Organic light-emitting device, display device, photoelectric conversion device, electronic device, lighting device, moving object, and exposure light source

Abstract

To provide an organic light-emitting element that is excellent in luminous efficacy.SOLUTION: An organic light-emitting element comprises an anode 121, a luminous layer 122, and a cathode 124 in this order. The luminous layer includes dopant material, host material, and assist material. The dopant material is a compound represented by the following formula [1]. The host material is a hydrocarbon compound. The LUMO level of the assist material is smaller than the LUMO level of the host material. In formula [1], X represents O or S. A partial structure IrLn is either one of a structure indicated in formula [2] or a structure indicated in formula [3].SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an organic light-emitting device, a display device, a photoelectric conversion device, an electronic device, a lighting device, a moving object, and an exposure light source. [Background technology]

[0002] An organic light-emitting device (also called an organic electroluminescent device or organic EL device) is an electronic device that has an anode, a cathode, and an organic compound layer disposed between these two electrodes. Holes and electrons injected from the anode and cathode recombine in the organic compound layer to generate excitons, and the organic light-emitting device emits light when these excitons return to the ground state. Recent progress in organic light-emitting devices has been remarkable, and their features include low driving voltage, a wide variety of emission wavelengths, high-speed response, and the possibility of making light-emitting devices thinner and lighter. Currently, the use of phosphorescence has been proposed as an attempt to improve the luminous efficiency of organic EL devices. Organic EL devices using phosphorescence are theoretically expected to have luminous efficiency approximately four times higher than that of fluorescent devices. Therefore, the creation of phosphorescent organometallic complexes has been actively pursued to date. This is because the creation of organometallic complexes with excellent luminous properties is important for providing high-performance organic light-emitting devices. Among the organometallic complexes that have been created so far, Patent Document 1 proposes 1-a, which is an organic light-emitting device that uses a sulfur-containing compound as a host material. Patent Document 2 proposes the following compounds 1-a and 1-b, which are organic light-emitting devices that use two types of nitrogen-containing compounds as host materials.

[0003] [ka] [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2010 / 0244004 [Patent Document 2] US Patent Application Publication No. 2020 / 0212309 Summary of the Invention [Problem to be solved by the invention]

[0005] When the iridium complexes described in Patent Documents 1 and 2 are used together with a compound having a sulfur-containing structure or a compound having a nitrogen-containing structure in the light-emitting layer of an organic light-emitting device, there are problems with the luminous efficiency and driving durability. The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an organic light-emitting device having excellent luminous efficiency, and another object of the present invention is to provide an organic light-emitting device having excellent luminous efficiency and driving durability characteristics. [Means for solving the problem]

[0006] The organic light-emitting device of the present invention comprises an anode, a light-emitting layer, and a cathode in this order, the light-emitting layer includes a dopant material, a host material, and an assist material; The dopant material is a compound represented by the following general formula [1]: the host material is a hydrocarbon compound; The LUMO level of the assist material is lower (farther from the vacuum level) than the LUMO level of the host material.

[0007] [ka] In formula [1], R1 to R 7 ,R 9 ~R 10are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group. R 8 is selected from a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and a substituted or unsubstituted phenyl group. X represents O or S. m represents an integer of 1 or more and 3 or less, and n represents an integer of 0 or more and 2 or less, with the proviso that m+n is 3. Substructure IrL n is any of the structures shown in the following general formulas [2] and [3].

[0008] [ka] In formulas [2] and [3], R 11 ~R 21 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an organic light-emitting element having high luminous efficiency and excellent driving durability. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of an embodiment of an organic light-emitting element of the present invention. [Figure 2]1A is a schematic cross-sectional view showing an example of a pixel of a display device according to one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing an example of a display device using an organic light-emitting element according to one embodiment of the present invention. [Figure 3] 1 is a schematic diagram illustrating an example of a display device according to an embodiment of the present invention. [Figure 4] 1A is a schematic diagram illustrating an example of an imaging device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating an example of an electronic device according to an embodiment of the present invention. [Figure 5] 1A is a schematic diagram illustrating an example of a display device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating an example of a foldable display device. [Figure 6] 1A is a schematic diagram showing an example of an illumination device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram showing an example of a moving body having a vehicle lamp according to an embodiment of the present invention. [Figure 7] 1A is a schematic diagram showing an example of a wearable device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram showing another example of a wearable device according to an embodiment of the present invention. [Figure 8] 1A is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating an example of an exposure light source of the image forming apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] (1) Organic light-emitting element The organic light-emitting device of the present invention comprises an anode, an emitting layer, and a cathode in this order. The emitting layer contains a dopant material, a host material, and an assist material. The dopant material is a compound represented by the following general formula [1], the host material is a hydrocarbon compound, and the LUMO level of the assist material is lower than that of the host material (farther from the vacuum level).

[0012] [ka]

[0013] In formula [1], R1 to R 10 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0014] X represents O or S. m represents an integer of 1 or more and 3 or less, and n represents an integer of 0 or more and 2 or less, with the proviso that m+n is 3. Substructure IrL n is any of the structures represented by the following general formulas [2] and [3]. Ir is iridium. When n is 2, multiple Ls may be the same or different.

[0015] [ka]

[0016] In formulas [2] and [3], R 11 ~R 21 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0017] The organic light-emitting device of the present invention will be described below with reference to the drawings. Figure 1 is a cross-sectional view showing an example of an embodiment of the organic light-emitting device of the present invention, where (a) is a diagram showing a first embodiment, (b) is a diagram showing a second embodiment, and (c) is a diagram showing a third embodiment.

[0018] The organic light-emitting element 101 in Fig. 1(a) has an anode 121, an emitting layer 122, an electron injection transport layer 123, and a cathode 124 provided in this order on a substrate 110. The organic light-emitting element 101 in Fig. 1(a) is useful when the emitting layer 122 has all of hole transport properties, electron transport properties, and emitting properties. The organic light-emitting element 101 in Fig. 1(a) is also useful when the emitting layer 122 contains a mixture of a hole transport material, an electron transport material, and a emitting material.

[0019] The organic light-emitting device 102 in Figure 1(b) is the same as the organic light-emitting device 101 in Figure 1(a), except that a hole injection transport layer 125 is provided between the anode 121 and the light-emitting layer 122. The organic light-emitting device 102 in Figure 1(b) has a layer having a carrier transport function and a layer having a light-emitting function separated from each other, and compounds having hole transport properties, electron transport properties, and light-emitting properties can be used in appropriate combinations. This greatly increases the degree of freedom in material selection, and also makes it possible to effectively confine each charge or exciton in the central light-emitting layer 122, thereby improving luminous efficiency.

[0020] The organic light-emitting device 103 in Fig. 1(c) is the same as the organic light-emitting device 102 in Fig. 1(b), except that an electron / exciton blocking layer 126 is provided between the light-emitting layer 122 and the hole injection transport layer 125. By providing the electron / exciton blocking layer 126, the organic light-emitting device 103 in Fig. 1(c) can confine electrons within the light-emitting layer 122. Therefore, similar to Fig. 1(b), it is possible to improve the luminous efficiency.

[0021] 1(a) to 1(c) are merely basic device configurations, and the present invention is not limited to these. For example, various layer configurations can be employed, such as providing an insulating layer, adhesive layer, or interference layer at the interface between the electrode and the organic compound layer, or using a hole transport layer with two layers having different HOMO levels or ionization potentials.

[0022] 1, the organic light-emitting element may have the following configurations 1 to 5. In any of the configurations, the organic compound layer always contains a light-emitting layer containing a light-emitting material. 1. (Substrate / ) Anode / Emitting layer / Cathode 2. (Substrate / ) Anode / Hole transport layer / Electron transport layer / Cathode 3. (Substrate / ) Anode / Hole transport layer / Emitting layer / Electron transport layer / Cathode (Figure 1(b)) 4. (Substrate / ) Anode / Hole injection layer / Hole transport layer / Emitting layer / Electron transport layer / Cathode 5. (Substrate / ) Anode / Hole transport layer / Emitting layer / Hole / Exciton blocking layer / Electron transport layer / Cathode

[0023] In the present invention, the mode of extraction (device configuration) of light output from the light-emitting layer may be a so-called bottom emission system in which light is extracted from the electrode on the substrate side, or a so-called top emission system in which light is extracted from the opposite side of the substrate. Also, a double-sided emission system (tandem system) in which light is extracted from both the substrate side and the opposite side of the substrate may be employed.

[0024] In the organic light-emitting device of the present invention, the iridium complex represented by general formula [1] is preferably contained in the light-emitting layer of the organic compound layer. In this case, the light-emitting layer contains at least the iridium complex represented by general formula [1], a host material, and an assist material. The compounds contained in the light-emitting layer have different uses depending on their concentration in the light-emitting layer. Specifically, they are classified into a main component and a subcomponent depending on their concentration in the light-emitting layer. The main component compound is the compound with the largest mass ratio (concentration) among the materials contained in the light-emitting layer and is also called a host material. The host material is a material that exists as a matrix around the light-emitting material in the light-emitting layer and is primarily responsible for transporting carriers to the light-emitting material and providing excitation energy to the light-emitting material. The subcomponent material is a material other than the main component and can be called a guest (dopant, light-emitting material), an assist material, or a charge injection material depending on its function. The guest, which is one type of subcomponent, is a light-emitting material that primarily emits light in the light-emitting layer. An assist material, which is a type of minor component, is a compound that helps the guest emit light and has a smaller mass ratio (content concentration) in the light-emitting layer than the host. The light-emitting assist material is also called a second host because of its function.

[0025] The concentration of the guest is preferably 0.1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and even more preferably 1% by mass or more and 15% by mass or less, based on the total amount of the constituent materials of the light-emitting layer. The iridium complex represented by general formula [1] can be said to be a compound that exhibits excellent properties at low concentrations. Furthermore, a low concentration can provide a light-emitting device with higher efficiency and color purity. Therefore, it is preferable that the guest concentration be within this range, as it can provide a light-emitting device with higher efficiency.

[0026] In the present invention, the combination of an iridium complex as a dopant material (light-emitting material) and a hydrocarbon compound as a host material (main component) contained in the light-emitting layer exhibits favorable characteristics for the following reason (1-1), and preferably further for the following reason (1-2). (1-1) Dispersibility is improved by mixing materials with similar polarities. (1-2) π-electron interactions are more likely to occur, facilitating energy transfer.

[0027] (1-1) Dispersibility is improved by mixing materials with similar polarities.

[0028] Although the ligands of the iridium complex represented by general formula [1] have a heterocyclic ring, they are slightly polar, but the aromatic rings result in a low overall polarity. Therefore, the iridium complex represented by general formula [1] has a structure in which the iridium atom is covered by a low-polarity ligand, resulting in a low overall polarity. When using this iridium complex as an emitting material, it is preferable that the host material also has a low polarity. This is because mixing materials with similar polarities improves the dispersibility of each material in the film. Generally, when polarities are significantly different, they are difficult to mix, like oil and water, but when polarities are similar, they are more compatible. Therefore, to improve dispersibility in the film, it is best to make the polarities of the materials as close as possible. The inventors have found that when using the iridium complex represented by general formula [1] as an emitting material, using a hydrocarbon compound as the host material improves the dispersibility of the emitting material in the film. This is because hydrocarbon compounds consisting only of carbon and hydrogen have extremely low polarity. When a compound containing nitrogen, oxygen, or sulfur atoms is used as a host material, a polarity difference with the carbon atom occurs, increasing the polarity of the entire molecule. When an emitting layer is formed using a highly polar host material and an iridium complex represented by general formula [1] with low polarity, intermolecular repulsion due to polarity occurs, and iridium complexes with low absolute amounts in the emitting layer tend to associate with each other. When emitting materials associate with each other, the emitting material is prone to concentration quenching, which can reduce luminous efficiency and driving durability. Therefore, a host material with low polarity is preferred, and to minimize polarity, it is preferable to design the host material molecule from carbon and hydrogen atoms. The specific content and structure of a low-polarity host material consisting of carbon and hydrogen atoms will be described later.

[0029] In order to further lower the polarity of the iridium complex represented by the general formula [1], it is useful to introduce an alkyl group into the ligand. To lower the polarity, there is also a means of expanding the π-conjugation of the ligand, that is, a method of increasing the aromatic rings, but this is accompanied by a shift to a longer emission wavelength. On the other hand, when an alkyl group is introduced into the ligand, the polarity can be lowered without significantly changing the emission wavelength of the iridium complex. Among these, it is particularly preferable that the ligand of the iridium complex has an alkyl group having 1 to 4 carbon atoms, because the polarity can be lowered while reducing the influence on the emission wavelength. By using this iridium complex as a luminescent material and the above-mentioned hydrocarbon compound as a host material, the dispersibility of the luminescent material in the film can be further improved.

[0030] (1-2) It is easy to cause π-electron interaction and energy transfer becomes easy.

[0031] Since the ligand of the iridium complex represented by the general formula [1] has a condensed ring structure with aromaticity, it is easy to cause π-electron interaction with a host material having a condensed ring structure with the same aromaticity. The π-electrons of the aromatic rings overlap with each other, making it easy for energy transfer to occur between the host material and the iridium complex. Generally, it is considered that for energy transfer from the host material to the iridium complex, it is easier for energy transfer to occur when the intermolecular distance is closer. By using a compound having a hydrocarbon condensed polycyclic structure as the host material, it becomes easier to cause π-electron interaction with the iridium complex represented by the general formula [1], which is preferable.

[0032] (2) Dopant material (iridium complex) The dopant material is a compound represented by the following general formula [1].

[0033]

Chemical formula

[0034] <R1 to R 10 >] In formula [1], R1 to R 10are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0035] Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine.

[0036] Examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a tertiary butyl group, a secondary butyl group, a 3-pentyl group, an octyl group, a cyclohexyl group, a tertiary pentyl group, a 3-methylpentan-3-yl group, a 1-adamantyl group, and a 2-adamantyl group. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms.

[0037] Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, 2-ethyl-octyloxy, and benzyloxy groups. Preferred alkoxy groups have 1 to 10 carbon atoms.

[0038] Examples of the amino group include, but are not limited to, an N-methylamino group, an N-ethylamino group, an N,N-dimethylamino group, an N,N-diethylamino group, an N-methyl-N-ethylamino group, an N-benzylamino group, an N-methyl-N-benzylamino group, an N,N-dibenzylamino group, an anilino group, an N,N-diphenylamino group, an N,N-dinaphthylamino group, an N,N-difluorenylamino group, an N-phenyl-N-tolylamino group, an N,N-ditolylamino group, an N-methyl-N-phenylamino group, an N,N-dianisolylamino group, an N-mesityl-N-phenylamino group, an N,N-dimesitylamino group, an N-phenyl-N-(4-tert-butylphenyl)amino group, an N-phenyl-N-(4-trifluoromethylphenyl)amino group, an N-piperidyl group, a carbazolyl group, and an acridyl group. The amino group is preferably an amino group having 1 to 6 carbon atoms.

[0039] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perylenyl, chrysenyl, and fluoranthenyl groups. Preferred aryl groups have 6 to 30 carbon atoms.

[0040] Examples of heterocyclic groups include, but are not limited to, pyridyl, pyrimidyl, pyrazyl, triazyl, thienyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, and phenanthrolyl groups. Preferred heterocyclic groups are those having 3 to 27 carbon atoms.

[0041] Examples of the aryloxy group include, but are not limited to, a phenoxy group and a naphthoxy group.

[0042] Examples of heteroaryloxy groups include, but are not limited to, furanyloxy groups and thienyloxy groups.

[0043] Examples of the silyl group include, but are not limited to, a trimethylsilyl group and a triphenylsilyl group.

[0044] Examples of substituents that may be further substituted by the alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, heteroaryloxy group, and silyl group include, but are not limited to, deuterium, alkyl groups such as methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, and tertiary butyl group, aralkyl groups such as benzyl group, aryl groups such as phenyl group and biphenyl group, heterocyclic groups such as pyridyl group and pyrrolyl group, amino groups such as dimethylamino group, diethylamino group, dibenzylamino group, diphenylamino group, and ditolylamino group, alkoxy groups such as methoxy group, ethoxy group, and propoxy group, aryloxy groups such as phenoxy group, halogen atoms such as fluorine, chlorine, bromine, and iodine, and cyano group.

[0045] <x> In the formula [1], X represents O or S.

[0046] <m、n> In formula [1], m represents an integer of 1 or more and 3 or less, and n represents an integer of 0 or more and 2 or less, provided that m+n is 3.

[0047] <Substructure IrL n > In formula [1], the partial structure IrL n is any of the structures represented by the following general formulas [2] and [3]. Ir is iridium. When n is 2, multiple Ls may be the same or different.

[0048] [ka]

[0049] [R 11 ~R 21 ] In formulas [2] and [3], R 11 ~R 21 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0050] R 11 ~R 21 Specific examples of the halogen atom, alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, heteroaryloxy group, and silyl group represented by the formula (I) include R1 to R2. 10 Examples of substituents that may be further substituted by the alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, heteroaryloxy group, and silyl group include, but are not limited to, R1 to R2. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms. The amino group is preferably an amino group having 1 to 6 carbon atoms. The aryl group is preferably an aryl group having 6 to 30 carbon atoms. The heterocyclic group is preferably a heterocyclic group having 3 to 27 carbon atoms. Specific examples of substituents that may be further substituted by the alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, heteroaryloxy group, and silyl group include R1 to R2. 10 Examples of the above-described examples include, but are not limited to, those described above.

[0051] In the compound represented by the general formula [1], R1 to R 21 At least one of the groups is a group other than a hydrogen atom or a deuterium atom, i.e., a halogen atom, an alkyl group, an alkoxy group, an amino group, an aryl group, a heterocyclic group, an aryloxy group, a heteroaryloxy group, a silyl group, or a cyano group, thereby reducing concentration quenching. Furthermore, these groups can provide a compound with improved sublimability during sublimation and improved solvent solubility when used in coating.

[0052] In the compound represented by the general formula [1], R1 to R 21 At least one of R1 to R6 is preferably an alkyl group having 1 to 4 carbon atoms. More preferably, at least one of R7 to R8 is preferably an alkyl group having 1 to 4 carbon atoms. 10 At least one of R 11 ~R 18 At least one of the following, or R 19 ~R 21 At least one of R7 to R8 is an alkyl group having 1 to 4 carbon atoms. 10 At least one of these, preferably R8, is preferably an aryl group, more preferably a phenyl group.

[0053] Specific examples of the compound represented by the general formula [1] as a dopant material are shown below, but of course, the present invention is not limited to these. (A1,A5,A7-A9,A13,A16,A20,A22-A24,A28,A42,A44,B1,B5,B7-B9,B13,B15,B19,B22,B26,B28,B32,B34-B36,B40,B42,B43,C2,C8 are reference examples) .

[0054] [ka]

[0055] [ka]

[0056] [ka]

[0057] [ka]

[0058] [ka]

[0059] The exemplary compounds belonging to Group A are iridium complexes in which m = 2 in the general formula [1], and are iridium complexes in which two ligands having a dibenzofuran ring or a dibenzothiophene ring are coordinated. The emission wavelength of these compounds is in the green region. By using these compounds (iridium complexes), it is possible to provide a light-emitting element in the green region, with the maximum emission wavelength of the emission spectrum being 500 nm to 565 nm.

[0060] The exemplary compounds belonging to Group B are iridium complexes in which m = 1 in the general formula [1], and which are iridium complexes coordinated with one ligand having a dibenzofuran ring or a dibenzothiophene ring. The emission wavelengths of these compounds are in the green region. The presence of one ligand having a dibenzofuran ring or a dibenzothiophene ring results in a structure with a reduced molecular weight, which is advantageous for vapor deposition. The use of these compounds makes it possible to provide light-emitting devices in the green region, with a maximum emission wavelength of 500 nm to 565 nm in the emission spectrum.

[0061] The exemplary compounds belonging to group C are compounds in which an aryl group is bonded to the pyridine ring bonded to the dibenzofuran ring or dibenzothiophene ring in the general formula [1] (R7 to R 10 or (wherein either of the groups is an aryl group) is an iridium complex. The emission wavelength of these compounds is in the yellow-green to yellow region. By using these compounds, it is possible to provide a light-emitting device with an emission spectrum having a maximum emission wavelength of 565 nm to 590 nm in the yellow-green to yellow region.

[0062] Among these, the following compounds are preferred. [ka]

[0063] (3) Host material (hydrocarbon compound) Light-emitting materials with extended conjugated planes generally tend to overlap with the host, resulting in stronger intermolecular interactions. This can lead to the formation of exciplexes, potentially resulting in poor luminous efficiency and durability. Furthermore, the carbon-carbon bonds in host compounds tend to be stronger than carbon-nitrogen bonds. For example, when calculating 4,4'-di(9H-carbazol-9-yl)-1,1'-biphenyl (CBP) using b3-lyp / def2-SV(P), the calculated carbon-nitrogen bond energy is 3.86 eV, as shown below. In contrast, the calculated carbon-carbon bond energy is 5.04 eV. Therefore, it is preferable for the host to consist solely of hydrocarbon compounds, which are believed to be effective in improving luminous efficiency and durability.

[0064] [ka]

[0065] The hydrocarbon compound used as the host is preferably used under the following conditions. (3-1) The skeleton has at least one of a triphenylene ring, a phenanthrene ring, a chrysene ring, and a fluoranthene ring. (3-2)sp 3 It has no carbon.

[0066] (3-1) The host material has at least one of a triphenylene ring, a phenanthrene ring, a chrysene ring, and a fluoranthene ring in its skeleton.

[0067] It is known that triplet energy used in phosphorescent light-emitting devices undergoes energy transfer via the Dexter mechanism. The Dexter mechanism involves energy transfer through molecular contact. That is, by shortening the intermolecular distance between the host material and the guest material, energy transfer from the host material to the guest material is efficient.

[0068] In the present invention, by using a highly planar material as the host material, the intermolecular distance between the compound represented by general formula [1] and the host material is shortened, and energy transfer from the host to the compound represented by general formula [1] is facilitated with higher efficiency. As a result, a highly efficient organic light-emitting device can be provided. Here, examples of the highly planar structure include a triphenylene ring, a phenanthrene ring, a chrysene ring, and a fluoranthene ring. By using a compound having at least one of these structures as the host material, the compound represented by general formula [1] can provide a more efficient light-emitting device.

[0069] (3-2)sp 3 It has no carbon.

[0070] As described in the above explanation (3-1), the compound represented by the general formula [1] is a compound characterized in that the light-emitting properties are improved by improving the distance from the host material. 3 By forming a material that does not contain carbon, the distance to the compound represented by general formula [1] can be shortened.

[0071] In addition, all carbon atoms forming the basic skeleton are sp 2 Being composed of carbon atoms, it is thought that there is little structural change from the ground state to the charge accumulation state and excited state. Therefore, it is thought that even if the polycyclic aromatic hydrocarbon compound becomes an unstable cationic state due to the charge injected from the electrode, it tends to be resistant to degradation. Also, according to Stephan (reference: ACCOUNTS OF CHEMICAL RESERCH VOL.36, NO.4, p255, 2003), in carbon bonds, the bond energy of a single bond is 3.9 eV and that of a double bond is 7.5 eV, with the double bond being the larger bond energy. This also shows that sp 2 Compounds consisting only of carbon atoms are considered to be stable compounds from the standpoint of chemical bonding.

[0072] Specific examples of the host material are shown below, but the present invention is not limited to these.

[0073] [ka]

[0074] [ka]

[0075] The above-mentioned exemplary compounds have at least one of a triphenylene ring, a phenanthrene ring, a chrysene ring, and a fluoranthene ring in the skeleton, and are sp 3 These compounds do not contain carbon. Therefore, these compounds can be closer to the compound represented by general formula [1], and are therefore good host materials for transferring energy to the compound represented by general formula [1].

[0076] (4) Assist materials The LUMO (lowest unoccupied molecular orbital) level of the assist material is lower than that of the host material (farther from the vacuum level). The assist material is a material having the following characteristic (4-2), and preferably a material having the following characteristics (4-1) and (4-3). (4-1) A material having a HOMO (highest occupied molecular orbital) level larger (shallower) than the HOMO level of the host. (4-2) A material that has a LUMO level that is lower in energy (deeper) than the LUMO level of the host. (4-3) A material having a HOMO level with higher energy than the HOMO level of the host and a LUMO level with lower energy than the LUMO level of the host.

[0077] Materials with the characteristic (4-1) facilitate the injection and transport of holes into the light-emitting layer due to their shallow HOMO level, which results in lower device voltages and longer lifetimes due to the reduction in the incidence of excessive anionic states of the light-emitting material.

[0078] Materials with characteristic (4-2) contribute to a longer device life for the following reasons. Specifically, since the LUMO level of the host material is shallower (higher in energy) than that of the emitting material, adding an assist material with a LUMO level deeper than that of the host can prevent the emitting material from becoming excessively anionic. This is because the LUMO level of the iridium complex represented by general formula [1] acts as a strong trap level for electrons injected into the emitting layer, inevitably resulting in excessively anionic states. To resolve this situation, a material with characteristic (4-2), preferably an assist material with a LUMO level between the LUMO level of the host material and the LUMO level of the iridium complex represented by general formula [1], is added. This has been found to significantly improve the luminescence characteristics and device life.

[0079] Materials having the characteristic (4-3) can improve hole injection properties and alleviate electron trapping by the light-emitting material, resulting in a longer life.

[0080] The assist material is preferably a compound partially having any one of the following structures:

[0081] [ka] (In the above structure, X represents an oxygen atom, a sulfur atom, or a substituted or unsubstituted carbon atom.)

[0082] The above structure may be unsubstituted or substituted. The carbon atom represented by X may be unsubstituted or substituted. Examples of the substituent include a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, a heteroaryloxy group, an aryl group, a heterocyclic group, a silyl group, and an amino group.

[0083] Examples of halogen atoms include, but are not limited to, fluorine, chlorine, bromine, and iodine.

[0084] Examples of the alkyl group include, but are not limited to, a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a tertiary butyl group, a secondary butyl group, an octyl group, a cyclohexyl group, a 1-adamantyl group, and a 2-adamantyl group.

[0085] Examples of alkoxy groups include, but are not limited to, methoxy, ethoxy, propoxy, 2-ethyl-octyloxy, and benzyloxy groups.

[0086] Examples of the aryloxy group include, but are not limited to, a phenoxy group and a naphthoxy group.

[0087] Examples of heteroaryloxy groups include, but are not limited to, furanyloxy groups and thienyloxy groups.

[0088] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perylenyl, chrysenyl, and fluoranthenyl groups.

[0089] Examples of heterocyclic groups include, but are not limited to, pyridyl, pyrimidyl, pyrazyl, triazyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, and phenanthrolyl groups.

[0090] Examples of the silyl group include, but are not limited to, a trimethylsilyl group and a triphenylsilyl group.

[0091] Examples of the amino group include, but are not limited to, an N-methylamino group, an N-ethylamino group, an N,N-dimethylamino group, an N,N-diethylamino group, an N-methyl-N-ethylamino group, an N-benzylamino group, an N-methyl-N-benzylamino group, an N,N-dibenzylamino group, an anilino group, an N,N-diphenylamino group, an N,N-dinaphthylamino group, an N,N-difluorenylamino group, an N-phenyl-N-tolylamino group, an N,N-ditolylamino group, an N-methyl-N-phenylamino group, an N,N-dianisolylamino group, an N-mesityl-N-phenylamino group, an N,N-dimesitylamino group, an N-phenyl-N-(4-tert-butylphenyl)amino group, an N-phenyl-N-(4-trifluoromethylphenyl)amino group, an N-piperidyl group, a carbazolyl group, and an acridyl group.

[0092] The alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, and silyl group may further have a substituent. Examples of the substituent include deuterium, alkyl groups such as methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, and tertiary butyl group; aralkyl groups such as benzyl group; aryl groups such as phenyl group and biphenyl group; heterocyclic groups such as pyridyl group and pyrrolyl group; amino groups such as dimethylamino group, diethylamino group, dibenzylamino group, diphenylamino group, and ditolylamino group; alkoxy groups such as methoxy group, ethoxy group, and propoxy group; aryloxy groups such as phenoxy group; halogen atoms such as fluorine, chlorine, bromine, and iodine; and cyano group, but are not limited to these.

[0093] Specific examples of the assist material are shown below, but the material is not limited to these.

[0094] [ka]

[0095] (5) Other constituent materials As described above, the organic light-emitting device of the present invention contains at least an iridium complex represented by general formula [1], a host material, and an assist material in the light-emitting layer. However, in addition to these compounds, conventionally known low-molecular-weight and high-molecular-weight materials can also be used in the present invention as needed. More specifically, a hole-injecting and transporting material, a host, an assisting material, or an electron-injecting and transporting material can be used together with the iridium complex and the hydrocarbon compound.

[0096] The organic light-emitting element of this embodiment has at least a first electrode, a second electrode, and an organic compound layer disposed between these electrodes. One of the first electrode and the second electrode is an anode and the other is a cathode. In the organic light-emitting element of this embodiment, the organic compound layer may be a single layer or a laminate consisting of multiple layers, as long as it has an emitting layer. Here, when the organic compound layer is a laminate consisting of multiple layers, the organic compound layer may have, in addition to the emitting layer, a hole injection layer, a hole transport layer, an electron blocking layer, a hole / exciton blocking layer, an electron transport layer, an electron injection layer, etc. Furthermore, the emitting layer may be a single layer or a laminate consisting of multiple layers.

[0097] In the organic light-emitting device of this embodiment, at least one of the organic compound layers contains a compound represented by general formula [1]. Specifically, the compound represented by general formula [1] is contained in any of the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron blocking layer, hole / exciton blocking layer, electron transport layer, electron injection layer, etc. The compound represented by general formula [1] is preferably contained in the light-emitting layer.

[0098] In the organic light-emitting device of this embodiment, when the compound represented by general formula [1] is contained in the light-emitting layer, the light-emitting layer may be a layer consisting only of the compound represented by general formula [1], or may be a layer consisting of the compound represented by general formula [1] and other compounds. Here, when the light-emitting layer is a layer consisting of the compound represented by general formula [1] and other compounds, the compound represented by general formula [1] may be used as a host or a guest of the light-emitting layer. It may also be used as an assist material that can be contained in the light-emitting layer. Here, the host is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. The guest is a compound with a mass ratio smaller than that of the host among the compounds constituting the light-emitting layer, and is responsible for the main emission of light. The assist material is a compound with a mass ratio smaller than that of the host among the compounds constituting the light-emitting layer, and assists the emission of the guest. The assist material is also called a second host. The host material can also be called a first compound, and the assist material can also be called a second compound.

[0099] When the compound represented by the general formula [1] is used as a guest in the light-emitting layer, the concentration of the guest is preferably 0.1% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 30% by mass or less, and even more preferably 1% by mass or more and 15% by mass or less, based on the total mass of the light-emitting layer.

[0100] The present inventors conducted extensive research and found that using a compound represented by general formula [1] as a host or guest in an emitting layer, particularly as a guest in an emitting layer, results in an element that exhibits high efficiency, high luminance light output, and is extremely durable. This emitting layer may be a single layer or multiple layers, and by including a luminescent material having another emitting color, it is possible to mix the green to yellow emission of this embodiment with the emitting color. "Multiple layers" refers to a state in which an emitting layer and another emitting layer are stacked. In this case, the emitting color of the organic light-emitting element is not limited to green to yellow. More specifically, it may be white or a neutral color. In the case of white, the other emitting layer emits a color other than green to yellow, i.e., blue or red. Furthermore, the film is formed by vapor deposition or coating. Details of this will be explained in detail in the examples below.

[0101] The compound represented by general formula [1] can be used as a constituent material of an organic compound layer other than the light-emitting layer that constitutes the organic light-emitting device of this embodiment. Specifically, it may be used as a constituent material of an electron transport layer, an electron injection layer, a hole transport layer, a hole injection layer, a hole blocking layer, etc. In this case, the emission color of the organic light-emitting device is not limited to green to yellow. More specifically, it may emit white light or an intermediate color.

[0102] In addition to the compound represented by general formula [1], conventionally known low-molecular-weight and high-molecular-weight hole-injecting or hole-transporting compounds, host compounds, light-emitting compounds, electron-injecting or electron-transporting compounds, etc. may also be used together as needed. Examples of these compounds are listed below.

[0103] As the hole injection and transport material, a material with high hole mobility is preferred so that holes can be easily injected from the anode and the injected holes can be transported to the light-emitting layer. Furthermore, a material with a high glass transition temperature is preferred to reduce deterioration of film quality, such as crystallization, in organic light-emitting devices. Examples of low-molecular-weight and high-molecular-weight materials with hole injection and transport properties include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. Furthermore, the above-mentioned hole injection and transport materials are also suitable for use in electron blocking layers. Specific examples of compounds that can be used as hole injection and transport materials are listed below, but the present invention is not limited to these.

[0104] [ka]

[0105] Examples of light-emitting materials primarily involved in light-emitting function include, in addition to the compound represented by general formula [1], fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, anthracene derivatives, rubrene, etc.), quinacridone derivatives, coumarin derivatives, stilbene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, iridium complexes, platinum complexes, rhenium complexes, copper complexes, europium complexes, ruthenium complexes, and polymer derivatives such as poly(phenylenevinylene) derivatives, poly(fluorene) derivatives, and poly(phenylene) derivatives. Specific examples of compounds used as light-emitting materials are listed below, but of course, the present invention is not limited to these.

[0106] [ka]

[0107] [ka]

[0108] Examples of the light-emitting layer host or light-emitting assist material contained in the light-emitting layer include aromatic hydrocarbon compounds or derivatives thereof, as well as carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, and organic beryllium complexes. Specific examples of compounds used as the light-emitting layer host or light-emitting assist material contained in the light-emitting layer are shown below, but the present invention is not limited to these.

[0109] [ka]

[0110] The electron transport material can be arbitrarily selected from those capable of transporting electrons injected from the cathode to the light-emitting layer, and is selected taking into consideration the balance with the hole mobility of the hole transport material. Examples of materials having electron transport properties include oxadiazole derivatives, oxazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, organoaluminum complexes, and fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, chrysene derivatives, anthracene derivatives, etc.). Furthermore, the above electron transport materials are also suitable for use in hole-blocking layers. Specific examples of compounds used as electron transport materials are shown below, but of course, the present invention is not limited to these.

[0111] [ka]

[0112] <Configuration of organic light-emitting element> The organic light-emitting element is provided by forming an insulating layer, a first electrode, an organic compound layer, and a second electrode on a substrate. A protective layer, a color filter, a microlens, etc. may be provided on the second electrode. When a color filter is provided, a planarizing layer may be provided between the color filter and the protective layer. The planarizing layer may be made of an acrylic resin, etc. The same applies when a planarizing layer is provided between the color filter and the microlens.

[0113] [substrate] Examples of the substrate include quartz, glass, a silicon wafer, a resin, and a metal. Furthermore, the substrate may be provided with a switching element such as a transistor and wiring, and an insulating layer thereon. Any material can be used for the insulating layer, as long as it allows for the formation of a contact hole so that wiring can be formed between the first electrode and the insulating layer, and ensures insulation from wiring that is not connected. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0114] [electrode] A pair of electrodes can be used. The pair of electrodes may be an anode and a cathode. When an electric field is applied in the direction in which the organic light-emitting element emits light, the electrode with a higher potential is the anode, and the other is the cathode. It can also be said that the electrode that supplies holes to the light-emitting layer is the anode, and the electrode that supplies electrons is the cathode.

[0115] The anode material should have as high a work function as possible. Examples include simple metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten, mixtures containing these metals, alloys of these metals, and metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide. Conductive polymers such as polyaniline, polypyrrole, and polythiophene can also be used.

[0116] These electrode materials may be used alone or in combination of two or more. The anode may be composed of one layer or multiple layers.

[0117] When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates thereof can be used. The above materials can also function as a reflective film without functioning as an electrode. When used as a transparent electrode, transparent conductive oxide layers such as indium tin oxide (ITO) and indium zinc oxide can be used, but are not limited to these. Photolithography techniques can be used to form the electrode.

[0118] On the other hand, materials with a low work function are preferred for the cathode. Examples include alkali metals such as lithium, alkaline earth metals such as calcium, and metals such as aluminum, titanium, manganese, silver, lead, and chromium, as well as mixtures containing these metals. Alternatively, alloys combining these metals can be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver can be used. Metal oxides such as indium tin oxide (ITO) can also be used. These electrode materials can be used alone or in combination. The cathode can have either a single-layer or multi-layer structure. Among these, silver is preferred, and a silver alloy is even more preferred to reduce silver aggregation. The alloy ratio is not critical as long as silver aggregation can be reduced. For example, the silver:other metal ratio can be 1:1, 3:1, or the like.

[0119] The cathode may be a top-emission element using an oxide conductive layer such as ITO, or a bottom-emission element using a reflective electrode such as aluminum (Al), and is not particularly limited. The method for forming the cathode is not particularly limited, but DC and AC sputtering methods are more preferred because they provide good film coverage and make it easier to reduce resistance.

[0120] [Organic compound layer] The organic compound layer may be formed as a single layer or as multiple layers. When multiple layers are included, they may be called hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, or electron injection layer depending on their functions. The organic compound layer is mainly composed of organic compounds but may also contain inorganic atoms or inorganic compounds. For example, the organic compound layer may contain copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, or the like. The organic compound layer may be disposed between the first electrode and the second electrode, or may be disposed in contact with the first electrode and the second electrode.

[0121] The organic compound layers (hole injection layer, hole transport layer, electron blocking layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) constituting the organic light emitting device according to one embodiment of the present invention are formed by the method shown below.

[0122] The organic compound layer constituting the organic light-emitting device according to one embodiment of the present invention can be formed by dry processes such as vacuum deposition, ionization deposition, sputtering, plasma, etc. Alternatively to the dry process, a wet process can be used in which the compound is dissolved in an appropriate solvent and a layer is formed by a known coating method (for example, spin coating, dipping, casting, LB method, inkjet method, etc.).

[0123] Here, when a layer is formed by a vacuum deposition method or a solution coating method, crystallization is unlikely to occur and the layer has excellent stability over time. When a film is formed by a coating method, the film can be formed by combining with an appropriate binder resin.

[0124] Examples of the binder resin include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0125] These binder resins may be used singly or in combination as homopolymers or copolymers, and may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, if necessary.

[0126] [Protective layer] A protective layer may be provided on the second electrode. For example, by adhering glass with a moisture absorbent on the second electrode, the infiltration of water and other contaminants into the organic compound layer can be reduced, thereby reducing the occurrence of display defects. In another embodiment, a passivation film such as silicon nitride may be provided on the second electrode to reduce the infiltration of water and other contaminants into the organic compound layer. For example, after forming the second electrode, the second electrode may be transferred to another chamber without breaking the vacuum, and a 2 μm-thick silicon nitride film may be formed by CVD to serve as a protective layer. A protective layer may be provided using atomic layer deposition (ALD) after the CVD film formation. The material of the film formed by ALD is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, or the like. Silicon nitride may be further formed on the film formed by ALD by CVD. The film formed by ALD may have a thickness smaller than that of the film formed by CVD. Specifically, the thickness may be 50% or less, or even 10% or less.

[0127] [Color Filter] A color filter may be provided on the protective layer. For example, a color filter taking into consideration the size of the organic light-emitting element may be provided on a separate substrate and then bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer described above using photolithography technology. The color filter may be made of a polymer.

[0128] [Planarization layer] A planarization layer may be provided between the color filter and the protective layer. The planarization layer is provided for the purpose of reducing the unevenness of the underlying layer. It may also be called a material resin layer without limiting its purpose. The planarization layer may be composed of an organic compound, and may be either a low molecular weight or a high molecular weight, but a high molecular weight is preferred.

[0129] The planarizing layer may be provided above or below the color filter, and may be made of the same or different materials, such as polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0130] [Microlens] The organic light-emitting element or organic light-emitting device may have an optical component such as a microlens on its light-emitting side. The microlens may be made of acrylic resin, epoxy resin, or the like. The microlens may be intended to increase the amount of light extracted from the organic light-emitting element or organic light-emitting device or to control the direction of the extracted light. The microlens may have a hemispherical shape. When the microlens has a hemispherical shape, among the tangents to the hemisphere, there is a tangent that is parallel to the insulating layer, and the vertex of the microlens is the point of contact between this tangent and the hemisphere. The vertex of the microlens can be determined in the same way in any cross-sectional view. In other words, among the tangents to the semicircle of the microlens in the cross-sectional view, there is a tangent that is parallel to the insulating layer, and the vertex of the microlens is the point of contact between this tangent and the semicircle.

[0131] It is also possible to define the midpoint of a microlens. In the cross section of the microlens, a line segment is imagined from the point where an arc shape ends to the point where another arc shape ends, and the midpoint of this line segment can be called the midpoint of the microlens. The cross section for determining the vertex and midpoint may be a cross section perpendicular to the insulating layer.

[0132] [Counter substrate] An opposing substrate may be provided on the planarization layer. The opposing substrate is called an opposing substrate because it is provided at a position corresponding to the aforementioned substrate. The constituent material of the opposing substrate may be the same as that of the aforementioned substrate. When the aforementioned substrate is defined as a first substrate, the opposing substrate may be a second substrate.

[0133] [Pixel circuit] An organic light-emitting device having an organic light-emitting element may have a pixel circuit connected to the organic light-emitting element. The pixel circuit may be an active matrix type that controls the emission of the first light-emitting element and the second light-emitting element independently. The active matrix type circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light-emitting element, a transistor that controls the emission brightness of the light-emitting element, a transistor that controls the emission timing, a capacitor that holds the gate voltage of the transistor that controls the emission brightness, and a transistor for connecting to GND without going through the light-emitting element.

[0134] The light-emitting device has a display area and a peripheral area arranged around the display area. The display area has a pixel circuit, and the peripheral area has a display control circuit. The mobility of a transistor constituting the pixel circuit may be smaller than the mobility of a transistor constituting the display control circuit. The slope of the current-voltage characteristics of the transistor constituting the pixel circuit may be smaller than the slope of the current-voltage characteristics of the transistor constituting the display control circuit. The slope of the current-voltage characteristics can be measured by the so-called Vg-Ig characteristics. The transistor constituting the pixel circuit is a transistor connected to a light-emitting element, such as a first light-emitting element.

[0135] [Pixels] An organic light emitting device having an organic light emitting element may have a plurality of pixels, each of which has sub-pixels that emit different colors, for example, RGB colors.

[0136] A pixel emits light from an area called a pixel aperture. This area is the same as the first area. The pixel aperture may be 15 μm or less, or 5 μm or more. More specifically, it may be 11 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc. The distance between subpixels may be 10 μm or less, more specifically, it may be 8 μm, 7.4 μm, or 6.4 μm.

[0137] The pixels may be arranged in a known manner in a plan view. For example, they may be in a stripe arrangement, a delta arrangement, a pentile arrangement, or a Bayer arrangement. The shape of the subpixels in a plan view may be any known shape. For example, they may be rectangular, quadrilaterals such as diamonds, or hexagons. Of course, a shape that is close to a rectangle, rather than an exact shape, is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[0138] <Uses of the organic light-emitting device according to this embodiment> The organic light-emitting device according to this embodiment can be used as a component of a display device or a lighting device, and can also be used as an exposure light source for an electrophotographic image forming device, a backlight for a liquid crystal display device, or a light-emitting device having a white light source and a color filter.

[0139] The display device may be an image information processing device that has an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., has an information processing unit that processes the input information, and displays the input image on a display unit. The display device may have a plurality of pixels, at least one of which may have the organic light-emitting element of this embodiment and a transistor connected to the organic light-emitting element.

[0140] The display unit of the imaging device or inkjet printer may have a touch panel function. The driving method of this touch panel function may be an infrared method, a capacitance method, a resistive film method, or an electromagnetic induction method, and is not particularly limited. The display device may also be used in the display unit of a multifunction printer.

[0141] Next, a display device according to this embodiment will be described with reference to the drawings. Fig. 2 is a cross-sectional view showing an example of a display device having an organic light-emitting element and a transistor connected to the organic light-emitting element. The transistor is an example of an active element. The transistor may be a thin-film transistor (TFT).

[0142] FIG. 2(a) shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel includes sub-pixels 10. The sub-pixels are divided into 10R, 10G, and 10B based on their light emission. The emitted colors may be distinguished by the wavelength of light emitted from the light-emitting layer, or the light emitted from the sub-pixels may be selectively transmitted or color-converted using a color filter or the like. Each sub-pixel 10 includes a reflective electrode serving as a first electrode 2 on an interlayer insulating layer 1, an insulating layer 3 covering the edge of the first electrode 2, an organic compound layer 4 covering the first electrode 2 and the insulating layer 3, a transparent electrode serving as a second electrode 5, a protective layer 6, and a color filter 7.

[0143] A transistor and a capacitor element may be disposed below or inside the interlayer insulating layer 1. The transistor and the first electrode 2 may be electrically connected via a contact hole or the like (not shown).

[0144] The insulating layer 3 is also called a bank or a pixel separation film. It covers the edges of the first electrode 2 and is disposed to surround the first electrode 2. The portion where the insulating layer 3 is not disposed is in contact with the organic compound layer 4 and becomes a light-emitting region.

[0145] The organic compound layer 4 includes a hole injection layer 41 , a hole transport layer 42 , a first light-emitting layer 43 , a second light-emitting layer 44 , and an electron transport layer 45 .

[0146] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0147] The protective layer 6 reduces the penetration of moisture into the organic compound layer 4. Although the protective layer 6 is illustrated as being one layer, it may be multiple layers, and each layer may be an inorganic compound layer and an organic compound layer.

[0148] The color filters 7 are divided into 7R, 7G, and 7B depending on their colors. The color filters 7 may be formed on a planarization film (not shown). A resin protective layer (not shown) may be provided on the color filters 7. The color filters 7 may be formed on a protective layer 6. Alternatively, the color filters 7 may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0149] The display device 100 in FIG. 2(b) has an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 made of glass, silicon, or the like is provided with an insulating layer 12 on top of it. An active element such as the TFT 18 is disposed on the insulating layer 12, and a gate electrode 13, a gate insulating film 14, and a semiconductor layer 15 of the active element are disposed on top of it. The TFT 18 also includes a drain electrode 16 and a source electrode 17. An insulating film 19 is provided on top of the TFT 18. An anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20 provided in the insulating film 19.

[0150] The electrical connection method between the electrodes (anode 21, cathode 23) included in the organic light-emitting element 26 and the electrodes (source electrode 17, drain electrode 16) included in the TFT 18 is not limited to the embodiment shown in Fig. 2(b). In other words, it is sufficient that either the anode 21 or the cathode 23 is electrically connected to either the source electrode 17 or the drain electrode 16 of the TFT 18. TFT stands for thin film transistor.

[0151] 2(b), the organic compound layer 22 is illustrated as a single layer, but may be a multi-layer organic compound layer 22. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce deterioration of the organic light-emitting element 26.

[0152] In the display device 100 of FIG. 2(b), transistors are used as switching elements, but other switching elements may be used instead.

[0153] The transistors used in the display device 100 of Fig. 2(b) are not limited to transistors using single-crystal silicon wafers, but may also be thin-film transistors having an active layer on an insulating surface of a substrate. Examples of active layers include single-crystal silicon, amorphous silicon, microcrystalline silicon, and other non-single-crystal silicon, as well as non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Thin-film transistors are also called TFT elements.

[0154] The transistors included in the display device 100 of Fig. 2(b) may be formed within a substrate such as a Si substrate. Here, "formed within a substrate" means that the substrate itself, such as a Si substrate, is processed to form the transistors. In other words, having a transistor within a substrate can be seen as the substrate and the transistor being formed integrally.

[0155] The organic light-emitting element according to this embodiment has its emission brightness controlled by a TFT, which is an example of a switching element. By providing multiple organic light-emitting elements on a surface, an image can be displayed based on the emission brightness of each element. Note that the switching element according to this embodiment is not limited to a TFT, and may be a transistor formed from low-temperature polysilicon or an active matrix driver formed on a substrate such as a Si substrate. "On the substrate" can also be referred to as "inside the substrate." Whether to provide a transistor in the substrate or to use a TFT is determined by the size of the display unit. For example, for a display size of about 0.5 inches, it is preferable to provide the organic light-emitting element on a Si substrate.

[0156] 3 is a schematic diagram illustrating an example of a display device according to this embodiment. The display device 1000 may include a touch panel 1003, a display panel 1005, a frame 1006, a circuit board 1007, and a battery 1008 between an upper cover 1001 and a lower cover 1009. The touch panel 1003 and the display panel 1005 are connected by flexible printed circuits FPCs 1002 and 1004. Transistors are printed on the circuit board 1007. The battery 1008 may not be provided if the display device is not a portable device, and may be provided in a different position even if the display device is a portable device.

[0157] The display device according to this embodiment may have color filters having red, green, and blue colors, which may be arranged in a delta arrangement.

[0158] The display device according to the present embodiment may be used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display.

[0159] The display device according to this embodiment may be used as a display unit of an imaging device having an optical unit with a plurality of lenses and an imaging element that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the imaging element. The display unit may be a display unit exposed to the outside of the imaging device or a display unit disposed within a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0160] 4A is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1100 may include a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 may include a display device according to this embodiment. In this case, the display device may display not only an image to be captured, but also environmental information, imaging instructions, and the like. The environmental information may include the intensity of external light, the direction of external light, the speed at which the subject is moving, the possibility that the subject will be blocked by an obstruction, and the like.

[0161] Since the optimum timing for capturing an image is very short, it is better to display information as soon as possible. Therefore, it is preferable to use a display device using the organic light-emitting element of this embodiment. This is because the organic light-emitting element has a fast response speed. A display device using the organic light-emitting element can be used more preferably than a liquid crystal display device, which requires a high display speed.

[0162] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0163] FIG. 4(b) is a schematic diagram illustrating an example of an electronic device according to this embodiment. The electronic device 1200 has a display unit 1201, an operation unit 1202, and a housing 1203. The housing 1203 may have a circuit, a printed circuit board having the circuit, a battery, and a communication unit. The operation unit 1202 may be a button or a touch panel type reaction unit. The operation unit 1202 may be a biometric recognition unit that recognizes a fingerprint to perform unlocking or the like. An electronic device having a communication unit can also be called a communication device. The electronic device 1200 may further have a camera function by including a lens and an image sensor. An image captured by the camera function is displayed on the display unit 1201. Examples of the electronic device 1200 include a smartphone and a laptop computer.

[0164] FIG. 5 is a schematic diagram illustrating an example of a display device according to this embodiment. FIG. 5(a) illustrates a display device such as a television monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302. The display unit 1302 may use a light-emitting element according to this embodiment. The display device 1300 has the frame 1301 and a base 1303 that supports the display unit 1302. The base 1303 is not limited to the form shown in FIG. 5(a). The lower side of the frame 1301 may also serve as the base. The frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0165] FIG. 5(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in FIG. 5(b) is configured to be bendable, and is a so-called foldable display device. The display device 1310 has a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The first display unit 1311 and the second display unit 1312 may include light-emitting elements according to this embodiment. The first display unit 1311 and the second display unit 1312 may be a single, seamless display unit. The first display unit 1311 and the second display unit 1312 can be separated by the bending point. The first display unit 1311 and the second display unit 1312 may each display different images, or the first and second display units may display a single image.

[0166] FIG. 6(a) is a schematic diagram illustrating an example of a lighting device according to this embodiment. The lighting device 1400 may include a housing 1401, a light source 1402, a circuit board 1403, an optical filter 1404 that transmits light emitted by the light source 1402, and a light diffusion unit 1405. The light source 1402 may include an organic light-emitting element according to this embodiment. The optical filter 1404 may be a filter that improves the color rendering of the light source. The light diffusion unit 1405 can effectively diffuse light from the light source, such as for illumination, and deliver the light over a wide area. The optical filter 1404 and the light diffusion unit 1405 may be provided on the light emission side of the lighting. If necessary, a cover may be provided on the outermost surface.

[0167] The lighting device is, for example, a device that illuminates a room. The lighting device may emit white, daylight white, or any other color from blue to red. It may have a dimming circuit that dims these colors. The lighting device may have the organic light-emitting element of this embodiment and a power supply circuit connected thereto. The power supply circuit is a circuit that converts AC voltage to DC voltage. Furthermore, white has a color temperature of 4200K, and daylight white has a color temperature of 5000K. The lighting device may have a color filter.

[0168] The lighting device according to this embodiment may also include a heat dissipation unit, which dissipates heat from within the device to the outside, and may be made of a material such as a metal with a high specific heat capacity or liquid silicon.

[0169] 6(b) is a schematic diagram of an automobile, which is an example of a moving body according to this embodiment. The automobile has tail lamps, which are an example of lighting fixtures. The automobile 1500 has tail lamps 1501, and may be configured to turn on the tail lamps when braking or the like is performed.

[0170] The tail lamp 1501 may include an organic light-emitting element according to this embodiment. The tail lamp 1501 may include a protective member for protecting the organic light-emitting element. The protective member may be made of any material as long as it has a certain degree of strength and is transparent, but is preferably made of polycarbonate or the like. Polycarbonate may be mixed with a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like.

[0171] The automobile 1500 may have a body 1503 and a window 1502 attached thereto. The window 1502 may be a transparent display as long as it is not a window for checking the front and rear of the automobile. The transparent display may have an organic light-emitting element according to this embodiment. In this case, the constituent materials of the electrodes and the like of the organic light-emitting element are made of transparent materials.

[0172] The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body may have a body and a lighting device provided on the body. The lighting device may emit light to indicate the position of the body. The lighting device has the organic light-emitting element according to this embodiment.

[0173] An application example of the display device of each of the above-described embodiments will be described with reference to Fig. 7. The display device can be applied to a system that can be attached as a wearable device, such as smart glasses, an HMD, or a smart contact lens. The image capturing and display device used in such an application example includes an image capturing device capable of photoelectrically converting visible light and a display device capable of emitting visible light.

[0174] Fig. 7(a) is a schematic diagram showing an example of a wearable device according to an embodiment of the present invention. Using Fig. 7(a), glasses 1600 (smart glasses) according to one application example will be described. An imaging device 1602 such as a CMOS sensor or SPAD is provided on the front side of a lens 1601 of the glasses 1600. In addition, a display device according to each of the above-mentioned embodiments is provided on the back side of the lens 1601.

[0175] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the image capture device 1602 and the display device. The control device 1603 also controls the operations of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light onto the image capture device 1602.

[0176] FIG. 7(b) is a schematic diagram showing another example of a wearable device according to an embodiment of the present invention. Using FIG. 7(b), glasses 1610 (smart glasses) according to one application example will be described. The glasses 1610 have a control device 1612, which is equipped with an imaging device corresponding to the imaging device 1602 in FIG. 7(a) and a display device. A lens 1611 is formed with an optical system for projecting light emitted from the imaging device in the control device 1612 and the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power source that supplies power to the imaging device and the display device, and also controls the operation of the imaging device and the display device.

[0177] The control device 1612 may include a gaze detection unit that detects the wearer's gaze. The gaze detection may use infrared light. The infrared light emitter emits infrared light toward the eyeball of the user gazing at the display image. An imaging unit with a light-receiving element detects the reflected infrared light from the eyeball, thereby obtaining a captured image of the eyeball. A reduction unit that reduces light from the infrared light emitter to the display unit in a planar view reduces degradation of image quality. The user's gaze toward the displayed image is detected from the captured image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the captured image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used. More specifically, gaze detection processing based on the pupil-corneal reflex method is performed. Using the pupil-corneal reflex method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the image of the pupil and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0178] A display device according to one embodiment of the present invention may include an imaging device having a light receiving element, and may control the display image of the display device based on user line-of-sight information from the imaging device. Specifically, the display device determines a first field of view area where the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0179] The display area includes a first display area and a second display area different from the first display area, and a high-priority area is determined from the first display area and the second display area based on line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of areas other than the high-priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0180] Note that AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to an object in the line of sight from an image of the eyeball, using as training data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in an external device, it is transmitted to the display device via communication.

[0181] When display control is performed based on visual recognition detection, the smart glasses can be preferably applied to smart glasses that further include an imaging device for capturing images of the outside world. The smart glasses can display captured external information in real time.

[0182] 8(a) is a schematic diagram showing an example of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 40 is an electrophotographic image forming apparatus and includes a photoconductor 27, an exposure light source 28, a charging unit 30, a developing unit 31, a transfer unit 32, a transport roller 33, and a fixing unit 35. Light 29 is irradiated from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoconductor 27. The exposure light source 28 includes the organic light-emitting element according to this embodiment. The developing unit 31 includes toner and the like. The charging unit 30 charges the photoconductor 27. The transfer unit 32 transfers the developed image to a recording medium 34. The transport roller 33 transports the recording medium 34. The recording medium 34 is, for example, paper. The fixing unit 35 fixes the image formed on the recording medium 34.

[0183] 8(b) and 8(c) are diagrams showing an exposure light source 28 and are schematic diagrams illustrating a state in which multiple light-emitting units 36 are arranged on a long substrate. Arrow 37 indicates the direction parallel to the axis of the photoconductor, which represents the column direction in which the organic light-emitting elements are arranged. This column direction is the same as the axis direction about which the photoconductor 27 rotates. This direction can also be referred to as the long axis direction of the photoconductor 27. FIG. 8(b) shows a configuration in which the light-emitting units 36 are arranged along the long axis direction of the photoconductor 27. FIG. 8(c) shows a configuration different from FIG. 8(b), in which the light-emitting units 36 are arranged alternately in the column direction in the first and second columns. The first and second columns are arranged at different positions in the row direction. In the first column, multiple light-emitting units 36 are arranged at intervals. In the second column, light-emitting units 36 are located at positions corresponding to the intervals between the light-emitting units 36 in the first column. In other words, multiple light-emitting units 36 are also arranged at intervals in the row direction. The arrangement in FIG. 8(c) can also be described as a grid arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0184] As described above, by using a device using the organic light-emitting element according to this embodiment, it is possible to provide a stable display with good image quality even over a long period of time. [Example]

[0185] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0186] Example 1 (Synthesis of Exemplary Compound A3) [ka]

[0187] A 500 ml recovery flask was charged with 6.0 g (28.3 mmol) of D1, 4.8 g (28.3 mmol) of D2, 180 ml of water containing 4.5 g (42.4 mmol) of sodium carbonate, 90 ml of toluene, and 90 ml of ethanol, followed by degassing and nitrogen substitution. Then, 980 mg of Pd(PPh3)4 was added, and the reaction solution was heated and stirred at 90°C under a nitrogen stream for 3 hours. After completion of the reaction, the mixture was extracted with toluene, and the organic layer was concentrated to dryness. The resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 6.8 g of a white solid, D3 (yield: 80%).

[0188] After degassing the 2-ethoxyethanol (10 ml) solvent, 0.31 g (0.88 mmol) of iridium(III) chloride hydrate was added and stirred at room temperature for 30 minutes. 1.06 g (3.52 mmol) of D3 was then added, heated to 120°C, and stirred for 6 hours. After cooling, water was added, filtered, and washed with water. This was dried to obtain 0.70 g (48% yield) of a yellowish-brown solid, D4.

[0189] After degassing the dichloromethane (35 ml) solvent, 0.70 g (0.42 mmol) of D4 and 0.2 g (0.83 mmol) of AgOTf were added and stirred, followed by addition of methanol (9 ml) and stirring at room temperature for 3 hours. The solvent was distilled off to obtain 1.00 g of D5.

[0190] In a separate container, ethanol (18 ml) was degassed, and then 0.60 g (0.60 mmol) of D5 and 0.15 g (0.99 mmol) of D6 were added and refluxed for 3 hours. After cooling, the mixture was filtered and purified by column chromatography using a chloroform / heptane mixed solvent. After distilling off the solvent, methanol was added, filtered, and washed with methanol. This was dried to obtain 0.40 g (70% yield) of a dark yellow solid, A3.

[0191] 1 x 10 of example compound A3 -5 The emission spectrum of the toluene solution at 100 mol / L was measured by photoluminescence at an excitation wavelength of 350 nm using a Hitachi F-4500, and a spectrum with a maximum intensity at 530 nm was obtained.

[0192] The exemplary compound A3 was subjected to mass spectrometry using MALDI-TOF-MS (Autoflex LRF manufactured by Bruker). [MALDI-TOF-MS] Measured value: m / z=947 Calculated value: C 53 H 44 IrN3O2=947

[0193] [Examples 2 to 20 (Synthesis of Exemplary Compounds)] (Examples 3, 6, 8, 10, 12, and 16 are reference examples.) As shown in Tables 1 to 4, the exemplary compounds shown in Examples 2 to 20 were synthesized in the same manner as in Example 1, except that raw materials D1, D2, and D6 in Example 1 were replaced with raw materials 1, 2, and 3, respectively. The actual measured values ​​(m / z) of the mass spectrometry results measured in the same manner as in Example 1 are also shown.

[0194] [Table 1]

[0195] [Table 2]

[0196] [Table 3]

[0197] [Table 4]

[0198] [Example 21] An organic light-emitting device with a bottom emission structure was fabricated by sequentially forming an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode on a substrate.

[0199] First, an ITO film was formed on a glass substrate and then patterned as desired to form an ITO electrode (anode). At this time, the film thickness of the ITO electrode was set to 100 nm. The substrate on which the ITO electrode was formed was used as the ITO substrate in the following process. Next, a 1.33 × 10 -4 Vacuum deposition was performed by resistance heating in a vacuum chamber at 100 Pa to successively form an organic compound layer and an electrode layer shown in Table 5 on the ITO substrate. At this time, the electrode area of ​​the opposing electrode (metal electrode layer, cathode) was 3 mm 2 It was made to be like this.

[0200] [Table 5]

[0201] The characteristics of the obtained device were measured and evaluated. The maximum emission wavelength of the light-emitting device was 532 nm, and the efficiency (cd / A) was 58. Furthermore, at a current density of 100 mA / cm 2 A continuous driving test was carried out at 100°C, and the time when the luminance degradation rate reached 5% was measured. When the time when the luminance degradation rate of Comparative Example 1 reached 5% was set to 1.0, the luminance degradation rate ratio of this example was 1.9.

[0202] In this example, the measuring device was specifically a microcurrent meter 4140B manufactured by Hewlett-Packard Company to measure the current-voltage characteristics, and a BM7 manufactured by Topcon Corporation to measure the luminance.

[0203] [Examples 22 to 31, Comparative Examples 1 to 5] (Examples 22, 23, 28, and 29 are reference examples) In Examples 22 to 31 and Comparative Examples 1 to 5, organic light-emitting devices were produced in the same manner as in Example 21, except that the compounds were appropriately changed to those shown in Table 6. The characteristics of the obtained devices were measured and evaluated in the same manner as in Example 21. The measurement results are shown in Table 6.

[0204] [Table 6]

[0205] Table 7 shows the LUMO levels of the host materials and assist materials used in Examples 21 to 31 and Comparative Examples 1 to 5. The LUMO levels of the host materials and assist materials were calculated by determining the ionization potential (IP) using an air photoelectron spectrometer AC-3 manufactured by Riken Keiki Co., Ltd. and subtracting the optical band gap (BG) determined using an ultraviolet-visible spectrophotometer manufactured by JASCO Corporation.

[0206] [Table 7]

[0207] As can be seen from Table 6, the efficiency (cd / A) of Comparative Example 1 was 38, and the light-emitting devices of the Examples had higher luminous efficiency. This means that the device configuration according to the present invention has a higher efficiency. Furthermore, the luminance degradation rate ratios of Comparative Examples 2 to 5 were 0.7 to 0.9, and the light-emitting devices of the Examples had a longer life. The LUMO levels of the assist materials used in Comparative Examples 2 and 3 were both 2.7 eV, which is equivalent to the LUMO level of the host material. The LUMO levels of the assist materials used in Comparative Examples 4 and 5 were both 2.5 eV, which is shallower than the LUMO level of the host material. This shows that a green light-emitting device with excellent durability and a maximum emission wavelength of 500 nm to 565 nm can be provided because the LUMO level of the assist material is deeper (smaller) than the LUMO level of the host material.

[0208] [Examples 32 to 36, Comparative Examples 6 to 8] (Example 36 is a reference example) In Examples 32 to 36 and Comparative Examples 6 to 8, organic light-emitting devices were fabricated in the same manner as in Example 21, except that the compounds were appropriately changed to those shown in Table 8. The characteristics of the obtained devices were measured and evaluated in the same manner as in Example 21. The measurement results are shown in Table 8. The LUMO levels of the host materials used in Examples 32 to 36 and Comparative Examples 6 to 8 and the assist materials used in Examples 32 to 36 are as shown in Table 7.

[0209] [Table 8]

[0210] As can be seen from Table 8, the efficiency (cd / A) of Comparative Example 6 was 25, and the light-emitting device according to the Example had a higher luminous efficiency. This is due to the device configuration according to the present invention having a higher quantum yield. Furthermore, the luminance degradation rate ratios of Comparative Examples 7 and 8 were both 0.8, and the light-emitting device according to the Example had a longer life. The LUMO level of the assist material used in Comparative Example 7 was 2.7 eV, which is equivalent to the LUMO level of the host material. The LUMO level of the assist material used in Comparative Example 8 was 2.5 eV, which is shallower than the LUMO level of the host material. This shows that a yellow light-emitting device with excellent durability and a maximum emission wavelength of 565 nm to 590 nm can be provided because the LUMO level of the assist material is deeper (smaller) than the LUMO level of the host material. [Explanation of symbols]

[0211] 1: interlayer insulating layer, 2: first electrode, 3: insulating layer, 4: organic compound layer, 5: second electrode, 6: protective layer, 7: color filter, 10: subpixel, 11: substrate, 12: insulating layer, 13: gate electrode, 14: gate insulating film, 15: semiconductor layer, 16: drain electrode, 17: source electrode, 18: TFT, 19: insulating film, 20: contact hole, 21: anode, 22: organic compound layer, 23: cathode, 24: first protective layer, 25: second protective layer, 26: organic light-emitting element, 100: display device< / x>

Claims

1. an anode, a light-emitting layer, and a cathode in this order; the light-emitting layer includes a dopant material, a host material, and an assist material; The dopant material is a compound represented by the following general formula [1]: the host material is a hydrocarbon compound; The organic light-emitting element is characterized in that the LUMO level of the assist material is lower (farther from the vacuum level) than the LUMO level of the host material. 【Chemistry 1】 In formula [1], R 1 R to R, R to R are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group. R 8 is selected from a substituted or unsubstituted alkyl group having from 1 to 4 carbon atoms, and a substituted or unsubstituted phenyl group. X represents O or S. m represents an integer of 1 or more and 3 or less, and n represents an integer of 0 or more and 2 or less, provided that m+n is 3. Substructure IrL n is any of the structures represented by the following general formulas [2] and [3]. 【Chemistry 2】 In formulas [2] and [3], R 11 ~R 21 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

2. 2. The organic light-emitting device according to claim 1, wherein the assist material is a compound partially having any one of the following structures: 【Transformation 3】 (In the above structure, X represents an oxygen atom, a sulfur atom, or a substituted or unsubstituted carbon atom.)

3. 3. The organic light-emitting element according to claim 1, wherein the host material has at least one of a triphenylene ring, a phenanthrene ring, a chrysene ring, and a fluoranthene ring in its skeleton.

4. The R 1 ~R 21 4. The organic light-emitting element according to claim 1, wherein at least one of the groups is an alkyl group having 1 to 4 carbon atoms.

5. The R 8 5. The organic light-emitting device according to claim 1, wherein R is a tertiary butyl group or a phenyl group.

6. 6. The organic light-emitting device according to claim 1, wherein the dopant material is any one of the following compounds: 【Chemistry 4】

7. 7. The organic light-emitting device according to claim 1, which emits green light.

8. 7. The organic light-emitting device according to claim 1, which emits yellow light.

9. 9. The organic light-emitting element according to claim 1, further comprising another light-emitting layer disposed in a stacked state with the light-emitting layer, the another light-emitting layer emitting light of a color different from the color of light emitted by the light-emitting layer.

10. The organic light-emitting device according to claim 9, which emits white light.

11. A display device comprising a plurality of pixels, at least one of the plurality of pixels comprising the organic light-emitting element according to claim 1 and an active element connected to the organic light-emitting element.

12. 12. The display device according to claim 11, further comprising a color filter.

13. an optical unit having a plurality of lenses, an image pickup element that receives light that has passed through the optical unit, and a display unit that displays an image picked up by the image pickup element; The photoelectric conversion device, wherein the display section comprises the organic light-emitting element according to claim 1 .

14. 11. An electronic device comprising: a display unit having the organic light-emitting element according to claim 1; a housing in which the display unit is provided; and a communication unit provided in the housing and communicating with an external device.

15. 11. A lighting device comprising: a light source having the organic light-emitting element according to claim 1; and a light diffusion section or an optical filter that transmits light emitted by the light source.

16. A moving body comprising: a lamp having the organic light-emitting element according to claim 1; and a vehicle on which the lamp is provided.

17. An exposure light source for an electrophotographic image forming apparatus, comprising the organic light-emitting element according to claim 1 .

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