Light-emitting device, light-emitting apparatus, electronic appliance, and illumination apparatus

Abstract

To provide a novel light-emitting device, a light-emitting device with excellent luminous efficiency, a light-emitting device with excellent lifetime, or a light-emitting device with a low driving voltage.SOLUTION: A light-emitting device includes an anode, a cathode, and an EL layer present between the anode and the cathode. The EL layer has a light-emitting layer and an electron transport layer. The electron transport layer is present between the light-emitting layer and the cathode. The electron transport layer includes an electron transport material. The electron transport material is an organic compound having a first skeleton, a second skeleton, and a third skeleton. The first skeleton has a function of transporting electrons. The second skeleton has a function of accepting holes. The third skeleton has a single ring and a heterocyclic aromatic ring that is π electron deficient type.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] One aspect of the present invention is a light-emitting device, a light-emitting element, 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, light can be emitted from the light-emitting material.

[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, the HOM of the hole injection layer is provided between the hole transport layer in contact with the hole injection layer and the light emitting layer. A hole transporting material having a HOMO level between the O level and the HOMO level of the host material is provided. The configuration 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. Another object of the present invention is to provide a novel compound.

[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 light-emitting layer and an electron transport layer, and the electron transport layer is a layer that is connected to the light-emitting layer and the cathode. a first electrode and the second electrode, the electron transport layer having an electron transport material, the electron transport material being a first a second skeleton and a third skeleton, wherein the first skeleton is The first skeleton has a function of transporting electrons, the second skeleton has a function of accepting holes, and the third skeleton The backbone is a light-emitting device having a monocyclic and pi-electron deficient heteroaromatic ring.

[0013] Alternatively, another aspect of the present invention is a semiconductor device comprising an anode, a cathode, and a semiconductor device disposed between the anode and the cathode. The EL layer includes a light-emitting layer and an electron transport layer, and the electron transport layer is an electron The electron transport material has a first skeleton, a second skeleton, and a third skeleton. The organic compound has a function of transporting electrons, and the first skeleton has a function of transporting electrons, and the second skeleton has a function of transporting electrons. has a function of accepting holes, and the second skeleton has two or more fused aromatic hydrocarbon rings. The third skeleton is a light-emitting device having a monocyclic and π-electron-deficient heteroaromatic ring. It is a vice.

[0014] Alternatively, another aspect of the present invention is a compound according to the above-mentioned structure, wherein the second skeleton is a condensed ring of three or more rings. A light-emitting device having an aromatic hydrocarbon ring.

[0015] Alternatively, another embodiment of the present invention is a compound according to the above structure, wherein the second skeleton is a tricyclic or tetracyclic skeleton. A light emitting device that is a fused aromatic hydrocarbon ring.

[0016] Alternatively, another aspect of the present invention is a carbon atom forming a ring of the second skeleton in the above structure. The number of the light-emitting elements is 14 or more.

[0017] Alternatively, in the above-mentioned structure, the fused aromatic hydrocarbon ring is a six-membered ring. It is a light-emitting device that consists only of a semiconductor laser.

[0018] Alternatively, another aspect of the present invention is the above-mentioned structure, wherein the second skeleton is an anthracene ring. , phenanthrene ring, benzofluorene ring, tetracene ring, chrysene ring, triphenylene and a pyrene ring.

[0019] Alternatively, another embodiment of the present invention is a compound according to the above structure, wherein the second skeleton is an anthracene ring. It is a light-emitting device.

[0020] Alternatively, in the above-mentioned structure, the electron transport layer may further include a metal, a metal salt, or The light emitting device further comprises a metal oxide or an organometallic salt.

[0021] Alternatively, another aspect of the present invention is a semiconductor device comprising an anode, a cathode, and a semiconductor device disposed between the anode and the cathode. The EL layer includes a hole injection layer, a light emitting layer, and an electron transport layer, and the hole The injection layer is located between the anode and the light-emitting layer, and the electron transport layer is disposed between the light-emitting layer and The hole injection layer is located between the cathode and the hole transport material and has a hole acceptor material. The electron transport layer comprises an electron transport material and a metal, a metal salt, a metal oxide, or an organic metal salt. The hole transport material has a hole transport property and a HOMO level of −5.7 eV or more and −5.4 eV or less, and the acceptor material is the hole transport material The electron transport material is a substance that exhibits electron accepting properties to a material, and the electron transport material has a first skeleton, a second skeleton, and and a third skeleton, the first skeleton having a function of transporting electrons. The second skeleton has a function of accepting a hole, and the third skeleton is a single ring and a π-electron A light-emitting device having a heteroaromatic ring that is electron-deficient.

[0022] Alternatively, another embodiment of the present invention is a compound according to the above structure, wherein the second skeleton has two to four rings. and wherein the aromatic ring is a fused aromatic hydrocarbon ring.

[0023] Alternatively, another embodiment of the present invention is a compound according to the above structure, wherein the second skeleton is a tricyclic or tetracyclic skeleton. A light emitting device that is a fused aromatic hydrocarbon ring.

[0024] Alternatively, another aspect of the present invention is the above-mentioned structure, wherein the second skeleton is a naphthalene ring, Fluorene ring, anthracene ring, phenanthrene ring, tetracene ring, chrysene ring, triflate ring The light-emitting device includes one of a phenylene ring and a pyrene ring.

[0025] Alternatively, another aspect of the present invention is a carbon atom forming a ring of the second skeleton in the above structure. The number of the light-emitting elements is 14 or more.

[0026] Alternatively, in the above-mentioned structure, the fused aromatic hydrocarbon ring is a six-membered ring. It is a light-emitting device that consists only of a semiconductor laser.

[0027] Alternatively, another embodiment of the present invention is a compound according to the above structure, wherein the second skeleton is an anthracene ring. It is a light-emitting device.

[0028] Alternatively, in the above-described structure, the acceptor material is an organic compound. It is a light-emitting device.

[0029] Alternatively, another embodiment of the present invention is a method for manufacturing a semiconductor device comprising the steps of: or an organometallic salt thereof is a metal complex having an alkali metal or an alkaline earth metal. It is a vice.

[0030] Alternatively, another embodiment of the present invention is a method for manufacturing a semiconductor device comprising the steps of: or organometallic salts of nitrogen- and oxygen-containing ligands and alkali metals or alkaline earth metals and a metal complex having the formula:

[0031] Alternatively, another embodiment of the present invention is a method for manufacturing a semiconductor device comprising the steps of: or an organometallic salt, which is a compound having a ligand containing an 8-hydroxyquinolinato structure and a monovalent metal ion. The light-emitting device is a metal complex having

[0032] Alternatively, another embodiment of the present invention is a method for manufacturing a semiconductor device comprising the steps of: or an organometallic salt is a lithium complex having a ligand containing an 8-hydroxyquinolinato structure. It is a light-emitting device.

[0033] Alternatively, in the above-mentioned structure, another aspect of the present invention is the first and the third skeleton are bonded via the second skeleton.

[0034] Alternatively, in the above-mentioned structure, another aspect of the present invention is a method for producing a LUMO is a light-emitting device mainly distributed in the first framework.

[0035] Alternatively, another aspect of the present invention is a compound according to the above-mentioned structure, wherein the first skeleton is a condensed structure containing nitrogen. A light-emitting device that includes an aromatic ring or a triazine ring.

[0036] Alternatively, another aspect of the present invention is a method for manufacturing a semiconductor device comprising the steps of: It is a light emitting device having a light emitting element.

[0037] Alternatively, another aspect of the present invention is the above-mentioned structure, wherein the first skeleton is a quinoxaline ring. , dibenzo[h,g]quinoxaline ring, triazine ring and benzofuropyrimidine ring A light-emitting device comprising a scaffold comprising any one of the above.

[0038] Alternatively, another embodiment of the present invention is a compound according to the above structure, wherein the first skeleton is a quinoxaline ring. The light emitting device is a scaffold comprising:

[0039] Alternatively, in the above-mentioned structure, another aspect of the present invention is a method for producing a compound having a HOMO is a light-emitting device mainly distributed in the second framework.

[0040] Alternatively, another aspect of the present invention is the above-mentioned structure, wherein the third skeleton has a nitrogen atom. The present invention relates to a light-emitting device that includes a heteroaromatic ring that is a six-membered ring.

[0041] Alternatively, in the above structure, the third skeleton is a pyridine ring, The light-emitting device is one of an imidine ring, a pyrazine ring, and a triazine ring.

[0042] Alternatively, another aspect of the present invention is the above-mentioned structure, wherein the third skeleton is the second skeleton. a nitrogen atom is bonded to the second skeleton such that the nitrogen atom is at the β-position to the carbon atom bonded to It is a device.

[0043] Alternatively, another aspect of the present invention is a compound according to the above-mentioned embodiment, wherein the third skeleton is a pi-substituted ... The light-emitting device is a lysine ring, a pyrimidine ring substituted at the 5-position, or a pyrazine ring.

[0044] Alternatively, in the above-mentioned structure, the electron transport layer is in contact with the cathode. It is a light-emitting device.

[0045] 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.

[0046] Another embodiment of the present invention is a light-emitting device including any one of the above-described light-emitting devices, a sensor, and an operation button. The electronic device has a touch panel, a speaker, or a microphone.

[0047] Another embodiment of the present invention is a light-emitting device including any one of the above light-emitting devices, a transistor, and Alternatively, the light emitting device may include a substrate.

[0048] Another aspect of the present invention is a lighting device having any one of the above light-emitting devices and a housing. It is a bright device.

[0049] Alternatively, another embodiment of the present invention is a polymer having a first skeleton, a second skeleton, and a third skeleton, A compound used in an electron transport layer, the first skeleton having a function of transporting electrons, The second skeleton has a function of accepting a hole, and the third skeleton is a monocyclic and π-electron-deficient skeleton. It is a compound that has a foot-shaped heteroaromatic ring.

[0050] 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

[0051] 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. It is possible.

[0052] 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.

[0053] 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]

[0054] [Figure 1] 1(A), 1(B) and 1(C) are schematic diagrams of a light emitting device. [Diagram 2] 2(A) and 2(B) are conceptual diagrams of an active matrix type light emitting device. [Diagram 3] 3(A) and 3(B) are conceptual diagrams of an active matrix type light emitting device. [Figure 4] FIG. 4 is a conceptual diagram of an active matrix type light emitting device. [Diagram 5] 5(A) and 5(B) are diagrams showing a lighting device. [Figure 6] 6(A), 6(B1), 6(B2) and 6(C) are diagrams showing electronic devices. [Figure 7] 7(A), 7(B) and 7(C) are diagrams showing electronic devices. [Figure 8] FIG. 8 is a diagram showing a lighting device. [Figure 9] FIG. 9 is a diagram showing a lighting device. [Figure 10] FIG. 10 is a diagram showing an in-vehicle display device and a lighting device. [Figure 11] 11(A), 11(B) and 11(C) are diagrams showing electronic devices. [Figure 12] 12(A) and 12(B) are diagrams showing electronic devices. [Figure 13] FIG. 13 is a graph showing the luminance-current density characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 14] FIG. 14 is a graph showing the current efficiency-luminance characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 15] FIG. 15 is a graph showing the luminance-voltage characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 16] FIG. 16 is a graph showing the current-voltage characteristics of the light-emitting device 1 and the comparative light-emitting device 1. In FIG. [Figure 17] FIG. 17 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 18] FIG. 18 is a graph showing the emission spectra of the light-emitting device 1 and the comparative light-emitting device 1. As shown in FIG. [Figure 19] FIG. 19 is a graph showing the normalized luminance-time change characteristics of the light-emitting device 1 and the comparative light-emitting device 1. In FIG. [Figure 20] FIG. 20 is a diagram showing the structure of a measuring element. [Figure 21] FIG. 21 is a graph showing the current density-voltage characteristics of the measuring device. [Figure 22] FIG. 22 is a graph showing the frequency characteristics of the calculated capacitance C of ZADN:Liq (1:1) at a DC voltage of 7.0 V. [Figure 23] FIG. 23 is a graph showing the frequency characteristics of −ΔB of ZADN:Liq(1:1) at a DC voltage of 7.0 V. [Figure 24] FIG. 24 is a diagram showing the electric field strength dependence of electron mobility in each organic compound. [Diagram 25] Figures 25(A) and 25(B) show the 1H NMR spectrum of BfpmPPyA. [Figure 26] 26(A) and 26(B) show the 1H NMR spectrum of DBqPPyA. [Figure 27] Figures 27(A) and 27(B) show the 1H NMR spectrum of NfprPPyA. [Figure 28]FIG. 28 is a graph showing the luminance-current density characteristics of light-emitting devices 2 to 4. In FIG. [Figure 29] FIG. 29 is a graph showing the current efficiency-luminance characteristics of light-emitting devices 2 to 4. In FIG. [Diagram 30] FIG. 30 is a diagram showing the luminance-voltage characteristics of light-emitting devices 2 to 4. In FIG. [Diagram 31] FIG. 31 is a diagram showing the current-voltage characteristics of light-emitting devices 2 to 4. In FIG. [Diagram 32] FIG. 32 is a graph showing the external quantum efficiency-luminance characteristics of the light-emitting devices 2 to 4. In FIG. [Diagram 33] FIG. 33 shows the emission spectra of light-emitting devices 2 to 4. As shown in FIG. [Diagram 34] FIG. 34 is a graph showing normalized luminance-time change characteristics of light-emitting devices 2 to 4. In FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] 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.

[0056] (Embodiment 1) FIG. 1A illustrates a light-emitting device according to one embodiment of the present invention. The device has an anode 101, a cathode 102, and an EL layer 103. It has at least a light emitting layer 113 and an electron transport layer 114 .

[0057] The EL layer 103 in FIG. 1(A) includes a light-emitting layer 113 and an electron transport layer 114 as well as a positive Although a hole injection layer 111 and a hole transport layer 112 are shown, the configuration of the EL layer 103 does not depend on these. As shown in FIG. 1B, the semiconductor device may have an electron injection layer 115, or a hole injection layer 116. The transport layer 112 has a first hole transport layer 112-1 and a second hole transport layer 112-2. The electron transport layer 114 may include a first electron transport layer 114-1 and a second electron transport layer 114-2. 14-2.

[0058] In the light-emitting device according to one embodiment of the present invention, the electron transport material used in the electron transport layer 114 is , a first skeleton, a second skeleton, and a third skeleton, each of which has a different function.

[0059] The first skeleton is a skeleton having a function of transporting electrons. O is distributed mainly in the first skeleton, and the electron transport ability of this electron transport material is The first skeleton contains nitrogen to provide electron transport properties. It is preferable that the first skeleton has a condensed aromatic ring or a triazine skeleton containing a LUMO In other words, the electron-accepting ability of the first skeleton is increased, and the electron-accepting ability of the third skeleton is increased. In order to facilitate the extraction of the nitrogen atom, the first skeleton preferably contains two or more nitrogen atoms. It is particularly preferred that the two or more nitrogen atoms are located on a six-membered aromatic ring. Examples of skeletons that can be suitably used as the first skeleton include a quinoxaline ring, a dibenzo Examples of the benzo[h,g]quinoxaline ring, triazine ring, and benzofuropyrimidine ring are Among these, a skeleton containing a quinoxaline ring is preferable.

[0060] The second skeleton is a skeleton having a function of accepting holes. The second skeleton has two or more rings. In addition, in order to accept holes, the second bone is preferably a fused aromatic hydrocarbon ring. It is more preferable that the condensed aromatic hydrocarbon ring has three or more condensed aromatic hydrocarbon rings. In order to maintain sublimability and moderate solubility, it is preferable that the number of hydrogen rings is 6 or less. From the viewpoint of maintaining the energy gap, it is more preferable that the number of rings is 4 or less. In order to achieve this, the number of carbon atoms forming the condensed aromatic hydrocarbon ring must be 14 or more. In addition, in consideration of stability in the excited state, the fused aromatic hydrocarbon ring is preferably 6 It is preferable that the skeleton is composed of only membered rings. Specific examples of the condensed aromatic hydrocarbon ring include a naphthalene ring, a fluorene ring, an anthracene ring, and an aryl ring. acene ring, phenanthrene ring, benzofluorene ring, tetracene ring, chrysene ring, triphenylene ring, Among these, the aryl ring and the pyrene ring are particularly preferred. The anthracene ring is preferred because it can provide chemical stability. In this case, it is preferred that the HOMO of the electron transport material is distributed.

[0061] The third skeleton is a monocyclic heteroaromatic ring that is π-electron deficient and has the ability to inject electrons from the cathode. In order to have the above structure, it is preferable that the ring is a six-membered ring having a nitrogen atom. Specifically, pyridine ring, pyrimidine ring, pyrazine ring and triazine ring are preferred. When the carbon atom is bonded to the skeleton of the second skeleton, the third skeleton has a carbon atom bonded to the second skeleton. It is preferable that the atom at the β-position of the third skeleton is nitrogen. It is preferably a rhodamine ring, a pyridine ring substituted at the 3-position, or a pyrimidine ring substituted at the 5-position. This improves contact with the cathode and reduces the driving voltage on the high luminance side. This is because the third skeleton has such a structure. A light-emitting device having good characteristics and low driving voltage can be obtained without providing an electron injection layer between the semiconductor substrate 102 and the light-emitting element 103. can be obtained.

[0062] In addition, when the first skeleton and the third skeleton are bonded, the LUMO may be distributed to both skeletons. Preferably, these backbones are linked via a second backbone, as this increases the affinity of the backbones.

[0063] The light-emitting layer 113 includes a host material and a light-emitting material. The composition may contain other materials different from the light-emitting material and the phosphorescent material. It may be a laminate of two different layers.

[0064] 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 materials. In one embodiment of the present invention, the light-emitting layer 113 is a fluorescent layer. This is particularly suitable for a layer that emits light, particularly a layer that emits blue fluorescent light.

[0065] Examples of materials that can be used as the fluorescent substance in the light-emitting layer 113 include: 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-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA) ',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

[0066] In the case where a phosphorescent material is used as the luminescent center material in the luminescent layer 113, it is possible to use Possible materials include, for example, tris{2-[5-(2-methylphenyl)-4-(2, 6-Dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl {Ir(mpptz-dmp)3}iridium(III) (5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(I II) (abbreviation: [Ir(Mptz)3]), tris[4-(3-biphenyl)-5-iso Propyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) Title: Organic compounds with a 4H-triazole skeleton, such as [Ir(iPrptz-3b)3] Metallic iridium complexes and tris[3-methyl-1-(2-methylphenyl)-5-phenyl [Ir(Mptz) 1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2, 4-Triazolate)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]) Organometallic iridium complexes with 1H-triazole skeletons such as fac-tris[ 1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridide Ir(iPrpmi)3], tris[3-(2,6-dimethyl phenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(I II) (abbreviation: [Ir(dmpimpt-Me)3]) Organometallic iridium complexes and bis[2-(4',6'-difluorophenyl)pyridinium] To-N,C 2’ ]Iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ] Iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'- Bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) Picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6 '-Difluorophenyl)pyridinato-N,C 2’ ]Iridium(III) acetylacetone Phenylpyridine derivatives with electron-withdrawing groups such as tonato (abbreviation: FIr(acac)) Organometallic iridium complexes with conductive ligands are known. These emit blue phosphorescence. The compound shown in FIG. 1 has an emission peak at 440 nm to 520 nm.

[0067] In addition, as a material that can be used for the light-emitting layer 113, tris(4-methyl-6-phenyl) Rupyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4 -t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tB uppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidina Iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetyl Acetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(I II) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bi Bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) Name: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl Ru-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III)( Abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4, 6-Diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(a cac)]) and organometallic iridium complexes with pyrimidine skeletons such as (acetylated iridium complexes cetonato)bis(3,5-dimethyl-2-phenylpyrazinate)iridium(III)( Abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5 -isopropyl-3-methyl-2-phenylpyrazinate)iridium(III)(abbreviation: Organometallic compounds with pyrazine skeletons such as [Ir(mppr-iPr)2(acac)] Iridium complexes and tris(2-phenylpyridinato-N,C 2’ ) Iridium (III ) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ ) Ili Ir(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), Bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [ Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium (I II) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato -N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(pq)2( In addition to organometallic iridium complexes with pyridine skeletons such as tris(acac)], Cetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(a These include rare earth metal complexes such as 3(phenyl)phenyl) and 3(phenyl)phenyl). These are mainly green It is a compound that exhibits phosphorescence and has an emission peak at 500 nm to 600 nm. In addition, organometallic iridium complexes with pyrimidine skeletons are also outstanding in terms of reliability and luminescence efficiency. This is particularly preferred because

[0068] In addition, as a material that can be used for the light-emitting layer 113, (diisobutyrylmethanato)bis [4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [ Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl) [Ir(5md ppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato] (Dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dp m)]) and organometallic iridium complexes with pyrimidine skeletons such as (acetylacetonamide Nato)bis(2,3,5-triphenylpyrazinate)iridium(III) (abbreviation: [I r(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinate)(di Pivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)] ), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalina pyridinium(III) (abbreviation: [Ir(Fdpq)2(acac)]) Organometallic iridium complexes with diamine skeletons and tris(1-phenylisoquinolinato-N ,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenyl Isoquinolinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [I Organometallic iridium complexes with pyridine skeletons such as (r(piq)2(acac)] In addition, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-pol Platinum complexes such as phyrinplatinum(II) (abbreviation: PtOEP) and tris(1,3-difluorophenyl) (phenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-thenoyl)-3,3 ,3-Trifluoroacetonato](monophenanthroline)europium(III)(abbreviation These include rare earth metal complexes such as [Eu(TTA)3(Phen)]. is a compound that exhibits red phosphorescence and has an emission peak at 600 nm to 700 nm. In addition, organometallic iridium complexes with a pyrazine skeleton emit red light with good chromaticity. Obtained.

[0069] In addition to the phosphorescent compounds described above, known phosphorescent light-emitting materials may be selected and used. stomach.

[0070] 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.

[0071] [ka]

[0072] 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, an aromatic amine skeleton, a phenazine skeleton, etc. may be used as the π-electron-rich skeleton. 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.

[0073] [ka]

[0074] 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. .

[0075] 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.

[0076] As an index of the T1 level, the phosphorescence observed at low temperatures (e.g., from 77 K to 10 K) The TADF material has a fluorescence spectrum at the short wavelength end. Draw a tangent line at the wavelength of the extrapolated line and define the energy of the wavelength as the S1 level. When a tangent line is drawn at the base of the short wavelength side and the energy of the wavelength of the extrapolated line is set 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. It is more preferable that:

[0077] In addition, when a TADF material is used as the emission center 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. A level higher than 1 is preferred.

[0078] 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.

[0079] Examples of materials having hole transport properties that can be used as a host material include those having an amine skeleton or a π Organic compounds having an electron-rich heteroaromatic ring skeleton are preferred. For example, 4,4'-bis[N -(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-biphenyl S(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4 '-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluorene 4-phenyl-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP) ), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine ( Abbreviated name: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazole- 3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4' '-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PC BBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole- 3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl) -4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H -carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-Phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl] Aromatic amines such as spiro-9,9'-bifluorene-2-amine (abbreviation: PCBASF) Compounds with a benzene skeleton and 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP) , 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3, 5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'- Carbazole skeleton such as bis(9-phenyl-9H-carbazole) (abbreviation: PCCP) Compounds with 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzyl) 2,8-diphenyl-4-[4-(9- Phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBT FLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl ]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) and other thiophene bone Compounds with the structure 4,4',4''-(benzene-1,3,5-triyl)tri(diphenylphosphine) Benzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H- Fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLB i-II) and other compounds having a furan skeleton. Compounds having an isidine skeleton and compounds having a carbazole skeleton have good reliability. It is preferable because it has a high hole transport property and contributes to reducing the driving voltage. The hole transport materials given as examples of organic compounds having hole transport properties that can be used can also be used. Cut.

[0080] Examples of materials having electron transport properties that can be used as a host material include bis( 10-Hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), Bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(II) I) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), Bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), Bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ) Metal complexes and organic compounds having a π-electron deficient heteroaromatic ring skeleton are preferred. Examples of organic compounds having a toe-shaped heteroaromatic ring skeleton 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-butyl OXD-1,3,4-oxadiazol-2-yl]benzene 7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl ]-9H-Carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzene (1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzo Heterocyclization of polyazole skeleton such as imidazole (abbreviation: mDBTBIm-II) Compounds such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]ky Noxalin (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene- 4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBT BPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3- yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[ 3-(Phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm ), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6 Heterocyclic compounds with diazine skeletons such as mDBTP2Pm-II) and 3,5-bis[ 3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) , 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB) Among the above, heterocyclic compounds having a pyridine skeleton such as diazine skeleton Heterocyclic compounds having a pyridine skeleton and heterocyclic compounds having a pyridine skeleton are preferred because of their excellent reliability. In particular, heterocyclic compounds with a diazine (pyrimidine or pyrazine) skeleton have electron transport properties. This has high performance and also contributes to reducing the driving voltage.

[0081] 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. The energy is then transferred to the luminescent center, increasing the luminous efficiency of the light-emitting device. In this case, the TADF material acts as an energy donor and emits light. The central substance functions as an energy acceptor.

[0082] This is extremely effective when the luminescent center substance is a fluorescent substance. In order to obtain high luminous efficiency, the S1 level of the TADF material must be higher than the S1 level of the fluorescent material. The T1 level of the TADF material is preferably higher than the S1 level of the fluorescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent material. It is preferable that the level is higher.

[0083] 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.

[0084] 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.

[0085] When a fluorescent substance is used as the luminescence center substance, the host material is preferably an anthracene skeleton A material having an anthracene skeleton is preferably used as a host material for a fluorescent material. When used as such, it is possible to realize a light-emitting layer having good light-emitting efficiency and durability. As the anthracene skeleton material to be used, diphenylanthracene skeleton is used. In particular, substances with a 9,10-diphenylanthracene skeleton are chemically stable. In addition, when the host material has a carbazole skeleton, the hole injection / transport property is high. However, the benzocarbazole skeleton in which a benzene ring is further condensed to the carbazole is preferable. When the siloxane is included, 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 rutile by about 0.1 eV, making it easier for holes to enter. It is also preferable because it has excellent transportability and high heat resistance. Among these, 9,10-diphenylanthracene skeletons and carbazole skeletons (and It is a substance that simultaneously has a benzocarbazole skeleton or a dibenzocarbazole skeleton. From the viewpoint of the hole injection and transport properties, a benzofluorene skeleton was used instead of a carbazole skeleton. Examples of such materials include 9-fluorene and dibenzofluorene structures. phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazone PCzPA, 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9 H-Carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthraceni 7-[4-(10-phenyl)phenyl]-9H-carbazole (abbreviation: CzPA), -9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgD BCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzene Zo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10 -{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}an Trathane (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl) phenyl]anthracene (abbreviation: BH513), etc. In particular, CzPA, cgD BCzPA, 2mBnfPPA, and PCzPA are the preferred choices because they show very good properties. It is a choice.

[0086] 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.

[0087] A phosphorescent material can be used as a part of the mixed material. When a fluorescent substance is used as the luminescent center material, the luminescent substance is excited with excitation energy. It can be used as an energy donor that provides

[0088] In addition, these mixed materials may form an exciplex. The exciplex is a light-emitting material. 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.

[0089] 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

[0090] 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.

[0091] 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.

[0092] The light-emitting device of one embodiment of the present invention having the above-described structure has high reliability. In particular, the slope of the degradation curve is small, and the long-term degradation is suppressed. It can be said that

[0093] Next, other layers that can be used for the EL layer 103 will be described.

[0094] 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 high acceptor properties. However, the organic compound having a hole-transporting property and an acceptor property may be included. It is preferably constructed from a composite material.

[0095] The acceptor material is an organic compound having a hole transport property contained in the hole transport layer or the hole injection layer. It is a substance that exhibits electron accepting properties toward other substances.

[0096] Both inorganic and organic compounds can be used as the acceptor material. However, organic compounds that have electron-withdrawing groups (especially halogen groups such as fluoro groups and cyano groups) It is preferable to use the acceptor material such as a hole transporting material. A substance that exhibits electron accepting properties with respect to an organic compound having hole transport properties contained in the hole injection layer or the hole injection layer. can be appropriately selected.

[0097] Such an acceptor substance is, 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-hexaazatrif HAT-CN, 1,3,4,5,7,8-Hexafluorotetraphenylene Nonaphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1 ,3,4,5,6,8,9,10-Octafluoro-7H-pyren-2-ylidene)malonate In particular, compounds having multiple heteroatoms such as HAT-CN are Compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring are preferred because they are thermally stable. [3]Radialene derivatives containing electron-withdrawing groups (especially halogen groups such as fluoro groups and cyano groups) Conductors are preferred because they have a very high electron-accepting property. Specifically, α,α',α''-1,2, 3-Cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluoro Benzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidene Tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzene acetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetri Organic compounds such as 2,3,4,5,6-pentafluorobenzeneacetonitrile When the acceptor material is an inorganic compound, a transition metal oxide is used. In particular, oxides of metals belonging to groups 4 to 8 of the periodic table are preferred. The oxides of metals belonging to Groups 4 to 8 in the periodic table are Vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide Among these, rhenium oxide, manganese oxide, and rhenium oxide are preferred due to their high electron-accepting properties. Ribidene is preferred because it is stable in the air, has low hygroscopicity, and is easy to handle.

[0098] The organic compounds with hole transport properties used in the composite materials are hole transport materials, and their HO The MO level has a relatively deep HOMO level of -5.7 eV or more and -5.4 eV or less. It is preferable that the organic compound having hole transport properties used in the composite material has a relatively deep HOMO level. By having a position, the induction of holes is moderately suppressed, but on the other hand, the induced holes This makes it easier to inject the holes into the hole transport layer 112 .

[0099] Organic compounds with hole transport properties that can be used in composite materials include those with a carbazole skeleton, dibenzofuran skeleton, and It has either a benzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, the substituted aryl group containing a dibenzofuran ring or a dibenzothiophene ring is more preferred. Aromatic amines having a 9-membered group, aromatic monoamines having a naphthalene ring, or - an aromatic monoamine in which the fluorenyl group is attached to the nitrogen of the amine via an arylene group In addition, these substances may have an N,N-bis(4-biphenyl)amino group. The above material is preferable because it allows the production of a light-emitting device with a long life. Specifically, such substances include N-(4-biphenyl)-6,N-diphenylbenzo [b] Naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis (4-Biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine BBABnf, 4,4'-bis(6-phenylbenzo[b]naphtho[1,2 -d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1 BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6 -amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b] Naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis (4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BB ABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl ]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzo Thiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: Th BA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine ( Abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyl Nyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-( 6;1'-Binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4 ,4'-Diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (Abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl) Naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-di Phenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: B BA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-isotope BBA(βN2)B-03, 4,4'-diphenyl- 4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNα NB), 4,4'-diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenyl Nylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2 -naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4- (3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyl Biphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'- [4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TP BiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNB B1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl phenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3 -phenyl-9H-carbazol-9-yl)phenyl]tris(1,1'-biphenyl -4-yl)amine (abbreviation: YGTBi1BP-02), 4-diphenyl-4'-(2- Naphthyl)-4''-{9-(4-biphenylyl)carbazole)}triphenylamine (Abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl) -N-[4-(1-naphthyl)phenyl]-9,9'-spirobi(9H- Fluorene)-2-amine (abbreviation: PCBNBSF), N,N-bis(4-biphenylyl) )-9,9'-Spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), 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'-spirobi(9H -fluorene)-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-( Dibenzofuran-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation :FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldiphenyl Benzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN ), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine ( Abbreviated name: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl) tetrahydrofuran mBPAFLP, 4-phenyl-4'-[4-(9-phenyl (fluorofluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4 -Phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine PCBA1BP, 4,4'-diphenyl-4''-(9-phenyl-9H- Carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1- naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine PCBANB, 4,4'-di(1-naphthyl)-4''-(9-phenyl- 9H-Carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl Nyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro- 9,9'-Bifluorene-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl N-[4-(9-phenyl-9H-carbazole]-4-yl)-9,9-dimethyl -3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF) and It can be done.

[0100] In addition, the hole mobility of an organic compound with hole transport properties is proportional to the square of the electric field strength [V / cm]. If the root is 600, then 1×10 -3 cm 2 It is preferable that the value is equal to or less than / Vs.

[0101] The composition of the organic compound having the acceptor property and the hole transport property in the composite material is 1:0.0 The weight ratio is preferably 1 to 1:0.15. More preferably, the weight ratio is 1:0.0 1 to 1:0.1 (weight ratio).

[0102] The hole injection layer 111 is made of the above-mentioned composite material, and an organic compound having a hole transport property is When an organic compound with a HOMO level of -5.7 eV or more and -5.4 eV or less is used, electron transport The second skeleton of the electron transport material in the transport layer 114 is a condensed aromatic carbon having 2 to 4 rings. A hydrogen ring can be used.

[0103] In addition, the electron mobility of the electron transport layer 114 is such that the square root of the electric field strength [V / cm] is 6. 00, then 1×10 -7 cm 2 / Vs or more 5×10 -5 cm 2 / Vs or less is preferred.

[0104] Furthermore, in this case, the electron transport layer 114 contains a metal, a metal salt, a metal oxide, or an organic metal salt. Preferably, the metal, metal salt, metal oxide, or organometallic salt is an alkali metal or It is preferable that the metal complex is a metal complex having an alkaline earth metal. It is preferred to have a ligand having nitrogen and oxygen, the ligand being 8-hydroxyquinoline. Among such metal complexes, it is more preferable that they contain a monovalent metal ion. The complex of the formula (I) is preferable, and specifically, for example, 8-hydroxyquinolinato-lithium (abbreviation: L iq), 8-hydroxyquinolinato-sodium (abbreviation: Naq), etc. In particular, a lithium complex is preferred, and Liq is more preferred. If the compound contains a nolinato structure, its methyl substituents (e.g., 2-methyl and 5-methyl substituents) Body) can also be used.

[0105] As described above, the electron transport layer 114 may include a metal, a metal salt, a metal oxide, or an organometallic salt, and an electrode. When used with a hole transport material, the metal, metal salt, metal oxide, or organometallic salt transports the holes. To assist the receiving function, a condensed ring of 2 to 4 rings is used as the second skeleton of the electron transport material. Aromatic hydrocarbon rings can be preferably used. Preferred structures for the fused aromatic hydrocarbon ring As described above, examples of the fused aromatic hydrocarbon ring having 2 to 4 rings include , naphthalene ring, fluorene ring, anthracene ring, phenanthrene ring, tetracene ring, Examples of the second skeleton include a ricene ring, a triphenylene ring, and a pyrene ring. The aromatic ring is preferably a condensed aromatic ring having 3 to 4 rings, and more preferably an anthracene ring. do.

[0106] The metal, metal salt, metal oxide, or organometallic salt in the electron transport layer 114 is It is preferable that a concentration difference (including the case where the concentration is 0) exists in the thickness direction. This makes it possible to obtain a light emitting device with even better life and reliability.

[0107] The electron transport material used in the electron transport layer 114 has a HOMO level of −6.0 eV. More preferably, it is equal to or greater than this.

[0108] In a light-emitting device having such a configuration, a driving test under a constant current density condition In the case where the luminance deterioration curve obtained by the above method shows a shape having a maximum value, that is, the luminance deterioration curve shows a shape having a maximum value over time. The shape may have parts where the brightness increases over time. The light-emitting device shown in FIG. 1 shows the initial degradation, which is a rapid degradation at the beginning of operation, and the luminance increase This makes it possible to offset the initial deterioration and has a very good operating life. This type of light-emitting device is called Recombi. Nation-Site Tailoring Injection element (ReSTI element) The child shall be referred to as the

[0109] This is because the hole injection layer having the above-mentioned structure uses a hole transport material with a deep HOMO level. Since the induced holes have a large molecular weight, they can be easily injected into the hole transport layer and the light emitting layer. Therefore, in the initial stage of operation, only a small number of holes pass through the light-emitting layer and reach the electron transport layer. It is easy to achieve that state.

[0110] Here, the electron transport material and the alkali metal or alkaline earth metal element, compound, or complex In a light-emitting device having an electron transport layer containing The electron injection and transport properties of the hole injection layer are improved. Since the induction of holes is appropriately suppressed, many holes can be supplied to the electron transport layer. As a result, fewer holes can reach the electron transport layer over time, and the holes are transported to the light-emitting layer. In other words, during continuous lighting, recombination occurs more frequently in the light-emitting layer. This shift in the carrier balance makes it easier for degradation curves to occur. A light-emitting device in which the initial deterioration is suppressed, the light-emitting device having a portion in which the luminance increases with the passage of time. You can get the service.

[0111] 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. In addition, as an electron transport material, The first skeleton has a function of accepting a hole, and the second skeleton has a function of accepting a hole. Light emission according to one embodiment of the present invention using a compound having a third skeleton that is a foot-shaped heteroaromatic ring The device is a light-emitting device with very little long-term degradation and a long life. It is possible to use it as a chair.

[0112] 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 also possible to significantly reduce the time.

[0113] The hole transport layer 112 may be a single layer (FIG. 1(A)), but the first hole transport layer 112- It is preferable that the layer has a first hole transport layer 112-1 and a second hole transport layer 112-2 (FIG. 1(B)). The layer may have a plurality of hole transport layers.

[0114] The hole transport layer 112 can be formed using a hole transport material. The hole transport material used in 2 is the hole transport material that can be used as the host material described above. Alternatively, an organic compound having a hole transport property that can be used as a composite material can be used. Cut.

[0115] When the hole transport layer 112 is formed as a plurality of layers, the hole transport layers constituting the adjacent hole transport layers are The HOMO level of the hole transport layer is deeper in the material used for the hole transport layer closer to the light emitting layer 113. It is preferable that the difference is within 0.2 eV.

[0116] In addition, when the hole injection layer 111 is formed of a composite material, the hole injection layer 111 is in contact with the The HOMO level of the hole transport material used in the hole transport layer 112 is It is preferable that the depth is deeper than that of the organic compound having transport properties, and the difference is within 0.2 eV. It is nice.

[0117] The above-mentioned relationship of the HOMO levels allows holes to be smoothly injected into each layer. Therefore, it is possible to prevent an increase in driving voltage and a state in which there are insufficient holes in the light-emitting layer.

[0118] The hole transport material used in the hole transport layer 112 has a structure having a function of transporting holes. As the skeleton having the function of transporting holes, an organic compound The HOMO level of the carbazole skeleton, dibenzofuran skeleton, and dibenzothiophene skeleton is not too shallow. An olefin skeleton and an anthracene skeleton are preferred, and a dibenzofuran skeleton is particularly preferred. In addition, between adjacent layers in the hole injection layer 111 and the plurality of hole transport layers 112, It is preferable that these skeletons are common because the injection of holes becomes smooth. Between adjacent layers of the injection layer 111 and the plurality of hole transport layers 112, the same hole The use of transport materials is preferred for the same reasons.

[0119] When a plurality of hole transport layers are laminated, the first hole transport layer 112-1 is a second hole transport layer 11 The second hole transport layer 112-2 is located closer to the anode 101 than the second hole transport layer 112-2. In some cases, it also functions as an electron blocking layer.

[0120] The light-emitting device according to one embodiment of the present invention having the above-described structure has an extremely long life. It can be a vice.

[0121] (Embodiment 2) Next, examples of the detailed structure and materials of the above-mentioned light-emitting device will be described. The device has an EL layer 103 made of multiple layers between a pair of electrodes, an anode 101 and a cathode 102, The EL layer 103 includes a light-emitting layer 113 and an electron transport layer 114 from at least the anode 101 side. The EL layer 103 includes a hole injection layer, a hole transport layer, and a Various layers such as transport layer, electron injection layer, carrier block layer, exciton block layer, charge generation layer, etc. The structure can be applied.

[0122] The anode 101 is made of a metal, an alloy, or a 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.

[0123] In this embodiment, the laminated structure of the EL layer 103 is as shown in FIG. Injection layer 111, hole transport layer 112 (first hole transport layer 112-1, second hole transport layer 11 2-2), the light-emitting layer 113, the electron transport layer 114 (first electron transport layer 114-1, second electron A structure having an electron injection layer 115 in addition to a transport layer 114-2 will be described. The materials used are specifically shown below.

[0124] 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.

[0125] 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:

[0126] In addition, a charge generating layer is provided between the electron transport layer 114 and the cathode 102 instead of the electron injection layer 115. The charge generating layer may be provided with a positive potential on the layer in contact with the cathode side of the charge generating layer. The charge generating layer is a layer that can inject holes into the layer that is in contact with the anode side. At least a P-type layer is included. The P-type layer can constitute the hole injection layer 111 described above. It is preferable to form the P-type layer using the composite material mentioned above as a material that can be used. The material constituting the substrate is a film containing the above-mentioned acceptor material and a film containing a hole transport material. By applying a potential to the P-type layer, electrons are transported to the electron transport layer 114. Then, holes are injected into the cathode 102 and the light-emitting device operates.

[0127] In addition to the P-type layer, the charge generating layer may be either an electron relay layer or an electron injection buffer layer. Preferably, both are provided.

[0128] The electron relay layer contains at least a substance having an electron transport property, and the electron injection buffer layer and the P-type layer The electron relay layer has the function of preventing interactions with the The LUMO level of the electron-transporting material is the same as the LUMO level of the electron-accepting material in the P-type layer. and the LUMO level of the substance contained in the layer in contact with the charge generating layer in the electron transport layer 114. In the electron-relay layer, the electron-transporting material is preferably The specific energy level of the LUMO level is −5.0 eV or more, preferably −5.0 eV or more. The upper limit is preferably set to −3.0 eV or less. The materials are phthalocyanine-based materials or metal complexes with metal-oxygen bonds and aromatic ligands. Preferably, the body is used.

[0129] The electron injection buffer layer may include alkali metals, alkaline earth metals, rare earth metals, and their corresponding Compounds of alkali metal compounds (oxides such as lithium oxide, halides, lithium carbonate, etc.) and carbonates such as cesium carbonate), alkaline earth metal compounds (oxides, halides, carbonates), or compounds of rare earth metals (including oxides, halides, and carbonates) It is possible to use a substance having a high electron injection property such as the above.

[0130] The electron injection buffer layer is formed by containing a substance having an electron transporting property and an electron donating substance. In the case where the electron donor is an alkali metal, an alkaline earth metal, a rare earth metal, and their compounds (alkali metal compounds (oxides such as lithium oxide, halides, (including carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (oxides, halide compounds of rare earth metals (including oxides, halides, carbonates, etc.) In addition to tetrathianaphthalene (TTN), nickelocene, decamethyl An organic compound such as nickelocene can also be used. In this case, the electron transport layer 114 may be formed using the same material as that constituting the electron transport layer 114 described above. can be done.

[0131] 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, it may be formed by a wet method using a paste of a metal material.

[0132] 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.

[0133] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0134] 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.

[0135] 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 be made of a substance having a band gap larger than that of the material.

[0136] 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. The light-emitting device shown in FIG. 1C has a plurality of light-emitting units. The light-emitting device shown in FIG. 1(A) and FIG. 1(B) is a light-emitting device having one light-emitting unit. It can be said that this is

[0137] 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(A), respectively, and are described in the explanation of FIG. 1(A). The same as that described above can be applied to the first light-emitting unit 511 and the second light-emitting unit 512. The optical units 512 may be of the same construction or of different constructions.

[0138] 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.

[0139] The charge generating layer 513 is preferably formed to have the same structure as the charge generating layer described above. Composite materials of compounds and metal oxides have excellent carrier injection and carrier transport properties, It is possible to realize low voltage and low current driving. When the charge generating layer 513 is in contact with the charge generating layer 513, the charge generating layer 513 serves as a hole injection layer of the light emitting unit. Since the light-emitting unit can also serve as a hole-injection layer, the light-emitting unit does not need to be provided with a hole-injection layer.

[0140] In addition, when an electron injection buffer layer is provided in the charge generating layer 513, the electron injection buffer layer To play the role of an electron injection layer in the light-emitting unit on the anode side, It is not always necessary to form an electron injection layer.

[0141] 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.

[0142] 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.

[0143] 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 polymeric materials.

[0144] (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.

[0145] 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. 2. FIG. 2(A) shows the light-emitting device. FIG. 2(B) is a cross-sectional view taken along lines AB and CD in FIG. 2(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.

[0146] 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 include 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.

[0147] 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.

[0148] 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.

[0149] 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.

[0150] 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.

[0151] 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 allows the current in the MOSFET's low-voltage state to be reduced.

[0152] 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.

[0153] Here, an oxide semiconductor that can be used in one embodiment of the present invention will be described. .

[0154] 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.

[0155] 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 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.

[0156] 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 distortion can be tolerated by changing the frequency band.

[0157] 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.

[0158] 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.

[0159] 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.

[0160] 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.

[0161] 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.

[0162] 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.

[0163] In addition to the oxide semiconductors mentioned above, Cloud-Aligned Computing (CAC) osite)-OS may also be used.

[0164] 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 active layer, the conductive function is to allow the electrons (or holes) that serve as carriers to flow. The insulating function is to prevent the flow of electrons, which act as carriers. The function of switching (O On / Off function) can be added to CAC-OS. By separating their functions, the functions of both can be maximized.

[0165] 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 and insulating regions may be unevenly distributed in the material. may be observed as a cloud-like formation with the edges blurred.

[0166] 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.

[0167] 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.

[0168] That is, CAC-OS is a matrix composite. or metal matrix composite It can also be called.

[0169] 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.

[0170] 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.

[0171] 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.

[0172] 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. .

[0173] 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.

[0174] An insulator 614 is formed to cover the end of the anode 613. It can be formed by using a photosensitive acrylic.

[0175] 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.

[0176] 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.

[0177] 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). .

[0178] 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).

[0179] 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.

[0180] 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.

[0181] 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.

[0182] Although not shown in FIG. 2B, a protective film may be provided on the cathode. The protective film is an organic resin film. In addition, a protective film may be formed so as to cover the exposed portion of the sealant 605. A protective film may be formed on the front and side surfaces of the pair of substrates, the sealing layer, the insulating layer, etc. A border layer, etc. may be provided over the exposed sides.

[0183] 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.

[0184] 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.

[0185] 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.

[0186] 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. .

[0187] 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.

[0188] 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.

[0189] In FIG. 3(A) and FIG. 3(B), a light-emitting device that emits white light is formed, and a colored layer (color An example of a full-color light-emitting device is shown in FIG. 3(A). The substrate 1001 includes a base insulating film 1002, a gate insulating film 1003, a gate electrode 1006, 1007, 1008, first interlayer insulating film 1020, second interlayer insulating film 1021, peripheral portion 1 042, pixel section 1040, driving circuit section 1041, anode 1024W of the light-emitting device, 102 4R, 1024G, 1024B, partition 1025, EL layer 1028, cathode 1 of light emitting device 029, a sealing substrate 1031, a sealant 1032, etc. are shown.

[0190] In addition, in FIG. 3(A), the colored layers (red colored layer 1034R, green colored layer 1034G, blue The colored layer 1034B is provided on a transparent substrate 1033. A transparent substrate 1 having a colored layer and a black matrix may be further 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-emitting layer is a layer where light does not pass through the colored layers and goes out to the outside, and the light passes through the colored layers of each color and goes out to the outside. 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.

[0191] In FIG. 3B, 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. Good too.

[0192] 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. 4. 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.

[0193] 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.

[0194] In the top emission structure shown in Fig. 4, 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 by the overcoat layer 1036. Note that the sealing substrate 1031 is formed using a substrate having a light-transmitting property. In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, the present invention is not limited to this. Alternatively, full color display may be performed using four colors, red, yellow, green, and blue, or three colors, red, green, and blue.

[0195] 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 serves as a light-emitting region.

[0196] 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.

[0197] 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.

[0198] 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

[0199] 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.

[0200] 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.

[0201] 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.

[0202] 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.

[0203] (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 light source as a light source will be described with reference to Figs. 5(A) and 5(B). Fig. 5(B) shows a lighting example. FIG. 5(A) is a top view of the device, and FIG. 5(A) is a cross-sectional view taken along line ef in FIG. 5(B).

[0204] 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.

[0205] A pad 412 for supplying a voltage to the cathode 404 is formed on the substrate 400 .

[0206] 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.

[0207] 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.

[0208] 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.

[0209] 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. 5(B) ) (not shown) can also be mixed with a desiccant, which can absorb moisture. This leads to improved reliability.

[0210] 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 carrying the same may also be provided.

[0211] 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.

[0212] (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.

[0213] 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.

[0214] FIG. 6A 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.

[0215] 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.

[0216] 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.

[0217] FIG. 6(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. 6(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.

[0218] FIG. 6C 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.

[0219] In the mobile terminal shown in FIG. 6C, 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.

[0220] 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.

[0221] 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.

[0222] 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.

[0223] 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.

[0224] 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.

[0225] 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.

[0226] 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.

[0227] 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.

[0228] FIG. 7(A) is a schematic diagram showing an example of a cleaning robot.

[0229] 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.

[0230] 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.

[0231] 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.

[0232] 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.

[0233] 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.

[0234] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0235] The robot 2100 shown in FIG. 7B includes a computing device 2110, an illuminance sensor 2101, a microphone 2102, upper camera 2103, speaker 2104, display 2105, The vehicle is equipped with an internal camera 2106, an obstacle sensor 2107, and a movement mechanism 2108.

[0236] 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.

[0237] 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.

[0238] 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.

[0239] FIG. 7C is a diagram showing an example of a goggle-type display. For example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, Connection terminal 5006, sensor 5007 (force, displacement, position, speed, acceleration, angular velocity, rotation speed, Distance, light, liquid, magnetism, temperature, chemicals, sound, time, hardness, electric field, current, voltage, power, radiation (including functions to measure radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), The device has a microphone 5008, a display unit 5002, a support unit 5012, earphones 5013, etc.

[0240] 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. .

[0241] FIG. 8 shows a configuration of the light-emitting device according to the first and second embodiments, which is an electric lighting device. This is an example of a desk lamp. The desk lamp shown in FIG. 8 is made up of a housing 2001 and a light source 2002. The lighting device described in the third embodiment may be used as the light source 2002.

[0242] FIG. 9 shows a configuration of the light-emitting device according to the first and second embodiments, which is installed in an indoor lighting device 30. The light emitting devices described in the first and second embodiments are used as a signal processing device. Since the light emitting device is highly reliable, it can be used as a highly reliable lighting device. The light emitting devices described in the first and second embodiments can be made large in area. The device can be used as a lighting device for a wide area. The light emitting device is thin and can be used as a thin lighting device. do.

[0243] 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.

[0244] 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.

[0245] 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, blind spots can be eliminated. By projecting images to complement the invisible parts, it is possible to improve safety. This allows safety checks to be performed more naturally and without any awkwardness.

[0246] The display area 5203 also displays navigation information, speedometer, tachometer, odometer, fuel gauge, gear By displaying the status, air conditioning settings, etc., various information can be provided. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in display areas 5200 to 5202. The area 5200 to the display area 5203 can also be used as a lighting device.

[0247] 11(A) to (C) show a foldable portable information terminal 9310. FIG. 11(A) shows a portable information terminal 9310 in an unfolded state. FIG. 11(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. 11C 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.

[0248] 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.

[0249] 12(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. 12(A) shows the portable information terminal 5150 in an unfolded state. FIG. 5B) shows the portable information terminal 5150 in a folded state. The portable information terminal 5150 is large. Although it has a large display area 5152, it can be folded up to be compact and highly portable.

[0250] 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.

[0251] 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. EXAMPLES

[0252] In this example, a light-emitting device 1 which is a light-emitting device according to an embodiment of the present invention and a light-emitting device for comparison are The fabrication method and characteristics of comparative light-emitting device 1 are shown below. The first skeleton has a transport property, the second skeleton accepts holes, and a monocyclic and π-electron-deficient complex structure. As an electron transport material having a third skeleton which is a simple aromatic ring, 2-phenyl-3-{4-[ 10-(3-pyridyl)-9-anthryl]phenyl}quinoxaline (abbreviation: PyA1P Q) in the electron transport layer. 2-{4-[9,10-di(naphthalene-2-yl)-2-anthryl]furan instead of PQ A luminescent device using {1-phenyl-1H-benzimidazole}- The structural formulas of the materials used in this example are shown below.

[0253] [ka]

[0254] <How to make 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 70 nm and the electrode area was 4 mm 2 (2mm x 2mm).

[0255] 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.

[0256] 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.

[0257] Next, the substrate on which the anode 101 is formed is placed in a vacuum so that the surface on which the anode 101 is formed faces downward. The substrate was fixed to a substrate holder installed in the vacuum evaporation apparatus, and evaporation was performed on the anode 101 using resistance heating. The N,N-bis(4-biphenyl)-6-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 ALD-MP001Q. It is an organic compound having the formula:

[0258] 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.

[0259] Next, 9-(1-naphthyl)-10-[4-(2-naphthyl)-1-propanol represented by the above structural formula (iii) αN-βNPAnth) and the above structural formula (iv) Represented by 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N -phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3, 10PCA2Nbf(IV)-02) in a weight ratio of 1:0.015 (=αN-βNPAn th: 3,10PCA2Nbf(IV)-02) to form a 25 nm light-emitting layer. 113 was formed.

[0260] Then, on the light-emitting layer 113, 2-phenyl-3-{4-[1 0-(3-pyridyl)-9-anthryl]phenyl}quinoxaline (abbreviation: PyA1PQ ) and 8-hydroxyquinolinato-lithium (abbreviation: Liq ) was co-deposited at a weight ratio of 1:2 (=PyAlPQ:Liq) to a thickness of 12.5 nm. The PyAlPQ:LiQ layer was co-deposited at a weight ratio of 2:1 (PyAlPQ:LiQ) to a thickness of 12.5 nm. A transfer layer 114 was formed.

[0261] After forming the electron transport layer 114, aluminum is evaporated to a thickness of 200 nm. In this way, the cathode 102 was formed, and the light-emitting device 1 of this example was fabricated.

[0262] <How to make comparative light-emitting device 1> The comparative light-emitting device 1 is a light-emitting device in which PyA1PQ in the light-emitting device 1 is replaced with a compound represented by the above structural formula (vii). 2-{4-[9,10-di(naphthalene-2-yl)-2-anthryl]phenyl} The other components were changed to {1H-phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN). It was fabricated in the same manner as optical device 1.

[0263] The device structures of Light-Emitting Device 1 and Comparative Light-Emitting Device 1 are summarized in the table below.

[0264] [Table 1]

[0265] 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 UV treatment at the end of the test, and heat treatment at 80℃ for 1 hour, the light-emitting device 1 and the comparative light-emitting device The initial characteristics and reliability of Device 1 were measured. The measurements were carried out at room temperature.

[0266] The luminance vs. current density characteristics of the light-emitting device 1 and the comparative light-emitting device 1 are shown in FIG. The luminance characteristics are shown in Fig. 14, the luminance-voltage characteristics in Fig. 15, the current-voltage characteristics in Fig. 16, and the external quantum efficiency The efficiency-luminance characteristics are shown in FIG. 17, and the emission spectrum is shown in FIG. Comparative light-emitting device 1: 1000cd / m 2 The main characteristics of the area are shown in Table 2.

[0267] [Table 2]

[0268] 13 to 18 and Table 2, the light-emitting device 1 according to one embodiment of the present invention has good initial characteristics. It was found that the device was a blue light-emitting device having excellent optical properties.

[0269] 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. 19, a light-emitting device 1 according to one embodiment of the present invention is The long-term slope of the luminescence intensity after the initial change has subsided is smaller than that of the comparative light-emitting device 1. It was found to be a good light-emitting device with a long lifespan with little long-term degradation.

[0270] In addition, in the light-emitting device 1 and the comparative light-emitting device 1, the hole injection layer has a hole transport property, and H BBABnf with OMO levels between -5.7 eV and -5.4 eV, and The electron transport layer contains metal, metal salt, and gold. Liq is an organometallic oxide or an organometallic salt.

[0271] As a result, the luminance of the light-emitting device 1 and the comparative light-emitting device 1 increased after driving, and the initial luminance This shows that the brightness is higher than that of the initial brightness and then gradually decreases. As a standard, the time until deterioration occurs by 2 to 5% (initial operating life) can be significantly extended.

[0272] As described above, the light-emitting device 1 exhibits a very long lifespan due to its small long-term deterioration. It was found to be a light-emitting device. EXAMPLES

[0273] <Synthesis Example 1> In this synthesis example, a compound that can be used as an electron transport material in a light-emitting device according to one embodiment of the present invention is The compound 4-{4-[10-(3-pyridyl)-9-anthryl]phenyl}[1] This article explains the synthesis method of benzofuro[3,2-d]pyrimidine (abbreviation: BfpmPPyA). The structure of BfpmPPyA is shown below.

[0274] [ka]

[0275] <Step 1: 4-(4-chlorophenyl)[1]benzofuro[3,2-d]pyrimidine Synthesis of > 4-Chloro[1]benzofuro[3,2-d]pyrimidine 2.0 g (9.7 mmol), 4 -Chlorophenylboronic acid 1.8 g (12 mmol), tri(ortho-tolyl)phosphine 0.30 g (0.97 mmol) of ethanol and 2.7 g (19 mmol) of potassium carbonate were added to a three-port flask. To this mixture, 100 mL of toluene, 20 mL of ethanol, and 10 mL of water were added. The mixture was then stirred under reduced pressure to degas it. Then, 0.044 g of palladium(II) acetate was added to the mixture. (0.19 mmol) was added and stirred at 80°C for 6 hours. ) 0.027g (0.097mmol), tri(ortho-tolyl)phosphine 0.20g (0.44 mmol) was added, and the mixture was stirred at 80° C. for 2 hours.

[0276] After stirring, water was added to the mixture, the aqueous layer was separated, and the organic layer was filtered. The resulting extract was combined with the filtrate and washed with water. The organic layer was then extracted with toluene. The mixture was separated by gravity filtration, and the filtrate was concentrated. The solid was purified by silica gel column chromatography (eluent: toluene:ethyl acetate=9 The product was purified by the method described in step 1) to obtain 2.5 g of a pale yellow solid in 92% yield. The reaction scheme of 1 is shown below.

[0277] [ka]

[0278] <Step 2: 4-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxabo Synthesis of loran-2-yl)phenyl][1]benzofuro[3,2-d]pyrimidine> 4-(4-chlorophenyl)[1]benzofuro[3,2-d]pyrimidine 2.5 g (8. 9 mmol), bis-pinacolatodiboron 2.7 g (11 mmol), potassium acetate 2. 6 g (27 mmol) of ethylene glycol and 45 mL of xylene were placed in a three-neck flask and purged with nitrogen. Compound with [1,1'-bis(diphenylphosphino)ferrocene]palladium(II) dichloride Pd(dppf)Cl2 · CH2Cl2) 0.3 6 g (0.44 mmol) was added, and the mixture was stirred at 120° C. for 17 hours.

[0279] After stirring, toluene and water were added to the mixture, and the solution was filtered. The organic layer of the filtrate was taken out. The aqueous layer was extracted with toluene. The resulting extract and the organic layer were combined and washed with water. The layer was dried over magnesium sulfate, and the mixture was separated by gravity filtration, and the filtrate was concentrated. The resulting solid was dissolved in toluene and filtered through Celite, Florisil, and alumina. The filtrate was concentrated and the resulting solid was filtered off with toluene and ethyl acetate (solvent: toluene:ethyl acetate = 4:1). Purification by gel column chromatography (developing solvent toluene:ethyl acetate=3:1) The target yellow solid was obtained in an amount of 2.6 g and a yield of 79%. is shown below.

[0280] [ka]

[0281] <Step 3: 4-{4-[10-(3-pyridyl)-9-anthryl]phenyl}[1 Synthesis of benzofuro[3,2-d]pyrimidine (abbreviation: BfpmPPyA) In a 200 mL three-neck flask, add 1.6 g of 3-(10-bromo-9-anthryl)pyridine ( 4.8mmol) and 4-[4-(4,4,5,5-tetramethyl-[1,3,2]diox Saborolan-2-yl)-phenyl]-[1]benzofuro[3,2-d]pyrimidine2. 0g (5.3mmol), tri(o-tolyl)phosphine 0.15g (0.48mmol 1.3 g (9.6 mmol) of potassium carbonate was added and the atmosphere in the flask was replaced with nitrogen. Add 50 mL of toluene, 10 mL of ethanol, and 5 mL of water to the mixture and stir under reduced pressure. The mixture was degassed by 22 mg (0.096 mmol) of palladium(II) acetate. The mixture was stirred at 80°C for 11 hours under a nitrogen stream. After a certain time had elapsed, water was added to the mixture. The precipitated solid was collected by suction filtration and washed with water and methanol. By silica gel column chromatography (eluent: toluene: ethyl acetate = 9:1), The solid was purified by filtration and then recrystallized from toluene to obtain 1.4 g (2.8 mm ol) was obtained in a yield of 57%. The synthesis scheme for step 3 is shown below.

[0282] [ka]

[0283] The obtained solid (1.3 g) was purified by train sublimation. The conditions were a pressure of 3.0 Pa, an argon flow rate of 5 mL / min, and a temperature of 275°C. 1.2 g of BfpmPPyA powder was obtained with a recovery rate of 91%.

[0284] Nuclear magnetic resonance spectroscopy of the obtained compound ( 1 The results of H-NMR are shown in Figure 25(A)(B) ) and the numerical data is shown below. 1 H NMR (CDCl3, 300 MHz): δ = 7. 36-7.44(m,4H), 7.54-7.69(m,4H), 7.73-7.89( m,7H), 8.37(d,J=7.7Hz,1H), 8.77(dd,J=2.2Hz ,0.7Hz,1H), 8.83-8.91(m,3H), 9.36(s,1H). It was found that BfpmPPyA was obtained in this synthesis example. EXAMPLES

[0285] <Synthesis Example 2> In this synthesis example, a compound that can be used as an electron transport material in a light-emitting device according to one embodiment of the present invention is The compound 2-{4-[10-(3-pyridyl)-9-anthryl]phenyl}dibene This article explains the synthesis method of quinoxaline (DBqPPyA). The structure of qPPyA is shown below.

[0286] [ka]

[0287] <Step 1: 2-{4-[10-(3-pyridyl)-9-anthryl]phenyl}dibenzyl Synthesis of benzo[f,h]quinoxaline (abbreviation: DBqPPyA) In a 150 mL three-neck flask, add 1.1 g of 3-(10-bromo-9-anthryl)pyridine ( 3.2mmol) and 2-(4,4,5,5-tetramethyl-1,3,2-dioxaborola 1.5g (3.5mmol)dibenzo[f,h]quinoxaline, tri(o 96 mg (0.32 mmol) of 6-phenyl-2-thiazolinone phosphine, 0.87 g (6 30 mL of toluene and ethanol were added to the mixture, and the atmosphere in the flask was replaced with nitrogen. 6.0 mL of alcohol and 3.0 mL of water were added, and the mixture was degassed by stirring under reduced pressure. Palladium(II) acetate (14 mg, 0.063 mmol) was added to the mixture, and the mixture was stirred for 8 h under a nitrogen stream. The mixture was stirred at 0°C for 21 hours. After the specified time had elapsed, water was added to the mixture, and the solid was filtered off with suction. Toluene was added to the obtained solid, and the mixture was irradiated with ultrasonic waves, and then the solid was collected.

[0288] The solid obtained was purified by silica gel column chromatography (eluent: chloroform). After purification, the product was recrystallized from a mixed solvent of toluene and ethanol, and the target solid was obtained in 0. The synthesis scheme for step 1 is shown below.

[0289] [ka]

[0290] The obtained solid (0.96 g) was purified by train sublimation. The conditions were a pressure of 2.9 Pa, an argon flow rate of 5 mL / min, and a temperature of 305°C. 0.80 g of DBqPPyA powder was obtained with a recovery rate of 82%.

[0291] Nuclear magnetic resonance spectroscopy of the obtained compound ( 1 The results of H-NMR are shown in Figure 26(A)(B) ) and the numerical data is shown below. 1 H NMR (CDCl3, 300 MHz): δ = 7. 38-7.45(m,4H), 7.57-7.69(m,3H), 7.72-7.91( m,9H), 8.63(d,J=8.1Hz,2H), 8.70(d,J=7.7Hz, 2H), 8.77-8.80(m,1H), 8.85(dd,J=1.5Hz,4.8H z,1H), 9.28-9.32(m,1H), 9.49-9.54(m,1H), 9. 57(s,1H). This shows that DBqPPyA was obtained in this synthesis example. I did. EXAMPLES

[0292] <Synthesis Example 3> In this synthesis example, a compound that can be used as an electron transport material in a light-emitting device according to one embodiment of the present invention is The compound (9-{4-[10-(3-pyridyl)-9-anthryl]phenyl}naphthalene NfprPPyA The synthesis method is described below. The structure of NfprPPyA is shown below.

[0293] [ka]

[0294] <Step 1: 9-[4-(4,4,5,5-tetramethyl-[1,3,2]dioxabo loran-2-yl)-phenyl]naphtho[1',2':4,5]furo[2,3-b]pyra Synthesis of gin> 9-(4-Chlorophenyl)-naphtho[1',2':4,5]furo[2,3-b]pyrazine 3.2g (9.7mmol), bis-pinacolatodiboron 3.0g (12mmol), 2.9 g (29 mmol) of potassium acetate and 50 mL of xylene were placed in a three-neck flask and the pressure was reduced. The mixture was stirred at room temperature and degassed. sen]palladium(II) dichloromethane adduct (abbreviation: Pd(dppf)Cl2)0. 40 g (0.49 mmol) was added, and the mixture was stirred at 120° C. for 19 hours.

[0295] After a certain time had elapsed, toluene was added to the mixture, and the solution was separated by filtration using Celite, Florisil, The mixture was filtered through alumina (solvent toluene:ethyl acetate=1:1), and the filtrate was concentrated. The obtained solid was purified by silica gel column chromatography (eluent: toluene:ethyl acetate The solid was purified by a hexane extraction method (hexane = 3:1) to obtain a yellow solid. The solid was added with hexane and irradiated with ultrasound. The solid was collected by suction filtration to obtain the desired yellow solid (yield: 3.7 g, yield: The synthesis scheme for step 1 is shown below.

[0296] [ka]

[0297] <Step 2: (9-{4-[10-(3-pyridyl)-9-anthryl]phenyl}na NfprPPyA (futo[1',2':4,5]furo[2,3-b]pyrazine) (abbreviation: NfprPPyA) Synthesis of > In a 200 mL three-neck flask, add 1.4 g of 3-(10-bromo-9-anthryl)pyridine ( 4.1mmol) and 3-[4-(4,4,5,5-tetramethyl-[1,3,2]diox Saborolan-2-yl)-phenyl]naphtho[1',2':4,5]furo[2,3-b] Pyrazine 1.9 g (4.5 mmol), tri(o-tolyl)phosphine 0.13 g (0. 41 mmol), 1.1 g (8.3 mmol) of potassium carbonate were added, and the flask was replaced with nitrogen. To this mixture, 40 mL of toluene, 8 mL of ethanol, and 4 mL of water were added and stirred under reduced pressure. The mixture was degassed by stirring. 19 mg (0.083 g) of palladium (II) acetate was added to the mixture. The mixture was stirred at 80°C for 10 hours under a nitrogen stream. Water was added to the mixture, and the precipitated solid was collected by suction filtration. The obtained solid was dissolved in water, methanol, and The solid obtained was purified by silica gel column chromatography (eluent: toluene). The product was purified with a toluene / ethyl acetate ratio of 9:1 and then recrystallized from toluene to obtain the desired compound. The solid was obtained in an amount of 1.3 g (2.4 mmol) with a yield of 58%. The synthesis scheme for step 2 is as follows: Shown below.

[0298] [ka]

[0299] The obtained solid (1.3 g) was purified by train sublimation. The conditions were pressure 3.3 Pa, argon flow rate 15 mL / min, and temperature 320°C. After sublimation purification, 0.94 g of NfprPPyA powder was obtained with a recovery rate of 73%.

[0300] Nuclear magnetic resonance spectroscopy of the obtained compound ( 1 The results of H-NMR are shown in Figure 27(A)(B) ) and the numerical data are shown below. 1 H NMR (CDCl3, 300 MHz): δ = 7. 36-7.45(m,4H), 7.56-7.74(m,6H), 7.78-7.91( m,5H), 8.08(d,J=8.1Hz,1H), 8.13(d,J=8.8Hz, 1H), 8.45(d,J=8.4Hz,2H), 8.76-8.78(m,1H), 8 .85(dd,J=4.4Hz,1.5Hz,1H), 9.21(d,J=8.4Hz, 1H), 9.42 (s, 1H). This resulted in the synthesis of NfprPPyA. It was found that this was the case. EXAMPLES

[0301] In this example, light-emitting devices 2 to 4, which are light-emitting devices according to one embodiment of the present invention, will be described. The fabrication method and characteristics of the light-emitting devices 2 to 4 are shown. The first skeleton has a transport property, the second skeleton accepts holes, and a monocyclic and π-electron-deficient complex structure. The electron transport material has a third skeleton which is a halogen-containing aromatic ring. Specifically, the light-emitting device 2 is a 4-{4-[10-(3-pyridyl)-9-anthryl ]phenyl}[1]benzofuro[3,2-d]pyrimidine (abbreviation: BfpmPPyA), The light-emitting device 3 is a 2-{4-[10-(3-pyridyl)-9-anthryl]phenyl}diphenyl The light-emitting device 4 is (9-{ 4-[10-(3-pyridyl)-9-anthryl]phenyl}naphtho[1',2':4, 5]furo[2,3-b]pyrazine) (abbreviation: NfprPPyA). The structural formulas of the materials used are shown below.

[0302] [ka]

[0303] <How to make light-emitting device 2> 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 70 nm and the electrode area was 4 mm 2 (2mm x 2mm).

[0304] 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.

[0305] 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.

[0306] Next, the substrate on which the anode 101 is formed is placed in a vacuum so that the surface on which the anode 101 is formed faces downward. The substrate was fixed to a substrate holder installed in the vacuum evaporation apparatus, and evaporation was performed on the anode 101 using resistance heating. The N,N-bis(4-biphenyl)-6-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 ALD-MP001Q. It is an organic compound having the formula:

[0307] 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.

[0308] Next, 9-(1-naphthyl)-10-[4-(2-naphthyl)-1-propanol represented by the above structural formula (iii) αN-βNPAnth) and the above structural formula (iv) Represented by 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N -phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3, 10PCA2Nbf(IV)-02) in a weight ratio of 1:0.015 (=αN-βNPAn th: 3,10PCA2Nbf(IV)-02) to form a 25 nm light-emitting layer. 113 was formed.

[0309] Then, on the light-emitting layer 113, 4-{4-[10-(3 -pyridyl)-9-anthryl]phenyl}[1]benzofuro[3,2-d]pyrimidine (abbreviation: BfpmPPyA) and 8-hydroxyquinolinate represented by the above structural formula (vi) -Lithium (abbreviation: Liq) in a weight ratio of 1:2 (=BfpmPPyA:Liq) As shown in FIG.

[0310] After forming the electron transport layer 114, aluminum is evaporated to a thickness of 200 nm. In this way, the cathode 102 was formed, and the light-emitting device 2 of this example was fabricated.

[0311] <How to make light-emitting device 3> The light-emitting device 3 is a light-emitting device 2 having the same structure as that of the light-emitting device 2 except that BfpmPPyA is replaced with a compound represented by the above structural formula (ix). 2-{4-[10-(3-pyridyl)-9-anthryl]phenyl}dibenzo[ f,h] The same as for light-emitting device 2, except that quinoxaline (abbreviation: DBqPPyA) was used. It was made.

[0312] <How to make light-emitting device 4> The light-emitting device 4 is the same as the light-emitting device 2 except that the electron transport layer 114 is a compound represented by the above structural formula (x). (9-{4-[10-(3-pyridyl)-9-anthryl]phenyl}naphtho[1 ',2':4,5]furo[2,3-b]pyrazine) (abbreviation: NfprPPyA) and Liq and Liq were co-deposited at a weight ratio of 1:2 (=NfprPPyA:Liq) to a thickness of 12.5 nm. Then, 12.5 nm of NfprPPyA was co-evaporated at a weight ratio of 2:1 (=NfprPPyA:Liq). The other steps were the same as those for the light-emitting device 2.

[0313] The device structures of Light-Emitting Device 2 to Light-Emitting Device 4 are summarized in the table below.

[0314] [Table 3]

[0315] 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 that, light-emitting device 2 was subjected to UV treatment at the time of stopping and heat treatment at 80°C for 1 hour. The initial characteristics and reliability of the device were measured at room temperature.

[0316] FIG. 28 shows the luminance vs. current density characteristics of the light-emitting devices 2 to 4. The luminance-voltage characteristics are shown in Fig. 29, the current-voltage characteristics in Fig. 30, and the external quantum efficiency- The luminance characteristics are shown in FIG. 32, and the emission spectrum is shown in FIG. 1000cd / m on Vice 4 2 The main characteristics of the area are shown in Table 4.

[0317] [Table 4]

[0318] 28 to 33 and Table 4, light-emitting device 2 to light-emitting device 3 which are embodiments of the present invention are shown. 4 was found to be a blue-emitting device with good initial characteristics.

[0319] 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. 34, a light-emitting device 2 according to one embodiment of the present invention is shown. The light emitting device 4 has a small long-term gradient after the initial change has subsided, and is therefore less susceptible to long-term deterioration. It was found that this was a light-emitting device with a long life.

[0320] In addition, the light-emitting devices 2 to 4 each have a hole-injection layer that has a hole-transporting property and a HOMO BBABnf, whose level is between -5.7 eV and -5.4 eV, and BBABnf, which accepts electrons The electron transport layer contains metals, metal salts, and metal oxides. The compound has Liq, which is an organic metal salt.

[0321] As a result, the luminance of the light emitting device 3 increases after it is driven and then gradually decreases. This allows the time it takes for the initial brightness to deteriorate by 2 to 5% (initial operating life) can be significantly increased.

[0322] (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.

[0323] HOMO and LUMO levels are calculated based on cyclic voltammetry (CV) measurements. It is possible.

[0324] 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.

[0325] Electron mobility was measured by impedance spectroscopy (Impedance Spectroscopy: It can be measured using the IS method.

[0326] 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.

[0327] 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.

[0328] 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.

[0329]

number

[0330] 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.

[0331]

number

[0332] 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.

[0333] In practice, first, a measuring device for the material whose electron mobility is to be determined is fabricated. The design is such that only electrons flow as carriers. In this specification, the capacitance is determined based on the frequency characteristics. The method for calculating the mobility from the measured value (-ΔB method) is explained below. show.

[0334] The structure of the measurement element prepared for this measurement is shown in Figure 20. 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. An example of measuring the electron mobility of a co-deposited film having a weight ratio of 1:1 will be described. Typical configuration examples are summarized in the table below.

[0335] [Table 5]

[0336] The current density-voltage of the measurement element in which the co-evaporation film of ZADN and Liq was fabricated as the second layer 211 was The pressure characteristics are shown in FIG.

[0337] 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.

[0338] 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).

[0339]

number

[0340] 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.

[0341]

number

[0342] The frequency characteristics of -ΔB calculated from the above measurements (i.e., when the DC voltage is 7.0 V) are shown in Fig. 2. The lowest frequency peak frequency f' obtained from Figure 23 is shown in Fig. 3. max is indicated by the arrow in the figure. did.

[0343] 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.

[0344] 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 6.

[0345] [Table 6]

[0346] 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.

[0347] (Reference example 2) <Synthesis Example 4> 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.

[0348] [ka]

[0349] 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.

[0350] 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.

[0351] [ka]

[0352] 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%.

[0353] 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.

[0354] 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]

[0355] 101 Anode 102 Cathode 103 EL layer 111 Hole injection layer 112 Hole transport layer 112-1 First hole transport layer 112-2 Second hole transport layer 113 Light-emitting layer 114 Electron transport layer 114-1 First electron transport layer 114-2 Second electron transport layer 115 Electron injection layer 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 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 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 Display section 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. The device has an anode, a cathode, a light-emitting layer, and an electron transport layer, The electron transport layer comprises an electron transport material, the electron transport material is an organic compound having a first skeleton, a second skeleton, and a third skeleton; the first skeleton is any one of a quinoxaline ring, a dibenzo[h,g]quinoxaline ring, a triazine ring, and a benzofuropyrimidine ring; the second skeleton is any one of a naphthalene ring, a fluorene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a chrysene ring, a triphenylene ring, and a pyrene ring; the third skeleton is any one of a pyridine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring, the first skeleton is bonded to the second skeleton via a phenylene group; The third scaffold is directly bonded to the second scaffold.

2. The device has an anode, a cathode, a light-emitting layer, and an electron transport layer, The electron transport layer comprises an electron transport material, the electron transport material is an organic compound having a first skeleton, a second skeleton, and a third skeleton; the first skeleton is any one of a quinoxaline ring, a dibenzo[h,g]quinoxaline ring, a triazine ring, and a benzofuropyrimidine ring; the second skeleton is any one of a naphthalene ring, a fluorene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a chrysene ring, a triphenylene ring, and a pyrene ring; the third skeleton is any one of a pyridine ring substituted at the 3-position, a pyrimidine ring substituted at the 5-position, and a pyrazine ring; the first skeleton is bonded to the second skeleton via a phenylene group; The third scaffold is directly bonded to the second scaffold.

3. The device has an anode, a cathode, 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 comprises a hole transport material and an acceptor material; the electron transport layer comprises an electron transport material and a metal, a metal salt, a metal oxide, or an organometallic salt; the hole transport material is an organic compound having a hole transport property and a HOMO level of −5.7 eV or more and −5.4 eV or less; the acceptor material is a substance that exhibits electron accepting properties to the hole transport material, the electron transport material is an organic compound having a first skeleton, a second skeleton, and a third skeleton; the first skeleton is any one of a quinoxaline ring, a dibenzo[h,g]quinoxaline ring, a triazine ring, and a benzofuropyrimidine ring; the second skeleton is any one of a naphthalene ring, a fluorene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a chrysene ring, a triphenylene ring, and a pyrene ring; the third skeleton is any one of a pyridine ring, a pyrimidine ring, a pyrazine ring, and a triazine ring, the first skeleton is bonded to the second skeleton via a phenylene group; The third scaffold is directly bonded to the second scaffold.

4. The device has an anode, a cathode, 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 comprises a hole transport material and an acceptor material; the electron transport layer comprises an electron transport material and a metal, a metal salt, a metal oxide, or an organometallic salt; the hole transport material is an organic compound having a hole transport property and a HOMO level of −5.7 eV or more and −5.4 eV or less; the acceptor material is a substance that exhibits electron accepting properties to the hole transport material, the electron transport material is an organic compound having a first skeleton, a second skeleton, and a third skeleton; the first skeleton is any one of a quinoxaline ring, a dibenzo[h,g]quinoxaline ring, a triazine ring, and a benzofuropyrimidine ring; the second skeleton is any one of a naphthalene ring, a fluorene ring, an anthracene ring, a phenanthrene ring, a tetracene ring, a chrysene ring, a triphenylene ring, and a pyrene ring; the third skeleton is any one of a pyridine ring substituted at the 3-position, a pyrimidine ring substituted at the 5-position, and a pyrazine ring; the first skeleton is bonded to the second skeleton via a phenylene group; The third scaffold is directly bonded to the second scaffold.

5. In claim 3 or claim 4, A light-emitting device wherein the acceptor material is an organic compound.

6. In any one of claims 1 to 5, A light emitting device, wherein the third skeleton is bonded to the second skeleton such that a nitrogen is β to the carbon bonded to the second skeleton.

7. In any one of claims 1 to 6, The light-emitting device, wherein the electron transport layer further comprises a metal, a metal salt, a metal oxide, or an organometallic salt.

8. In claim 7, A light emitting device, wherein the metal, metal salt, metal oxide, or organometallic salt is a metal complex with an alkali metal or an alkaline earth metal.

9. In claim 7, A light emitting device, wherein the metal, metal salt, metal oxide, or organometallic salt is a metal complex having nitrogen- and oxygen-containing ligands and an alkali metal or alkaline earth metal.

10. In claim 7, The light-emitting device, wherein the metal, metal salt, metal oxide, or organometallic salt is a metal complex having a ligand containing an 8-hydroxyquinolinato structure and a monovalent metal ion.

11. In any one of claims 1 to 10, The light emitting device wherein the electron transport layer is in contact with the cathode.

12. In any one of claims 1 to 11, The light-emitting layer includes a host material and a light-emitting material, The light-emitting material is a blue fluorescent light-emitting device.

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

14. 13. An electronic device comprising: the light-emitting device according to claim 1; and a sensor, an operation button, a speaker, or a microphone.

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

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