Organic light-emitting element and various devices using the same

Abstract

To provide an organic light-emitting element which shows a lower driving voltage.SOLUTION: An organic light-emitting element sequentially includes: a first electrode 200; a first light-emitting unit 300; a charge generation layer 400; a second light-emitting unit 500; and a second electrode 600, the second light-emitting unit including, in this order from the first electrode side: a first organic layer 502, a first light-emitting layer 503, and a second organic layer 504, the first organic layer including a first compound, the first light-emitting layer including a second compound and a third compound, the second organic layer including a fourth compound. The first compound and the second compound satisfy the relationship (a), HOMO(B)-HOMO(A)≥0 eV, where HOMO(A) and HOMO(B) respectively represent the HOMO energy levels of the first compound and the second compound.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an organic light-emitting element and various devices using the same. [Background technology]

[0002] An organic electroluminescence element (hereinafter also referred to as an "organic EL element" or "organic light-emitting element") is an element that emits light when electricity is passed through an organic compound layer that includes an anode, a cathode, and a light-emitting layer disposed between these electrodes.

[0003] In recent years, in addition to monochromatic organic light-emitting devices that emit white light by having red, green, and blue light-emitting materials in a single light-emitting layer, stacked organic light-emitting devices have been developed in which light-emitting layers that emit red, green, and blue light are stacked. Because stacked organic light-emitting devices tend to have higher driving voltages than single-layer organic light-emitting devices, a structure in which an intermediate layer called a charge generation layer or intermediate electrode is provided is known. Intermediate layers tend to deteriorate more easily than other organic layers. Deterioration of the intermediate layer leads to higher driving voltages, lower efficiency, and reduced durability, so there is a demand for the development of stable stacked organic light-emitting devices.

[0004] Patent Documents 1 and 2 disclose stacked organic light-emitting devices having a charge generating layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-117963 [Patent Document 2] Japanese Patent Publication No. 2023-029747 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the organic light-emitting device described in Patent Document 1 has a configuration in which two light-emitting layers easily trap electrons. Furthermore, the organic light-emitting device described in Patent Document 2 has a configuration in which one light-emitting layer easily traps electrons and the other light-emitting layer easily traps holes. As described above, the organic light-emitting devices described in Patent Documents 1 and 2 do not take into consideration the relationship between the HOMO energy level and the LUMO energy level of each light-emitting layer and the compounds contained in the surrounding layers, and do not sufficiently consider the carrier injection property into each light-emitting layer. Therefore, the organic light-emitting devices described in Patent Documents 1 and 2 have room for improvement in terms of driving voltage.

[0007] The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic light-emitting element that exhibits a low driving voltage. [Means for solving the problem]

[0008] The organic light-emitting device according to the present invention is an organic light-emitting device having a first electrode, a first light-emitting unit, a charge generation layer, a second light-emitting unit, and a second electrode in this order, and the second light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer, in this order from the first electrode side, the first organic layer has a first compound, the first light-emitting layer has a second compound and a third compound, and the second organic layer has a fourth compound, and is characterized in that the first compound and the second compound satisfy the relationship (a). (a) HOMO(B)-HOMO(A)≧0 eV HOMO(A) and HOMO(B) represent the HOMO energy levels of the first compound and the second compound, respectively. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an organic light-emitting device that exhibits a lower driving voltage. [Brief explanation of the drawings]

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

[0011] In this specification, examples of halogen atoms include, but are not limited to, fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc. Among these, fluorine atoms are preferred.

[0012] Examples of alkali metal atoms include, but are not limited to, lithium, sodium, potassium, rubidium, and cesium atoms, with lithium and cesium atoms being preferred.

[0013] Examples of alkaline earth metal atoms include, but are not limited to, beryllium atoms, magnesium atoms, calcium atoms, and strontium atoms.

[0014] The alkyl group may be an alkyl group having 1 to 20 carbon atoms. Specific examples include, but are not limited to, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, an isopentyl group, a tert-pentyl group, a neopentyl group, an n-hexyl group, an octyl group, a cyclohexyl group, a 1-adamantyl group, and a 2-adamantyl group. The alkyl group preferably has 1 to 10 carbon atoms, and more preferably has 1 to 6 carbon atoms. Specific examples include a methyl group or a tert-butyl group.

[0015] The alkoxy group may be an alkoxy group having 1 to 10 carbon atoms. Specific examples include, but are not limited to, a methoxy group, an ethoxy group, an n-propoxy group, an iso-propoxy group, an n-butoxy group, a tert-butoxy group, a 2-ethyl-octyloxy group, and a benzyloxy group. The alkoxy group preferably has 1 to 4 carbon atoms. Specifically, a methoxy group is preferred.

[0016] The aryl group may be an aryl group having from 6 to 30 carbon atoms. Specific examples include, but are not limited to, 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, a ter-phenyl group, a phenylene group, a naphthylene group, a phenanthrenylene group, a biphenyl group, a fluoranthenylene group, a chrysenylene group, and a pyrenylene group.

[0017] The heterocyclic group may be a heterocyclic group having 3 to 27 carbon atoms. Specific examples include, but are not limited to, 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.

[0018] Specific examples of the silyl group include, but are not limited to, a trimethylsilyl group and a triphenylsilyl group.

[0019] Specific examples of the amino group include, but are not limited to, N-methylamino, N-ethylamino, N,N-dimethylamino, N,N-diethylamino, N-methyl-N-ethylamino, N-benzylamino, N-methyl-N-benzylamino, N,N-dibenzylamino, anilino, N,N-diphenylamino, N,N-dinaphthylamino, N,N-difluorenylamino, N-phenyl-N-tolylamino, N,N-ditolylamino, N-methyl-N-phenylamino, N,N-dianisolylamino, N-mesityl-N-phenylamino, N,N-dimesitylamino, N-phenyl-N-(4-tert-butylphenyl)amino, and N-phenyl-N-(4-trifluoromethylphenyl)amino. The amino group is preferably an N,N-dimethylamino or N,N-diphenylamino group.

[0020] The substituents that the alkyl group, alkoxy group, aryl group, heterocyclic group, silyl group, and amino group may further have are not particularly limited, and examples thereof include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, tert-pentyl group, neopentyl group, n-hexyl group, and cyclohexyl group; methoxy group, ethoxy group, isopropoxy group, n-butoxy group, and tert-butoxy group; Alkoxy group, 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 substituted amino groups such as an Nylamino group, an N,N-dimesitylamino group, an N-phenyl-N-(4-tert-butylphenyl)amino group, or an N-phenyl-N-(4-trifluoromethylphenyl)amino group; aryl groups such as 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, or a tert-phenyl group; thienyl group; and pyrrolyl groups. , a pyrazinyl group, a pyridyl group, an indolyl group, a quinolyl group, an isoquinolyl group, a naphthyridinyl group, an acridinyl group, a phenanthrolinyl group, etc., a heteroaryl group such as 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, or an oxadiazolyl group, a cyano group, a trifluoromethyl group, or the like.

[0021] The condensed polycyclic hydrocarbon skeleton refers to a compound having a structure in which two or more ring structures are condensed and composed of hydrocarbons. Specific examples thereof include a naphthalene skeleton, a phenanthroline skeleton, an anthracene skeleton, a fluorene skeleton, an acenaphthylene skeleton, a chrysene skeleton, a pyrene skeleton, a triphenylene skeleton, a fluoranthene skeleton, a perylene skeleton, a biphenylene skeleton, and a tetracene skeleton. The condensed polycyclic hydrocarbon skeleton may further have an alkyl group, an aralkyl group, an aryl group, or the like as a substituent. Specific examples thereof include a methyl group, an ethyl group, an isobutyl group, a tert-butyl group, a phenyl group, a biphenyl group, a naphthyl group, a ter-phenyl group, a benzyl group, and a phenylethyl group.

[0022] The heterocyclic skeleton refers to a structure having a ring structure containing a heteroatom. Specific examples thereof include a thiophene skeleton, a pyrroline skeleton, a pyrazine skeleton, a pyridine skeleton, an indoline skeleton, a quinoline skeleton, an isoquinoline skeleton, a naphthyridine skeleton, an acridine skeleton, a phenanthroline skeleton, a carbazole skeleton, a benzo[a]carbazole skeleton, a benzo[b]carbazole skeleton, a benzo[c]carbazole skeleton, a phenazine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a benzothiophene skeleton, a dibenzothiophene skeleton, a benzofuran skeleton, a dibenzofuran skeleton, an oxazoline skeleton, and an oxadiazine skeleton.

[0023] HOMO(A), HOMO(B), HOMO(C), HOMO(D), HOMO(E), HOMO(F), HOMO(G), HOMO(H), HOMO(I), and HOMO(J) represent the HOMO energy level of the first compound, the HOMO energy level of the second compound, the HOMO energy level of the third compound, the HOMO energy level of the fourth compound, the HOMO energy level of the fifth compound, the HOMO energy level of the sixth compound, the HOMO energy level of the seventh compound, the HOMO energy level of the eighth compound, the HOMO energy level of the ninth compound, and the HOMO energy level of the tenth compound, respectively.

[0024] LUMO(A), LUMO(B), LUMO(C), LUMO(D), LUMO(E), LUMO(F), LUMO(G), LUMO(H), LUMO(J), and LUMO(K) represent the LUMO energy level of the first compound, the LUMO energy level of the second compound, the LUMO energy level of the third compound, the LUMO energy level of the fourth compound, the LUMO energy level of the fifth compound, the LUMO energy level of the sixth compound, the LUMO energy level of the seventh compound, the LUMO energy level of the eighth compound, the LUMO energy level of the tenth compound, and the LUMO energy level of the eleventh compound, respectively.

[0025] The HOMO is the highest occupied molecular orbital, and the LUMO is the lowest unoccupied molecular orbital.

[0026] In this specification, the host material is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. The guest (dopant) material is a compound with a mass ratio smaller than that of the host compound among the compounds constituting the light-emitting layer, and is a compound that is mainly responsible for emitting light. The assist material is a compound with a mass ratio smaller than that of the host compound among the compounds constituting the light-emitting layer, and assists the emission of the guest compound. The assist compound is also called a second host compound.

[0027] <Organic light-emitting element> The organic light-emitting device according to this embodiment will be described below with reference to FIG.

[0028] The organic light-emitting device according to this embodiment is an organic light-emitting device having, in this order, a first electrode 200, a first light-emitting unit 300, a charge generation layer 400, a second light-emitting unit 500, and a second electrode 600. These may be provided on a substrate 1. In the organic light-emitting device according to this embodiment, the first electrode 200 may be an anode, and the second electrode 600 may be a cathode.

[0029] The organic light-emitting element according to this embodiment is a so-called tandem-type light-emitting element (stacked organic light-emitting element) that has a charge generation layer and a first light-emitting unit and a second light-emitting unit sandwiching the charge generation layer.

[0030] The organic light-emitting device according to this embodiment includes a second light-emitting layer 304 as the first light-emitting unit 300. The first light-emitting unit 300 may include a third organic layer 303, a second light-emitting layer 304, and a fourth organic layer 305, arranged from the first electrode 200 side. The third organic layer 303 may be a first electron blocking layer, and the fourth organic layer 305 may be a first hole blocking layer. In addition to these, the first light-emitting unit 300 may further include a first hole injection layer 301, a first hole transport layer 302, a first electron transport layer 306, a first electron injection layer 307, and the like. The third organic layer 303 and the second light-emitting layer 304 may be in contact with each other. Furthermore, the second light-emitting layer and the fourth organic layer may be in contact with each other. In the organic light-emitting device according to this embodiment, the third organic layer 303 may include a seventh compound, the second light-emitting layer 304 may include a fifth compound and a sixth compound, and the fourth organic layer 305 may include an eighth compound. The fifth and sixth compounds may be either a host material, an assist material, or a guest material.

[0031] The organic light-emitting device according to this embodiment has a second light-emitting unit 500 including a first organic layer 502, a first light-emitting layer 503, and a second organic layer 504 arranged from the first electrode 200 side. For example, the first organic layer 502 may be a second electron blocking layer, and the second organic layer 504 may be a second hole blocking layer. The first organic layer 502 and the first light-emitting layer 503 may be in contact with each other. The first light-emitting layer 503 and the second organic layer 504 may be in contact with each other. In the organic light-emitting device according to this embodiment, the first organic layer 502 includes a first compound, the first light-emitting layer 503 includes a second compound and a third compound, and the second organic layer 504 includes a fourth compound. The second compound and the third compound may be a host material, an assist material, or a guest material.

[0032] Furthermore, in the organic light-emitting device according to this embodiment, the first light-emitting layer 503 may have a first light-emitting portion and a second light-emitting portion. In this case, the first light-emitting portion may have a second compound, and the second light-emitting portion may have a third compound. The first light-emitting portion and the second light-emitting portion may have a second compound and a third compound, respectively. Furthermore, the first organic layer 503 and the first light-emitting portion may be in contact with each other, and the second light-emitting portion and the second organic layer may be in contact with each other. Furthermore, the first light-emitting portion and the second light-emitting portion may be in contact with each other.

[0033] In the organic light-emitting device according to this embodiment, the first light-emitting layer 503 may contain a first light-emitting material, and the second light-emitting layer 304 may contain a third light-emitting material. When the first light-emitting layer 503 contains a first light-emitting portion and a second light-emitting portion, the first light-emitting portion may contain the first light-emitting material, the second light-emitting portion may contain the second light-emitting material, and the second light-emitting layer 304 may contain the third light-emitting material. The sixth compound may be the third light-emitting material.

[0034] The organic light-emitting device according to this embodiment may further include, as a second light-emitting unit 500, a second hole-transporting layer 501, a second electron-transporting layer 505, a second electron-injecting layer 506, and the like.

[0035] The organic light-emitting device according to this embodiment has a charge generation layer 400 between the first light-emitting unit 300 and the second light-emitting unit 500. Specific configurations of the charge generation layer 400 are shown below, but are not limited thereto. (i) n-type charge generation layer / hole injection layer (ii) n-type charge generation layer / p-type charge generation layer (iii) n-type charge generation layer / connection layer / hole injection layer (iv) n-type charge generation layer / connection layer / p-type charge generation layer In the organic light-emitting device according to this embodiment, the n-type charge generating layer may contain an organic compound with high electron donating properties, such as an alkali metal atom, an alkaline earth metal atom, or a compound having an imidazolidine skeleton, and preferably contains an alkali metal atom or an alkaline earth metal atom, more preferably contains a lithium atom or a cesium atom. The n-type charge generating layer may also be a mixed layer containing a first organic compound and a second organic compound.

[0036] The first organic compound is, for example, a nitrogen-containing aromatic compound. Specific examples include phenanthrolinyl, oxazolyl, oxadiazolyl, diazolyl, thiadiazolyl, triazolyl, naphthyridinyl, and derivatives thereof. Among these, the first organic compound is preferably a phenanthroline derivative or a naphthyridine derivative. Phenanthroline derivatives and naphthyridine derivatives have particularly strong interactions with alkali metals, making them particularly suitable as materials for the n-type charge generating layer.

[0037] The second organic compound is a condensed polycyclic hydrocarbon compound or an organic compound represented by any of the general formulae (1-1) to (1-10).

[0038] [ka]

[0039] In the general formulae (A-1) to (A-10), R to R 909 are each independently selected from the group consisting of a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group.

[0040] The p-type charge generating layer may be a mixed layer containing a hole transporting compound and an electron withdrawing compound.

[0041] The hole injection layer may be a layer comprising an electron-withdrawing compound or a metal oxide.

[0042] The connecting layer may be a layer containing an electron transport compound or a hole transport compound. An n-type organic semiconductor layer containing a compound with a LUMO of −5.0 eV or less may be provided between the n-type charge generating layer and the p-type charge generating layer. The connecting layer may also be a layer made of a condensed polycyclic hydrocarbon compound, and more preferably a layer made of only a condensed polycyclic hydrocarbon compound. The connecting layer may have both a layer containing an electron transport compound or a hole transport compound and a layer made of a condensed polycyclic hydrocarbon compound.

[0043] The charge generation layer 400 serves to inject electrons into the first light-emitting unit 300. Therefore, in the organic light-emitting device according to this embodiment, the first light-emitting unit 300 does not need to have the first electron injection layer 307. When the first light-emitting unit 300 does not have the first electron injection layer 307, the driving voltage of the organic light-emitting device can be reduced.

[0044] Furthermore, in the organic light-emitting device according to this embodiment, the first light-emitting unit 300 may include a first electron injection layer 307. In this case, the first electron injection layer 307 and the charge generation layer 400 preferably include a common material, and the first electron injection layer 307 and the n-type charge generation layer preferably include a common material. When the first electron injection layer 307 and the charge generation layer 400 include a common material, the adhesion between the first electron injection layer 307 and the charge generation layer 400 is increased, thereby further improving the function as an electron injection layer.

[0045] The charge generation layer 400 serves to inject holes into the second light-emitting unit 500. Therefore, in the organic light-emitting device according to this embodiment, the second light-emitting unit 500 does not need to have a second hole injection layer. When the second light-emitting unit 500 does not have a second hole injection layer, the driving voltage of the organic light-emitting device can be reduced.

[0046] Furthermore, in the organic light-emitting device according to this embodiment, the second light-emitting unit 500 may have a second hole injection layer. In this case, the second hole injection layer and the charge generation layer 400 preferably have a common material, and the second hole injection layer and the p-type charge generation layer or the hole injection layer of the charge generation layer 400 preferably have a common material. When the second hole injection layer and the charge generation layer 400 have a common material, the adhesion between the second hole injection layer and the charge generation layer 400 is increased, thereby further improving the function as a hole injection layer.

[0047] The organic light-emitting device according to this embodiment may have a third light-emitting unit in addition to the first light-emitting unit 300 and the second light-emitting unit 500. The third light-emitting unit may be provided between the first electrode 200 and the first light-emitting unit 300, between the first light-emitting unit 300 and the second light-emitting unit 500, or between the second light-emitting unit 500 and the second electrode 600.

[0048] Furthermore, the organic light-emitting device according to this embodiment may have an element configuration capable of emitting white light. Specifically, the first light-emitting unit 300 may emit blue light, and the second light-emitting unit 500 may emit red and green light. Alternatively, the first light-emitting unit 300 may emit red and green light, and the second light-emitting unit 500 may emit blue light. The first light-emitting unit 300, the second light-emitting unit 500, and the third light-emitting unit may emit red, green, and blue light, respectively.

[0049] Furthermore, the organic light-emitting device according to this embodiment may have a device configuration capable of emitting light other than white. Specifically, the first light-emitting unit 300 and the second light-emitting unit 500 may emit light of the same color. By using such a device configuration, an organic light-emitting device with improved brightness can be produced.

[0050] The organic light-emitting device according to this embodiment has the following features. (1) The first compound, the second compound, the third compound, and the fourth compound satisfy the relationship (a). (a) HOMO(B)-HOMO(A)≧0 eV This feature will be described in detail below.

[0051] The organic light-emitting device according to this embodiment is an organic light-emitting device having a charge generation layer 400 between a first light-emitting unit 300 and a second light-emitting unit 500. In such an organic light-emitting device, holes generated in the charge generation layer 400 are easily injected into the second light-emitting unit 500, particularly the first light-emitting layer 503, and thus the device exhibits a low driving voltage.

[0052] Specifically, when the first compound, the second compound, the third compound, and the fourth compound satisfy the following relationship (a), the organic light-emitting device according to this embodiment exhibits a low driving voltage. (a) HOMO(B)-HOMO(A)≧0 eV Moreover, the organic light-emitting device according to this embodiment preferably satisfies the relationship (a1). (a1) HOMO(B)-HOMO(A)>LUMO(D)-LUMO(C) The relationship (a) indicates that the HOMO energy level of first light-emitting layer 503 is equal to or higher than the HOMO energy level of first organic layer 502. The relationship (a1) indicates that the difference between the HOMO energy level of first organic layer 502 and the HOMO energy level of first light-emitting layer 503 is larger than the difference between the LUMO energy level of second organic layer 504 and the LUMO energy level of first light-emitting layer 503.

[0053] Here, the HOMO energy level of the first organic layer 502 is the HOMO energy level of the first compound. The LUMO energy level of the second organic layer 504 is the LUMO energy level of the fourth compound. The HOMO energy level of the first light-emitting layer 503 may be the HOMO energy level of the compound with the highest HOMO energy level (closest to vacuum level) among the compounds contained in the first light-emitting layer 503, the HOMO energy level of the compound with the highest content in the first light-emitting layer 503, or the HOMO energy level of the compound with the highest HOMO energy level among the compounds contained in the first light-emitting layer 503 that are present in an amount of 10 parts by mass or more when the first light-emitting layer 503 is taken as 100 parts by mass. For example, the HOMO energy level of the first light-emitting layer 503 may be the HOMO energy level of the second compound, specifically the HOMO energy level of the host material, the HOMO energy level of the assist material, or the HOMO energy level of the guest material. Furthermore, the LUMO energy level of the first light-emitting layer 503 may be the LUMO energy level of the compound with the lowest LUMO energy level (farthest from the vacuum level) among the compounds contained in the first light-emitting layer 503, the LUMO energy level of the compound with the highest content in the first light-emitting layer 503, the LUMO energy level of the compound with the lowest LUMO energy level among the compounds contained in the first light-emitting layer 503 and with a content of 10 parts by mass or more when the first light-emitting layer 503 is taken as 100 parts by mass. For example, the LUMO energy level of the first light-emitting layer 503 may be the LUMO energy level of the third compound, specifically, the LUMO energy level of the host material, the LUMO energy level of the assist material, and the LUMO energy level of the guest material. The same applies to the HOMO energy levels and LUMO energy levels of the first and second light-emitting portions.

[0054] Table 1 shows the configurations and voltage ratios of the first organic layer 502, the first light-emitting layer 503, and the second organic layer 504 of the second light-emitting unit 500. The voltage ratios are relative values ​​when the driving voltage of Comparative Example 1 is set to 1.0. The ΔHOMO and ΔLUMO in Table 1 are as follows: ΔHOMO = HOMO(B) - HOMO(A) ΔLOMO = LUMO(D) - LUMO(C) The HOMO and LUMO can be calculated using molecular orbital calculations, such as density functional theory (DFT), using B3LYP as the functional and 6-31G* as the basis function.Gaussian09(Gaussian09,RevisionC.01,MJFrisch,GWTrucks,HBSchlegel,GEScuseria,MARobb, JRCheeseman,G.Scalmani,V.Barone,B.Mennucci,GAPetersson,H.Nakatsuji,M.Caricato,X.Li,HPHratchian,AF Izmailov,J.Bloino,G.Zheng,JLSonnenberg,M.Hada,M.Ehara,K.Toyota,R.Fukuda,J.Hasegawa,M.Ishida,T.Nak ajima,Y.Honda,O.Kitao,H.Nakai,T.Vreven,JAMontgomery,Jr.,JEPeralta,F.Ogliaro,M.Bearpark,JJHeyd,E.B rothers,KNKudin,VNStaroverov,T.Keith,R.Kobayashi,J.Normand,K.Raghavachari,A.Rendell,JCBurant,SSIy engar,J.Tomasi,M.Cossi,N.Rega,JMMillam,M.Klene,JEKnox,JBCross,V.Bakken,J.Adamo,J.Jaramillo,R.Gomp erts,REStratmann,O.Yazyev,AJAustin,R.Cammi,J.Pomelli,JWOchterski,RLMartin,K.Morokuma,VGZakrzewski,GAVoth,P.Salvador,JJDannenberg,S.Dapprich,ADDaniels,O.Farkas,JBForesman,JVOrtizski,J.Condizski DJFox,Gaussian,Inc.,Wallingford CT,2010.)

[0055] The HOMO and LUMO can also be calculated using the ionization potential and band gap. The HOMO can be estimated by measuring the ionization potential. The ionization potential can be measured by depositing the compound to be measured on a substrate such as glass to create a deposited film. This deposited film can be measured using a measuring device such as an AC-3. The band gap can be measured by dissolving the compound to be measured in a solvent such as toluene and irradiating it with excitation light. The band gap can be measured by measuring the absorption edge of the absorption spectrum where the solution absorbs the excitation light. Alternatively, the compound to be measured can be deposited on a substrate such as glass and irradiating the deposited film with excitation light. The band gap can be measured by measuring the absorption edge of the absorption spectrum where the deposited film absorbs the excitation light.

[0056] The LUMO can be calculated using the band gap and ionization potential values. Adding the band gap value to the ionization potential gives the LUMO.

[0057] The LUMO can also be estimated from the reduction potential. For example, the one-electron reduction potential can be estimated using CV (cyclic volmetry) measurements. CV measurements are performed, for example, in a 0.1 M tetrabutylammonium perchlorate solution in DMF, with an Ag / Ag reference electrode. + The LUMO can be estimated by subtracting the difference between the reduction potential of the compound obtained and that of ferrocene from the ionization potential of ferrocene, which is -4.8 eV.

[0058] In the present invention, the ionization potential and band gap of the above-mentioned vapor-deposited film are measured, the HOMO is estimated from the obtained ionization potential, and the LUMO is calculated by adding the band gap to the ionization potential.

[0059] [Table 1]

[0060] As can be seen from Table 1, the organic light-emitting devices of Inventions A to C have a ΔHOMO of 0 eV or more. Therefore, holes generated in the charge generation layer 400 are easily injected into the first light-emitting layer 503. As a result, the organic light-emitting devices of Inventions A to C exhibit a lower voltage ratio. On the other hand, the organic light-emitting device of Comparative Example A has a ΔHOMO of less than 0 eV. Therefore, holes generated in the charge generation layer 400 are difficult to inject into the first light-emitting layer 503. As a result, the organic light-emitting device of Comparative Example A exhibits a high voltage ratio.

[0061] Furthermore, holes generated in the charge generation layer 400 are easily injected into the first light-emitting layer 503, which makes it difficult for holes to remain in the charge generation layer 400. Since holes are less likely to remain in the charge generation layer 400, it can be expected that deterioration of the charge generation layer due to holes will be reduced. Therefore, the organic light-emitting element according to this embodiment can be expected to have excellent durability.

[0062] Furthermore, the organic light-emitting device according to Invention A has a configuration in which ΔHOMO is larger than ΔLUMO. Therefore, holes generated in the charge generation layer 400 are more easily injected into the first light-emitting layer 503. As a result, the organic light-emitting device according to Invention A exhibits a lower driving voltage.

[0063] As described above, when the first compound, the second compound, the third compound, and the fourth compound satisfy the following relationship (a), the organic light-emitting device according to this embodiment exhibits a low driving voltage. (a) HOMO(B)-HOMO(A)≧0 eV The organic light-emitting device according to this embodiment more preferably satisfies the relationship of formula (a2) or (a3). (a2) HOMO(B)-HOMO(A)≧0eV>LUMO(D)-LUMO(C) (a3) HOMO(B)-HOMO(A)>LUMO(D)-LUMO(C)>0eV The organic light-emitting element according to this embodiment is preferable because it satisfies formula (a2) or formula (a3), since holes are more easily injected than electrons into second light-emitting layer 304. Furthermore, an organic light-emitting element that satisfies formula (a3) ​​is configured such that electrons are also more easily injected into second light-emitting layer 304, making it easier to keep the recombination region of electrons and holes within second light-emitting layer 304, and is also expected to have improved luminous efficiency.

[0064] In the specific examples shown in Table 1, the second compound is an assist material and the third compound is a host material, but this does not limit the second compound and the third compound.

[0065] The organic light-emitting device according to this embodiment more preferably has the following configuration. (2) The fifth, seventh, and eighth compounds satisfy the relationship (b). (b) LUMO(H)-LUMO(E)≧0eV>HOMO(E)-HOMO(G) (3) The fifth and sixth compounds satisfy the relationship (c). (c) HOMO(F)>HOMO(E) (4) The fifth, seventh, and eighth compounds satisfy the relationship (d). (d) HOMO(E)-HOMO(G)≧0 eV (5) The fifth and sixth compounds satisfy the relationship (e). (e) LUMO(E)>LUMO(F) (6) The freely rotatable bond of the third compound is a carbon-carbon bond. (7) The third compound is a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent. (8) The first light-emitting layer 503 is a phosphorescent light-emitting layer, and the second light-emitting layer 304 is a fluorescent light-emitting layer.

[0066] These will be explained below.

[0067] (2) The fifth, seventh, and eighth compounds satisfy the relationship (b). (b) LUMO(H)-LUMO(E)≧0 eV Moreover, it is preferable that the organic light-emitting device according to this embodiment further satisfies the relationship (b1). (b1) LUMO(H)-LUMO(E)>HOMO(E)-HOMO(G) In the organic light-emitting device according to this embodiment, the relationship (b) indicates that the LUMO energy level of fourth organic layer 305 is equal to or higher than the LUMO energy level of second light-emitting layer 304. Furthermore, the relationship (b1) indicates that the difference between the LUMO energy level of fourth organic layer 305 and the LUMO energy level of second light-emitting layer 304 is larger than the difference between the HOMO energy level of third organic layer 303 and the HOMO energy level of second light-emitting layer 304.

[0068] Here, the HOMO energy level of the third organic layer 303 is the HOMO energy level of the seventh compound, and the LUMO energy level of the fourth organic layer 305 is the LUMO energy level of the eighth compound.

[0069] The LUMO energy level of second light-emitting layer 304 may be the LUMO energy level of the compound with the lowest LUMO energy level among the compounds contained in second light-emitting layer 304, the LUMO energy level of the compound with the highest content in second light-emitting layer 304, the LUMO energy level of the compound with the lowest LUMO energy level among the compounds other than the compound with the lowest content in second light-emitting layer 304, or the LUMO energy level of the compound with the lowest LUMO energy level among the compounds contained in second light-emitting layer 304 and with a content of 10 parts by mass or more per 100 parts by mass of second light-emitting layer 304. For example, the LUMO energy level of second light-emitting layer 303 may be the LUMO energy level of the sixth compound, specifically the LUMO energy level of the host material, the LUMO energy level of the assist material, and the LUMO energy level of the guest material.

[0070] The HOMO energy level of second light-emitting layer 304 may be the HOMO energy level of the compound with the highest HOMO energy level among the compounds contained in second light-emitting layer 304, the HOMO energy level of the compound with the highest content in second light-emitting layer 304, the HOMO energy level of a compound with the highest HOMO energy level among compounds other than the compound with the lowest content in second light-emitting layer 304, or the HOMO energy level of a compound with the highest HOMO energy level among compounds contained in second light-emitting layer 304 that are present in an amount of 10 parts by mass or more per 100 parts by mass of second light-emitting layer 304. For example, the HOMO energy level of second light-emitting layer 304 may be the HOMO energy level of the sixth compound, specifically the HOMO energy level of the host material, the HOMO energy level of the assist material, or the HOMO energy level of the guest material.

[0071] The organic light-emitting device according to this embodiment satisfies the relationship (b), so that electrons generated in the charge generation layer 400 are easily injected into the second light-emitting layer 304. Therefore, the organic light-emitting device according to this embodiment exhibits a lower driving voltage.

[0072] Furthermore, electrons generated in the charge generation layer 400 are easily injected into the second light-emitting layer 304, which makes it difficult for electrons to remain in the charge generation layer 400. Since electrons are less likely to remain in the charge generation layer 400, it is expected that deterioration of the charge generation layer due to electrons can be reduced. Therefore, the organic light-emitting device according to this embodiment has excellent durability.

[0073] The organic light-emitting device according to this embodiment more preferably satisfies the relationship of formula (b1) or (b2). (b1) LUMO(H)-LUMO(E)≧0eV>HOMO(E)-HOMO(G) (b2) LUMO(H)-LUMO(E)>HOMO(E)-HOMO(G)≧0eV The organic light-emitting element according to this embodiment is preferable because it satisfies formula (b1) or formula (b2), since electrons are more easily injected than holes into second light-emitting layer 304. Furthermore, an organic light-emitting element that satisfies formula (b2) is configured such that holes are also more easily injected into second light-emitting layer 304, making it easier to keep the recombination region of electrons and holes within second light-emitting layer 304, and is also expected to have improved luminous efficiency.

[0074] In the organic light-emitting device according to this embodiment, the fifth compound may be a host material and the sixth compound may be an assist material or a guest material, or the fifth compound may be an assist material and the sixth compound may be a guest material.

[0075] (3) The fifth and sixth compounds satisfy the relationship (c). (c) HOMO(F)>HOMO(E) In the organic light-emitting device according to this embodiment, the relationship (c) indicates that the second light-emitting layer 304 has a structure that easily traps holes. This structure can reduce the number of holes supplied from the first electrode that leak from the second light-emitting layer 304 and reach the charge generation layer 400. It is more preferable that the organic light-emitting device according to this embodiment satisfies the relationship (c1) or (c2). (c1) HOMO(F)-HOMO(E)≧0.15 eV (c2) HOMO(F)-HOMO(E)≧0.20 eV Furthermore, in the organic light-emitting device according to this embodiment, the content of the sixth compound is less than the content of the fifth compound, and the fifth compound may be a host material and the sixth compound may be an assist material or a guest material, or the fifth compound may be an assist material and the sixth compound may be a guest material.

[0076] The organic light-emitting device according to this embodiment can reduce holes leaking from the second light-emitting layer 304, and therefore can confine the recombination region of holes and electrons to the second light-emitting layer 304. As a result, the organic light-emitting device according to this embodiment has excellent luminous efficiency.

[0077] Furthermore, holes are less likely to reach the charge generation layer 400, which reduces deterioration of the charge generation layer 400 due to holes. As a result, the organic light emitting device according to this embodiment has superior durability.

[0078] (4) The fifth, seventh, and eighth compounds satisfy the relationship (d). (d) HOMO(E)-HOMO(G)≧0 eV Moreover, it is preferable that the organic light-emitting device according to this embodiment further satisfies the relationship (d1). (d1) HOMO(E)-HOMO(G)>LUMO(H)-LUMO(E) In the organic light-emitting device according to this embodiment, the relationship (d) indicates that the HOMO energy level of second light-emitting layer 304 is equal to or higher than the HOMO energy level of third organic layer 303. Furthermore, the relationship (d1) indicates that the difference between the HOMO energy level of third organic layer 303 and the HOMO energy level of second light-emitting layer 304 is larger than the difference between the LUMO energy level of fourth organic layer 305 and the LUMO energy level of second light-emitting layer 304.

[0079] Here, the HOMO energy level of the third organic layer 303 is the HOMO energy level of the seventh compound, and the LUMO energy level of the fourth organic layer 305 is the LUMO energy level of the eighth compound.

[0080] The LUMO energy level of second light-emitting layer 304 may be the LUMO energy level of the compound with the lowest LUMO energy level among the compounds contained in second light-emitting layer 304, the LUMO energy level of the compound with the highest content in second light-emitting layer 304, the LUMO energy level of the compound with the lowest LUMO energy level among the compounds other than the compound with the lowest content in second light-emitting layer 304, or the LUMO energy level of the compound with the lowest LUMO energy level among the compounds contained in second light-emitting layer 304 and with a content of 10 parts by mass or more per 100 parts by mass of second light-emitting layer 304. For example, the LUMO energy level of second light-emitting layer 303 may be the LUMO energy level of the host material, the assist material, or the guest material.

[0081] The HOMO energy level of the second light-emitting layer 304 may be the HOMO energy level of the compound with the highest HOMO energy level among the compounds contained in the second light-emitting layer 304, the HOMO energy level of the compound with the highest content in the second light-emitting layer 304, the HOMO energy level of a compound with the highest HOMO energy level among compounds other than the compound with the lowest content in the second light-emitting layer 304, or the HOMO energy level of a compound with the highest HOMO energy level among compounds contained in the second light-emitting layer 304 that are present in an amount of 10 parts by mass or more per 100 parts by mass of the second light-emitting layer 304. For example, the HOMO energy level of the second light-emitting layer 304 may be the HOMO energy level of the host material, the HOMO energy level of the assist material, or the HOMO energy level of the guest material.

[0082] The organic light-emitting device according to this embodiment satisfies the relationship (d), so that holes supplied from the first electrode 200 are easily injected into the second light-emitting layer 304. Therefore, the organic light-emitting device according to this embodiment exhibits a lower driving voltage.

[0083] The organic light-emitting device according to this embodiment more preferably satisfies the relationship of formula (d2) or (d3). (d2) HOMO(E)-HOMO(G)≧0eV>LUMO(H)-LUMO(E) (d3) HOMO(E)-HOMO(G)>LUMO(H)-LUMO(E)>0eV The organic light-emitting element according to this embodiment is preferable because it satisfies formula (d2) or formula (d3), since holes are more easily injected than electrons into second light-emitting layer 304. Furthermore, an organic light-emitting element that satisfies formula (d3) is configured such that electrons are also more easily injected into second light-emitting layer 304, making it easier to keep the recombination region of electrons and holes within second light-emitting layer 304, and is also expected to have improved luminous efficiency.

[0084] In the organic light-emitting device according to this embodiment, the fifth compound may be a host material and the sixth compound may be an assist material or a guest material, or the fifth compound may be an assist material and the sixth compound may be a guest material.

[0085] (5) The fifth and sixth compounds satisfy the relationship (e). (e) LUMO(E)>LUMO(F) In the organic light-emitting device according to this embodiment, the relationship (h) indicates that the second light-emitting layer 304 has a structure that easily traps electrons. This structure reduces the likelihood that electrons supplied from the charge generating layer 400 will leak from the second light-emitting layer 304 and reach the organic layer disposed on the first electrode 200 side. It is more preferable that the organic light-emitting device according to this embodiment satisfies the relationship (e1) or (e2). (e1) LUMO(E)-LUMO(F)≧0.15 eV (e2) LUMO(E)-LUMO(F)≧0.20 eV In addition, in the organic light-emitting device according to this embodiment, the content of the sixth compound is less than the content of the fifth compound, and the fifth compound may be a host material and the sixth compound may be an assist material or a guest material, or the fifth compound may be an assist material and the sixth compound may be a guest material.

[0086] The organic light-emitting device according to this embodiment can reduce electrons leaking from the second light-emitting layer 304, and therefore can confine the recombination region of holes and electrons to the second light-emitting layer 304. As a result, the organic light-emitting device according to this embodiment exhibits a lower driving voltage.

[0087] Furthermore, it is possible to reduce deterioration of the organic layer due to electrons, since electrons are less likely to reach the organic layer disposed on the first electrode 200 side. As a result, the organic light-emitting element according to this embodiment has superior durability.

[0088] (6) The freely rotatable bond of the third compound is a carbon-carbon bond. In the organic light-emitting device according to this embodiment, the freely rotatable single bond of the third compound is preferably a carbon-carbon bond, more preferably an sp2 carbon-sp2 carbon bond, more preferably all of the freely rotatable single bonds are carbon-carbon bonds, and more preferably all of the freely rotatable single bonds are sp2 carbon-sp2 carbon bonds.

[0089] The organic light-emitting device according to this embodiment has a configuration in which holes are injected into the first light-emitting layer 503 via the third compound. The third compound also plays a role in generating excitons in the organic light-emitting device. Therefore, the third compound preferably has a skeleton that is resistant to decomposition in the presence of holes or in a high-energy excited state. In this specification, a freely rotatable single bond refers to a bond in which unit A and unit B are not fused together, when the single bond between unit A and unit B is represented by "AB." Units A and B may be atoms such as carbon atoms or nitrogen atoms, or molecules such as benzene or carbazole. Table 2 shows the bond energies of each bond.

[0090] [Table 2]

[0091] The bond energy of F1 and F2, which have carbon-nitrogen bonds, is 3.9 eV. On the other hand, the bond energy of F3, which has a freely rotatable carbon-carbon bond, is 4.5 eV, and the bond energy of F4, which has a freely rotatable sp2 carbon bond, is 5.0 eV. Therefore, when the freely rotatable single bond is a carbon-carbon bond, it is preferable because it is a skeleton that is difficult to decompose. Among carbon-carbon bonds, bonds between sp2 carbons have particularly high bond energy, so a skeleton in which the freely rotatable single bond is an sp2 carbon-sp2 carbon bond is even more preferable because it is more difficult to decompose.

[0092] Similarly to the third compound, the freely rotatable bond of the fourth compound may be a carbon-carbon bond.

[0093] (7) The third compound is a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent. In the organic light-emitting device according to this embodiment, the third compound is preferably a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent.

[0094] The condensed polycyclic hydrocarbon skeleton may be a skeleton having 10 to 25 carbon atoms, and specific examples thereof include a naphthalene skeleton, a fluorene skeleton, an anthracene skeleton, a phenanthrene skeleton, a pyrene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a fluoranthene skeleton, and a perylene skeleton.

[0095] The heterocyclic skeleton may be a skeleton having 3 to 30 carbon atoms, or may be a skeleton having 3 to 18 carbon atoms, and examples thereof include a dibenzofuran skeleton, a dibenzothiophene skeleton, a xanthone skeleton, a thioxanthone skeleton, a carbazole skeleton, an indolocarbazole skeleton, and a triazine skeleton.

[0096] The third compound is preferably a compound having a triphenylene skeleton, a xanthone skeleton, or an indolocarbazole skeleton. In other words, the first compound is preferably a triphenylene derivative, a xanthone derivative, or an indolocarbazole derivative. These have highly planar skeletons, which enhance charge mobility. This makes it easier to inject charges into the light-emitting layer, resulting in a lower driving voltage.

[0097] Specific examples of the third compound include compounds represented by the following general formulas (1) to (3) and exemplary compounds EM1 to EM43 described below, but are not limited to these. (7-1) Compound represented by general formula (1)

[0098] [ka]

[0099] In general formula (1), Ar1 and Ar2 are each independently selected from a substituted or unsubstituted aryl group consisting of three or more rings, or a substituted or unsubstituted heterocyclic group consisting of three or more rings. The substituent represented by R is selected from a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, or a cyano group. When there are multiple Rs, the multiple Rs may be the same or different. n is an integer of 2 to 5, and m1 to m3 are each an integer of 0 to 4.

[0100] The compound of general formula (1) may also have at least one of the following characteristics: (7-1-1) In the general formula (1), Ar1 and Ar2 do not have an SP3 carbon. (7-1-2) In the general formula (1), the substituent represented by R is bonded to the m-position of the benzene that constitutes the phenylene chain. (7-1-3) In the general formula (1), m1 to m3 are 0. (7-1-4) In the general formula (1), n ​​is 3 or 4. (7-1-5) In the general formula (1), Ar1 and Ar2 are different skeletons. (7-1-6) In the general formula (1), when Ar1 and Ar2 are dibenzothiophene skeletons or dibenzofuran skeletons, the organic compound has at least one substituent. (7-1-7) One of Ar1 and Ar2 is a substituted or unsubstituted aryl group consisting of three or more rings, and the other is a substituted or unsubstituted heterocyclic group consisting of three or more rings. (7-2) Compounds having a skeleton of general formula (2) or (3)

[0101] [ka]

[0102] In general formulas (2) and (3), the cyclic units A to C are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. Q1 to Q3 are each independently selected from a direct bond, C(R A )(R B ), N(R C ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. A ~R C are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. C forms a ring with the adjacent cyclic units A to C.

[0103] Specific examples of the skeletons represented by general formulas (2) and (3) are as follows:

[0104] [ka]

[0105] Specific examples of the general formulae (1) to (3) are shown below, but the invention is not limited to these.

[0106] [ka]

[0107] [ka]

[0108] [ka]

[0109] [ka]

[0110] [ka]

[0111] [ka]

[0112] [ka]

[0113] [ka]

[0114] [ka]

[0115] [ka]

[0116] [ka]

[0117] [ka]

[0118] [ka]

[0119] (8) The first light-emitting layer 503 is a phosphorescent light-emitting layer, and the second light-emitting layer 304 is a fluorescent light-emitting layer. In the organic light-emitting device according to this embodiment, when the first light-emitting layer 503 contains a first light-emitting material and the second light-emitting layer 304 contains a third light-emitting material, the first light-emitting material is a phosphorescent material and the third light-emitting material is a fluorescent material.

[0120] Furthermore, when the first light-emitting section has a first light-emitting material, the second light-emitting section has a second light-emitting material, and the second light-emitting layer 304 has a third light-emitting material, the first light-emitting material and the second light-emitting material are phosphorescent materials, and the third light-emitting material is a fluorescent material.

[0121] The phosphorescent material is not particularly limited as long as it is a compound that mainly emits phosphorescence, and examples thereof include a compound represented by general formula (4) and exemplary compounds BD9, GD10 to GD18, and RD3 to RD10 described below. M(L)m(L')n(L'')p (4) In general formula (4), M represents a metal atom. Specifically, it is an iridium atom and a platinum atom. L, L', and L'' each represent a different bidentate ligand. m is selected from an integer of 1 or more and 3 or less. n and p are selected from integers of 0 or more and 2 or less, provided that m+n+p=3. When m is 2 or more, L's may be the same or different. When n is 2 or more, L's may be the same or different. When p is 2 or more, L''s may be the same or different.

[0122] M(L)m is represented by the general formula (4-1).

[0123] [ka]

[0124] In the general formula (4-1), Z1 to Z4 are each independently selected from C(R 21 ), and a nitrogen atom. 21 ~R 28 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, or a cyano group, provided that R 21 ~R 28 At least one of Z1 to Z4 is selected from a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group. 21 ), then R 21 may be the same as or different from each other.

[0125] Also, adjacent R 21 ~R 28 may be bonded to each other to form a ring.

[0126] M(L')n is represented by the general formula (4-2).

[0127] [ka]

[0128] In formula (4-2), Z5 to Z8 are C(R 35 ), and a nitrogen atom. 31 ~R 35 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, or a cyano group. 35 ), then R 35 may be the same as or different from each other.

[0129] Also, adjacent R 31 ~R 35 may be bonded to each other to form a ring.

[0130] M(L″)p is represented by the general formula (4-3).

[0131] [ka]

[0132] In formula (4-3), R 39 ~R 41 are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, and a cyano group.

[0133] Specific examples of the partial structure M(L) of the organometallic complex, which is a luminescent compound, are shown below, but are not limited to these. In the specific examples shown below, coordinate bonds are indicated by straight lines, dotted lines, or arrows.

[0134] [ka]

[0135] [ka]

[0136] [ka]

[0137] In the general formulae [Ir-5] to [Ir-8], [Ir-15], and [Ir-16], X' is selected from an oxygen atom, a sulfur atom, a substituted or unsubstituted carbon atom, and a substituted or unsubstituted nitrogen atom. 21 ~R 28 is as described in the general formula (4-1).

[0138] In the general formulas [Ir-1] to [Ir-20], adjacent R 21 ~R 29 may be bonded to each other to form a ring.

[0139] Specific examples of phosphorescent materials are shown below, but the present invention is not limited to these.

[0140] Specific examples of the luminescent compound are shown below, but the present invention is not limited to these.

[0141] [ka]

[0142]

change

[0143]

change

[0144]

change

[0145]

change

[0146]

change

[0147]

change

[0148]

change

[0149]

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[0150]

change

[0151]

change

[0152]

change

[0153] [ka]

[0154] [ka]

[0155] [ka]

[0156] [ka]

[0157] The fluorescent material is not particularly limited as long as it is a compound that mainly emits fluorescence, and examples thereof include compounds represented by general formulas (5) to (10), compounds having a plurality of structures represented by general formula (5), compounds having a plurality of structures represented by general formula (7), and exemplary compounds BD1 to BD8, BD10 and BD11, GD1 to GD9, and RD1 and RD2 described later.

[0158] [ka]

[0159] In the general formulas (5) and (6), the cyclic units A to C are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. Q1 to Q3 are each independently selected from a direct bond, C(R A )(R B ), N(R C ), B(R D ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. Q1 to Q3 are each independently selected from B(R D ) may be R A ~R Dare each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. A and R B may be bonded to each other to form a ring, and R A may bond with adjacent cyclic units A to C to form a ring, and R B The cyclic units A to C may be bonded to each other to form a ring. C may form a ring with the adjacent cyclic units A to C.

[0160] [ka]

[0161] In the general formulas (7) and (8), the cyclic units A to C are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. Q1 to Q3 are each independently selected from a direct bond, C(R A )(R B ), N(R C ), B(R D ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. Q1 to Q3 are each independently selected from N(R C ) may be R A ~R D are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. A and R B may be bonded to each other to form a ring, and R A may bond with adjacent cyclic units A to C to form a ring, and R B The cyclic units A to C may be bonded to each other to form a ring. C may form a ring with the adjacent cyclic units A to C.

[0162] In the compound consisting of multiple structures represented by general formula (5), multiple structures represented by general formula (5) may be fused via ring A, multiple structures represented by general formula (5) may be fused via ring B, or multiple structures represented by general formula (5) may be fused via ring C. The same applies to the compound consisting of multiple structures represented by general formula (5). Specific examples of the compound consisting of multiple structures represented by general formula (5) include, but are not limited to, the following compounds.

[0163] [ka]

[0164] Furthermore, in a compound consisting of multiple structures represented by general formula (7), multiple structures represented by general formula (5) may be fused via ring A, multiple structures represented by general formula (5) may be fused via ring B, or multiple structures represented by general formula (5) may be fused via ring C. The same applies to a compound consisting of multiple structures represented by general formula (8).

[0165] [ka]

[0166] In general formula (9), the cyclic units A to E are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. The cyclic units A to E may be a substituted or unsubstituted benzene skeleton. The cyclic units A, B, D, and E may be a substituted or unsubstituted benzene skeleton, and the cyclic unit C may be a substituted or unsubstituted benzene skeleton or naphthalene skeleton. Q1 to Q3 may be a direct bond, C(R A )(R B ), N(R C ), B(R D ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. Q1 to Q4 may be a direct bond. R A ~R Dare each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group.

[0167] Specific examples of the compound represented by general formula (9) include, but are not limited to, the following compounds:

[0168] [ka]

[0169] In general formula (10), R to R 20 are each independently selected from the group consisting of a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and a cyano group. 20 may be bonded to each other to form a ring. The bond may be via a chalcogen atom. R4 and R5, R9 and R 10 , R 14 and R 15 , R 19 and R 20 At least one of the combinations of R and R is bonded to each other. 10 , R 19 and R 20 At least one of the combinations of X1 and X2 is bonded to each other. X1 and X2 are each independently selected from the group consisting of a chalcogen atom, a substituted or unsubstituted imino group, a substituted or unsubstituted methylene group, and a substituted or unsubstituted silylene group.

[0170] Specific examples of general formula (10) are shown below, but are not limited to these.

[0171] [ka]

[0172] [ka]

[0173] [ka]

[0174] [ka]

[0175] [ka]

[0176] [ka]

[0177] The organic light-emitting device according to this embodiment may also have a configuration including, in this order, a first electrode, a first light-emitting unit, a first charge generation layer, a third light-emitting unit, a second charge generation layer, and a second light-emitting unit. In this embodiment, the first charge generation layer and the second charge generation layer may have the same configuration as the charge generation layer described above. In this embodiment, the first light-emitting unit and the second light-emitting unit may have the same configuration as the first light-emitting unit and the second light-emitting unit described above.

[0178] The third light-emitting unit has a fifth organic layer, a third light-emitting layer, and a sixth organic layer, in this order from the first electrode side. The fifth organic layer has a ninth compound, the third light-emitting layer has a tenth compound, and the sixth organic layer has an eleventh compound. The tenth compound may be a host material, an assist material, or a guest material. In this case, the ninth compound, the tenth compound, and the eleventh compound preferably satisfy the relationships (f) and (g). In this case, the second light-emitting layer of the first light-emitting unit preferably satisfies the relationship (b) or (c) described above. The relationship (b) is more preferably (b1). The relationship (c) is more preferably (c1), and even more preferably (c2). (f) HOMO(J)-HOMO(I)≧0 eV (g) LUMO(K)-LUMO(J)≧0 eV The relationship (f) indicates that the HOMO energy level of the third emitting layer is equal to or higher than the HOMO energy level of the fifth organic layer, and the relationship (g) indicates that the LUMO energy level of the sixth organic layer is equal to or higher than the LUMO energy level of the third emitting layer.

[0179] Here, the HOMO energy level of the fifth organic layer is the HOMO energy level of the ninth compound, and the LUMO energy level of the sixth organic layer is the LUMO energy level of the eleventh compound.

[0180] The HOMO energy level of the third emitting layer may be the HOMO energy level of the compound with the highest HOMO energy level (closest to the vacuum level) among the compounds contained in the third emitting layer, the HOMO energy level of the compound with the highest content in the third emitting layer, the HOMO energy level of the compound with the highest HOMO energy level among the compounds other than the compound with the lowest content in the third emitting layer, or the HOMO energy level of the compound with the highest HOMO energy level among the compounds contained in the third emitting layer and with a content of 10 parts by mass or more per 100 parts by mass of the third emitting layer. For example, the HOMO energy level of the third emitting layer may be the HOMO energy level of the tenth compound, specifically the HOMO energy level of the host material, the HOMO energy level of the assist material, or the HOMO energy level of the guest material.

[0181] The LUMO energy level of the third emitting layer may be the LUMO energy level of the compound with the lowest LUMO energy level (farthest from the vacuum level) among the compounds contained in the third emitting layer, the LUMO energy level of the compound with the highest content in the third emitting layer, the LUMO energy level of the compound with the lowest LUMO energy level among the compounds other than the compound with the lowest content in the third emitting layer, or the LUMO energy level of the compound with the lowest LUMO energy level among the compounds contained in the third emitting layer and with a content of 10 parts by mass or more when the third emitting layer is taken as 100 parts by mass. For example, the LUMO energy level of the third emitting layer may be the LUMO energy level of the tenth compound, specifically the LUMO energy level of the host material, the LUMO energy level of the assist material, and the LUMO energy level of the guest material.

[0182] In this embodiment, the third light-emitting unit satisfies the relationships (f) and (g), so that holes generated in the first charge-generating layer are easily injected into the third light-emitting layer, and electrons generated in the second charge-generating layer are easily injected into the fourth light-emitting layer. The organic light-emitting device according to this embodiment exhibits a lower driving voltage.

[0183] Furthermore, the organic light-emitting device according to this embodiment is configured such that electrons are less likely to remain in the first charge generation layer and holes are less likely to remain in the second charge generation layer. Since carriers (holes and / or electrons) are less likely to remain in the first charge generation layer and the second charge generation layer, it is expected that deterioration of the charge generation layer due to each carrier can be reduced. Therefore, the organic light-emitting device according to this embodiment also has excellent durability.

[0184] The organic light-emitting device according to this embodiment will be further described below.

[0185] <Other ingredients> In addition to the above, examples of the host compound and assist compound contained in the first light-emitting layer 503 and the second light-emitting layer 304 include, but are not limited to, aromatic hydrocarbon compounds or derivatives thereof, carbazole derivatives, azine derivatives, xanthone derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organic aluminum complexes such as tris(8-quinolinolato)aluminum, and organic beryllium complexes. Specific examples are shown below.

[0186] More preferably, aromatic hydrocarbon compounds such as pyrene derivatives (specific examples EM1 to EM4, EM10, EM12, EM26, and EM27), perylene derivatives (specific examples EM22 and EM23), anthracene derivatives (specific examples EM5 to EM8), and fluoranthene derivatives (EM25) are used, which can improve the durability of the light-emitting layer itself. Specific examples are shown below, but the present invention is not limited to these compounds.

[0187] [ka]

[0188] In addition to the above, guest materials mainly related to the light-emitting function include fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, anthracene derivatives, rubrene, etc.), quinacridone derivatives, coumarin derivatives, stilbene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, iridium complexes, platinum complexes, rhenium complexes, copper complexes, europium complexes, ruthenium complexes, and polymer derivatives such as poly(phenylenevinylene) derivatives, poly(fluorene) derivatives, and poly(phenylene) derivatives. Specific examples of compounds used as light-emitting materials are shown below, but are not limited to these.

[0189] [ka]

[0190] [ka]

[0191] As the hole injection transport material, a material with high hole mobility is preferred, which facilitates the injection of holes from the anode and transports 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 and transport properties include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. Furthermore, the above-mentioned hole injection and transport materials are also suitable for use in electron blocking layers or p-type charge generating layers. Specific examples of compounds usable as hole injection and transport materials are listed below, but the present invention is not limited to these.

[0192] [ka]

[0193] The electron transport material can be selected from materials capable of transporting electrons injected from the cathode to the light-emitting layer, 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, naphthyridine derivatives, organoaluminum complexes, and fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, chrysene derivatives, anthracene derivatives, etc.). Furthermore, the above-mentioned electron transport materials are also suitable for use in the hole-blocking layer. Specific examples of compounds usable as electron transport materials are listed below, but are not limited to these. Using a hydrocarbon compound in the hole-blocking layer adjacent to the light-emitting layer is preferred because it suppresses deterioration of the hole-blocking layer and improves the durability of the light-emitting device itself, but is not limited to hydrocarbon compounds. Specific examples are listed below.

[0194] [ka]

[0195] The electron injection material can be selected from those that allow easy electron injection from the cathode, taking into consideration the balance with hole injection properties, etc. Examples of organic compounds include n-type dopants and reducing dopants. Examples include compounds containing alkali metals such as lithium fluoride, lithium complexes such as lithium quinolinol, benzimidazolidine derivatives, imidazolidine derivatives, fulvalene derivatives, and acridine derivatives. They can also be used in combination with the above-mentioned electron transport materials.

[0196] [Configuration of organic light-emitting element] The organic light-emitting element is provided by forming an insulating layer, a first electrode, an organic compound layer, and a second electrode on a substrate. A protective layer, a color filter, a microlens, etc. may be provided on the cathode. When a color filter is provided, a planarizing layer may be provided between the protective layer. The planarizing layer may be made of acrylic resin or the like. The same applies when a planarizing layer is provided between the color filter and the microlens.

[0197] [substrate] Examples of the substrate include quartz, glass, a silicon wafer, a resin, and a metal. Furthermore, the substrate may be provided with a switching element such as a transistor and wiring, and an insulating layer thereon. Any material can be used for the insulating layer, as long as it allows for the formation of a contact hole so that wiring can be formed between the first electrode and the insulating layer, and ensures insulation from wiring that is not connected. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0198] [electrode] A pair of electrodes can be used. The pair of electrodes may be an anode and a cathode. When an electric field is applied in the direction in which the organic light-emitting element emits light, the electrode with a higher potential is the anode, and the other is the cathode. It can also be said that the electrode that supplies holes to the light-emitting layer is the anode, and the electrode that supplies electrons is the cathode.

[0199] The anode material should have as high a work function as possible. Examples include simple metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten, mixtures containing these metals, alloys of these metals, and metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide. Conductive polymers such as polyaniline, polypyrrole, and polythiophene can also be used.

[0200] These electrode materials may be used alone or in combination of two or more. The anode may be composed of one layer or multiple layers.

[0201] When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates thereof can be used. The above materials can also function as a reflective film without functioning as an electrode. When used as a transparent electrode, transparent conductive oxide layers such as indium tin oxide (ITO) and indium zinc oxide can be used, but are not limited to these. Photolithography techniques can be used to form the electrode.

[0202] On the other hand, materials with a low work function are preferred for the cathode. Examples include alkali metals such as lithium, alkaline earth metals such as calcium, and metals such as aluminum, titanium, manganese, silver, lead, and chromium, as well as mixtures containing these metals. Alternatively, alloys combining these metals can be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver can be used. Metal oxides such as indium tin oxide (ITO) can also be used. These electrode materials can be used alone or in combination. The cathode can have either a single-layer or multi-layer structure. Among these, silver is preferred, and a silver alloy is even more preferred to reduce silver aggregation. The alloy ratio is not critical as long as silver aggregation can be reduced. For example, the silver:other metal ratio can be 1:1, 3:1, or the like.

[0203] 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.

[0204] [Pixel isolation layer] The pixel separation layer is formed of a silicon nitride (SiN) film, a silicon oxynitride (SiON) film, or a silicon oxide (SiO) film formed using a chemical vapor deposition (CVD) method. To increase the in-plane resistance of the organic compound layer, it is preferable that the organic compound layer, particularly the hole transport layer, be thinly formed on the sidewalls of the pixel separation layer. Specifically, the thickness of the sidewalls can be made thin by increasing the taper angle of the sidewalls of the pixel separation layer or the thickness of the pixel separation layer, thereby increasing vignetting during deposition.

[0205] On the other hand, it is preferable to adjust the sidewall taper angle and film thickness of the pixel separation layer to such an extent that voids are not formed in the protective layer formed thereon. Since voids are not formed in the protective layer, the occurrence of defects in the protective layer can be reduced. Since the occurrence of defects in the protective layer is reduced, deterioration of reliability such as the occurrence of dark spots and poor conduction of the second electrode can be reduced.

[0206] According to this embodiment, charge leakage to adjacent pixels can be effectively suppressed even if the taper angle of the sidewall of the pixel separation layer is not steep. As a result of this study, it was found that a taper angle in the range of 60 degrees to 90 degrees can sufficiently reduce charge leakage. The thickness of the pixel separation layer is preferably 10 nm to 150 nm. Similar effects can also be achieved even if the pixel separation layer is composed only of pixel electrodes without a pixel separation layer. However, in this case, it is preferable to make the thickness of the pixel electrode less than half that of the organic layer or to make the edge of the pixel electrode forward tapered at less than 60 degrees, as this reduces short circuits in the organic light-emitting element.

[0207] [Organic compound layer] The organic compound layer may be formed as a single layer or as multiple layers. When multiple layers are included, they may be called hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole blocking layer, electron transport layer, or electron injection layer depending on their functions. The organic compound layer is mainly composed of organic compounds but may also contain inorganic atoms or inorganic compounds. For example, the organic compound layer may contain copper, lithium, magnesium, aluminum, iridium, platinum, molybdenum, zinc, or the like. The organic compound layer may be disposed between the first electrode and the second electrode, or may be disposed in contact with the first electrode and the second electrode.

[0208] When the device has multiple light-emitting layers, a charge generation portion may be provided between the first and second light-emitting layers. The charge generation portion may have an organic compound with a lowest unoccupied molecular orbital energy (LUMO) of -5.0 eV or less. The same applies when the charge generation portion is provided between the second and third light-emitting layers.

[0209] [Protective layer] A protective layer may be provided on the second electrode. For example, by adhering glass with a moisture absorbent on the second electrode, the intrusion of water and other contaminants into the organic compound layer can be reduced, thereby reducing the occurrence of display defects. In another embodiment, a passivation film such as silicon nitride may be provided on the cathode to reduce the intrusion of water and other contaminants into the organic compound layer. For example, after forming the cathode, the cathode may be transferred to another chamber without breaking the vacuum, and a 2 μm-thick silicon nitride film may be formed by CVD to serve as a protective layer. A protective layer may be provided using atomic layer deposition (ALD) after the CVD film formation. The material of the film formed by ALD is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, or the like. Silicon nitride may be further formed on the film formed by ALD by CVD. The film formed by ALD may have a thickness smaller than that of the film formed by CVD. Specifically, the thickness may be 50% or less, or even 10% or less.

[0210] [Color Filter] A color filter may be provided on the protective layer. For example, a color filter taking into consideration the size of the organic light-emitting element may be provided on a separate substrate and then bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer described above using photolithography technology. The color filter may be made of a polymer.

[0211] [Planarization layer] A planarization layer may be provided between the color filter and the protective layer. The planarization layer is provided for the purpose of reducing the unevenness of the underlying layer. It may also be called a material resin layer without limiting its purpose. The planarization layer may be composed of an organic compound, and may be either a low molecular weight or a high molecular weight, but a high molecular weight is preferred.

[0212] The planarizing layer may be provided above or below the color filter, and may be made of the same or different materials, such as polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0213] [Microlens] The organic light-emitting device may have an optical component such as a microlens on its light-emitting side. The microlens may be made of acrylic resin, epoxy resin, or the like. The microlens may be used to increase the amount of light extracted from the organic light-emitting device and to control the direction of the extracted light. The microlens may have a hemispherical shape. When the microlens has a hemispherical shape, among the tangents to the hemisphere, there is a tangent that is parallel to the insulating layer, and the point of contact between this tangent and the hemisphere is the vertex of the microlens. The vertex of the microlens can be determined in the same way in any cross-sectional view. In other words, among the tangents to the semicircle of the microlens in the cross-sectional view, there is a tangent that is parallel to the insulating layer, and the point of contact between this tangent and the semicircle is the vertex of the microlens.

[0214] It is also possible to define the midpoint of a microlens. In the cross section of the microlens, a line segment is imagined from the point where an arc shape ends to the point where another arc shape ends, and the midpoint of this line segment can be called the midpoint of the microlens. The cross section for determining the vertex and midpoint may be a cross section perpendicular to the insulating layer.

[0215] The microlens has a first surface having a convex portion and a second surface opposite the first surface. The second surface is preferably disposed closer to the functional layer than the first surface. To achieve this configuration, the microlens must be formed on the light-emitting device. When the functional layer is an organic layer, it is preferable to avoid processes that result in high temperatures during the manufacturing process. Furthermore, when the second surface is disposed closer to the functional layer than the first surface, it is preferable that the glass transition temperatures of all organic compounds constituting the organic layer are 100°C or higher, and more preferably 130°C or higher.

[0216] [Counter substrate] An opposing substrate may be provided on the planarization layer. The opposing substrate is called an opposing substrate because it is provided at a position corresponding to the aforementioned substrate. The constituent material of the opposing substrate may be the same as that of the aforementioned substrate. When the aforementioned substrate is defined as a first substrate, the opposing substrate may be a second substrate.

[0217] [Organic layer] 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 are formed by the method shown below.

[0218] The organic compound layer constituting the organic light-emitting device according to this embodiment can be formed by dry processes such as vacuum deposition, ionization deposition, sputtering, plasma, etc. 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 (for example, spin coating, dipping, casting, LB method, inkjet method, etc.).

[0219] Here, when a layer is formed by a vacuum deposition method or a solution coating method, crystallization is unlikely to occur and the layer has excellent stability over time. When a film is formed by a coating method, the film can be formed by combining with an appropriate binder resin.

[0220] Examples of the binder resin include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0221] These binder resins may be used singly or in combination as homopolymers or copolymers, and may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, if necessary.

[0222] [Pixel circuit] The light-emitting device may have a pixel circuit connected to the light-emitting element. The pixel circuit may be an active matrix type that controls the emission of the first light-emitting element and the second light-emitting element independently. The active matrix type circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light-emitting element, a transistor that controls the emission brightness of the light-emitting element, a transistor that controls the emission timing, a capacitor that holds the gate voltage of the transistor that controls the emission brightness, and a transistor for connecting to GND without going through the light-emitting element.

[0223] The light-emitting device has a display region and a peripheral region arranged around the display region. The display region has pixel circuits, and the peripheral region has a display control circuit. The mobility of a transistor constituting the pixel circuit may be lower than the mobility of a transistor constituting the display control circuit.

[0224] The slope of the current-voltage characteristics of the transistors that make up the pixel circuit may be smaller than the slope of the current-voltage characteristics of the transistors that make up the display control circuit. The slope of the current-voltage characteristics can be measured using the so-called Vg-Ig characteristics.

[0225] The transistors that make up the pixel circuit are transistors connected to light-emitting elements such as the first light-emitting element.

[0226] [Pixels] An organic light emitting device includes a plurality of pixels, each of which includes sub-pixels that emit different colors, for example, RGB colors.

[0227] The pixel emits light from an area called the pixel aperture. This area is the same as the first area. The pixel aperture may be 15 μm or less, or 5 μm or more. More specifically, it may be 11 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc.

[0228] The distance between the subpixels may be 10 μm or less, and specifically may be 8 μm, 7.4 μm, or 6.4 μm.

[0229] The pixels may be arranged in a known manner in a plan view. For example, they may be in a stripe arrangement, a delta arrangement, a pentile arrangement, or a Bayer arrangement. The shape of the subpixels in a plan view may be any known shape. For example, they may be rectangular, quadrilaterals such as diamonds, or hexagons. Of course, a shape that is close to a rectangle, rather than an exact shape, is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[0230] [Uses of the organic light-emitting device according to this embodiment] The organic light-emitting device according to this embodiment can be used as a component of a display device or a lighting device, and can also be used as an exposure light source for an electrophotographic image forming device, a backlight for a liquid crystal display device, or a light-emitting device having a white light source and a color filter.

[0231] The display device may be an image information processing device that has an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., has an information processing unit that processes the input information, and displays the input image on the display unit.

[0232] 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.

[0233] Next, the display device according to this embodiment will be described with reference to the drawings.

[0234] 1 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).

[0235] FIG. 1(a) shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel includes subpixels 10. The subpixels 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 subpixels may be selectively transmitted or color-converted using a color filter or the like. Each subpixel includes a reflective electrode 2, which serves as a first electrode, on an interlayer insulating layer 1; an insulating layer 3 covering the edges 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.

[0236] 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).

[0237] 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.

[0238] 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 .

[0239] The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0240] 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.

[0241] 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.

[0242] The display device 100 in FIG. 1(b) includes an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 made of glass, silicon, or the like is provided with an insulating layer 12 on top of it. An active element 18 such as a TFT is disposed on the insulating layer, and a gate electrode 13, a gate insulating film 14, and a semiconductor layer 15 of the active element are disposed on top of it. The TFT 18 also includes the semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is disposed on top of the TFT 18. An anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20 provided in the insulating film.

[0243] The electrical connection between the electrodes (anode, cathode) included in the organic light-emitting element 26 and the electrodes (source electrode, drain electrode) included in the TFT is not limited to the embodiment shown in Fig. 1(b). In other words, it is sufficient that either the anode or the cathode is electrically connected to either the TFT source electrode or the drain electrode. TFT stands for thin film transistor.

[0244] 1(b), the organic compound layer 22 is illustrated as a single layer, but the organic compound layer 22 may be a multi-layer structure. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce deterioration of the organic light-emitting element.

[0245] Although the display device 100 in FIG. 1(b) uses transistors as switching elements, other switching elements may be used instead.

[0246] The transistors used in the display device 100 of Fig. 1(b) are not limited to transistors using single-crystal silicon wafers, but may also be thin-film transistors having an active layer on an insulating surface of a substrate. Examples of active layers include single-crystal silicon, amorphous silicon, microcrystalline silicon, and other non-single-crystal silicon, as well as non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Thin-film transistors are also called TFT elements.

[0247] The transistors included in the display device 100 of Fig. 1(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 integrally formed.

[0248] 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.

[0249] 2 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.

[0250] 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.

[0251] The display device according to the present embodiment may be used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display.

[0252] 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 a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0253] 3A 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.

[0254] 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 the present invention. This is because the organic light-emitting element has a fast response speed. A display device using an organic light-emitting element can be used more preferably than a liquid crystal display device, which requires a high display speed.

[0255] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0256] FIG. 3(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 unlock the device, etc. An electronic device having a communication unit can also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. An image captured by the camera function is displayed on the display unit. Examples of the electronic device include a smartphone and a laptop computer.

[0257] 4A and 4B are schematic diagrams illustrating an example of a display device according to this embodiment. Fig. 4A shows 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 light-emitting device according to this embodiment may be used in the display unit 1302.

[0258] It has a frame 1301 and a base 1303 that supports a display unit 1302. The base 1303 is not limited to the form shown in Fig. 4(a). The bottom side of the frame 1301 may also serve as the base.

[0259] The frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0260] FIG. 4(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in FIG. 4(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.

[0261] FIG. 5(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, and a light diffusion unit 1405. The light source 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 output side of the lighting. If necessary, a cover may be provided on the outermost part.

[0262] The lighting device is, for example, a device for illuminating 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 these colors. The lighting device may have the organic light-emitting element of the present invention and a power supply circuit connected thereto. The power supply circuit is a circuit for converting 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.

[0263] 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.

[0264] 5(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.

[0265] A tail lamp 1501 may include an organic light-emitting element according to this embodiment. The tail lamp 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.

[0266] An automobile 1500 may have a body 1503 and a window 1502 attached thereto. The window 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, constituent materials of the electrodes and the like of the organic light-emitting element are made of transparent materials.

[0267] The moving body according to this embodiment includes one or both of a driving force generating unit that generates a driving force that is mainly used to move the moving body, and a rotating body that is mainly used to move the moving body. The driving force generating unit may be an engine, a motor, or the like. The rotating body may be a tire, a wheel, a ship's propeller, or the like. Specifically, the moving body may be a bicycle, an automobile, a train, a ship, an airplane, 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 an organic light-emitting element according to this embodiment.

[0268] An application example of the display device of each of the above-described embodiments will be described with reference to Fig. 6. 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. An image capturing and displaying device used in such an application example includes an image capturing device capable of photoelectrically converting visible light and a displaying device capable of emitting visible light.

[0269] 6(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.

[0270] 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.

[0271] FIG. 6(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 include a control device 1612. The control device 1612 is equipped with an imaging device equivalent to the imaging device 1602 and a display device. A lens 1611 is formed with an optical system for projecting light emitted by the display device in 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.

[0272] 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.

[0273] 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.

[0274] The display device according to this embodiment 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.

[0275] Specifically, the display device determines a first display area on which the user gazes and a second display area other than the first display area based on the line-of-sight information. The first display area and the second display 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 display area may be controlled to be higher than the display resolution of the second display area. In other words, the resolution of the second display area may be lower than that of the first field of view area.

[0276] 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.

[0277] Note that AI may be used to determine the first display area and the area 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 the image of the eyeball, using as training data an image of the eyeball and the actual direction in which the eyeball in the image was looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in the external device, it is transmitted to the display device via communication.

[0278] 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.

[0279] 7A and 7B show an image forming apparatus according to this embodiment. Fig. 7A is a schematic diagram of an image forming apparatus 36 according to this embodiment. The image forming apparatus has a photosensitive member, an exposure light source, a developing unit, a charging unit, a transfer unit, a transport roller, and a fixing unit.

[0280] Light 29 is irradiated from an exposure light source 28, and an electrostatic latent image is formed on the surface of the photosensitive member 27. This exposure light source has an organic light-emitting element according to the present invention. A developing unit 31 has toner and the like. A charging unit 30 charges the photosensitive member. A transfer device 32 transfers the developed image to a recording medium 34. A transport unit 33 transports the recording medium 34. The recording medium 34 is, for example, paper. A fixing unit 35 fixes the image formed on the recording medium.

[0281] 7(b) and 7(c) are schematic diagrams showing exposure light source 28 with multiple light-emitting units 38 arranged on a long substrate. 37 is a direction parallel to the axis of the photoconductor, and represents the column direction in which the organic light-emitting elements are arranged. This column direction is the same as the axis direction about which photoconductor 27 rotates. This direction can also be called the long axis direction of the photoconductor.

[0282] Figure 7(b) shows a configuration in which the light-emitting units are arranged along the longitudinal axis of the photoconductor. Figure 7(c) shows a different configuration from (b), in which the light-emitting units 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.

[0283] The first column has a plurality of light-emitting units arranged at intervals. The second column has light-emitting units at positions corresponding to the intervals between the light-emitting units in the first column. That is, the plurality of light-emitting units are also arranged at intervals in the row direction.

[0284] The arrangement in FIG. 7(c) can also be described as a grid arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0285] 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]

[0286] Examples are shown below, but the present invention is not limited to the following contents.

[0287] [Example 1] In this example, a top-emission stacked organic light-emitting device was fabricated by sequentially forming an anode as a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a cathode as a second electrode on a substrate. A blue light-emitting layer was provided in the first light-emitting unit, and a yellow light-emitting layer was provided in the second light-emitting unit, thereby fabricating an organic light-emitting device with a double-sided emission structure.

[0288] 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 in this manner was used as the ITO substrate. Next, the first light-emitting unit, charge generation layer, second light-emitting unit, and cathode shown in Table 3 below were formed in this order on the ITO substrate by vacuum deposition using resistance heating in a vacuum chamber. At this time, the electrode areas of the opposing electrodes (anode and cathode) were set to 3 mm2. 2 After the layers up to the cathode were formed, the substrate was transferred to a glove box and sealed with a glass cap containing a desiccant in a nitrogen atmosphere, to obtain a stacked organic light-emitting device.

[0289] [Table 3]

[0290] [Examples 2 to 14, Comparative Examples 1 to 3] For Examples 2, 4 to 14 and Comparative Examples 1 to 3, organic light-emitting devices were produced in the same manner as in Example 1, except that the compounds listed in Table 4 were changed. For Example 3, the compounds listed in Table 4 were used, and 49% of EM11 in the second light-emitting section of Example 1 was replaced with EM30.

[0291] The voltage-current characteristics of the obtained organic light-emitting devices were measured using a microcurrent meter 4140B manufactured by Hewlett-Packard, and the emission spectrum was measured using an SR-3 manufactured by Topcon. The organic light-emitting devices of Examples 1 to 8 exhibited good white light emission. 2 The organic light-emitting device was subjected to a driving test under the constant current condition of 100 V, and the luminous efficiency and driving voltage were evaluated. The results are shown in Table 5.

[0292] The voltage ratio is a relative value when the drive voltage of Comparative Example 1 is set to 1.0. The efficiency ratio is a relative value when the luminous efficiency of Comparative Example 1 is set to 1.0.

[0293] In addition, ΔHOMO, ΔHOMO(1), ΔHOMO(2), ΔLUMO, and ΔLUMO(1) in the table are as follows. ΔHOMO = HOMO(B) - HOMO(A) ΔHOMO(1) = HOMO(F) - HOMO(E) ΔHOMO(2) = HOMO(E) - HOMO(G) ΔLUMO = LUMO(D) - LUMO(C) ΔLUMO(1) = LUMO(E) - LUMO(F) ΔLUMO(2)=LUMO(H)-LUMO(E)

[0294] [Table 4]

[0295] [Table 5]

[0296] Table 5 shows that the organic light-emitting devices of Examples 1 to 14 exhibited low driving voltages because they satisfied ΔHOMO≧0 eV. Among them, the organic light-emitting devices of Examples 1 to 10 were configured such that the holes generated in the charge generating layer were less likely to remain in the charge generating layer due to the good hole injection properties of the first emitting layer of the second emitting unit. As a result, they exhibited lower driving voltages. On the other hand, the organic light-emitting devices of Comparative Examples 1 to 3 did not satisfy ΔHOMO≧0 eV and therefore exhibited high driving voltages. The organic light-emitting devices of Comparative Examples 1 to 3 exhibited high driving voltages because the hole injection properties of the first emitting layer of the second emitting unit were poor.

[0297] Furthermore, organic light-emitting devices that satisfy ΔHOMO(1) > 0 eV exhibited higher luminous efficiency. In other words, the high hole-trapping ability of the second emitting layer in the first emitting unit enabled the production of organic light-emitting devices with higher luminous efficiency. This is because the ability to trap holes in the second emitting layer reduces hole leakage from the second emitting layer.

[0298] Furthermore, organic light-emitting devices that satisfy ΔLUMO(2)≧0 eV exhibited lower driving voltages and higher luminous efficiencies. In other words, the high electron injection ability of the second emitting layer in the first emitting unit enabled the production of organic light-emitting devices that exhibited lower driving voltages and higher luminous efficiencies. This is because electrons generated from the charge generating layer can be more efficiently injected into the second emitting layer.

[0299] Furthermore, organic light-emitting devices that satisfy ΔHOMO(2)≧0 eV exhibited lower driving voltages and higher luminous efficiency. In other words, the high hole injection ability of the second emitting layer in the first emitting unit enabled the production of organic light-emitting devices that exhibited lower driving voltages and higher luminous efficiency. This is because holes generated from the anode can be more efficiently injected into the second emitting layer.

[0300] Furthermore, organic light-emitting devices that satisfy ΔLUMO(1) > 0 eV exhibited lower driving voltages. In other words, the high electron trapping ability of the second light-emitting layer in the first light-emitting unit enabled the production of organic light-emitting devices that exhibited lower driving voltages.

[0301] In this example, the first compound is a compound contained in the second electron blocking layer, the second compound is an assist material or host material contained in the first emitting layer, the third compound is a host material contained in the first emitting layer, the fourth compound is a compound contained in the second hole blocking layer, the fifth compound is a host material contained in the second emitting layer, the sixth compound is a guest material contained in the second emitting layer, the seventh compound is a compound contained in the first electron blocking layer, and the eighth compound is a compound contained in the first hole blocking layer.

[0302] [Examples 15 to 24] The organic light-emitting device according to Example 15 was fabricated by the following procedure.

[0303] In this example, a top-emission stacked organic light-emitting device was fabricated by sequentially forming an anode as a first electrode, a first light-emitting unit, a charge generation layer, a second light-emitting unit, and a cathode as a second electrode on a substrate. A blue light-emitting layer was used for the first light-emitting unit, and a yellow light-emitting layer was used for the second light-emitting unit, forming these layers in this order. This organic light-emitting device had a double-sided emission structure.

[0304] 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 in this manner was used as the ITO substrate. Next, the first light-emitting unit, charge generation layer, second light-emitting unit, and cathode shown in Table 6 below were formed in this order on the ITO substrate by vacuum deposition using resistance heating in a vacuum chamber. At this time, the electrode areas of the opposing electrodes (anode and cathode) were set to 3 mm2. 2 After the layers up to the cathode were formed, the substrate was transferred to a glove box and sealed with a glass cap containing a desiccant in a nitrogen atmosphere, to obtain a stacked organic light-emitting device.

[0305] [Table 6]

[0306] Organic light-emitting devices of Examples 16 to 24 were prepared in the same manner as in Example 15, except that the organic compound used in Example 15 was changed to an organic compound listed in Table 4. The HOMO levels and LUMO levels of the organic compounds used in these Examples are shown in Table 7. The unit is eV. In Example 23, an organic light-emitting device was prepared in the same manner as in Example 15, except that the first hole blocking layer and second hole blocking layer of Example 15 were changed to ET24. In Example 24, an organic light-emitting device was prepared in the same manner as in Example 15, except that the second light-emitting layer and third light-emitting layer of Example 1 were changed to the first light-emitting layer.

[0307] The voltage-current characteristics of the obtained organic light-emitting devices were measured using a microcurrent meter "4140B" manufactured by Hewlett-Packard, and the emission spectrum was measured using an "SR-3" manufactured by Topcon. The organic light-emitting devices of Examples 1 to 10 exhibited good white light emission. 2 A drive test of the organic light-emitting device was performed under a constant current condition of 100 V, and the LT80, which is the time it takes for the luminance to deteriorate by 20% from the initial luminance, and the drive voltage were evaluated. The results are shown in Table 8. The efficiency ratio and durability ratio values ​​are relative values ​​when the LT80 and efficiency of Comparative Example 4 are set to 1.0.

[0308] In Table 8, ΔHOMO(Hα), ΔHOMO(Hβ), and ΔLUMO are respectively represented by the following formulas. ΔHOMO(Hα)=HOMO(F)-HOMO(E) ΔHOMO(Hβ) = HOMO(B) - HOMO(A) ΔLUMO = LUMO(D) - LUMO(C)

[0309] [Table 7]

[0310] [Table 8]

[0311] As can be seen from Table 8, in Examples 15 to 24, the hole-trapping ability of the first light-emitting layer of the second light-emitting unit between the charge generation layer and the anode was improved, thereby suppressing deterioration caused by the charge generation layer and thus suppressing deterioration of the organic light-emitting device. Furthermore, by injecting charges into the light-emitting layer without allowing them to accumulate around the charge generation layer, the durability of the light-emitting layer can be improved and high efficiency can be achieved at the same time.

[0312] As shown in Examples 15 to 19, by using a pyrene derivative, a perylene derivative, an anthracene derivative, or a fluoranthene derivative as the fifth compound in the first light-emitting layer, the durability of the light emission itself is improved and the effects of the present invention can be more effectively exhibited. This is because these compounds are compounds consisting of carbon-carbon bonds and do not have a carbon-nitrogen bond with low bond energy like EM33 used in Example 20.

[0313] Furthermore, by increasing the hole-trapping ability of the first light-emitting unit as in Examples 15 to 19, holes generated from the charge generation layer can be smoothly injected into the light-emitting layer of the first light-emitting unit, and electrons and holes generated from the charge generation layer can be prevented from remaining around the charge generation layer, thereby enhancing the effects of the present invention.

[0314] Furthermore, compared to when the ΔHOMO(Hα) of the first light-emitting unit is lower than 0.2 eV, as in Example 21, when the ΔHOMO(Hα) is 0.2 eV or higher, as in Examples 15 and 16, the effects of the present invention can be more effectively achieved.

[0315] As described above, the organic light-emitting device according to the present invention is an organic light-emitting device that exhibits a low driving voltage. Furthermore, the organic light-emitting device according to this embodiment exhibits higher luminous efficiency. Furthermore, the organic light-emitting device according to this embodiment exhibits superior durability.

[0316] The present invention can also have the following configuration.

[0317] (Configuration 1) An organic light-emitting device having a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a second electrode in this order, the second light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer in this order from the first electrode side; the first organic layer has a first compound, the first light-emitting layer has a second compound and a third compound, and the second organic layer has a fourth compound; An organic light-emitting device, wherein the first compound and the second compound satisfy the relationship (a). (a) HOMO(B)-HOMO(A)≧0 eV HOMO(A) and HOMO(B) respectively represent the HOMO energy level of the first compound and the HOMO energy level of the second compound.

[0318] (Configuration 2) The organic light-emitting device according to configuration 1, wherein the first compound, the second compound, the third compound, and the fourth compound satisfy the relationship (a1). (a1) HOMO(B)-HOMO(A)>LUMO(D)-LUMO(C) HOMO(A), HOMO(B), LUMO(C), and LUMO(D) respectively represent the HOMO energy level of the first compound, the HOMO energy level of the second compound, the LUMO energy level of the third compound, and the LUMO energy level of the fourth compound.

[0319] (Configuration 3) the first light-emitting layer has a first light-emitting portion and a second light-emitting portion, 3. The organic light-emitting device according to claim 1, wherein the first light-emitting portion includes the second compound, and the second light-emitting portion includes the third compound.

[0320] (Configuration 4) An organic light-emitting device having, in this order, a first electrode, a first light-emitting unit, a first charge generation layer, a third light-emitting unit, a second charge generation layer, a second light-emitting unit, and a second electrode, the second light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer in this order from the first electrode side; the first organic layer has a first compound, the first light-emitting layer has a second compound and a third compound, and the second organic layer has a fourth compound; An organic light-emitting device, wherein the first compound and the second compound satisfy the relationship (a). (a) HOMO(B)-HOMO(A)≧0 eV HOMO(A) and HOMO(B) respectively represent the HOMO energy level of the first compound and the HOMO energy level of the second compound.

[0321] (Configuration 5) 5. The organic light-emitting device according to configuration 4, wherein the first compound, the second compound, the third compound, and the fourth compound satisfy the relationship (a1). (a1) HOMO(B)-HOMO(A)>LUMO(D)-LUMO(C) HOMO(A), HOMO(B), LUMO(C), and LUMO(D) respectively represent the HOMO energy level of the first compound, the HOMO energy level of the second compound, the LUMO energy level of the third compound, and the LUMO energy level of the fourth compound.

[0322] (Configuration 6) the third light-emitting unit has a fifth organic layer, a third light-emitting layer, and a sixth organic layer in this order from the first electrode side, the fifth organic layer comprises a ninth compound; the third light-emitting layer comprises a tenth compound; the sixth organic layer comprises an eleventh compound, 6. The organic light-emitting device according to configuration 4 or 5, wherein the ninth compound, the tenth compound, and the eleventh compound satisfy the relationships (f) and (g). (f) HOMO(J)-HOMO(I)≧0 eV (g) LUMO(K)-LUMO(J)≧0 eV HOMO(I), HOMO(J), LUMO(J), and LUMO(K) respectively represent the HOMO energy level of the ninth compound, the HOMO energy level of the tenth compound, the LUMO energy level of the tenth compound, and the LUMO energy level of the eleventh compound.

[0323] (Configuration 7) the first light-emitting layer has a first light-emitting portion and a second light-emitting portion, 7. The organic light-emitting element according to any one of Structures 4 to 6, wherein the first light-emitting portion includes the second compound, and the second light-emitting portion includes the third compound.

[0324] (Configuration 8) 8. The organic light-emitting element according to any one of Structures 1 to 7, wherein the first organic layer and the first light-emitting layer are in contact with each other, and the first light-emitting layer and the second organic layer are in contact with each other.

[0325] (Configuration 9) The organic light-emitting element according to configuration 3 or 7, wherein the first organic layer and the first light-emitting section are in contact with each other, the first light-emitting section and the second light-emitting section are in contact with each other, and the second light-emitting section and the second organic layer are in contact with each other.

[0326] (Configuration 10) the first light-emitting unit has a third organic layer, a second light-emitting layer, and a fourth organic layer in this order; the third organic layer has a seventh compound, the second light-emitting layer has a fifth compound and a sixth compound, and the fourth organic layer has an eighth compound; 10. The organic light-emitting device according to any one of configurations 1 to 9, wherein the fifth compound and the eighth compound satisfy the relationship (b). (b) LUMO(H)-LUMO(E)≧0 eV LUMO(E) and LUMO(H) respectively represent the LUMO energy level of the fifth compound and the LUMO energy level of the eighth compound.

[0327] (Configuration 11) 11. The organic light-emitting device according to configuration 10, wherein the fifth compound, the seventh compound, and the eighth compound satisfy the relationship (b1). (b1) LUMO(H)-LUMO(E)>HOMO(E)-HOMO(G) HOMO(E), LUMO(E), HOMO(G), and LUMO(H) respectively represent the HOMO energy level of the fifth compound, the LUMO energy level of the fifth compound, the HOMO energy level of the seventh compound, and the LUMO energy level of the eighth compound.

[0328] (Configuration 12) the first light-emitting unit has a second light-emitting layer; the second light-emitting layer includes a fifth compound and a sixth compound; 10. The organic light-emitting device according to any one of configurations 1 to 9, wherein the fifth compound and the sixth compound satisfy the relationship (c). (c) HOMO(F)>HOMO(E) HOMO(E) and HOMO(F) respectively represent the HOMO energy level of the fifth compound and the HOMO energy level of the sixth compound.

[0329] (Configuration 13) 13. The organic light-emitting device according to claim 12, wherein the content of the sixth compound in the second light-emitting layer is less than the content of the fifth compound.

[0330] (Configuration 14) the first light-emitting unit has a third organic layer, a second light-emitting layer, and a fourth organic layer in this order; the third organic layer has a seventh compound, the second light-emitting layer has a fifth compound and a sixth compound, and the fourth organic layer has an eighth compound; 10. The organic light-emitting device according to any one of configurations 1 to 9, wherein the fifth compound and the eighth compound satisfy the relationship (b). (d) HOMO(E)-HOMO(G)≧0 eV HOMO(E) and HOMO(G) respectively represent the HOMO energy level of the fifth compound and the HOMO energy level of the seventh compound.

[0331] (Configuration 15) 15. The organic light-emitting device according to configuration 14, wherein the fifth compound, the seventh compound, and the eighth compound satisfy the relationship (d1). (d1) HOMO(E)-HOMO(G)>LUMO(H)-LUMO(E) HOMO(E), LUMO(E), HOMO(G), and LUMO(H) respectively represent the HOMO energy level of the fifth compound, the LUMO energy level of the fifth compound, the HOMO energy level of the seventh compound, and the LUMO energy level of the eighth compound.

[0332] (Configuration 16) 11. The organic light-emitting device according to configuration 10, wherein the third organic layer and the second light-emitting layer are in contact with each other, and the second light-emitting layer and the fourth organic layer are in contact with each other.

[0333] (Configuration 17) 13. The organic light-emitting device according to configuration 12, wherein the fifth compound and the sixth compound satisfy the relationship (c1). (c1) HOMO(F)-HOMO(E)≧0.15 eV (Configuration 18) 18. The organic light-emitting device according to any one of structures 1 to 17, wherein the third compound is a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent.

[0334] (Configuration 19) 19. The organic light-emitting device according to configuration 18, wherein the optionally substituted fused polycyclic hydrocarbon skeleton has 10 to 25 carbon atoms.

[0335] (Configuration 20) 19. The organic light-emitting device according to claim 18, wherein the fused polycyclic hydrocarbon skeleton, which may have a substituent, is any one of a naphthalene skeleton, a fluorene skeleton, an anthracene skeleton, a phenanthrene skeleton, a pyrene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a fluoranthene skeleton, and a perylene skeleton.

[0336] (Configuration 21) 21. The organic light-emitting device according to any one of Structures 18 to 20, wherein the heterocyclic skeleton which may have a substituent has 3 to 30 carbon atoms.

[0337] (Configuration 22) 22. The organic light-emitting element according to any one of structures 18 to 21, wherein the heterocyclic skeleton which may have a substituent is any one of a dibenzofuran skeleton, a dibenzothiophene skeleton, a xanthone skeleton, a thioxanthone skeleton, a carbazole skeleton, an indolocarbazole skeleton, and a triazine skeleton.

[0338] (Configuration 23) 23. The organic light-emitting device according to any one of structures 1 to 22, wherein the freely rotatable single bond of the third compound is a carbon-carbon bond.

[0339] (Configuration 24) 4. The organic light-emitting element according to configuration 3, wherein the second light-emitting portion further comprises the second compound.

[0340] (Configuration 25) the first light-emitting unit has a second light-emitting layer; the first light-emitting layer comprises a first light-emitting material, and the second light-emitting layer comprises a third light-emitting material; 25. The organic light-emitting element according to any one of structures 1 to 24, wherein the first light-emitting material is a phosphorescent material, and the third light-emitting material is a fluorescent material.

[0341] (Configuration 26) the first light-emitting unit has a second light-emitting layer; the first light-emitting portion includes a first light-emitting material, the second light-emitting portion includes a second light-emitting material, and the second light-emitting layer includes a third light-emitting material; 4. The organic light-emitting device according to configuration 3, wherein the first light-emitting material and the second light-emitting material are phosphorescent materials, and the third light-emitting material is a fluorescent material.

[0342] (Configuration 27) A display device having a plurality of pixels, at least one of the plurality of pixels having an organic light-emitting element according to any one of structures 1 to 26 and a transistor connected to the organic light-emitting element.

[0343] (Configuration 28) 27. A display device comprising: a display unit having the organic light-emitting element according to any one of configurations 1 to 26; and a housing in which the display unit is provided.

[0344] (Configuration 29) an imaging element that receives light; and a display unit that displays an image captured by the imaging element; 27. A photoelectric conversion device, wherein the display section comprises the organic light-emitting element according to any one of the first to twenty-sixth embodiments.

[0345] (Configuration 30) 27. An electronic device comprising: a display unit having the organic light-emitting element according to any one of configurations 1 to 26; a housing in which the display unit is provided; and a communication unit provided in the housing for communicating with an external device.

[0346] (Configuration 31) A wearable device comprising: a display unit having the organic light-emitting element according to any one of configurations 1 to 26; an optical system that collects light from the display unit; and a control device that controls the display of the display unit.

[0347] (Configuration 32) 27. A lighting device comprising: a light source having the organic light-emitting element according to any one of configurations 1 to 26; and a housing in which the light source is provided.

[0348] (Configuration 33) A moving body comprising: a lighting fixture having the organic light-emitting element according to any one of configurations 1 to 26; and a vehicle on which the lighting fixture is provided.

[0349] (Configuration 34) a photosensitive member and an exposure light source that exposes the photosensitive member; 27. An image forming apparatus, wherein the exposure light source comprises the organic light-emitting element according to any one of the first to twenty-sixth embodiments. [Explanation of symbols]

[0350] 200 1st electrode 300 First Light Emitting Unit 303 Third organic layer 304 Second light-emitting layer 305 4th organic layer 400 Charge generation layer 500 Second Light Emitting Unit 502 1st organic layer 503 First light-emitting layer 504 2nd organic layer 600 2nd electrode

Claims

1. An organic light-emitting device having a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a second electrode in this order, the second light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer in this order from the first electrode side; the first organic layer has a first compound, the first light-emitting layer has a second compound and a third compound, and the second organic layer has a fourth compound; The organic light-emitting element is characterized in that the first compound and the second compound satisfy the relationship (a). (a) HOMO(B)-HOMO(A)≧0eV HOMO(A) and HOMO(B) respectively represent the HOMO energy level of the first compound and the HOMO energy level of the second compound.

2. The organic light-emitting device according to claim 1 , wherein the first compound, the second compound, the third compound, and the fourth compound satisfy the relationship (a1). (a1) HOMO (B) - HOMO (A) > LUMO (D) - LUMO (C) HOMO(A), HOMO(B), LUMO(C), and LUMO(D) respectively represent the HOMO energy level of the first compound, the HOMO energy level of the second compound, the LUMO energy level of the third compound, and the LUMO energy level of the fourth compound.

3. the first light-emitting layer has a first light-emitting portion and a second light-emitting portion, The organic light emitting device according to claim 1 , wherein the first light emitting portion includes the second compound, and the second light emitting portion includes the third compound.

4. An organic light-emitting device having a first electrode, a first light-emitting unit, a first charge generation layer, a third light-emitting unit, a second charge generation layer, a second light-emitting unit, and a second electrode in this order, the second light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer in this order from the first electrode side; the first organic layer has a first compound, the first light-emitting layer has a second compound and a third compound, and the second organic layer has a fourth compound; The organic light-emitting element is characterized in that the first compound and the second compound satisfy the relationship (a). (a) HOMO(B)-HOMO(A)≧0eV HOMO(A) and HOMO(B) respectively represent the HOMO energy level of the first compound and the HOMO energy level of the second compound.

5. The organic light-emitting device according to claim 4 , wherein the first compound, the second compound, the third compound, and the fourth compound satisfy the relationship (a1). (a1) HOMO (B) - HOMO (A) > LUMO (D) - LUMO (C) HOMO(A), HOMO(B), LUMO(C), and LUMO(D) respectively represent the HOMO energy level of the first compound, the HOMO energy level of the second compound, the LUMO energy level of the third compound, and the LUMO energy level of the fourth compound.

6. the third light-emitting unit includes a fifth organic layer, a third light-emitting layer, and a sixth organic layer in this order from the first electrode side, the fifth organic layer comprises a ninth compound, the third light-emitting layer comprises a tenth compound; the sixth organic layer comprises an eleventh compound, The organic light-emitting device according to claim 4 , wherein the ninth compound, the tenth compound, and the eleventh compound satisfy the relationships (f) and (g). (f) HOMO(J)-HOMO(I)≧0eV (g) LUMO(K)-LUMO(J)≧0eV HOMO(I), HOMO(J), LUMO(J), and LUMO(K) respectively represent the HOMO energy level of the ninth compound, the HOMO energy level of the tenth compound, the LUMO energy level of the tenth compound, and the LUMO energy level of the eleventh compound.

7. the first light-emitting layer has a first light-emitting portion and a second light-emitting portion, The organic light emitting device according to claim 4 , wherein the first light emitting portion includes the second compound, and the second light emitting portion includes the third compound.

8. The organic light-emitting element according to claim 1 , wherein the first organic layer and the first light-emitting layer are in contact with each other, and the first light-emitting layer and the second organic layer are in contact with each other.

9. 8. The organic light-emitting element according to claim 3, wherein the first organic layer and the first light-emitting portion are in contact with each other, the first light-emitting portion and the second light-emitting portion are in contact with each other, and the second light-emitting portion and the second organic layer are in contact with each other.

10. the first light-emitting unit has a third organic layer, a second light-emitting layer, and a fourth organic layer in this order; the third organic layer has a seventh compound, the second light-emitting layer has a fifth compound and a sixth compound, and the fourth organic layer has an eighth compound; The organic light-emitting element according to claim 1 , wherein the fifth compound and the eighth compound satisfy the relationship (b). (b) LUMO(H)-LUMO(E)≧0eV LUMO(E) and LUMO(H) respectively represent the LUMO energy level of the fifth compound and the LUMO energy level of the eighth compound.

11. The organic light-emitting device according to claim 10 , wherein the fifth compound, the seventh compound, and the eighth compound satisfy the relationship (b1). (b1) LUMO(H)-LUMO(E)>HOMO(E)-HOMO(G) HOMO(E), LUMO(E), HOMO(G), and LUMO(H) respectively represent the HOMO energy level of the fifth compound, the LUMO energy level of the fifth compound, the HOMO energy level of the seventh compound, and the LUMO energy level of the eighth compound.

12. the first light-emitting unit has a second light-emitting layer; the second light-emitting layer includes a fifth compound and a sixth compound, The organic light-emitting element according to claim 1 , wherein the fifth compound and the sixth compound satisfy the relationship (c). (c) HOMO(F)>HOMO(E) HOMO(E) and HOMO(F) respectively represent the HOMO energy level of the fifth compound and the HOMO energy level of the sixth compound.

13. The organic light-emitting device according to claim 12 , wherein the content of the sixth compound in the second light-emitting layer is less than the content of the fifth compound.

14. the first light-emitting unit has a third organic layer, a second light-emitting layer, and a fourth organic layer in this order; the third organic layer has a seventh compound, the second light-emitting layer has a fifth compound and a sixth compound, and the fourth organic layer has an eighth compound; The organic light-emitting element according to claim 1 , wherein the fifth compound and the eighth compound satisfy the relationship (b). (d) HOMO(E)-HOMO(G)≧0eV HOMO(E) and HOMO(G) respectively represent the HOMO energy level of the fifth compound and the HOMO energy level of the seventh compound.

15. The organic light-emitting device according to claim 14 , wherein the fifth compound, the seventh compound, and the eighth compound satisfy the relationship (d1). (d1) HOMO(E)-HOMO(G)>LUMO(H)-LUMO(E) HOMO(E), LUMO(E), HOMO(G), and LUMO(H) respectively represent the HOMO energy level of the fifth compound, the LUMO energy level of the fifth compound, the HOMO energy level of the seventh compound, and the LUMO energy level of the eighth compound.

16. The organic light-emitting device according to claim 10 , wherein the third organic layer and the second light-emitting layer are in contact with each other, and the second light-emitting layer and the fourth organic layer are in contact with each other.

17. The organic light-emitting device according to claim 12 , wherein the fifth compound and the sixth compound satisfy the relationship (c1). (c1) HOMO(F)-HOMO(E)≧0.15eV

18. 8. The organic light-emitting element according to claim 1, wherein the third compound is a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent.

19. 19. The organic light-emitting element according to claim 18, wherein the fused polycyclic hydrocarbon skeleton which may have a substituent has 10 to 25 carbon atoms.

20. 19. The organic light-emitting element according to claim 18, wherein the fused polycyclic hydrocarbon skeleton which may have a substituent is any one of a naphthalene skeleton, a fluorene skeleton, an anthracene skeleton, a phenanthrene skeleton, a pyrene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a fluoranthene skeleton, and a perylene skeleton.

21. 19. The organic light-emitting element according to claim 18, wherein the heterocyclic skeleton which may have a substituent has 3 to 30 carbon atoms.

22. 19. The organic light-emitting element according to claim 18, wherein the heterocyclic skeleton which may have a substituent is any one of a dibenzofuran skeleton, a dibenzothiophene skeleton, a xanthone skeleton, a thioxanthone skeleton, a carbazole skeleton, an indolocarbazole skeleton, and a triazine skeleton.

23. 8. The organic light-emitting device according to claim 1, wherein the freely rotatable single bond of the third compound is a carbon-carbon bond.

24. The organic light-emitting device according to claim 3 , wherein the second light-emitting portion further comprises the second compound.

25. the first light-emitting unit has a second light-emitting layer; the first light-emitting layer comprises a first light-emitting material, and the second light-emitting layer comprises a third light-emitting material; 8. The organic light-emitting element according to claim 1, wherein the first light-emitting material is a phosphorescent material, and the third light-emitting material is a fluorescent material.

26. the first light-emitting unit has a second light-emitting layer; the first light-emitting portion includes a first light-emitting material, the second light-emitting portion includes a second light-emitting material, and the second light-emitting layer includes a third light-emitting material; 4. The organic light-emitting element according to claim 3, wherein the first light-emitting material and the second light-emitting material are phosphorescent materials, and the third light-emitting material is a fluorescent material.

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

28. A display device comprising: a display unit having the organic light-emitting element according to claim 1; and a housing in which the display unit is provided.

29. an imaging element that receives light; and a display unit that displays an image captured by the imaging element; The photoelectric conversion device, wherein the display section comprises the organic light-emitting element according to claim 1 .

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

31. A wearable device comprising: a display unit having the organic light-emitting element according to claim 1; an optical system for concentrating light from the display unit; and a control device for controlling the display of the display unit.

32. A lighting device comprising: a light source having the organic light-emitting element according to claim 1 ; and a housing in which the light source is provided.

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

34. a photosensitive member and an exposure light source that exposes the photosensitive member; 8. An image forming apparatus, wherein the exposure light source comprises the organic light emitting element according to claim 1.

Images