Organic light-emitting element, organic compound, display device, photoelectric conversion device, electric equipment, lighting device, mobile object, and exposure light source

Abstract

To provide an organic light emitting element excellent in drive durability performance.SOLUTION: An organic light emitting element comprises a positive electrode, a negative electrode and a light emitting layer that is arranged between the positive electrode and the negative electrode. The light emitting layer comprises a first compound represented by general formula [1] in the figure and a second compound represented by general formula [2] in the figure. In general formula [1], L represents a bidentate ligand which has naphtho[2,1-f]isoquinoline or phenanthro[2,1-f]isoquinoline as a main skeleton.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] An organic light-emitting device (hereinafter sometimes referred to as an "organic electroluminescence device" or "organic EL device") is an electronic device having a pair of electrodes and an organic compound layer disposed between the electrodes. By injecting electrons and holes from the pair of electrodes, excitons of a light-emitting organic compound in the organic compound layer are generated, and when the excitons return to the ground state, the organic light-emitting device emits light.

[0003] Recent progress in organic light-emitting devices has been remarkable, and their features include low driving voltage, a wide range of emission wavelengths, high-speed response, and the ability to make light-emitting devices thinner and lighter.

[0004] Among organic light-emitting devices, phosphorescent light-emitting devices have a phosphorescent material in an organic compound layer constituting the organic light-emitting device, and emit light derived from the triplet excitons. However, there is room for further improvement in the luminous efficiency and durability of phosphorescent light-emitting devices, and there is a need to improve the luminescence quantum yield of the phosphorescent material and to suppress deterioration of the molecular structure of the host material molecules in the luminescent layer.

[0005] Patent Documents 1 to 3 disclose the following compounds 1-a and 1-b as phosphorescent light-emitting materials, which are iridium complexes having aryl-naphtho[2,1-f]isoquinoline as a ligand. Patent Documents 1 to 3 also disclose organic light-emitting devices in which the following compound 1-a is contained as a guest in the light-emitting layer.

[0006] [ka] [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-141425 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-154615 [Patent Document 3] Japanese Patent Application Laid-Open No. 2014-154614 Summary of the Invention [Problem to be solved by the invention]

[0008] Patent Documents 1 to 3 disclose organic light-emitting devices containing the above-mentioned compound 1-a in the light-emitting layer, but these organic light-emitting devices still have problems in terms of driving durability.

[0009] 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 element having excellent driving durability. [Means for solving the problem]

[0010] An organic light-emitting device according to one aspect of the present invention includes an anode, a cathode, and a light-emitting layer disposed between the anode and the cathode, The light-emitting layer is characterized by comprising a first compound represented by the following general formula [1] and a second compound represented by the following general formula [2].

[0011] [ka]

[0012] [ka]

[0013] In the general formula [1], Ir is iridium. L and L' represent different bidentate ligands. m is any one of 1 to 3, n is any one of 0 to 2, and m+n=3. The partial structure Ir(L) m is a partial structure represented by the following general formula [1-1] or [1-2], and L' is a bidentate ligand represented by the following general formula [1-3] or [1-4].

[0014] [ka]

[0015] [ka]

[0016] [ka]

[0017] [ka]

[0018] In the general formula [1-1], R1 is any one of a fluorine atom, an alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, an aryl group, and a heterocyclic group. In the general formulas [1-1] and [1-2], R2 to R 14 and R 18 ~R 21 are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. Adjacent R1 to R4 may form a ring together. In general formula [1-3], R 15 ~R 17are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. 32 ~R 39 are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. 32 ~R 39 may form a ring together.

[0019] (In the general formula [2], p and q are each independently 0, 1, or 2, and satisfy the following relational expression: 0≦p+q≦4 In the general formula [2], Ar1 to Ar4 are each independently selected from benzene, naphthalene, phenanthrene, chrysene, triphenylene, picene, fluoranthene, and compounds represented by the following general formula [2-1], each of which does not have an alkyl group as a substituent, and at least one of Ar1 to Ar4 is phenanthrene, chrysene, triphenylene, picene, fluoranthene, or a compound represented by the general formula [2-1].

[0020] [ka]

[0021] (In general formula [2-1], Q represents an oxygen atom, a sulfur atom, or a nitrogen atom, and ring B1 and ring B2 are each independently selected from a hydrocarbon aromatic ring and a heterocyclic ring. Ring B1 and ring B2 may have a substituent, and when Q is a nitrogen atom, Q may have an aryl group or a heterocyclic group as a substituent. Adjacent Qs, ring B1, and ring B2 may form a ring directly or via a substituent.) [Effects of the Invention]

[0022] According to the present invention, it is possible to provide an organic light-emitting device having excellent driving durability. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a schematic diagram summarizing the structures of the guest and host in each of the organic light-emitting devices of Examples and Comparative Examples, and the state of interaction between the guest and the host. [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 a portable 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 automobile as an example of a moving body according to an embodiment of the present invention. [Figure 7] 1A and 1B are schematic diagrams illustrating an example of a wearable device according to an embodiment of the present invention, each of which has an imaging device; [Figure 8] 1 is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention. [Figure 9] FIG. 2 is a schematic diagram illustrating an example of an exposure light source of the image forming apparatus according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] <Organic light-emitting element> First, an organic light-emitting device according to this embodiment will be described. The organic light-emitting device according to this embodiment has an anode, a cathode, and an emitting layer disposed between the anode and the cathode. The emitting layer has a first compound represented by the following general formula [1] or [3]. The first compound represented by the following general formula [1] or [3] will be described later.

[0025] [ka]

[0026] In the general formula [1], Ir represents iridium. L and L' represent different bidentate ligands. m is any one of 1 to 3, n is any one of 0 to 2, and m + n = 3. That is, when m is 1, n is 2, when m is 2, n is 1, and when m is 3, n is 0.

[0027] [ka]

[0028] In the general formula [3], Ir is iridium. L, L', and L" each represent a different bidentate ligand.

[0029] Specific examples of the organic light-emitting device according to this embodiment include a multilayer device structure in which electrode layers and organic compound layers shown in the following (1) to (6) are sequentially stacked on a substrate. In any device structure, the organic compound layers always include a light-emitting layer containing a light-emitting material. (1) Anode / Emitting layer / Cathode (2) Anode / hole transport layer / light-emitting layer / electron transport layer / cathode (3) Anode / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (4) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / cathode (5) Anode / hole injection layer / hole transport layer / light-emitting layer / electron transport layer / electron injection layer / cathode (6) Anode / hole transport layer / electron blocking layer / light-emitting layer / hole blocking layer / electron transport layer / cathode

[0030] However, these device configuration examples are merely very basic device configurations, and the device configuration of the organic light-emitting device of the present invention is not limited to these. For example, an insulating layer, an adhesive layer, or an interference layer may be provided at the interface between the electrode and the organic compound layer. Furthermore, the electron transport layer or the hole transport layer may have a multilayer structure having two layers with different ionization potentials. The light-emitting layer may have a multilayer structure having two layers each containing a different light-emitting material. In addition to these, various layer configurations can be adopted.

[0031] In this embodiment, the extraction mode (device configuration) of light output from the light-emitting layer may be a so-called bottom emission type in which light is extracted from the electrode on the substrate side, or a so-called top emission type in which light is extracted from the opposite side of the substrate. Also, a double-sided emission type in which light is extracted from the substrate side and the opposite side of the substrate may be adopted.

[0032] Among the device configurations shown in (1) to (6), the configuration (6) is preferable because it has both an electron blocking layer and a hole blocking layer. That is, the configuration (6) having an electron blocking layer and a hole blocking layer can reliably confine both hole and electron carriers within the light-emitting layer, resulting in an organic light-emitting device with no carrier leakage and high luminous efficiency.

[0033] In the organic light-emitting device according to this embodiment, the first compound represented by general formula [1] or [3] is preferably contained in the light-emitting layer of the organic compound layer. The first compound represented by general formula [1] is an iridium complex, which is a type of organometallic complex.

[0034] The organic light-emitting device according to this embodiment preferably contains, in addition to the first compound, a second compound different from the compound represented by general formula [1] or [3] in the light-emitting layer. In this case, the compound contained in the light-emitting layer has different uses depending on its concentration in the light-emitting layer. Specifically, the compound is classified into a main component and a subcomponent depending on its concentration in the light-emitting layer.

[0035] The main component compound is the compound with the largest weight ratio (content concentration) among the compounds contained in the light-emitting layer, and is also called a host. The host is a compound 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 host may also be called a host material or host molecule.

[0036] The compound serving as the minor component is a compound other than the main component, and can be called a guest (dopant), a light-emitting assist material, or a charge injection material depending on the function of the compound. The guest, which is one type of minor component, is a compound (light-emitting material) that is primarily responsible for light emission in the light-emitting layer. The guest can also be called a guest material or a guest molecule. The light-emitting assist material, which is one type of minor component, is a compound that assists the guest in emitting light and has a smaller weight ratio (content concentration) in the light-emitting layer than the host. The light-emitting assist material is also called a second host based on its function. In this embodiment, the (light-emitting) assist material is preferably an iridium complex. However, the iridium complex used as the (light-emitting) assist material is an iridium complex other than the iridium complex of general formula [1]. In other words, the organic light-emitting device according to this embodiment may have a first compound represented by general formula [1] or [3], and a second compound and a third compound that are different from the compound represented by general formula [1] or [3], respectively. Furthermore, the third compound may be an iridium complex different from the compound represented by general formula [1] or [3].

[0037] The guest concentration is 0.01% by weight to 50% by weight, and preferably 0.1% by weight to 20% by weight, based on the total amount of the constituent materials of the light-emitting layer. From the viewpoint of preventing concentration quenching, the guest concentration is particularly preferably 10% by weight or less.

[0038] In this embodiment, the guest may be contained uniformly throughout the layer in which the host serves as a matrix, or may be contained with a concentration gradient. Alternatively, the guest may be contained partially in a specific region within the layer, so that the light-emitting layer has a region containing only the host and no guest.

[0039] In this embodiment, a preferred embodiment is one in which a first compound represented by general formula [1] or [3] serves as a guest and a second compound different from the compound represented by general formula [1] or [3] serves as a host, both of which are contained in the light-emitting layer. In this case, in order to assist the transport of excitons and carriers, the light-emitting layer may further contain another phosphorescent material in addition to the iridium complex represented by general formula [1]. In other words, the organic light-emitting device according to this embodiment may include a first compound represented by general formula [1] or [3], a second compound different from the compound represented by general formula [1] or [3], and a third compound different from the compound represented by general formula [1] or [3]. Furthermore, the third compound may be a phosphorescent material different from the compound represented by general formula [1] or [3].

[0040] Furthermore, for the purpose of assisting the transport of excitons and carriers, the light-emitting layer may further contain a compound (fourth compound) other than the compounds represented by the first to third compounds as a second host.

[0041] The second compound may be a compound represented by the following general formula [2]. The second compound represented by the following general formula [2] will be described later. In particular, when the first compound is a compound represented by the general formula [1], the second compound is preferably a compound represented by the following general formula [2].

[0042] [ka]

[0043] <First compound (iridium complex)> Next, the first compound, which is one of the constituent materials of the organic light-emitting device of this embodiment, will be described. The first compound, which is one of the constituent materials of the organic light-emitting device of this embodiment, is a compound represented by the following general formula [1] or the following general formula [3], and is an iridium complex. The first compound represented by the following general formula [1] or the following general formula [3] emits red light.

[0044] [ka]

[0045] [ka]

[0046] The compound represented by the general formula [1] and the compound represented by the general formula [3] will be described in detail below.

[0047] <Compound represented by general formula [1]>

[0048] [ka]

[0049] In the general formula [1], Ir is iridium. L and L' represent different bidentate ligands. m is any number from 1 to 3, n is any number from 0 to 2, and m+n=3. Partial structure Ir(L) m is a partial structure represented by the following general formula [1-1] or [1-2], and L' is a bidentate ligand represented by the following general formula [1-3] or [1-4].

[0050] [ka]

[0051] [ka]

[0052] [ka]

[0053] [ka]

[0054] In the general formulas [1-1] and [1-2], R1 is any one of a fluorine atom, an alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, an aryl group, and a heterocyclic group.

[0055] In the general formulas [1-1] and [1-2], R to R 14 and R 18 ~R 21 are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. Adjacent R1 to R4 may together form a ring.

[0056] In the general formula [1-3], R 15 ~R 17 are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group.

[0057] In the general formula [1-4], R 32 ~R 39 are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. 32 ~R 39 may be joined together to form a ring.

[0058] (ligand L) In the general formulas [1-1] and [1-2], the alkyl group represented by R1 is preferably an alkyl group having 1 to 4 carbon atoms, more preferably a methyl group. Specific examples of the alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, and a tert-butyl group.

[0059] In other words, the partial structure represented by the general formula [1-1] is preferably a partial structure represented by the following general formula [1-5]: In the following general formula [1-5], adjacent R2 to R4 may form a ring together.

[0060] [ka]

[0061] R2~R 14 and R 18 ~R 21 The alkyl group represented by the formula (I) is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms. Specific examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an i-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, and a cyclohexyl group. Of these, a methyl group or a tert-butyl group is more preferred.

[0062] R1~R 14 and R 18 ~R 21 Specific examples of the alkoxy group represented by the formula (I) include a methoxy group, an ethoxy group, an i-propoxy group, an n-butoxy group, and a tert-butoxy group, with a methoxy group being preferred.

[0063] R2~R 14 and R 18 ~R 21Specific examples of the substituted amino group represented by the formula (I) include 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, etc. Among these, an N,N-dimethylamino group or an N,N-diphenylamino group is preferred.

[0064] Specific examples of the aryl group represented by R1 include a phenyl group, a naphthyl group, a biphenyl group, a terphenyl group, etc. Among these, a phenyl group is more preferred.

[0065] R2~R 14 and R 18 ~R 21 Specific examples of the aryl group represented by the formula (I) include a phenyl group, a naphthyl group, a phenanthryl group, an anthryl group, a fluorenyl group, a biphenylenyl group, an acenaphthylenyl group, a chrysenyl group, a pyrenyl group, a triphenylenyl group, a picenyl group, a fluoranthenyl group, a perylenyl group, a naphthacenyl group, a biphenyl group, and a terphenyl group. Among these, a phenyl group, a naphthyl group, a fluorenyl group, or a biphenyl group is preferred, and a phenyl group is more preferred.

[0066] Specific examples of the heterocyclic group represented by R1 include a thienyl group, a pyrrolyl group, a pyrazinyl group, and a pyridyl group.

[0067] R2~R 14 and R 18 ~R 21Specific examples of the heterocyclic group represented by the formula (I) include a thienyl group, a pyrrolyl group, a pyrazinyl group, a pyridyl group, an indolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an acridinyl group, a phenanthrolinyl group, a carbazolyl group, a benzo[a]carbazolyl group, a benzo[b]carbazolyl group, a benzo[c]carbazolyl group, a phenazinyl group, a phenoxazinyl group, a phenothiazinyl group, a benzothiophenyl group, a dibenzothiophenyl group, a benzofuranyl group, a dibenzofuranyl group, an oxazolyl group, and an oxadiazolyl group.

[0068] The substituents that the alkyl group, aryl group, and heterocyclic group may further have are not particularly limited, and examples thereof include alkyl groups such as a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an i-pentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, and a cyclohexyl group; alkoxy groups such as a methoxy group, an ethoxy group, an i-propoxy group, an n-butoxy group, and a tert-butoxy group; and an N-methylamino group. , N-ethylamino group, N,N-dimethylamino group, N,N-diethylamino group, N-methyl-N-ethylamino group, N-benzylamino group, N-methyl-N-benzylamino group, N,N-dibenzylamino group, anilino group, N,N-diphenylamino group, N,N-dinaphthylamino group, N,N-difluorenylamino group, N-phenyl-N-tolylamino group, N,N-ditolylamino group, N-methyl-N-phenylamino group, N,N-dianisolylamino group, N-mesityl-N-phenylamino group, N,N -Substituted amino groups such as dimesitylamino, N-phenyl-N-(4-tert-butylphenyl)amino, and N-phenyl-N-(4-trifluoromethylphenyl)amino; aryl groups such as phenyl, naphthyl, phenanthryl, anthryl, fluorenyl, biphenylenyl, acenaphthylenyl, chrysenyl, pyrenyl, triphenylenyl, picenyl, fluoranthenyl, perylenyl, naphthacenyl, biphenyl, and terphenyl; thienyl, pyrrolyl, and pyrazinyl heterocyclic groups such as a pyridyl group, an indolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an acridinyl group, a phenanthrolinyl group, a carbazolyl group, a benzo[a]carbazolyl group, a benzo[b]carbazolyl group, a benzo[c]carbazolyl group, a phenazinyl group, a phenoxazinyl group, a phenothiazinyl group, a benzothiophenyl group, a dibenzothiophenyl group, a benzofuranyl group, a dibenzofuranyl group, an oxazolyl group, an oxadiazolyl group, a cyano group, a trifluoromethyl group, and the like.

[0069] The substituents which the alkyl group, aryl group and heterocyclic group may further have are preferably a methyl group, a tert-butyl group, a methoxy group, an N,N-dimethylamino group, an N,N-diphenylamino group, a phenyl group, a naphthyl group, a fluorenyl group or a biphenyl group, and particularly preferably a methyl group, a tert-butyl group or a phenyl group.

[0070] In this embodiment, R to R shown in any of general formulas [1-1] and [1-2] 14 and R 18 ~R 21 is preferably a substituent selected from a hydrogen atom, a fluorine atom, and an alkyl group having 1 to 10 carbon atoms, and more preferably a substituent selected from a hydrogen atom, a fluorine atom, a methyl group, and a tert-butyl group.

[0071] As described above, the iridium complex represented by general formula [1] is an iridium complex in which at least one of the ligands constituting the complex is a ligand having naphtho[2,1-f]isoquinoline or phenanthro[2,1-f]isoquinoline as the main skeleton. As a result of extensive research, the present inventors have found that an organic light-emitting device using a compound having a substituent other than a hydrogen atom in R1 in the light-emitting layer of general formulas [1-1] and [1-2] has particularly superior durability characteristics compared to a case in which R1 is a hydrogen atom. Furthermore, the present inventors have found that an organic light-emitting device having an emission layer containing this iridium complex as a guest and a second compound described below as a host has particularly excellent durability characteristics.

[0072] Furthermore, as described below, we have found that complexes containing phenanthro[2,1-f]isoquinoline as a ligand have higher oscillator strength and narrower emission spectra than complexes containing naphtho[2,1-f]isoquinoline as a ligand (Table 2). That is, complexes containing a ligand with a structure in which a fused ring extends from the nitrogen atom coordinately bonded to the Ir atom in the opposite direction to the Ir atom, as represented by general formula [2-2], exhibit higher oscillator strength and sharper emission spectra than those containing complexes with general formula [2-1]. The narrower emission spectrum improves color purity, expanding the color reproduction range when used, for example, in displays. Therefore, among the iridium complexes represented by general formula [1], iridium complexes containing phenanthro[2,1-f]isoquinoline as a ligand, as represented by formula [2-2], are particularly preferred from the viewpoint of color purity of emission.

[0073] (ligand L') Next, the ligand L' will be described. As described above, the ligand L' is a monovalent bidentate ligand represented by the above general formula [1-3] or [1-4]. Examples of L' include acetylacetone, phenylpyridine, picolinic acid, oxalate, and salen. The ligand L' is preferably represented by the above general formula [1-3].

[0074] In the general formula [1], the partial structure Ir(L') n can also be represented by the following general formula [1-3'] or [1-4']. Partial structure Ir(L') n is preferably a partial structure represented by the general formula [1-3'].

[0075] [ka]

[0076] [ka]

[0077] In the general formula [1-3] or [1-3'], R15 ~R 17 are each independently selected from a hydrogen atom, a deuterium atom, an alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group.

[0078] In the general formula [1-4] or [1-4'], R 32 ~R 39 are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, an alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. 32 ~R 39 may be joined together to form a ring.

[0079] R 15 ~R 17 or R 32 ~R 39 The alkyl group represented by the formula [1-1] and [1-2] is R2 to R 14 and R 18 ~R 21 The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms, more preferably an alkyl group having 1 to 6 carbon atoms, and even more preferably a methyl group or a tert-butyl group.

[0080] R 15 ~R 17 or R 32 ~R 39 Specific examples of the alkoxy group represented by the formula [1-1] and [1-2] are R to R 14 and R 18 ~R 21 The specific examples of the alkoxy group are the same as those of the alkoxy group represented by the following formula: Preferably, it is a methoxy group.

[0081] R 15 ~R 17 or R 32 ~R 39 Specific examples of the substituted amino group represented by the formula [1-1] and [1-2] are R2 to R 14 and R18 ~R 21 The examples are the same as those of the substituted amino group represented by the following formula: Preferably, it is an N,N-dimethylamino group or an N,N-diphenylamino group.

[0082] R 15 ~R 17 or R 32 ~R 39 Specific examples of the aryl group represented by the formula [1-1] and [1-2] are R2 to R 14 and R 18 ~R 21 The aryl group is preferably a phenyl group, a naphthyl group, a fluorenyl group or a biphenyl group, and more preferably a phenyl group.

[0083] R 15 ~R 17 or R 32 ~R 39 Specific examples of the heterocyclic group represented by the formula [1-1] and [1-2] include R to R 14 and R 18 ~R 21 The specific examples of the heterocyclic group represented by the following formula are the same as those of the heterocyclic group represented by the following formula.

[0084] R 15 ~R 17 or R 32 ~R 39 When any of R to R is an aryl group or a heterocyclic group, it may further have a substituent. The substituents that the aryl group and the heterocyclic group may further have are R to R in the general formulas [1-1] and [1-2]. 14 and R 18 ~R 21 This is the same as in the case of

[0085] The substituents that the alkyl group, aryl group, and heterocyclic group may further have are not particularly limited, and are the same as the substituents that the alkyl group, aryl group, and heterocyclic group in general formulas [1-1] and [1-2] may further have.

[0086] In this embodiment, R represented by any one of general formulas [1-3], [1-4], [1-3'], and [1-4'] 15 ~R 17 or R 32 ~R 39 is preferably a substituent selected from a hydrogen atom and an alkyl group having 1 to 10 carbon atoms, and more preferably a substituent selected from a hydrogen atom, a methyl group, and a tert-butyl group.

[0087] <Compound represented by general formula [3]>

[0088] [ka]

[0089] In the general formula [3], Ir is iridium. L, L', and L" represent different bidentate ligands. The partial structure Ir(L) is a partial structure represented by the following general formula [3-1] or [3-2], L' is a bidentate ligand represented by the above general formula [1-3], and L" is a bidentate ligand represented by the above general formula [1-4].

[0090] [ka]

[0091] [ka]

[0092] The substituents R1 to R2 of the ligands and partial structures of the general formula [3] are 14 and R 18 ~R 21 , R 15 ~R 17 , R 32 ~R 39 is the same as the compound represented by general formula [1], so the explanation will be omitted.

[0093] <Method for synthesizing iridium complexes> Next, a method for synthesizing the iridium complex represented by general formula [1] or [3] will be described. The iridium complex represented by general formula [1] or [3] can be synthesized, for example, via the processes shown in (I) and (II) below. (I) Synthesis of organic compounds to be used as ligands (II) Synthesis of organometallic complexes

[0094] Here, the processes (I) and (II) are similar to the methods described in, for example, Patent Documents 1 to 3.

[0095] Furthermore, when an iridium complex represented by general formula [1] or [3] is used as a constituent material of an organic light-emitting device, it is preferable to perform sublimation purification immediately before the process. Sublimation purification has a significant purification effect, thereby achieving high purity of the organic compound. However, the higher the molecular weight of the organic compound, the higher the temperature required for sublimation purification, which is prone to thermal decomposition due to high temperatures. Therefore, the molecular weight of the organic compound used as a constituent material of an organic light-emitting device is preferably 1200 or less, and more preferably 1100 or less, so that sublimation purification can be performed without excessive heating.

[0096] <Second compound (host molecule)> Next, the second compound, which is one of the constituent materials of the organic light-emitting device of this embodiment, will be described. The second compound, which is one of the constituent materials of the organic light-emitting device of this embodiment, is preferably a compound represented by the following general formula [2]. In this embodiment, the second compound is preferably contained as a host in the light-emitting layer of the organic light-emitting device. In this embodiment, the second compound is characterized by being composed of a hydrocarbon aromatic ring or heterocycle that does not have an alkyl group.

[0097] [ka]

[0098] In the general formula [2], p and q are each independently 0, 1, or 2, and satisfy the following relational expression. 0≦p+q≦4

[0099] In general formula [2], Ar1 to Ar4 are each independently selected from benzene, naphthalene, phenanthrene, chrysene, triphenylene, picene, fluoranthene, and compounds represented by the following general formula [2-1], each of which does not have an alkyl group as a substituent, and at least one of Ar1 to Ar4 is phenanthrene, chrysene, triphenylene, picene, fluoranthene, or a compound represented by the general formula [2-1]. Ar1 to Ar4 may each independently be selected from benzene, naphthalene, phenanthrene, chrysene, triphenylene, picene, and fluoranthene, each of which does not have an alkyl group as a substituent.

[0100] [ka]

[0101] In the general formula [2-1], Q represents an oxygen atom, a sulfur atom, or a nitrogen atom. When Q is a nitrogen atom, Q may have an aryl group or a heterocyclic group as a substituent.

[0102] Ring B1 and ring B2 are each independently selected from a hydrocarbon aromatic ring and a heterocyclic ring. Ring B1 and ring B2 may further have a substituent. Furthermore, adjacent Q, ring B1, and ring B2 may form a ring directly or indirectly via a substituent. Ring B1 and ring B2 may be the same or different.

[0103] Specific examples of ring B1 and ring B2 include aromatic hydrocarbon groups such as a phenyl group, a naphthyl group, a phenanthryl group, an acenaphthylenyl group, a chrysenyl group, a triphenylenyl group, a picenyl group, a fluoranthenyl group, a biphenyl group, and a terphenyl group; heteroaromatic groups such as a thienyl group, a pyrrolyl group, a pyrazinyl group, a pyridyl group, an indolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an acridinyl group, and a phenanthrolinyl group; and carbazolyl groups, benzo[a]carbazolyl groups, benzo[b]carbazolyl groups, benzo[c]carbazolyl groups, phenazinyl groups, phenoxazinyl groups, phenothiazinyl groups, benzothiophenyl groups, dibenzothiophenyl groups, benzofuranyl groups, dibenzofuranyl groups, oxazolyl groups, and oxadiazolyl groups.

[0104] The heterocycle-containing compound represented by the general formula [2-1] is preferably any one of the compounds shown in the following Group A1.

[0105] [ka]

[0106] Furthermore, it is particularly preferable that the second compound is any of the compounds represented by the following general formulas [8] to

[13] .

[0107] [ka]

[0108] In the general formulas [8] to

[13] , Ar5 and Ar6 are each independently selected from benzene, naphthalene, phenanthrene, chrysene, triphenylene, picene, fluoranthene, and compounds represented by the general formula [2-1] above, which do not have an alkyl group as a substituent.

[0109] In the general formulas [8] to

[13] , E1 to E 24 are independently selected from a hydrogen atom and a substituted or unsubstituted aromatic hydrocarbon group, provided that E1 to E 24does not have an alkyl group as a substituent. 24 Examples of substituents that may further be possessed by the aromatic hydrocarbon group represented by the formula (I) include aromatic hydrocarbon groups such as phenyl, naphthyl, phenanthryl, acenaphthylenyl, chrysenyl, triphenylenyl, picenyl, fluoranthenyl, biphenyl, and terphenyl; heteroaromatic groups such as thienyl, pyrrolyl, pyrazinyl, pyridyl, indolyl, quinolyl, isoquinolyl, naphthyridinyl, acridinyl, and phenanthrolinyl; carbazolyl, benzo[a]carbazolyl, benzo[b]carbazolyl, benzo[c]carbazolyl, phenazinyl, phenoxazinyl, phenothiazinyl, benzothiophenyl, dibenzothiophenyl, benzofuranyl, dibenzofuranyl, oxazolyl, and oxadiazolyl; and cyano groups. 24 The substituent that the aromatic hydrocarbon group represented by the following formula (I) may further have is preferably a phenyl group, a naphthyl group, a fluorenyl group, a biphenyl group or a terphenyl group.

[0110] In the general formulae [8] to

[13] , r represents an integer of 0 to 4. Preferably, r is 1. When r is 2 or more, multiple Ar5s may be the same or different from each other.

[0111] Thus, the compounds represented by the general formulas [8] to

[13] are preferred as the second compound for the following reasons. First, it is thought that among heterocyclic compounds, thiophene derivatives are more stable than furan derivatives among five-membered ring compounds, and xanthene derivatives are more stable than thioxanthene derivatives among six-membered ring compounds. Second, it is thought that the presence of substituents at highly chemically reactive sites (ortho and para positions relative to the oxygen and sulfur atoms) in the (aromatic) heterocyclic skeleton increases chemical stability.

[0112] Furthermore, it is desirable to purify each compound used as a constituent material of the organic light-emitting device of this embodiment in advance. Sublimation purification is a preferred method for purifying compounds. This is because sublimation purification is highly effective in purifying organic compounds. Generally, in sublimation purification, the higher the molecular weight of the organic compound to be purified, the higher the heating temperature required, which is prone to thermal decomposition due to high temperatures. Therefore, organic compounds used as constituent materials of organic light-emitting devices preferably have a molecular weight of 1500 or less so that sublimation purification can be performed without excessive heating. On the other hand, for a given molecular weight, compounds with smaller π-conjugated planes in their molecular skeletons have relatively smaller intermolecular interactions and are therefore more likely to sublimate, making them advantageous for sublimation purification. Conversely, compounds with larger π-conjugated planes in their molecular skeletons have (relatively) larger intermolecular interactions and are therefore less likely to sublimate, making them disadvantageous for sublimation purification.

[0113] On the other hand, if the molecular weight is too small, the deposition rate becomes unstable during vacuum deposition, which is particularly noticeable when the second compound is used as a host.

[0114] Therefore, in consideration of the balance of molecular weight and the size of the π-conjugated plane described above, in the heterocycle-containing compounds represented by the general formulas [8] to

[13] , p is preferably 1. Furthermore, although it is in consideration of the chemical stability, E1 to E 24 are all hydrogen atoms, the molecular weight is reduced, and this is more preferable.

[0115] Furthermore, among the compounds represented by general formula [2], those in which the largest dihedral angle formed by any two adjacent pairs of Ar1 to Ar4 is 26 degrees (deg) or less are preferred. In other words, the second compound preferably has a highly planar molecular structure. When the second compound has a highly planar molecular structure, triplet excitons can be efficiently diffused within the layer containing the second compound. As a result, exciton annihilation between triplet excitons is suppressed, and driving durability can be further improved.

[0116] Table 1 shows the molecular structures of exemplary compounds suitable as the second compound, the largest dihedral angle (maximum dihedral angle) formed by two adjacent pairs of Ar1 to Ar4 in each exemplary compound, and the ratio of the driving durability of organic light-emitting devices using each exemplary compound as a host. Regarding the configuration of the organic light-emitting device in the case of exemplary compound L-104, the configurations of Example 2 and Comparative Example 2 described below were used, and the ratio of the half-life (half-life) of Example 2 to the half-life (half-life) of Comparative Example 2 is shown as the driving durability ratio. The other exemplary compounds and comparative compounds were similar except that the host was replaced with the respective exemplary compounds or comparative compounds. The dihedral angles were calculated by molecular orbital calculations using Chem3D's MM2.

[0117] [Table 1]

[0118] As shown in Table 1, when the second compound has a maximum dihedral angle of 26 degrees or less, it exhibits particularly good driving durability when combined with the first compound of this embodiment. That is, by using a second compound having a high degree of planarity, with a maximum dihedral angle of 26 degrees or less, in the light-emitting layer together with the first compound represented by the general formula [1], the driving durability of the organic light-emitting device can be significantly improved.

[0119] Furthermore, the comparative compound R-101, which contains an alkyl group as a substituent, has a small maximum dihedral angle of 4°, but does not have the effect of improving durability as will be described later.

[0120] <Actions and effects brought about by the first compound and the second compound> In the organic light-emitting device of this embodiment, the organic compound layer (e.g., the light-emitting layer) contains an iridium complex (first compound) represented by general formula [1] or [3]. Alternatively, the organic compound layer contains an iridium complex (first compound) represented by general formula [1] and a second compound represented by general formula [2].

[0121] The iridium complex represented by general formula [1] or [3] is an organometallic complex in which at least one aryl-naphtho[2,1-f]isoquinoline ligand or aryl-phenanthro[2,1-f]isoquinoline ligand is coordinated to iridium metal. The iridium complex of this embodiment is a red-emitting phosphorescent material with a high luminescence quantum yield. Here, red luminescence refers to emission with a peak emission wavelength in the range of 580 nm to 650 nm. Alternatively, the lowest triplet excitation level (T1) refers to emission in the range of 1.9 eV to 2.1 eV.

[0122] As shown in the examples below, organic light-emitting devices containing an iridium complex having an aryl-naphtho[2,1-f]isoquinoline ligand or an aryl-phenanthro[2,1-f]isoquinoline ligand as a guest in the light-emitting layer have very high luminous efficiency. Furthermore, it has been found that when R1 in general formula [1-1] or [1-2] has a substituent other than a hydrogen atom, the half-width of the emission spectrum is further narrowed, thereby improving color purity.

[0123] Furthermore, as a result of extensive research, the present inventors have found that when the iridium complex represented by general formula [1] is incorporated into the light-emitting layer together with the second compound represented by general formula [2], the driving durability is specifically improved. This effect is explained below.

[0124] In order to more effectively use the iridium complex of this embodiment, the inventors investigated a second compound as a host material suitable for use together with the iridium complex in the light-emitting layer. The inventors found that the driving durability of organic light-emitting devices can be improved by designing the molecules of the host material while focusing on the following points. (I) The host material does not have an alkyl group and has a fused ring skeleton of three or more rings. (II) Iridium complexes have sterically hindering groups in the vicinity of the iridium atom of the ligand.

[0125] In other words, two factors that are thought to be the cause of brightness degradation, (i) exciton annihilation between triplet excitons, which leads to deterioration of the light-emitting layer material, and (ii) host degradation due to bond dissociation, are suppressed, thereby extending the lifespan (improving driving durability) of organic light-emitting devices.

[0126] (I) The host material does not have an alkyl group and has a fused ring skeleton of three or more rings. It is known that exciton annihilation due to triplet excitons generated by recombination in the light-emitting layer of a phosphorescent light-emitting device leads to a decrease in efficiency and driving durability. This is because triplet excitons have a longer excitation lifetime than singlet excitons and therefore exist for a longer period in the light-emitting layer, increasing the probability of triplet excitons colliding with each other.

[0127] The present inventors have discovered a method to reduce the probability of triplet exciton collisions by improving the planarity of the host molecules and shortening the intermolecular distance, which makes it easier for triplet excitons to diffuse.

[0128] Therefore, we designed molecules with a fused ring structure of three or more rings to improve planarity and without sterically hindering groups such as alkyl groups to shorten the intermolecular distance. Figure 1 is a schematic diagram summarizing the guest and host structures and the interaction between the guest and host in each organic light-emitting device of the Examples and Comparative Examples. As shown in Figure 1, when the same iridium complex was used as the guest, the host without an alkyl group (Example Compound L-104) shown in Comparative Example 3 exhibited higher driving durability than the host with an alkyl group (Comparative Compound R-101) shown in Comparative Example 1. This is because the host without an alkyl group (Example Compound L-104) had a shorter intermolecular distance (the distance between the second compounds in the light-emitting layer), allowing triplet excitons to diffuse more efficiently. This is thought to be because the efficient diffusion of triplet excitons prevented triplet excitons from remaining in the host and colliding with each other, resulting in exciton annihilation.

[0129] (II) Iridium complexes have sterically hindering groups in the vicinity of the iridium atom of the ligand. The phenylnaphtho[2,1-f]isoquinoline and phenylphenanthro[2,1-f]isoquinoline ligand skeletons have a structure in which a naphthalene ring or a phenanthrene ring is fused to a quinoline, resulting in an extended π-orbital conjugated surface. Therefore, they are prone to interact with other nearby molecules (especially the host material in the emissive layer). As a result, they may capture the charge of other molecules, such as the host material, to form a radical state, or form exciplexes with other molecules, such as the host material, which is thought to reduce the luminous efficiency and driving durability.

[0130] The present inventors have searched for a complex having the above-described ligand skeleton and a structure that suppresses interactions with other molecules in order to avoid the formation of radical states or exciplexes. As a result, they have found that the driving durability of an organic light-emitting device can be further improved by providing, among the ligands of an iridium complex, a steric hindrance group in the vicinity of the iridium atom.

[0131] As shown in FIG. 1 , the iridium complex in Comparative Example 4 does not have a methyl group, which acts as a sterically hindering group, near the iridium atom of the ligand. Therefore, the distance between the iridium atom and the host is short. As a result, in Comparative Example 4, interactions between the iridium complex and the host are likely to occur, exciplexes and radical states are likely to be formed, and the luminous efficiency and driving durability are reduced. On the other hand, in Example 2, which uses the compound of this embodiment, the ligand in the iridium complex has a methyl group, which acts as a sterically hindering group, near the iridium atom. Therefore, the distance between the iridium atom and the host is long. As a result, in Example 2, interactions between the iridium complex and the host are suppressed, and the formation of exciplexes and radical states can be suppressed, resulting in improved luminous efficiency and driving durability.

[0132] As described above, in this embodiment, by having the above features (I) and (II), it is possible to control triplet excitons, exciplexes, and radical states, thereby improving driving durability.

[0133] The substituent of R1 in the general formulas [1-1] and [1-2] is preferably a methyl group. This is because if the substituent of R1 is too large, it interferes with other ligands in the molecule, distorting the structure of the complex and reducing the thermal stability of the complex. Therefore, from the viewpoint of achieving both the thermal stability of the complex and suppressing interaction with other molecules such as the host material, R1 is preferably a methyl group.

[0134] Furthermore, as a result of extensive investigation, it was found that, as shown in Table 2, when R3 is a phenyl group, the emission spectrum is narrowed, which is preferable.

[0135] However, when R3 is an aryl group or a heterocyclic group, the molecular weight of the iridium complex may become too large. If the molecular weight becomes too large, decomposition may occur during sublimation. Therefore, when R3 is an aryl group or a heterocyclic group, R2 to R 13 and R 18 ~R 21 It is preferable to introduce a substituent that suppresses intermolecular stacking into either of the above. This suppresses intermolecular stacking and improves sublimation. Examples of substituents that suppress intermolecular stacking include an i-propyl group, a tert-butyl group, a fluorine group, and a fluorine-substituted alkyl group, but are not limited to these as long as they are capable of suppressing intermolecular stacking. As shown in Table 2, exemplary compound K-106 substituted with a tert-butyl group and exemplary compound K-109 substituted with a fluorine group did not decompose during sublimation. Furthermore, as mentioned above, comparative compound 2-b, in which R1 is substituted with a sterically bulky i-propyl group, is not preferred because of its reduced thermal stability.

[0136] Furthermore, after extensive research, we found that the use of phenanthro[2,1-f]isoquinoline ligands can narrow the emission spectrum without introducing a phenyl group at the R3 position. That is, in the general formula [1] or [3], the partial structure Ir(L) m It has been found that when the partial structure represented by the general formula [1-2] is used, the emission spectrum is narrowed further.

[0137] [Table 2]

[0138] <<Specific Examples of the First Compound (Iridium Complex)>> Specific examples of the first compound are shown below.

[0139] [ka]

[0140] [ka]

[0141] [ka]

[0142] [ka]

[0143] [ka]

[0144] [ka]

[0145] [ka]

[0146] [ka]

[0147] [ka]

[0148] <<Specific Examples of the Second Compound>> Specific examples of the second compound are shown below.

[0149] [ka]

[0150] [ka]

[0151] [ka]

[0152] [ka]

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156]

change

[0157]

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[0158]

change

[0159]

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[0160]

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[0161]

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[0162]

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[0163]

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[0164]

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[0165]

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[0166]

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[0167] [ka]

[0168] Other ingredients As described above, the organic light-emitting device of this embodiment contains at least a first compound represented by the general formula [1] or [3] in the light-emitting layer. Alternatively, the organic light-emitting device of this embodiment contains at least a first compound represented by the general formula [1] and a second compound represented by the general formula [2] in the light-emitting layer. However, in addition to these compounds, conventionally known low-molecular-weight and high-molecular-weight materials can be used in combination with each layer constituting the organic light-emitting device of this embodiment, as needed. More specifically, a hole injection / transport material, a host, a light-emission assist material, an electron injection / transport material, or the like can be used together with each compound.

[0169] <Layers Constituting Organic Light-Emitting Device> Next, other layers constituting the organic light-emitting device of this embodiment will be described. As described above, the organic light-emitting device of this embodiment has at least a pair of electrodes (anode and cathode) and an organic compound layer disposed between these electrodes. The organic compound layer may be a single layer or a laminate consisting of multiple layers, as long as it has an emitting layer. In the above embodiment, the case where the emitting layer of the organic compound layer contains the first compound has been described, but the first compound may be contained in a layer other than the emitting layer.

[0170] The present inventors have conducted various studies and found that using the first compound according to this embodiment as a host or guest in the light-emitting layer, particularly as a guest in the light-emitting layer, results in a device that exhibits high-efficiency, high-brightness light output and is extremely durable. This light-emitting layer may be a single layer or multiple layers, and it is possible to mix the red light emitted by this embodiment with a light-emitting material having another light-emitting color. "Multiple layers" refers to a state in which the light-emitting layer and another light-emitting layer are stacked. In this case, the light-emitting color of the organic light-emitting device is not limited to red. More specifically, it may be white or a neutral color. In the case of white, the other light-emitting layer emits a color other than red, i.e., blue or green. Furthermore, the film is formed by vapor deposition or coating. Details of this will be explained in detail in the examples below.

[0171] The first compound according to this embodiment 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 red. More specifically, it may emit white light or an intermediate color.

[0172] In addition to the organic compound according to this embodiment, 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.

[0173] As the hole injection / transport material, a material with high hole mobility is preferred, facilitating the injection of holes from the anode and transporting the injected holes to the light-emitting layer. Furthermore, a material with a high glass transition temperature is preferred to suppress 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 / 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 / transport materials are also suitable for use in electron blocking layers. Specific examples of compounds that can be used as hole injection / transport materials are listed below, but of course, the present invention is not limited to these.

[0174] [ka]

[0175] Examples of luminescent materials mainly involved in the luminescence function include the first compound represented by general formula [1] or [3], as well as 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.

[0176] Specific examples of compounds that can be used as light-emitting materials are shown below, but the present invention is not limited to these.

[0177] [ka]

[0178] [ka]

[0179] Examples of the light-emitting layer host or light-emitting assist material other than the second compound 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.

[0180] Specific examples of compounds that can be used as the light-emitting layer host or light-emitting assist material other than the second compound contained in the light-emitting layer are shown below, but the present invention is not limited to these.

[0181] [ka]

[0182] 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.

[0183] [ka]

[0184] The following describes the components other than the organic compound layer that make up the organic light-emitting device of this embodiment. The organic light-emitting device may be provided by forming a first electrode, an organic compound layer, and a second electrode on a substrate. One of the first electrode and the second electrode is an anode and the other is a cathode. A protective layer, a color filter, etc. may be provided on the second electrode. When a color filter is provided, a planarizing layer may be provided between the protective layer and the color filter. The planarizing layer may be made of acrylic resin, etc.

[0185] The substrate may be made of quartz, glass, silicon, resin, metal, or the like. Furthermore, a switching element such as a transistor and wiring may be provided on the substrate, and an insulating layer may be provided thereon. The insulating layer may be made of any material, as long as it can form a contact hole to ensure electrical continuity between the anode and the wiring and can ensure insulation from unconnected wiring. For example, resins such as polyimide, silicon oxide, silicon nitride, or the like may be used.

[0186] The anode material should preferably have a high work function. Examples include 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. These electrode materials can be used alone or in combination. The anode may be composed of a single layer or multiple layers. When used as a reflective electrode, materials such as chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates of these materials can be used. 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 can be used to form the anode.

[0187] 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 suppress silver aggregation. The alloy ratio is not critical as long as silver aggregation can be suppressed. For example, a 1:1 ratio is acceptable.

[0188] 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.

[0189] A protective layer may be provided after the cathode is formed. For example, by adhering glass provided with a moisture absorbent onto the cathode, it is possible to prevent water and other substances from penetrating the organic compound layer, thereby suppressing display defects. In another embodiment, a passivation film such as silicon nitride may be provided on the cathode to prevent water and other substances from penetrating the organic compound layer. For example, after the cathode is formed, the device may be transported to another chamber without breaking the vacuum, and a silicon nitride film with a thickness of 2 μm may be formed by CVD to serve as a protective layer. A protective layer may also be provided using atomic layer deposition (ALD) after the film is formed by CVD.

[0190] Alternatively, a color filter may be provided for each pixel. For example, a color filter matching the size of the pixel 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 a protective layer such as silicon oxide using photolithography.

[0191] 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 this embodiment can be formed by the following methods. That is, to form the organic compound layers, dry processes such as vacuum deposition, ionization deposition, sputtering, and plasma can be used. Alternatively, instead of 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 (e.g., spin coating, dipping, casting, LB method, inkjet method, etc.). Here, when a layer is formed by a vacuum deposition method or solution coating method, crystallization and the like are unlikely to occur and the layer has excellent stability over time. Furthermore, when a film is formed by a coating method, a film can be formed by combining it with an appropriate binder resin. Examples of binder resins include, but are not limited to, polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin. The binder resin may be a homopolymer or a copolymer, and may be used singly or in combination of two or more kinds. If necessary, known additives such as plasticizers, antioxidants, and ultraviolet absorbers may be used in combination.

[0192] <Device using organic light-emitting element> 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.

[0193] The display device may be an image information processing device having an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., 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. In this case, the substrate may be a semiconductor substrate such as silicon, and the transistor may be a MOSFET formed on the substrate.

[0194] 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.

[0195] Next, the display device according to this embodiment will be described with reference to the drawings.

[0196] 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).

[0197] FIG. 2(a) shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel has 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 has a reflective electrode 2, which serves as a first electrode, on an interlayer insulating layer 1, an insulating layer 3 covering the edge of the reflective electrode 2, an organic compound layer 4 covering the first electrode and the insulating layer, a transparent electrode 5, a protective layer 6, and a color filter 7.

[0198] A transistor and a capacitor may be disposed below or inside the interlayer insulating layer 1. The transistor and the first electrode may be electrically connected via a contact hole or the like (not shown).

[0199] The insulating layer 3 is also called a bank or pixel separation film. It covers the edges of the first electrode and surrounds the first electrode. The part where the insulating layer is not provided contacts the organic compound layer 4 and becomes the light-emitting region.

[0200] 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 .

[0201] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0202] The protective layer 6 reduces the penetration of moisture into the organic compound layer. Although the protective layer is illustrated as a single layer, it may be a multi-layer. Each layer may be an inorganic compound layer and an organic compound layer.

[0203] The color filters 7 are divided into 7R, 7G, and 7B depending on their colors. The color filters may be formed on a planarization film (not shown). A resin protective layer (not shown) may be provided on the color filters. The color filters may be formed on a protective layer 6. Alternatively, the color filters may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0204] The display device 100 in Fig. 2(b) has an organic light-emitting element 26 and a TFT 18, which is 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 of the active element, a gate insulating film 14, and a semiconductor layer 15 are provided.

[0205] The TFT 18 has a semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is provided on the top of the TFT 18. An anode 21 constituting an organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20.

[0206] The electrical connection 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 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.

[0207] 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 25 and a second protective layer 24 are provided on the cathode 23 to suppress deterioration of the organic light-emitting element.

[0208] In the display device 100 of FIG. 2(b), transistors are used as switching elements, but other switching elements such as MIM elements may be used instead.

[0209] The transistors used in the display device 100 of Fig. 2(b) are not limited to thin-film transistors having an active layer on an insulating surface of a substrate, but may also be transistors using a single-crystal silicon wafer. 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.

[0210] 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.

[0211] 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.

[0212] 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.

[0213] The display device according to this embodiment may be used as a display unit of an imaging device having an optical unit with multiple 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 located within the viewfinder. The imaging device may be a digital camera or a digital video camera. The imaging device may also be referred to as a photoelectric conversion device.

[0214] 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.

[0215] 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.

[0216] 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.

[0217] 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.

[0218] The display device according to the present embodiment may be used as a display unit of an electronic device such as 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.

[0219] FIG. 4(b) is a schematic diagram showing 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 may be a biometric recognition unit that recognizes a fingerprint to perform operations such as unlocking. An electronic device having a communication unit can also be called a communication device.

[0220] 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 include a light-emitting device according to this embodiment. The display device 1300 has a base 1303 that supports the frame 1301 and the display unit 1302. The base 1303 is not limited to the form shown in FIG. 5(a). The bottom side of the frame 1301 may also serve as the base. The frame 1301 and the display unit 1302 may be curved so that the display surface of the display unit 1302 is curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0221] 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 a light-emitting device 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.

[0222] 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 film 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 may be a filter that improves the color rendering of the light source. The light diffusion unit can effectively diffuse light from the light source, such as for illumination, and deliver the light over a wide area. The optical filter and the light diffusion unit may be provided on the light emission side of the lighting. If necessary, a cover may be provided on the outermost part.

[0223] 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 for dimming them or a color tuning circuit for tuning the emitted color. The lighting device may have the organic light-emitting element of this embodiment and a power supply circuit connected to it. 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.

[0224] 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.

[0225] 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.

[0226] 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 EL element. The protective member may be made of any material as long as it has a certain degree of strength and is transparent, but it is preferably made of polycarbonate or the like. Polycarbonate may be mixed with a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like.

[0227] 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.

[0228] 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.

[0229] 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.

[0230] 7(a) illustrates glasses 1600 (smart glasses) according to one application example. 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. Furthermore, a display device according to any of the above-described embodiments is provided on the back side of the lens 1601.

[0231] 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 according to each embodiment. 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.

[0232] FIG. 7(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 include a control device 1612, which is equipped with an imaging device equivalent to the imaging device 1602 and a display device. A lens 1611 includes an optical system for projecting light emitted from the imaging device and the display device within the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power source for supplying power to the imaging device and the display device and controls the operation of the imaging device and the display device. The control device may also include a gaze detection unit for detecting the wearer's gaze. Infrared light may be used for gaze detection. The infrared light emitter emits infrared light toward the eyeball of a user gazing at a displayed image. An imaging unit with a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. A reduction unit for reducing light from the infrared light emitter to the display unit in a planar view reduces degradation of image quality.

[0233] The gaze of the user relative to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be used for gaze detection using an image of the eyeball. One example is a gaze detection method based on the Purkinje image formed by reflection of irradiated light on the cornea.

[0234] More specifically, gaze detection processing is performed based on the pupil-corneal reflex method, which calculates a gaze vector representing the direction (rotation angle) of the eyeball based on the pupil image and Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0235] A display device according to an embodiment of the present invention may have an imaging device having a light receiving element, and may control the image displayed on the display device based on information about the user's line of sight from the imaging device.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] 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.

[0240] FIG. 8 is a schematic diagram illustrating an example of an image forming apparatus according to this embodiment. 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 emitted from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoconductor 27. This 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.

[0241] 9(a) and 9(b) 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 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. 9(a) shows a configuration in which the light-emitting units 36 are arranged along the long axis direction of the photoconductor 27. FIG. 9(b) shows a different configuration from FIG. 9(a), 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. 9(b) can also be described as a grid arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0242] 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]

[0243] [Synthesis Examples 1 to 9 (Synthesis of Example Compounds)] The exemplary compounds were synthesized based on the synthesis processes described in Patent Documents 1 to 3. Table 3 shows the exemplary compounds synthesized in Synthesis Examples 1 to 6, and Table 4 shows the exemplary compounds synthesized in Synthesis Examples 1 to 6. The actual measured values ​​(m / z) of the mass spectrometry results are also shown.

[0244] [Table 3]

[0245] [Table 4]

[0246] [Example 1] 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.

[0247] 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 The organic compound layer and electrode layer shown in Table 5 were successively formed on the ITO substrate by vacuum deposition using resistance heating in a vacuum chamber at 1000 Pa. 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.

[0248] [Table 5]

[0249] The device characteristics were measured and evaluated. The device emitted red light with a luminous efficiency of 24 cd / A and a chromaticity of (X, Y) = (0.69, 0.32). Furthermore, at a current density of 100 mA / cm 2A continuous driving test was conducted at 1000 Hz, and the brightness half-life (LT50) was measured, resulting in a result of 430 hours.

[0250] 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.

[0251] [Examples 2 to 22, Comparative Examples 1 to 9] An organic light-emitting device was produced in the same manner as in Example 1, except that the materials forming each layer in Example 1 were appropriately changed to the compounds shown in Table 6. Layers not listed in Table 6 had the same configuration as in Example 1. The characteristics of the obtained device were measured and evaluated in the same manner as in Example 1. The measurement results are shown in Table 6, along with the measurement results of Example 1.

[0252] The structures of the comparative compounds R-101, KK-28, and KK-31 used in the comparative examples are shown below.

[0253] [ka]

[0254] [ka]

[0255] [Table 6]

[0256] Comparative Examples 3 and 4 are organic light-emitting devices using comparative compound R-101 as a host, and Comparative Examples 6 and 7 are organic light-emitting devices using comparative compound R-102. Both comparative compounds R-101 and R-102 are compounds containing an alkyl group. In this way, when a compound containing an alkyl group is used as a host, a compound represented by general formula [1] and having the partial structure Ir(L) mIt was found that even when a compound represented by general formula [1-5] and L' represented by general formula [1-3] is used as a guest, the effect of improving driving durability is not fully achieved. This is thought to be due to the fact that the alkyl group in the compound used as the host inhibits the interaction between the host and the iridium complex, as mentioned above. Therefore, the effect of suppressing the formation of exciplexes and radical states by suppressing the interaction between the host and the iridium complex by having a substituent other than hydrogen in R1 of general formula [1-1] is not fully achieved.

[0257] The luminance half-life was shorter in Comparative Example 1 than in Example 1, Comparative Example 2 than in Example 2, Comparative Example 5 than in Example 13, Comparative Example 8 than in Example 14, and Comparative Example 9 than in Example 15. The compound used as the host in these Examples and Comparative Examples is a compound represented by general formula [2] that does not have an alkyl group and has a fused ring skeleton of three or more rings. When such a compound is used as the host, it was found that the luminance half-life was shortened when an iridium complex having a partial structure in which R1 is hydrogen in general formula [1-1] or general formula [1-2] was used as the guest (Comparative Examples 1, 2, 5, 8, and 9). On the other hand, it was found that the luminance half-life was improved when an iridium complex having a partial structure in which R1 is a substituent other than hydrogen in general formula [1-1] or general formula [1-2] was used as the guest (Examples 1, 2, 13, 14, and 15). This is thought to be due to the fact that the substituent suppresses the interaction between the host and the iridium complex, suppressing the formation of exciplexes and radical states, as described above.

[0258] The maximum dihedral angle of the compounds used as hosts in Examples 1, 2, 13, 14, and 15 is as shown in Table 1. Tables 1 and 6 show that when the maximum dihedral angle of the compound used as a host (second compound) is 26 degrees or less, the driving durability is particularly high.

[0259] In other examples, good luminance half-life was obtained by using as a guest an iridium complex having a partial structure in which R1 in general formula [1-1] or general formula [1-2] is a substituent other than hydrogen. [Explanation of symbols]

[0260] 1. Organic light-emitting device 11 Circuit Board 21 Anode 22 Organic compound layer 23 Cathode

Claims

1. An organic light-emitting device having an anode, a cathode, and a light-emitting layer disposed between the anode and the cathode, The light-emitting layer comprises a first compound represented by the following general formula [1] and a second compound represented by the following general formula [2]: 【Chemical 1】 【Chemistry 2】 (In the general formula [1], Ir is iridium. L and L' represent different bidentate ligands. m is any one of 1 to 3, n is any one of 0 to 2, and m+n=3. Partial structure Ir(L) ｍ is a partial structure represented by the following general formula [1-1] or [1-2], and L' is a bidentate ligand represented by the following general formula [1-3] or [1-4]. 【Chemistry 3】 【Chemistry 4】 【Chemistry 5】 【Chemistry 6】 (In the general formula [1-1], R １ is any one of a fluorine atom, an alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, an aryl group, and a heterocyclic group. ２ ~R １４ and R １８ ~R ２１ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. １ ~R ４ may form a ring together. １５ ~R １７ are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ may be joined together to form a ring. (In the general formula [2], p and q each independently represent 0, 1, or 2, and satisfy the following relational expression: 0≦p+q≦4 In the general formula [2], Ar １ ~Ar ４ are each independently selected from benzene not having an alkyl group as a substituent, naphthalene, phenanthrene, chrysene, triphenylene, picene, fluoranthene, and a compound represented by the following general formula [2-1], and at least one is any of phenanthrene, chrysene, triphenylene, picene, fluoranthene, and a compound represented by the general formula [2-1]. 【Chemistry 7】 (In general formula [2-1], Q represents an oxygen atom, a sulfur atom, or a nitrogen atom, and ring B1 and ring B2 are each independently selected from a hydrocarbon aromatic ring and a heterocyclic ring. Ring B1 and ring B2 may have a substituent, and when Q is a nitrogen atom, Q may have an aryl group or a heterocyclic group as a substituent. Adjacent Qs, ring B1, and ring B2 may form a ring directly or via a substituent.)

2. In the general formulas [1-1] and [1-2], R １ The organic light-emitting element according to claim 1 , wherein is a methyl group.

3. In the general formulas [1-1] and [1-2], R ３ are each independently selected from an aryl group and a heterocyclic group; R ２ ~R １３ and R １８ ~R ２１ 3. The organic light-emitting device according to claim 2, wherein at least one of the groups is an i-propyl group, a tert-butyl group, a fluorine group, or a fluorine-substituted alkyl group.

4. In the general formula [2], Ar １ ~Ar ４ 4. The organic light-emitting element according to claim 1, wherein the largest dihedral angle formed by any two adjacent ones of the above is 26 degrees or less.

5. In the general formula [2], Ar １ ~Ar ４ are each independently selected from benzene, naphthalene, phenanthrene, chrysene, triphenylene, picene, and fluoranthene that do not have an alkyl group as a substituent, and at least one of them is phenanthrene, chrysene, triphenylene, picene, or fluoranthene. The organic light-emitting element according to any one of claims 1 to 4,

6. In the general formula [2], Ar １ ~Ar ４ The organic light-emitting device according to claim 5 , wherein at least one of the above is any one of the following Group A1: 【Chemistry 8】 (In the above Group A1, Q represents an oxygen atom, a sulfur atom, or a nitrogen atom. When Q is a nitrogen atom, Q may have an aryl group or a heterocyclic group.)

7. The organic light-emitting device according to any one of claims 1 to 6, wherein the second compound is a compound represented by any one of the following general formulas [8] to [13]: 【Chemistry 9】 (In the general formulas [8] to [13], r represents an integer of 0 to 4. Ar ５ and Ar ６ are each independently selected from benzene, naphthalene, phenanthrene, chrysene, triphenylene, picene, fluoranthene, and compounds represented by the general formula [2-1] that do not have an alkyl group as a substituent, and when r is 2 or more, a plurality of Ar ５ may be the same or different from each other. １ ~E ２４ are independently selected from a hydrogen atom and a substituted or unsubstituted aromatic hydrocarbon group. １ ~E ２４ does not have an alkyl group as a substituent.)

8. 8. The organic light-emitting element according to claim 1, wherein, in the light-emitting layer, a weight ratio of the second compound in the group of compounds contained in the light-emitting layer is larger than a weight ratio of the first compound in the group of compounds contained in the light-emitting layer.

9. An organometallic complex represented by the following general formula [1]: 【Chemistry 10】 (In the general formula [1], Ir is iridium. L and L' represent different bidentate ligands. m is 1 or 2, and when m is 1, n is 2, and when m is 2, n is 1.) ｍ is a partial structure represented by the following general formula [1-5], and L' is a bidentate ligand represented by the following general formula [1-4]. 【Chemistry 11】 【Chemistry 12】 (In the general formula [1-5], R ２ ~R １４ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ２ ~R ４ may form a ring together. ３２ ~R ３９ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ may be joined together to form a ring.)

10. An organometallic complex represented by the following general formula [3]: 【Chemistry 13】 In the general formula [3], Ir is iridium. L, L', and L" represent different bidentate ligands. The partial structure Ir(L) is a partial structure represented by the following general formula [3-1], L' is a bidentate ligand represented by the following general formula [1-3], and L" is a bidentate ligand represented by the following general formula [1-4]. 【Chemistry 14】 【Chemistry 15】 【Chemistry 16】 (In the general formula [3-1], R ２ ~R １４ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ２ ~R ４ may form a ring together. １５ ~R １７ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ may be joined together to form a ring.

11. An organometallic complex represented by the following general formula [1]: 【Chemistry 17】 (In the general formula [1], Ir is iridium. L and L' represent different bidentate ligands. m is 1 or 2, and when m is 1, n is 2, and when m is 2, n is 1.) ｍ is a partial structure represented by the following general formula [1-2], and L' is a bidentate ligand represented by the following general formula [1-3] or [1-4]. 【Chemistry 18】 【Chemistry 19】 【Chemistry 20】 (In the general formula [1-2], R １ are each independently selected from a fluorine atom, an alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, an aryl group, and a heterocyclic group. ２ ~R １４ and R １８ ~R ２１ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. １ ~R ４ may form a ring together. １５ ~R １７ are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ may be joined together to form a ring.

12. An organometallic complex represented by the following general formula [3]: 【Chemical 21】 In the general formula [3], Ir is iridium. L, L', and L" represent different bidentate ligands. The partial structure Ir(L) is a partial structure represented by the following general formula [3-2], L' is a bidentate ligand represented by the following general formula [1-3], and L" is a bidentate ligand represented by the following general formula [1-4]. 【Chemical 22】 【Chemical 23】 【Chemistry 24】 (In the general formula [3-2], R １ are each independently selected from a fluorine atom, an alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, an aryl group, and a heterocyclic group. ２ ~R １４ and R １８ ~R ２１ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. １ ~R ４ may form a ring together. １５ ~R １７ are each independently selected from a hydrogen atom, a deuterium atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ are each independently selected from a hydrogen atom, a deuterium atom, a fluorine atom, a substituted or unsubstituted alkyl group, a deuterium-substituted alkyl group, an alkoxy group, a silyl group, a substituted amino group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group. ３２ ~R ３９ may be joined together to form a ring.

13. An organic light-emitting device having an anode, a cathode, and a light-emitting layer disposed between the anode and the cathode, An organic light-emitting device, wherein the light-emitting layer comprises the organometallic complex according to any one of claims 9 to 12.

14. 14. The organic light-emitting device according to claim 1, which emits red light.

15. the light-emitting layer is a first light-emitting layer, a second light-emitting layer different from the first light-emitting layer is further provided between the first light-emitting layer and the anode or between the first light-emitting layer and the cathode; 14. The organic light-emitting element according to claim 1, wherein the second light-emitting layer emits light of a color different from that of the light emitted by the first light-emitting layer.

16. The organic light-emitting device according to claim 15, which emits white light.

17. having a plurality of pixels, A display device, wherein at least one of the plurality of pixels comprises the organic light-emitting element according to any one of claims 1 to 8 and 13 to 16, and an active element connected to the organic light-emitting element.

18. 18. The display device according to claim 17, further comprising a color filter.

19. 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 display unit comprises the organic light-emitting element according to any one of claims 1 to 8 and 13 to 16.

20. The device has a housing, a communication unit that communicates with the outside, and a display unit, 17. An electronic device, wherein the display unit comprises the organic light-emitting element according to claim 1.

21. An illumination device having a light source and a light diffusion unit or an optical filter, 17. A lighting device, wherein the light source comprises the organic light-emitting element according to claim 1.

22. 17. 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 from the light source.

23. 23. The lighting device of claim 22, further comprising a color filter.

24. A drone includes a body and a lighting fixture provided on the body, A moving body, wherein the lighting device comprises the organic light-emitting element according to any one of claims 1 to 8 and 13 to 16.

25. An exposure light source for an electrophotographic image forming apparatus, comprising the organic light emitting device according to any one of claims 1 to 8 and 13 to 16.

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