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

Abstract

To provide a light-emitting device having good luminous efficiency and life span and requiring a low driving voltage.SOLUTION: A light-emitting device includes an anode, a cathode, and an EL layer located between the anode and the cathode, the EL layer includes a hole injection layer, a light-emitting layer, and an electron transport layer, the hole injection layer is located between the anode and the light-emitting layer, the electron transport layer is located between the light-emitting layer and the cathode, the hole injection layer includes a first substance and a second substance, the first substance is an organic compound having hole-transporting properties and having a HOMO level of -5.7 eV or more and -5.4 eV or less, the second substance is a substance exhibiting electron accepting properties toward the first substance, and the electron transport layer is composed of a material whose resistance value is reduced by passing a current therethrough.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention is a light-emitting element, a light-emitting device, a display module, and a lighting module. The present invention relates to a display device, a light-emitting device, an electronic device, and a lighting device. The technical field of one embodiment of the invention disclosed in the present specification and the like is not limited to the technical field of products, methods, Alternatively, one aspect of the present invention relates to a process, a machine, , manufacture, or composition of matter Therefore, the technical field of one embodiment of the present invention disclosed in this specification more specifically includes the following: Semiconductor device, display device, liquid crystal display device, light emitting device, lighting device, power storage device, memory device, imaging device Examples include devices, methods for driving them, and methods for manufacturing them. . [Background technology]

[0002] Electroluminescence (EL) using organic compounds The practical application of light-emitting devices (organic electroluminescence (EL) elements) that utilize these luminescence elements is progressing. The basic structure of the device is a layer of organic compounds (EL layer) containing light-emitting materials sandwiched between a pair of electrodes. By applying a voltage to this element, carriers are injected and the recombination of the carriers occurs. By utilizing the energy, it is possible to obtain luminescence from a luminescent substance.

[0003] Since such light-emitting devices are self-emitting, when they are used as pixels in a display, Compared to flat panel displays, it has the advantage of being more visible and not requiring a backlight. A display using such a light-emitting device is suitable as a display element. Another major advantage is that it can be manufactured to be thin and lightweight. Another advantage is that it has an extremely fast response time. It is one of the signs.

[0004] In addition, these light-emitting devices can form light-emitting layers continuously in two dimensions. This is the same as point light sources such as incandescent light bulbs and LEDs, This is a feature that is difficult to obtain with linear light sources such as fluorescent lamps, so it is considered to be a surface light source that can be applied to lighting, etc. It is also highly useful as a tool.

[0005] Displays and lighting devices using such light-emitting devices are suitable for use in a wide range of electronic devices. However, research and development is ongoing to find light-emitting devices with better efficiency and life span. There are.

[0006] In Patent Document 1, a first hole transport layer is provided between a first hole transport layer in contact with a hole injection layer and a light emitting layer. Hole transporting properties with a HOMO level between the HOMO level of the transport layer and the HOMO level of the host material A configuration for applying the material is disclosed.

[0007] The properties of light-emitting devices have improved remarkably, but many other properties, including efficiency and durability, remain unclear. However, it must be said that the current technology is still insufficient to meet the high demands on the [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2011 / 065136 Brochure Summary of the Invention [Problem to be solved by the invention]

[0009] In view of the above, an object of one embodiment of the present invention is to provide a novel light-emitting device. The object of the present invention is to provide a light-emitting device having good luminous efficiency or a long life. The present invention aims to provide a light-emitting device having a low driving voltage. The purpose of this document is to:

[0010] In another embodiment of the present invention, a light-emitting device, an electronic device, and a display device each having high reliability are provided. Another embodiment of the present invention provides a light-emitting device with low power consumption. The present invention aims to provide a device, an electronic device, and a display device.

[0011] It is sufficient for the present invention to solve any one of the above problems. [Means for solving the problem]

[0012] One aspect of the present invention is a light-emitting diode having an anode, a cathode, and an EL layer located between the anode and the cathode. The EL layer has a hole injection layer, a light emitting layer, and an electron transport layer, and the hole injection layer is The electron transport layer is located between the anode and the light emitting layer, and the electron transport layer is located between the light emitting layer and the cathode. the hole injection layer having a first material and a second material, the first material being Organometallic compound with hole transporting property and HOMO level of -5.7 eV to -5.4 eV The second substance is a substance that exhibits electron accepting properties to the first substance, and the electron The electron transport layer is made of a material whose resistance decreases when a current is passed through it. It is a device.

[0013] Alternatively, in the above-described configuration, the resistance value The material that reduces the luminescence intensity is a light-emitting device containing an organometallic complex of an alkali metal or an alkaline earth metal. It is a vice.

[0014] Alternatively, in the above-described configuration, the resistance value The material that reduces the value is an organic compound having an electron transport property and an alkali metal or alkaline earth metal. and an organometallic complex of an organic group metal.

[0015] Alternatively, another aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of: Organometallic complexes of metalloids form clusters in light-emitting devices.

[0016] Alternatively, another aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of: The organometallic complexes of the group I metals are composed of nitrogen- and oxygen-containing ligands and alkali metal or alkali and a metal complex having an elemental earth metal.

[0017] Alternatively, another aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of: The organometallic complexes of the aryl metals are formed by combining a ligand containing an 8-hydroxyquinolinato structure with a monovalent metal ion. and a metal complex having a fluorine atom and a fluorine atom.

[0018] Alternatively, another aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of: Lithium complexes of the aryl group containing 8-hydroxyquinolinato ligands It is a light-emitting device that is a complex.

[0019] Alternatively, in the above-mentioned structure, the electron transport layer is a first layer and a second layer. and a layer of the first layer located between the light-emitting layer and the second layer, is located between the first layer and the cathode, and is included in the first layer and the second layer Light-emitting devices with different concentrations of alkali metal or alkaline earth metal organometallic complexes. .

[0020] Alternatively, in the above-mentioned structure, the first layer may further include an alkali metal or The concentration of the organometallic complex of the alkaline earth metal is preferably 100% or more than 100% of the alkali metal or alkali earth metal of the second layer. The concentration of the organometallic complex of the earth metal is higher than that of the light emitting device.

[0021] Alternatively, another embodiment of the present invention is a liquid crystal display device according to the above structure, wherein the second substance is an organic compound. It is a light-emitting device.

[0022] Alternatively, in the above-described structure, the light-emitting layer may include a host material and a light-emitting and a material, the light-emitting material being a blue fluorescent light-emitting device.

[0023] Alternatively, another aspect of the present invention is a device in which a sensor, an operation button, a speaker, or Or, Mike, It is an electronic device having the following:

[0024] Another embodiment of the present invention is a semiconductor device having the above structure, further comprising: It is a light emitting device having the above structure.

[0025] Another embodiment of the present invention is a lighting device having the above structure and a housing.

[0026] In this specification, the term "light-emitting device" includes an image display device using a light-emitting device. In addition, a connector, such as anisotropic conductive film or TCP (Tape) Module with Carrier Package attached, printed on TCP Modules with wiring boards or light-emitting devices with COG (Chip On Glass) s) A module in which an IC (integrated circuit) is directly mounted may also be included in the category of light-emitting device. Furthermore, lighting fixtures and the like may include a light-emitting device. Effect of the Invention

[0027] According to one embodiment of the present invention, a novel light-emitting device having a long life can be provided. It is possible to provide a light-emitting device having good light-emitting efficiency. Alternatively, a light emitting device with a low driving voltage can be provided.

[0028] In another embodiment of the present invention, a light-emitting device, an electronic device, and a display device each having high reliability are provided. In another embodiment of the present invention, a light-emitting device with low power consumption can be provided. An electronic device and a display device can each be provided.

[0029] The description of these effects does not preclude the existence of other effects. An embodiment does not necessarily have to have all of these effects. Effects other than these may also be included. The above is self-evident from the description, drawings, claims, etc. Other effects can be extracted from the claims and other descriptions. [Brief description of the drawings]

[0030] [Figure 1] 1(A1), 1(A2), 1(B) and 1(C) are schematic diagrams of light emitting devices. [Diagram 2] 2(A) and 2(B) are diagrams for explaining the extension of life. [Diagram 3] 3(A) and 3(B) are diagrams illustrating an increase in luminance. [Figure 4] 4(A) and 4(B) are conceptual diagrams of an active matrix type light emitting device. [Diagram 5] 5(A) and 5(B) are conceptual diagrams of an active matrix type light emitting device. [Figure 6] FIG. 6 is a conceptual diagram of an active matrix type light emitting device. [Figure 7] 7(A) and 7(B) are conceptual diagrams of a passive matrix type light emitting device. [Figure 8] 8(A) and 8(B) are diagrams showing a lighting device. [Figure 9] 9(A), 9(B1), 9(B2) and 9(C) are diagrams showing electronic devices. [Figure 10] 10(A), 10(B) and 10(C) are diagrams showing electronic devices. [Figure 11] FIG. 11 is a diagram showing a lighting device. [Figure 12] FIG. 12 is a diagram showing a lighting device. [Figure 13] FIG. 13 is a diagram showing an in-vehicle display device and a lighting device. [Figure 14] 14(A) and 14(B) are diagrams showing electronic devices. [Figure 15] 15(A), 15(B) and 15(C) are diagrams showing electronic devices. [Figure 16] FIG. 16 is a diagram showing an example of a Z plot of a light-emitting device according to an embodiment of the present invention. [Figure 17] FIG. 17 is a diagram showing an example of an M plot of a light-emitting device according to an embodiment of the present invention. [Figure 18] FIG. 18 illustrates an example of an equivalent circuit of a light-emitting device according to one embodiment of the present invention. [Figure 19] FIG. 19 is a diagram showing resistance values ​​for each resistance component of a light-emitting device according to one embodiment of the present invention before and after driving. [Figure 20] FIG. 20 is a graph showing the change in luminance with respect to the driving time of the light-emitting device 1 and the comparative light-emitting device 1. In FIG. [Figure 21] 21(A) and (B) are diagrams showing Z plots of Light-Emitting Device 1 and Comparative Light-Emitting Device 1. FIG. [Figure 22] FIG. 22 is a graph showing the change in voltage with respect to the driving time of the light-emitting device 1 and the comparative light-emitting device 1. In FIG. [Figure 23] FIG. 23 is a diagram showing an M plot of the light-emitting device 1. [Figure 24] FIG. 24 shows M plots of light-emitting devices 2 to 5 (FIG. 24(A)), and the resistance values ​​of each resistance component before and after driving (FIG. 24(B)). [Diagram 25] FIG. 25 shows M plots of light-emitting device 2, light-emitting device 6, and light-emitting device 7 (FIG. 25(A)), and the resistance values ​​of each resistance component before and after driving (FIG. 25(B)). [Figure 26] FIG. 26 shows M plots of light-emitting device 2 and light-emitting device 8 (FIG. 26(A)), and the resistance values ​​of each resistance component before and after driving (FIG. 26(B)). [Figure 27] FIG. 27 shows the stabilization energy per molecule in Liq multimers. [Figure 28] FIG. 28 is a diagram showing the structure of a measuring element. [Figure 29] FIG. 29 shows the frequency characteristics of the calculated capacitance C of ZADN:Liq (1:1) at a DC voltage of 7.0 V. [Diagram 30] FIG. 30 shows the frequency characteristics of -ΔB of ZADN:Liq(1:1) at a DC voltage of 7.0 V. [Diagram 31] FIG. 31 shows the electric field strength dependence of electron mobility in each organic compound. [Diagram 32] FIGS. 32(A1), 32(A2), 32(B1) and 32(B2) are diagrams showing the concentration distribution of the eighth substance in the electron transport layer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, the embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the above description, and the form and details are not limited thereto without departing from the spirit and scope of the present invention. It will be readily understood by those skilled in the art that various modifications may be made. It should not be construed as being limited to the description of the embodiment modes.

[0032] (Embodiment 1) 1A1 and 1A2 are diagrams illustrating a light-emitting device according to one embodiment of the present invention. The light-emitting device has an anode 101, a cathode 102, and an EL layer 103. The layers include a hole injection layer 111, a hole transport layer 112, a light emitting layer 113, and an electron transport layer 114. The hole transport layer 112 is made up of a first hole transport layer 112-1 and a second hole transport layer 112-2. It is preferable that the electron transport layer 114 has a first layer 112-2 as shown in FIG. It preferably has an electron transport layer 114-1 and a second electron transport layer 114-2.

[0033] In addition to these, the EL layer 103 in FIG. 1(A1)(A2) includes an electron injection layer 11. 5 is illustrated, the configuration of the light emitting device is not limited to this. If present, layers having other functions may also be included.

[0034] The hole injection layer 111 is a layer for facilitating the injection of holes into the EL layer 103. The hole injection layer 111 is made of a material having a high conductivity. The first substance has a hole transporting property and has a HOMO level of −5.7 eV or higher. The second material is an organic compound with a relatively deep HOMO level of -5.4 eV or less. The first substance has a relatively deep HOMO level. By having the above, the induction of holes is appropriately suppressed, and the hole transport of the induced holes is also improved. By configuring the hole injection layer 111 in this way, the driving Early light-emitting devices in which the carrier recombination region extended from the light-emitting layer to the electron transport layer can be produced.

[0035] The second substance can be either an inorganic or organic compound, but it must be an electron-withdrawing Use organic compounds that have groups (especially halogen groups such as fluoro groups and cyano groups). As the second substance, from among such substances, a substance having an electrical resistance to the first substance is preferably used. A substance that exhibits electron acceptability may be appropriately selected. Examples of such preferred organic compounds include For example, 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-TC NNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluorophenyl) In particular, there can be mentioned fluoro-7H-pyren-2-ylidene malononitrile. Compounds such as HAT-CN in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms. The above-mentioned compounds are preferred because they are thermally stable. In addition, the above-mentioned compounds are preferred because they have an electron-withdrawing group (especially a halogen atom such as a fluoro group). Radialene derivatives having an aryl group or a cyano group are preferred because of their high electron-accepting properties. Specifically, α,α',α''-1,2,3-cyclopropane triylidene tris[4 -cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α' '-1,2,3-Cyclopropanetriylidenetris[2,6-dichloro-3,5-difluoro Fluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1 ,2,3-Cyclopropanetriylidenetris[2,3,4,5,6-pentafluorobenzyl If the second substance is an inorganic compound, transition metals are used. In particular, the oxides of the metals belonging to groups 4 to 8 of the periodic table can be used. The oxides of metals belonging to groups 4 to 8 of the periodic table are preferred. The oxides include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, and molybdenum oxide. tungsten oxide, manganese oxide, rhenium oxide, etc. are preferred due to their high electron-accepting properties. Among them, molybdenum oxide is preferred because it is stable in the air, has low hygroscopicity, and is easy to handle. It is.

[0036] The first substance is preferably an organic compound having a hole transporting property, and , a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. It is more preferable that the dibenzofuran ring or the dibenzothiophene ring is contained. Preferred are aromatic amines having a substituent such as phenyl, ... In addition, the 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. In addition, the first substance is preferably a compound having an N,N-bis(4-biphenyl)amino group. A substance having such a structure is preferable because a light-emitting device having a long lifetime can be manufactured using such a substance. Specifically, the first substance is N-(4-biphenyl)-6,N-diphenyl. Phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-Bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]fura 4,4'-bis(6-phenylbenzo[b]naphthalene-8-amine (BBABnf) 4-phenyl-1,2-d-furan-8-yl-4''-phenyltriphenylamine (abbreviation: B nfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d] Furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl) benzyl N-benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), ,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- (Dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine ( Abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenyl BBAβNB, 4-[4-(2-naphthyl)phenyl]-4',4' '-Diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl- 4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβ NB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenyl Nylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7- phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4 ,4'-Diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthalene BBA(βN2)B-03, 4,4'-diphenyl-2-yltriphenylamine Phenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: B BAβNαNB), 4,4'-diphenyl-4''-(5;2'-binaphthyl-1-yl ) Triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)- 4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβN B) 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''- Phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl )-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine ( Abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine αNBA1BP, 4,4'-bis(1-naphthyl)triphenylamine Name: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9- YGTBi1BP, 4'- [4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(1,1'- Biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-diphenyl-4 '-(2-naphthyl)-4''-{9-(4-biphenylyl)carbazole}triphenyl Nylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol -N-[4-(1-naphthyl)phenyl]-9,9'-spiro Bi(9H-fluorene)-2-amine (abbreviation: PCBNBSF), N,N-bis(4-biphenyl) phenylyl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBAS F), N,N-bis(1,1'-biphenyl-4-yl)-9,9'-spirobi[9H- fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl- 2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spiroyl oFBiSF, N-(4-biphenyl) )-N-(dibenzofuran-4-yl)-9,9-dimethyl-9H-fluorene-2-a amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6- Phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDB fBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenyl Fluoramine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9 -yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-( 9-Phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFL Bi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenyl (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl (9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylphosphine PCBANB, 4,4'-di(1-naphthyl)-4''-(9- Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB) , N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl ]spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF), N-(1,1 '-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-ca PCBBi F) and the like.

[0037] The composition of the first material and the second material in the hole injection layer 111 is 1:0.01 to 1:0. Preferably, the weight ratio is 1:0.15. More preferably, the weight ratio is 1:0.01 to 1:0. .1 (by weight).

[0038] The hole transport layer 112 may be a single layer, but may be a layer including a first hole transport layer 112-1 and a second hole transport layer. The first hole transport layer 112-1 preferably has a second hole transport layer 112-2. The second hole transport layer 112 is located closer to the anode 101 than the layer 112-2. -2 may also function as an electron blocking layer.

[0039] The first hole transport layer 112-1 and the second hole transport layer 112-2 are made of an organic compound having a hole transporting property. The organic compound having a hole transporting property can be used as the first substance. An organic compound capable of carrying out the above-mentioned steps can be used in the same manner. The hole transporting organic compound in the first hole transport layer 112-1 and the second hole transport layer 112-2 is the same organic compound. The organic compound of the first hole transport layer 112-1 may be different from that of the first hole transport layer 112-2. The hole transporting organic compound and the first substance in the hole injection layer 111 were the same organic compound. The organic compounds may be different from each other.

[0040] The HOMO level of the first substance contained in the hole injection layer 111 and the HOMO level of the first hole transport layer 112-1 The HOMO level of the hole-transporting organic compounds in the It is preferable to select each material so that the capacitance is 0.2 eV or less.

[0041] In addition, the HOMO level of the organic compound having hole transport properties contained in the first hole transport layer 112-1 and The HOMO level of the hole-transporting organic compound contained in the second hole-transporting layer 112-2 is as follows: The deeper the latter, the better. Furthermore, the materials are selected so that the difference is 0.2 eV or less. It is preferable to select a hole transporting layer from the hole injection layer 111 to the second hole transport layer 112-2. The above-mentioned relationship between the HOMO levels of the organic compounds allows for smooth Holes are injected, and an increase in driving voltage and a state in which there are insufficient holes in the light-emitting layer can be prevented.

[0042] The first substance contained in the hole injection layer 111, the hole transport layer 112 (the first hole transport layer 1 The organic compounds having a hole transporting property contained in the first hole transport layer 112-1 and the second hole transport layer 112-2) are It is preferable that the hole transporting skeleton is an organic compound. The HOMO level of the compound is not too shallow. The anthracene skeleton and the anthracene skeleton are preferred. It is preferable that the materials contained in the overlapping layers are the same, since this facilitates the injection of holes. In particular, the hole transporting skeleton is preferably a dibenzofuran skeleton.

[0043] In addition, if the materials contained in adjacent layers are the same organic compound, hole injection becomes smoother. In particular, the first substance contained in the hole injection layer 111 and the first hole transport layer 11 It is preferable that the hole transporting organic compounds contained in 2-1 are the same material.

[0044] The light-emitting layer 113 contains a light-emitting substance and a host material. The material may contain both materials at the same time. Also, the material may be a laminate of two layers with different compositions.

[0045] The luminescent material may be a fluorescent material, a phosphorescent material, or a thermally activated delayed fluorescence (T The material may be a material that exhibits the ADF or other luminescent material. In one embodiment, the light-emitting layer 113 is a layer that exhibits fluorescent emission, in particular, a layer that exhibits blue fluorescent emission. This can be suitably applied depending on the circumstances.

[0046] In the light-emitting layer 113, examples of materials that can be used as the fluorescent material include the following: Examples include the following: Other fluorescent materials can also be used.

[0047] 5,6-Bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine PAP2BPy, 5,6-bis[4'-(10-phenyl-9-anthracene N, N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl] )phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-biphenyl Bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluorene 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-carbazo 4'-(10-phenyl-9-yl)-triphenylamine (abbreviation Name: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl N,9-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), Nyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole -3-amine (abbreviation: PCAPA), Perylene, 2,5,8,11-tetra-tert- Butylperylene (TBP), 4-(10-phenyl-9-anthryl)-4'-( 9-Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAP) A) N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1 -phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine]( Abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2- anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-t N,N,N',N ',N'',N'',N''',N'''-Octaphenyldibenzo[g,p]chrysene -2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,1 0-Diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazole-3-a 2PCAPA, N-[9,10-bis(1,1'-biphenyl-2-yl)] )-2-Anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N' -Triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10 -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)phenyl N,N,nyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), 9-Triphenylanthracene-9-amine (abbreviation: DPhAPhA), Coumarin 545 T, N,N'-Diphenylquinacridone (abbreviation: DPQd), Rubrene, 5,12-bis (1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT ), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4 H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl -6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizine -9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: D CM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,1 1-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[ij] Quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethylphenyl) tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizine 9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DC JTB), 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-tetramethyl 4H-pyrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl {N,N'-diphenyl-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b]naphtho] [1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,1 0-Bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino] ]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nb f(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenyl 3,10Fr A2Nbf(IV)-02) are particularly notable. Instead of pyrene diamine compounds such as MemFLPAPrn and 1,6BnfAPrn-03, The condensed aromatic diamine compound represented by the formula (I) has a high hole trapping property and is excellent in luminous efficiency and reliability. This is preferable because

[0048] In the case where a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, it is possible to use Examples of such materials include the following:

[0049] 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 Nyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mpt z)3]), tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H -1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrtz-3 b) Organometallic iridium complexes having a 4H-triazole skeleton, such as tris [3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-trimethyl [Ir(Mptz1-mp)3], tris(1 -Methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium (III) (abbreviation: [Ir(Prptz1-Me)3]) Organometallic iridium complexes with fac-tris[(1-2,6-diisopropyl phenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir (iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimide Dazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmp and organometallic iridium complexes having an imidazole skeleton, such as impt-Me3). Bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium( III) Tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4' ,6'-Difluorophenyl)pyridinato-N,C 2’ ]Iridium(III) picolina Fluorocarbon (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)fluorene} Phenyl]pyridinato-N,C 2’}Iridium(III) picolinate (abbreviation: [Ir( CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyri Ginat-N,C 2’ ]Iridium(III) acetylacetonate (abbreviation: FIr(ac Organometallic intercalation complexes with phenylpyridine derivatives having electron-withdrawing groups such as These are compounds that exhibit blue phosphorescence, with an emission wavelength of 440 nm. It is a compound having an emission peak at 520 nm.

[0050] In addition, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)yl Ir(tBuppm)3, diacetylacetonate (6-Methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mp pm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4- Phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(ac ac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpiperidinyl [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenyl [Pyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)] ), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(II I) (abbreviation: [Ir(dppm)2(acac)]) Metal-iridium complexes and (acetylacetonato)bis(3,5-dimethyl-2-phenyl Rupyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac) ]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyridine Dinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]) Organometallic iridium complexes with pyrazine skeletons such as tris(2-phenylpyridinium) Nat-N,C 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2- Phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium (I II) Acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(beta Tris[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]) (2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq) 3]), bis(2-phenylquinolinato-N,C 2’ ) Iridium(III) acetylated A compound with a pyridine skeleton, such as setonate (abbreviation: [Ir(pq)2(acac)]) In addition to the organometallic iridium complexes, tris(acetylacetonato)(monophenanthroline)tetraacetate Rare earth metals such as rubium(III) (abbreviation: [Tb(acac)3(Phen)]) These are mainly compounds that exhibit green phosphorescence and have wavelengths between 500 nm and 6 The emission peak is at 100 nm. The body is particularly preferred because it is remarkably excellent in reliability and luminous efficiency.

[0051] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinyl] Nat[Iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis [4,6-Bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)irid Ir(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di( Naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]) iridium complexes of the genus acetylacetonato, bis(2,3,5-triphenylpyrazine) Iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2, 3,5-Triphenylpyrazinato)(dipivaloylmethanato)iridium(III)(abbreviation Name: [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis (4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fd pq)2(acac)]) and other organometallic iridium complexes with pyrazine skeletons, Tris(1-phenylisoquinolinato-N,C2’ ) Iridium(III) (abbreviation: [Ir (piq)3]), bis(1-phenylisoquinolinato-N,C 2’ ) Iridium (II I) Pyridyl acetylacetonate (abbreviation: [Ir(piq)2(acac)]) In addition to organometallic iridium complexes with iridium skeletons, 2,3,7,8,12,13,17,18 -Octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP) Platinum complexes such as tris(1,3-diphenyl-1,3-propanedionato) (monophenyl Anthroline) europium(III) (abbreviation: [Eu(DBM)3(Phen)]), Tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthate Europium(III) (abbreviation: [Eu(TTA)3(Phen)]) These are compounds that exhibit red phosphorescence and have a wavelength of 60 The emission peak is between 0 nm and 700 nm. The rhodium complex can emit red light with good chromaticity.

[0052] In addition to the phosphorescent compounds described above, known phosphorescent light-emitting substances may be selected and used. stomach.

[0053] TADF materials include fullerene and its derivatives, acridine and its derivatives, and eosin. Derivatives of magnesium (Mg), zinc (Zn), cadmium (Cd) and other metals can also be used. (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (P d) and the like. The metal-containing porphyrin includes, for example, For example, the protoporphyrin-tin fluoride complex (SnF2(Pro to IX), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), Hematoporphyrin-Tin Fluoride Complex (SnF2(Hemato IX)), Copropor Phyllin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4M e)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etiopo Luphirin-Tin Fluoride Complex (SnF2(Etio I)), Octaethylporphyrin -platinum chloride complex (PtCl2OEP) and the like.

[0054] [ka]

[0055] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenyl)-2-phenylpropanediol having the following structural formula is also available. phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine ( Abbreviation: PIC-TRZ) and 9-(4,6-diphenyl-1,3,5-triazine-2- yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzT zn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl PCCzPT zn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl 3-[4-(5-phenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), -5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1, 2,4-Triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-azide Clydin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[ 4-(9,9-Dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9 π-electron-rich heteroaromatic rings such as '-anthracene]-10'-one (abbreviation: ACRSA) and a π-electron-deficient heteroaromatic ring, or both of these heteroaromatic rings may also be used. Since the heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, Among them, those having a π-electron-deficient heteroaromatic ring are preferred because they have high electron transport properties and hole transport properties. Among the skeletons that have pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyri The benzene skeleton) and the triazine skeleton are preferred because they are stable and reliable. Benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, The zothienopyrazine skeleton is preferred because it has high acceptor properties and good reliability. Among the skeletons having electron-rich heteroaromatic rings, the acridine skeleton, the phenoxazine skeleton, and the fluorocarbon skeleton are The ethene skeleton, the furan skeleton, the thiophene skeleton, and the pyrrole skeleton are stable and reliable. It is preferable that the compound has at least one of the furan skeletons. The dibenzofuran skeleton is used for the thiophene skeleton, and the dibenzothiophene skeleton is used for the thiophene skeleton. The pyrrole skeleton is preferably an indole skeleton, a carbazole skeleton, an indole skeleton, Carbazole skeleton, bicarbazole skeleton, 3-(9-phenyl-9H-carbazole-3 In addition, a π-electron-rich heteroaromatic ring and a π-aryl group are particularly preferred. In the case of a substance in which an electron-deficient heteroaromatic ring is directly bonded, the electron-donating property of the π-electron-rich heteroaromatic ring is utilized. The electron-accepting properties of the π-electron-deficient heteroaromatic rings are both strong, and the energies of the S1 and T1 levels are This is particularly preferred because the difference is small and thermally activated delayed fluorescence can be obtained efficiently. Instead of a π-electron deficient heteroaromatic ring, an aromatic ring with an electron-withdrawing group such as a cyano group is used. In addition, as the π-electron-rich skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. may be used. In addition, a xanthene skeleton, a thioxanthene skeleton, etc., can be used as a π-electron deficient skeleton. Dioxide skeleton, oxadiazole skeleton, triazole skeleton, imidazole skeleton, an The boron-containing skeletons such as phenylborane and boranthrene, benzonitrile, The aromatic ring or heteroaromatic ring having a nitrile group or a cyano group, such as cyanobenzene, Carbonyl skeletons such as phenones, phosphine oxide skeletons, sulfone skeletons, etc. can be used. In this way, at least one of a π-electron deficient heteroaromatic ring and a π-electron rich heteroaromatic ring can be used. In place of one another, π-electron deficient and π-electron rich backbones can be used.

[0056] [ka]

[0057] In addition, TADF materials have a small difference between the S1 and T1 levels, and can be triple-phased by reverse intersystem crossing. The function of converting energy from first excitation energy to singlet excitation energy Therefore, the triplet excitation energy can be converted to a single state by a small amount of thermal energy. It is possible to upconvert to singlet excited energy (reverse intersystem crossing), and efficiently convert singlet excited states It is possible to generate triplet excitation energy and convert it into luminescence. .

[0058] In addition, exciplexes (complexes) that form excited states with two types of substances The difference between the S1 and T1 levels is extremely small. As a TADF material capable of converting triplet excitation energy into singlet excitation energy, It has all the functions.

[0059] As an index of the T1 level, the phosphorescence spectrum observed at low temperatures (e.g., from 77 K to 10 K) As for the TADF material, Draw a tangent line to the S1 level, and the energy of the wavelength of the extrapolated line is the S1 level of the phosphorescence spectrum. When a tangent line is drawn at the long side of the tail and the energy of the wavelength of the extrapolated line is taken as the T1 level, The difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less. Even more preferred.

[0060] In addition, when a TADF material is used as a light-emitting material, the S1 level of the host material is The T1 level of the host material is preferably higher than the S1 level of the TADF material. It is preferable that the concentration is higher than the above level.

[0061] The host material of the light-emitting layer may be a material having an electron transporting property or a material having a hole transporting property. Various carrier transport materials can be used, such as TADF materials.

[0062] Materials with hole transport properties include those having an amine skeleton or a π-electron-rich heteroaromatic skeleton. Organic compounds are preferred. For example, 4,4'-bis[N-(1-naphthyl)-N-phenylalanine] N,N'-bis(3-methylphenyl)-N,N' -Diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4, 4'-Bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino] ]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9 -yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenyl mBPAFLP, 4-phenyl 4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation : PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazo PCBBi1BP), 4-(1-naphthyl-3-yl)triphenylamine )-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation : PCBAN B), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazone) PCBNBB, 9,9-dimethyl -N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl ]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl Nyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-bifluorene-2 -amine (abbreviation: PCBASF), and compounds with aromatic amine skeletons such as 1,3-biphenyl mCP, 4,4'-di(N-carbazolyl)benzene Biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenyl Nylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazo Compounds with a carbazole skeleton, such as PCCP (abbreviation: PCCP), and 4,4',4'' -(Benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P -II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl] 4-[4-(9-phenyl)dibenzothiophene (abbreviation: DBTFLP-III) Phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) and other compounds with thiophene skeletons, such as 4,4',4' '-(Benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P- II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]fluor phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) Among the above, compounds having an aromatic amine skeleton and carbazole Compounds having such a structure have good reliability and high hole transport properties, and are therefore useful for reducing the driving voltage. In addition, the organic compounds listed as examples of the first substance may also be used. This can be done.

[0063] As an example of a material having electron transport properties, bis(10-hydroxybenzo[h]quinoli Nat)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) Metal complexes such as phenolatozinc(II) (abbreviation: ZnBTZ) and π-electron-deficient heteroaromatic complexes Organic compounds having an aromatic ring skeleton are preferred. Organic compounds having a π-electron deficient heteroaromatic ring skeleton Examples of the compounds include 2-(4-biphenylyl)-5-(4-tert-butylphenyl) )-1,3,4-Oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4- Phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxa 9-[4-(5-phenyl-1-azolyl]benzene (abbreviation: OXD-7), ,3,4-Oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO 11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl- 1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophene-4 -yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm Heterocyclic compounds with polyazole skeletons such as 2-[3-(dibenzothiophene-2-yl)-II] and 2m-phenyl-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDB q-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]di Benzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-( 9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxalate 2mCzBPDBq, 4,6-bis[3-(phenanthren-9-yl)phenyl]phenyl phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-diphenyl Diazothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II) Heterocyclic compounds with an amine skeleton and 2-[3'-(9,9-dimethyl-9H-fluorene -2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5- Triazine (abbreviation: mFBPTzn), 2-[(1,1'-biphenyl)-4-yl]- 4-Phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1,3, 5-Triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo "b" naphtho[ 1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3, 5-Triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo "b" naphtho [1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3 ,5-triazine (abbreviation: mBnfBPTzn-02), etc. Heterocyclic compounds and 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine Din (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl] Heterocyclic compounds with a pyridine skeleton, such as benzene (abbreviation: TmPyPB), are examples. Among the above, heterocyclic compounds having a diazine skeleton and heterocyclic compounds having a triazine skeleton are Compounds having a pyridine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their high reliability. Heterocyclic compounds with an azine (pyrimidine or pyrazine) skeleton and those with a triazine skeleton The heterocyclic compound has a high electron transporting property and contributes to reducing the driving voltage.

[0064] The TADF materials that can be used as host materials are listed above as TADF materials. When a TADF material is used as a host material, the TA The triplet excitation energy generated in the DF material is converted to singlet excitation energy by reverse intersystem crossing. This energy is then transferred to the light-emitting material, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material acts as an energy donor and the light-emitting material acts as an energy acceptor.

[0065] This is particularly effective when the luminescent material is a fluorescent luminescent material. To obtain high luminous efficiency, the S1 level of the TADF material should be higher than the S1 level of the fluorescent material. In addition, 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. Higher is preferred.

[0066] 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.

[0067] 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 that the compound has a protecting group around the skeleton that causes light emission. A substituent having no carbon atom is preferable, and a saturated hydrocarbon is preferable. Specifically, the substituent has 3 to 10 carbon atoms. The alkyl groups listed below, substituted or unsubstituted cycloalkyl groups with 3 to 10 carbon atoms, A trialkylsilyl group having a number of 3 to 10 is preferred, and a group having a plurality of protecting groups is more preferred. Substituents without π bonds have poor carrier transport function, and therefore have poor carrier transport and The distance between the TADF material and the luminophores of the fluorescent material can be reduced without affecting carrier recombination. Here, the luminophore is the molecule that causes the emission of light in a fluorescent substance. The luminophore preferably has a skeleton with a π bond and contains an aromatic ring. It is preferable that the aromatic ring has a condensed aromatic ring or a condensed heteroaromatic ring. The heterocyclic aromatic rings include phenanthrene skeletons, stilbene skeletons, acridone skeletons, and pheno In particular, the naphthalene skeleton, the anthracene skeleton, and the like can be used. skeleton, fluorene skeleton, chrysene skeleton, triphenylene skeleton, tetracene skeleton, pyrene skeleton It has a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton. Such fluorescent substances are preferred because they have high fluorescence quantum yields.

[0068] When a fluorescent substance is used as the light-emitting substance, the host material is a material having an anthracene skeleton. A material having an anthracene skeleton is preferably used as a host material for a fluorescent material. When used as a host material, it is possible to realize a light-emitting layer having good light-emitting efficiency and durability. The anthracene skeleton used as the material includes a diphenylanthracene skeleton, In particular, a substance having a 9,10-diphenylanthracene skeleton is preferred because it is chemically stable. In addition, when the host material has a carbazole skeleton, the hole injection / transport properties are improved. However, a benzocarbazole skeleton in which a benzene ring is further condensed to a carbazole is preferable. When it contains carbazole, the HOMO becomes shallower by about 0.1 eV than that of carbazole, making it easier for holes to enter. In particular, when the host material contains a dibenzocarbazole skeleton, The HOMO is shallower than that of the sol by about 0.1 eV, making it easier for holes to enter, and the hole transport Therefore, it is more preferable as a host material. Preferred are 9,10-diphenylanthracene and carbazole skeletons (or It is a substance that simultaneously has a benzocarbazole skeleton and a dibenzocarbazole skeleton. From the viewpoint of the hole injection and transport properties, a benzofluorene skeleton was used instead of a carbazole skeleton. Dibenzofluorene and dibenzofluorene skeletons may also be used. Examples of such materials include 9-phenyl 3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole ( Abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H- Carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl) phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9 -anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBC zPA), 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}anthra 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]phenyl Nyl]anthracene (abbreviation: αN-βNPAnth), etc. cgDBCzPA, 2mBnfPPA, and PCzPA are preferred because they show very good properties. This is a good choice.

[0069] The host material may be a mixture of a plurality of substances. When used, a material having an electron transporting property and a material having a hole transporting property may be mixed. It is preferable to mix a material having an electron transporting property with a material having a hole transporting property. In this way, the transport properties of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The weight ratio of the content of the material having a hole transporting property to the content of the material having an electron transporting property is The ratio of the material having hole transport properties to the material having electron transport properties may be from 1:19 to 19:1.

[0070] A phosphorescent material can be used as a part of the mixed material. When a fluorescent substance is used as a luminescent substance, the luminescent substance transfers excitation energy to the fluorescent substance. It can be used as an energy donor.

[0071] In addition, these mixed materials may form an exciplex. The luminescence of the exciplex is such that it overlaps with the wavelength of the lowest energy absorption band of the By selecting such a combination, energy transfer becomes smooth and light emission can be obtained efficiently. In addition, the use of this configuration is also preferable because the driving voltage can be reduced.

[0072] At least one of the materials forming the exciplex may be a phosphorescent material. In this way, triplet excitation energy is efficiently converted to singlet excitation energy by reverse intersystem crossing. can be converted to

[0073] As a combination of materials that efficiently form exciplexes, HO It is preferable that the MO level of the material having electron transport properties is equal to or higher than the HOMO level of the material having hole transport properties. When the LUMO level of the material having the electron transport property is higher than the LUMO level of the material having the electron transport property, It is preferable that the LUMO level and the HOMO level of the material are determined by cyclic voltammetry. From the electrochemical properties (reduction potential and oxidation potential) of the material measured by CV measurement It can be derived.

[0074] The formation of an exciplex is based on, for example, the emission spectrum of a material having hole transport properties, the electron transport properties, The emission spectrum of the material having the above structure and the emission spectrum of the mixed film of these materials are shown in Fig. In comparison, the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material ( This can be confirmed by observing the phenomenon of a new peak on the long wavelength side. Alternatively, the transient photoluminescence (PL) of a material with hole transport properties and the electron transport properties The transient PL of the materials with the same properties and the transient PL of the mixed film of these materials were compared. The transient PL lifetime of the film has a longer-lived component than the transient PL lifetime of each material, or has a delayed component. This can be confirmed by observing the difference in the transient response, such as the percentage of In addition, the above-mentioned transient PL may be read as transient electroluminescence (EL). That is, the transient EL of a material with hole transport properties and the transient E of a material with electron transport properties are By comparing the transient EL of the L and the mixed films and observing the difference in the transient response, The formation of the exciplex can be confirmed.

[0075] In the light-emitting device according to one embodiment of the present invention, the electron transport layer 114 is a resistor that is formed by passing a current through it. The electron transport layer 114 is made of a material that reduces the resistance by passing a current through it. When the material has a low resistance, it becomes possible to pass a current through the material, i.e. to drive the light-emitting device. By this, a light-emitting device in which the resistance value of the electron transport layer 114 decreases can be fabricated. Here, in the initial stage of operation, the recombination region of carriers is not only the light-emitting layer but also the electron transport layer. If a light-emitting device is designed that extends to the transmission layer, the electrons will be released as the operating time elapses. The increased transportability of the transport layer 114 changes the carrier balance, and the recombination region on the cathode side A light-emitting device in which a change occurs such that the end portion moves toward the light-emitting layer 113 can be obtained. Since almost no energy of the carriers recombined in the electron transport layer 114 is converted into light emission, The recombination region that had spread to the electron transport layer 114 is pushed back to the light emitting layer 113 side. This reduces the loss of recombination energy. It is possible to obtain a light-emitting device with increased luminance and luminance. The light-emitting device is designed to prevent the rapid deterioration at the initial stage of operation, known as initial deterioration, by increasing the luminance. This allows the initial deterioration to be small, resulting in a very good operating life. This type of light-emitting device is called Recombinant Light-Emitting Device. Ination-Site Tailoring Injection Element (ReSTI These elements will be referred to as

[0076] In addition, in the initial stage of operation, the recombination region of carriers spreads not only to the light-emitting layer but also to the electron transport layer. In order to fabricate an optical device, the hole injection layer 111 is formed of a material having hole transport properties and its HOMO A first substance having a relatively deep HOMO level between -5.7 eV and -5.4 eV. and a second substance that exhibits electron accepting properties with respect to the first substance. .

[0077] Materials whose resistance value decreases when a current is passed through them include alkali metals or alkali Materials containing organometallic complexes of alkali metals or al-earth metals are preferred. Even if the organometallic complex is formed only of potassium earth metals, it is not possible to use alkali metals or alkaline earth metals. It may be composed of an organometallic complex of metal and other substances. Materials that reduce resistance include those other than organometallic complexes of alkali metals or alkaline earth metals. In the case where a substance is included, the substance is preferably an organic compound having an electron transport property. .

[0078] In addition, materials whose resistance value decreases when an electric current is passed through them include alkali metals or alkali If an organometallic complex of an alkali metal or alkaline earth metal is included, The organometallic complex is preferably a complex that forms a cluster when a current is passed through it. When the complex forms a cluster, the electron transport property is increased, and the resistance value of the electron transport layer 114 is It is possible to obtain a light emitting device in which the

[0079] In particular, an organic metal complex of an alkali metal or an alkaline earth metal and an organic compound having an electron transport property In the case of a material containing a compound, the complex forms a cluster by passing an electric current through it. When the electrons gather together, the organic compounds that have electron transport properties also inevitably move closer to each other. This thickens the conductive paths between the organic compounds with electron transport properties, The electron transporting property of the electron transport layer 114 is increased, so that the resistance value of the electron transport layer 114 is decreased. It will be possible to obtain a chair.

[0080] The organic compound having an electron transport property is an organic compound having an electron transport property more predominantly than a hole transport property. A compound whose electron mobility is 1 at a square root of electric field strength [V / cm] of 600. ×10 -7 cm 2 / Vs or more 5×10 -5 cm 2 It is preferable that the organic compound is an organic compound having a Vs value of 0.1 or less. When the mobility of electrons in the electron transport layer is within the above range, the electrons can be easily transported to the light emitting layer. The amount of the injected electrons can be controlled, and the light-emitting layer can be prevented from becoming excessively electron-rich. .

[0081] In addition, the organic compound having the electron transport property has a HOMO level of -6.0 eV or more. In addition, the organic compound having an electron transporting property is preferably an anthracene skeleton. The compound is preferably an organic compound having both an anthracene skeleton and a heterocyclic skeleton. The heterocyclic skeleton is preferably a nitrogen-containing five-membered ring skeleton, The nitrogen-containing five-membered ring skeleton includes a pyrazole ring, an imidazole ring, an oxazole ring, a thiazolyl ring, It is particularly preferred that the aryl group has a nitrogen-containing five-membered ring structure containing two heteroatoms in the ring, such as a zole ring. stomach.

[0082] Organometallic complexes of alkali metals or alkaline earth metals are formed with nitrogen- and oxygen-containing ligands. It is preferable that the metal complex has an alkali metal or an alkaline earth metal. In the present invention, an organometallic complex of an alkali metal or alkaline earth metal is formed in the 8-hydroxyquinolinato structure. It is preferable that the metal complex has a ligand containing a structure and a monovalent metal ion, and the metal complex has an 8-hydroxyl group. More preferably, it is a lithium complex having a ligand containing a quinolinato structure. Specifically, 8-hydroxyquinolinato-lithium (abbreviation: Liq), 8-hydroxyquinolinato-lithium (abbreviation: Liq), Examples include sodium nolinate (abbreviation: Naq). Lithium quinolinato (abbreviation: Liq) is preferred.

[0083] The electron transport layer 114 is made of an organic compound having electron transport properties and aluminum in the thickness direction. There may be areas where the mixture ratio of potassium metal or alkaline earth metal with the organometallic complex is different. The mixing ratio is determined by the ratio of the alkali metal or alkaline earth metal organometallic complexes on the cathode side. It is preferable that the mixing ratio of the time-of-flight secondary ions is small. Mass spectrometry (ToF-SIMS: Time-of-flight secondary i It is estimated based on the amount of atoms and molecules detected by mass spectrometry (MSMS). In the same two-material mixture with different mixing ratios, ToF -The magnitude of each value detected by SIMS analysis is the magnitude of the atoms, molecules, and ions of interest. Therefore, the organic compounds and alkali metals that have the electron transport property or by comparing the amount of substances detected that are derived from alkaline earth metal organometallic complexes. It is also possible to get an idea of ​​the mixing ratio.

[0084] That is, the electron transport layer 114 includes a first electron transport layer 114-1 and a second electron transport layer 114-2. 4-2 is present, the first electron transport layer is present on the anode side relative to the second electron transport layer, and the first Concentration of alkali metal or alkaline earth metal organometallic complexes in the electron transport layer and the second electron transport It is preferred that the layers have different concentrations of alkali metal or alkaline earth metal organometallic complexes. The concentration of the organometallic complex of an alkali metal or an alkaline earth metal is It is preferable that the first electron transport layer is denser than the second electron transport layer because this allows a device with a longer life to be obtained. I wish.

[0085] In addition, the organic compound having electron transport properties contained in the electron transport layer 114 and an alkali metal or The abundance ratio of alkaline earth metals and organometallic complexes is shown in Figure 1(A1) as a clear layer. If there is no boundary, the change may be continuous as in Fig. 32(A1)(A2), or If it is clear that the layers are separated as in 1(A2), see Figure 32(B1)(B2). In addition, the electron transporting property of the electron transport layer 114 may change stepwise as shown in FIG. The rate-limiting region is the region with low concentration of alkali metal or alkaline earth metal organometallic complexes. A region having a high concentration of an organometallic complex of an alkali metal or an alkaline earth metal on the light-emitting layer 113 side. In other words, in the electron transport layer 114, , the abundance (concentration) of organometallic complexes of alkali metals or alkaline earth metals is increasing There is a region or regions of alkali metal or alkaline earth metal in the electron transport layer 114. The region with the highest abundance (concentration) of organometallic complexes of the group is closer to the anode than the region with the lowest abundance (concentration). It is preferred that it is present.

[0086] The electron transporting organic compound contained in the electron transport layer 114 is the same as that used in the host material. or a host material for the fluorescent material. The organic compounds listed above as usable in the above-mentioned method can be used.

[0087] In addition, the average electric field strength [V / cm] of the organic compound having electron transport properties contained in the electron transport layer 114 is The electron mobility at the root of 600 is smaller than that of the host material or the light-emitting layer 113. It is preferred.

[0088] When the light-emitting layer becomes in an electron-rich state, the recombination region 113-1 is formed as shown in FIG. By limiting the area to a specific area, the burden on that area increases, accelerating deterioration. Also, electrons passing through the light-emitting layer without being able to recombine will reduce the lifetime and light-emitting efficiency. In one embodiment of the present invention, the electron transport property of the electron transport layer 114 is reduced, so that the electron transport property of the electron transport layer 114 is reduced. As shown in FIG. 1B, the recombination region 113-1 is expanded to distribute the load on the material constituting the light-emitting layer 113. By dispersing the light, it is possible to provide a light emitting device having a long life and good light emitting efficiency.

[0089] In addition, in a light-emitting device having such a configuration, a driving test under a constant current density condition is performed. In the luminance degradation curve obtained by the above method, a shape having a maximum value may be observed. That is, the deterioration curve of the light-emitting device according to one embodiment of the present invention shows that the luminance increases with time. Light-emitting devices that exhibit this type of degradation behavior are known as This increase in brightness can offset the initial degradation that occurs during the initial period of operation. This results in a light-emitting device with small initial deterioration and extremely good operating life. This type of light-emitting device is called the Recombination Site T. We call this element the ReSTI element.

[0090] If you take the derivative of a deterioration curve that has such a maximum value, there will be a part where the value is 0. Therefore, in one embodiment of the present invention, there is a portion where the differential of the deterioration curve is 0. The optical device has little initial deterioration and is a light-emitting device with a very long life. Cut.

[0091] The behavior of the degradation curve described above is due to the electron transport in the early stage of operation, as shown in FIG. The recombination that does not contribute to light emission due to the low electron mobility in the layer is called the non-radiative recombination region. This phenomenon is believed to be caused by the above-mentioned configuration. In the light-emitting device of the present invention, the hole injection barrier is small at the beginning of operation (HOMO of the first substance). The recrystallization rate is low due to the low electron transporting capacity of the electron transport layer 114 and the low electron transporting capacity of the electron transport layer 114. A junction region 113-1 is formed extending from the light-emitting layer 113 to the electron-transporting layer 114. In addition, the HOMO level of the organic compound having electron transport properties contained in the electron transport layer 114 is −6 At a relatively high value of 0.0 eV or more, the H of organometallic complexes of alkali metals or alkaline earth metals Since the OMO levels are at similar positions, holes can easily reach the electron transport layer 114. Recombination also occurs in the electron transport layer 114, making it easier for a non-radiative recombination region 120 to form.

[0092] In the light-emitting device according to one embodiment of the present invention, the carrier The balance changes, and the end of the recombination region 113-1 on the cathode side becomes a hole transport region as shown in FIG. 3(B). This causes the non-radiative recombination region 120 to decrease, and the recombination This allows the energy of the combined carriers to contribute effectively to light emission, and This increase in brightness occurs at the beginning of the operation of the light-emitting device. By offsetting the initial deterioration, the initial deterioration is small, and the light-emitting device has a long operating life. This makes it possible to provide a device that

[0093] Here, the present inventors have determined that the change in carrier balance in a light-emitting device according to one embodiment of the present invention is , caused by a change in the resistance of the light emitting device, in particular the resistance of the electron transport layer 114. This was verified experimentally. The change in resistance was measured by impedance spectroscopy (IS). was measured.

[0094] In impedance spectroscopy, a small sinusoidal voltage signal [V = V 0exp(iωt)] and the response current signal [I=I0exp{i(ωt+φ)} The impedance (Z=V / I) can be calculated from the phase difference between the current amplitude of Cut.

[0095] The frequency of the applied voltage signal is used as a parameter, and the obtained impedance is displayed on the complex plane. The result is called a Nyquist plot. Calculate the fundamental transfer functions, such as admittance (Y), modulus (M), and dielectric constant (ε), etc. The relationship between the transfer functions is shown below.

[0096] [Table 1]

[0097] In this embodiment, the impedance (Z) plot shows the resistance component on the real axis, and the capacitance The light-emitting devices were analyzed using modulus (M) plots, which show the reciprocal of the mass component. Table 2 shows the element configuration of the light-emitting device that was measured.

[0098] [Table 2]

[0099] An example of a Z plot of a light-emitting device according to one embodiment of the present invention is shown in FIG. Since this represents the resistance component, it can be seen that the resistance after driving is significantly lower than the resistance before driving. As described above, the light-emitting device according to one embodiment of the present invention exhibits a large resistance before and after driving. It was found that the resistance of the light emitting device after driving was lower than that before driving.

[0100] Next, the M plot of the same light-emitting device is shown in Figure 17. Software ZView (Scribner Associates) The equivalent circuit of this light-emitting device was obtained by fitting the circuit by the FT-IR ... It can be expressed as four RC parallel circuits and one series resistor as shown in Figure 18. The values ​​in the lot represent the resistance components of the corresponding equivalent circuits obtained by fitting. This indicates the location.

[0101] In addition, Fig. 19 shows the resistance before and after driving for each resistance component shown in the equivalent circuit in Fig. 18. From this, it was found that only resistor R2 had a resistance that was smaller by more than one order of magnitude.

[0102] Therefore, we measured which layer each resistance component corresponds to by changing the film thickness, and then increased the film thickness. From the change in the M plot and the increase in resistance when the It was confirmed that.

[0103] From these results, it is possible to determine whether the electron transport layer 114 is It was confirmed that the resistance decreased and the electron transporting property of the electron transport layer 114 increased. By increasing the electron transporting property of the electron transport layer 114, the carrier balance is changed as described above. The end of the recombination region that had extended to the electron transport layer moves toward the light-emitting layer, and the non-light-emitting The recombination area 120 is reduced. As a result, recombination inside the light-emitting layer increases, and the recombination energy This allows the energy to effectively contribute to light emission. The device is a light-emitting device that exhibits a characteristic behavior in which the luminance increases compared to the initial operating state. become.

[0104] In this way, the resistance of the light-emitting device according to one embodiment of the present invention is lower after driving than before driving. It was found that the resistance of the electron transport layer is reduced by driving the device. This shows that the electron transport layer drives the light-emitting device, i.e., passes the current. This means that the insulating layer is made of a material whose resistivity decreases as the insulating layer is heated.

[0105] The light-emitting device of one embodiment of the present invention having the above-described structure has an extremely long life. In particular, it is possible to use it as a device in the region where degradation is extremely small up to about LT95. It is possible to significantly extend the lifespan.

[0106] In addition, by suppressing the initial deterioration, one of the major weaknesses of OLED devices is The problem of image sticking is still being debated, and the aging method before shipment is being used to reduce it. It is possible to significantly reduce the time.

[0107] (Embodiment 2) Next, examples of the detailed structure and materials of the above-mentioned light-emitting device will be described. As described above, the light-emitting device is made of a plurality of layers between a pair of electrodes, an anode 101 and a cathode 102. The EL layer 103 is provided with a hole injection layer 104 at least on the anode 101 side. 111, a first hole transport layer 112-1, a second hole transport layer 112-2, a light emitting layer 113 and and an electron transport layer 114.

[0108] The layers other than the EL layer 103 are not particularly limited, and may be a hole injection layer, a hole transport layer, etc. layer, electron transport layer, electron injection layer, carrier block layer, exciton block layer, charge generation layer, etc. , various layer structures can be applied.

[0109] The anode 101 is made of a metal, alloy, or conductive compound having a large work function (specifically, 4.0 eV or more). It is preferable to form the insulating layer using a material such as a material having a molecular weight of 100 or more, or a mixture thereof. Indium Tin Oxide (ITO), silicon or Indium oxide-tin oxide, indium oxide-zinc oxide, oxide Examples include indium oxide containing tungsten and zinc oxide (IWZO). These conductive metal oxide films are usually formed by sputtering, but they can also be formed by sol-gel methods. As an example of the manufacturing method, indium oxide-zinc oxide The sputtering was performed using a target containing 1 to 20 wt% zinc oxide in indium oxide. Also, the method of forming the tungsten oxide and zinc oxide is Indium oxide (IWZO) is a material that is made by mixing 0.5 to 5 tungsten oxide with indium oxide. The target contained 0.1-1 wt% zinc oxide. Other materials include gold (Au), platinum (Pt), nickel (Ni), and titanium. W, Chromium (Cr), Molybdenum (Mo), Iron (Fe), Cobalt (Co) , copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride), etc. Graphene can also be used. Representative materials for forming the electrode have been listed above. In one embodiment of the present invention, the hole injection layer 1 11, an organic compound having a hole transporting property and a substance exhibiting an electron accepting property with respect to the organic compound Since a composite material containing the above is used, the electrode material can be selected regardless of the work function.

[0110] In this embodiment, the EL layer 103 has a stacked structure as shown in FIGS. As shown in FIG. 1, the hole injection layer 111, the first hole transport layer 112-1, the second hole transport layer 112-2, The light-emitting layer 113, the electron transport layer 114 (the first electron transport layer 114-1, the second electron transport layer 11 4-2) and the structure having an electron injection layer 115 in addition to the above; and Two types of structures having a charge generating layer 116 instead of the charge generating layer 115 will be described. The materials constituting the layers are specifically shown below.

[0111] A hole injection layer 111, a hole transport layer 112 (a first hole transport layer 112-1, a second hole transport layer 112-2), the light-emitting layer 113 and the electron transport layer 114 (first electron transport layer 114-1, second electron transport layer 114-2, The electron transport layer 114-2) of the second embodiment has been described in detail in the first embodiment, so the description will be repeated. The description is omitted. Please refer to the description in the first embodiment.

[0112] Between the electron transport layer 114 and the cathode 102, an electron injection layer 115 is formed. Alkalis such as LiF, cesium fluoride (CsF), calcium fluoride (CaF2), etc. A layer containing an alkali metal or an alkaline earth metal or a compound thereof may be provided. 15 is a layer made of a substance having an electron transporting property, in which an alkali metal or an alkaline earth metal or A material containing such a compound or an electride may be used. For example, a substance in which electrons are highly added to a mixed oxide of calcium and aluminum is Examples include:

[0113] 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 P-type layer 1 may be formed by laminating a film containing an acceptor material and a film containing a hole transport material. By applying a potential to the cathode 102, electrons are transported to the electron transport layer 114. Holes are injected and the light emitting device operates.

[0114] 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.

[0115] 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.

[0116] 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 (oxides such as lithium oxide, halides, lithium carbonate, etc.) (including carbonates such as tium and cesium carbonate), alkaline earth metal compounds (oxides, halogens, etc.) compounds of rare earth metals (including oxides, halides, carbonates) or compounds of rare earth metals (including oxides, halides, carbonates) It is possible to use a material with high electron injection properties such as fluorine.

[0117] The electron injection buffer layer 119 contains a substance having an electron transporting property and an electron donating substance. When formed, the electron donor is an alkali metal, an alkaline earth metal, a rare earth metal, Metals and their compounds (alkali metal compounds (oxides such as lithium oxide, halogens cations, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (oxides compounds of rare earth metals (including oxides, halides, carbonates) , including carbonates), as well as tetrathianaphthacene (abbreviation: TTN), nickelocene, deca Organic compounds such as methylnickelocene can also be used. The material is the same as that of the electron transport layer 114 described above. It is possible.

[0118] The material for forming the cathode 102 is gold, which has a small work function (specifically, 3.8 eV or less). Metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs). , and elements such as magnesium (Mg), calcium (Ca), and strontium (Sr) Elements belonging to Group 1 or 2 of the periodic table and alloys containing these elements (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.

[0119] 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.

[0120] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0121] 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.

[0122] 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, the band gap is determined by the luminescent material constituting the luminescent layer or the luminescent material contained in the luminescent layer. It is preferable that the material has a band gap larger than the band gap of the material. I wish.

[0123] Next, we developed a light-emitting device (a stacked element, a tandem element) that has a structure in which multiple light-emitting units are stacked. The embodiment of the light-emitting device (also referred to as a "light-emitting diode") will be described with reference to FIG. A light-emitting device having multiple light-emitting units between an electrode and a cathode. The EL layer 103 has a structure similar to that of the EL layer 103 shown in FIG. That is, the light-emitting device shown in FIG. 1C is a light-emitting device having a plurality of light-emitting units. The light-emitting devices shown in Figs. 1(A1), 1(A2) and 1(B) each have one light-emitting unit. It can be said that this is a light-emitting device.

[0124] In FIG. 1C, a first light-emitting unit 511 and a second light-emitting unit 512 are disposed between an anode 501 and a cathode 502. The second light-emitting unit 512 is laminated, and the first light-emitting unit 511 and the second light-emitting unit A charge generating layer 513 is provided between the anode 501 and the cathode 502. These correspond to the anode 101 and the cathode 102 in FIG. 1(A1), and are described in the explanation of FIG. 1(A1). The same as described above can be applied. In addition, the first light-emitting unit 511 and the second light-emitting unit 512 can be used. The light emitting units 512 may be of the same or different configurations.

[0125] When a voltage is applied between the anode 501 and the cathode 502, the charge generating layer 513 emits light from one of the light emitting units. The luminescent unit has a function of injecting electrons into one luminescent unit and injecting holes into the other luminescent unit. In 1(C), when a voltage is applied so that the anode potential is higher than the cathode potential, In this case, the charge generating layer 513 injects electrons into the first light emitting unit 511 and Any material capable of injecting holes into the gate 512 may be used.

[0126] The charge generation layer 513 is formed to have the same structure as the charge generation layer 116 described in FIG. The composite material of an organic compound and a metal oxide has the following advantages: Since the light-emitting unit has excellent characteristics, it can be driven at low voltage and low current. When the anode side surface of the charge generating layer 513 contacts the charge generating layer 513, the charge generating layer 513 becomes the light emitting unit. Since the EL element can also function as a hole injection layer for the light-emitting unit, the light-emitting unit does not need to have a hole injection layer. Both are good.

[0127] In addition, when the charge generating layer 513 is provided with the electron injection buffer layer 119, the electron injection buffer Since the anode layer 119 plays the role of an electron injection layer in the light-emitting unit on the anode side, the light-emitting The unit does not necessarily need to have an electron injection layer.

[0128] Although the light-emitting device having two light-emitting units has been described with reference to FIG. 1C, the light-emitting device having three or more light-emitting units may be used. The same can be applied to a light-emitting device in which the above light-emitting units are stacked. As in the light-emitting device according to the present embodiment, a plurality of light-emitting units are electrically connected between a pair of electrodes. By separating the layers with the generation layer 513, high-luminance light emission is possible while keeping the current density low. This allows the realization of an element with even longer life. In addition, it is possible to realize an element that can be driven at a low voltage and has low power consumption. The device can be realized.

[0129] In addition, by making the light color of each light-emitting unit different, the entire light-emitting device For example, a light-emitting device having two light-emitting units can be used to obtain light of a desired color. In the device, the first light-emitting unit emits red and green light, and the second light-emitting unit emits blue light. By obtaining a color, it is possible to obtain a light-emitting device that emits white light as a whole. In addition, examples of the configuration of a light-emitting device in which three or more light-emitting units are stacked include the following: The first light-emitting unit has a first blue light-emitting layer and the second light-emitting unit has a yellow or yellow-green light-emitting layer. The first light-emitting unit has a first color light-emitting layer and a second red light-emitting layer, and the third light-emitting unit has a second blue light-emitting layer. The tandem device may be a tandem device having the above-mentioned light-emitting device. As with the chair, white light can be obtained.

[0130] In addition, the above-mentioned EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and Each layer such as the charge generating layer and the electrodes can be formed by, for example, a deposition method (including a vacuum deposition method), a droplet discharge method (including an inkjet method), etc. It can be formed by using methods such as ink jet printing, coating, and gravure printing. They can be used in a wide range of applications, including low molecular weight materials, medium molecular weight materials (including oligomers and dendrimers), and or a polymeric material.

[0131] (Embodiment 3) In this embodiment, light emission using the light emitting device described in the first and second embodiments is performed. The apparatus will now be described.

[0132] In this embodiment, the light-emitting device described in the embodiment 1 and the embodiment 2 is used to manufacture The light-emitting device will be described with reference to FIG. 4. FIG. 4(A) shows the light-emitting device. FIG. 4(B) is a cross-sectional view taken along lines AB and CD in FIG. 4(A). The device includes a drive circuit section (source 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.

[0133] 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.

[0134] 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.

[0135] The element substrate 610 may be 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.

[0136] 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. The transistor may be a gate type transistor or a bottom gate type transistor. The semiconductor material is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and nitride. Gallium, etc., can be used. Alternatively, indium, such as In-Ga-Zn based metal oxides, Alternatively, an oxide semiconductor containing at least one of tungsten, gallium, and zinc may be used.

[0137] The crystallinity of the semiconductor material used in the transistor is not particularly limited. A semiconductor having crystallinity (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a partially crystalline region If a semiconductor having crystallinity is used, the transistor This is preferable because it can suppress deterioration of the star characteristics.

[0138] Here, in addition to the transistors provided in the pixels and the driver circuits, It is preferable to use an oxide semiconductor for a semiconductor device such as a transistor. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor with a wider band gap than silicon, the off-state of the transistor can be improved. This can reduce the current in the negative-going state.

[0139] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn). In-M-Zn oxides (where M is Al, Ti, Ga, Ge, Y, Zr, Sn, It is preferable that the oxide semiconductor contains an oxide represented by the formula (1) of La, Ce or Hf. This is more preferable.

[0140] Here, an oxide semiconductor that can be used in one embodiment of the present invention will be described. .

[0141] Oxide semiconductors are classified into single-crystal oxide semiconductors and other non-single-crystal oxide semiconductors. As a non-single crystal oxide semiconductor, for example, CAAC-OS (c-axis axially aligned oxide semiconductor) gned crystalline oxide semiconductor), polycrystalline Nanocrystalline oxide semiconductor, nc-OS iconductor), pseudo-amorphous oxide semiconductor (a-like OS:amorph amorphous-like oxide semiconductor, and amorphous oxide semiconductor Conductors, etc.

[0142] CAAC-OS has a c-axis orientation and multiple nanocrystals are connected in the ab-plane direction. The crystal structure has distortion. The distortion is caused by the area where multiple nanocrystals are connected. In the region, between a region with a uniform lattice arrangement and another region with a uniform lattice arrangement, Indicates the point where the direction is changing.

[0143] Nanocrystals are basically hexagonal, but are not limited to regular hexagons and may be non-regular hexagons. In addition, the distortion may have a lattice arrangement such as a pentagon or a heptagon. In addition, in the CAAC-OS, clear grain boundaries (grain boundaries) are not observed even in the vicinity of the strain. It is difficult to confirm the presence of the crystal grains due to the distortion of the lattice arrangement. This is because the CAAC-OS has a lattice structure in the ab-plane direction. The oxygen atoms are not densely packed, and the bond distance between atoms is shortened by the substitution of metal elements. This is because the distortion can be tolerated by changing the frequency band.

[0144] In addition, the CAAC-OS has a layer containing indium and oxygen (hereinafter, the In layer) and an element A layered crystal structure in which layers containing M, zinc, and oxygen (hereinafter referred to as the (M,Zn) layer) are stacked. Indium and element M tend to have a layered structure. It is possible, and when the element M in the (M,Zn) layer is replaced with indium, (In,M,Zn) Also, when the indium in the In layer is replaced with element M, (In,M ) layer.

[0145] CAAC-OS is a highly crystalline oxide semiconductor. Since it is difficult to confirm the grain boundaries, the decrease in electron mobility caused by the grain boundaries is unlikely to occur. In addition, the crystallinity of oxide semiconductors is degraded by the inclusion of impurities and the generation of defects. Therefore, CAAC-OS is designed to prevent impurities and defects (oxygen vacancies (V O :oxygen Therefore, CAA The physical properties of oxide semiconductors containing C-OS are stable. The oxide semiconductor has high heat resistance and high reliability.

[0146] The nc-OS is a nano-sized area (e.g., an area of ​​1 nm to 10 nm, especially 1 nm to 3 nm). The nc-OS has periodic atomic arrangement in the nanometer range. There is no regularity in the crystal orientation between the crystals. Therefore, no orientation is observed throughout the film. Therefore, depending on the analysis method, nc-OS may be considered to be a-like OS or amorphous oxide semiconductor. It may be indistinguishable from the above.

[0147] Note that indium, gallium, and zinc are used as a type of oxide semiconductor. In the case of IGZO, the nanocrystals mentioned above make it stable. In particular, IGZO tends to have difficulty growing crystals in air. , small crystals (e.g., For example, the nanocrystals mentioned above may be structurally more stable.

[0148] The a-like OS is an oxide semiconductor that has a structure between the nc-OS and the amorphous oxide semiconductor. Conductive. A-like OS has voids or low density regions. The ke-OS has a lower crystallinity than the nc-OS and CAAC-OS.

[0149] Oxide semiconductors have a variety of structures, each of which has different characteristics. Oxide semiconductors include amorphous oxide semiconductors, polycrystalline oxide semiconductors, a-like OS, and nc The compound may have two or more of -OS, CAAC-OS, and CAAC-OS.

[0150] In addition to the oxide semiconductors mentioned above, Cloud-Aligned Computing (CAC) osite)-OS may also be used.

[0151] CAC-OS is a material that has a conductive function in some parts and an insulating function in other parts. The material as a whole functions as a semiconductor. When used in the semiconductor layer of a material, the conductive function is to allow the electrons (or holes) that serve as carriers to flow. The function of insulation is to prevent the flow of electrons that act as carriers. The function of switching is achieved by making the function of switching and the function of insulating act in a complementary manner. On / Off function) can be added to CAC-OS. By separating the functions of each, the functions of both can be maximized.

[0152] The CAC-OS also has a conductive region and an insulating region. The insulating region has the above-mentioned insulating function. In some cases, the conductive and insulating regions are separated at the nanoparticle level. The conductive regions and the insulating regions may be unevenly distributed in the material. may be observed as a cloud-like formation with the edges blurred.

[0153] In addition, in CAC-OS, the conductive region and the insulating region are each 0.5 nm or more. When the particles are dispersed in the material with a size of 10 nm or less, preferably 0.5 nm to 3 nm, There is a match.

[0154] In addition, the CAC-OS is composed of components having different band gaps. For example, CAC-OS consists of a wide gap component originating from the insulating region and a conductive component originating from the conductive region. In this configuration, the carrier is When the carriers flow, the carriers mainly flow in the narrow gap component. The component with the gap acts complementary to the component with the wide gap to form a narrow gap. Carriers also flow into the component with a wide gap in conjunction with the component with a gap. When the CAC-OS is used in a channel forming region of a transistor, In the on-state, a high current drive capability, i.e., a large on-current, and a high field-effect mobility are obtained. It is possible.

[0155] That is, CAC-OS is a matrix composite. or metal matrix composite It can also be called.

[0156] By using the above-mentioned oxide semiconductor material for the semiconductor layer, the fluctuation of electrical characteristics is suppressed and reliability is improved. This makes it possible to realize highly reliable transistors.

[0157] In addition, the transistor having the above-described semiconductor layer can be used as a transistor due to its low off-state current. It is possible to hold the charge stored in the capacitor for a long period of time through such a transistor. By applying a transistor to each pixel, the gradation of the image displayed in each display area can be maintained while driving It is also possible to shut down the circuit. As a result, electronic devices with extremely low power consumption can be realized. It can be realized.

[0158] In order to stabilize the characteristics of the transistor, it is preferable to provide an undercoat film. Inorganic films such as silicon oxide film, silicon nitride film, silicon oxynitride film, and silicon nitride oxide film The insulating film can be formed in a single layer or a multilayer structure. CVD (Chemical Vapor Deposition) method (Plasma CVD method , thermal CVD method, MOCVD (Metal Organic CVD) method, etc.), ALD ( Formed using Atomic Layer Deposition (ALD), coating, printing, etc. It should be noted that the undercoat film does not have to be provided if it is not necessary.

[0159] The FET 623 indicates one of the transistors formed in the driver circuit section 601. The driving circuits are made up of various CMOS circuits, PMOS circuits, or NMOS circuits. In this embodiment, a driver integrated type in which a driver circuit is formed on a substrate is shown. However, this is not necessarily required, and the drive circuit can be formed externally instead of on the substrate. .

[0160] The pixel section 602 includes a switching FET 611, a current control FET 612 and its driver. The pixel is formed of a plurality of pixels including an anode 613 electrically connected to the drain. However, the present invention is not limited to this, and the pixel section may be formed by combining three or more FETs and a capacitive element.

[0161] An insulator 614 is formed to cover the end of the anode 613. It can be formed by using a photosensitive acrylic.

[0162] In order to improve the coverage of the EL layer and the like to be formed later, the upper end of the insulator 614 is For example, the material of the insulator 614 is When a positive photosensitive acrylic is used, the radius of curvature (0. It is preferable that the insulating material 614 has a curved surface having a thickness of 2 μm to 3 μm. Either a negative-type photosensitive resin or a positive-type photosensitive resin can be used.

[0163] An EL layer 616 and a cathode 617 are formed on the anode 613. It is preferable to use a material having a large work function for the anode 613. For example, ITO film, or silicon-containing indium tin oxide film, 2 to 20 wt% oxide Indium oxide film containing zinc, titanium nitride film, chromium film, tungsten film, Zn film, Pt In addition to single-layer films such as titanium nitride films, laminated films of titanium nitride and aluminum-based films, A three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film can be used. In addition, the multilayer structure has low wiring resistance and good ohmic contact. It can also function as an anode.

[0164] The EL layer 616 is formed by deposition using a deposition mask, inkjet printing, or spin coating. The EL layer 616 is formed by the method described in the first and second embodiments. The EL layer 616 may include other materials such as: It may be a low molecular weight compound or a high molecular weight compound (including oligomers and dendrimers). .

[0165] Furthermore, the material used for the cathode 617 formed on the EL layer 616 is a material having a small work function. Materials that are suitable for use in the manufacture of semiconductors include Al, Mg, Li, Ca, and their alloys and compounds (MgAg, MgIn, It is preferable to use AlLi, etc. In the case of transmitting light, the cathode 617 is made of a thin metal film and a transparent conductive film (I TO, indium oxide containing 2-20wt% zinc oxide, indium tin containing silicon It is preferable to use a laminate of a metal oxide such as zinc oxide (ZnO).

[0166] The anode 613, the EL layer 616, and the cathode 617 form a light-emitting device. The light emitting device is the light emitting device described in the first and second embodiments. The pixel portion is formed with a plurality of light-emitting devices. The device includes the light-emitting device according to the first and second embodiments and other components. The light emitting device may include both a light emitting device having a light emitting diode and a light emitting device having a light emitting diode.

[0167] Furthermore, the sealing substrate 604 is bonded to the element substrate 610 with a sealant 605, A light emitting device is placed in a space 607 surrounded by a child substrate 610, a sealing substrate 604, and a sealant 605. The structure is provided with a chair 618. The space 607 is filled with a filling material. In some cases, the gas is filled with an inert gas (nitrogen, argon, etc.), and in other cases, it is filled with a sealing material. By forming a recess in the sealing substrate and providing a desiccant there, deterioration caused by moisture can be prevented. This is a preferable configuration because it is possible to suppress the degradation.

[0168] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is desirable that these materials are as impermeable to moisture and oxygen as possible. Materials used for the sealing substrate 604 include glass substrates, quartz substrates, and FRP (Fiber Reinforced Plastics). reinforced plastics), PVF (polyvinyl fluoride), polyester A plastic substrate made of, for example, polyester or acrylic can be used.

[0169] Although not shown in FIG. 4, a protective film may be provided on the cathode. The protective film may be an organic resin film or an inorganic A protective film may be formed so as to cover the exposed portion of the sealant 605. The protective film may be formed on the front and side surfaces of the pair of substrates, the sealing layer, the insulating layer, It can be provided to cover the exposed sides of the above.

[0170] The protective film can be made of a material that is difficult for impurities such as water to permeate. It is possible to effectively suppress the diffusion of impurities such as those mentioned above from the outside to the inside.

[0171] The materials that make up the protective film include oxides, nitrides, fluorides, sulfides, ternary compounds, and metals. Alternatively, polymers and the like can be used, for example, aluminum oxide, hafnium oxide, hafnium oxide, etc. Funium 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 oxide Materials containing hafnium, aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, etc. Materials, nitrides containing titanium and aluminum, oxides containing titanium and aluminum , oxides containing aluminum and zinc, sulfides containing manganese and zinc, cerium and and sulfides containing strontium, oxides containing erbium and aluminum, yttrium Materials including, for example, oxides containing lithium and zirconium can be used.

[0172] The protective film should be formed using a film formation method that provides good step coverage. One such technique is atomic layer deposition (ALD). The ALD method can be used to form a protective It is preferable to use the ALD method for films that are dense and free of cracks and pinholes. It is possible to form a protective film having reduced defects or a uniform thickness. Damage to the processed member when forming the protective film can be reduced.

[0173] For example, by forming a protective film using the ALD method, it is possible to fabricate a surface with complex unevenness or a touch panel. It is possible to form a uniform protective film with few defects on the top, sides and back of the panel. .

[0174] 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.

[0175] 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.

[0176] In FIG. 5, a light-emitting device that emits white light is formed, and a colored layer (color filter) is provided. FIG. 5A 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.

[0177] In addition, in FIG. 5(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 on which a colored layer and a black matrix are provided. The colored layer and the black matrix are fixed to the substrate 1001. The substrate 1035 is covered with an overcoat layer 1036. The light is emitted from the light-emitting layer without passing through the colored layers, and the light is emitted from the light-emitting layer without passing through the colored layers. The light that does not pass through the colored layer is white, and the light that passes through the colored layer is red, green, or blue. This means that images can be expressed using four color pixels.

[0178] In FIG. 5B, the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer An example in which a layer (1034B) is formed between the gate insulating film (1003) and the first interlayer insulating film (1020) In this way, the colored layer is provided between the substrate 1001 and the sealing substrate 1031. is also good.

[0179] In the light emitting device described above, the light is taken in toward the substrate 1001 on which the FET is formed. The light emitting device has a bottom emission structure, but the light is taken in from the sealing substrate 1031 side. The light emitting device may have a structure in which the light is emitted from the top (top emission type). A cross-sectional view of a light-emitting device is shown in FIG. 6. In this case, a substrate 1001 that does not transmit light is used. The bottom is not connected to the FET and the anode of the light-emitting device until the connection electrode is fabricated. The third interlayer insulating film 1037 is then formed in the same manner as in the case of the m-emission type light emitting device. The insulating film is formed to cover the electrode 1022. This insulating film may also serve as a planarizing film. The interlayer insulating film 1037 may be formed using the same material as the second interlayer insulating film, or other known materials. It is possible.

[0180] The anodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are the anodes here. However, it may be formed as a cathode. In the case of an optical device, it is preferable that the anode is a reflective electrode. The EL layer 103 has the same structure as that described in the first and second embodiments, and In addition, the device structure is designed to obtain white light emission.

[0181] In the top emission structure shown in Fig. 6, the colored layers (red colored layer 1034R, green colored layer The sealing is performed by using a sealing substrate 1031 provided with a blue color layer 1034G and a blue color layer 1034B. The sealing substrate 1031 has a black matrix disposed between the pixels. A coloring layer (a red coloring layer 1034R, a green coloring layer 1034G, The blue colored layer (1034B) and the black matrix are covered with an overcoat layer. Note that the sealing substrate 1031 is a substrate having a light-transmitting property. In this example, a full-color display using four colors, red, green, blue, and white, is shown. However, the present invention is not limited to this. A full color display may be achieved using four colors, yellow, green, and blue, or three colors, red, green, and blue.

[0182] In a top emission type light emitting device, a microcavity structure can be suitably applied. Light-emitting devices with a microcavity structure use an anode as a reflective electrode and a cathode as a semi-transparent / semi-reflective electrode. The reflective electrode and the semi-transmissive / semi-reflective electrode are separated by at least The device has an EL layer, and at least has a light-emitting layer which becomes a light-emitting region.

[0183] The reflectance of the reflective electrode for visible light is 40% to 100%, preferably 70% to 100%. %, and its resistivity is 1×10 -2 The film is assumed to be less than Ωcm. The semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%. , and its resistivity is 1×10 -2 It is assumed that the film has a resistance of less than Ωcm.

[0184] The light emitted from the light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transparent and semi-reflective electrode. The light is reflected and resonates.

[0185] The light-emitting device is configured by changing the thickness of the transparent conductive film, the composite material, the carrier transport material, etc. By adjusting the thickness of the reflective electrode, the optical distance between the reflective electrode and the semi-transmissive and semi-reflective electrode can be changed. This strengthens the light of the resonating wavelength between the reflective electrode and the semi-transparent and semi-reflective electrode, and resonates. It can attenuate light of wavelengths that are not

[0186] The light reflected by the reflective electrode and returned (first reflected light) is semi-transmitted from the light emitting layer. The light that is directly incident on the semi-reflective electrode (first incident light) interferes greatly with the reflective electrode. The optical path length of the light-emitting layer is (2n-1)λ / 4 (where n is a natural number greater than or equal to 1, and λ is the amplified It is preferable to adjust the optical distance to a wavelength that is suitable for the first emission. By matching the phase of the reflected light with that of the first incident light, the light emitted from the light-emitting layer can be amplified. do.

[0187] In the above configuration, even if the EL layer has a plurality of light-emitting layers, a single light-emitting For example, the above-mentioned tandem light-emitting device may be combined with the above-mentioned structure. In addition, multiple EL layers are provided in one light-emitting device with a charge generating layer sandwiched between them, and each EL The layer may be formed with one or more light-emitting layers.

[0188] The microcavity structure makes it possible to enhance the emission intensity of a specific wavelength in the forward direction. This allows for low power consumption. In the case of a light-emitting device that displays images using a single pixel, the yellow light emission not only improves brightness, but also Since a microcavity structure that matches the wavelength of each color can be applied, it is possible to produce light-emitting devices with excellent characteristics. It can be placed.

[0189] 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.

[0190] So far, we have explained about active matrix type light emitting devices. From now on, we will discuss passive type light emitting devices. A passive matrix type light emitting device will be described. 7A is a perspective view showing the light-emitting device, and FIG. FIG. 7B is a cross-sectional view taken along the line XY of FIG. 7A. In FIG. 7, the substrate 951 has: An EL layer 955 is provided between the electrode 952 and the electrode 956. It is covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 become thinner between one side wall and the other side wall as they approach the substrate surface. In other words, the cross section of the partition layer 954 in the short side direction is The bottom side (the side that faces the same direction as the surface direction of the insulating layer 953 and is in contact with the insulating layer 953) ) is the upper side (the side that faces in the same direction as the surface direction of the insulating layer 953 and does not contact the insulating layer 953). In this way, by providing the partition layer 954, the light emitting device caused by static electricity or the like can be prevented from being damaged. In addition, the present invention can be applied to a passive matrix type light emitting device. The light emitting device according to the first embodiment and the second embodiment is used, and the light emitting device has high reliability. It is possible to provide a light emitting device with low power consumption.

[0191] The light emitting device described above is a device that includes a large number of minute light emitting devices arranged in a matrix. Since it is possible to control each of these, it can be suitably used as a display device for displaying images. It is a light-emitting device.

[0192] This embodiment mode can be freely combined with other embodiment modes.

[0193] (Embodiment 4) In this embodiment, the light-emitting device according to any one of the first and second embodiments is used as a lighting device. An example of using the lighting device as a light source will be described with reference to FIG. 8. FIG. 8(B) is a top view of the lighting device, and FIG. FIG. 8A is a cross-sectional view taken along line ef in FIG. 8B.

[0194] The lighting device in this embodiment has an anode 4 on a light-transmitting substrate 400 serving as a support. The anode 401 corresponds to the anode 101 in the second embodiment. When light is extracted from the anode 401 side, the anode 401 is formed from a light-transmitting material.

[0195] A pad 412 for supplying a voltage to the cathode 404 is formed on the substrate 400 .

[0196] An EL layer 403 is formed on the anode 401. The EL layer 403 is the same as that in the first embodiment and the second embodiment. The configuration of the EL layer 103 in the second embodiment, or the light-emitting units 511, 512 and the charge generation This corresponds to a configuration in which the layer 513 is combined. For details of these configurations, refer to the relevant description. I want to be.

[0197] A cathode 404 is formed to cover the EL layer 403. The cathode 404 is the same as the cathode 1 in the second embodiment. When light is emitted from the anode 401 side, the cathode 404 is made of a material with high reflectivity. The cathode 404 is connected to a pad 412, which supplies a voltage to the cathode 404. can be.

[0198] As described above, the light-emitting device having the anode 401, the EL layer 403, and the cathode 404 is The lighting device has a high light emitting efficiency. Therefore, the lighting device in this embodiment can be a lighting device with low power consumption.

[0199] The substrate 400 on which the light emitting device having the above-mentioned configuration is formed is sealed with a sealing substrate 407. The lighting device is completed by fixing and sealing using sealing materials 405 and 406. Either one of 405 and 406 may be used. Also, the inner seal material 406 (FIG. 8(B) ) (not shown) can also be mixed with a desiccant, which absorbs moisture in the space 408. This leads to improved reliability.

[0200] In addition, a part of the pad 412 and the anode 401 is extended outside the sealing materials 405 and 406. By doing so, it can be used as an external input terminal. An IC chip 420 or the like may be provided.

[0201] As described above, the lighting device according to the present embodiment has the EL element according to the first and second embodiments. The light emitting device described above is used to provide a light emitting device with good reliability. A light emitting device with low power consumption can be provided.

[0202] (Embodiment 5) In this embodiment, the light emitting device according to the first and second embodiments is used as a part of the light emitting device. An example of an electronic device including the light-emitting device according to the first embodiment and the second embodiment will be described. The device has a long life and is a highly reliable light-emitting device. The electronic device described in the above can be an electronic device having a light emitting section with good reliability.

[0203] As an example of an electronic device to which the light-emitting device is applied, a television set (television, (also called television receivers), computer monitors, digital cameras, digital digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices) (hereinafter referred to as "computer games"), portable game machines, personal digital assistants, audio playback devices, large game machines such as pachinko machines Specific examples of these electronic devices are shown below.

[0204] FIG. 9A shows an example of a television device. The television device includes a housing 710. A display unit 7103 is built into the display unit 1. Also, in this embodiment, a stand 7105 is used to support the display unit 1. The display unit 7103 can display images. The display portion 7103 can display the light-emitting device described in Embodiments 1 and 2. The electrodes are arranged in a matrix.

[0205] The television device can be operated using an operation switch provided on the housing 7101 or a separate remote control. The remote control device 7110 includes an operation key 7109. This allows you to control the channel and volume, and the image displayed on the display unit 7103 In addition, the remote control operation device 7110 can be operated. A display portion 7107 for displaying information output from the image forming apparatus may be provided.

[0206] The television set is assumed to be equipped with a receiver and a modem. It can receive television broadcasts and can also communicate by wire or wirelessly via a modem. By connecting to a network, communication can be one-way (sender to receiver) or two-way (sender to It is also possible to communicate information between the sender and the recipient, or between the recipients themselves.

[0207] FIG. 9(B1) shows a computer, which includes a main body 7201, a housing 7202, a display unit 7203, and a keyboard. keyboard 7204, external connection port 7205, pointing device 7206, etc. In addition, the computer is configured to read the light-emitting device according to the first and second embodiments. The display portion 7203 is fabricated by arranging the liquid crystal display panels in a matrix. The computer may be in the form shown in FIG. 9(B2). The second display unit 7206 is used instead of the keyboard 7204 and the pointing device 7206. The second display unit 7210 is a touch panel type. The input display on the display unit 7210 is operated with a finger or a special pen to input data. In addition, the second display portion 7210 can be used not only for input display but also for other displays. The display unit 7203 may also be a touch panel. The two screens are connected by a hinge, which prevents the screen from being scratched when storing or transporting the device. This can also prevent problems such as damage to the device.

[0208] FIG. 9C shows an example of a mobile terminal. The mobile phone is built in a housing 7401. In addition to the display unit 7402, the operation buttons 7403, the external connection port 7404, the speaker 740 5, a microphone 7406, etc. The mobile phone is the same as that in the first embodiment and the second embodiment. A display unit 7402 in which the light-emitting devices according to embodiment 2 are arranged in a matrix is ​​provided. is.

[0209] In the mobile terminal shown in FIG. 9C, information is input by touching the display portion 7402 with a finger or the like. In this case, the user can make a call or write an email. An operation such as pressing a key or the like can be performed by touching the display portion 7402 with a finger or the like.

[0210] The screen of the display unit 7402 has three main modes. The first is a display mode that is mainly used for displaying images. The first mode is a display mode, the second is an input mode for inputting information such as characters, and the third mode is a display mode. This is a display + input mode that combines the display mode and the input mode.

[0211] For example, when making a call or composing an e-mail, the display unit 7402 is used to input characters. The main character input mode is to input characters displayed on the screen. It is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402. I wish.

[0212] In addition, the mobile terminal may include a sensor for detecting the inclination, such as a gyro or an acceleration sensor. By providing a device, the orientation of the mobile terminal (vertical or horizontal) can be determined and the screen display of the display portion 7402 can be displayed. The display can be switched automatically.

[0213] The screen mode can be changed by touching the display portion 7402 or by operating the housing 7401. This is done by operating the button 7403. Also, depending on the type of image displayed on the display unit 7402, For example, the image signal to be displayed on the display unit is a moving image. If it is data, the mode is switched to display mode, and if it is text data, the mode is switched to input mode.

[0214] In the input mode, the optical sensor of the display unit 7402 detects a signal and displays If there is no input by touch operation of the part 7402 for a certain period of time, the screen mode is changed to the input mode. Alternatively, the display mode may be switched from the normal mode to the display mode.

[0215] The display portion 7402 can also function as an image sensor. By touching the palm or fingers of the user on the sensor 02 and capturing an image of the palm print or fingerprint, the user can be authenticated. In addition, a backlight that emits near-infrared light to the display unit or a sensing light that emits near-infrared light By using a source, it is also possible to image finger veins, palm veins, etc.

[0216] Note that the configuration shown in this embodiment mode is a combination of the configurations shown in Embodiment Modes 1 to 4. They can be used in combination.

[0217] As described above, the light emitting device according to the first and second embodiments can be used in the light emitting apparatus. The range of applications is extremely wide, and this light-emitting device can be applied to electronic devices in a wide range of fields. By using the light emitting devices according to the first and second embodiments, the reliability of the light emitting devices is improved. You can get high quality electronic equipment.

[0218] FIG. 10A is a schematic diagram showing an example of a cleaning robot.

[0219] The cleaning robot 5100 has a display 5101 arranged on the top surface and multiple The camera 5102, the brush 5103, and the operation button 5104 are also shown. However, the underside of the cleaning robot 5100 is provided with tires, a suction port, etc. The robot 5100 also has an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezo sensor, It is equipped with various sensors such as a sensor, a light sensor, and a gyro sensor. 100 is equipped with wireless communication means.

[0220] The cleaning robot 5100 moves by itself, detects dirt 5120, and sucks it out from the suction port on its bottom. It can suck up dirt.

[0221] In addition, the cleaning robot 5100 analyzes the image captured by the camera 5102 and detects walls, furniture, or It can detect obstacles such as steps. It can also detect wiring and other obstacles by image analysis. If an object that is likely to get tangled in the brush 5103 is detected, the rotation of the brush 5103 can be stopped. can.

[0222] The display 5101 can display the remaining battery level, the amount of dirt sucked up, etc. The route traveled by the cleaning robot 5100 can be displayed on the display 5101. In addition, the display 5101 may be a touch panel, and the operation buttons 5104 may be a display. It may be provided in the ray 5101.

[0223] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. The images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the Cleaning Robot 5100 can check the state of the room even when he / she is away from home. In addition, the display on the display 5101 can be displayed on a mobile electronic device such as a smartphone. You can also check it out at.

[0224] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0225] The robot 2100 shown in FIG. 10(B) includes a computing device 2110, an illuminance sensor 2101, A microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, It is equipped with a lower camera 2106, an obstacle sensor 2107, and a movement mechanism 2108.

[0226] The microphone 2102 has a function of detecting the user's voice and environmental sounds. The speaker 2104 has a function of emitting sound. The user can communicate with the computer using the computer 2102 and the speaker 2104. It is possible.

[0227] The display 2105 has a function of displaying various information. It is possible for the user to display desired information on the display 2105. The display 2105 may be equipped with a touch panel. The information terminal may be a terminal that can be used for charging and discharging the battery. and enables data transfer.

[0228] The upper camera 2103 and the lower camera 2106 are used to capture images of the surroundings of the robot 2100. The obstacle sensor 2107 detects the obstacles of the robot 210 using the moving mechanism 2108. When the robot 21 moves forward, it can sense the presence or absence of obstacles in its path. 00 uses an upper camera 2103, a lower camera 2106, and an obstacle sensor 2107. The light-emitting device according to one embodiment of the present invention can recognize the surrounding environment and move safely. It can be used for the display 2105.

[0229] FIG. 10C is a diagram showing an example of a goggle-type display. Goggle-type display For example, the device includes a housing 5000, a display unit 5001, a speaker 5003, and an LED lamp 5004. , connection terminal 5006, sensor 5007 (force, displacement, position, speed, acceleration, angular velocity, rotation speed ,distance, light, liquid, magnetic, temperature, chemical, sound, time, hardness, electric field, current, voltage, power, (including functions to measure radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), The microphone 5008, the display unit 5002, the support unit 5012, the earphones 5013, etc. .

[0230] The light-emitting device according to one embodiment of the present invention can be used for the display portion 5001 and the display portion 5002. .

[0231] FIG. 11 shows a configuration of the light-emitting device according to the first and second embodiments, which is a lighting device. The desk lamp shown in FIG. 11 is an example of a desk lamp using the same. 02, and the lighting device described in the third embodiment may be used as the light source 2002.

[0232] FIG. 12 shows a configuration of the light-emitting device according to the first and second embodiments, which is installed in a lighting device 3 in a room. 001. The light-emitting devices described in the first and second embodiments are Since the light emitting device is highly reliable, it can be used as a highly reliable lighting device. Since the light-emitting devices described in the first and second embodiments can be made large in area, It can be used as a large-area lighting device. The light-emitting device described is thin and can be used as a thin lighting device. become.

[0233] The light emitting devices according to the first and second embodiments can be used for automobile windshields, The embodiment 1 and the embodiment 2 can be mounted on a flash board. FIG. 1 shows an embodiment in which the light emitting device is used on the windshield or dashboard of an automobile. The display areas 5200 to 5203 are the light-emitting devices described in Embodiments 1 and 2. The display area is provided using a device.

[0234] In this embodiment, the display area 5200 and the display area 5201 are provided on the windshield of a car. A display device incorporating the light-emitting device according to the first and second embodiments. In the light-emitting device described in the second embodiment, the anode and the cathode are made of light-transmitting electrodes. This allows the display device to be in a see-through state, where the other side can be seen through. Yes, you can. If the display is see-through, even if it is installed on the windshield of a car, It can be installed without obstructing the view. When a transistor is provided, an organic transistor made of an organic semiconductor material or a transistor made of an oxide semiconductor is used. A light-transmitting transistor such as a transistor having a light-transmitting property is preferably used.

[0235] The display area 5202 is a display device according to the first and second embodiments provided in a pillar portion. The display device is equipped with an optical device. The display area 5202 includes an imaging device provided on the vehicle body. By projecting images from the steps, it is possible to compensate for the view obstructed by the pillars. Similarly, the display area 5203 provided on the dashboard is not blocked by the vehicle body. By projecting images from an imaging device installed on the outside of the vehicle, the driver can see the blind spots. This can enhance safety by projecting images to complement the invisible parts. This allows the driver to check for safety more naturally and without any discomfort.

[0236] The display area 5203 can provide various information. The display can be adjusted to suit the user's preferences. The display items and layout can be changed as needed. This information is displayed in the display area 5 The display areas 5200 to 5202 may also be provided. Area 5203 can also be used as a lighting device.

[0237] 14(A) and (B) show a foldable mobile information terminal 5150. The foldable mobile information terminal 5150 includes a housing 5151, a display area 5152, and a bending portion 515. FIG. 14(A) shows the portable information terminal 5150 in an unfolded state. Fig. 5B) shows the portable information terminal in a folded state. The portable information terminal 5150 has a large display area. Despite having a range of 5152, it folds up compactly and is highly portable.

[0238] The display area 5152 can be folded in half by the bend 5153. 3 is composed of an expandable member and multiple support members, and when folding, the expandable The member is stretched, and the bent portion 5153 has a radius of curvature of 2 mm or more, preferably 3 mm or more. It can be folded.

[0239] The display area 5152 is a touch panel (input / output) equipped with a touch sensor (input device). The light-emitting device according to one embodiment of the present invention can be used in the display region 5152. Cut.

[0240] 15(A) to (C) show a foldable portable information terminal 9310. FIG. 15(A) shows a portable information terminal 9310 in an unfolded state. FIG. 15(B) shows a portable information terminal 9310 in an unfolded state or A portable information terminal 9310 is shown in a folded state changing from one to the other. FIG. 15C shows the portable information terminal 9310 in a folded state. The foldable design is highly portable and unfolds for a seamless, large viewing area. This provides excellent visibility of the display.

[0241] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. The display panel 9311 is a touch panel equipped with a touch sensor (input device). The display panel 9311 may be a display panel (input / output device). The portable information terminal 9310 is in an unfolded state by bending the two housings 9315. The light-emitting device according to one embodiment of the present invention can be reversibly transformed from a folded state to a folded state. It can be used for the display panel 9311. EXAMPLES

[0242] In this example, a light-emitting device 1 according to an embodiment of the present invention and a comparative light-emitting device 1 were fabricated. The fabrication method and impedance spectroscopy measurement results are described below. The structural formula of the organic compound used in step 1 is shown below.

[0243] [ka]

[0244] (Method of fabricating light-emitting device 1) 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.

[0245] 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.

[0246] 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.

[0247] Next, the substrate on which the anode 101 is formed is placed in a straight line 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-phenyl represented by the above structural formula (i) was obtained by the above deposition method. Benzo[b]naphtho[1,2-d]furan-8-amine (BBABnf) and AL D-MP001Q (Bunseki Kobo Co., Ltd., Material serial number: 1S20180314) , 10n The hole injection layer 111 was formed by co-evaporation of the acceptor. It is an organic compound that has the following properties.

[0248] Next, on the hole injection layer 111, BBABnf was deposited at 20 After that, a second hole transport layer 112-2 having a thickness of 1 nm was deposited by vapor deposition of a compound represented by the above structural formula (ii). Represented by 3,3'-(naphthalene-1,4-diyl)bis(9-phenyl-9H-carbazone) A hole transport layer 112 is formed by depositing PCzN2 (abbreviation: PCzN2) to a thickness of 10 nm. The second hole transport layer 112-2 also functions as an electron blocking layer.

[0249] Next, 9-(1-naphthyl)-10-[4-(2-naphthyl)-1-propanol represented by the above structural formula (iii) αN-βNPAnth) and (iv) 3,10-Bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenyl Amino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA 2Nbf(IV)-02) in a weight ratio of 1:0.015 (=αN-βNPAnth:3, 10PCA2Nbf(IV)-02) was co-evaporated to form the light-emitting layer 113 at 25 nm. Successful.

[0250] Thereafter, on the light-emitting layer 113, 2-{4-[9,10-di(naphthalene) phthalen-2-yl)-2-anthryl]phenyl}-1-phenyl-1H-benzoimide dazole (abbreviation: ZADN) and 8-hydroxyquinolinate represented by the above structural formula (vi) - Lithium (abbreviation: Liq) (manufactured by Chemipro Chemicals (serial number: 181201)) After co-evaporating 12.5 nm of ZADN to a ratio of 0.7:1 (=ZADN:Liq), 1:0.7 (=ZADN:Liq) was co-evaporated to a thickness of 12.5 nm to form an electron transport layer 11 4 was formed.

[0251] After the electron transport layer 114 is formed, Liq is evaporated to a thickness of 1 nm to form an electron injection layer 1 Then, aluminum is evaporated to a thickness of 200 nm to form a cathode. 102 was formed to fabricate the light emitting device 1 of this example.

[0252] (Method of producing comparative light-emitting device 1) In the comparative light-emitting device 1, αN-βNPAnth in the light-emitting layer 113 is represented by the above structural formula (vi i) 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzyl The electron transport layer 114 was then formed on the substrate 111. 2-[3'-(dibenzothiophene-4-yl)biphenyl]- ... nyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II After evaporating 15 nm of 2,9-di(2-naphthyl)- 4,7-Diphenyl-1,10-phenanthroline (abbreviation: NBPhen) was evaporated to 10 nm. The light-emitting device was fabricated in the same manner as the light-emitting device 1, except that the electrode was deposited on the substrate.

[0253] The device structures of light-emitting device 1 and comparative light-emitting device 1 are summarized in the table below.

[0254] [Table 3]

[0255] Here, the HOMO level, LUMO level and electric field strength [ The table below summarizes the electron mobility at a square root of 600 V / cm.

[0256] [Table 4]

[0257] 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 the characteristics of the light-emitting device 1 were measured. The measurements were performed at room temperature. Reference luminescence device 1: 1000cd / m 2 The main characteristics of the area are shown in Table 5.

[0258] [Table 5]

[0259] As shown in Table 5, the light-emitting device 1 according to one embodiment of the present invention and the comparative light-emitting device 1 have good initial It was found to be a blue light-emitting device with novel properties.

[0260] 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. 20, a light-emitting device 1 according to one embodiment of the present invention is After the device is driven, the luminance rises and becomes higher than the initial luminance, and then gradually decreases. In other words, the degradation curve has a maximum point. This significantly improves the operating lifespan based on a low degradation condition of 2 to 5%. came.

[0261] Next, impedance spectroscopy measurements (IS measurements) were performed on the light-emitting device 1 and the comparative light-emitting device 1. A small sinusoidal voltage signal [V = V0exp(iωt)] was applied to the light-emitting device. The amplitude of the response current signal [I=I0exp{i(ωt+φ)}] and the position of the input signal are The impedance (Z=V / I) was calculated from the phase difference. By applying a voltage to the element, it is possible to separate the components with different relaxation times that contribute to the impedance. , can be measured.

[0262] The frequency of the applied voltage signal is used as a parameter, and the obtained impedance is displayed on the complex plane. The result is called a Nyquist plot. Calculate the fundamental transfer functions, such as admittance (Y), modulus (M), and dielectric constant (ε), etc. It is possible.

[0263] In this example, the impedance (Z) plot shows the resistance component on the real axis, and the capacitance component on the real axis. The light-emitting devices were analyzed using modulus (M) plots, which show the reciprocal of the modulus.

[0264] Measurements were performed using Biologic's SP-300 Advanced high-performance electrochemical measurement system. The test was performed using a cable for measuring minute currents on the test model.

[0265] The Z plots of the light-emitting device 1 and the comparative light-emitting device 1 are shown in Figures 21(A) and 21(B). 21(A) and (B) are in the frequency range of 1 MHz to 3 MHz, AC voltage of 100 mV, and applied voltage The measurement was performed with a voltage of 2.5 V. The driving time of the element after driving was 1 is 50mA / cm 2 The light-emitting device 1 was used for 670 hours, and the comparative light-emitting device 2 was used for 380 hours. .

[0266] As shown in FIG. 21A, the light-emitting device 1 according to one embodiment of the present invention has a characteristic that the device after being driven is different from the device before being driven. It can be seen that the resistance is smaller than that of the conventional light-emitting device. As shown in Figure 21(B), the resistance of the device after driving is slightly higher than that of the device before driving. I found out it was getting bigger.

[0267] Also, in Fig. 22, the current density is 50mA / cm 2 Voltage vs. operating time under certain conditions As shown in FIG. 22, the light-emitting device 1, which is a light-emitting device of one embodiment of the present invention, When the current density was constant, the driving voltage decreased. The results are consistent with the IS measurements, which suggest a decrease in resistance.

[0268] In addition, the driving voltage of the comparative light-emitting device 1, which is a conventional element, increases with driving. This result was consistent with the IS measurement. Under conditions of constant density, the driving voltage generally tends to increase with driving. The decrease in driving voltage during driving is a characteristic phenomenon of the light-emitting device according to one embodiment of the present invention. .

[0269] Next, the M plot of the light-emitting device 1 is shown in FIG. 23. The graph shape before driving and after driving It was found that the shape was different and the modulus changed before and after driving.

[0270] Next, we used the equivalent circuit analysis software ZView (Scribner Associates) The fitting was done by Scribner Associates (USA) and the luminescence device was The equivalent circuit of the device can be expressed as four RC parallel circuits and one series resistor, as shown in Figure 18. It was found that this was possible. The values ​​in the M plot are the equivalences separated by fitting. This shows where the resistive component of the valence circuit appears.

[0271] Next, FIG. 19 shows a graph in which the values ​​of the separated resistance components before and after driving are plotted. From this, it can be seen that only the resistance of R2 after driving is reduced by more than one order of magnitude compared to the resistance before driving. mosquito I did.

[0272] Therefore, it is necessary to determine which layer of the light-emitting device 1 each of these resistance components corresponds to. Light-emitting devices (light-emitting devices 2 to 8) were fabricated with different thicknesses of the layers. The results were confirmed by measuring the electron transport layer 114. The structure is the same as that of the light-emitting device 1, except for the thicknesses of the parts shown in bold in the table below. Regarding the electron transport layer 114, the electron transport layer 114 of the light emitting device 1 has a thickness of 12.5 n A first electron transport layer 114-1 of 12.5 nm ZADN:Liq (=0.7:1) and a second electron transport layer 114-2 of 12.5 nm The second electron transport layer 114-2 had a laminated structure of ZADN:Liq (=1:0.7). The light-emitting devices 2 to 8 have wavelengths of 25 nm, 35 nm, 45 nm, and 55 nm. It is formed of one layer of ZADN:Liq (=1:1).

[0273] [Table 6]

[0274] The IS measurements were performed on the light-emitting devices 2 to 8, and the M The plots are shown in Figures 24 to 26. Light-emitting devices with different thicknesses of the electron transport layer 114 FIG. 24(A) shows the M plots of the light-emitting devices 3 to 5 and the reference light-emitting device 2. In addition, the thickness of the light-emitting layer 113 is changed in the light-emitting device 6 and the light-emitting device 7, and the reference FIG. 25(A) shows the M plot of the light-emitting device 2, which is an example of the first hole transport layer 112-1. The M plots for the light-emitting device 8 with different thicknesses and the reference light-emitting device 2 are shown. Shown in Figure 26(A).

[0275] As shown in FIG. 24(A) to FIG. 26(A), the M plot It can be seen that the shape of each light-emitting device also changes. The resistance of the sensor is expressed as the resistance component R Plots are made for R1 to R5.

[0276] 24 to 26, in the light-emitting device in which the film thickness of the electron transport layer 114 is changed, In the light-emitting device in which the thickness of the light-emitting layer 113 is changed, the resistance component of R1 is In the light-emitting device in which the thickness of the hole transport layer 112-1 is changed, the resistance component of R3 is From this, it can be seen that the light-emitting device according to one embodiment of the present invention shown in FIG. In the equivalent circuit, R1 is the light-emitting layer, R2 is the electron transport layer, and R3 is the first hole transport layer. It was found that the remaining R4 was the second hole transport layer.

[0277] From the above, the resistance component R2, whose resistance changes before and after driving, is the component originating from the electron transport layer 114. It was found to be the case.

[0278] Thus, the light-emitting device 1 according to one embodiment of the present invention has a long life. a light-emitting device in which the resistance of the entire light-emitting device is lower after the device is driven than before the device is driven It was also found that the decrease in resistance was due to a decrease in the resistance of the electron transport layer 114. I found out that this is something that can be done.

[0279] From these results, the resistance value of the electron transport layer 114 of the light-emitting device 1 decreases when the device is driven. As a result, carriers (electrons) flow more easily, and the flow spreads to a part of the electron transport layer 114. The end of the recombination region moves toward the light-emitting region. This allows the electron transport layer to contribute to light emission. This makes it possible to convert the recombination energy that would otherwise be lost into light without any need for Therefore, it is considered that an increase in luminance occurs as shown in FIG.

[0280] In this manner, the light-emitting device of one embodiment of the present invention can have a long lifetime. can. EXAMPLES

[0281] In this embodiment, a current-carrying (driving a light-emitting device) that can be used for the electron transport layer 114 is An example of a material whose resistance value decreases when it is subjected to electrical stimulation will be described below.

[0282] The material whose resistance value decreases when a current is passed through it is an alkali metal or an alkaline earth metal. A metal-organic complex or an organic compound with electron transport properties and an alkali metal or alkali metal complex are used. A mixed material of an alkali earth metal and an organometallic complex can be preferably used. As an organic compound having electron transport properties, 2-phenyl-3-{4-[10-(3-pyridinyl) (9-anthryl)phenyl)quinoxaline (abbreviation: PyA1PQ), alkali metal Or the calculation results for the case where Liq is used as an organometallic complex of an alkaline earth metal show.

[0283] First, in a film in which PyA1PQ and Liq were mixed in a weight ratio of 1:1, The ease of polymer formation was calculated using classical molecular dynamics. Specifically, the weight ratio was adjusted to 1:1. Then, place the molecules in the cell so that the molar ratio of PyA1PQ and Liq is 18:82. After compressing the cell at high temperature and pressure, the pressure is reduced to atmospheric pressure and the temperature is lowered to room temperature. By lowering the temperature, the cells are relaxed, and the model is in an amorphous state. After that, the condensation state of the molecules in the cell was confirmed, and it was found to be dimers and trimers of Liq. From this, it is possible to identify the clusters of hexamers and aggregates of hexamers. These results suggest that Liq oligomers are easily formed even in the endothelial cell.

[0284] Next, we investigated the extent to which Liq is stabilized by polymerizing it from a single molecule. The structure was optimized using first-principles calculations and evaluated. aussian 09, Revision E.01, with RB3 as the basis function The evaluation was carried out under vacuum conditions using LYP / 6-311g(d,p). The energy of each polymer when it is composed of Liq alone and when it is composed of the corresponding polymer. The amount of energy stabilized by the polymerization was calculated by comparing the energy Divide the value of gy by the number of Liq to calculate the stabilized energy per Liq. The calculations and evaluations were performed on the dimer, trimer, tetramer, hexamer, and octamer of Liq. The results are shown in Figure 27.

[0285] From the graph in Figure 27, it can be seen that Liq is most stable when it becomes a hexamer. The stabilization energy per Liq in this case was about 1.54 eV. This indicates that the hexamer structure is stable and preferentially formed in Liq. It was suggested that the calculated stabilization energies of the Liq tetramer to octamer are significantly different. Since no significant difference was observed, it is considered that tetramers or higher polymers are easily formed.

[0286] From this, it can be seen that the Liq used in the electron transport layer drives the light-emitting device (passes current). It is thought that the polymers are gradually formed by passing a current through the resistor. The material that reduces the resistivity is the one that contains an organometallic complex of an alkali metal or alkaline earth metal. By forming polymers, electron mobility improves and resistance decreases.

[0287] In the light-emitting device according to one embodiment of the present invention, the recombination region reaches the electron transport layer at the initial stage of operation. However, as the device continues to operate, the AlN in the electron transport layer Clusters of organometallic complexes of potassium metals or alkaline earth metals are formed, increasing electron mobility. As a result, the recombination region is contained within the light-emitting layer. By gradually increasing the temperature, the luminance increases, and it is possible to obtain a light-emitting device with a long life and little initial deterioration. can be done.

[0288] <Reference example 1> In this reference example, the HOMO level, LUMO level and electron transfer level of the organic compounds used in each example are A method for calculating the degree of movement will now be described.

[0289] HOMO and LUMO levels are calculated based on cyclic voltammetry (CV) measurements. It is possible.

[0290] The measurement device used was an electrochemical analyzer (manufactured by BAS Co., Ltd., model number: ALS model). The solution used in the CV measurements was dehydrated dimethyl ether. Dimethylformamide (DMF) (Aldrich Co., Ltd., 99.8%, Catalog No. 227 05-6) was used as the supporting electrolyte, tetra-n-butylammonium perchlorate (nB u4NClO4) (Tokyo Chemical Industry Co., Ltd., catalog number: T0836) was added at 100 mmol / The measurement target was then dissolved in water to a concentration of 2 mmol / L. The working electrode was a platinum electrode (PT E platinum electrode) as an auxiliary electrode, and a platinum electrode (B.A.S. Co., Ltd., VC-3 P The counter electrode (5 cm) was used as the reference electrode, and the Ag / Ag+ electrode (B.A.E. The measurements were performed at room temperature (20 to 32°C). The scan speed during CV measurement was standardized to 0.1 V / sec. The oxidation potential Ea [V] and reduction potential Ec [V] of the reference electrode were measured. The intermediate potential of the reduction wave was set as Ec, and the intermediate potential of the reduction-oxidation wave was set as Ec. The potential energy of the reference electrode with respect to the vacuum level is -4.94 eV. Since it is known that the HOMO level [eV] = -4.94-Ea, the LUMO level [eV ]=-4.94-Ec. Calculate the HOMO and LUMO levels. It is possible.

[0291] Electron mobility was measured by impedance spectroscopy (Impedance Spectroscopy: It can be measured using the IS method.

[0292] The carrier mobility of EL materials is measured by the transient photocurrent method (Time-of-flight:T OF method and space-charge-limited current The method of calculating the capacitance from the IV characteristics of the SCLC (nt:SCLC method) has been known for a long time. The TOF method requires a sample with a thickness much thicker than that of an actual organic EL element. The LC method has the disadvantage that the dependence of carrier mobility on electric field strength cannot be obtained. The thickness of the organic film required for the measurement is thin, at only a few hundred nm, so even a relatively small amount of EL material is sufficient. It is possible to form a film, and the mobility can be measured with a film thickness close to that of an actual EL element. and the electric field strength dependence of carrier mobility can also be obtained.

[0293] 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.

[0294] 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.

[0295]

number

[0296] 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.

[0297]

number

[0298] 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.

[0299] In practice, first, a measurement element is fabricated using a material for which the electron mobility is to be determined. The device used is designed so that only electrons flow as carriers. The formula is shown in Figure 28. In this specification, the mobility is calculated from the frequency characteristics of the capacitance. The method (-ΔB method) will be explained.

[0300] The structure of the measurement element prepared for this measurement is shown in Figure 28. 02, a first layer 210, a second layer 211, and a third layer 212 are provided between the first layer 210 and the second layer 211. The desired material can be used as the material for the second layer 211. The electron mobility of a co-evaporated film with a weight ratio of 0.5:0.5 was measured. Specific configuration examples are summarized in the table below.

[0301] [Table 7]

[0302] The impedance measurement was performed by applying a DC voltage in the range of 5.0V to 9.0V while applying an AC voltage The measurements were performed under the conditions of a voltage of 70 mV and a frequency of 1 Hz to 3 MHz. The capacitance is calculated from the admittance (equation (1) above), which is the reciprocal of the impedance. The frequency characteristics of the calculated capacitance C at an applied voltage of 7.0 V are shown in FIG.

[0303] The frequency characteristic of capacitance C is the space charge caused by carriers injected by a small voltage signal. This occurs because the load cannot completely follow the minute AC voltage, and a phase difference occurs in the current. Here, the transit time of the carriers in the film is the time T for the injected carriers to reach the counter electrode. It is defined and expressed by the following equation (5).

[0304]

number

[0305] The negative susceptance change (-ΔB) is the capacitance change -ΔC multiplied by the angular frequency ω (-ωΔ C) The lowest frequency peak frequency f' max (=ω max / 2π) and From equation (3), the relationship between the row time T and the row time T can be derived as shown in equation (6) below.

[0306]

number

[0307] The frequency characteristics of -ΔB calculated from the above measurements (i.e., when the DC voltage is 7.0 V) are shown in Fig. 3. 0. The lowest frequency peak frequency f' obtained from Figure 30max is indicated by the arrow in the figure. did.

[0308] f' obtained from the above measurements and analysis max From this, the travel time T can be calculated (the above formula ( 6)) Using the above formula (5), calculate the electron mobility at a voltage of 7.0 V in this case. Similar measurements were performed at DC voltages ranging from 5.0V to 9.0V. Since the electron mobility at (electric field strength) can be calculated, the dependence of the mobility on the electric field strength can also be measured.

[0309] Using the above calculation method, the final electron mobility of each organic compound was calculated based on the electric field strength. The square root of the electric field strength [V / cm] read from the figure is 600 [V / cm]. 1 / 2 The electron mobility values ​​at these times are shown in Table 9.

[0310] [Table 8]

[0311] In this way, it is possible to calculate the electron mobility. , Takayuki Okachi et al. ”Japanese Journal of Applied Physics” Vol. 47, No. 12, 2008, Please see pp. 8965-8972.

[0312] <Reference example 2> In this Reference Example, the 2-phenyl-3-{4-[10-(3-pyridinyl) Regarding the synthesis method of 9-anthryl]phenyl}quinoxaline (abbreviation: PyA1PQ) The structure of PyA1PQ is shown below.

[0313] [ka]

[0314] Add 0.74 g (2.0 mL) of 3-(10-bromo-9-anthryl)pyridine to a 50 mL three-neck flask. 0.2 mmol), tri(ortho-tolyl)phosphine 0.26 g (0.85 mmol), 4-(3-phenylquinoxalin-2-yl)phenylboronic acid 0.73g (2.3mm ol), potassium carbonate aqueous solution 1.3g (9.0mmol), ethylene glycol dimethyl 40 mL of ether (DME) and 4.4 mL of water were added. The mixture was stirred under reduced pressure. The flask was degassed by this and the atmosphere inside was replaced with nitrogen.

[0315] Add 65 mg (0.29 mmol) of palladium(II) acetate to the mixture in the flask. The mixture was stirred at 80°C for 11 hours under a nitrogen stream. After stirring, water was added to the mixture in the flask, and the mixture was cooled to 30°C. The resulting extract was washed with saturated saline and dried over magnesium sulfate. This was filtered naturally, and the filtrate was concentrated to obtain an oily substance. Column chromatography (chloroform) and (toluene:ethyl acetate=5:1) twice The product was purified and recrystallized from toluene / hexane to give the desired yellow solid in an amount of 0.43 g and a yield of 36%. The synthesis scheme is shown in the following formula.

[0316] [ka]

[0317] The resulting yellow solid (0.44 g) was purified by train sublimation. The purification was carried out at 260°C for 18 hours under a pressure of 10 Pa, an argon flow rate of 5.0 mL / min, and After purification by sublimation, 0.35 g of the desired yellow solid was obtained with a recovery rate of 79%.

[0318] The yellow solid obtained in the above reaction was analyzed by nuclear magnetic resonance spectroscopy ( 1 H-NMR Analysis Results From these results, in this example, PyA1PQ represented by the above structural formula was It was found that the following was obtained.

[0319] 1 H NMR(CDCl3,300MHz):δ=7.37-7.50(m,9H), 7 .56-7.78(m,9H), 7.82-7.86(m,3H), 8.24-8.30 (m,2H), 8.75(dd,J=1.8Hz,0.9Hz,1H), 8.84(dd ,J=4.8Hz,1.8Hz,1H). [Explanation of symbols]

[0320] 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 113-1 Recombination region 114 Electron transport layer 114-1 First electron transport layer 114-2 Second electron transport layer 115 Electron injection layer 116 Charge generation layer 117 P type layer 118 Electronic Relay Layer 119 Electron injection buffer layer 120 Non-radiative recombination region 201 Anode 202 Cathode 210 First Layer 211 Second Layer 212 Third Layer 400 Substrates 401 Anode 403 EL layer 404 Cathode 405 Sealing material 406 Sealing material 407 Sealing substrate 408 Space 412 Pad 420 IC chip 501 Anode 502 Cathode 511 First Light Emitting Unit 512 Second Light Emitting Unit 513 Charge generation layer 601 Driver circuit section (source line driver circuit) 602 Pixel section 603 Drive circuit section (gate line drive 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 Insulation 616 EL layer 617 Cathode 618 Light Emitting Devices 951 Board 952 Electrode 953 Insulation Layer 954 Partition layer 955 EL layer 956 Electrode 1001 Board 1002 Undercoat 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 Bulkhead 1028 EL layer 1029 Cathode 1031 Sealing substrate 1032 Sealing material 1033 Transparent substrate 1034R Red color layer 1034G Green colored layer 1034B Blue colored layer 1035 Black Matrix 1036 Overcoat layer 1037 Third interlayer insulating film 1040 Pixel section 1041 Drive circuit section 1042 Periphery 2001 Case 2002 light source 2100 Robot 2110 Arithmetic equipment 2101 Illuminance sensor 2102 Microphone 2103 Upper Camera 2104 Speaker 2105 Display 2106 Lower Camera 2107 Obstacle Sensor 2108 Moving mechanism 3001 Lighting equipment 5000 cabinet 5001 Display section 5002 Second display unit 5003 Speaker 5004 LED Lamp 5006 Connection terminal 5007 Sensor 5008 Microphone 5012 Support part 5013 Earphones 5100 Cleaning robot 5101 Display 5102 Camera 5103 Brush 5104 Operation button 5150 Portable Information Terminal 5151 Case 5152 Display area 5153 Bend 5120 Garbage 5200 display area 5201 Display area 5202 Display area 5203 Display area 7101 Case 7103 Display section 7105 Stand 7107 Display section 7109 Operation key 7110 Remote control device 7201 Main unit 7202 Case 7203 Display section 7204 Keyboard 7205 External connection port 7206 Pointing Device 7210 Second display unit 7401 Case 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Mike 9310 Mobile Information Terminal 9311 Display Panel 9313 Hinge 9315 Case

Claims

1. An anode and a cathode, A hole injection layer, a light emitting layer, and an electron transport layer are provided between the anode and the cathode, the hole injection layer is located between the anode and the light emitting layer; the electron transport layer is located between the light emitting layer and the cathode; the hole injection layer comprises a first material and a second material; the first substance is an organic compound having a hole transporting property and a HOMO level of −5.7 eV or more and −5.4 eV or less; the second substance is a substance that exhibits electron accepting property with respect to the first substance, the electron transport layer is made of a material whose resistance value decreases when a current is passed through it; the material whose resistance value decreases when a current is passed through it contains an organometallic complex of an alkali metal or an alkaline earth metal, the electron transport layer has a first layer and a second layer; the first layer is located between the light emitting layer and the second layer; the second layer is located between the first layer and the cathode; A light emitting device, wherein the first layer contains an organometallic complex of an alkali metal or an alkaline earth metal at a different concentration from the second layer contains an organometallic complex of an alkali metal or an alkaline earth metal at a different concentration.

2. In claim 1, A light emitting device, wherein the first layer contains an organometallic complex of an alkali metal or alkaline earth metal in a concentration greater than the second layer contains an organometallic complex of an alkali metal or alkaline earth metal.

3. In claim 1 or 2, A light-emitting device, wherein the material whose resistance value decreases when a current is passed therethrough contains an organic compound having an electron transporting property, and an organometallic complex of an alkali metal or an alkaline earth metal.

4. In any one of claims 1 to 3, The organometallic complex of an alkali metal or an alkaline earth metal is a metal complex having a ligand having nitrogen and oxygen, and an alkali metal or an alkaline earth metal.

5. In any one of claims 1 to 4, The light-emitting device, wherein the organometallic complex of an alkali metal or an alkaline earth metal is a metal complex having a ligand containing an 8-hydroxyquinolinato structure and a monovalent metal ion.

6. In any one of claims 1 to 5, The light-emitting device, wherein the organometallic complex of an alkali metal or alkaline earth metal is a lithium complex having a ligand containing an 8-hydroxyquinolinato structure.

7. In any one of claims 1 to 6, A light emitting device wherein the second material is an organic compound.

8. In any one of claims 1 to 7, The light-emitting layer includes a host material and a light-emitting substance, The light-emitting material is a light-emitting device that emits blue fluorescence.

9. A light-emitting device according to any one of claims 1 to 8, a sensor, an operation button, a speaker, or a microphone; An electronic device having the

10. A light emitting apparatus comprising the light emitting device according to claim 1 and a transistor or a substrate.

11. A lighting device comprising: the light-emitting device according to claim 1 ; and a housing.

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