-described charge barrier layer. Thereby, the kind of material used when manufacturing an organic EL element can be reduced, and it becomes advantageous in cost in industrial production.
[Example]

The compounds used in Examples and Comparative Examples are shown below.

Table 1 shows the energy gap (Eg), ionization potential (Ip), and affinity level (Af) of the above compounds.

The measuring method of the characteristic of a compound is as follows.
(1) Energy gap (Eg)
Using an ultraviolet / visible spectrophotometer (manufactured by Shimadzu, UV-3100PC), the ultraviolet-visible light absorption spectrum of the material solution (solvent: toluene) is measured, and the optical band cap calculated from the long wavelength side tangent is used as the energy. It was set as a gap (Eg).

(2) Ionization potential (Ip)
Measurement was performed using an atmospheric photoelectron spectrometer (AC-1 manufactured by Riken Keiki Co., Ltd.). The photoelectrons emitted were plotted with respect to the energy of ultraviolet rays irradiated to the material (powder) by a power of 1/2, and the threshold value of the photoelectron emission energy was defined as the ionization potential (Ip).

(3) Affinity level (Af)
Af = IP-Eg.

(4) Drive voltage The voltage (unit: V) when energized between ITO and Al was measured so that the current density was 10 mA / cm ² .

(5) Luminous efficiency The EL spectrum when a current density of 10 mA / cm ^{2 was} applied was measured with a spectral radiance meter CS1000A (manufactured by Konica Minolta), and the luminous efficiency (unit: cd / A) was calculated.

(6) CIE1931 Chromaticity current density 10 mA / cm ² is applied when the CIE1931 chromaticity EL spectra with a spectral radiance meter CS1000A (manufactured by Konica Minolta Co., Ltd.) (x, y) were measured.

(7) External quantum yield The EL spectrum at the time of applying a current density of 10 mA / cm ² was measured with a spectral radiance meter CS1000A (manufactured by Konica Minolta) and calculated by the following formula.

Example 1
(Formation of organic EL elements)
A 25 mm × 75 mm × 1.1 mm thick glass substrate with an ITO transparent electrode (anode) (manufactured by Geomatic) (ITO film thickness 130 nm) was subjected to ultrasonic cleaning in isopropyl alcohol for 5 minutes, followed by UV ozone cleaning. 30 minutes. A glass substrate with a transparent electrode line after cleaning is mounted on a substrate holder of a vacuum deposition apparatus, and a HI film having a film thickness of 60 nm is first formed on the surface on the side where the transparent electrode line is formed so as to cover the transparent electrode. Filmed. This HI film functions as a hole injection layer. Subsequent to the formation of the HI film, an HT film having a thickness of 15 nm was formed on the HI film. This HT film functions as a hole transport layer.

Further, following the formation of the HT film, RH (Eg: 2.4 eV) and RD are vapor-deposited at a film thickness of 5 nm so that the RD is 0.5% by weight. (Ip / Af (eV) = 5.6 / 3.2). The first light emitting layer emits red light. Next, an HT film (Ip / Af [eV] = 5.36 / 2.3) having a thickness of 5 nm was formed as a charge barrier layer. BH and BD are vapor-deposited on the charge barrier layer so that the BD is 7.5% by weight, and a blue light-emitting layer (second light-emitting layer) having a film thickness of 40 nm (Ip / Af [eV] = 5 .8 / 2.8). On this film, a 20-nm thick tris (8-quinolinol) aluminum film (Alq ₃ film) was formed as an electron transport layer. Thereafter, a 1.6 nm LiF film was formed as an electron injection layer. On the LiF film, metal Al was deposited to a thickness of 150 nm to form a metal cathode to form an organic EL light emitting device.

(Evaluation of organic EL elements)
FIG. 5 shows the energy levels of the first light-emitting layer, the first charge barrier layer, and the second light-emitting layer prepared in Example 1. The characteristics of the obtained organic EL light emitting device were measured. The results are shown in Table 2.

Comparative Example 1
In Example 1, an organic EL light emitting element was formed in the same manner as in Example 1 except that the charge blocking layer was not formed after the first light emitting layer was formed. The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Comparative Example 2
In Comparative Example 1, the thickness of the hole transport layer was set to 10 nm, the thickness of the first light emitting layer was set to 40 nm, the thickness of the electron transport layer was set to 30 nm, and the film formation of the second light emitting layer was omitted. An organic EL light emitting device was formed in the same manner as in Example 1. The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Comparative Example 3
In Comparative Example 1, the organic EL light emitting device was the same as Comparative Example 1 except that the thickness of the hole transport layer was 20 nm, the thickness of the second light emitting layer was 40 nm, and the film formation of the first light emitting layer was omitted. Formed. The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Comparative Example 4
In Example 1, an ET film (Ip / Af [eV] = 5.71 / 2.73) was formed in a thickness of 5 nm instead of HT as a charge barrier layer in the same manner as in Example 1. An organic EL light emitting device was formed. FIG. 6 shows the energy levels of the first light-emitting layer, the first charge barrier layer, and the second light-emitting layer prepared in Comparative Example 4. The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Example 2
In Example 1, after forming the second light-emitting layer with a film thickness of 10 nm, as the third light-emitting layer, BH and GD were vapor-deposited with a film thickness of 30 nm and GD was 10% by weight to form a film ( Ip / Af [eV] = 5.8 / 2.8) and forming an organic EL light emitting device in the same manner as in Example 1 except that a green light emitting layer was formed and then an Alq ₃ layer (electron transport layer) was formed. Formed. The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Comparative Example 5
In Example 2, a CBP film (Ip / Af [eV] = 5.86 / 2.41) was formed in a thickness of 5 nm instead of HT as a charge barrier layer, as in Example 2. An organic EL light emitting device was formed. FIG. 7 shows the energy levels of the first light-emitting layer, the first charge barrier layer, and the second light-emitting layer prepared in Comparative Example 5. The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Example 3
In Example 1, instead of HT, HT and GD were deposited and deposited (Ip / Af [eV] = 5.36 / 2.3) so that GD would be 10% by weight instead of HT as the charge barrier layer. An organic EL light emitting device was formed in the same manner as in Example 1 except that the thickness of the second light emitting layer was 40 nm.
The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

Example 4
In Example 2, instead of HT, HT and GD were deposited and deposited (Ip / Af [eV] = 5.36 / 2.3) so that GD was 5 wt% instead of HT as the charge barrier layer. An organic EL light emitting device was formed in the same manner as in Example 2 except that the thicknesses of the second light emitting layer and the third light emitting layer were 15 nm and 25 nm, respectively.
The obtained organic EL light emitting device was measured in the same manner as in Example 1. The measurement results are shown in Table 2.

In Example 1, the red light emission of Comparative Example 2 and the blue light emission of Comparative Example 3 were combined. The red light emitting layer with a small energy gap is the first light emitting layer on the anode side, the blue light emitting layer with a large energy gap is the second light emitting layer, and a charge barrier layer with a small affinity level is provided between them. It was higher than the yield and good white light emission could be obtained (FIG. 5).
In Example 2, by adding a green light emitting layer as the third light emitting layer to Example 1, it was possible to obtain good white light emission with higher current efficiency while maintaining the same external quantum yield.
In Example 3, by further doping the charge blocking layer with a green light emitting material as compared with Example 1, it was possible to obtain good white light emission with an equivalent external quantum yield.

In Comparative Example 4, since an electron transporting charge barrier layer having a high affinity level was provided, the redness was further increased and the efficiency was lowered (FIG. 6).
In Comparative Example 5, since the charge barrier layer having a large ionization potential and a small affinity is provided, holes remain in the first light emitting layer, and redness is increased as compared with Example 2, and good white light emission can be obtained. None (Figure 7).

In Comparative Example 1, the CIE 1931 chromaticity (x, y) is far away from the vicinity of white (0.33, 0.33) in the range of luminance of 10 to 10000 cd / m ² , and the redness is increased and is not good white. It was. In Examples 1 to 4, the chromaticity (x, y) was near white, and good white light emission could be obtained. In particular, in Example 3, the change in chromaticity (x, y) was less than that in Examples 1 and 2 and Example 4 in the luminance range of 10 to 10000 cd / m ² , and even better white light emission could be obtained ( 8 and 9).

Comparative Example 6
An organic EL device was produced in the same manner as in Example 1 except that the compositions of the first light emitting layer, the electron blocking layer, and the second light emitting layer were changed as shown in Table 3. That is, the cathode side of the charge barrier layer is a red light emitting layer. An amine hole transport material (GD) having Af of about 3.1 eV was used as the charge barrier layer. The obtained organic EL light emitting device was measured in the same manner as in Example 1. Table 3 shows the measurement results.
(CIEx, CIEy) = (0.657, 0.340) and only the red color of the second light emitting layer was illuminated. Also, the luminous efficiency was poor.

Comparative Example 7
An organic EL device was produced in the same manner as in Example 1 except that the compositions of the first light emitting layer and the second light emitting layer were changed as shown in Table 3. That is, the cathode side of the charge barrier layer is a red light emitting layer as in the comparative example 6. Here, the Af of the host of the first light emitting layer is made higher than the Af of the charge barrier layer. The obtained organic EL light emitting device was measured in the same manner as in Example 1. Table 3 shows the measurement results.
(CIEx, CIEy) = (0.657, 0.340), only the red color of the second light emitting layer was lit, and the efficiency was poor. Also in this case, the light emission is only red, and electrons are not injected into the first light emitting layer (blue), and a good white color is not obtained.
Thus, from the above two comparative examples, when the Eg of the host of the second light emitting layer is smaller than the Eg of the host of the first light emitting layer, the light emission balance cannot be achieved no matter how the Af level of the charge barrier layer is devised. I understand that.
Therefore, the Eg of the second light emitting layer needs to be larger than the Eg of the first light emitting layer.

Comparative Example 8
An organic EL device was produced in the same manner as in Example 1 except that the compositions of the first light emitting layer, the electron blocking layer, and the second light emitting layer were changed as shown in Table 3. That is, the first light emitting layer was green and the second light emitting layer was blue. The charge barrier layer was doped with red (RD). The obtained organic EL light emitting device was measured in the same manner as in Example 1. Table 3 shows the measurement results.
According to the chromaticity data, the energy recombined at the interface between the charge barrier layer and the second light emitting layer moves from the blue dopant to the red dopant to emit light, but since the energy does not move from red to green, almost no green light is seen. I found out that there wasn't.

Comparative Example 9
An organic EL device was produced in the same manner as in Example 1 except that the compositions of the first light emitting layer, the electron blocking layer, and the second light emitting layer were changed as shown in Table 3. That is, the first light emitting layer was blue, the second light emitting layer was red, and the charge barrier layer was doped with green. The obtained organic EL light emitting device was measured in the same manner as in Example 1. Table 3 shows the measurement results.
As shown in the chromaticity data, the emission was almost red.

As shown in Example 3 and Comparative Examples 8 and 9, in order to form a well-balanced three-wavelength white color, it is preferable to arrange blue, which emits less light, in the region where it is most recombined. Therefore, blue becomes the second light emitting layer. From the balance of the host material, red is arranged in the first light emitting layer. This configuration provides a well-balanced white color.
Furthermore, when the charge barrier layer is doped with green, green can be emitted by exciton energy generated in the interface region between the charge barrier layer and the second light emitting layer. Further, since the charge barrier layer constituting the recombination region is doped with green at the interface with the first and second light emitting layers, the green light emission is stabilized. Green, which is highly visible, can be easily seen by human eyes when the light emission balance is lost. Therefore, by arranging green at the position where the balance is most balanced, it is possible to obtain white with little color shift.

Example 5
An organic EL device was produced in the same manner as in Example 2 except that the compositions of the second light emitting layer and the third light emitting layer were changed as shown in Table 3. The obtained organic EL light emitting device was measured in the same manner as in Example 1. Table 3 shows the measurement results.
As shown in the chromaticity data, blue light emission at around 460 nm was weak, and suitable white light emission was not achieved. The cause is that although recombination occurs near the charge barrier layer / second light emitting layer (green) interface and emits green light, it is difficult to transfer energy to the blue light emitting layer, so that blue light emission is weakened.

  As can be seen from the comparison between Example 2 and Example 5, in Example 2, the recombination energy in the second light-emitting layer is moved to the third light-emitting layer to emit green light in the third light-emitting layer. In Example 2, since green is arranged on the cathode side with respect to blue, it is possible to balance electron injection with respect to blue. This is because the green dopant becomes an electron trap. Thereby, it is possible to realize a white element configuration that is balanced as a whole.

Example 6
(Full color light emitting device)
On a support substrate of 112 mm × 143 mm × 1.1 mm (OA2 glass: manufactured by Nippon Electric Glass Co., Ltd.) V259BK (manufactured by NS The film was exposed to ultraviolet rays through a photomask so as to form a pattern, developed with a 2% aqueous sodium carbonate solution, and baked at 200 ° C. to form a black matrix (film thickness: 1.5 μm) pattern.

  Next, as a blue color filter material, V259B (manufactured by Nippon Steel Chemical Co., Ltd.) is spin-coated and aligned with the BM through a photomask that can obtain 320 rectangular patterns (100 μm line, 230 μm gap). The film was exposed to ultraviolet light, developed with a 2% aqueous sodium carbonate solution, and baked at 200 ° C. to form a pattern of a blue color filter (film thickness: 1.5 μm).

  Next, as a green color filter material, V259G (manufactured by Nippon Steel Chemical Co., Ltd.) is spin-coated, and aligned with the BM through a photomask that can obtain 320 rectangular patterns (100 μm line, 230 μm gap). The film was exposed to ultraviolet light, developed with a 2% aqueous sodium carbonate solution, and baked at 200 ° C. to form a pattern of a green color filter (film thickness: 1.5 μm) adjacent to the blue color filter.

  Next, CRY-S840B (manufactured by Fuji Film Arch) is spin-coated as a material for the red color filter, and is applied to the BM through a photomask that can obtain 320 rectangular patterns (100 μm line, 230 μm gap). Alignment, UV exposure, development with 2% aqueous sodium carbonate solution, baking at 200 ° C. to form a red color filter (1.5 μm thick) pattern between the blue and green color filters did.

Next, an acrylic thermosetting resin (V259PH: manufactured by Nippon Steel Chemical Co., Ltd.) was spin-coated on the previous substrate as a planarizing film, and baked at 180 ° C. to form a planarizing film (film thickness 5 μm).
Next, ITO (indium tin oxide) was formed into a film with a thickness of 130 nm by sputtering.

  Next, a positive resist (HPR204: manufactured by Fuji Orin) is spin-coated on this substrate, and UV exposure is performed through a cathode extraction portion and a photomask that forms a stripe pattern with a 90 μm line and a 20 μm gap. The resist pattern was developed with a developer of tetramethylammonium hydroxide and baked at 130 ° C.

  Next, the exposed ITO was etched with an ITO etchant. Next, the resist is treated with a stripping solution containing ethanolamine as a main component (N303: manufactured by Nagase Sangyo Co., Ltd.), and an ITO pattern (lower electrode: lower electrode: on the blue color filter, green color filter, and red color filter) Anode, 960 lines).

  Next, a negative resist (V259PA: manufactured by Nippon Steel Chemical Co., Ltd.) was spin-coated as a first interlayer insulating film, exposed to ultraviolet rays through a photomask, and developed with a developer of tetramethylammonium hydroxide. Next, baking was performed at 180 ° C., and an ITO opening covering the edge of ITO was 70 μm × 290 μm) to form a lattice-patterned interlayer insulating film.

Next, as a second interlayer insulating film (partition), a negative resist (ZPN1100: manufactured by Nippon Zeon) is spin-coated, and after ultraviolet exposure through a photomask that forms a stripe pattern with a 20 μm line and a 310 μm gap, Further, post-exposure baking was performed. Next, the negative resist was developed with a developer of tetramethylammonium hydroxide to form a second interlayer insulating film (partition wall) orthogonal to the ITO stripe.
The substrate thus obtained was subjected to ultrasonic cleaning in pure water and isopropyl alcohol, dried by air blow, and then UV cleaned.

  Thereafter, the organic layer (from the hole injection layer to the electron injection layer) was mask-deposited in a range covering the color filter, and the cathode was further subjected to mask deposition so that it could be connected to the previously formed ITO take-out electrode. The cathode (upper electrode) was automatically separated by the partition wall previously formed on the substrate, and had a pattern (240 lines) intersecting with the lower electrode.

  After the organic EL device is fabricated on the substrate, the substrate is moved to a dry box in which dry nitrogen is circulated so that the substrate is not exposed to the atmosphere, and the display portion is covered with the blue plate glass of the sealing substrate in the dry box. The peripheral part of the part was photocured with a cationic curable adhesive (TB3102: manufactured by ThreeBond) and sealed.

  In this way, a full-color light emitting device in which the lower electrode and the upper electrode form an XY matrix is manufactured, and a DC voltage is applied to the lower electrode and the upper electrode (lower electrode: (+), upper electrode: (-) ), The intersection (pixel) of each electrode emitted light.

(Characteristic evaluation of full-color light emitting device)
(1) Blue performance When a DC voltage of 7.25 V was applied between the lower electrode and the upper transparent electrode corresponding to the blue color filter, blue light was emitted. When measured with a spectral radiance meter CS-1000 (manufactured by Minolta), the luminance was 31 cd / m ² and the chromaticity (0.124, 0.117). When the value of the current flowing between the two electrodes was measured and the luminous efficiency was calculated, it was 1.14 cd / A.

(2) Green performance When a DC voltage of 7.25 V was applied between the lower electrode corresponding to the green color filter and the upper transparent electrode, the green light was emitted. When measured with a spectral radiance meter CS-1000 (manufactured by Minolta), the luminance was 250 cd / m ² and the chromaticity (0.247, 0.621). When the value of the current flowing between the two electrodes was measured and the luminous efficiency was calculated, it was 9.24 cd / A.

(3) Red performance When a DC voltage of 7.25 V was applied between the lower electrode and the upper transparent electrode corresponding to the red color filter, red light was emitted. When measured with a spectral radiance meter CS-1000 (manufactured by Minolta), the luminance was 85 cd / m ² and the chromaticity (0.652, 0.335). The value of the current flowing between the two electrodes was measured and the luminous efficiency was calculated to be 3.15 cd / A.

(4) Full lighting When white voltage was emitted when a DC voltage of 7.25 V was applied between all lower electrodes and upper transparent electrodes. When measured with a spectral radiance meter CS-1000 (manufactured by Minolta), the luminance was 451 cd / m ² and the chromaticity (0.324, 0.397). When the value of the current flowing between the two electrodes was measured and the luminous efficiency was calculated, it was 4.51 cd / A, which was very high efficiency.

  The organic EL device of the present invention can be used for various display devices, backlights, full-color display devices using color filters, light sources for general illumination and special illumination.

Claims (21)

An anode, a first light emitting layer, a charge barrier layer, a second light emitting layer, and a cathode are laminated in this order,
The first light emitting layer and the second light emitting layer each contain a host material and a dopant,
The energy gap of the host material of the first light emitting layer is smaller than the energy gap of the host material of the second light emitting layer;
The host material of the first light emitting layer is a hole transporting material, the host material of the second light emitting layer is an electron transporting material,
The affinity level of the charge barrier layer is 0.2 eV or more smaller than the affinity level of the host material of the second light emitting layer,
An organic electroluminescence device in which an ionization potential (Ie1) of the charge barrier layer and an ionization potential (Ih1) of a host material of the first light emitting layer satisfy the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1) An anode, a first light-emitting layer, a charge barrier layer, a second light-emitting layer, a third light-emitting layer and a cathode are laminated in this order,
The first light emitting layer, the second light emitting layer, and the third light emitting layer each contain a host material and a dopant,
The energy gap of the host material of the first light emitting layer is smaller than the energy gap of the host material of the second light emitting layer;
The host material of the first light emitting layer is a hole transporting material;
The host material of the second light emitting layer and the third light emitting layer is an electron transporting material,
The charge barrier layer is a hole transporting material;
An organic electroluminescence device in which the ionization potential (Ie1) of the charge barrier layer and the ionization potential (Ih1) of the host material of the first light emitting layer satisfy the following relationship (1).
Ie1 <Ih1 + 0.1 (eV) (1)   The organic electroluminescence device according to claim 2, wherein the affinity level of the charge barrier layer is 0.2 eV or less smaller than the affinity level of the host material of the second light emitting layer.   The organic electroluminescent element according to claim 1, wherein the energy gap of the host material of the first light emitting layer is 0.4 eV or less smaller than the energy gap of the host material of the second light emitting layer.   The organic electroluminescence device according to claim 1, wherein the dopant of the first light emitting layer is a red dopant, and the dopant of the second light emitting layer is a blue dopant.   The organic electroluminescent device according to claim 2 or 3, wherein the dopant of the first light emitting layer is a red dopant, the dopant of the second light emitting layer is a blue dopant, and the dopant of the third light emitting layer is a green dopant. .   The organic electroluminescent element according to claim 1, wherein the charge barrier layer contains a light emitting material.   The organic electroluminescent device according to claim 7, wherein the light emitting material of the charge barrier layer is a green dopant.   The organic electroluminescent element according to claim 1, further comprising a hole transport layer adjacent to the first light emitting layer between the anode and the first light emitting layer.   The organic electroluminescence device according to claim 9, wherein the material forming the hole transport layer and the material forming the charge barrier layer are the same material.   The first light-emitting layer or the first organic layer that is an organic layer close to the anode contains an oxidizing agent, and / or the second light-emitting layer or the second organic layer that is an organic layer close to the cathode is reduced. The organic electroluminescent element as described in any one of Claims 1-10 containing the agent. The host material of the first light emitting layer is a compound represented by the following formula (1), and the dopant of the first light emitting layer is a compound having a fluoranthene skeleton or a perylene skeleton. The organic electroluminescent element of description.
X- (Y) n (1)
(Wherein X is a condensed aromatic ring group having 3 or more carbon rings,
Y is a group selected from a substituted or unsubstituted aryl group, a substituted or unsubstituted diarylamino group, a substituted or unsubstituted arylalkyl group, or a substituted or unsubstituted alkyl group;
n is an integer of 1 to 6, and when n is 2 or more, Y may be the same or different. ) The organic electroluminescence device according to claim 12, wherein the compound having the fluoranthene skeleton or the perylene skeleton is an indenoperylene derivative represented by the following formula (2) or (3).
(In the formula, Ar ¹ , Ar ² and Ar ³ are each a substituted or unsubstituted aromatic ring group or a substituted or unsubstituted aromatic heterocyclic group, and X ^{1 to} X ¹⁸ are hydrogen, halogen and alkyl, respectively. Group, alkoxy group, alkylthio group, alkenyl group, alkenyloxy group, alkenylthio group, aromatic ring-containing alkyl group, aromatic ring-containing alkyloxy group, aromatic ring-containing alkylthio group, aromatic ring group, aromatic heterocyclic group, aromatic ring Oxy group, aromatic ring thio group, aromatic alkenyl group, alkenyl aromatic ring group, amino group, carbazolyl group, cyano group, hydroxyl group, -COOR ^{1 ′} (R ^{1 ′} is hydrogen, alkyl group, alkenyl group, aromatic ring-containing alkyl is a group or an aromatic ring ^{group), -. COR 2 '(} R 2' is hydrogen, an alkyl group, an alkenyl group, an aromatic ring-containing alkyl group, aromatic ring group or amino In a), or -OCOR ^{3 '(R 3'} is adjacent group ^.X 1 ^{to X 18} is an alkyl group, an alkenyl group, an aromatic ring-containing alkyl group or aromatic ring group) is bonded to each other Or may form a ring together with the substituted carbon atom.)   The organic electroluminescence device according to claim 13, wherein the indenoperylene derivative is a dibenzotetraphenyl perifuranthene derivative.   The organic electroluminescence according to any one of claims 12 to 14, wherein the host material of the first light emitting layer has 4 or more condensed rings and the host material of the second light emitting layer has 3 or less condensed rings. element. The organic electroluminescence device according to any one of claims 12 to 15, wherein the compound represented by the formula (1) is a naphthacene derivative represented by the following formula (4).
(In Formula (4), Q ^{1 to} Q ¹² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a substituted or unsubstituted aryl group having 6 to 20 nuclear carbon atoms, Amino group, substituted or unsubstituted alkoxy group having 1 to 20 carbon atoms, substituted or unsubstituted alkylthio group having 1 to 20 carbon atoms, substituted or unsubstituted aryloxy group having 6 to 20 nuclear carbon atoms, substituted or unsubstituted An arylthio group having 6 to 20 nuclear carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, a substituted or unsubstituted aralkyl group having 7 to 20 carbon atoms, or a substituted or unsubstituted 5 to 5 nuclear atoms. Represents 20 heterocyclic groups, which may be the same or different.) The organic electroluminescent device according to claim 16, wherein at least one of Q ¹ , Q ² , Q ³ and Q ^{4 in} the naphthacene derivative represented by the formula (4) is an aryl group. The organic electroluminescence device according to claim 17, wherein the naphthacene derivative represented by the formula (4) is represented by the following formula (5).
(In the formula ^{(5), Q 3 ~Q 12} , Q 101 ~Q 105, Q 201 ~Q 205 each independently represent the same group in the general formula (1) was ^Q 3 ^{to Q 12,} which are These may be the same or different, and two or more adjacent groups may be bonded to each other to form a ring.) In the naphthacene derivative represented by the formula (5), at least one of Q ¹⁰¹ , Q ¹⁰⁵ , Q ²⁰¹ and Q ²⁰⁵ is an alkyl group, an aryl group, an amino group, an alkoxy group, an aryloxy group, an alkylthio group, an arylthio group, The organic electroluminescence device according to claim 18, which is an alkenyl group, an aralkyl group or a heterocyclic group, and may be the same or different.   The organic electroluminescence device according to any one of claims 12 to 19, wherein the charge barrier layer contains a tertiary amine compound, a carbazole derivative, a compound containing a nitrogen-containing heterocyclic ring, or a metal complex. The organic electroluminescence device according to any one of claims 1 to 20, which emits white light,
A full-color light emitting device including a color filter.