Light-emitting device, electronic device, light-emitting apparatus, and lighting apparatus

Abstract

To provide a novel light-emitting device, a light-emitting device with an excellent light-emission efficiency, a light-emitting device with a desirable life, or a light-emitting device with a low driving voltage.SOLUTION: An EL layer sequentially includes a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer in ascending order of proximity to a positive electrode. The first layer includes a first organic compound and a second organic compound. The fourth layer includes a seventh organic compound. The first organic compound shows the electronic acceptability to the second organic compound. The second organic compound has an HOMO level of -5.7 eV to -5 .2 eV, both inclusive. The electron mobility when the square root of the electric field intensity [V / cm] of the seventh organic compound is 600 is in the range of 1×10-7 cm2 / Vs to 5×10-5 cm2 / Vs, both inclusive.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting element, a light-emitting device, a display module, and a lighting module , a display device, a light-emitting device, an electronic device, and a lighting device. Note that one aspect of the present invention is not limited to the above technical field. The technical field of one aspect of the invention disclosed in this specification and the like relates to an object, a method , or a manufacturing method. Alternatively, one aspect of the present invention relates to a process, a machine , a manufacture, or a composition of matter . Therefore, more specifically, the technical field of one aspect of the present invention disclosed in this specification includes semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, storage devices, imaging devices, their driving methods, or their manufacturing methods, can be cited as an example .

Background Art

[0002] The practical application of light-emitting devices (organic EL elements) using electroluminescence (EL) with organic compounds has been progressing. The basic configuration of these light-emitting devices is such that an organic compound layer (EL layer) containing a light-emitting material is sandwiched between a pair of electrodes . By applying a voltage to this element to inject carriers and utilizing the recombination energy of the carriers, light emission from the light-emitting material can be obtained.

[0003] Since such a light-emitting device is self-luminous, when used as a pixel of a display, it has advantages such as higher visibility compared to liquid crystals and the absence of a backlight, and is suitable as a flat panel display element. Also, a display using such a light-emitting device 、The fact that it can be manufactured to be thin and lightweight is also a great advantage. Furthermore, it is also one of the characteristics that the response speed is extremely fast. This is one of the characteristics.

[0004] In addition, since these light-emitting devices can form the light-emitting layer continuously in two dimensions, light emission in a planar shape can be obtained. This is a characteristic that is difficult to obtain with point light sources typified by incandescent bulbs and LEDs, or linear light sources typified by fluorescent lamps. Therefore, it has high utility value as a planar light source that can be applied to lighting and the like. This is a high utility value as a planar light source for applications such as lighting.

[0005] Displays and lighting devices using such light-emitting devices are suitable for various electronic devices, but research and development are being advanced to obtain light-emitting devices with better efficiency and longer life. Although the characteristics of the light-emitting device have been remarkably improved, it still has to be said that it is insufficient to meet the high demands for all characteristics, including efficiency and durability. This is still insufficient to meet the high demands for all characteristics, including efficiency and durability.

[0006] In Patent Document 1, a configuration is disclosed in which a hole-transporting material having a HOMO level between the HOMO level of the first hole-injecting layer and the HOMO level of the host material is provided between the first hole-transporting layer in contact with the hole-injecting layer and the light-emitting layer. This is a configuration in which a hole-transporting material having a HOMO level between the HOMO level of the first hole-injecting layer and the HOMO level of the host material is provided between the first hole-transporting layer in contact with the hole-injecting layer and the light-emitting layer. This is a configuration in which a hole-transporting material having a HOMO level between the HOMO level of the first hole-injecting layer and the HOMO level of the host material is provided between the first hole-transporting layer in contact with the hole-injecting layer and the light-emitting layer.

[0007] Although the characteristics of the light-emitting device have been remarkably improved, it still has to be said that it is insufficient to meet the high demands for all characteristics, including efficiency and durability. This is still insufficient to meet the high demands for all characteristics, including efficiency and durability.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, in one aspect of the present invention, an object is to provide a novel light-emitting device. Or, an object is to provide a light-emitting device having good luminous efficiency. Or, a light-emitting device having good lifespan. Or, an object is to provide a light-emitting device having a low driving voltage .

[0010] Or, in another aspect of the present invention, an object is to provide a highly reliable light-emitting device, electronic device, and display device, respectively. Or, in another aspect of the present invention, an object is to provide a light-emitting device, electronic device, and display device, respectively, each having low power consumption.

[0011] The present invention only needs to solve any one of the above-described problems.

Means for Solving the Problems

[0012] One aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein, in the light-emitting device in which the EL layer has a light-emitting layer, the light-emitting device has a maximum value in a degradation curve represented by a luminance change of light emission obtained when a constant current is passed through the light-emitting device.

[0013] Or, another aspect of the present invention is a light-emitting device having an anode, a cathode, and an EL layer positioned between the anode and the cathode, wherein the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer, the first layer is in contact with the anode, the first layer has a first organic compound and a second organic compound, the second layer has a third organic compound, the third layer has a fourth organic compound, the light-emitting layer has a fifth organic compound and a sixth organic compound, and the fourth layer has a seventh organic compound. ​ The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound, and the fifth organic compound is a light-emitting center substance, and the HOMO level of the second organic compound is -5. 7 eV or more and -5.2 eV or less, and the square root of the electric field strength [V / cm] of the seventh organic compound is 600, and the electron mobility is 1×10 -7 cm 2 / Vs or more and 5×10 -5 cm 2 / Vs or less, and it is a light-emitting device having a maximum value in the degradation curve represented by the luminance change of the light emission obtained when a constant current is passed through the light-emitting device.

[0014] Alternatively, another aspect of the present invention has an anode, a cathode, and an EL layer located between the anode and the cathode, and the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer. The first layer is in contact with the anode, and the first layer has a first organic compound and a second organic compound. The second layer has a third organic compound, the third layer has a fourth organic compound, the light-emitting layer has a fifth organic compound and a sixth organic compound, the fourth layer has a seventh organic compound, the first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound described above, the fifth organic compound is a light-emitting center substance, the HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, the difference between the HOMO levels of the third organic compound and the second organic compound is 0. 2 eV or less, the HOMO level of the third organic compound is the same as or deeper than the HOMO level of the second organic compound, and the square root of the electric field strength [V / cm] of the seventh organic compound is 600, and the electron mobility is 1×10 600, and the electron mobility is 1×10 -7 ​cm 2 5×10 or more above / Vs -5 cm 2 / Vs It is a light-emitting device having a maximum value in a degradation curve represented by a change in luminance of light emission obtained when a constant current is passed through the light-emitting device, and is below the following. It is a light-emitting device having a maximum value in a degradation curve represented by a change in luminance of light emission obtained when a constant current is passed through the light-emitting device.

[0015] Alternatively, another aspect of the present invention is a light-emitting device having the above-described configuration, wherein the degradation curve is a light-emitting device having a portion exceeding 100%.

[0016] Alternatively, another aspect of the present invention is an EL layer having an anode, a cathode, and located between the anode and the cathode, wherein the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer, the first layer is in contact with the anode, and the first layer has a first organic compound and a second organic compound, the second layer has a third organic compound, the third layer has a fourth organic compound, the light-emitting layer has a fifth organic compound and a sixth organic compound, the fourth layer has a seventh organic compound, the first organic compound is an organic compound showing electron-accepting property to the second organic compound described above, the fifth organic compound is a light-emitting center substance, the HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, the difference in HOMO level between the third organic compound and the second organic compound is 0. 2 eV or less, the HOMO level of the third organic compound is the same as or deeper than the HOMO level of the second organic compound, and the square root of the electric field strength [V / cm] of the seventh organic compound is 600, and the electron mobility at this time is 1×10 cm / Vs 5×10 or more above cm / Vs -7 cm 2 / Vs 5×10 or more above -5 cm 2 / Vs It is a light-emitting device that is below the following.

[0017] Alternatively, another aspect of the present invention has an anode, a cathode, and an EL layer positioned between the anode and the cathode, and the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer. The first layer is in contact with the anode, and the first layer has a first organic compound and a second organic compound. The second layer has a third organic compound. The third layer has a fourth organic compound. The light-emitting layer has a fifth organic compound and a sixth organic compound. The fourth layer has a seventh organic compound. The first organic compound is an organic compound showing electron-accepting property with respect to the second organic compound described above. The fifth organic compound is a light-emitting central substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less. The HOMO level of the third organic compound is the same as or deeper than the HOMO level of the second organic compound, and the difference in HOMO levels between the third organic compound and the second organic compound is 0.2 eV or less. The LUMO level of the sixth organic compound is shallower than the LUMO level of the seventh organic compound, and the difference in LUMO levels between the seventh organic compound and the sixth organic compound is 0.1 eV or more and 0.3 eV or less. It is a light-emitting device.

[0018] Alternatively, another aspect of the present invention has an anode, a cathode, and an EL layer positioned between the anode and the cathode, and the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer. The first layer is in contact with the anode, and the first layer has a first organic compound and a second organic compound. The second layer has a third organic compound. The third layer has a fourth organic compound. The light-emitting layer has a fifth organic compound and a sixth organic compound. ​​​​​​​​​​​​​ It has an organic compound, the fourth layer has a seventh organic compound, and the first organic compound is the former An organic compound that exhibits electron-accepting properties with respect to the second organic compound described above. The fifth organic compound is a light-emitting Center substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV Or less. The HOMO level of the third organic compound is the same as or deeper than the HOMO Level of the second organic compound, and the difference in HOMO levels between the third organic compound and the second organic compound is 0.2 eV or less. The seventh organic compound is a π-electron-deficient heteroaromatic compound And it is a light-emitting device.

[0019] Alternatively, another aspect of the present invention is an anode, a cathode, and an E located between the anode and the cathode L layer, and the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting Layer, and a fourth layer. The first layer is in contact with the anode, and the first layer has a first Organic compound and a second organic compound. The second layer has a third organic compound. The third layer has a fourth organic compound. The light-emitting layer has a fifth organic compound and a sixth organic Compound. The fourth layer has a seventh organic compound. The first organic compound is the former An organic compound that exhibits electron-accepting properties with respect to the second organic compound described above. The second organic compound has a first Hole-transporting skeleton. The third organic compound has a second hole-transporting skeleton. The former The fourth organic compound has a third hole-transporting skeleton. The fifth organic compound is a light-emitting center Substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less And the first hole-transporting skeleton, the second hole-transporting skeleton, and the third hole-transporting The donor backbone is, independently of each other, any one of a carbazole backbone, a dibenzofuran backbone, a dibenzothiophene backbone and an anthracene backbone, and the electron mobility when the square root of the electric field strength [V / cm] of the seventh organic compound is 600 is 1×10 -7 cm 2 / Vs or more and 5×1 0 -5 cm 2 / Vs or less.

[0020] Alternatively, another aspect of the present invention has an anode, a cathode, and an E L layer located between the anode and the cathode. The EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light emitting layer, and a fourth layer. The first layer is in contact with the anode, and the first layer has a first organic compound and a second organic compound. The second layer has a third organic compound. The third layer has a fourth organic compound. The light emitting layer has a fifth organic compound and a sixth organic compound. The fourth layer has a seventh organic compound. The first organic compound is an organic compound that shows electron accepting properties with respect to the second organic compound. The second organic compound has a first hole transporting backbone. The third organic compound has a second hole transporting backbone. The fourth organic compound has a third hole transporting backbone. The fifth organic compound is a light emitting center substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less The first hole transporting backbone, the second hole transporting backbone, and the third hole transporting backbone are, independently of each other, any one of a carbazole backbone, a dibenzofuran backbone, a dibenzothiophene backbone and an anthracene backbone. The LUMO level of the sixth organic compound is shallower than the LUMO level of the seventh organic compound. The seventh organic compound and the A light-emitting device in which the difference in LUMO levels from an organic compound of 6 is 0.1 eV or more and 0.3 eV or less. is.

[0021] Alternatively, another aspect of the present invention includes an anode, a cathode, and an E located between the anode and the cathode. It has an L layer, and the EL layer has, in order from the anode side, a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer. The first layer is in contact with the anode, and the first layer has a first organic compound and a second organic compound. The second layer has a third organic compound. The third layer has a fourth organic compound. The light-emitting layer has a fifth organic compound and a sixth organic compound. The fourth layer has a seventh organic compound. The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound. The second organic compound has a first hole-transporting skeleton. The third organic compound has a second hole-transporting skeleton. The fourth organic compound has a third hole-transporting skeleton. The fifth organic compound is a light-emitting center substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less. The first hole-transporting skeleton, the second hole-transporting skeleton, and the third hole-transporting skeleton are each independently any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. The seventh organic compound is a π-electron-deficient heteroaromatic compound. It is a light-emitting device. is. The second organic compound has a first hole-transporting skeleton. The third organic compound has a second hole-transporting skeleton. The fourth organic compound has a third hole-transporting skeleton. The fifth organic compound is a light-emitting center substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less. is. The first hole-transporting skeleton, the second hole-transporting skeleton, and the third hole-transporting skeleton are each independently any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. The seventh organic compound is a π-electron-deficient heteroaromatic compound. It is a light-emitting device. is. is.

[0022] Alternatively, another aspect of the present invention is a light-emitting device in which, in the above configuration, the π-electron-deficient heteroaromatic compound is any one of a quinoxaline skeleton, a benzimidazole skeleton, and a triazine skeleton. is.

[0023] Alternatively, in another aspect of the present invention, in the above configuration, the sixth organic compound is a hydrocarbon organic compound composed of, and the HOMO level of the sixth organic compound is deeper than that of the fourth organic compound, and the difference in the HOMO levels between the fourth organic compound and the sixth organic compound is 0.2 eV or more and 0.4 eV or less, which is a light-emitting device.

[0024] Alternatively, in another aspect of the present invention, in the above configuration, the sixth organic compound is anthracene organic compound having a skeleton and a heterocyclic skeleton, and the difference in the HOMO levels between the fourth organic compound and the sixth organic compound is less than 0.2 eV, which is a light-emitting device.

[0025] Alternatively, in another aspect of the present invention, in the above configuration, the sixth organic compound is anthracene organic compound having a skeleton and a heterocyclic skeleton, and the fourth organic compound is an organic compound in which two carbazole rings are bonded to a naphthalene ring which is a light-emitting device.

[0026] Alternatively, in another aspect of the present invention, in the above configuration, the sixth organic compound is anthracene organic compound having a skeleton and a heterocyclic skeleton, and the fourth organic compound is 3,3'-(naphtho thalene-1,4-diyl)bis(9-phenyl-9H-carbazole), which is a light-emitting device .

[0027] Alternatively, in another aspect of the present invention, in the above configuration, the sixth organic compound is anthracene organic compound having a skeleton and a heterocyclic skeleton, and the HOMO level of the second organic compound is -5.4 eV or more and -5.7 eV or less, and the electric field strength of the seventh organic compound [V / cm The electron mobility when the square root of is 600 is lower than the electron mobility of the sixth organic compound at an electric field strength of [V / cm

[0028] Or, another aspect of the present invention is a light-emitting device in which, in the above configuration, the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less

[0029] Or, another aspect of the present invention is a light-emitting device in which, in the above configuration, the HOMO level of the fourth organic compound is deeper than the HOMO level of the third organic compound

[0030] Or, another aspect of the present invention is a light-emitting device in which, in the above configuration, the second organic compound is an organic compound having a dibenzo furan skeleton

[0031] Or, another aspect of the present invention is a light-emitting device in which, in the above configuration, the seventh organic compound is an organic compound having a quinoxaline skeleton

[0032] Or, another aspect of the present invention is a light-emitting device in which, in the above configuration, the second organic compound and the third organic compound are the same substance

[0033] Or, another aspect of the present invention is a light-emitting device in which, in the above configuration, the fifth organic compound is a blue fluorescent material

[0034] Or, another aspect of the present invention is an electronic device having a sensor, an operation button, a speaker, or a microphone

[0035] ​​​​​​​Alternatively, another aspect of the present invention is a light-emitting device having a transistor or a substrate in the above configuration.

[0036] Alternatively, another aspect of the present invention is a lighting device having a housing in the above configuration.

[0037] Note that the light-emitting device in this specification includes an image display device using a light-emitting device. In addition, a module in which a connector, for example, an anisotropic conductive film or a TCP (Tape Carrier Package) is attached to the light-emitting device, a module in which a printed wiring board is provided at the tip of the TCP, or a module in which an IC (integrated circuit) is directly mounted on the light-emitting device by a COG (Chip On Glas s) method may have a light-emitting device. Further, lighting fixtures and the like may have a light-emitting device.

Advantages of the Invention

[0038] In one aspect of the present invention, a novel light-emitting device can be provided. Alternatively, a light-emitting device with good lifespan can be provided. Alternatively, a light-emitting device with good luminous efficiency can be provided.

[0039] Alternatively, in another aspect of the present invention, a highly reliable light-emitting device, electronic device, and display device can be provided respectively. Alternatively, in another aspect of the present invention, a light-emitting device, electronic device, and display device with low power consumption can be provided respectively.

[0040] Note that the description of these effects does not prevent the existence of other effects. Note that one aspect of the present invention does not necessarily have all of these effects. Note that effects other than these , which will naturally become clear from the descriptions in the specification, drawings, claims, etc. The specification, drawings , claims, etc., it is possible to extract other effects from these descriptions.

Brief Description of the Drawings

[0041]

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Embodiments for Carrying Out the Invention

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and those skilled in the art can easily understand that the form and details thereof can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention is not to be construed as being limited to the description of the embodiments shown below.

[0043] (Embodiment 1) Figure 1(A) shows a diagram representing a light-emitting device according to an aspect of the present invention. The light-emitting device according to an aspect of the present invention has an anode 101, a cathode 102, and an EL layer 103, and the EL layer has a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, and an electron transport layer 114.

[0044] In addition, an electron injection layer 115 is shown in the EL layer 103 in FIG. 1(A), but the configuration of the light-emitting device is not limited thereto. As long as it has the above-described configuration, layers having other functions may be included.

[0045] The hole injection layer 111 contains a first organic compound and a second organic compound. The first organic compound is a substance that exhibits electron-accepting properties with respect to the second organic compound. Further, the second organic compound is a substance having a relatively deep HOMO level of -5.7 eV or more and -5.2 eV or less. Since the second organic compound has a relatively deep HOMO level, injection of holes into the hole transport layer 112 becomes easy.

[0046] As the first organic compound, an organic compound having an electron-withdrawing group (particularly a halogen group such as a fluoro group or a cyano group) can be used, and from such substances, a substance that exhibits electron-accepting properties with respect to the second organic compound can be appropriately selected. Examples of such organic compounds include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano- 1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3 ,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-T , and the like. CNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octa fluoro-7H-pyrene-2-ylidene) malononitrile and the like can be mentioned. In particular , compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms, such as HAT-CN, are thermally stable and preferable. Further, [3]radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) are preferable because they have very high electron-accepting properties. Specifically, α,α’,α’’-1,2,3-cyclopropanetriylidene tris 4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α’,α ’’-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-di fluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α’,α’’- 1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluoro benzeneacetonitrile] and the like can be mentioned.

[0047] The second organic compound is preferably an organic compound having hole-transporting properties, and preferably has any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9- fluorenyl group is bonded to the nitrogen of the amine via an arylene group may also be used. When these second organic compounds are substances having an N,N-bis(4-biphenyl)amino group , it is preferable because a light-emitting device having good lifetime can be fabricated . As the second organic compound as described above, specifically, N-(4-biphenyl)-6, a substance having an N,N-bis(4-biphenyl)amino group is preferable because a light-emitting device having good lifetime can be fabricated . Specifically, as the second organic compound as described above, N-(4-biphenyl)-6, N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfA BP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2- d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo [b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1 ,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-bip henyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf( 8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4 -amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran -4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-N-phenyl-4-biphenyl lamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyl triphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]- 4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4-(2;1 '-binaphthyl-6-yl)-4',4''-diphenyltriphenylamine (abbreviation: B BAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl )triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4' '-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB- 03), 4-(6;2'-Binaphthyl-2-yl)-4',4''-diphenyltriphenyl amine (abbreviation: BBA(βN2)B), 4-(2;2'-Binaphthyl-7-yl)- 4',4''-diphenyltriphenylamine (abbreviation: BBA(βN2)B-03), 4 -(1;2'-Binaphthyl-4-yl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNαNB), 4-(1;2'-Binaphthyl-5-yl)-4',4'' -diphenyltriphenylamine (abbreviation: BBAβNαNB-02), 4-(4-Biphe nyl)-4'-(2-Naphthyl)-4''-phenyltriphenylamine (abbreviation: TP BiAβNB), 4-(3-Biphenylyl)-4'-[4-(2-Naphthyl)phenyl] -4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-Bi phenylyl)-4'-[4-(2-Naphthyl)phenyl]-4''-phenyltriphenyl lamine (abbreviation: TPBiAβNBi), 4-(1-Naphthyl)-4'-phenyltrip henylamine (abbreviation: αNBA1BP), 4,4'-Bis(1-Naphthyl)triphenyl amine (abbreviation: αNBB1BP), 4,4'-Diphenyl-4''-[4'-(Carbaz ol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP ), 4'-[4-(3-Phenyl-9H-carbazol-9-yl)phenyl]tris( 1,1'-Biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4 '-(Carbazol-9-yl)biphenyl-4-yl]-4'-(2-Naphthyl)-4 ''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-Phe nyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-Naphthyl)phenyl Ru]-9,9'-Spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF) , N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobi[9H- fluorene]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl yl]-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BB ASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl- 9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-f luorene-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-( 1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl yl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9 -phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-p henyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mB PAFLP), 4-phenyl-4'-[4-(9-phenylfluorene-9-yl)phenyl yl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phe nyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)tri phenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phe nyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4 ,4'-bis(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl )triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl -9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene -amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)- 9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl yl]-9H-fluorene-2-amine (abbreviation: PCBBiF), etc. can be mentioned.

[0048] The hole transport layer 112 has a first hole transport layer 112-1 and a second hole transport layer 112-2. The first hole transport layer 112-1 is positioned closer to the anode 101 side than the second hole transport layer 112-2. Note that the second hole transport layer 112-2 may also simultaneously function as an electron blocking layer.

[0049] The first hole transport layer 112-1 contains a third organic compound, and the second hole transport layer 112-2 contains a fourth organic compound.

[0050] The third organic compound and the fourth organic compound are preferably organic compounds having hole transporting properties. The third organic compound and the fourth organic compound can be the same organic compounds that can be used as the above-mentioned second organic compound.

[0051] Regarding the HOMO levels of the second organic compound and the third organic compound, it is preferable to select the materials such that the HOMO level of the third organic compound is deeper and the difference is 0.2 eV or less. Note that the second organic compound and the third organic compound can be the same substance. Even more preferable. Further, in the HOMO level of the third organic compound and the HOM O level of the fourth organic compound, it is preferable that the HOMO level of the fourth organic compound is deeper. Furthermore, the materials may be selected such that the difference is 0.2 eV or less. By the HOMO levels of the second to fourth organic compounds being in the above relationship, holes can be smoothly injected into each layer, preventing an increase in the driving voltage and a shortage of holes in the light-emitting layer.

[0052] Note that the second to fourth organic compounds preferably each have a hole-transporting skeleton. As the hole-transporting skeleton, a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton that do not cause the HOMO levels of these organic compounds to become too shallow are preferable. Further, it is preferable that these hole-transporting skeletons are common to the materials of adjacent layers (for example, the second organic compound and the third organic compound or the third organic compound and the fourth organic compound), as this enables smooth hole injection. In particular, as these hole-transporting skeletons, a dibenzofuran skeleton is preferable.

[0053] Moreover, it is a preferable configuration that the materials contained in adjacent layers (for example, the second organic compound and the third organic compound or the third organic compound and the fourth organic compound) are the same material, as this enables even smoother hole injection. In particular, a configuration where the second organic compound and the third organic compound are the same material is preferable.

[0054] The light-emitting layer 113 has a fifth organic compound and a sixth organic compound. The fifth organic compound is a light-emitting center substance, and the sixth organic compound is a host material for dispersing the fifth organic compound.

[0055] The light-emitting center material may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or any other light-emitting material. Also, it may be a single layer or may be composed of a plurality of layers containing different light-emitting materials. Note that one aspect of the present invention is that the light-emitting layer 113 is a layer exhibiting fluorescence emission, particularly a layer exhibiting blue fluorescence emission and can be preferably applied in some cases.

[0056] In the light-emitting layer 113, examples of materials that can be used as the fluorescent substance include, for example, the following substances. Also, other fluorescent substances can be used.

[0057] 5,6-Bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-Bis[4'-(10-phenyl-9-anthryl biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N, N'-Diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl )phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bi s(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren- 9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn ), N,N'-Bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-di phenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol -9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol -9-yl)-4'-(9,10-diphenyl Nil-2-antryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl Nil-N-[4-(10-phenyl-9-antryl)phenyl]-9H-carbazole -3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra(tert- butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-antryl)-4’- (9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA PA), N,N’’-(2-tert-butylanthracene-9,10-diyl-di-4, 1-phenylene)bis[N,N’,N’-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2 -antryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA) 、N-[4-(9,10-diphenyl-2-antryl)phenyl]-N,N’,N’- triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N’, N’,N’’,N’’,N’’’,N’’’-octaphenyldibenzog,p]chryse ne-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9, 10-diphenyl-2-antryl)-N,9-diphenyl-9H-carbazole-3- amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1’-biphenyl-2-yl )-2-antryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation : 2PCABPhA), N-(9,10-diphenyl-2-antryl)-N,N’,N ’-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,1 0-Bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-tri phenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis (1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phen enyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N ,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), coumarin 54 5T, N,N'-diphenylquinacridone, (abbreviation: DPQd), rubrene, 5,12- bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: B PT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl -4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-meth thyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoli dine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation : DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5 ,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N '-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3, 10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1 ,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[i j]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinit rile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7 -tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizid {-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl} -4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{ 2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7- tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H- pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N’-( pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N -(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2 ,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)- 02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho [2,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,10FrA2Nbf( IV)-02), etc. are mentioned. In particular, condensed aromatic diamine compounds typified by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLP APrn, and 1,6BnfAPrn-03 have high hole trap properties and are excellent in luminescence efficiency and reliability, so they are preferable.

[0058] When a phosphorescent material is used as the light-emitting center material in the light-emitting layer 113, examples of the possible materials include the following.

[0059] ​Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H -1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III )(abbreviation: Ir(mpptz-dmp)3), tris(5-methyl-3,4-diphenyl -4H-1,2,4-triazolato)iridium(III)(abbreviation: Ir(Mptz)3 ), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2 ,4-triazolato]iridium(III)(abbreviation: Ir(iPrptz-3b)3) of such organometallic iridium complexes having a 4H-triazole skeleton, and tris[3-methyl -1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iri dium(III)(abbreviation: Ir(Mptz1-mp)3), tris(1-methyl-5-f enyl-3-propyl-1H-1,2,4-triazolato)iridium(III)(abbreviation : Ir(Prptz1-Me)3) of such organometallic iri dium complexes having a 1H-triazole skeleton, and fac-tris[1-(2,6-diisopropylphenyl)-2-phen yl-1H-imidazole]iridium(III)(abbreviation: Ir(iPrpmi)3), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phena ntridinato]iridium(III)(abbreviation: Ir(dmpimpt-Me)3) of such imidazole skeleton-containing organometallic iridium complexes, and bis[2-(4’,6’-dif luorophenyl)pyridinato-N,C 2’ iridium(III) tetrakis(1-pyra zolyl)borate(abbreviation: FIr6), bis[2-(4’,6’-difluorophenyl) pyridinato-N,C 2’Iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3’,5’-bis(trifluoromethyl)phenyl]pyridinato-N,C 2 ’}iridium(III) picolinate (abbreviation: Ir(CF3ppy)2(pic)), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium( III) acetylacetonate (abbreviation: FIr(acac)) and other phenylpyridine derivatives having an electron-withdrawing group are mentioned. These are compounds that exhibit blue phosphorescent emission and have an emission peak from 440 nm to 520 nm.

[0060] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)3), tris(4-t-butyl-6-phenylpyrimidinato)iridium (III) (abbreviation: Ir(tBuppm)3), (acetylacetonato)bis(6-meth yl-4-phenylpyrimidinato)iridium(III) (abbreviation: Ir(mppm)2( acac)), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrim idinato)iridium(III) (abbreviation: Ir(tBuppm)2(acac)), (a cetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iri dium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacet onato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]i ridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacet ​​Sodium bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: Ir(d ppm)2(acac)), organometallic iridium complexes having a pyrimidine skeleton, and (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium (III) (abbreviation: Ir(mppr-Me)2(acac)), (acetylacetonato) bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: Ir(mppr-iPr)2(acac)), organometallic iridium complexes having a pyrazine skeleton, and tris(2-phenylpyridinato-N,C 2’ )iridium(I II) (abbreviation: Ir(ppy)3), bis(2-phenylpyridinato-N,C 2’ )ir dium(III) acetylacetonate (abbreviation: Ir(ppy)2acac), bis(be nzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: Ir(bz q)2(acac)), tris(benzo[h]quinolinato)iridium(III) (abbreviation : Ir(bzq)3), tris(2-phenylquinolinato-N,C 2’ )iridium(I II) (abbreviation: Ir(pq)3), bis(2-phenylquinolinato-N,C 2’ )ir dium(III) acetylacetonate (abbreviation: Ir(pq)2(acac)), organometallic iridium complexes having a pi ridine skeleton, and tris(acetylacetonato)(mono phenanthroline)terbium(III) (abbreviation: Tb(acac)3(Phen)) and other rare earth metal complexes. These are mainly compounds that exhibit green phosphorescent emission and have an emission peak at 500 nm to 600 nm. In addition, organic compounds having a pyrimidine skeleton The metal iridium complex is particularly preferred because it is outstanding in terms of reliability and luminous efficiency.

[0061] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidi inato]iridium(III) (abbreviation: Ir(5mdppm)2(dibm)), bis[4 ,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium (III) (abbreviation: Ir(5mdppm)2(dpm)), bis[4,6-di(naphthalen -1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: Ir(d1npm)2(dpm)) and other organometallic iridium complexes having a pyrimidine skeleton, (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridi um(III) (abbreviation: Ir(tppr)2(acac)), bis(2,3,5-triphe nylpyrrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: Ir(tpp r)2(dpm)), (acetylacetonato)bis[2,3-bis(4-fluoropheny l)quinoxalinato]iridium(III) (abbreviation: Ir(Fdpq)2(acac)) and other organometallic iridium complexes having a pyrazine skeleton, tris(1-phenylisoqui nolinato-N,C 2’ )iridium(III) (abbreviation: Ir(piq)3), bis(1- phenylisoquinolinato-N,C 2’ )iridium(III) acetylacetonate (abbre viation: Ir(piq)2acac) and other organometallic iridium complexes having a pyridine skeleton In addition, platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-por phyrin platinum(II) (abbreviation: PtOEP), and tris(1,3-dif Europium(III) tris(1-phenyl-1,3-propanedionato)(monophenanthroline) (Abbreviation: Eu(DBM)3(Phen)), tris[1-(2-thenoyl)-3,3,3 -trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: Eu(TTA)3(Phen)), and other rare earth metal complexes. These are compounds that exhibit red phosphorescent emission and have an emission peak in the range of 600 nm to 700 nm. In addition, organometallic iridium complexes having a pyrazine skeleton can obtain red emission with good chromaticity .

[0062] In addition to the phosphorescent compounds described above, known phosphorescent emission materials can also be selected and used .

[0063] As TADF materials, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc. can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (P d), etc. can be mentioned. Examples of the metal-containing porphyrins include protoporphyrin-tin fluoride complex (SnF2(Pro to IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporph hyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4M e)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporph hyrin-tin fluoride complex (SnF2(Etio I)), octaethylporphyrin - Platinum chloride complex (PtCl2OEP) etc. can also be mentioned.

[0064]

Chem.

[0065] Also, 2-(biphenyl-4-yl)-4,6-bis(12-f enylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine( Abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2- yl)-9’-phenyl-9H,9’H-3,3’-bicarbazole (abbreviation: PCCzT zn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-c arbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbre viation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl -4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4 -(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5- diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-di methyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACR XTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl] sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10’H-spiro[a cridine-9,9’-anthracene]-10’-one (abbreviation: ACRSA), etc. of π-electron excess type heteroaromatic ring and one or both of π-electron deficient type heteroaromatic rings can also be used. The heteroaromatic ring compound has a π-electron excess type heteroaromatic ring and a π-electron deficient type heteroaromatic ring. Since it has a fragrant ring, it is preferable that both the electron transporting property and the hole transporting property are high. Among them, the π-electron skeleton having a deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, py razine skeleton, pyridazine skeleton), and the triazine skeleton are preferable because they are stable and have good reliability. In particular, the benzofuropyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuropy razine skeleton, and the benzothienopyrazine skeleton are preferable because they have high electron accepting properties and good reliability. Among the skeletons having a π-electron excessive heteroaromatic ring, the acridine skeleton, the phenoxa zine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton, and the pyrrole skeleton are stable and have good reliability, so it is preferable to have at least one of these skeletons. Note that as the furan skeleton, the dibenzofuran skeleton is preferable, and as the thiophene skeleton, the dibenzothiophene skeleton is preferable. As the pyrrole skeleton, the indole skeleton, the carbazole skeleton, the indolocarbazole skeleton, the bicarbaazole skeleton, and the 3-(9-phenyl-9H-carb azole-3-yl)-9H-carbazole skeleton are particularly preferable. Note that a substance in which a π-electron excessive heteroaromatic ring and a π-electron deficient heteroaromatic ring are directly bonded has both strong electron donating properties of the π-electron excessive heteroaromatic ring and strong electron accepting properties of the π-electron deficient heteroaromatic ring, and the energy difference between the S1 level and the T1 level becomes small, so it is particularly preferable because thermally activated delayed fluorescence can be efficiently obtained. Note that instead of the π-electron deficient heteroaromatic ring, an aromatic ring to which an electron withdrawing group such as a cyano group is bonded may be used. Further, as the π-electron excessive skeleton, an aromatic amine skeleton, a phena zine skeleton, etc. can be used. Further, as the π-electron deficient skeleton, a xanthene skeleton, a thio skeleton, etc. can be used. Further, as the π-electron deficient skeleton, a xanthene skeleton, a thio An oxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazo le skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or borantrene, benzo nitrile or an aromatic ring or heteroaromatic ring having a nitrile group or cyano group such as cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. can be used. Thus, a π-electron-deficient skeleton and a π-electron-excessive skeleton can be used instead of at least one of the π-electron-deficient heteroaromatic ring and the π-electron-excessive heteroaromatic ring.

[0066]

Chemical formula

[0067] Note that a TADF material is a material having a small difference between the S1 level and the T1 level and capable of converting energy from the triplet excitation energy to the singlet excitation energy by reverse intersystem crossing. Therefore, the triplet excitation energy can be up-converted (reverse intersystem crossing) to the singlet excitation energy by a small amount of thermal energy, and the singlet excited state can be efficiently generated. Also, the triplet excitation energy can be converted into light.

[0068] Also, an exciplex (also called an exciplex or an Exciplex) that forms an excited state with two substances has a very small difference between the S1 level and the T1 level and has a function as a TADF material capable of converting triplet excitation energy into singlet excitation energy.

[0069] ​​​​​​​​​​​As an index of the T1 level, a phosphorescence spectrum observed at a low temperature (for example, from 77K to 10K) may be used. As for the TADF material, a tangent is drawn at the trailing edge on the short-wavelength side of its fluorescence spectrum, and the energy of the wavelength of the extrapolated line is defined as the S1 level. When a tangent is drawn at the trailing edge on the short-wavelength side of the phosphorescence spectrum and the energy of the wavelength of the extrapolated line is defined as the T1 level, it is preferable that the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less. When using the TADF material as the light-emitting center material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material. For the host material of the light-emitting layer, various carrier transport materials such as materials having electron transport properties, materials having hole transport properties, and TADF materials can be used. Examples of the material having hole transport properties include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluorene-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-

[0070]

[0071]

[0072] ​​​​​​​​​​​​​​phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine ( Abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazone PCBBi1BP, 4-(1-naphthalene-3-yl)triphenylamine ethyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine ( Abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H -Carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl 4-(9-phenyl-9H-carbazol-3-yl)phenyl N-phenyl-N-[4-(9- Phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fu Compounds with an aromatic amine skeleton, such as PCBASF 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N- Carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl) 3,3'-bis(9-phenyl- 9H-carbazole (abbreviation: PCCP) and other compounds with a carbazole skeleton, ,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)(abbreviation Name: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-ful oren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4 -[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzyl Compounds with a thiophene skeleton, such as dibenzothiophene (abbreviation: DBTFLP-IV), 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation : DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl )phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), etc. Compounds having a flu ne skeleton are exemplified. Among those described above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transportability, and contribute to a reduction in driving voltage. Further, the organic compounds exemplified as the above-described second organic compound can also be used.

[0073] Examples of the material having electron transport properties include, for example, bis(10-hydroxybenzo[h]quinoli nato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato )(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8- quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl) phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl) phenolato]zinc(II) (abbreviation: ZnBTZ), etc. metal complexes, and 2-(4-bipheny ryl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation : PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylph enyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-te rt-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl) Phenyl]-9H-carbazole (abbreviation: CO11), 2,2’,2’’-(1,3,5 -benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TP BI), 2-[3-(Dibenzothiophen-4-yl)phenyl]-1-phenyl-1H -benzimidazole (abbreviation: mDBTBIm-II), etc., heterocyclic compounds having a polyazole skeleton, and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f ,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(dibenzothio phen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2 mDBTBPDBq-II), 2-[3’-(9H-carbazol-9-yl)biphenyl -3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6 -bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPn P2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation : 4,6mDBTP2Pm-II), etc., heterocyclic compounds having a diazine skeleton, and 3,5 -bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCz PPy), 1,3,5-tri[3-(3-pyridyl)-phenyl]benzene (abbreviation: Tm PyPB), etc., heterocyclic compounds having a pyridine skeleton. Among the above, heterocyclic compounds having a dia zine skeleton and heterocyclic compounds having a pyridine skeleton have good reliability and are preferable. In particular, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties and contribute to reducing the driving voltage.

[0074] The TADF materials that can be used as host materials are the same as those listed above. When a TADF material is used as a host material, the The triplet excitation energy is converted to singlet excitation energy by reverse intersystem crossing, and The luminous efficiency of the light-emitting element can be improved by transferring energy to the luminescent center substance. In this case, the TADF material acts as an energy donor, and the luminescent center acts as an energy absorber. It functions as a receptor.

[0075] This is extremely effective when the luminescent center substance is a fluorescent substance. In order to obtain high luminous efficiency, the S1 level of the TADF material must be higher than the S1 level of the fluorescent material. The T1 level of the TADF material is preferably higher than the S1 level of the fluorescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent material. It is preferable that the level is higher.

[0076] In addition, T that emits light that overlaps with the lowest energy absorption band of the fluorescent material It is preferable to use ADF materials. This allows the TADF material to be converted into a fluorescent material. This is preferable because the transfer of excitation energy becomes smooth and light emission can be obtained efficiently.

[0077] In addition, singlet excitation energy is efficiently generated from triplet excitation energy by reverse intersystem crossing. In order for this to happen, it is preferable for carrier recombination to occur in the TADF material. The triplet excitation energy generated in the DF material is transferred to the triplet excitation energy of the fluorescent material. For this purpose, it is preferable that the fluorescent substance has a luminophore ( It is preferable to have a protecting group around the skeleton that causes luminescence). As the protecting group, a substituent having no π bond is preferable, a saturated hydrocarbon is preferable, specifically, an alkyl group having 3 or more and 10 or less carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 or more and 10 or less carbon atoms, and a trialkylsilyl group having 3 or more and 10 or less carbon atoms are mentioned. It is more preferable to have a plurality of protecting groups. Since a substituent having no π bond has poor function of transporting carriers, it can keep the distance between the TADF material and the lumophore of the fluorescent substance far without hardly affecting carrier transport and carrier recombination. Here, the lumophore refers to an atomic group (skeleton) that causes luminescence in the fluorescent substance. The lumophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, etc. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton are preferable because of their high fluorescence quantum yields. A substituent having no π bond is preferable, a saturated hydrocarbon is preferable, specifically, an alkyl group having 3 or more and 10 or less carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 or more and 10 or less carbon atoms, and a trialkylsilyl group having 3 or more and 10 or less carbon atoms are mentioned. It is more preferable to have a plurality of protecting groups. Since a substituent having no π bond has poor function of transporting carriers, it can keep the distance between the TADF material and the lumophore of the fluorescent substance far without hardly affecting carrier transport and carrier recombination. Here, the lumophore refers to an atomic group (skeleton) that causes luminescence in the fluorescent substance. The lumophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, etc. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton are preferable because of their high fluorescence quantum yields. When using a fluorescent substance as a luminescent center substance, as the host material, a material having an anthracene skeleton is suitable. When using a substance having an anthracene skeleton as the host material of the fluorescent substance, it is possible to realize a light-emitting layer with good luminous efficiency and durability. Examples of the substance having an anthracene skeleton used as the host material include diphenylanthracene skeleton Here, the lumophore refers to an atomic group (skeleton) that causes luminescence in the fluorescent substance. The lumophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, etc. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton are preferable because of their high fluorescence quantum yields. When using a fluorescent substance as a luminescent center substance, as the host material, a material having an anthracene skeleton is suitable. When using a substance having an anthracene skeleton as the host material of the fluorescent substance, it is possible to realize a light-emitting layer with good luminous efficiency and durability. Examples of the substance having an anthracene skeleton used as the host material include diphenylanthracene skeleton Here, the lumophore refers to an atomic group (skeleton) that causes luminescence in the fluorescent substance. The lumophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the condensed aromatic ring or the condensed heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, etc. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton are preferable because of their high fluorescence quantum yields. When using a fluorescent substance as a luminescent center substance, as the host material, a material having an anthracene skeleton is suitable. When using a substance having an anthracene skeleton as the host material of the fluorescent substance, it is possible to realize a light-emitting layer with good luminous efficiency and durability.

[0078] When using a fluorescent substance as a luminescent center substance, as the host material, a material having an anthracene skeleton is suitable. When using a substance having an anthracene skeleton as the host material of the fluorescent substance, it is possible to realize a light-emitting layer with good luminous efficiency and durability. Examples of the substance having an anthracene skeleton used as the host material include diphenylanthracene skeleton When using a fluorescent substance as a luminescent center substance, as the host material, a material having an anthracene skeleton is suitable. When using a substance having an anthracene skeleton as the host material of the fluorescent substance, it is possible to realize a light-emitting layer with good luminous efficiency and durability. Examples of the substance having an anthracene skeleton used as the host material include diphenylanthracene skeleton Substances having a lattice, particularly a 9,10-diphenylanthracene skeleton, are chemically stable. Therefore, they are preferable. When the host material has a carbazole skeleton, it is preferable because of its high hole injection and transport properties. However, when the carbazole ring further condenses with a benzene ring to form a benzocarbazole skeleton, the HOMO becomes about 0.1 eV shallower than that of carbazole, making it easier for holes to enter. Therefore, it is even more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, the HOMO becomes about 0.1 eV shallower than that of carbazole, making it easier for holes to enter. Moreover, it has excellent hole transport properties and high heat resistance, so it is suitable. Therefore, more preferably as the host material is a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). From the above perspective of hole injection and transport properties, instead of the carbazole skeleton, a benzofluorene skeleton or a dibenzofluorene skeleton may be used. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9 H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl -9-anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgD BCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo [b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10 -{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene ​ Tracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl) phenyl]anthracene (abbreviation: αN-βNPAnth), etc. can be mentioned. In particular, CzP A, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good characteristics, so they are preferred choices.

[0079] Note that the host material may be a material obtained by mixing multiple substances. When using the mixed host material, it is preferable to mix a material having electron transporting properties and a material having hole transporting properties. By mixing a material having electron transporting properties and a material having hole transporting properties, the transport properties of the light emitting layer 113 can be easily adjusted, and the control of the recombination region can also be easily performed. The weight ratio of the content of the material having hole transporting properties to the material having electron transporting properties may be hole transporting material: electron transporting material = 1:19 to 19:1.

[0080] Note that, as part of the above mixed material, a phosphorescent substance can be used. The phosphorescent substance can be used as an energy donor that supplies excitation energy to the fluorescent substance when using the fluorescent substance as the light emitting center material.

[0081] In addition, an exciplex may be formed between these mixed materials. By selecting a combination that forms an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the light emitting material, energy transfer becomes smooth and efficient light emission can be obtained, which is preferable. Also, since the driving voltage is reduced by using this configuration, it is preferable.

[0082] Note that at least one of the materials forming the exciplex may be a phosphorescent material. By doing so, triplet excitation energy can be efficiently converted to singlet excitation energy by reverse intersystem crossing.

[0083] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transporting properties is higher than the HOMO level of the material having electron transporting properties. Also, it is preferable that the LUMO level of the material having hole transporting properties is higher than the LUMO level of the material having electron transporting properties. Note that the LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV).

[0084] Note that the formation of the exciplex can be confirmed, for example, by comparing the emission spectra of the material having hole transporting properties, the emission spectra of the material having electron transporting properties, and the emission spectra of the mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film is shifted to a longer wavelength (or has a new peak on the longer wavelength side) than the emission spectra of the respective materials. Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of the material having hole transporting properties, the transient PL of the material having electron transporting properties, and the transient PL of the mixed film obtained by mixing these materials, and observing the difference in transient response such that the transient PL lifetime of the mixed film has a longer lifetime component or the ratio of the delayed component becomes larger than the transient PL lifetimes of the respective materials. Also, the above-mentioned transient PL may be read as transient electroluminescence (EL). That is, the transient EL of the material having hole transporting properties, the transient E By comparing the transient EL of L and these mixed films and observing the differences in transient responses, the formation of the exciplex can also be confirmed.

[0085] Here, when the sixth organic compound is composed only of hydrocarbons such as the above αN-βNPAnth, in terms of the HOMO level of the fourth organic compound and the HOM O level of the sixth organic compound, the HOMO level of the sixth organic compound is deeper, and the difference is preferably 0.2 eV or more and 0.4 eV or less because the hole transportability is moderately hindered by the barrier.

[0086] Also, when the sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton such as the above cgDBCzPA or CzPA, the difference in the HOMO levels between the fourth organic compound and the sixth organic compound is preferably less than 0.2 eV because holes can be injected without being hindered by the injection barrier. In this case, in particular, the fourth organic compound is preferably an organic compound in which two carbazole rings are bonded to a naphthalene ring, and typically, 3,3'-(naph thalene-1,4-diyl)bis(9-phenyl-9H-carbazole) can be mentioned. be mentioned.

[0087] Also, when the sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton such as the above cgDBCzPA or CzPA, the HOMO level of the second organic compound is preferably -5. 4 eV or more and -5.7 eV or less because deterioration is more suppressed.

[0088] The electron transport layer 114 has a seventh organic compound. The seventh organic compound is an organic compound having electron transport properties, and is preferably a π-electron-deficient heteroaromatic compound. Note that ​​​In particular, it preferably has a skeleton of any one of a quinoxaline skeleton, a benzimidazole skeleton, and a triazine skeleton. As the organic compound having electron transporting properties, an organic compound having electron transporting properties that can be used for the above host material, or an organic compound listed as an organic compound that can be used as a host material for the above fluorescent light-emitting substance can be used. Further, the seventh organic compound preferably has an electron mobility of 1×10 cm / Vs or more and 5×10

[0089] cm -7 cm 2 / Vs or less. When comparing the LUMO level of the sixth organic compound with the LUMO level of the seventh organic compound, it is preferable that the LUMO level of the sixth organic compound is shallower, and more preferably, the difference is 0.1 eV or more and 0.3 eV or less. -5 cm 2 / Vs or less. Further, when the square root of the electric field strength [V / cm] of the seventh organic compound is 600, the electron mobility is smaller than the electron mobility when the square root of the electric field strength [V / cm] of the sixth organic compound is 600. In the former case, by reducing the electron transportability in the electron transport layer, and in the latter case, by controlling the amount of electrons injected into the light-emitting layer due to the difference in the LUMO level, it is possible to prevent the light-emitting layer from being in a state of excessive electrons. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. Furthermore, when the square root of the electric field strength [V / cm] of the seventh organic compound is 600, the electron mobility is preferably smaller than the electron mobility when the square root of the electric field strength [V / cm] of the sixth organic compound is 600. In the former case, by reducing the electron transportability in the electron transport layer, and in the latter case, by controlling the amount of electrons injected into the light-emitting layer due to the difference in the LUMO level, it is possible to prevent the light-emitting layer from being in a state of excessive electrons. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency.

[0090] When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. When the light-emitting layer is in a state of excessive electrons, the light-emitting region is partially limited, resulting in an increase in the load of the relevant part and an acceleration of deterioration. Also, the light-emitting efficiency decreases because electrons pass through the light-emitting layer without being able to recombine. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency. In one aspect of the present invention, it is possible to prevent such a state and provide a light-emitting device with a long lifespan and good light-emitting efficiency.

[0091] In the light-emitting device having such a configuration, a driving test is performed under the condition of a constant current density. In the luminance degradation curve obtained by the test, after initially degrading slightly from 100%, it shows a degradation behavior of " rising slightly and then degrading again". The light-emitting device of one aspect of the present invention showing such behavior, i.e., a light-emitting device having a maximum value in the degradation curve, becomes a light-emitting device with very good durability. When the differential of such a degradation curve is taken, since there is a portion where the value is 0, in other words, a light-emitting device of one aspect of the present invention having a portion where the differential of the degradation curve becomes 0 can be a light-emitting device with very good durability.

[0092] A light-emitting device of one aspect of the present invention having the above configuration can be a light-emitting device with good durability.

[0093] (Embodiment 2) Subsequently, the detailed structure and examples of materials of the above-described light-emitting device will be described. One aspect of the light-emitting device of the present invention has an EL layer 103 formed of a plurality of layers between a pair of electrodes, an anode 101 and a cathode 102, as described above. The EL layer 103 includes, from the anode 101 side, a hole injection layer 111, a first hole transport layer 112-1, a second hole transport layer 112-2, a light-emitting layer 113, and an electron transport layer 114.

[0094] There are no particular limitations on the other layers included in the EL layer 103, and various layer structures such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a carrier blocking layer, an exciton blocking layer, and a charge generation layer can be applied.

[0095] The anode 101 is a metal, alloy, or conductive compound having a large work function (specifically, 4.0 eV or more). It is preferably formed using substances, and their mixtures, etc. Specifically, for example, indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, indium containing tungsten and zinc oxide (IWZO), etc. are mentioned. These conductive metal oxide films are usually formed by sputtering, but a sol-gel method or the like may be applied for production. As an example of the production method, indium zinc oxide is formed by a sputtering method using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. There is also a method such as this. Further, indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by a sputtering method using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. In addition, gold (Au), platinum (Pt), nickel (Ni), tantalum sten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co) copper (Cu), palladium (Pd), or nitrides of metal materials (for example, titanium nitride), etc. are mentioned. Graphene can also be used. Here, typical substances as materials for forming the anode having a large work function are listed, but in one aspect of the present invention, in the hole injection layer 1 11, a composite material containing an organic compound having hole transporting properties and a substance showing electron accepting properties with respect to the organic compound is used, so an electrode material can be selected

[0096] Regarding the laminated structure of the EL layer 103, in the present embodiment, as shown in FIG. 1(A), holes Injection layer 111, first hole transport layer 112-1, second hole transport layer 112-2, light emitting layer 11 3. A structure having an electron injection layer 115 in addition to the electron transport layer 114, and as shown in FIG. As shown in FIG. 1, the hole injection layer 111, the first hole transport layer 112-1, the second hole transport layer 112-2, Two types of structures are available: a structure having a light-emitting layer 113, an electron transport layer 114, and a charge generation layer 116. The materials constituting each layer are specifically described below.

[0097] Hole injection layer 111, hole transport layer 112 (hole transport layer 112-1, hole transport layer 112-2) Since the light-emitting layer 113 and the electron transport layer 114 have been described in detail in the first embodiment, The corresponding description is omitted. Please refer to the description in the first embodiment.

[0098] Between the electron transport layer 114 and the cathode 102, lithium fluoride (LiF2O3) is provided as the electron injection layer 115. Alkali such as iF, cesium fluoride (CsF), calcium fluoride (CaF2), etc. A layer containing a metal or an alkaline earth metal or a compound thereof may be provided. 5 is a layer made of a substance having an electron transporting property, in which an alkali metal or an alkaline earth metal or It is also possible to use a material containing these compounds or an electride. For example, a material in which electrons are highly added to a mixed oxide of calcium and aluminum is Some examples include:

[0099] In addition, a charge generating layer 1 is formed between the electron transport layer 114 and the cathode 102 instead of the electron injection layer 115. The charge generating layer 116 can be generated by applying a potential. A layer capable of injecting holes into a layer in contact with the cathode side of the layer and electrons into a layer in contact with the anode side of the layer. The charge generating layer 116 includes at least a P-type layer 117. The above-mentioned composite material may be used to form the hole injection layer 111. It is preferable that the P-type layer 117 is formed of the above-mentioned material constituting the composite material. The layer may be formed by laminating a film containing a substance exhibiting electron accepting properties and a film containing a hole transporting material. By applying a potential to the mold layer 117, electrons are transported to the electron transport layer 114, which is the cathode. Holes are injected into 02, causing the light-emitting device to operate.

[0100] In addition to the P-type layer 117, the charge generating layer 116 also includes an electron relay layer 118 and an electron injection buffer layer 119. Preferably, one or both of layers 119 are provided.

[0101] The electron relay layer 118 contains at least a substance having an electron transport property, and the electron injection buffer layer 1 The function of the junction is to prevent the interaction between the P-type layer 117 and the P-type layer 119 and to transfer electrons smoothly. The LUMO level of the substance having electron transport properties contained in the relay layer 118 is The LUMO level of the electron-accepting substance in the electron transport layer 114 is in contact with the charge generating layer 116. It is preferable that the LUMO level of the electron relay layer 118 is between the LUMO level of the material contained in the layer. The specific energy level of the LUMO level in the electron transport material used in The potential is set to -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. The electron relay layer 118 may be made of a phthalocyanine-based material having electron transport properties. It is preferred to use a metal complex having a metal-oxygen bond and an aromatic ligand.

[0102] The electron injection buffer layer 119 may include an element selected from the group consisting of alkali metals, alkaline earth metals, rare earth metals, and These compounds (alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or compounds of rare earth metals (including oxides, halides, carbonates), etc.) with high electron injection properties can be used. Alkaline earth metal compounds (including oxides, halides, carbonates), or compounds of rare earth metals (including oxides, halides, carbonates)) and the like can be used.

[0103] In addition, when the electron injection buffer layer 119 is formed by including a substance having electron transporting properties and an electron donating substance, as the electron donating substance, alkali metals, alkaline earth metals, rare earth metals, and their compounds (alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or compounds of rare earth metals (including oxides, halides, carbonates)), in addition to organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, and decamethylnickelocene can also be used. Note that as the substance having electron transporting properties, a material similar to the material constituting the electron transport layer 114 described above can be used for formation.

[0104] As the material for forming the cathode 102, metals, alloys, electrically conductive compounds, and mixtures thereof having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs), and elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these (MgAg, AlL) ​​​​​i), europium (Eu), ytterbium (Yb), and other rare earth metals, and However, an electron injection layer is provided between the cathode 102 and the electron transport layer. By providing this, regardless of the magnitude of the work function, Al, Ag, ITO, silicon or oxide can be used. Various conductive materials such as indium oxide-tin oxide containing silicon dioxide can be used as the cathode 102. There can be. These conductive materials can be applied by dry methods such as vacuum deposition and sputtering, inkjet printing, It is possible to form the film by using a spin coating method, etc. Also, it is possible to form the film by using a wet sol-gel method. Alternatively, the metal material may be used in a wet process to form the metal layer.

[0105] The EL layer 103 can be formed by a variety of methods, including dry and wet methods. For example, vacuum deposition, gravure printing, offset printing, screen printing, etc. A printing method, an ink jet method, a spin coating method or the like may also be used.

[0106] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0107] The configuration of the layers provided between the anode 101 and the cathode 102 is not limited to the above. However, the proximity of the light-emitting region to the metals used in the electrodes and carrier injection layer In order to suppress the quenching caused by the hole, the hole is located at a position away from the anode 101 and the cathode 102. It is preferable that the phosphorus be provided with a light-emitting region in which the phosphorus and the electron recombine.

[0108] In addition, recombination in the hole transport layer or electron transport layer in contact with the light emitting layer 113, particularly in the light emitting layer 113 The carrier transport layer close to the region suppresses the energy transfer from excitons generated in the light-emitting layer. Therefore, it is preferable that the material is composed of a substance having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer. Preferably, it is composed of a substance having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer. Preferably.

[0109] Subsequently, with reference to FIG. 1(C), an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are stacked (also referred to as a stacked element or a tandem element) will be described. This light-emitting device is a light-emitting device having a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has substantially the same structure as the EL layer 103 shown in FIG. 1(A). That is, the light-emitting device shown in FIG. 1(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) or FIG. 1(B) can be said to be a light-emitting device having one light-emitting unit. Subsequently, with reference to FIG. 1(C), an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are stacked (also referred to as a stacked element or a tandem element) will be described. This light-emitting device is a light-emitting device having a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has substantially the same structure as the EL layer 103 shown in FIG. 1(A). That is, the light-emitting device shown in FIG. 1(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) or FIG. 1(B) can be said to be a light-emitting device having one light-emitting unit. Subsequently, with reference to FIG. 1(C), an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are stacked (also referred to as a stacked element or a tandem element) will be described. This light-emitting device is a light-emitting device having a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has substantially the same structure as the EL layer 103 shown in FIG. 1(A). That is, the light-emitting device shown in FIG. 1(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) or FIG. 1(B) can be said to be a light-emitting device having one light-emitting unit. That is, one light-emitting unit has substantially the same structure as the EL layer 103 shown in FIG. 1(A). That is, the light-emitting device shown in FIG. 1(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) or FIG. 1(B) can be said to be a light-emitting device having one light-emitting unit. That is, the light-emitting device shown in FIG. 1(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) or FIG. 1(B) can be said to be a light-emitting device having one light-emitting unit. That is, the light-emitting device shown in FIG. 1(C) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) or FIG. 1(B) can be said to be a light-emitting device having one light-emitting unit.

[0110] In FIG. 1(C), between the anode 501 and the cathode 502, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 respectively correspond to the anode 101 and the cathode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. Also, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures. In FIG. 1(C), between the anode 501 and the cathode 502, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 respectively correspond to the anode 101 and the cathode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. Also, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures. In FIG. 1(C), between the anode 501 and the cathode 502, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked, and a charge generation layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The anode 501 and the cathode 502 respectively correspond to the anode 101 and the cathode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. Also, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures. The anode 501 and the cathode 502 respectively correspond to the anode 101 and the cathode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. The anode 501 and the cathode 502 respectively correspond to the anode 101 and the cathode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. Also, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures. The anode 501 and the cathode 502 respectively correspond to the anode 101 and the cathode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. Also, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same structure or different structures.

[0111] The charge generation layer 513 has a function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied between the anode 501 and the cathode 502. That is, in FIG. 1(C), when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, The charge generation layer 513 has a function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied between the anode 501 and the cathode 502. That is, in FIG. 1(C), when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, when a voltage is applied so that the potential of the anode is higher than the potential of the cathode, In combination, the charge generation layer 513 may inject electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512. It only needs to be something that injects holes into the second light-emitting unit 512.

[0112] The charge generation layer 513 is preferably formed with the same configuration as the charge generation layer 116 described in FIG. 1(B). Since the composite material of the organic compound and the metal oxide is excellent in carrier injection property and carrier transport property, low-voltage driving and low-current driving can be realized. In addition, when the surface on the anode side of the light-emitting unit is in contact with the charge generation layer 513, the charge generation layer 513 can also serve as the hole injection layer of the light-emitting unit, so the light-emitting unit may not be provided with a hole injection layer. It is also possible. When the charge generation layer 513 is provided with an electron injection buffer layer 119, since the electron injection buffer layer 119 serves as the electron injection layer in the light-emitting unit on the anode side, it is not always necessary to form an electron injection layer in the light-emitting unit on the anode side. When the charge generation layer 513 is provided with an electron injection buffer layer 119, since the electron injection buffer layer 119 serves as the electron injection layer in the light-emitting unit on the anode side, it is not always necessary to form an electron injection layer in the light-emitting unit on the anode side. It is not necessary.

[0113] In FIG. 1(C), a light-emitting device having two light-emitting units was described, but the same can be similarly applied to a light-emitting device in which three or more light-emitting units are stacked. As in the light-emitting device according to the present embodiment, by arranging a plurality of light-emitting units between a pair of electrodes with the charge generation layer 513 interposed therebetween, high-brightness light emission can be achieved while keeping the current density low, and a longer-life element can be realized. In addition, a light-emitting device that can be driven at a low voltage and has low power consumption can be realized.

[0114] In FIG. 1(C), a light-emitting device having two light-emitting units was described, but the same can be similarly applied to a light-emitting device in which three or more light-emitting units are stacked. By arranging a plurality of light-emitting units between a pair of electrodes with the charge generation layer 513 interposed therebetween, high-brightness light emission can be achieved while keeping the current density low, and a longer-life element can be realized. As in the light-emitting device according to the present embodiment, by arranging a plurality of light-emitting units between a pair of electrodes with the charge generation layer 513 interposed therebetween, high-brightness light emission can be achieved while keeping the current density low, and a longer-life element can be realized. In addition, a light-emitting device that can be driven at a low voltage and has low power consumption can be realized. In addition, by making the emission colors of the respective light-emitting units different, the entire light-emitting device and In addition, a light-emitting device that can be driven at a low voltage and has low power consumption can be realized.

[0115] In addition, by making the emission colors of the respective light-emitting units different, the entire light-emitting device and Thus, light emission of a desired color can be obtained. For example, in a light-emitting device having two light-emitting units in a vice, by obtaining red and green light-emitting colors with the first light-emitting unit and blue light-emitting color with the second light-emitting unit, it is also possible to obtain a light-emitting device that emits white light as a whole of the light-emitting device. Further, in a light-emitting device having three light-emitting units, with the first light-emitting unit emitting blue light, the second light-emitting unit emitting a light-emitting color having a spectrum in the range from green to red, and the third light-emitting unit emitting blue light, it is possible to disperse the load on the blue light-emitting unit and obtain a light-emitting device with better lifespan.

[0116] In addition, each layer such as the above-described EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the charge generation layer, and the electrodes can be formed, for example, by methods such as vapor deposition (including vacuum vapor deposition), droplet ejection method (also called inkjet method), coating method, gravure printing method, etc. Further, they may contain low molecular weight materials, medium molecular weight materials (including oligomers and dendrimers), or high molecular weight materials.

[0117] (Embodiment 3) In this embodiment, a light-emitting device using the light-emitting device described in Embodiment 1 and Embodiment 2 will be described.

[0118] In this embodiment, a light-emitting device manufactured using the light-emitting device described in Embodiment 1 and Embodiment 2 will be described with reference to FIG. 2. Note that FIG. 2(A) is a top view showing the light-emitting device, and FIG. 2(B) is a cross-sectional view obtained by cutting FIG. 2(A) along A - B and C - D. This light-emitting device controls the light emission of the light-emitting device, and as a driving circuit unit (source) indicated by a dotted line The pixel portion 602 includes a driver circuit portion (gate line driver circuit) 603. In addition, 604 is a sealing substrate, 605 is a sealing material, and the inside surrounded by the sealing material 605 has become space 607.

[0119] The lead wiring 608 is connected to the source line driver circuit 601 and the gate line driver circuit 603. The wiring is for transmitting the signals to be input, and the FPC (flexible printed circuit board) is the external input terminal. Video signal, clock signal, start signal, reset signal, etc. from the 609 Although only the FPC is shown here, the FPC has a printed wiring board. The light emitting device in this specification may be a light emitting device. This includes not only the device itself, but also the state in which an FPC or PWB is attached to it. do.

[0120] Next, the cross-sectional structure will be described with reference to FIG. A source line driver circuit 601 and a pixel portion are formed. 6, one pixel in the pixel area 602 is shown.

[0121] The element substrate 610 may be a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or the like. FRP (Fiber Reinforced Plastics), PVF (Polyvinyl It is made using a plastic substrate made of materials such as fluoride, polyester, or acrylic. That's good.

[0122] The structure of the transistors used in the pixels and the driver circuits is not particularly limited. The transistor may be a top-type transistor or a staggered type transistor. Either a gate-type transistor or a bottom-gate type transistor may be used. The semiconductor material used for the transistor is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, etc. can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used. The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of an amorphous semiconductor, a semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or a semiconductor having a crystal region in part) may be used. Using a semiconductor having crystallinity is preferable because it can suppress deterioration of transistor characteristics. Here, in addition to the transistors provided in the above-described pixel and driving circuit, for semiconductor devices such as transistors used for a touch sensor described later, it is preferable to apply an oxide semiconductor. In particular, it is preferable to apply an oxide semiconductor having a wider bandgap than silicon. By using an oxide semiconductor having a wider bandgap than silicon, the current in the off state of the transistor can be reduced. The above-described oxide semiconductor preferably contains at least indium (In) or zinc (Zn). Further, it is more preferable that it is an oxide semiconductor containing an oxide represented by In-M-Zn-based oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0123] In particular, as the semiconductor layer, it has a plurality of crystal parts, and the c-axis of the crystal part is the surface to be formed of the semiconductor layer. The semiconductor material used for the transistor is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, etc. can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used. The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of an amorphous semiconductor, a semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or a semiconductor having a crystal region in part) may be used. Using a semiconductor having crystallinity is preferable because it can suppress deterioration of transistor characteristics. Here, in addition to the transistors provided in the above-described pixel and driving circuit, for semiconductor devices such as transistors used for a touch sensor described later, it is preferable to apply an oxide semiconductor. In particular, it is preferable to apply an oxide semiconductor having a wider bandgap than silicon. By using an oxide semiconductor having a wider bandgap than silicon, the current in the off state of the transistor can be reduced.

[0124] The above-described oxide semiconductor preferably contains at least indium (In) or zinc (Zn). Further, it is more preferable that it is an oxide semiconductor containing an oxide represented by In-M-Zn-based oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf). Either a gate-type transistor or a bottom-gate type transistor may be used. The semiconductor material used for the transistor is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, etc. can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used. The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of an amorphous semiconductor, a semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or a semiconductor having a crystal region in part) may be used. Using a semiconductor having crystallinity is preferable because it can suppress deterioration of transistor characteristics. Here, in addition to the transistors provided in the above-described pixel and driving circuit, for semiconductor devices such as transistors used for a touch sensor described later, it is preferable to apply an oxide semiconductor. In particular, it is preferable to apply an oxide semiconductor having a wider bandgap than silicon. By using an oxide semiconductor having a wider bandgap than silicon, the current in the off state of the transistor can be reduced. The above-described oxide semiconductor preferably contains at least indium (In) or zinc (Zn). Further, it is more preferable that it is an oxide semiconductor containing an oxide represented by In-M-Zn-based oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0125] In particular, as the semiconductor layer, it has a plurality of crystal parts, and the c-axis of the crystal part is the surface to be formed of the semiconductor layer. The semiconductor material used for the transistor is not particularly limited, and for example, silicon, germanium, silicon carbide, gallium nitride, etc. can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used. The crystallinity of the semiconductor material used for the transistor is also not particularly limited, and any of an amorphous semiconductor, a semiconductor having crystallinity (microcrystalline semiconductor, polycrystalline semiconductor, single crystal semiconductor, or a semiconductor having a crystal region in part) may be used. Using a semiconductor having crystallinity is preferable because it can suppress deterioration of transistor characteristics. Here, in addition to the transistors provided in the above-described pixel and driving circuit, for semiconductor devices such as transistors used for a touch sensor described later, it is preferable to apply an oxide semiconductor. In particular, it is preferable to apply an oxide semiconductor having a wider bandgap than silicon. By using an oxide semiconductor having a wider bandgap than silicon, the current in the off state of the transistor can be reduced.

[0126] The above-described oxide semiconductor preferably contains at least indium (In) or zinc (Zn). Further, it is more preferable that it is an oxide semiconductor containing an oxide represented by In-M-Zn-based oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf). An oxide semiconductor film that is oriented perpendicular to the upper surface of the semiconductor layer and has no grain boundaries between adjacent crystal parts is preferably used. It is preferable to use an oxide semiconductor film.

[0127] By using such a material as the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0128] In addition, due to its low off-current, the transistor having the above-described semiconductor layer can hold the charge accumulated in the capacitor through the transistor for a long period of time. By applying such a transistor to the pixel, it is possible to maintain the gradation of the image displayed in each display area while stopping the driving circuit. As a result, an electronic device with extremely low power consumption can be realized.

[0129] For the purpose of stabilizing the characteristics of the transistor, etc., it is preferable to provide an underlayer film. As the underlayer film, an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a nitrided silicon oxide film can be used and can be formed as a single layer or in a laminated structure. The underlayer film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, a MOCVD (Metal Organic CVD) method, etc.), an ALD ( Atomic Layer Deposition) method, a coating method, a printing method, etc. Note that the underlayer film may not be provided if not necessary.

[0130] Note that FET623 indicates one of the transistors formed in the drive circuit unit 601. The drive circuit is formed of various CMOS circuits, PMOS circuits, or NMOS circuits. That's all. In this embodiment, a driver-integrated type in which a driving circuit is formed on a substrate is shown. However, this is not necessarily required, and the driving circuit can be formed outside the substrate instead of on the substrate. .

[0131] Also, the pixel portion 602 is formed by a plurality of pixels including a switching FET 611, a current control FET 612, and an anode 613 electrically connected to its drain. However, it is not limited to this, and a pixel portion combined with three or more FETs and a capacitive element may be used. Note that an insulator 614 is formed covering the end portion of the anode 613. Here, it can be formed by using a positive photosensitive acrylic resin film.

[0132] In addition, in order to improve the coating property of the EL layer and the like formed later, a curved surface having a curvature is formed at the upper end or the lower end of the insulator 614. For example, when positive photosensitive acrylic is used as the material of the insulator 614, it is preferable to provide a curved surface having a radius of curvature (0. 2 μm to 3 μm) only at the upper end of the insulator 614. Also, as the insulator 614, either a negative photosensitive resin or a positive photosensitive resin can be used.

[0133] An EL layer 616 and a cathode 617 are respectively formed on the anode 613. Here, as the material used for the anode 613, it is desirable to use a material having a large work function. For example, an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, etc., in addition to a single-layer film, a laminate of a titanium nitride film and a film mainly composed of aluminum, titanium nitride film and a film mainly composed of aluminum, etc.

[0134] On the anode 613, an EL layer 616 and a cathode 617 are respectively formed. Here, as the material used for the anode 613, it is desirable to use a material having a large work function. For example, for example, an ITO film, or an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt% of zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, a Pt film, etc., in addition to a single-layer film, a laminate of a titanium nitride film and a film mainly composed of aluminum, a laminate of a titanium nitride A three-layer structure or the like including a film, a film mainly composed of aluminum, and a titanium nitride film can be used. When a laminated structure is used, the resistance as wiring is low, good ohmic contact can be achieved, and it can further function as an anode.

[0135] In addition, the EL layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an inkjet method, and a spin coating method. The EL layer 616 includes the configuration as described in Embodiment 1 and Embodiment 2. As other materials constituting the EL layer 616, a low molecular compound or a high molecular compound (including oligomers and dendrimers) may be used.

[0136] Furthermore, as the material used for the cathode 617 formed on the EL layer 616, a material with a small work function (Al, Mg, Li, Ca, or alloys and compounds thereof (such as MgAg, MgIn, AlLi, etc.)) is preferably used. When the light generated in the EL layer 616 passes through the cathode 617, a laminated structure of a thin metal film with a reduced thickness and a transparent conductive film (ITO, indium oxide containing 2 to 20 wt% of zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) is preferably used as the cathode 617.

[0137] Note that a light-emitting device is formed by the anode 613, the EL layer 616, and the cathode 617. The light-emitting device is the light-emitting device described in Embodiment 1 and Embodiment 2. In addition, although a plurality of light-emitting devices are formed in the pixel portion, in the light-emitting device of the present embodiment, both the light-emitting device described in Embodiment 1 and Embodiment 2 and a light-emitting device having other configurations may be included. ​

[0138] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, the structure is formed such that a light-emitting device 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. Note that the space 607 is filled with a filling material, and in addition to the case where an inert gas (such as nitrogen or argon) is filled, there is also a case where it is filled with a sealing material. It is a preferable configuration to form a concave portion in the sealing substrate and provide a drying material therein to suppress deterioration due to the influence of moisture.

[0139] Note that it is preferable to use an epoxy-based resin or glass frit for the sealing material 605. Also, these materials are desirably materials that hardly transmit moisture and oxygen. In addition, as the material used for the sealing substrate 604, in addition to a glass substrate or a quartz substrate, a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (polyvinyl fluoride), polyester, or acrylic can be used. einforced Plastics), PVF (polyvinyl fluoride), polyester or acrylic can be used.

[0140] Although not shown in FIG. 2, a protective film may be provided on the cathode. The protective film may be formed of an organic resin film or an inorganic insulating film. Also, the protective film may be formed so as to cover the exposed portion of the sealing material 605. Further, the protective film can be provided so as to cover the exposed side surfaces such as the surfaces and side surfaces of the pair of substrates, the sealing layer, and the insulating layer.

[0141] For the protective film, a material that hardly transmits impurities such as water can be used. Therefore, it is possible to effectively suppress the diffusion of impurities such as water from the outside to the inside.

[0142] As materials for forming the protective film, oxides, nitrides, fluorides, sulfides, ternary compounds, metals or polymers can be used. For example, aluminum oxide, hafnium oxide, ha fnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide , titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide , cerium oxide, scandium oxide, erbium oxide, vanadium oxide or indium ium oxide and other materials containing such components, materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, nit ride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride or gallium nitride and other materials containing such components, nitrides containing titanium and aluminum, oxides containing titanium and aluminum , oxides containing aluminum and zinc, sulfides containing manganese and zinc, sulfides containing cerium and strontium, oxides containing erbium and aluminum, oxides containing yttrium and zirconium and other materials containing such components can be used.

[0143] The protective film is preferably formed using a film-forming method with good step coverage. One such method is atomic layer deposition (ALD). Materials that can be formed using the ALD method are preferably used for the protective film. By using the ALD method, a dense protective film with reduced defects such as cracks and pinholes or a uniform thickness can be formed. Also, the damage to the processing member during the formation of the protective film can be reduced. For example, by forming the protective film using the ALD method, a surface with a complex uneven shape or a tap

[0144] It is possible to form a uniform protective film with few defects on the top, sides and back of the panel. .

[0145] As described above, the light-emitting devices described in the first and second embodiments were used to manufacture the Thus, a light emitting device having such a structure can be obtained.

[0146] The light emitting device of the present embodiment is the same as the light emitting device of the first and second embodiments. Since the semiconductor device uses the same material, it is possible to obtain a light-emitting device with excellent characteristics. The light emitting devices according to the first and second embodiments have a long life. Therefore, the light emitting device can have good reliability. Since the light emitting device using the light emitting device described in 2 has a good light emitting efficiency, it is a light emitting device with low power consumption. It may be an optical device.

[0147] In FIG. 3, a light-emitting device that emits white light is formed, and a colored layer (color filter) is provided. FIG. 3A shows an example of a full-color light-emitting device. An insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, 1008, A first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral portion 1042, and a pixel portion 1040 , a driving circuit section 1041, anodes 1024W, 1024R, 1024G, and 10 24B, partition wall 1025, EL layer 1028, cathode 1029 of the light-emitting device, sealing substrate 103 1, sealing material 1032, etc. are shown.

[0148] In addition, in FIG. 3(A), the colored layers (red colored layer 1034R, green colored layer 1034G, blue The colored layer 1034B is provided on a transparent substrate 1033. 035 may be further provided. A transparent substrate 1 provided with a coloring layer and a black matrix 033 is aligned and fixed to the substrate 1001. Note that the coloring layer and the black matrix 1035 is covered with an overcoat layer 1036. Also, in FIG. 3(A), there are a light-emitting layer through which light does not pass through the coloring layer to the outside, and a light-emitting layer through which light passes through each coloring layer to the outside and the light that does not pass through the coloring layer is white, and the light that passes through the coloring layer is red, green, or blue Therefore, an image can be expressed with four-color pixels.

[0149] In FIG. 3(B), an example is shown in which the coloring layers (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. In this way, the coloring layer may be provided between the substrate 1001 and the sealing substrate 1031.

[0150] Also, in the light-emitting device described above, the light-emitting device has a structure (bottom emission type) that emits light from the side of the substrate 1001 on which the FET is formed, but it may be a light-emitting device having a structure (top emission type) that emits light from the side of the sealing substrate 1031. A cross-sectional view of the top emission type light-emitting device is shown in FIG. 4. In this case, the substrate 1001 can be a substrate that does not transmit light. Until a connection electrode connecting the FET and the anode of the light-emitting device is fabricated, it is formed in the same manner as the bottom emission type light-emitting device. Then, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also serve as a planarization film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film, as well as other known materials.

[0151] ​​​​​​​​ The anodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are anodes here but may be formed as cathodes. Also, in the case of a top-emission type light-emitting device as shown in FIG. 4, it is preferable that the anode be a reflective electrode. The configuration of the EL layer 1028 is the same as the configuration described for the EL layer 103 in Embodiment 1 and Embodiment 2, and moreover, the element structure is such that white light emission can be obtained.

[0152] In the top-emission structure as shown in FIG. 4, sealing can be performed with a sealing substrate 1031 provided with a coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The coloring layer (red coloring layer 1034R, green coloring layer 1034G, blue coloring layer 1034B) and the black matrix may be covered by an overcoat layer 1036. Note that the sealing substrate 1031 uses a substrate having translucency. Also, although an example of full-color display using four colors of red, green, blue, and white is shown here, it is not particularly limited, and full-color display may be performed using four colors of red, yellow, green, and blue or three colors of red, green, and blue.

[0153] In a top-emission type light-emitting device, application of a microcavity structure can be suitably performed. A light-emitting device having a microcavity structure is obtained by using a reflective electrode as the anode and a semi-transmissive / semi-reflective electrode as the cathode. Between the reflective electrode and the semi-transmissive / semi-reflective electrode, there is at least an EL layer and at least a light-emitting layer serving as a light-emitting region.

[0154] Note that the reflective electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100 in %, and the resistivity of the film is 1×10 -2 Ωcm or less. Further, the semi-transmissive / semi-reflective electrode has a reflectance of visible light of 20% to 80%, preferably 40% to 70%, and the resistivity of the film is 1×10 Ωcm or less. -2

[0155] The light emitted from the light-emitting layer contained in the EL layer is reflected by the reflective electrode and the semi-transmissive / semi-reflective electrode and resonates.

[0156] By changing the thicknesses of the transparent conductive film, the above-described composite material, the carrier transport material, etc., the optical distance between the reflective electrode and the semi-transmissive / semi-reflective electrode can be changed. As a result, the light of the resonant wavelength can be enhanced and the light of the non-resonant wavelength can be attenuated between the reflective electrode and the semi-transmissive / semi-reflective electrode.

[0157] Note that the light (the first reflected light) reflected back by the reflective electrode causes significant interference with the light (the first incident light) directly incident on the semi-transmissive / semi-reflective electrode from the light-emitting layer. Therefore, it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n - 1)λ / 4 (where n is a natural number of 1 or more and λ is the wavelength of the amplified light emission). By adjusting the optical distance, the phases of the first reflected light and the first incident light can be matched to further amplify the light emission from the light-emitting layer.

[0158] In the above configuration, the EL layer may have a structure having a plurality of light-emitting layers or a structure having a single light-emitting layer. For example, in combination with the configuration of the tandem type light-emitting device described above, a plurality of EL layers are provided with a charge generation layer sandwiched between them in one light-emitting device, and each EL ​​​​​​​​​​It may be applied to a configuration in which one or more light-emitting layers are formed on a layer.

[0159] By having a microcavity structure, it is possible to enhance the forward emission intensity of a specific wavelength, so that power consumption can be reduced. In the case of a light-emitting device that displays an image with four sub-pixels of red, yellow, green, and blue, in addition to the luminance improvement effect due to yellow emission, a microcavity structure adapted to the wavelength of each color can be applied to all the sub-pixels, resulting in a light-emitting device with good characteristics.

[0160] The light-emitting device according to the present embodiment uses the light-emitting devices described in Embodiment 1 and Embodiment 2, so that a light-emitting device having good characteristics can be obtained. Specifically, the light-emitting devices described in Embodiment 1 and Embodiment 2 are light-emitting devices with a long lifespan, so that a highly reliable light-emitting device can be obtained. Further, since the light-emitting device using the light-emitting devices described in Embodiment 1 and Embodiment 2 has good luminous efficiency, it can be made into a light-emitting device with low power consumption.

[0161] So far, the active matrix type light-emitting device has been described. From below, the passive matrix type light-emitting device will be described. FIG. 5 shows a passive matrix type light-emitting device fabricated by applying the present invention. Note that FIG. 5(A) is a perspective view showing the light-emitting device, and FIG. 5(B) is a cross-sectional view obtained by cutting FIG. 5(A) along the X-Y plane. In FIG. 5, an EL layer 955 is provided between an electrode 952 and an electrode 956 on a substrate 951. The end of the electrode 952 is covered with an insulating layer 953. Then, a partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained. As described above, the light-emitting device can be preferably used as a display device for expressing an image because it is possible to control each of a large number of minute light-emitting devices arranged in a matrix. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained. The side walls of the partition layer 954 have an inclination such that the distance between one side wall and the other side wall decreases as it approaches the substrate surface. That is, the cross-section of the partition layer 954 in the short side direction has a trapezoidal shape, and the bottom side (the side facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is shorter than the upper side (the side facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent defects in the light-emitting device caused by static electricity or the like. Also, in a passive matrix type light-emitting device, the light-emitting devices described in Embodiment 1 and Embodiment 2 are used, and a light-emitting device with good reliability or a light-emitting device with low power consumption can be obtained.

[0162] As described above, the light-emitting device can be preferably used as a display device for expressing an image because it is possible to control each of a large number of minute light-emitting devices arranged in a matrix. As described above, the light-emitting device can be preferably used as a display device for expressing an image because it is possible to control each of a large number of minute light-emitting devices arranged in a matrix. As described above, the light-emitting device can be preferably used as a display device for expressing an image because it is possible to control each of a large number of minute light-emitting devices arranged in a matrix.

[0163] Also, this embodiment can be freely combined with other embodiments.

[0164] (Embodiment 4) In this embodiment, an example of using the light-emitting devices described in Embodiment 1 and Embodiment 2 as a lighting device will be described with reference to FIG. 6. FIG. 6(B) is a top view of the lighting device, and FIG. 6(A) is a cross-sectional view taken along the line e-f in FIG. 6(B). In this embodiment, an example of using the light-emitting devices described in Embodiment 1 and Embodiment 2 as a lighting device will be described with reference to FIG. 6. FIG. 6(B) is a top view of the lighting device, and FIG. 6(A) is a cross-sectional view taken along the line e-f in FIG. 6(B). In this embodiment, an example of using the light-emitting devices described in Embodiment 1 and Embodiment 2 as a lighting device will be described with reference to FIG. 6. FIG. 6(B) is a top view of the lighting device, and FIG. 6(A) is a cross-sectional view taken along the line e-f in FIG. 6(B).

[0165] In the lighting device in this embodiment, an anode 401 is formed on a light-transmissive substrate 400 which is a support. The anode 401 corresponds to the anode 101 in Embodiment 2. When extracting light from the anode 401 side, the anode 401 is formed of a light-transmissive material. In the lighting device in this embodiment, an anode 401 is formed on a light-transmissive substrate 400 which is a support. The anode 401 corresponds to the anode 101 in Embodiment 2. When extracting light from the anode 401 side, the anode 401 is formed of a light-transmissive material. In the lighting device in this embodiment, an anode 401 is formed on a light-transmissive substrate 400 which is a support. The anode 401 corresponds to the anode 101 in Embodiment 2. When extracting light from the anode 401 side, the anode 401 is formed of a light-transmissive material.

[0166] A pad 412 for supplying voltage to the cathode 404 is formed on the substrate 400.

[0167] An EL layer 403 is formed on the anode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1 and Embodiment 2, or the combined configuration of the light-emitting units 511, 512 and the charge generation layer 513. For these configurations, please refer to the relevant descriptions. An EL layer 403 is formed on the anode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1 and Embodiment 2, or the combined configuration of the light-emitting units 511, 512 and the charge generation layer 513. For these configurations, please refer to the relevant descriptions. An EL layer 403 is formed on the anode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1 and Embodiment 2, or the combined configuration of the light-emitting units 511, 512 and the charge generation layer 513. For these configurations, please refer to the relevant descriptions. An EL layer 403 is formed on the anode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1 and Embodiment 2, or the combined configuration of the light-emitting units 511, 512 and the charge generation layer 513. For these configurations, please refer to the relevant descriptions.

[0168] The cathode 404 is formed to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 in Embodiment 2. When extracting light from the anode 401 side, the cathode 404 is formed of a material with high reflectivity. The cathode 404 is connected to the pad 412 to supply voltage. The cathode 404 is formed to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 in Embodiment 2. When extracting light from the anode 401 side, the cathode 404 is formed of a material with high reflectivity. The cathode 404 is connected to the pad 412 to supply voltage. The cathode 404 is formed to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 in Embodiment 2. When extracting light from the anode 401 side, the cathode 404 is formed of a material with high reflectivity. The cathode 404 is connected to the pad 412 to supply voltage. The cathode 404 is formed to cover the EL layer 403. The cathode 404 corresponds to the cathode 102 in Embodiment 2. When extracting light from the anode 401 side, the cathode 404 is formed of a material with high reflectivity. The cathode 404 is connected to the pad 412 to supply voltage.

[0169] As described above, the lighting device in this embodiment has a light-emitting device having an anode 401, an EL layer 403, and a cathode 404. Since the light-emitting device has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption. As described above, the lighting device in this embodiment has a light-emitting device having an anode 401, an EL layer 403, and a cathode 404. Since the light-emitting device has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption. As described above, the lighting device in this embodiment has a light-emitting device having an anode 401, an EL layer 403, and a cathode 404. Since the light-emitting device has high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption.

[0170] The substrate 400 on which a light-emitting device having the above configuration is formed and the sealing substrate 407 are fixed and sealed using sealing materials 405, 406, and thus the lighting device is completed. Either of the sealing materials 405, 406 can be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), which can adsorb moisture and lead to an improvement in reliability. The substrate 400 on which a light-emitting device having the above configuration is formed and the sealing substrate 407 are fixed and sealed using sealing materials 405, 406, and thus the lighting device is completed. Either of the sealing materials 405, 406 can be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), which can adsorb moisture and lead to an improvement in reliability. The substrate 400 on which a light-emitting device having the above configuration is formed and the sealing substrate 407 are fixed and sealed using sealing materials 405, 406, and thus the lighting device is completed. Either of the sealing materials 405, 406 can be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), which can adsorb moisture and lead to an improvement in reliability. The substrate 400 on which a light-emitting device having the above configuration is formed and the sealing substrate 407 are fixed and sealed using sealing materials 405, 406, and thus the lighting device is completed. Either of the sealing materials 405, 406 can be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), which can adsorb moisture and lead to an improvement in reliability. The substrate 400 on which a light-emitting device having the above configuration is formed and the sealing substrate 407 are fixed and sealed using sealing materials 405, 406, and thus the lighting device is completed. Either of the sealing materials 405, 406 can be used. Also, a desiccant can be mixed into the inner sealing material 406 (not shown in FIG. 6(B)), which can adsorb moisture and lead to an improvement in reliability.

[0171] Also, a part of the pad 412 and the anode 401 is provided to extend outside the sealing materials 405 and 406. By doing so, it can be used as an external input terminal. Also, an IC chip 420 or the like with a converter or the like mounted thereon may be provided.

[0172] As described above, the lighting device according to the present embodiment uses the light-emitting devices described in Embodiment 1 and Embodiment 2 for the EL element, and can be a light-emitting device with good reliability. Also, it can be a light-emitting device with low power consumption.

[0173] (Embodiment 5) In the present embodiment, an example of an electronic device including the light-emitting devices described in Embodiment 1 and Embodiment 2 in a part thereof will be described. The light-emitting devices described in Embodiment 1 and Embodiment 2 have a good lifespan and are light-emitting devices with good reliability. As a result, the electronic device described in the present embodiment can be an electronic device having a light-emitting part with good reliability.

[0174] Examples of electronic devices to which the above light-emitting device is applied include, for example, a television device (also referred to as a TV or a television receiver), a monitor for a computer, a digital camera, a digital video camera, a digital photo frame, a mobile phone (also referred to as a mobile phone or a mobile phone device), a portable game machine, a portable information terminal, an audio reproduction device, a large game machine such as a pachinko machine and the like. Specific examples of these electronic devices are shown below.

[0175] FIG. 7(A) shows an example of a television device. The television device has a display unit 7103 incorporated in a housing 710 1. Also, here, the housing is supported by a stand 7105 ​​​​​It shows a configuration that supports 7101. The display unit 7103 can display video. It is possible, and the display unit 7103 is configured by arranging the light-emitting devices described in Embodiment 1 and Embodiment 2 in a matrix.

[0176] The operation of the television device can be performed by the operation switches provided in the housing 7101 or a separate remote control operation machine 7110. The operation keys 7109 provided on the remote control operation machine 7110 can be used to operate the channel and volume, and the video displayed on the display unit 7103 can be operated. Further, the remote control operation machine 7110 may be provided with a display unit 7107 for displaying the information output from the remote control operation machine 7110 itself.

[0177] The television device is configured to include a receiver, a modem, etc. The receiver can receive general television broadcasts, and can further communicate with a wired or wireless communication network via a modem, enabling one-way (sender to receiver) or two-way (sender and receiver, or between receivers, etc.) information communication.

[0178] Figure 7(B1) shows a computer, including a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer is manufactured by arranging the light-emitting devices described in Embodiment 1 and Embodiment 2 in a matrix and using them for the display unit 7203. The computer in Figure 7(B1) may also be in the form shown in Figure 7(B2). The computer in Figure 7(B2) uses a second display unit 7 instead of the keyboard 7204 and the pointing device 7206 210 is provided. The second display unit 7210 is a touch panel type, and the input display displayed on the second display unit 7210 can be operated with a finger or a dedicated pen to perform input. Further, the second display unit 7210 can display not only input displays but also other images. Also, the display unit 7203 may be a touch panel. By connecting the two screens with a hinge, it is possible to prevent problems such as damaging or breaking the screens when storing or transporting.

[0179] FIG. 7(C) shows an example of a mobile terminal. The mobile phone includes, in addition to a display unit 7402 incorporated in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone has a display unit 7402 manufactured by arranging the light-emitting devices described in Embodiment 1 and Embodiment 2 in a matrix.

[0180] The mobile terminal shown in FIG. 7(C) can be configured to input information by touching the display unit 7402 with a finger or the like. In this case, operations such as making a call or creating an email can be performed by touching the display unit 7402 with a finger

[0181] The screen of the display unit 7402 mainly has three modes. The first is a display mode mainly for displaying images, the second is an input mode mainly for inputting information such as characters. The third is a display + input mode in which the two modes of the

[0182] display mode and the input mode are mixed. For example, when making a call or creating an Set it as the main character input mode, and perform the input operation on the characters displayed on the screen. In this case , it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402 .

[0183] Also, by providing a detection device having sensors such as a gyro and an acceleration sensor inside the mobile terminal, the orientation (portrait or landscape) of the mobile terminal can be determined, and the display on the screen of the display unit 7402 can be automatically switched .

[0184] Also, the switching of the screen mode is performed by touching the display unit 7402 or operating the operation button 7403 of the housing 7401. Also, it can be switched according to the type of image displayed on the display unit 7402 . For example, if the image signal displayed on the display unit is video data, it is switched to the display mode, and if it is text data, it is switched to the input mode .

[0185] Also, in the input mode, when the signal detected by the optical sensor of the display unit 7402 is detected and there is no input by the touch operation of the display unit 7402 for a certain period, the screen mode may be controlled to be switched from the input mode to the display mode .

[0186] The display unit 7402 can also function as an image sensor. For example, by touching the display unit 7402 with the palm or finger and imaging the palm print, fingerprint, etc., personal authentication can be performed . Also, if a backlight that emits near-infrared light or a sensing light source that emits near-infrared light is used for the display unit, finger veins, palm veins, etc. can also be imaged .

[0187] Note that the configuration shown in this embodiment appropriately combines the configurations shown in Embodiments 1 to 4 ​​​​They can be used in combination.

[0188] As described above, the light-emitting device according to Embodiment 1 and Embodiment 2 is suitable for a very wide range of applications, and this light-emitting device can be applied to electronic devices in all fields. By using the light-emitting device described in Embodiment 1 and Embodiment 2, a highly reliable electronic device can be obtained.

[0189] FIG. 8(A) is a schematic diagram showing an example of a cleaning robot.

[0190] The cleaning robot 5100 has a display 5101 arranged on the upper surface, a plurality of cameras 5102 arranged on the side surface, a brush 5103, and operation buttons 5104. Although not shown, tires, suction ports, etc. are provided on the lower surface of the cleaning robot 5100. The cleaning robot 5100 is also provided with various sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, a light sensor, and a gyro sensor. In addition, the cleaning robot 5 100 is provided with wireless communication means.

[0191] The cleaning robot 5100 can move automatically, detect dust 5120, and suck dust from the suction port provided on the lower surface.

[0192] In addition, the cleaning robot 5100 can analyze the image taken by the camera 5102 and determine the presence or absence of obstacles such as walls, furniture, or steps. Also, when an object that is likely to get caught in the brush 5103 such as wiring is detected by image analysis, the rotation of the brush 5103 can be stopped.

[0193] The display 5101 can display the remaining battery level, the amount of dust sucked, etc. It is also possible to display on the display 5101 the path traveled by the cleaning robot 5100. Further, the display 5101 may be a touch panel, and the operation buttons 5104 may be provided on the display 5101.

[0194] The cleaning robot 5100 can communicate with a mobile electronic device 5140 such as a smartphone. The image captured by the camera 5102 can be displayed on the mobile electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when away from home. Also, the display on the display 5101 can be confirmed on a mobile electronic device 5140 such as a smartphone.

[0195] The light-emitting device according to one aspect of the present invention can be used for the display 5101.

[0196] The robot 2100 shown in FIG. 8(B) includes an arithmetic unit 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a moving mechanism 2108.

[0197] The microphone 2102 has a function of detecting the user's voice and environmental sounds, etc. Also, the speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104.

[0198] The display 2105 has a function of displaying various information. The robot 2100 It is possible to display the information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. Also, the display 2105 can be a detachable information terminal, and by installing it at a fixed position of the robot 2100, charging and data transfer are made possible.

[0199] The upper camera 2103 and the lower camera 2106 have the function of imaging the surroundings of the robot 2100. Also, the obstacle sensor 2107 can detect the presence or absence of obstacles in the traveling direction when the robot 210 0 moves forward using the moving mechanism 2108. The robot 21 00 can recognize the surrounding environment and move safely by using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107. The light-emitting device according to one aspect of the present invention can be used for the display 2105.

[0200] FIG. 8(C) is a diagram showing an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, connection terminals 5006, a sensor 5007 (including functions for measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone 5008, a second display unit 5002, a support unit 5012, earphones 5013, etc. has .

[0201] The light-emitting device according to one aspect of the present invention can be used for the display unit 5001 and the second display unit 5002.

[0202] ​​FIG. 9 shows an example in which the light-emitting device described in Embodiment 1 and Embodiment 2 is used in an electric stand. The electric stand shown in FIG. 9 includes a housing 2001 and a light source 2002 . As the light source 2002, the lighting device described in Embodiment 3 may be used.

[0203] FIG. 10 shows an example in which the light-emitting device described in Embodiment 1 and Embodiment 2 is used as an indoor lighting device 3 001. Since the light-emitting devices described in Embodiment 1 and Embodiment 2 are highly reliable light-emitting devices, a highly reliable lighting device can be obtained. Also , since the light-emitting devices described in Embodiment 1 and Embodiment 2 can be made large in area, they can be used as large-area lighting devices. Further, since the light-emitting devices described in Embodiment 1 and Embodiment 2 are thin, they can be used as a lighting device with a reduced thickness.

[0204] The light-emitting devices described in Embodiment 1 and Embodiment 2 can also be mounted on the windshield or dashboard of an automobile. FIG. 11 shows one aspect in which the light-emitting devices described in Embodiment 1 and Embodiment 2 are used on the windshield or dashboard of an automobile. The display regions 5200 to 5203 are display regions provided using the light-emitting devices described in Embodiment 1 and Embodiment 2. The display regions 5200 and 5201 are display devices equipped with the light-emitting devices described in Embodiment 1 and Embodiment 2 provided on the windshield of an automobile. The light-emitting devices described in Embodiment 1 and Embodiment 2 are fabricated with an anode and a cathode made of electrodes having translucency.

[0205] 1 and Embodiment 2. As a result, it is possible to provide a so-called see-through display device in which the opposite side can be seen through. In the case of see-through display, even if it is installed on the windshield of an automobile, it can be installed without obstructing the view. When providing a transistor or the like for driving, it is preferable to use a transistor having translucency, such as an organic transistor made of an organic semiconductor material or a transistor using an oxide semiconductor.

[0206] The display area 5202 is a display device equipped with the light-emitting device described in Embodiment 1 and Embodiment 2 provided in the pillar portion. In the display area 5202, by projecting the video from the imaging means provided on the vehicle body, it is possible to complement the view blocked by the pillar. Similarly, the display area 5203 provided in the dashboard portion complements the view blocked by the vehicle body by projecting the video from the imaging means provided outside the vehicle, supplements the blind spot, and can enhance safety. By projecting the video so as to complement the invisible part, it is possible to perform safety confirmation more naturally without discomfort.

[0207] The display area 5203 can also provide various information by displaying navigation information, a speedometer, a tachometer, a travel distance, a fuel gauge, a gear state, an air conditioner setting, and the like. The display can be appropriately changed in its display items and layout according to the user's preference. Note that these information can also be provided in the display areas 5200 to 5203. Also, the display areas 5200 to 5203 can also be used as lighting devices.

[0208] Also, FIGS. 12(A) and (B) show a foldable portable information terminal 5150. The foldable mobile information terminal 5150 has a housing 5151, a display area 5152, and a bending part 515 3. Fig. 12(A) shows the mobile information terminal 5150 in the unfolded state. Fig. 12( B) shows the mobile information terminal 5150 in the folded state. Despite having a large display area 5152, the mobile information terminal 5150 is compact and highly portable when folded.

[0209] The display area 5152 can be folded in half by the bending part 5153. The bending part 515 3 is composed of a stretchable member and a plurality of support members. When folding, the stretchable member extends, and the bending part 5153 is folded with a radius of curvature of 2 mm or more, preferably 3 mm or more.

[0210] Note that the display area 5152 may be a touch panel (input / output device) equipped with a touch sensor (input device). The light-emitting device according to one aspect of the present invention can be used for the display area 5152.

[0211] Also, Figs. 13(A) to (C) show a foldable mobile information terminal 9310. Fig. 13 (A) shows the mobile information terminal 9310 in the unfolded state. Fig. 13(B) shows the mobile information terminal 9310 in a state where it is changing from one of the unfolded state or the folded state to the other. Fig. 13(C) shows the mobile information terminal 9310 in the folded state. The mobile information terminal 9310 is highly portable when folded and has an excellent display integrity with a seamless and wide display area when unfolded.

[0212] The display panel 9311 is supported by three housings 9315 connected by a hinge 9313 ​​​It should be noted that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). Further, the display panel 9311 can be reversibly deformed from the unfolded state of the portable information terminal 9310 to the folded state by bending it between the two housings 9315 via the hinge 9313. The light-emitting device according to one aspect of the present invention can be used for the display panel 9311. Also, the display panel 9311 can be reversibly deformed from the unfolded state of the portable information terminal 9310 to the folded state by bending it between the two housings 9315 via the hinge 9313. The light-emitting device according to one aspect of the present invention can be used for the display panel 9311.

Example

Example

[0213] In this example, the light-emitting devices 1 to 3 according to one aspect of the present invention and the comparative light-emitting devices 1 and 2 which are comparative examples will be described. The structural formulas of the organic compounds used in the light-emitting devices 1 to 3, the comparative light-emitting device 1, and the comparative light-emitting device 2 are shown below. (Method for manufacturing the light-emitting device 1) First, indium tin oxide (ITSO) containing silicon oxide was formed into a film on a glass substrate by a sputtering method to form the anode 101. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0214]

Chemical formula

[0215] (Method for manufacturing the light-emitting device 1) First, indium tin oxide (ITSO) containing silicon oxide was formed into a film on a glass substrate by a sputtering method to form the anode 101. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0216] Next, as a pretreatment for forming the light-emitting device on the substrate, the substrate surface was washed with water, baked at 200 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. After that, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 Pa, and vacuum evaporation

[0217] After that, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 Pa, and vacuum evaporation -4 was performed. ​In the heating chamber of the device, after performing vacuum baking at 170 °C for 30 minutes, the substrate was allowed to cool for about 30 minutes. It was allowed to cool.

[0218] Next, with the surface on which the anode 101 was formed facing downward, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in a vacuum evaporation apparatus, and N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and ALD-MP001Q (Analytical Workshop Co., Ltd., material serial number: 1S20170124) were co-evaporated in a weight ratio of 1:0.1 (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. -9H-fluorene-2-amine (abbreviation: PCBBiF) and ALD-MP001Q (Analytical Workshop Co., Ltd., material serial number: 1S20170124) were co-evaporated in a weight ratio of 1:0.1 (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. (=PCBBiF:ALD-MP001Q) to co-evaporate 10 nm to form a hole injection layer 111.

[0219] Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm, and then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0220] Subsequently, 7-[4-(10-phenyl-9-anthryl )phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) represented by the above structural formula (iii) and N,N'-(pyrene-1,6-diyl)bis[(6,N- Diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine (abbreviation: 1,6B nfAPrn-03) and were co-evaporated at a weight ratio of 1:0.03 (= cgDBCzPA: 1,6BnfA Prn-03) to form the light-emitting layer 113 with a thickness of 25 nm.

[0221] Thereafter, on the light-emitting layer 113, 2-[3'-(dibenzothiophen ene-4-yl)biphenyl-3-yl]dibenzof[h]quinoxaline (abbreviation: 2m DBTBPDBq-II) was evaporated to a thickness of 15 nm, and then the above structural formula (vi) represented by 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-f enanthroline (abbreviation: NBPhen) was evaporated to a thickness of 10 nm to form the electron transport layer 114.

[0222] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was evaporated to a thickness of 200 nm to form the cathode 102, thereby fabricating the light-emitting device 1 of this example.

[0223] (Fabrication method of light-emitting device 2) The light-emitting device 2 was fabricated in the same manner as the light-emitting device 1, except that PCBBiF in the light-emitting device 1 was replaced with N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d] furan-8-amine (abbreviation: BBABnf) represented by the above structural formula (vii). fabricated.

[0224] (Fabrication method of light-emitting device 3) The light-emitting device 3 was fabricated in the same manner as the light-emitting device 2, except that DBfBB1TP in the light-emitting device 2 was replaced with the above structural formula (viii). ​3,3'-(Naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviation: PCzN2) was used instead, and the device was fabricated in the same manner as the light-emitting device 2. Except for changing to

[0225] (Fabrication method of Comparative Light-Emitting Device 1) Comparative Light-Emitting Device 1 was fabricated in the same manner as the light-emitting device 1, except that 2mDBTBPDBq-II in the light-emitting device 1 was changed to cgDBCzPA. Except for changing to

[0226] (Fabrication method of Comparative Light-Emitting Device 2) Comparative Light-Emitting Device 2 was fabricated in the same manner as Comparative Light-Emitting Device 1, except that DBfBB1TP in Comparative Light-Emitting Device 1 was changed to PCzN2. Except for changing to

[0227] The element structures of the light-emitting devices 1 to 3, Comparative Light-Emitting Device 1, and Comparative Light-Emitting Device 2 are summarized in the following table. Except for changing to

[0228]

Table 1

[0229] In addition, the following table summarizes the HOMO level, LUMO level, and the electron mobility when the square root of the electric field strength [V / cm] of the organic compounds used in this example is 600. Except for changing to

[0230]

Table 2

[0231] After these light-emitting devices were sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting devices were not exposed to the air (a sealing material was applied around the elements, and UV treatment and heat treatment were performed at 80 °C for 1 hour during sealing), the initial characteristics of these light-emitting devices Except for changing to Except for changing to Measurements were made on the performance and reliability. The measurements were carried out at room temperature.

[0232] The luminance-current density characteristics of Light-Emitting Devices 1 to 3, Comparative Light-Emitting Device 1, and Comparative Light-Emitting Device 2 are shown in Fig. 14, the current efficiency-luminance characteristics are shown in Fig. 15, the luminance-voltage characteristics are shown in Fig. 16, the current-voltage characteristics are shown in Fig. 17, the external quantum efficiency-luminance characteristics are shown in Fig. 18, and the emission spectrum is shown in Fig. 19. Also, the main characteristics of each light-emitting device near 1000 cd / m are shown in Table 3. 2 near are shown in Table 3.

[0233] [Table 3]

[0234] From Figs. 14 to 19 and Table 3, it was found that all of Light-Emitting Devices 1 to 3, which are one aspect of the present invention, are blue light-emitting devices with good characteristics. Also, a graph showing the change in luminance with respect to the driving time at a current density of 50 mA / cm

[0235] is shown in Fig. 20. As shown in Fig. 20, for Light-Emitting Device 1, which is a light-emitting device of one aspect of the present invention, the luminance at the time when 300 hours have elapsed is 86% or more of the initial luminance, and for Light-Emitting Elements 2 and 3, 2 it is maintained at 90% or more. It was found that the light-emitting device has a small decrease in luminance with the accumulation of driving time and has good longevity. As shown in Fig. 20, for Light-Emitting Device 1, which is a light-emitting device of one aspect of the present invention, the luminance at the time when 300 hours have elapsed is 86% or more of the initial luminance, and for Light-Emitting Elements 2 and 3, it is maintained at 90% or more. It was found that the light-emitting device has a small decrease in luminance with the accumulation of driving time and has good longevity. On the other hand, a comparative light-emitting element using cgDBCzPA, which is a material with a high electron mobility of 7.7×10 when the square root of the electric field strength [V / cm] is 600, for the electron transport layer,

[0236] is - 5 cm 2 / Vs, The luminance at the time point of 300 hours has reached 84% or less of the initial luminance in Comparative Light-Emitting Element 1 and 80% or less in Comparative Light-Emitting Element 2. These comparative light-emitting elements have a situation where the electron mobility in the electron transport layer is too high compared to the hole injection and transport capabilities of the hole injection and transport layer of the hole injection and transport layer, so that the light-emitting region in the light-emitting layer becomes narrow, and it is considered that the deterioration is accelerated.

[0237] In addition, in the comparative light-emitting element, cgDBCzPA corresponds to the sixth organic compound and the seventh organic compound, so that there is no difference in the LUMO levels between the sixth organic compound and the seventh organic compound. For this reason, it has a structure in which electrons are more easily injected into the light-emitting layer 113, and a structure in which an electron-excessive state is easily formed.

[0238] Furthermore, in Comparative Light-Emitting Element 2, in addition to the high transportability of the electron transport layer, the difference between the HOMO level of PCBBiF, which is the organic compound used for the first hole transport layer, and the HOMO level of PCzN2, which is used for the second hole transport layer, is 0.36 eV, which is larger than 0.2 eV. This results in a structure where the injection of holes from the first hole transport layer to the second hole transport layer is suppressed in Comparative Light-Emitting Element 2, and it becomes more difficult to balance holes and electrons. As a result, among these elements, it is the light-emitting element with the largest deterioration. Also, compared with other light-emitting elements, Comparative Light-Emitting Element 2 has a lower current efficiency and external quantum efficiency. Therefore, it is considered that the number of electrons that pass through the light-emitting layer without recombining due to an excess of electrons is increasing.

[0239]

Example

[0239] In this example, the light-emitting devices 4 to 6 according to one aspect of the present invention and the light-emitting devices of the comparative example The comparative light-emitting device 3, which is a vice, will be described. Light-emitting devices 4 to 6 , the structural formula of the organic compound used in the comparative light-emitting device 3 is shown below.

[0240] [Chemical formula]

[0241] (Method for manufacturing the light-emitting device 4) First, indium tin oxide (ITSO) containing silicon oxide was sputtered onto a glass substrate by a sputtering method to form the anode 101. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0242] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, and after baking at 2 00 °C for 1 hour, UV ozone treatment was performed for 370 seconds.

[0243] After that, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 -4 Pa, and vacuum baking was performed at 170 °C for 30 minutes in the heating chamber of the vacuum evaporation apparatus. Then, the substrate was allowed to cool for about 30 minutes while cooling.

[0244] Next, with the surface on which the anode 101 was formed facing downward, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus, and on the anode 101, N-(1,1'-biphenyl-4-yl)-9, 9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] -9H-fluorene-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and ALD-MP001Q (manufactured by Analysis Workshop Co., Ltd., material serial number: 1S20170124) were vapor-deposited by a resistance heating vapor deposition method in a weight ratio of 1:0.1 Analysis Workshop Co., Ltd., material serial number: 1S20170124) and ALD-MP001Q (manufactured by ​(=PCBBiF:ALD-MP001Q), 10 nm of co-evaporation was carried out to form a hole injection layer. Layer 111 was formed.

[0245] Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was deposited to a thickness of 20 nm, and then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino- p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was deposited to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0246] Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix), and the above structural formula (iv) N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03 ) were co-evaporated at a weight ratio of 1:0.03 (=αN-βNPAnth:1,6BnfAPrn-03) to a thickness of 25 nm to form a light-emitting layer 113.

[0247] Thereafter, on the light-emitting layer 113, 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2m DBTBPDBq-II) was deposited to a thickness of 15 nm, and then 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (vi) was deposited to a thickness of 10 nm to form an electron transport layer. ​ 114 was formed.

[0248] After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a film thickness of 1 nm to form the electron injection layer 115. Subsequently, aluminum was deposited to a film thickness of 200 nm to form the cathode 102, thereby fabricating the light-emitting device 4 of this example.

[0249] (Fabrication method of light-emitting device 5) The light-emitting device 5 was fabricated in the same manner as the light-emitting device 4, except that PCBBiF in the light-emitting device 4 was changed to N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d] furan-8-amine (abbreviation: BBABnf) represented by the above structural formula (vii).

[0250] (Fabrication method of light-emitting device 6) The light-emitting device 6 was fabricated in the same manner as the light-emitting device 5, except that DBfBB1TP in the light-emitting device 5 was changed to 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviation: PCzN2) represented by the above structural formula (viii).

[0251] (Fabrication method of comparative light-emitting device 3) The comparative light-emitting device 3 was fabricated in the same manner as the light-emitting device 4, except that 2mDBTBPDBq-II in the light-emitting device 4 was changed to αN-βNPAn th.

[0252] The device structures of the light-emitting devices 4 to 6 and the comparative light-emitting device 3 are summarized in the following table.

[0253]

Table 4

[0254] ​ Here, a table summarizing the HOMO level, LUMO level, and electron mobility when the square root of the electric field strength [V / cm] is 600 for the organic compounds used in this example is shown below.

[0255]

Table 5

[0256] These light-emitting devices were sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting devices were not exposed to the atmosphere (applying a sealing material around the element and performing UV treatment and heat treatment at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of these light-emitting devices were measured. The measurements were carried out at room temperature. The luminance-current density characteristics of Light-Emitting Devices 4 to 6 and Comparative Light-Emitting Device 3 are shown in FIG. 21

[0257] , the current efficiency-luminance characteristics are shown in FIG. 22, the luminance-voltage characteristics are shown in FIG. 23, the current-voltage characteristics are shown in FIG. 24, the external quantum efficiency-luminance characteristics are shown in FIG. 25, and the emission spectra are shown in FIG. 26. Also, the main characteristics of each light-emitting device near 1000 cd / m are shown in Table 6. near are shown in Table 6. 2

[0258]

Table 6

[0259] From FIGS. 21 to 26 and Table 6, it was found that all of Light-Emitting Devices 4 to 6, which are one aspect of the present invention, are blue light-emitting devices with good characteristics.

[0260] Also, a graph showing the change in luminance with respect to the driving time at a current density of 50 mA / cm 2 is shown in FIG. as shown in FIG. 27. As shown in FIG. 27, the light-emitting device 4 which is a light-emitting device according to one aspect of the present invention to the light-emitting device 6 maintains about 94% of the initial luminance even at the time when 300 hours have elapsed, and it has been found that the light-emitting device has a small luminance decrease accompanying the accumulation of the driving time and has a good life .

[0261] Since the comparative light-emitting element 3 has αN-βNPAnth corresponding to both the sixth organic compound and the seventh organic compound, there is no difference in the LUMO levels of the sixth organic compound and the seventh organic compound, resulting in a configuration. Therefore, it has a configuration in which electrons are more easily injected into the light-emitting layer 113, and it is considered that a state of excessive electrons is easily formed and the deterioration is promoted .

Example

[0262] In this example, the light-emitting device 7 and the light-emitting device 8 according to one aspect of the present invention will be described . The structural formulas of the organic compounds used in the light-emitting device 7 and the light-emitting device 8 are shown below

[0263]

Chemical formula

[0264] (Method for manufacturing the light-emitting device 7) First, indium tin oxide (ITSO) containing silicon oxide was formed into a film on a glass substrate by a sputtering method to form the anode 101. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm

[0265] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 2 00 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds

[0266] After that, 10​​-4 The substrate was introduced into a vacuum evaporation apparatus whose interior was evacuated to a degree of Pa, and vacuum evaporation was carried out in the heating chamber of the vacuum evaporation apparatus at 170 °C for 30 minutes, and then the substrate was allowed to cool for about 30 minutes.

[0267] Next, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the anode 101 was formed faced downward. On the anode 101, N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf) represented by the above structural formula (vii) and ALD-MP001Q (Analytical Works Co., Ltd., material serial number: 1S20170124) were co-evaporated in a weight ratio of 1:0.1 (=BBABnf:ALD-MP001Q) to form a hole injection layer 111 to a thickness of 10 nm.

[0268] Next, on the hole injection layer 111, as the first hole transport layer 112-1, BBABnf was evaporated to a thickness of 20 nm, and then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino- p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0269] Subsequently, 7-[4-(10-phenyl-9-anthryl )phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA) represented by the above structural formula (iii) and 3,10-bis[N-(9-phenyl-9H-carbazole -2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b’]bisbenzof lan (abbreviation: 3,10PCA2Nbf(IV)-02) in a weight ratio of 1:0.015 (= cgDBCzPA:3,10PCA2Nbf(IV)-02) and co-evaporated at 25 nm to form the light-emitting layer 113.

[0270] Subsequently, on the light-emitting layer 113, 2-[3'-(dibenzothiophen ene-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2m DBTBPDBq-II) was deposited to a thickness of 15 nm, and then the above structural formula (vi) 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-f enanthroline (abbreviation: NBPhen) was deposited to a thickness of 10 nm to form the electron transport layer 114.

[0271] After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm to form the cathode 102, thus fabricating the light-emitting device 7 of this example.

[0272] (Fabrication method of light-emitting device 8) The light-emitting device 8 was fabricated in the same manner as the light-emitting device 7, except that cgDBCzPA in the light-emitting device 7 was changed to 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene ( abbreviation: αN-βNPAnth) represented by the above structural formula (ix).

[0273] The device structures of the light-emitting device 7 and the light-emitting device 8 are summarized in the following table.

[0274]

Table 7

[0275] Here, the following is a table summarizing the HOMO level, LUMO level, and electric field strength of the organic compounds used in this example, and the electron mobility when the square root of [V / cm] is 600.

[0276]

Table 8

[0277] These light-emitting devices were sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting devices were not exposed to the atmosphere (applying a sealing material around the element and performing UV treatment and heat treatment at 80 °C for 1 hour during sealing). After that, the initial characteristics and reliability of these light-emitting devices were measured. The measurements were performed at room temperature. The luminance-current density characteristics of Light-Emitting Device 7 and Light-Emitting Device 8 are shown in Fig. 28, the current efficiency-luminance characteristics are shown in Fig. 29, the luminance-voltage characteristics are shown in Fig. 30, the current-voltage characteristics are shown in Fig. 31, and the external quantum efficiency

[0278] -luminance characteristics are shown in Fig. 32, and the emission spectrum is shown in Fig. 33. Also, the main characteristics of each light-emitting device near 100 0 cd / m 2 are shown in Table 9. From Figs. 28 to 33 and Table 9, it was found that both Light-Emitting Device 7 and Light-Emitting Device

[0279]

Table 9

[0280] 8, which are one aspect of the present invention, are both blue light-emitting devices with good characteristics.

[0281] Also, at a current density of 50 mA / cm​2 A graph showing the change in luminance with respect to the driving time in is shown in FIG. 34. As shown in FIG. 34, the light-emitting device 7 which is a light-emitting device according to one aspect of the present invention and the light-emitting device 8 both maintain a luminance of 90% or more of the initial luminance even at the time when 300 hours have elapsed, and it has been found that they are light-emitting devices with little luminance degradation accompanying the accumulation of driving time and good lifetime.

Example

[0282] In this example, the light-emitting device 9 according to one aspect of the present invention will be described. The structural formula of the organic compound used in the light-emitting device 9 is shown below.

[0283]

Chemical formula

[0284] (Method for manufacturing the light-emitting device 9) First, indium tin oxide (ITSO) containing silicon oxide was formed into a film on a glass substrate by a sputtering method to form the anode 101. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0285] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 2 00 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0286] Thereafter, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 -4 Pa, and vacuum baking was performed at 170 °C for 30 minutes in the heating chamber of the vacuum evaporation apparatus, and then the substrate was allowed to cool for about 30 minutes.

[0287] Next, with the surface on which the anode 101 is formed facing downward, the substrate on which the anode 101 is formed is placed in a vacuum​​​ Fixed to a substrate holder provided inside a vacuum evaporation device, and on the anode 101, by a vapor deposition method using resistance heating, N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf) represented by the above structural formula (vii), and ALD-MP001Q (Analytical Workshop Co., Ltd., material serial number: 1S20170124) were co-evaporated at 10 nm so that the weight ratio was 1:0.1 (= BBABnf:ALD-MP001Q) to form a hole injection layer 111. Next, on the hole injection layer 111, as the first hole transport layer 112-1, BBABnf was vapor-deposited to a thickness of 20 nm, and then, as the second hole transport layer 112-2, 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviation: PCzN2) represented by the above structural formula (vii) was vapor-deposited to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113.

[0288] Next, on the hole injection layer 111, as the first hole transport layer 112-1, BBABnf was vapor-deposited to a thickness of 20 nm, and then, as the second hole transport layer 112-2, 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole) (abbreviation: PCzN2) represented by the above structural formula (vii) was vapor-deposited to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113.

[0289] Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113. Subsequently, 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-evaporated at 25 nm so that the weight ratio was 1:0.015 (= αN-βNPAnth:3,10PCA2Nbf(IV)-02) to form a light-emitting layer 113.

[0290] Subsequently, on the light-emitting layer 113, 2-{4-[9,10-di( naphthalen-2-yl)-2-anthryl]phenyl}-1-phenyl-1H-benzo imidazole (abbreviation: ZADN) and 8-hydroxyquinolinato trilithium (abbreviation: Liq) represented by the above structural formula (xx) were co-evaporated at a weight ratio of 1:0.9 (=ZADN:Liq) to form an electron transport layer 114 with a thickness of 25 nm.

[0291] After forming the electron transport layer 114, Liq was evaporated to a film thickness of 1 nm to form an electron injection layer 1 15, and then aluminum was evaporated to a film thickness of 200 nm to form a cathode 102, and the light-emitting device 9 of this example was fabricated.

[0292] The device structure of the light-emitting device 9 is summarized in the following table.

[0293]

Table 10

[0294] Here, the following table summarizes the HOMO level, LUMO level, and electric field strength of the organic compounds used in this example and the electron mobility when the square root of [V / cm] is 600.

[0295]

Table 11

[0296] This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (applying a sealing material around the device and performing UV treatment and heat treatment at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of the light-emitting device 9 were evaluated. Reliability was measured. The measurement was performed at room temperature.

[0297] The luminance-current density characteristics of the light-emitting device 9 are shown in FIG. 35, the current efficiency-luminance characteristics are shown in FIG. 36, the luminance -voltage characteristics are shown in FIG. 37, the current-voltage characteristics are shown in FIG. 38, and the external quantum efficiency-luminance characteristics are shown in FIG. 39 . The emission spectrum is shown in FIG. 40. Also, near 1000 cd / m 2 of the light-emitting device, the main characteristics are shown in Table 12.

[0298]

Table 12

[0299] From FIGS. 35 to 40 and Table 12, it was found that the light-emitting device 9, which is one aspect of the present invention, is a blue light-emitting device with good characteristics.

[0300] Also, a graph showing the change in luminance with respect to the driving time at a current density of 50 mA / cm 2 is shown in FIG. 41. As shown in FIG. 41, the light-emitting device 9, which is a light-emitting device according to one aspect of the present invention, maintains a luminance of around 90% of the initial luminance even at the time point when 600 hours have elapsed, and it was found that it is a light-emitting device with very little luminance decrease accompanying the accumulation of driving time and very good lifespan.

[0301] Note that it can be seen that the degradation curve of the light-emitting element 9 has an increase in luminance after once experiencing a decrease in luminance. Due to such degradation behavior, the light-emitting element 9 is a light-emitting element with a very long lifespan.

Example

[0302] In this example, a light-emitting device 10 according to one aspect of the present invention will be described. The light-emitting device 10 The structural formula of the organic compound used in [device name] is shown below.

[0303] [Chemical formula]

[0304] (Method for manufacturing the light-emitting device 10) First, indium tin oxide (ITSO) containing silicon oxide was sputter-deposited onto a glass substrate by a sputtering method to form the anode 101. The film thickness was set to 70 nm, and the electrode area was 2 mm × 2 mm.

[0305] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, baked at 200 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0306] After that, the substrate was introduced into a vacuum evaporation apparatus whose internal pressure was reduced to about 10 -4 Pa, and vacuum baking was performed at 170 °C for 30 minutes in the heating chamber of the vacuum evaporation apparatus. Then, the substrate was allowed to cool for about 30 minutes.

[0307] Next, with the surface on which the anode 101 was formed facing downward, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus, and N-(1,1'-biphenyl-4-yl)-9, 9-dimethyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] -9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and ALD-MP001Q (manufactured by Analysis Workshop Co., Ltd., material serial number: 1S20170124) were co-evaporated at a weight ratio of 1:0.1 (=PCBBiF:ALD-MP001Q) to form a 10-nm-thick hole injection layer 111. ​

[0308] Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was deposited to a thickness of 20 nm, and then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino- p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was deposited to a thickness of 10 nm to form the hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0309] Subsequently, 9-(1-naphthyl)-10-[4-(2-naph thyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N- phenylamino]naphtho[2,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,1 0PCA2Nbf(IV)-02) represented by the above structural formula (x) were co-deposited at a weight ratio of 1:0.015 (=αN-βNPAnt h:3,10PCA2Nbf(IV)-02) to a thickness of 25 nm to form the light-emitting layer 1 13.

[0310] Thereafter, 2-[3’-(dibenzothiophen ene-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2m DBTBPDBq-II) represented by the above structural formula (v) was deposited to a thickness of 15 nm, and then 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-f enanthroline (abbreviation: NBPhen) represented by the above structural formula (vi) was deposited to a thickness of 10 nm to form the electron transport layer 114.

[0311] After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a film thickness of 1 nm to form the electron injection layer 115. Subsequently, aluminum was evaporated to a film thickness of 200 nm to form the cathode 102, thereby fabricating the light-emitting device 10 of this example. After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a film thickness of 1 nm to form the electron injection layer 115. Subsequently, aluminum was evaporated to a film thickness of 200 nm to form the cathode 102, thereby fabricating the light-emitting device 10 of this example. After forming the electron transport layer 114, lithium fluoride (LiF) was evaporated to a film thickness of 1 nm to form the electron injection layer 115. Subsequently, aluminum was evaporated to a film thickness of 200 nm to form the cathode 102, thereby fabricating the light-emitting device 10 of this example.

[0312] The element structure of the light-emitting device 10 is summarized in the following table.

[0313]

Table 13

[0314] In addition, the following table summarizes the HOMO level, LUMO level, and electron mobility when the square root of the electric field strength [V / cm] of the organic compound used in this example is 600. In addition, the following table summarizes the HOMO level, LUMO level, and electron mobility when the square root of the electric field strength [V / cm] of the organic compound used in this example is 600.

[0315]

Table 14

[0316] This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (a sealing material was applied around the element, and UV treatment and heat treatment were performed at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of the light-emitting device 10 were measured. The measurements were performed at room temperature. This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (a sealing material was applied around the element, and UV treatment and heat treatment were performed at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of the light-emitting device 10 were measured. The measurements were performed at room temperature. This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (a sealing material was applied around the element, and UV treatment and heat treatment were performed at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of the light-emitting device 10 were measured. The measurements were performed at room temperature. This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (a sealing material was applied around the element, and UV treatment and heat treatment were performed at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of the light-emitting device 10 were measured. The measurements were performed at room temperature.

[0317] The luminance-current density characteristics of the light-emitting device 10 are shown in Fig. 47, the current efficiency-luminance characteristics are shown in Fig. 48, the luminance-voltage characteristics are shown in Fig. 49, the current-voltage characteristics are shown in Fig. 50, the external quantum efficiency-luminance characteristics are shown in Fig. 51, and the emission spectrum is shown in Fig. 52. In addition, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 15. The luminance-current density characteristics of the light-emitting device 10 are shown in Fig. 47, the current efficiency-luminance characteristics are shown in Fig. 48, the luminance-voltage characteristics are shown in Fig. 49, the current-voltage characteristics are shown in Fig. 50, the external quantum efficiency-luminance characteristics are shown in Fig. 51, and the emission spectrum is shown in Fig. 52. In addition, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 15. The luminance-current density characteristics of the light-emitting device 10 are shown in Fig. 47, the current efficiency-luminance characteristics are shown in Fig. 48, the luminance-voltage characteristics are shown in Fig. 49, the current-voltage characteristics are shown in Fig. 50, the external quantum efficiency-luminance characteristics are shown in Fig. 51, and the emission spectrum is shown in Fig. 52. In addition, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 15. 2 near The luminance-current density characteristics of the light-emitting device 10 are shown in Fig. 47, the current efficiency-luminance characteristics are shown in Fig. 48, the luminance-voltage characteristics are shown in Fig. 49, the current-voltage characteristics are shown in Fig. 50, the external quantum efficiency-luminance characteristics are shown in Fig. 51, and the emission spectrum is shown in Fig. 52. In addition, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 15.

[0318]

Table 15

[0319] From FIGS. 47 to 52 and Table 15, it was found that the light-emitting device 10, which is one embodiment of the present invention, is a blue light-emitting device with good characteristics. It was found that the light-emitting device 10, which is one embodiment of the present invention, is a blue light-emitting device with good characteristics.

[0320] Also, a graph showing the change in luminance with respect to the driving time at a current density of 50 mA / cm 2 is shown in FIG. 53. As shown in FIG. 53, the light-emitting device 1 0, which is a light-emitting device according to one embodiment of the present invention, maintains a luminance of about 90% of the initial luminance at the time point when 600 hours have elapsed, and it was found that the light-emitting device has a small decrease in luminance with the accumulation of driving time and good lifetime characteristics. It was found that the light-emitting device has a small decrease in luminance with the accumulation of driving time and good lifetime characteristics.

Example

[0321] In this example, the light-emitting device 11 according to one embodiment of the present invention will be described. The structural formula of the organic compound used in the light-emitting device 11 is shown below.

[0322]

Chemical formula

[0323] (Method for manufacturing the light-emitting device 11) First, indium tin oxide (ITSO) containing silicon oxide was formed on a glass substrate by sputtering to form the anode 101. The film thickness was 70 nm, and the electrode area was 2 mm × 2 mm.

[0324] Next, as a pretreatment for forming the light-emitting device on the substrate, the substrate surface was washed with water, baked at 2 00 °C for 1 hour, and then subjected to UV ozone treatment for 370 seconds.

[0325] Subsequently, 10 -4 The substrate was introduced into a vacuum evaporation apparatus whose interior was evacuated to about 10 Pa, and vacuum baking was performed at 170° C. for 30 minutes in the heating chamber of the vacuum evaporation apparatus. Then, the substrate was allowed to cool for about 30 minutes. Subsequently, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the anode 101 was formed faced downward. Onto the anode 101, N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and ALD-MP001Q (Analytical Workshop Co., Ltd., material serial number: 1S20170124) were co-evaporated at a weight ratio of 1:0.1 (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm.

[0326] Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Subsequently, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus so that the surface on which the anode 101 was formed faced downward. Onto the anode 101, N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and ALD-MP001Q (Analytical Workshop Co., Ltd., material serial number: 1S20170124) were co-evaporated at a weight ratio of 1:0.1 (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm. (=PCBBiF:ALD-MP001Q) to form a hole injection layer 111 by co-evaporating 10 nm.

[0327] Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer. Next, on the hole injection layer 111, as the first hole transport layer 112-1, PCBBiF was evaporated to a thickness of 20 nm. Then, as the second hole transport layer 112-2, N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP) represented by the above structural formula (ii) was evaporated to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0328] Subsequently, 7-[4-(10-phenyl-9-anthryl )Phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), and 3,10-bis[N-(9-phenyl-9H-carbazole -2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b’]bisbenzof uran (abbreviation: 3,10PCA2Nbf(IV)-02) were co-evaporated at a weight ratio of 1:0.015 (= cgDBCzPA:3,10PCA2Nbf(IV)-02) to form the light-emitting layer 113 with a thickness of 25 nm.

[0329] Thereafter, 2-[3’-(dibenzothiophen -4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2m DBTBPDBq-II) was deposited to a thickness of 15 nm, and then 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-f enanthroline (abbreviation: NBPhen) represented by the above structural formula (vi) was deposited to a thickness of 10 nm to form the electron transport layer 114.

[0330] After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form the electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm to form the cathode 102, thereby fabricating the light-emitting device 11 of this example.

[0331] The device structure of the light-emitting device 11 is summarized in the following table.

[0332]

Table 16

[0333] ​​​In addition, Table 17 below summarizes the electron mobility when the square root of the HOMO level, LUMO level, and electric field strength [V / cm] of the organic compound used in this example is 600.

[0334]

Table 17

[0335] This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (a sealing material was applied around the element, and UV treatment and heat treatment were performed at 80°C for 1 hour during sealing). After that, the initial characteristics and reliability of the light-emitting device 11 were measured. The measurements were performed at room temperature. The luminance-current density characteristics of the light-emitting device 11 are shown in FIG. 54, the current efficiency-luminance characteristics are shown in FIG. 55, the luminance-voltage characteristics are shown in FIG. 56, the current-voltage characteristics are shown in FIG. 57, the external quantum efficiency-luminance characteristics are shown in FIG. 58

[0336]

[0337] 2 near 1000 cd / m of the light-emitting device are shown in Table 18.

Table 18

[0338]

[0339] From FIGS. 54 to 59 and Table 18, it was found that the light-emitting device 11, which is one aspect of the present invention, is a blue light-emitting device with good characteristics.

[0339] 2 In addition, a graph showing the change in luminance with respect to the driving time at a current density of 50 mA / cm is shown in FIG. 60. As shown in FIG. 60, the light-emitting device 1, which is one aspect of the light-emitting device of the present invention 1 maintains 80% or more of the initial brightness after 600 hours of operation. It was found that the decrease in luminance due to the increase in the charge was small, and that the device had a long life. EXAMPLES

[0340] In this example, a light-emitting device 12 according to one embodiment of the present invention will be described. The structural formulas of the organic compounds used are shown below.

[0341] [ka]

[0342] (Method of Making Light-Emitting Device 12) First, indium tin oxide containing silicon oxide (ITSO) was sputtered onto a glass substrate. The anode 101 was formed by a film deposition method. The film thickness was set to 70 nm, and the electrode area was 2 The dimensions were 2 mm x 2 mm.

[0343] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, and then After baking at 00°C for 1 hour, UV ozone treatment was performed for 370 seconds.

[0344] Then, 10 -4 The substrate is placed in a vacuum deposition apparatus whose inside has been reduced in pressure to about Pa, and vacuum deposition is performed. After vacuum baking at 170°C for 30 minutes in the heating chamber of the device, the substrate is left for about 30 minutes. Allow to cool.

[0345] Next, the substrate on which the anode 101 is formed is placed in a vacuum so that the surface on which the anode 101 is formed faces downward. The substrate was fixed to a substrate holder installed in the vacuum evaporation apparatus, and evaporation was performed on the anode 101 using resistance heating. The N,N-bis(4-biphenyl)-6-phenylene represented by the above structural formula (vii) was obtained by the above method. Nilbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), and ALD-MP001Q (Analytical Works Co., Ltd., material serial number: 1S20170124) were co-evaporated at a weight ratio of 1:0.1 (= BBABnf:ALD-MP001Q) to form a hole injection layer 111 with a thickness of 1 0 nm.

[0346] Next, on the hole injection layer 111, as the first hole transport layer 112-1, BBABnf was evaporated to a thickness of 20 nm, and then, as the second hole transport layer 112-2, 3,3’-(naphthalene-1,4-diyl)bis(9-phenyl-9H- carbazole) (abbreviation: PCzN2) represented by the above structural formula (vii i) was evaporated to a thickness of 10 nm to form a hole transport layer 112 . Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0347] Subsequently, 9-(1-naphthyl)-10-[4-(2-naph thyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix) and the above structural formula (x) 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-p henylamino]naphtho[2,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,10 PCA2Nbf(IV)-02) were co-evaporated at a weight ratio of 1:0.015 (= αN-βNPAnth :3,10PCA2Nbf(IV)-02) to a thickness of 25 nm to form a light-emitting layer 11 3.

[0348] Thereafter, on the light-emitting layer 113, 2-[3’-(dibenzothiophen en-4-yl)biphenyl-3-yl]dibenz[f,h]quinoxaline (abbreviation: 2m After depositing DBTBPDBq-II) to a film thickness of 15 nm, the above structural formula (vi) 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-f enanthroline (abbreviation: NBPhen) was deposited to a film thickness of 10 nm to form an electron transport layer 114.

[0349] After forming the electron transport layer 114, LiF was deposited to a film thickness of 1 nm to form an electron injection layer 1 15, and then aluminum was deposited to a film thickness of 200 nm to form a cathode 102, and the light-emitting device 12 of this example was fabricated.

[0350] The device structure of the light-emitting device 12 is summarized in the following table.

[0351]

Table 19

[0352] Here, a table summarizing the HOMO level, LUMO level, and electron mobility of the organic compound used in this example when the square root of the electric field strength [V / cm] is 600 is shown below.

[0353]

Table 20

[0354] This light-emitting device was sealed with a glass substrate in a glove box under a nitrogen atmosphere so that the light-emitting device was not exposed to the atmosphere (a sealing material was applied around the device, and UV treatment and heat treatment at 80 °C for 1 hour were performed during sealing). After that, the initial characteristics and reliability of the light-emitting device 12 were measured. The measurements were performed at room temperature. Note that the measurements were performed at room temperature.

[0355] The luminance-current density characteristics of the light-emitting device 12 are shown in FIG. 61, the current efficiency-luminance characteristics are shown in FIG. 62, the luminance-voltage characteristics are shown in FIG. 63, the current-voltage characteristics are shown in FIG. 64, the external quantum efficiency-luminance characteristics are shown in FIG. 65, and the emission spectrum is shown in FIG. 66. Also, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 21. The luminance-voltage characteristics are shown in FIG. 63, the current-voltage characteristics are shown in FIG. 64, the external quantum efficiency-luminance characteristics are shown in FIG. 65, and the emission spectrum is shown in FIG. 66. Also, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 21. The luminance-current density characteristics of the light-emitting device 12 are shown in FIG. 61, the current efficiency-luminance characteristics are shown in FIG. 62, the luminance-voltage characteristics are shown in FIG. 63, the current-voltage characteristics are shown in FIG. 64, the external quantum efficiency-luminance characteristics are shown in FIG. 65, and the emission spectrum is shown in FIG. 66. Also, the main characteristics of the light-emitting device around 1000 cd / m² are shown in Table 21. 2 near are shown in Table 21.

[0356]

Table 21

[0357] From FIGS. 61 to 66 and Table 21, it was found that the light-emitting device 12, which is one aspect of the present invention, is a blue light-emitting device with good characteristics. It was found that the light-emitting device 12, which is one aspect of the present invention, is a blue light-emitting device with good characteristics.

[0358] 2 Also, a graph showing the change in luminance with respect to the driving time at a current density of 50 mA / cm² is shown in FIG. 67. As shown in FIG. 67, the light-emitting device 12, which is a light-emitting device according to one aspect of the present invention, maintains a luminance of 90% or more of the initial luminance even at the time point when 600 hours have elapsed, and it was found that the light-emitting device has a particularly small decrease in luminance with the accumulation of driving time and has very good durability. It was found that the light-emitting device 12, which is a light-emitting device according to one aspect of the present invention, maintains a luminance of 90% or more of the initial luminance even at the time point when 600 hours have elapsed, and it was found that the light-emitting device has a particularly small decrease in luminance with the accumulation of driving time and has very good durability. It was found that the light-emitting device has a particularly small decrease in luminance with the accumulation of driving time and has very good durability.

Example

[0359] In this example, the light-emitting devices 13 to 20 according to one aspect of the present invention will be described. The structural formulas of the organic compounds used in the light-emitting devices 13 to 20 are shown below. In this example, the light-emitting devices 13 to 20 according to one aspect of the present invention will be described. The structural formulas of the organic compounds used in the light-emitting devices 13 to 20 are shown below.

[0360]

Chemical formula

[0361]

Chemical formula

[0362] (Method for manufacturing the light-emitting device 13) First, indium tin oxide (ITSO) containing silicon oxide was sputter-deposited onto a glass substrate by a sputtering method to form the anode 101. The film thickness was set to 70 nm, and the electrode area was 2 mm × 2 mm.

[0363] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water, and after baking at 2 00 °C for 1 hour, UV ozone treatment was performed for 370 seconds.

[0364] Thereafter, the substrate was introduced into a vacuum evaporation apparatus whose interior was evacuated to about 10 -4 Pa, and vacuum baking was performed at 170 °C for 30 minutes in the heating chamber of the vacuum evaporation apparatus. Then, the substrate was allowed to cool for about 30 minutes.

[0365] Next, with the surface on which the anode 101 was formed facing downward, the substrate on which the anode 101 was formed was fixed to a substrate holder provided in the vacuum evaporation apparatus, and 4-(6;2'-binaphthyl-2-yl)- represented by the above structural formula (xii) was vapor-deposited onto the anode 101 by a vapor deposition method using resistance heating. 4',4''-diphenyltriphenylamine (abbreviation: BBA(βN2)B) and ALD -MP001Q (Analytical Factory Co., Ltd., material serial number: 1S20170124) were co-evaporated at a weight ratio of 1:0.1 (= BBA(βN2)B:ALD-MP001Q) to form a hole injection layer 111. 0 nm.

[0366] Next, BBA(βN2)B was vapor-deposited onto the hole injection layer 111 to a thickness of 20 nm as the first hole transport layer 112-1. Then, as the second hole transport layer 112-2, the above structural formula ( viii) represented by 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl- 9H-carbazole) (abbreviation: PCzN2) was deposited to a thickness of 10 nm to form a hole transport layer 112. Note that the second hole transport layer 112-2 also functions as an electron blocking layer.

[0367] Subsequently, 9-(1-naphthyl)-10-[4-(2-naph thyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (ix), and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N- phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,1 0PCA2Nbf(IV)-02) were co-deposited at a weight ratio of 1:0.015 (=αN-βNPAnt h:3,10PCA2Nbf(IV)-02) to a thickness of 25 nm to form a light-emitting layer 1 13.

[0368] Thereafter, 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2m DBTBPDBq-II) represented by the above structural formula (v) was deposited to a film thickness of 15 nm, and then 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) represented by the above structural formula (vi) was deposited to a film thickness of 10 nm to form an electron transport layer 114. After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a film thickness of 1 nm to form an electron injection layer 115, and then aluminum was deposited to a film thickness of 200 nm

[0369] After forming the electron transport layer 114, lithium fluoride (LiF) was deposited to a thickness of 1 nm to form an electron injection layer 115, and then aluminum was deposited to a thickness of 200 nm ​​​The cathode 102 was formed by evaporation to fabricate the light-emitting device 13 of this example.

[0370] (Method for fabricating the light-emitting device 14) The light-emitting device 14 was fabricated in the same manner as the light-emitting device 13, except that BBA(βN2)B in the light-emitting device 13 was changed to 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9 H-fluoren-9-yl)triphenylamine (abbreviation: FLPAPA) represented by the above structural formula (xi ii).

[0371] (Method for fabricating the light-emitting device 15) The light-emitting device 15 was fabricated in the same manner as the light-emitting device 13, except that BBA(βN2)B in the light-emitting device 13 was changed to N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1, 2-d]furan-8-amine (abbreviation: BnfABP) represented by the above structural formula (xi v).

[0372] (Method for fabricating the light-emitting device 16) The light-emitting device 16 was fabricated in the same manner as the light-emitting device 13, except that BBA(βN2)B in the light-emitting device 13 was changed to 4-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]-4 ’,4’’-diphenyltriphenylamine (abbreviation: mpBBAFLBi) represented by the above structural formula (xv ).

[0373] (Method for fabricating the light-emitting device 17) The light-emitting device 17 was fabricated in the same manner as the light-emitting device 13, except that BBA(βN2)B in the light-emitting device 13 was changed to N-[4-(9H-carbazol-9-yl)phenyl]-N-(1,1 ’-biphenyl-2-yl)-9,9’-spirobi[9H-fluorene]-2-amine ( ) represented by the above structural formula (xv ​​​It was fabricated in the same manner as the light-emitting device 13, except that the abbreviation was changed to oYGBiSF).

[0374] (Fabrication method of the light-emitting device 18) The light-emitting device 18 is obtained by changing BBA(βN2)B in the light-emitting device 13 to 4-(4-biphenylyl)-4’-[4-(2-naphthyl)phenyl] -4’’-phenyltriphenylamine (abbreviation: TPBiAβNBi) represented by the above structural formula (xv and fabricating it in the same manner as the light-emitting device 13.

[0375] (Fabrication method of the light-emitting device 19) The light-emitting device 19 is obtained by changing BBA(βN2)B in the light-emitting device 13 to 4,4’-diphenyl-4’’-(7;1’-binaphthyl-2-yl )triphenylamine (abbreviation: BBAαNβNB-03) represented by the above structural formula (xv ) and fabricating it in the same manner as the light-emitting device 13

[0376] (Fabrication method of the light-emitting device 20) The light-emitting device 20 is obtained by changing BBA(βN2)B in the light-emitting device 13 to 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]- 4’,4’’-diphenyltriphenylamine (abbreviation: BBAFLBi) represented by the above structural formula (xi x) and fabricating it in the same manner as the light-emitting device 13

[0377] The device structures of the light-emitting devices 13 to 20 are summarized in the following table.

[0378]

Table 22

[0379] In addition, the HOMO level, LUMO level, and electric field strength of the organic compounds used in this example [V​​​ The table below summarizes the electron mobility when the square root of [N / cm] is 600.

[0380] [Table 23]

[0381] These light-emitting devices were placed in a nitrogen-atmosphere glove box, and the light-emitting devices were placed in a nitrogen-atmosphere glove box. The process of sealing the element with a glass substrate to prevent it from being exposed to heat (sealing material is applied around the element and sealed After performing UV treatment at the time of shutdown and heat treatment at 80°C for 1 hour, the initial characteristics of these light-emitting devices were The reliability and reliability were measured at room temperature.

[0382] FIG. 68 shows the luminance vs. current density characteristics of the light-emitting devices 13 to 20. The luminance characteristics are shown in Fig. 69, the luminance-voltage characteristics in Fig. 70, the current-voltage characteristics in Fig. 71, and the external quantum efficiency The efficiency-luminance characteristics are shown in FIG. 72, and the emission spectrum is shown in FIG. 73. 00cd / m 2 The main characteristics of the area are shown in Table 24. The numbers in the graph legend are Each number corresponds to a light-emitting device.

[0383] [Table 24]

[0384] 68 to 73 and Table 24, the light-emitting devices 13 to 15 according to the embodiments of the present invention are It was found that all of the devices 20 were blue light-emitting devices with good characteristics.

[0385] In addition, the current density is 50mA / cm 2 The graph shows the change in brightness with respect to the operating time. as shown in FIG. 74. As shown in FIG. 74, the light-emitting device 1 which is a light-emitting device according to one aspect of the present invention 3 to 20 all maintain a luminance of 90% or more of the initial luminance at the time when 300 hours have elapsed, particularly the light-emitting element 14 maintains a luminance of 95% or more, has a small luminance decrease with the accumulation of the driving time, and is found to be a light-emitting device with good lifespan

[0386] <Reference Example 1> In this reference example, the calculation methods of the HOMO level, LUMO level, and electron mobility of the organic compounds used in each example will be described

[0387] The HOMO level and LUMO level can be calculated based on cyclic voltammetry (CV) measurement

[0388] As the measuring device, an electrochemical analyzer (manufactured by BAS Inc., model number: ALS model 600A or 600C) was used. The solution in the CV measurement used dehydrated dimethyl formamide (DMF) (manufactured by Aldrich Co., Ltd., 99.8%, catalog number; 227 05-6) as the solvent, and tetra-n-butylammonium perchlorate (n-B u4NClO4) (manufactured by Tokyo Chemical Industry Co., Ltd., catalog number; T0836) was dissolved to a concentration of 100 mmol / L, and the measurement target was further dissolved to a concentration of 2 mmol / L to prepare. As the working electrode, a platinum electrode (manufactured by BAS Inc., PT E platinum electrode) was used, a platinum electrode (manufactured by BAS Inc., VC-3 used P t counter electrode (5 cm)) was used as the auxiliary electrode, and an Ag / Ag + electrode (manufactured by BAS Inc., RE7 non-aqueous solvent-based reference electrode) was used as the reference electrode. The measurement was performed at room temperature (20~ ​​​​It was carried out at 25°C. Also, the scan rate during CV measurement was unified to 0.1 V / sec, and the oxidation potential Ea [V] and reduction potential Ec [V] with respect to the reference electrode were measured. Ea was taken as the intermediate potential of the oxidation-reduction wave, and Ec was taken as the intermediate potential of the reduction-oxidation wave. Here, since the potential energy with respect to the vacuum level of the reference electrode used in this example is -4.94 [eV], the HOMO level [eV] = -4.94 - Ea and the LUMO level [eV] = -4.94 - Ec, and the HOMO level and LUMO level can be obtained respectively from these equations.

[0389] The electron mobility can be measured by impedance spectroscopy (IS method).

[0390] For the measurement of the carrier mobility of the EL material, methods such as the time-of-flight (TOF) method and the method of obtaining it from the I-V characteristics of space-charge-limited current (SCLC) (SCLC method) have been known for a long time. The TOF method requires a sample with a considerably thick film thickness compared to an actual organic EL element. The SCLC method has drawbacks such as not being able to obtain the electric field strength dependence of the carrier mobility. In the IS method, since the film thickness of the organic film required for measurement is as thin as about several hundred nm, it is possible to form a film even with a relatively small amount of EL material, and it is characteristic that the mobility can be measured at a film thickness close to that of an actual EL element, and the electric field strength dependence of the carrier mobility can also be obtained.

[0391] In the IS method, a small sinusoidal voltage signal (V = V0[exp(jωt)]) is applied to the EL element, The amplitude of the response current signal (I = I0exp[j(ωt+φ)]) and its phase with the input signal The impedance of the EL element (Z=V / I) is calculated from the difference. If the applied voltage is varied from 0.01 to 0.1 V, the impedance will vary with the relaxation time. The components can be separated and measured.

[0392] Here, the admittance Y (= 1 / Z), which is the reciprocal of the impedance, is given by the following formula (1): It can be expressed as conductance G and susceptance B as shown below.

[0393]

number

[0394] Furthermore, by using the single charge injection model, The following equations (2) and (3) can be calculated: where g (equation (4)) is the differential conductance. In the formula, C is the capacitance, θ is the travel angle, and ω represents the angular frequency. t is the transit time. The analysis uses the current equation, Poisson's equation, and current continuity equation. The above equation is used, ignoring the existence of diffusion current and trap levels.

[0395]

number

[0396] The method of calculating the mobility from the frequency characteristics of the capacitance is the -ΔB method. The ωΔG method is a method for calculating the mobility from the frequency characteristics of a carrier.

[0397] In practice, first, an electron-only device is fabricated from the material whose electron mobility is to be determined. - An element is an element designed so that only electrons flow as carriers. In this specification a method (-ΔB method) for calculating mobility from the frequency characteristics of capacitance will be described. The schematic diagram of the electron-only device used is shown in Fig. 42.

[0398] This time, the structure of the electron-only device fabricated for measurement has a first layer 210, a second layer 211, and a third layer 212 between the anode 201 and the cathode 202 as shown in Fig. 42. The material for which the electron mobility is to be obtained may be used as the material of the second layer 211. This time, an example of measuring the electron mobility of a co-evaporated film of ZADN and Li q at a 1:1 (weight ratio) will be described. The specific configuration examples are summarized in the following table.

[0399]

Table 25

[0400] The current density-voltage characteristics of the electron-only device fabricated with the co-evaporated film of ZADN and Liq as the second layer 211 are shown in Fig. 43.

[0401] For impedance measurement, while applying a DC voltage in the range of 5.0 V to 9.0 V, the measurement was performed under the conditions that the AC voltage was 70 mV and the frequency was 1 Hz to 3 MHz. The capacitance is calculated from the admittance (the aforementioned equation (1)), which is the reciprocal of the impedance obtained here. The frequency characteristics of the calculated capacitance C at an applied voltage of 7.0 V are shown in Fig. 44.

[0402] The frequency characteristics of the capacitance C are obtained because the space charge due to the carriers injected by the minute voltage signal cannot completely follow the minute AC voltage, resulting in a phase difference in the current. Here, the transit time of the carrier in the film is the time T for the injected carrier to reach the counter electrode. It is defined and expressed by the following equation (5).

[0403]

Equation

[0404] The negative susceptance change (-ΔB) corresponds to the value (-ωΔ C) obtained by multiplying the capacitance change -ΔC by the angular frequency ω. The lowest-frequency peak frequency f’ max (=ω max / 2π) and the transit time T have the relationship of the following equation (6) derived from equation (3). It is derived that there is the following relationship in equation (6) from equation (3) between the transit time T and the lowest-frequency peak frequency f’

[0405]

Equation

[0406] The frequency characteristics of -ΔB calculated from the above measurement (i.e., when the DC voltage is 7.0 V) are shown in Fig. 4 5. The lowest-frequency peak frequency f’ max obtained from Fig. 45 is indicated by the arrow in the figure .

[0407] From f’ max obtained from the above measurement and analysis, the transit time T can be obtained (refer to the above equation ( 6)). Therefore, the electron mobility at a DC voltage of 7.0 V in this case can be obtained from the above equation (5). By performing the same measurement in the range of DC voltages from 5.0 V to 9.0 V, the electron mobility at each voltage (electric field strength) can be calculated, and thus the dependence of the mobility on the electric field strength can also be measured .

[0408] By the above calculation method, the dependence of the finally obtained electron mobility of each organic compound on the electric field strength The property is shown in Fig. 46, and Table 26 shows the values of electron mobility when the square root of the electric field strength [V / cm] read from the figure is 600 [V / cm]. 1 / 2 respectively.

[0409]

Table 26

[0410] As described above, it is possible to calculate the electron mobility. For the detailed measurement method, see , Takayuki Okachi et al. ”Japanese Journal of Applied Physics” Vol. 47, No. 12, 2008,[[]] pp. 8965 - 8972.

[0411] <Reference Example 2>[[]] In this reference example, the synthesis method of the organic compound used in the example will be described.[[]]

[0412] ≪Synthesis Example 1: Synthesis method of 4 - [3 - (9 - phenyl - 9H - fluoren - 9 - yl)phenyl] - 4 ’,4’’ - diphenyltriphenylamine (abbreviation: mpBBAFLBi)≫[[]] The structural formula of mpBBAFLBi is shown below.[[]]

[0413]

Chemical formula

[0414] 2.0 g (5.0 mmol) of 9 - (3 - bromophenyl) - 9 - phenyl - 9H - fluo rene, 2.6 g (5.[[]] 0 mmol) of 2 - {4 - [di(4 - biphenylyl)amino]phen nyl} - 4,4,5,5 - tetramethyl - 1,3,2 - dioxaborolane, 30 mg (0.10 mmol) of tri(ortho - tolyl)phosphine, and carbonic acid 2.8 g (20 mmol) of potassium was added, and the inside of the flask was purged with nitrogen. To this mixture, 15 mL of toluene, 10 mL of ethanol, and 10 mL of water were added, and the mixture was degassed by stirring under reduced pressure. 11 mg (0.050 mmol) of palladium(II) acetate was added to this mixture, and the mixture was stirred at 80 °C for 2 hours under a nitrogen stream. After stirring, the mixture was suction filtered to recover the solid. This solid was dissolved in hot toluene and suction filtered through celite, alumina, and florisil. The solid obtained by concentrating the filtrate was recrystallized from toluene to obtain 2.7 g of the desired white solid in a yield of 74%. The synthetic scheme of the above synthesis method is shown below.

[0415] The synthetic scheme of the above synthesis method is shown below.

[0416]

Chemical formula

[0417] 2.6 g of the obtained white solid was purified by sublimation using the train sublimation method. The sublimation purification was carried out by heating the white solid at 280 °C under the conditions of a pressure of 3.5 Pa and an argon flow rate of 5.0 mL / min. After sublimation purification, 2.3 g of a pale yellow solid was obtained with a recovery rate of 88%.

[0418] The analysis results of the obtained pale yellow solid by nuclear magnetic resonance spectroscopy ( 1 1H NMR) are shown below. From these results, it was confirmed that mpBBAFLBi was obtained. 1 1H NMR (DMSO, 300 MHz): δ = 7.06 - 7.49 (m, 29H), 7 .59 - 7.64 (m, 8H), 7.90 (d, J = 7.8 Hz, 2H).

[0419] ​​​​​​≪Synthesis Example 2: Synthesis of 4-(4-biphenylyl)-4’-[4-(2-naphthyl)phenyl]-4 ’’-phenyltriphenylamine (abbreviation: TPBiAβNBi)≫ The structural formula of TPBiAβNBi is shown below.

[0420]

Chemical formula

[0421] <Step 1: Synthesis of N-(1,1’-biphenyl)-4-yl-(1,1’:4’,1’’- terphenyl)-4-4-amine> 2.4 g (7.4 mmol) of N-(4-bromophenyl)-4-biphenylamine and, 1.5 g (7.4 mmol) of 4-biphenylboronic acid, 47 mg (0.15 mmol ) of tri(ortho-tolyl)phosphine, 7 mL of aqueous potassium carbonate solution (2.0 mol / L), 60 mL of toluene, and 20 mL of ethanol were placed in a 200 mL three-necked flask equipped with a reflux condenser. After degassing the mixture under reduced pressure, the system was purged with nitrogen. To the resulting mixture , 16 mg (74 μmol) of palladium(II) acetate was added and the mixture was refluxed for 3 hours. After stirring , the precipitated solid was collected by suction filtration, and the obtained solid was washed with toluene, ethanol, and water . As a result, 2.94 g of the target gray solid was obtained in a yield of 99% or more. The synthesis scheme of Step 1 is shown below.

[0422]

Chemical formula

[0423] <Step 2: Synthesis of 2-(4-chloro-biphenyl-4-yl)naphthalene> 2.4 g (10 mmol) of 1-chloro-4-iodobenzene and 2.5 g (10 mmo 4-(2-Naphthyl)phenylboronic acid of l) and 61 mg (0.20 mmol) of tri (ortho-Tolyl)phosphine, 20 mL of aqueous potassium carbonate solution (2.0 mol / L) , 70 mL of toluene, and 30 mL of ethanol were placed in a 200 mL three-necked flask equipped with a reflux tube . After degassing the solvent under reduced pressure, the inside was purged with nitrogen. After heating to 60 °C, acetic palladium(II) 22 mg (0.10 mmol) was added, and the mixture was stirred at 50 °C for 3 hours to cause a reaction. After stirring, the precipitated solid was collected by suction filtration and washed with toluene, water, and ethanol . As a result, 2.7 g of a brown solid was obtained in a yield of 86%. The synthesis scheme of Step 2 is shown below .

[0424] [Chemical formula]

[0425] The analysis results of the obtained brown solid by nuclear magnetic resonance spectroscopy( 1 1H NMR) are shown below. From this, it was found that 2-(4-chloro-biphenyl-4-yl)naphtha lene was obtained by the above synthesis step . 1 1H NMR (Dichloromethane-d2, 500 MHz): δ = 8.13 (s, 1H), 7 .96 (d, J = 9.5 Hz, 1H), 7.94 (d, J = 9.5 Hz, 1H), 7.8 9 (d, J = 7.0 Hz, 1H), 7.85 - 7.81 (m, 3H), 7.72 (d, J = 8.0 Hz, 2H), 7.64 (d, J = 8.5 Hz, 2H), 7.55 - 7.49( m, 2H), 7.46 (d, J = 8.0 Hz, 2H).

[0426] [Step 3: 4-(4-Biphenylyl)-4'-[4-(2-naphthyl)phenyl]- Synthesis of 4’’-phenyltriphenylamine (abbreviation: TPBiAβNBi)> 2.94 g (7.4 mmol) of N-(1,1'-biphenyl)- 4-yl-(1,1':4',1''-terphenyl)-4-4-amine obtained in Step 1, and Step 2 2.32 g (7.4 mmol) of 2-(4-chloro-biphenyl-4-yl) naphthalene obtained in, 52 mg (0.15 mmol) of di-tert-butyl (1-methyl-2 ,2-diphenylcyclopropyl)phosphine (trade name: cBRIDP (registered trademark)) and , 1.4 g (15 mmol) of sodium tert-butoxide, and 140 mL of xylene were placed in a 200 mL three-necked flask equipped with a reflux condenser. After degassing the mixture under reduced pressure, the system was purged with nitrogen. To the resulting mixture, 43 mg (74 μmol) of bis(dibenzylidene acetone)palladium(0) was added and refluxed for 5 hours. After stirring, the precipitated solid was collected by suction filtration and washed with toluene, water, and ethanol to obtain 3.8 g of a gray solid . The synthesis scheme of Step 3 is shown below.

[0427]

Chemical formula

[0428] The obtained 3.8 g of solid was purified by sublimation using the train sublimation method. The sublimation purification was performed by heating the solid at 335 °C for 15 hours under a pressure of 3.8 Pa while flowing argon at 15 mL / min . After sublimation purification, 2.8 g of a pale yellow solid of the target product was obtained with a recovery rate of 74%.

[0429] The analysis results of the obtained solid by nuclear magnetic resonance spectroscopy( 1 H NMR) are shown below. To this Thus, in this synthesis example, it was found that TPBiAβNBi was obtained. 1 1H NMR (chloroform-d, 500 MHz): δ = 8.10 (d, J = 1.5 Hz , 1H), 7.94 (d, J = 9.0 Hz, 1H), 7.92 (d, J = 7.5 Hz, 1 H), 7.88 (d, J = 7.5 Hz, 1H), 7.82 - 7.80 (m, 3H), 7. 73 (d, J = 8.5 Hz, 2H), 7.68 (s, 4H), 7.66 (d, J = 7.0 Hz, 2H), 7.62 - 7.58 (m, 6H), 7.55 (d, J = 8.5 Hz, 2H ), 7.52 - 7.43 (m, 6H), 7.36 (t, J = 7.0 Hz, 1H), 7.3 3 (t, J = 7.0 Hz, 1H), 7.29 - 7.27 (m, 6H).

[0430] ≪Synthesis Example 3: Synthesis method of 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-4 ’,4’’-diphenyltriphenylamine (abbreviation: BBAFLBi)≫ The structural formula of BBAFLBi is shown below.

[0431]

Chemical formula

[0432] <Step 1: Synthesis of 4-(9-phenyl-9H-fluoren-9-yl)phenylboronic acid > Into a 500 mL three-necked flask, 15.89 g (40 mmol) of 9-(4-bromophenyl)-9-phenyl-9H-fluorene was placed, and then degassed by reducing the pressure, and the inside of the flask was purged with nitrogen. 200 mL of dehydrated tetrahydrofuran (abbreviation: THF) was added to this container. After cooling this mixture to about -78 °C while stirring, 1.59 mol / mL of a certain reagent (not specified in the original) was added dropwise... mL of dehydrated tetrahydrofuran (abbreviation: THF) was added to this container. After cooling this mixture to about -78 °C while stirring, 1.59 mol / It should be noted that there seems to be some incomplete information in the original text starting from line 45. The translation is done as accurately as possible based on the provided text.30 mL (48 mmol) of an n-butyllithium hexane solution of L was added dropwise, and the temperature was raised to -40 °C and then stirred for 1 hour. After that, 50 mL of dehydrated THF was added, and the mixture was cooled again to about -78 °C, and then 6.4 mL (57 mmol) of trimethyl borate was added dropwise. After the mixture was warmed to room temperature, it was stirred for 16 hours. 25 mL of water and 30 mL of 1 N dilute hydrochloric acid were added to this solution and stirred, and then the aqueous layer and the organic layer were separated. The obtained organic layer was washed once with 100 mL of saturated aqueous sodium bicarbonate and once with 100 mL of saturated brine. After washing, this solution was dried over magnesium sulfate, concentrated, and then recrystallized from toluene to obtain 10.1 g of a white solid in a yield of 70%. The synthesis scheme of Step 1 is shown below. After the temperature was raised and stirred for 1 hour, 50 mL of dehydrated THF was added, and then the mixture was cooled again to about -78 °C. After cooling to about -78 °C, 6.4 mL (57 mmol) of trimethyl borate was added dropwise. After the mixture was warmed to room temperature, it was stirred for 16 hours. 25 mL of water and 30 mL of 1 N dilute hydrochloric acid were added to this solution and stirred, and then the aqueous layer and the organic layer were separated. The obtained organic layer was washed once with 100 mL of saturated aqueous sodium bicarbonate and once with 100 mL of saturated brine. After washing, this solution was dried over magnesium sulfate, concentrated, and then recrystallized from toluene to obtain 10.1 g of a white solid in a yield of 70%. The synthesis scheme of Step 1 is shown below. The synthesis scheme of Step 1 is shown below.

[0433]

Chemical formula

[0434] <Step 2: Synthesis of BBAFLBi> In a 200 mL three-necked flask, 2.53 g (7 mmol) of 4-(9-phenyl-9H-fluoren-9-yl)phenylboronic acid, 3.34 g (7 mmol) of 4-bromo-4',4''-diphenyltriphenylamine, 2.90 g (7 mmol) of potassium carbonate, 70 mL of toluene, 12.5 mL of ethanol, and 10.5 mL of water were placed. The mixture was degassed by stirring under reduced pressure, and the inside of the flask was replaced with nitrogen. 15.7 mg (0.07 mmol) of palladium(II) acetate and 42.2 mg (0.07 mmol) of tris(o-tolyl)phosphine were added to this mixture, and it was stirred at 85 °C for 6 hours under a nitrogen stream. After the mixture was allowed to cool to room temperature, the precipitated solid was filtered off, and then the obtained solution The mixture was degassed by stirring under reduced pressure, and the inside of the flask was replaced with nitrogen. 15.7 mg (0.07 mmol) of palladium(II) acetate and 42.2 mg (0.07 mmol) of tris(o-tolyl)phosphine were added to this mixture, and it was stirred at 85 °C for 6 hours under a nitrogen stream. After the mixture was allowed to cool to room temperature, the precipitated solid was filtered off, and then the obtained solution After the mixture was allowed to cool to room temperature, the precipitated solid was filtered off, and then the obtained solution (The filtrate) was washed twice with 100 mL of water and once with 50 mL of saturated saline, and then the water was removed with magnesium sulfate. This was combined with the solid separated by filtration after the reaction above, 30 0 mL of toluene was added, and after heating to dissolve the solid, purification was carried out with Celite / Alumina / Florisil / Celite. After concentrating the obtained filtrate, ethanol was added for recrystallization to obtain 4.54 g of a white solid with a yield of 89%. The synthesis scheme of Step 2 is shown below .

[0435]

Chemical formula

[0436] 4.39 g of the obtained white solid was purified by sublimation using the train sublimation method. The sublimation purification was carried out by heating at 320 °C under the conditions of a pressure of 3.5 Pa and an argon flow rate of 15 mL / min. After sublimation purification, 2.73 g of the white solid of BBAFLP was obtained with a recovery rate of 62% .

[0437] The analysis results of the obtained white solid by nuclear magnetic resonance spectroscopy ( 1 1H NMR) are shown below. From these results, it was found that BBAFLP was obtained in this synthesis example. 1 1H NMR (CDCl3, 500 MHz): δ = 7.17 - 7.28 (m, 13H), δ = 7.31 (dd, J = 12.6 Hz, 7.4 Hz, 4H), δ = 7.37 (dd, J = 7.5 Hz , 1.1 Hz, 4H), δ = 7.40 - 7.47 (m, 10H), δ = 7.51 (d, J = 8.6 Hz, 4H) δ = 7.58 (d, J = 8.1 Hz, 4H) δ = 7.78 (d, J = 7.4 Hz, 2H).

[0438] ≪Synthesis Example 4: N-[4-(9H-carbazol-9-yl)phenyl]-N-(1,1’ -biphenyl-2-yl)-9,9’-spirobi[9H-fluorene]-2-amine (abbreviation: oYGBiSF) synthesis method≫ The structural formula of oYGBiSF is shown below.

[0439]

Chemical formula

[0440] <Step 1: Synthesis of N-(1,1’-biphenyl-2-yl)-9,9’-spirobi[9H- fluorene]-2-amine> 1.8 g (10 mmol) of 2-aminobiphenyl, 4.1 g (10 mmol) of 2- bromo-9,9’-spirobi[9H-fluorene], 0.34 g (0.80 mmol) of 2-dicyclohexylphosphino-2’,6’-dimethoxybiphenyl (abbreviation: S-P hos), and 2.0 g (20 mmol) of sodium t-butoxide were placed in a 200 mL three-necked flask equipped with a condenser tube, a three-way cock, and a rubber stopper. The system was purged with nitrogen, and 52 mL of toluene was added. After degassing the mixture under reduced pressure, the system was placed under a nitrogen stream, and the mixture was heated with stirring at 60 °C. After the system reached 60 °C, 0.24 g (0.40 mmol) of bis(dibenzylideneacetone)palladium(0) was added, and then the mixture was heated with stirring at 80 °C for two and a half hours. After heating with stirring, the precipitated solid was removed by suction filtration, and the resulting filtrate was washed three times with water and then with saturated brine. The organic layer was dried over magnesium sulfate. After drying, it was filtered naturally, and the filtrate was concentrated to obtain 3.4 g of a brown solid. The obtained brown solid was subjected to silica gel column chromatography (the mobile phase was changed from hexane:toluene = 10:1 to 2:1) Purification by gradient elution gave a white solid of the target compound. The obtained solid was recrystallized from toluene / hexane to give 3.7 g of a white solid of the target compound in a yield of 74%. The synthetic scheme of Step 1 is shown below.

[0441]

Chemical Structure

[0442] <Step 2: Synthesis of N-[4-(9H-carbazol-9-yl)phenyl]-N-(1,1 '-biphenyl-2-yl)-9,9'-spirobi[9H-fluorene]-2-amine ( abbreviation: oYGBiSF)> To 2.7 g (5.5 mmol) of N-(1,1'-biphenyl-2-yl )-9,9'-spirobi[9H-fluorene]-2-amine obtained in Step 1, 1.8 g (5.5 mmo l) of 9-(4-bromophenyl)-9H-carbazole, 0.18 g (0.40 mm ol) of 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl (abbreviation: S-Phos), and 1.1 g (11 mmol) of sodium tert-butoxide were placed in a 200 mL three-necked flask equipped with a condenser, a three-way cock, and a ground glass stopper. The system was purged with nitrogen, and 5 2 mL of toluene was added. After degassing the mixture under reduced pressure, the system was placed under a nitrogen stream, and 0.13 g (0.22 mmol) of bis(dibenzylideneacetone)palladium( 0) was added to the mixture, which was then heated and stirred at 80 °C. After heating and stirring, the precipitated solid was removed by suction filtration. The obtained filtrate was washed three times with water and then with saturated brine, and the organic layer was dried over magnesium sulfate. After drying, the mixture was filtered naturally, and the filtrate was concentrated to obtain a brown solid. The obtained brown solid was purified by silica gel column chromatography (the mobile phase was a gradient from hexane:toluene = 10:1 to 2:1), and a white solid of the target product was obtained. When the obtained solid was recrystallized with toluene / hexane, a white solid of the target product was obtained in 3.2 g with a yield of 79%.

[0443] The obtained white solid was purified by sublimation using the train sublimation method. The sublimation purification was carried out by flowing argon at 15 mL / min under a pressure of 2.9 Pa, and heating 3.2 g of the white solid at 310 °C for 15 hours. After sublimation purification, 2.9 g of colorless transparent cubic crystals of the target product were obtained with a recovery rate of 91 %. The synthesis scheme of Step 2 is shown below.

[0444] [Chemical formula]

[0445] 1H-NMR measurement of the obtained solid 1 was carried out. The measurement results are shown below. From this, it was found that oYGBiSF was obtained in this synthesis example. 1 1H NMR (dichloromethane-d2, 500 MHz): δ = 6.29 (sd, J2 = 2 .0 Hz, 1H), 6.56 (d, J = 7.5 Hz, 1H), 6.67 (d, J = 7.5 Hz, 2H), 6.86 (dt, J1 = 9.0 Hz, J2 = 2.0 Hz, 2H), 6.9 3 (dd, J1 = 8.3 Hz, J2 = 2.0 Hz, 1H), 7.00 (td, J1 = 7. 5 Hz, J2 = 1.0 Hz, 1H), 7.04 - 7.08 (m, 5H), 7.08 - 7. 11 (m, 2H), 7.14 (td, J1 = 7.5 Hz, J2 = 1.0 Hz, 2H), 7 .21 - 7.31 (m, 9H), 7.34 (td, J1 = 7.0 Hz, J2 = 1.5 Hz , 2H), 7.38 (td, J1 = 7.5 Hz, J2 = 1.0 Hz, 2H), 7.59 ( d, J = 8.0 Hz, 1H), 7.70 (d, J = 8.0 Hz, 1H), 7.79 (d, J = 8.0 Hz, 2H), 8.09 (d, J = 8.0 Hz, 2H).

Description of Symbols

[0446] 101 Anode 102 Cathode 103 EL layer 111 Hole injection layer 112 Hole transport layer 112 - 1 First hole transport layer 112 - 2 Second hole transport layer 113 Light - emitting layer 114 Electron transport layer 115 Electron injection layer 116 Charge generation layer 117 P - type layer 118 Electron relay layer 119 Electron injection buffer layer 201 Anode 202 Cathode 210 First layer 211 Second layer 212 Third layer 400 Substrate 401 Anode 403 EL layer 404 Cathode 405 Sealing material 406 Sealing material 407 Sealing substrate 412 Pad 420 IC chip 501 Anode 502 Cathode 511 First light - emitting unit 512 Second light - emitting unit 513 Charge generation layer 601 Driving circuit section (source - line driving circuit) 602 Pixel section 603 Driving circuit section (gate line driving circuit) 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 609 FPC (Flexible Printed Circuit) 610 Element substrate 611 Switching FET 612 Current control FET 613 Anode 614 Insulator 616 EL layer 617 Cathode 618 Light emitting device 951 Substrate 952 Electrode 953 Insulation layer 954 Partition layer 955 EL layer 956 Electrode 1001 Substrate 1002 Underlying insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 Gate electrode 1020 First interlayer insulating film 1021 Second interlayer insulating film 1022 Electrode 1024W Anode 1024R Anode 1024G Anode 1024B Anode 1025 Partition 1028 EL layer 1029 Cathode 1031 Sealing substrate 1032 Sealing material 1033 Transparent substrate 1034R Red colored layer 1034G Green colored layer 1034B Blue colored layer 1035 Black matrix 1036 Overcoat layer 1037 Third interlayer insulating film 1040 Pixel portion 1041 Driving circuit portion 1042 Peripheral portion 2001 Housing 2002 Light source 2100 Robot 2110 Arithmetic unit 2101 Illuminance sensor 2102 Microphone 2103 Upper camera 2104 Speaker 2105 Display 2106 Lower camera 2107 Obstacle sensor 2108 Moving mechanism 3001 Lighting device 5000 Housing 5001 Display portion 5002 Second display portion 5003 Speaker 5004 LED lamp 5006 Connection terminal 5007 Sensor 5008 Microphone 5012 Support portion 5013 Earphone 5100 Cleaning robot 5101 Display 5102 Camera 5103 Brush 5104 Operation button 5150 Portable information terminal 5151 Housing 5152 Display area 5153 Bending portion 5120 Dust 5200 Display area 5201 Display area 5202 Display area 5203 Display area 7101 Housing 7103 Display portion 7105 Stand 7107 Display portion 7109 Operation key 7110 Remote control operation unit 7201 Main body 7202 Housing 7203 Display unit 7204 Keyboard 7205 External connection port 7206 Pointing device 7210 Second display unit 7401 Housing 7402 Display unit 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 9310 Portable information terminal 9311 Display panel 9313 Hinge 9315 Housing

Claims

1. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer contains a first organic compound and a second organic compound; the second layer contains a third organic compound; the third layer contains a fourth organic compound; the light-emitting layer contains a fifth organic compound and a sixth organic compound; the fourth layer contains a seventh organic compound; the first organic compound is an organic compound exhibiting electron-accepting properties with respect to the second organic compound; the fifth organic compound is a light-emitting center substance; the second organic compound and the third organic compound are the same substance; the HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less; the seventh organic compound has an electron mobility of 1×10−7 cm2 / Vs or more and 5×10−5 cm2 / Vs or less when the square root of the electric field strength [V / cm] is 600; the HOMO level of the fourth organic compound is the same as or deeper than the HOMO level of the third organic compound; A light-emitting device, wherein the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less.

2. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer contains a first organic compound and a second organic compound; the second layer contains a third organic compound; the third layer contains a fourth organic compound; the light-emitting layer contains a fifth organic compound and a sixth organic compound; the sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton; the fourth layer contains a seventh organic compound; The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound. The fifth organic compound is a luminescent center substance. The second organic compound and the third organic compound are the same substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less. The HOMO level of the fourth organic compound is the same as the HOMO level of the third organic compound, or deeper than the HOMO level of the third organic compound. A light-emitting device, wherein the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less.

3. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, The first layer is located between the anode and the second layer. The second layer is located between the first layer and the third layer. The third layer is located between the second layer and the light-emitting layer. The light-emitting layer is located between the third layer and the fourth layer. The fourth layer is located between the light-emitting layer and the cathode. The first layer includes a first organic compound and a second organic compound. The second layer includes a third organic compound. The third layer includes a fourth organic compound. The light-emitting layer includes a fifth organic compound and a sixth organic compound. The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton. The fourth layer includes a seventh organic compound. The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound. The fifth organic compound is a luminescent center substance. The second organic compound and the third organic compound are the same substance. The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less. The LUMO level of the sixth organic compound is shallower than the LUMO level of the seventh organic compound. The difference between the LUMO level of the seventh organic compound and the LUMO level of the sixth organic compound is 0.1 eV or more and 0.3 eV or less. The HOMO level of the fourth organic compound is the same as the HOMO level of the third organic compound, or deeper than the HOMO level of the third organic compound. A light-emitting device, wherein the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less.

4. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer contains a first organic compound and a second organic compound; the second layer contains a third organic compound; the third layer contains a fourth organic compound; the light-emitting layer contains a fifth organic compound and a sixth organic compound; the sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton; the fourth layer contains a seventh organic compound; the first organic compound is an organic compound showing electron-accepting property with respect to the second organic compound; the fifth organic compound is a light-emitting center substance; the second organic compound and the third organic compound are the same substance; the HOMO level of the second organic compound is not less than -5.7 eV and not more than -5.2 eV; the seventh organic compound is a π-electron-deficient heteroaromatic compound; the HOMO level of the fourth organic compound is the same as or deeper than the HOMO level of the third organic compound; A light-emitting device, wherein the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is not more than 0.2 eV.

5. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer contains a first organic compound and a second organic compound; the second layer contains a third organic compound; the third layer contains a fourth organic compound; the light-emitting layer contains a fifth organic compound and a sixth organic compound; the fourth layer contains a seventh organic compound; the first organic compound is an organic compound showing electron-accepting property with respect to the second organic compound; The fifth organic compound is a light-emitting center substance, The second organic compound and the third organic compound are the same substance, The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, The seventh organic compound has an electron mobility of 1×10−7 cm2 / Vs or more and 5×10−5 cm2 / Vs or less when the square root of the electric field strength [V / cm] is 600, The fourth organic compound is an aromatic amine having a dibenzofuran skeleton, The HOMO level of the fourth organic compound is the same as the HOMO level of the third organic compound or deeper than the HOMO level of the third organic compound, The difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less, a light-emitting device.

6. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, The first layer is located between the anode and the second layer, The second layer is located between the first layer and the third layer, The third layer is located between the second layer and the light-emitting layer, The light-emitting layer is located between the third layer and the fourth layer, The fourth layer is located between the light-emitting layer and the cathode, The first layer has a first organic compound and a second organic compound, The second layer has a third organic compound, The third layer has a fourth organic compound, The light-emitting layer has a fifth organic compound and a sixth organic compound, The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton, The fourth layer has a seventh organic compound, The first organic compound is an organic compound showing electron-accepting properties with respect to the second organic compound, The fifth organic compound is a light-emitting center substance, The second organic compound and the third organic compound are the same substance, The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, The fourth organic compound is an aromatic amine having a dibenzofuran skeleton, The HOMO level of the fourth organic compound is the same as the HOMO level of the third organic compound or deeper than the HOMO level of the third organic compound, The difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less, a light-emitting device.

7. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer has a first organic compound and a second organic compound; the second layer has a third organic compound; the third layer has a fourth organic compound; the light-emitting layer has a fifth organic compound and a sixth organic compound; the sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton; the fourth layer has a seventh organic compound; the first organic compound is an organic compound showing electron-accepting property with respect to the second organic compound; the fifth organic compound is a light-emitting center substance; the second organic compound and the third organic compound are the same substance; the HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less; the LUMO level of the sixth organic compound is shallower than the LUMO level of the seventh organic compound; the difference between the LUMO level of the seventh organic compound and the LUMO level of the sixth organic compound is 0.1 eV or more and 0.3 eV or less; the fourth organic compound is an aromatic amine having a dibenzofuran skeleton; the HOMO level of the fourth organic compound is the same as or deeper than the HOMO level of the third organic compound; the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less. A light-emitting device.

8. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer has a first organic compound and a second organic compound; the second layer has a third organic compound; the third layer has a fourth organic compound; The light-emitting layer has a fifth organic compound and a sixth organic compound, The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton, The fourth layer has a seventh organic compound, The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound, The fifth organic compound is a light-emitting center substance, The second organic compound and the third organic compound are the same substance, The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, The seventh organic compound is a π-electron-deficient heteroaromatic compound, The fourth organic compound is an aromatic amine having a dibenzofuran skeleton, The HOMO level of the fourth organic compound is the same as the HOMO level of the third organic compound or deeper than the HOMO level of the third organic compound, A light-emitting device in which the difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less.

9. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, The first layer is located between the anode and the second layer, The second layer is located between the first layer and the third layer, The third layer is located between the second layer and the light-emitting layer, The light-emitting layer is located between the third layer and the fourth layer, The fourth layer is located between the light-emitting layer and the cathode, The first layer has a first organic compound and a second organic compound, The second layer has a third organic compound, The third layer has a fourth organic compound, The light-emitting layer has a fifth organic compound and a sixth organic compound, The fourth layer has a seventh organic compound, The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound, The fifth organic compound is a light-emitting center substance, The second organic compound and the third organic compound are the same substance, The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, The seventh organic compound has an electron mobility of 1×10−7 cm2 / Vs or more and 5×10−5 cm2 / Vs or less when the square root of the electric field strength [V / cm] is 600, The fourth organic compound is an organic compound having a carbazole skeleton, The HOMO level of the fourth organic compound is the same as or deeper than the HOMO level of the third organic compound. The difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less. A light-emitting device. **Claim 10**: An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer includes a first organic compound and a second organic compound; the second layer includes a third organic compound; the third layer includes a fourth organic compound; the light-emitting layer includes a fifth organic compound and a sixth organic compound; the sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton; the fourth layer includes a seventh organic compound; the first organic compound is an organic compound showing electron-accepting property with respect to the second organic compound; the fifth organic compound is a light-emitting center substance; the second organic compound and the third organic compound are the same substance; the HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less; the fourth organic compound is an organic compound having a carbazole skeleton; The HOMO level of the fourth organic compound is the same as or deeper than the HOMO level of the third organic compound. The difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less. A light-emitting device. **Claim 11**: An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, wherein the first layer is located between the anode and the second layer; the second layer is located between the first layer and the third layer; the third layer is located between the second layer and the light-emitting layer; the light-emitting layer is located between the third layer and the fourth layer; the fourth layer is located between the light-emitting layer and the cathode; the first layer includes a first organic compound and a second organic compound; The second layer has a third organic compound, The third layer has a fourth organic compound, The light-emitting layer has a fifth organic compound and a sixth organic compound, The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton, The fourth layer has a seventh organic compound, The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound, The fifth organic compound is a light-emitting center substance, The second organic compound and the third organic compound are the same substance, The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, The LUMO level of the sixth organic compound is shallower than the LUMO level of the seventh organic compound, The difference between the LUMO level of the seventh organic compound and the LUMO level of the sixth organic compound is 0.1 eV or more and 0.3 eV or less, The fourth organic compound is an organic compound having a carbazole skeleton, The HOMO level of the fourth organic compound is the same as or deeper than the HOMO level of the third organic compound, The difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less, a light-emitting device.

12. An anode, a first layer, a second layer, a third layer, a light-emitting layer, a fourth layer, and a cathode, The first layer is located between the anode and the second layer, The second layer is located between the first layer and the third layer, The third layer is located between the second layer and the light-emitting layer, The light-emitting layer is located between the third layer and the fourth layer, The fourth layer is located between the light-emitting layer and the cathode, The first layer has a first organic compound and a second organic compound, The second layer has a third organic compound, The third layer has a fourth organic compound, The light-emitting layer has a fifth organic compound and a sixth organic compound, The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton, The fourth layer has a seventh organic compound, The first organic compound is an organic compound that exhibits electron-accepting properties with respect to the second organic compound, The fifth organic compound is a light-emitting center substance, The second organic compound and the third organic compound are the same substance, The HOMO level of the second organic compound is -5.7 eV or more and -5.2 eV or less, The seventh organic compound is a π-electron-deficient heteroaromatic compound, The fourth organic compound is an organic compound having a carbazole skeleton, The HOMO level of the fourth organic compound is the same as the HOMO level of the third organic compound or deeper than the HOMO level of the third organic compound, The difference between the HOMO level of the fourth organic compound and the HOMO level of the third organic compound is 0.2 eV or less, a light-emitting device.

13. In any one of Claims 4, 8, and 12, The π-electron-deficient heteroaromatic compound is any one of a quinoxaline skeleton, a benzimidazole skeleton, and a triazine skeleton, a light-emitting device.

14. In any one of Claims 1 to 13, The second organic compound has a first hole-transporting skeleton, The third organic compound has a second hole-transporting skeleton, The fourth organic compound has a third hole-transporting skeleton, The first hole-transporting skeleton, the second hole-transporting skeleton, and the third hole-transporting skeleton are each independently any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton, a light-emitting device.

15. In any one of Claims 1, 5, and 9, The sixth organic compound is an organic compound composed of only hydrocarbons, The HOMO level of the sixth organic compound is deeper than the HOMO level of the fourth organic compound, The difference between the HOMO level of the fourth organic compound and the HOMO level of the sixth organic compound is 0.2 eV or more and 0.4 eV or less, a light-emitting device.

16. In any one of Claims 2 to 4, 6 to 8, and 10 to 12, The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton, The difference between the HOMO level of the fourth organic compound and the HOMO level of the sixth organic compound is less than 0.2 eV, a light-emitting device.

17. In any one of Claims 2 to 4, 6 to 8, and 10 to 12, The sixth organic compound is an organic compound having an anthracene skeleton and a heterocyclic skeleton, The fourth organic compound is an organic compound in which two carbazole rings are bonded to a naphthalene ring, a light-emitting device.

18. In Claim 17, The fourth organic compound is 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazole), a light-emitting device.

19. In any one of Claims 1 to 18, The electron mobility when the square root of the electric field strength [V / cm] of the seventh organic compound is 600 is lower than the electron mobility when the square root of the electric field strength [V / cm] of the sixth organic compound is 600, a light-emitting device.

20. In any one of Claims 1 to 19, The second organic compound is an organic compound having a dibenzofuran skeleton, a light-emitting device.

21. In any one of Claims 1 to 20, The seventh organic compound is an organic compound having a quinoxaline skeleton, a light-emitting device.

22. In any one of Claims 1 to 21, The fifth organic compound is a blue fluorescent material, a light-emitting device.

23. In any one of Claims 1 to 22, The fourth layer has a function as an electron transport layer, The electron transport layer is in contact with the light-emitting layer, a light-emitting device.

24. An electronic device having the light-emitting device according to any one of Claims 1 to 23, a sensor, an operation button, a speaker, or a microphone.

25. A light-emitting device having the light-emitting device according to any one of Claims 1 to 23, a transistor, or a substrate.

26. A lighting device having the light-emitting device according to any one of Claims 1 to 23, and a housing. Is this necessary? It is defined in the 5th line that the fourth layer is between the light-emitting layer and the cathode, and it seems that it does not fall into the claims of DE on the intellectual property system. The same applies hereinafter.

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