Light-emitting device

Abstract

To provide a light-emitting device that is driven at low voltage.SOLUTION: A light-emitting device includes a first electrode, a second electrode, and an organic compound layer. The organic compound layer exists between the first electrode and the second electrode. The organic compound layer includes a light-emitting layer and an electron injection layer. The electron injection layer includes metal or metal oxide, a first organic compound, and a second organic compound. The first organic compound has a π-electron deficient type heterocyclic aromatic ring. The second organic compound includes two or more heterocyclic aromatic rings, in which the two or more heterocyclic aromatic rings are coupled or condensed, and include three or more hetero atoms in total. The second organic compound is polydentate by two or more among the three or more hetero atoms, and has a function of mutually operating on the metal or metal oxide.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] One aspect of the present invention relates to a light-emitting device.

[0002] Note that one aspect of the present invention is not limited to the above technical field. Examples of the technical field of one aspect of the present invention include semiconductor devices, display devices, light-emitting devices, power storage devices, storage devices, electronic devices, lighting devices, input devices (e.g., touch sensors), input / output devices (e.g., touch panels), their driving methods, or their manufacturing methods.

Background Art

[0003] In recent years, display devices have been developed for various applications. For example, as applications of large display devices, there are home television sets (also referred to as TVs or television receivers), digital signage, and PIDs (Public Information Displays). As applications of small display devices, the development of smartphones or tablet terminals equipped with touch panels is underway.

[0004] At the same time, higher definition of display devices is also required. As devices that require high-definition display devices, for example, devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR) are being actively developed.

[0005] As a display element used in a display device, the development of light-emitting devices (also referred to as light-emitting elements) has been actively promoted. Light-emitting devices (also referred to as EL devices or EL elements) that utilize the electroluminescence (hereinafter abbreviated as EL) phenomenon, particularly organic EL devices mainly using organic compounds, are suitable for display devices because they have characteristics such as being easily made thin and lightweight, being able to respond quickly to input signals, and being drivable using a DC constant voltage power supply.

[0006] In order to obtain a higher-definition light-emitting device using an organic EL device, instead of the vapor deposition method using a metal mask, patterning of the organic layer by a photolithography method using a photoresist or the like has been studied. By using the photolithography method, a high-definition display device with an EL layer interval of several μm can be obtained (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0008] It has been known that the EL layer of an organic EL device (also referred to as a light-emitting device in this specification) is affected in terms of initial characteristics and reliability when exposed to atmospheric components such as water and oxygen, and it has been common sense that its handling is carried out in an atmosphere close to a vacuum. In particular, for the electron injection layer, an alkali metal or alkaline earth metal, or a compound thereof is used, but these metals and compounds are highly reactive with water or oxygen, and when the surface of the EL layer is exposed to the atmosphere, it deteriorates instantaneously and no longer functions as an electron injection layer.

[0009] However, in the process of performing processing by the photolithography method as described above, it is inevitably necessary to expose the surface of the EL layer to the atmosphere.

[0010] In one aspect of the present invention, an object is to provide a novel light-emitting device. Or, in another aspect of the present invention, an object is to provide a light-emitting device having good efficiency. Or, in one aspect of the present invention, an object is to provide a light-emitting device having good reliability. Or, in another aspect of the present invention, an object is to provide a light-emitting device having good efficiency and reliability.

[0011] Or, in one aspect of the present invention, an object is to provide a novel light-emitting device manufactured through a photolithography process. Or, in another aspect of the present invention, an object is to provide a light-emitting device manufactured through a photolithography process and having good efficiency. Or, in one aspect of the present invention, an object is to provide a light-emitting device manufactured through a photolithography process and having good reliability. Or, in another aspect of the present invention, an object is to provide a light-emitting device manufactured through a photolithography process and having good light-emitting efficiency and reliability.

[0012] Or, in one aspect of the present invention, an object is to provide a novel light-emitting device that can be used in a high-definition display device. Or, in another aspect of the present invention, an object is to provide a light-emitting device that can be used in a high-definition display device and has good efficiency. Or, in one aspect of the present invention, an object is to provide a light-emitting device that can be used in a high-definition display device and has good reliability. Or, in another aspect of the present invention, an object is to provide a light-emitting device that can be used in a high-definition display device and has good light-emitting efficiency and reliability.

[0013] Alternatively, in another aspect of the present invention, it is an object to provide a highly reliable display device. Alternatively, in another aspect of the present invention, it is an object to provide a high-definition display device. Alternatively, in another aspect of the present invention, it is an object to provide a high-definition and highly reliable display device.

[0014] Note that the description of these problems does not prevent the existence of other problems. One aspect of the present invention does not necessarily need to solve all of these problems. It is possible to extract other problems from the description of the specification, drawings, and claims.

Means for Solving the Problems

[0015] One aspect of the present invention is a light-emitting device having a first electrode, a second electrode, and an organic compound layer, the organic compound layer being located between the first electrode and the second electrode, the organic compound layer having a light-emitting layer and an electron injection layer, the electron injection layer having a metal or metal oxide, a first organic compound, and a second organic compound, the first organic compound having a π-electron-deficient heteroaromatic ring, the second organic compound having two or more heteroaromatic rings, the two or more heteroaromatic rings being bonded or condensed to each other and having a total of three or more heteroatoms, and the second organic compound having a function of interacting with the metal or metal oxide in a polydentate manner by two or more of the three or more heteroatoms.

[0016] One aspect of the present invention is one of a plurality of light-emitting devices included in a group of light-emitting devices having a first electrode group formed on the same insulating surface, a second electrode facing the first electrode group, and a first layer group located between the first electrode group and the second electrode. The light-emitting device has a first electrode, a second electrode, and a first layer. The first electrode is one of the first electrode group, and the first electrode is independent for each of the plurality of light-emitting devices. The first layer is one of the first layer group, and the first layer is independent for each of the plurality of light-emitting devices. The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The second electrode and the first layer overlap the first electrode. The first layer has a light-emitting layer and an electron injection layer. The electron injection layer has a metal or metal oxide, a first organic compound, and a second organic compound. The first organic compound has a π-electron-deficient heteroaromatic ring. The second organic compound has two or more heteroaromatic rings. The two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms. The second organic compound has a function of interacting with the metal or metal oxide in a polydentate manner by two or more of the three or more heteroatoms. The distance between the first layer of the light-emitting device and the first layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

[0017] In one aspect of the above invention, the second organic compound has a function of interacting with the metal or metal oxide in a bidentate or tridentate manner by a heteroatom.

[0018] In one aspect of the above invention, the heteroatom is a nitrogen atom.

[0019] One aspect of the present invention is a light-emitting device having a first electrode, a second electrode, and an organic compound layer. The organic compound layer is located between the first electrode and the second electrode. The organic compound layer has a light-emitting layer and an electron injection layer. The electron injection layer has a metal or metal oxide, a first organic compound, and a second organic compound. The first organic compound has a π-electron-deficient heteroaromatic ring. The second organic compound is an organic compound represented by the general formula (G1-1).

[0020]

Chem.

[0021] In the above general formula (G1-1), A 1 , A 2 and A 3 each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, and A 1 , A 2 and A 3 may form a fused ring with each other.

[0022] One aspect of the present invention has a first electrode, a second electrode, and an organic compound layer. The organic compound layer is located between the first electrode and the second electrode, and the organic compound layer has a light-emitting layer and an electron injection layer. The electron injection layer has a metal or metal oxide, a first organic compound, and a second organic compound. The first organic compound has a π-electron deficient heteroaromatic ring, and the second organic compound is an organic compound represented by the general formula (G1-2). It is a light-emitting device.

[0023]

Chem.

[0024] In the above general formula (G1-2), A 1 , and A 2 each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, and A 1 , and A 2 may form a fused ring with each other, and A 1 has two or more nitrogen atoms.

[0025] In one aspect of the above invention, the heteroaromatic ring is a π-electron deficient heteroaromatic ring, and it is a light-emitting device.

[0026] In one aspect of the above invention, the heterocyclic aromatic ring includes at least one of a pyridine ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), a triazine ring, an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), and a triazole ring, and it is a light-emitting device.

[0027] In one aspect of the above invention, at least one of two or more heterocyclic aromatic rings includes a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring, and it is a light-emitting device.

[0028] In one aspect of the above invention, two or more heterocyclic aromatic rings include a total of three or more pyridine rings, and it is a light-emitting device.

[0029] In one aspect of the above invention, the first organic compound has an electron-donating group, and it is a light-emitting device.

[0030] In one aspect of the above invention, the electron-donating group is at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group, and it is a light-emitting device.

[0031] In one aspect of the above invention, the first organic compound has an acid dissociation constant pKa of 8 or more, and it is a light-emitting device.

[0032] In one aspect of the above invention, the first organic compound has a phenanthroline ring, and it is a light-emitting device.

[0033] In one aspect of the above invention, the second organic compound has a glass transition temperature T g of 100°C or higher, and it is a light-emitting device.

[0034] In one aspect of the above invention, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound, and it is a light-emitting device.

[0035] In one aspect of the above invention, the metal belongs to Group 1, Group 3, Group 11, or Group 13 in the periodic table, and it is a light-emitting device.

[0036] In one aspect of the above invention, the first layer is a mixture of a metal, a second organic compound, and a first organic compound, and it is a light-emitting device.

[0037] In one aspect of the above invention, the first layer is a laminate of a layer containing a metal and a layer containing a second organic compound or a first organic compound, and it is a light-emitting device.

[0038] Alternatively, another aspect of the present invention is a light-emitting device having a plurality of light-emitting devices. Each of the plurality of light-emitting devices is the light-emitting device described in any of the above. Each of the plurality of light-emitting devices has an organic compound layer including a light-emitting layer and an electron injection layer between a first electrode and a second electrode. The organic compound layers each of the plurality of light-emitting devices has are independent of each other among the plurality of light-emitting devices.

[0039] Alternatively, another aspect of the present invention is a display module having the above light-emitting device and at least one of a connector and an integrated circuit.

[0040] Alternatively, another aspect of the present invention is an electronic device having the above light-emitting device and at least one of a housing, a battery, a camera, a speaker, and a microphone.

Advantages of the Invention

[0041] According to one aspect of the present invention, a novel light-emitting device can be provided. Alternatively, according to another aspect of the present invention, a light-emitting device having good efficiency can be provided. Alternatively, according to one aspect of the present invention, a light-emitting device having good reliability can be provided. Alternatively, according to another aspect of the present invention, a light-emitting device having good efficiency and reliability can be provided.

[0042] Alternatively, according to one aspect of the present invention, a novel light-emitting device fabricated through a photolithography process can be provided. Alternatively, according to another aspect of the present invention, a light-emitting device fabricated through a photolithography process and having good efficiency can be provided. Alternatively, according to one aspect of the present invention, a light-emitting device fabricated through a photolithography process and having good reliability can be provided. Alternatively, according to another aspect of the present invention, a light-emitting device fabricated through a photolithography process and having good light-emitting efficiency and reliability can be provided.

[0043] Alternatively, according to one aspect of the present invention, a novel light-emitting device that can be used in a high-definition display device can be provided. Alternatively, according to another aspect of the present invention, a light-emitting device that can be used in a high-definition display device and has good efficiency can be provided. Alternatively, according to one aspect of the present invention, a light-emitting device that can be used in a high-definition display device and has good reliability can be provided. Alternatively, according to another aspect of the present invention, a light-emitting device that can be used in a high-definition display device and has good light-emitting efficiency and reliability can be provided.

[0044] Alternatively, according to another aspect of the present invention, a highly reliable display device can be provided. Alternatively, according to another aspect of the present invention, a high-definition display device can be provided. Alternatively, according to another aspect of the present invention, a high-definition and highly reliable display device can be provided.

[0045] Alternatively, a novel organic compound, a novel light-emitting device, a novel display device, a novel display module, and a novel electronic device can be provided.

[0046] Note that the description of these effects does not preclude the existence of other effects. One aspect of the present invention does not necessarily have to have all of these effects. It is possible to extract other effects from the descriptions in the specification, drawings, and claims.

Brief Description of the Drawings

[0047]

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Mode for Carrying Out the Invention

[0048] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the form and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments shown below.

[0049] In this specification and the like, a device manufactured using a metal mask or an FMM (fine metal mask, high-definition metal mask) may be referred to as a device having an MM (metal mask) structure. Also, in this specification and the like, a device manufactured without using a metal mask or an FMM may be referred to as a device having an MML (metal maskless) structure.

[0050] (Embodiment 1) Figure 1(A) is a schematic diagram of a light-emitting device according to an aspect of the present invention. On an insulator 109, a first electrode 101 is provided, and an organic compound layer (also referred to as an EL layer) 103 is provided between the first electrode 101 and a second electrode 102. The organic compound layer 103 has at least a light-emitting layer 113 and an electron injection layer 115. The light-emitting layer 113 is a layer containing a light-emitting substance and emits light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0051] In addition to the light-emitting layer 113 and the electron injection layer 115, the organic compound layer 103 preferably has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 114 as shown in FIG. 1(A). Note that the organic compound layer 103 may include functional layers other than the above-described functional layers, such as a hole blocking layer, an exciton blocking layer, and an intermediate layer. Conversely, any of the above-described layers may not be provided.

[0052] Here, as one method of forming an organic film into a predetermined shape, a vacuum evaporation method (mask evaporation) using a metal mask is widely used. However, these days, as high density and high definition progress, due to various reasons typified by the problem of alignment accuracy and the problem of the arrangement interval with the substrate, further high definition is approaching its limit in mask evaporation. On the other hand, by processing the shape of an organic film using a photolithography method, the realization of an organic semiconductor device having a denser pattern is expected. Furthermore, since the photolithography method is easier to increase the area than mask evaporation, research on the processing of an organic film using the photolithography method has been advanced.

[0053] On the other hand, it has been known that the EL layer in an organic EL device has an influence on the initial characteristics or reliability when exposed to atmospheric components such as water and oxygen, and it has been common sense that its handling is performed in an atmosphere close to vacuum.

[0054] In particular, an alkali metal, an alkaline earth metal, or a compound thereof (hereinafter also referred to as a Li compound, etc.) is often used for the electron injection layer of a light-emitting device. However, these Li compounds, etc. have high reactivity with water or oxygen and deteriorate instantaneously just by being exposed to the atmosphere, losing their function as an electron injection layer.

[0055] However, in the process of performing processing by the photolithography method as described above, it is inevitably necessary to expose the surface of the EL layer to the atmosphere. For this reason, when processing is performed by the photolithography method, the electron injection property of the electron injection layer using an alkali metal compound or the like is greatly reduced. As a result, an organic EL device having an electron injection layer using an alkali metal compound or the like and subjected to processing by the photolithography method has an increased driving voltage and it has been difficult to obtain good characteristics.

[0056] Therefore, one aspect of the present invention is to use, as the electron injection layer 115, a metal or a metal oxide, a first organic compound having a π-electron deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms, so that an organic EL device having good characteristics can be obtained even after passing through a photolithography process involving exposure of the organic compound layer to the atmosphere.

[0057] With this configuration, in the electron injection layer 115, the first organic compound functions as an electron donor (electron provider) with respect to the second organic compound, and a donor level (singly occupied molecular orbital (SOMO) level or highest occupied molecular orbital (HOMO) level) is formed by the interaction of the first organic compound, the metal or metal oxide, and the second organic compound. By the interaction of the first organic compound, the metal or metal oxide, and the second organic compound, the donor level (SOMO level or HOMO level) becomes a high energy level, and the electron injection barrier from the electron injection layer to the electron transport layer can be reduced. Further, due to this interaction, electrons can be smoothly injected and transported from the electron injection layer 115 to the electron transport layer 114, so that a light-emitting device with a low driving voltage can be manufactured.

[0058] Note that the LUMO level and HOMO level of an organic compound are generally estimated by cyclic voltammetry (CV), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values between different compounds, it is preferable to use values estimated by the same measurement for comparison.

[0059] Also, the SOMO level is an orbital derived from the unpaired electrons of the metal, and can be distributed on the orbitals of the first organic compound and the second organic compound by the interaction of the metal or metal oxide, the first organic compound, and the second organic compound. That is, it can be said that the electron orbitals of the metal or metal oxide and the electron orbitals of the organic compound interact.

[0060] In addition, organic compounds containing many atoms that can interact with each other can interact more stably with metals or metal oxides. Therefore, the second organic compound used in one embodiment of the present invention is preferably a material having two or more coordination sites, such as three or more coordination sites, that interact with metals or metal oxides. Since an organic compound that interacts with a metal at multiple coordination sites is stabilized when it interacts with a metal or metal oxide, it is possible to form an electron injection layer that is resistant to oxygen and water in the air, as well as water and chemical solutions used during the process in the lithography method.

[0061] Examples of the interacting atoms include heteroatoms having unshared electron pairs in the organic compound. For example, oxygen (O), nitrogen (N), sulfur (S), and phosphorus (P) can be mentioned, and nitrogen is preferred. Since nitrogen has a high electronegativity, it is likely to interact with metals or metal oxides. In addition, since nitrogen can form a conjugated bond in the organic compound, by using nitrogen in the molecule, particularly in a heteroaromatic ring, an organic compound with high carrier transportability can be obtained. The heteroaromatic ring is more preferably an even-membered ring such as a 6-membered ring or an 8-membered ring. With this configuration, the unshared electron pair on nitrogen does not participate in conjugation, so it is more likely to interact with metals or metal oxides.

[0062] The metal or metal oxide, the first organic compound, and the second organic compound can, by interacting with each other, form a donor level (SOMO level or HOMO level), reduce the electron injection barrier to the electron transport layer, and smoothly inject and transport electrons from the electron injection layer to the electron transport layer. The heteroaromatic ring of the second organic compound is preferably a π-electron-deficient heteroaromatic ring. With such a structure, the second organic compound can have electron transporting properties and can smoothly inject and transport electrons from the electron injection layer to the electron transport layer. Further, since the second organic compound has two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more nitrogen atoms, the LUMO level of the second organic compound can be made lower than the LUMO level of the first organic compound. By using a material having a LUMO level lower than the LUMO level of the first organic compound as the second organic compound, it can be stabilized when interacting with the metal or metal oxide, the first organic compound, and the second organic compound.

[0063] In addition, the first organic compound preferably has a π-electron-deficient heteroaromatic ring having a lone pair of electrons. With such a structure, it can interact stably with the metal or metal oxide. Further, the first organic compound preferably has two or more π-electron-deficient heteroaromatic rings having a lone pair of electrons, and is a material that interacts with the metal or metal oxide in a bidentate or more multidentate manner. An organic compound that interacts with the metal or metal oxide in a bidentate or more multidentate manner is stabilized when interacting with the metal or metal oxide.

[0064] Further, the first organic compound preferably has an electron-donating substituent. With such a structure, since the first organic compound can have a high HOMO level and LUMO level, the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound can be increased. Therefore, it is more stabilized when interacting with the metal or metal oxide, the first organic compound, and the second organic compound.

[0065] As described above, since it can be stabilized when interacting with the first organic compound and the second organic compound, even through a photolithography process involving exposure of the EL layer to the atmosphere, it is possible to smoothly inject and transport electrons from the electron injection layer to the adjacent electron transport layer. Therefore, it becomes possible to fabricate a light-emitting device with suppressed increase in driving voltage, good luminous efficiency, and good reliability using a photolithography process.

[0066] In addition, metals with low work functions typified by alkali metals and alkaline earth metals, and these compounds have high reactivity with oxygen or water. When used in a light-emitting device processed by a lithography method, it may cause a decrease in luminous efficiency, an increase in driving voltage, a decrease in driving life, and the occurrence of shrinkage (non-light-emitting region at the end of the light-emitting part), leading to a deterioration in the characteristics or reliability of the light-emitting device.

[0067] On the other hand, in one aspect of the present invention, even when using an alkali metal, an alkaline earth metal, and these compounds, a first organic compound having a π-electron-deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms, interact with each other to be stabilized. Thus, it is possible to form an electron injection layer that is resistant to oxygen and water in the atmosphere, as well as water and chemical solutions used during the process in the lithography method.

[0068] By using an alkali metal, an alkaline earth metal, and these compounds as the metal in one aspect of the present invention, it is possible to make the donor level (SOMO level or HOMO level) formed by the interaction with a first organic compound having a π-electron-deficient heteroaromatic ring and a second organic compound having two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms, have a high energy. This can reduce the electron injection barrier from the electron injection layer to the electron transport layer and form a configuration that can smoothly inject and transport electrons from the electron injection layer to the electron transport layer, which is preferable.

[0069] In addition, among transition metals (metal elements of Groups 3 to 11) and typical metals, metal elements of Groups 12 to 14 have low reactivity with oxygen and water in the atmosphere, as well as water and chemical solutions used in the lithography process. Therefore, when used in a light-emitting device, they have less deterioration due to water and oxygen, which is a concern when using a metal with a small work function. On the other hand, since the metal is stable and has low electron injection properties, it causes a decrease in the luminous efficiency of the light-emitting device, an increase in the driving voltage, a decrease in the driving life, etc.

[0070] The electron injection layer in one aspect of the present invention uses a metal element of Groups 12 to 14 among transition metals (metal elements of Groups 3 to 11) and typical metals, a first organic compound having a π-electron deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms, and interact with each other to form a donor level (SOMO level or HOMO level). That is, it is a configuration that reduces the electron injection barrier from the electron injection layer to the electron transport layer and smoothly injects and transports electrons from the electron injection layer to the electron transport layer. In addition, since the configuration has resistance to oxygen and water in the atmosphere, as well as water and chemical solutions used during the process in the lithography method, one aspect of the present invention can provide a light-emitting device with excellent moisture resistance, water resistance, oxygen resistance, chemical resistance, a low driving voltage, and good luminous efficiency.

[0071] [Analysis of the Interaction between a Metal or Metal Oxide and an Organic Compound by Quantum Chemical Calculations] Here, an analysis by quantum chemical calculations was performed on the case where a metal or metal oxide, a first organic compound having electron-donating properties and having non-bonding electron pairs, and a second organic compound having electron-transporting properties interacted with each other.

[0072] [Estimation of the Interaction between a Metal or Metal Oxide and an Organic Compound] Here, quantum chemical calculations were performed on the spin density and electrostatic potential (ESP) when a metal or metal oxide, a first organic compound having a π-electron-deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or fused to each other and have a total of three or more heteroatoms, interacted with each other. As the first organic compound, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) was used, and as the second organic compound, 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy) was used, and calculations were performed using lithium (Li) as the metal.

[0073] As the quantum chemical calculation program, Gaussian09 was used. The calculations were performed using an SGI8600 manufactured by HPE. The most stable structures in the ground states of each of the first organic compound and the second organic compound alone, and of the composite material of the first organic compound, the second organic compound, and the metal or metal oxide, were calculated by the density functional theory (DFT). The 6-311G(d,p) basis function was used, and the B3LYP functional was used. Note that the total energy of DFT is represented by the sum of the potential energy, the electrostatic energy between electrons, the kinetic energy of electrons, and the exchange-correlation energy that includes all complex electron-electron interactions. In DFT, the exchange-correlation interaction is approximated by a functional of the one-electron potential represented by the electron density (the meaning of a function of a function), so the calculations are highly accurate.

[0074] The analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6'(P-Bqn)2BPy), and the metal (Li) are shown in Figure 2. The spheres in the figure represent the atoms constituting the compound, and the cloud-like substances existing around the atoms have a density value of 0.0004e / a0 in the atomic unit system 3 (e is the elementary charge (1e = 1.60218×10 -19C), where a0 is the Bohr radius (1a0 = 5.29177×10 -11 m), represents the spin density distribution. Since the ground states of the first organic compound (Pyrrd-Phen) and the second organic compound (6,6’(P-Bqn)2BPy) are singlet ground states, no spin density distribution is observed.

[0075] In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) according to one aspect of the present invention, the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) interact with each other, and the metal (Li) coordinates to the nitrogen atoms (nitrogen atoms (N) at the 1st and 10th positions) having unshared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), and the nitrogen atoms having unshared electron pairs in the pyridine ring and the benzo[h]quinazoline ring of the second organic compound (6,6’(P-Bqn)2BPy), thereby stabilizing and forming a composite material. Therefore, as shown in Figure 2, it can be seen that the spin derived from the unpaired electrons of the metal (Li) is localized in the second organic compound (6,6’(P-Bqn)2BPy). Also, no spin density distribution is observed in the metal (Li). From this, it can be seen that due to the interaction of the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li), the second organic compound (6,6’(P-Bqn)2BPy) is in a radical anion state.

[0076] Next, the analysis results of the electrostatic potential map in the ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) are shown in Figure 3. The spheres in the figure represent the atoms constituting the compound, and the cloud-like substances existing around the atoms have a density value of 0.0004e / a0 in the atomic unit system 3It represents the electrostatic potential in the electron density distribution when [conditions are met]. The electrostatic potential is the interaction energy between a positive point charge with a unit electric charge and the electron distribution of the molecule. The electrostatic potential map represents the electrostatic potential on the isoelectron density surface in color. Regions with negative electrostatic potential are represented in red, and positive regions are represented in blue. Atoms in regions with negative electrostatic potential have negative charges, and atoms in positive regions have positive charges. However, since Figure 3 is a grayscale image, to indicate the regions with negative and positive electrostatic potential, the dark red part (i.e., the region with negative electrostatic potential) is surrounded by a dotted line, and the dark blue part (i.e., the region with positive electrostatic potential) is surrounded by a dashed line.

[0077] In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) of one aspect of the present invention, the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) interact with each other. The metal (Li) coordinates to the nitrogen atoms (nitrogen atoms at the 1st and 10th positions (N)) having unshared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), and the nitrogen atoms having unshared electron pairs in the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6’(P-Bqn)2BPy), thereby stabilizing and forming a composite material. As a result, as shown in Figure 3, it can be seen that positive electrostatic potential is mainly distributed on the metal (Li) and the first organic compound (Pyrrd-Phen), and negative electrostatic potential is mainly distributed on the second organic compound (6,6’(P-Bqn)2BPy). Also, it can be seen that the electrostatic potential of the nitrogen atoms having unshared electron pairs in the pyridine ring and benzo[h]quinazoline ring of the second organic compound (6,6’(P-Bqn)2BPy) is negative, while the electrostatic potential of the metal (Li) is positive. The Mulliken partial charge of the Li atom was +0.691e in the atomic unit system.

[0078] [Estimation of SOMO Level or Stabilization Energy] Next, quantum chemical calculations were performed to estimate the stabilization energy when a metal or metal oxide, a first organic compound having a π-electron-deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or fused to each other and have a total of three or more heteroatoms, interact with each other, and the SOMO level formed at that time.

[0079] Gaussian09 was used as the quantum chemical calculation program. The calculations were performed using an SGI8600 manufactured by HPE. First, the ground states of the first organic compound, the second organic compound, and the metal or metal oxide, respectively, and the most stable structures in the ground states of the composite materials of the first organic compound and the metal or metal oxide, the composite materials of the second organic compound and the metal or metal oxide, and the composite materials of the first organic compound, the second organic compound, and the metal or metal oxide were calculated by the density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as the basis functions, and B3LYP was used as the functional. Next, the stabilization energy was calculated from the difference between the total energy of the composite material of the organic compound and the metal or metal oxide and the sum of the total energy of the organic compound alone and the total energy of the metal or metal oxide alone. That is, (Stabilization energy) = (Total energy of the composite material of the organic compound and the metal or metal oxide) - (Total energy of the organic compound alone) - (Total energy of the metal or metal oxide alone).

[0080] For the calculations, lithium (Li) was used as the metal or metal oxide, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) was used as the first organic compound, and 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy) was used as the second organic compound. The results of the calculations of the composite materials are shown in Table 1 below. Also, for comparison, lithium (Li) was used as the metal or metal oxide, Pyrrd-Phen was used as the first organic compound, and instead of 6,6'(P-Bqn)2BPy as the second organic compound, 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen) was used. The calculation results of the composite materials using lithium (Li) and Pyrrd-Phen, the calculation results of the composite materials using lithium (Li) and 6,6'(P-Bqn)2BPy, and the calculation results of the composite materials using lithium (Li) and NBphen are also listed. Note that 6,6'(P-Bqn)2BPy is a second organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms. On the other hand, NBphen is an organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or condensed to each other but have a total of less than three heteroatoms.

[0081]

Table 1

[0082]

Table 2

[0083] From Table 1 above, the stabilization energy of the composite material of lithium (Li), the first organic compound (Pyrrd-Phen), and the second organic compound (6,6’(P-Bqn)2BPy) in one aspect of the present invention has a large absolute value of negative. This indicates that when the organic compound and the metal interact, the energy is more stable compared to the case where the organic compound and the metal do not interact. The SOMO level formed at this time is higher than the HOMO levels of the first organic compound (Pyrrd-Phen) and the second organic compound (6,6’(P-Bqn)2BPy) shown in Table 2, and the difference from their respective LUMO levels is small, which is preferable because of excellent electron injection properties. Note that the energy levels of the SOMO level, HOMO level, and LUMO level in Table 1 and Table 2 are values obtained by calculation, and the absolute values may be different from the actual measurement.

[0084] On the other hand, although not as much as the composite material of lithium (Li), the first organic compound (Pyrrd-Phen), and the second organic compound (6,6’(P-Bqn)2BPy) described above, the composite material of lithium (Li), the first organic compound (Pyrrd-Phen), and NBphen also has a negative stabilization energy, and when the organic compound and the metal interact, the energy is more stable compared to the case where the organic compound and the metal do not interact.

[0085] In addition, the composite material of lithium (Li) and the first organic compound (Pyrrd-Phen) has a negative stabilization energy, and among the composite materials having the second organic compound in addition to the composite material, the one with the second organic compound is more stable.

[0086] In addition, the composite material of lithium (Li) and the second organic compound (6,6’(P-Bqn)2BPy) has a slightly lower SOMO level, and when it further has the first organic compound, it has better electron injection properties. Also, the composite material of lithium (Li) and NBphen has a negative stabilization energy, and when it further has the first organic compound, it is more stable, and since the SOMO level is low, when it further has the first organic compound, it has better electron injection properties. That is, the composite material using a metal or metal oxide, a first organic compound having a π-electron deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms in the aspect of the present invention is stable and has excellent electron injection properties, and can be said to be suitable for an electron injection layer.

[0087] Next, the results of calculations of composite materials using metals belonging to Group 11 and Group 13 as the metal or metal oxide, specifically silver (Ag) and indium (In), Pyrrd-Phen as the first organic compound, 4′,4″″-(1,4-phenylene)bis(2,2′:6′,2″-terpyridine) (abbreviation: tPy2P), and 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn) as the second organic compound are shown in the following table. Also, for comparison, the results of calculations of composite materials using silver (Ag) and indium (In) as the metal or metal oxide, Pyrrd-Phen as the first organic compound, and NBphen instead of the second organic compound are also shown. Note that tPy2P and 2Py3Tzn are second organic compounds having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms. On the other hand, NBphen is an organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or condensed to each other but have less than three heteroatoms in total.

[0088]

Table 3

[0089]

Table 4

[0090] As shown in the above table, the composite material of the metal belonging to Group 11 and Group 13, the first organic compound, and the second organic compound in one aspect of the present invention has a large stabilization energy and a stable structure, so it is preferable. Further, the SOMO level formed at this time is high and it is preferable because of excellent electron injection property.

[0091] In consideration of the manufacturing process of the light-emitting device, generally, the EL layer of the light-emitting device, particularly the electron injection layer, is often formed by vacuum evaporation. At this time, as the material to be used, it is preferable to use a material that can be easily vacuum-evaporated, that is, a material having a low melting point. Since the metals of Group 11 elements and Group 13 elements have a low melting point, they can be suitably used for vacuum evaporation. Further, the metals of Group 11 elements and Group 13 elements are stable to oxygen and water in the air, which is preferable. Further, by using the vacuum evaporation method, the metal atoms and the organic compound can be easily mixed, which is preferable.

[0092] Further, Ag and In can also be used as the cathode material. It is preferable because the light-emitting device can be easily manufactured by using the same material for the electron injection layer and the cathode. Further, the manufacturing cost of the light-emitting device can be reduced.

[0093] From the above, it can be understood that a combination in which a first organic compound having a π-electron-deficient heteroaromatic ring, a metal or metal oxide, and a second organic compound having two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or fused to each other and have a total of three or more heteroatoms, interact with each other, and the first organic compound and the metal or metal oxide function as an electron donor with respect to the second organic compound. One aspect of the present invention is to use the material of this combination for an electron injection layer, so that an electron injection layer having good electron injection characteristics and resistance to oxygen and water in the air, and water and chemical solutions used during the process in a lithography method can be formed, thereby reducing the driving voltage and obtaining a light-emitting device with high luminous efficiency.

[0094] ≪Electron injection layer≫ As shown in Fig. 1(A), the electron injection layer 115 is provided between the second electrode 102 which is a cathode and the light-emitting layer 113, and includes a metal or metal oxide, a first organic compound having a π-electron-deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or fused to each other and have a total of three or more heteroatoms.

[0095] 〈Metal〉 As the metal, a typical metal or a transition metal can be used.

[0096] As the typical metal, an alkali metal (Group 1 element) such as Li, Na, K, Cs, an alkaline earth metal (Group 2 element) such as Mg, Ca, Ba, a Group 12 element such as Zn, a Group 13 element such as Al, In, a Group 14 element such as Sn, or a compound thereof can be used.

[0097] By using an alkali metal, an alkaline earth metal, and a compound thereof as the metal, the donor level formed by interacting with the first organic compound and the second organic compound can be set to a high energy level, electrons can be smoothly injected and transported from the electron injection layer to the electron transport layer, and a light-emitting device with a low driving voltage and high efficiency can be provided, which is preferable.

[0098] As the transition metal, a Group 3 element containing lanthanoids such as Y, Eu, Yb, a Group 7 element such as Mn, a Group 8 element such as Fe, a Group 9 element such as Co, a Group 10 element such as Ni, Pt, a Group 11 element such as Cu, Ag, Au, or a compound thereof can be used. The transition metal is preferable because it has low reactivity with components such as water and oxygen in the atmosphere.

[0099] Among the above, it is more preferable to use a metal belonging to an odd group (Group 1, Group 3, Group 5, Group 7, Group 9, Group 11 or Group 13). Among these odd-group transition metals, a metal having one electron (unpaired electron) in the outermost shell orbital is particularly preferable because it easily forms a SOMO with the first organic compound.

[0100] In addition, a metal having a low melting point and capable of forming a film by a vacuum evaporation method is preferable because it can easily form a mixed layer with an organic compound. Specifically, for example, metals of Group 11 elements and Group 13 elements have a low melting point and can be suitably used for vacuum evaporation. Also, metals of Group 11 elements and Group 13 elements are stable in oxygen and water in the atmosphere and are preferable.

[0101] 〈The first organic compound〉 As the first organic compound, an organic compound having a π - electron - deficient heteroaromatic ring can be used. Further, in order for the first organic compound to interact with a metal or metal oxide and function as an electron donor (electron donation) to the second organic compound, it is preferable that the π - electron - deficient heteroaromatic ring has a lone pair of electrons, and it is preferable that the lone pair of electrons has electron - donating properties. That is, the first organic compound preferably has a basic π - electron - deficient heteroaromatic ring. Further, since nitrogen has a high electronegativity, it easily interacts with a metal or metal oxide. Also, since nitrogen can form a conjugated bond in an organic compound, by using nitrogen in the molecule, particularly in a heteroaromatic ring, an organic compound with high carrier transportability can be obtained. Therefore, the first organic compound preferably has a heteroaromatic ring containing nitrogen. Incidentally, it is more preferable that the heteroaromatic ring is an even - numbered ring such as a 6 - membered ring or an 8 - membered ring. With such a configuration, the lone pair of electrons on nitrogen does not participate in conjugation, so that it easily interacts with a metal or metal oxide. Also, in order to smoothly inject and transport electrons from the electron injection layer to the electron transport layer, the first organic compound preferably has electron - transporting properties. Specifically, for example, the first organic compound preferably has a pyridine ring.

[0102] Also, a material in which the first organic compound has two or more π - electron - deficient heteroaromatic rings having a lone pair of electrons, and the two or more π - electron - deficient heteroaromatic rings are bonded or condensed with each other is preferable. By doing so, when interacting with a metal or metal oxide with two - dentate or multi - dentate of two or more dentates with the first organic compound and the second organic compound, it stabilizes, so that an electron injection layer that is not easily deteriorated even through a photolithography process involving air exposure can be formed. Specifically, for example, the first organic compound preferably has a heteroaromatic ring containing two or more pyridine rings. Among them, an organic compound having a bipyridine skeleton is preferable because a nitrogen atom easily coordinates with a metal and thus easily interacts with a metal or metal oxide.

[0103] Furthermore, the phenanthroline ring is preferable because it is rigid and highly stable. In particular, among phenanthroline rings, an organic compound having a 1,10-phenanthroline ring is preferable because the two nitrogen atoms it contains can coordinate to a metal, and thus an interaction with a metal or metal oxide is likely to occur.

[0104] In addition, the first organic compound may have a structure in which a plurality of phenanthroline rings are linked via a single bond or a divalent group. Specific examples of the divalent group include, for example, an alkylene group and an arylene group.

[0105] The alkylene group represents a divalent group obtained by removing two hydrogen atoms from an alkane. Specific examples of the alkylene group include divalent groups having a structure in which one more hydrogen atom is removed from the specific examples of the alkyl group described later.

[0106] The arylene group represents a divalent group obtained by removing two hydrogen atoms from an aromatic hydrocarbon. Specific examples thereof include divalent groups having a structure in which one more hydrogen atom is removed from the specific examples of the aryl group described later. The arylene group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0107] In addition, the first organic compound preferably has an electron-donating substituent. By doing so, since the first organic compound can have a high HOMO level and LUMO level, the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound can be increased, and when interacting with a metal or metal oxide, the first organic compound, and the second organic compound, it can be more stabilized, and an electron injection layer that is less likely to deteriorate even after undergoing a photolithography process involving exposure to the atmosphere can be formed.

[0108] Furthermore, as the first organic compound, it is more preferable to use an organic compound having a phenanthroline ring with an electron-donating group. In particular, by introducing an electron-donating group into the 1,10-phenanthroline ring, the electron density of the phenanthroline ring can be increased, and the efficiency of the interaction with a metal or metal oxide can be enhanced. Furthermore, it is preferable that at least one of the 4-position and 7-position of the 1,10-phenanthroline ring has an electron-donating group. By introducing an electron-donating group at the 4-position and 7-position, the electron density of the nitrogen atoms at the 1-position and 10-position in the para-position can be increased. In addition, while avoiding the steric congestion around the nitrogen atoms at the 1-position and 10-position, the electron density around them can be increased. Therefore, the interaction with a metal or metal oxide can be easily caused, which is preferable.

[0109] Specific examples of the electron-donating group include an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, a heterocyclic amino group, and the like. However, the preferred electron-donating groups for introduction into a π-electron-deficient heteroaromatic ring such as a phenanthroline ring are not limited to these. Any group that can increase the electron density of a π-electron-deficient heteroaromatic ring such as a phenanthroline ring by introduction can be applied as an electron-donating group. Further, the electron-donating group may be introduced into a π-electron-deficient heteroaromatic ring such as a phenanthroline ring via an arylene group such as a phenylene group, and the p-phenylene group is preferred as the arylene group.

[0110] The alkyl group refers to an alkane (C n H 2n+2) represents a monovalent group obtained by removing one hydrogen atom from it. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, isobutyl group, tert-butyl group, pentyl group, isopentyl group, sec-pentyl group, tert-pentyl group, neopentyl group, hexyl group, isohexyl group, sec-hexyl group, tert-hexyl group, neohexyl group, 3-methylpentyl group, 2-methylpentyl group, 2-ethylbutyl group, 1,2-dimethylbutyl group, 2,3-dimethylbutyl group, and the like.

[0111] The alkoxy group represents a monovalent group having a structure in which an alkyl group is bonded to an oxygen atom. Specific examples of the alkoxy group include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, sec-butoxy group, isobutoxy group, tert-butoxy group, n-pentyloxy group, isopentyloxy group, sec-pentyloxy group, tert-pentyloxy group, neopentyloxy group, n-hexyloxy group, isohexyloxy group, sec-hexyloxy group, tert-hexyloxy group, neohexyloxy group, and the like.

[0112] The aryloxy group represents a monovalent group having a structure in which an aryl group is bonded to an oxygen atom. Further, the aryl group represents a monovalent group obtained by removing one hydrogen atom from among the carbon atoms forming the ring of a monocyclic or polycyclic aromatic compound. Specific examples of the aryloxy group include phenoxy group, o-tolyloxy group, m-tolyloxy group, p-tolyloxy group, mesityloxy group, o-biphenyloxy group, m-biphenyloxy group, p-biphenyloxy group, 1-naphthyloxy group, 2-naphthyloxy group, 2-fluorenyloxy group, and the like. Note that the aryloxy group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0113] An alkylamino group represents a monovalent group obtained by removing one hydrogen from the nitrogen atom of a primary or secondary amine in which one or two alkyl groups are bonded to the nitrogen atom. Specific examples of the alkylamino group include, for example, a dimethylamino group, a diethylamino group, and the like.

[0114] An arylamino group represents a monovalent group obtained by removing one hydrogen from the nitrogen atom of a primary or secondary amine in which one or two aryl groups are bonded to the nitrogen atom. Specific examples of the arylamino group include a diphenylamino group, a bis(α-naphthyl)amino group, a bis(m-tolyl)amino group, and the like. Note that the arylamino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0115] Note that an amino group having a structure in which both an alkyl group and an aryl group are bonded to the nitrogen atom can be said to be either an alkylamino group or an arylamino group. Specific examples of such an amino group include, for example, an N-methyl-N-phenylamino group and the like.

[0116] A heterocyclic amino group represents a monovalent group obtained by removing one hydrogen atom from one of the nitrogen atoms forming the ring of a heterocyclic amine. Here, the heterocyclic amine represents a monocyclic or polycyclic heterocyclic compound, and at least one of the atoms forming the ring is a nitrogen atom bonded to a hydrogen atom. Specific examples of the heterocyclic amino group include groups represented by the following structural formulas (R-1) to (R-26). Note that the heterocyclic amino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0117]

Chemical formula

[0118] In addition, when the heterocyclic amino group has aromaticity, the lone pair electrons of the nitrogen atom contribute to the aromaticity. As a result, compared with the case where the lone pair electrons of the nitrogen atom do not contribute to the aromaticity, the electron-donating property to the phenanthroline ring may decrease. Therefore, among the above-mentioned heterocyclic amino groups, a heterocyclic amino group in which the lone pair electrons of the nitrogen atom do not contribute to the aromaticity is more preferable. Specifically, a group represented by the structural formula (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17) or (R-21) is more preferable as the electron-donating group. Among them, a group represented by the structural formula (R-3), (R-4), (R-8) or (R-21) has high electron-donating property and can increase the electron density of the phenanthroline ring more preferably.

[0119] In addition, as specific examples of the electron-donating group, groups represented by the following structural formulas (R-27) and (R-28) can be mentioned.

[0120] [Chemical formula]

[0121] The organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound may have both the above-mentioned electron-donating group and other substituents. In addition to the above-mentioned electron-donating group, specific examples of the substituents that can be introduced into the π-electron-deficient heteroaromatic ring include aryl groups. Specific examples of the aryl group include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, 1-naphthyl group, 2-naphthyl group, 2-fluorenyl group and the like. The aryl group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group and the like.

[0122] Specific examples of the organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound are shown in Structural Formulas (100) to (110). Note that the organic compound that can be used as the first organic compound is not limited thereto.

[0123]

Chemical Formula

[0124] Note that when the minimum value of the electrostatic potential (ESP: Electrostatic Potential) of the first organic compound is small (the absolute value of the negative is large), the stability of the interaction with a metal or metal oxide becomes high, which is preferable. In an organic compound having a π-electron-deficient heteroaromatic ring, the electrostatic potential around the nitrogen atom of the π-electron-deficient heteroaromatic ring tends to be negative. However, by introducing an electron-donating group into the π-electron-deficient heteroaromatic ring, the electrostatic potential around the nitrogen atom of the π-electron-deficient heteroaromatic ring can be further decreased (the absolute value of the negative is increased). Note that the electrostatic potential is the interaction energy between a positive point charge having a unit electric charge and the electron distribution of the molecule. Also, the value of the electrostatic potential changes depending on the threshold value of the electron density distribution. To enhance the efficiency of the interaction with a metal or metal oxide, the minimum value of the electrostatic potential of the first organic compound is preferably smaller (more negative) than the minimum value of the electrostatic potential of a phenanthroline ring having no substituent. Specifically, when the threshold value of the electron density distribution in the atomic unit system is 0.0004e / a0 3 the minimum value of the electrostatic potential is -0.085E h (E h represents Hartree energy (1E h = 27.211 eV)) or less is preferable, and -0.090E h or less is more preferable. Also, when the threshold value of the electron density distribution is 0.003e / a0 3 the minimum value of the electrostatic potential is preferably -0.12E h or less, and -0.13E h or less is more preferable.

[0125] Estimation of Properties of the First Organic Compound by Quantum Chemical Calculations An estimation of the minimum value of the electrostatic potential (ESP) of an organic compound that can be used for the above-mentioned first organic compound was performed by quantum chemical calculations.

[0126] Gaussian09 was used as the quantum chemical calculation program. The calculations were performed using an SGI8600 manufactured by HPE. The most stable structure in the ground state of the first organic compound was calculated by the density functional theory (DFT). 6-311G(d,p) was used as the basis function and B3LYP was used as the functional.

[0127] The analysis results of the electrostatic potential in the ground state of the first organic compound are shown in the following table. Note that the electrostatic potential is the interaction energy between a positive point charge with a unit electric charge and the electron distribution of the molecule. Also, the value of the electrostatic potential changes depending on the threshold value of the electron density distribution. In the following table, the threshold value of the electron density distribution in the atomic unit system is 0.0004e / a0 3 or 0.003e / a0 3 and the electrostatic potential in the electron density distribution when this is the case is shown.

[0128] [Table 5]

[0129] Note that the structural formulas of the organic compounds represented by structural formulas (100) to (107) in the table, which are shown as organic compounds that can be used for the first organic compound, and the structural formulas of Bphen, mPPhen2P, NBphen, and Phen are shown below.

[0130] [Chemical Formula]

[0131] From the above table, for the organic compounds represented by structural formulas (100) to (103), when the threshold value of the electron density distribution in the atomic unit system is 0.0004 e / a0 3 the minimum value of ESP is -0.085 E h or less, and it was found to be most preferable for use in the first organic compound. On the other hand, the minimum value of ESP of the organic compounds represented by structural formulas (104) to (107) was found to be greater than -0.085 E h It can be seen that the organic compounds represented by structural formulas (100) to (103) are organic compounds having electron-donating groups at the 4th and 7th positions of the 1,10-phenanthroline ring, and thus have the most preferable values.

[0132] Although the organic compound represented by structural formula (104) is an organic compound having electron-donating groups at the 4th and 7th positions of the 1,10-phenanthroline ring, an N-carbazolyl group is used as the electron-donating group. In the N-carbazolyl group, since the non-bonding electron pair of the nitrogen atom contributes to aromaticity, compared with a group in which the non-bonding electron pair of the nitrogen atom does not contribute to aromaticity, the electron-donating property to the phenanthroline ring decreases, so the minimum value of ESP does not easily decrease, resulting in such a result.

[0133]

[0134] The organic compounds represented by structural formulas (105) to (107) are organic compounds having electron-donating groups at the 2nd and 9th positions of the 1,10-phenanthroline ring. The electron-donating groups introduced at the 2nd and 9th positions have low electron-donating properties to the nitrogen atoms at the 1st and 10th positions of the phenanthroline ring. Therefore, the electron-donating groups on the 1,10-phenanthroline ring are preferably at the 4th and 7th positions.

[0135] ​Note that it is more preferable that the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound. Thereby, it is possible to facilitate electron donation from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Further, the second organic compound preferably has electron transporting properties, and for this reason too, it is preferable that the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound.

[0136] For example, it is preferable that the LUMO level of the first organic compound is -3.0 eV or more and -2.0 eV or less, and more preferably -2.7 eV or more and -2.0 eV or less. Further, for the second organic compound, it is preferable that the LUMO level is -3.0 eV or more and -2.0 eV or less, and more preferably -3.0 eV or more and -2.5 eV or less. Thereby, it is possible to facilitate electron donation from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Further, this makes the electron transport of the second organic compound easy.

[0137] Note that the HOMO level and LUMO level of an organic compound are generally estimated by methods such as CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values between different compounds, it is preferable to use values estimated by the same measurement for comparison.

[0138] Further, when the basicity of the first organic compound is high, by interacting with holes, it is possible to significantly reduce the hole transport property in the electron injection layer and prevent holes from being transported from the electron injection layer to the electron transport layer, so that it is possible to obtain an efficient light-emitting device, which is preferable. Specifically, it is preferable that the acid dissociation constant pKa is 8 or more, more preferably pKa is 10 or more, and even more preferably pKa is 12 or more.

[0139] When the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa for each skeleton of the organic compound can be determined, and the maximum acid dissociation constant pKa selected from them can be regarded as the acid dissociation constant pKa of the organic compound.

[0140] Alternatively, the acid dissociation constant may be determined by calculation. For example, the acid dissociation constant pKa can be determined using the following calculation method.

[0141] The initial structure of the molecular structure in each molecule serving as the calculation model shall be the most stable structure (singlet ground state) obtained from first-principles calculations.

[0142] As the above first-principles calculation, Jaguar, a quantum chemistry calculation software manufactured by Schrödinger, is used to calculate the most stable structure in the singlet ground state by the density functional theory (DFT). As the basis function, 6-31G** is used, and as the functional, B3LYP-D3 is used. The structure for which quantum chemistry calculation is to be performed is sampled by performing conformational analysis using the Mixed torsional / Low-mode sampling function of the Maestro GUI manufactured by Schrödinger.

[0143] In the pKa calculation, one or more atoms of each molecule are specified as basic sites, Macro Model is used to search for the stable structure of the protonated molecule in water, conformational search is performed using the OPLS2005 force field, and the conformer with the lowest energy is used. After optimizing the structure with B3LYP / 6-31G* using the pKa calculation module of Jaguar, a single-point calculation is performed with cc-pVTZ(+), and the pKa value is calculated using an empirical correction for the functional group. For a molecule in which one or more atoms are specified as basic sites, the largest value among the obtained results is adopted as the pKa value. The obtained pKa values are shown.

[0144] The acid dissociation constant pKa of 2,9hpp2Phen is 13.35, the acid dissociation constant pKa of 4,7hpp2Phen is 13.42, the acid dissociation constant pKa of Pyrrd-Phen is 11.23, the acid dissociation constant pKa of mPPhen2P is 5.16, the acid dissociation constant pKa of NBphen is 5.59, and the acid dissociation constant pKa of Bphen is 5.62.

[0145] <Second Organic Compound> In addition to the metal or metal oxide and the first organic compound, the electron injection layer has a second organic compound having two or more heteroaromatic rings bonded or condensed to each other, and the two or more heteroaromatic rings have a total of three or more heteroatoms. Further, the second organic compound has a function of interacting with a metal or a metal oxide in a multidentate manner by two or more of the three or more heteroatoms.

[0146] By having the second organic compound, it is possible to improve heat resistance, electron transportability, etc. In one aspect of the present invention, when the π-electron deficient heteroaromatic ring of the first organic compound is the first π-electron deficient heteroaromatic ring and the π-electron deficient heteroaromatic ring of the second organic compound is the second π-electron deficient heteroaromatic ring, the first π-electron deficient heteroaromatic ring and the second π-electron deficient heteroaromatic ring preferably contain different rings.

[0147] Further, as the second π-electron deficient heteroaromatic ring, a heteroaromatic ring having an azole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, and a heteroaromatic ring having a triazine skeleton are preferable, and in particular, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring is preferable because it is electrochemically stable and has high electron transportability.

[0148] For example, as the organic compound used for the second organic compound, an organic compound represented by the following general formula (G1-1) can be used.

[0149] [Chemical formula]

[0150] In the general formula (G1-1), A 1 , A 2 and A 3 each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, and A 1 , A 2 and A 3 may form a fused ring with each other.

[0151] The organic compound represented by the general formula (G1-1) has a conjugated double bond in which N on the heteroaromatic ring is arranged in the order of N-C-C-N, and has a function of interacting with a metal or metal oxide at three or more positions. Since an organic compound having such a structure easily interacts with a metal or metal oxide, it can be suitably used for an electron injection layer.

[0152] In the general formula (G1-1), examples of the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by A 1 , A 2 and A 3 include heteroaromatic rings having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, antiridine ring, azafluoranthene ring), heteroaromatic rings having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), heteroaromatic rings having a triazine skeleton, heteroaromatic rings having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. However, the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by A 1 , A 2 and A 3 is not limited to these. A 1 , A2 and A 3 may form a condensed ring with each other. For example, A 1 and A 2 may be bonded to each other to form a phenanthroline ring.

[0153] Further, as the organic compound used for the second organic compound, an organic compound represented by the following general formula (G2-1) can be used.

[0154]

Chemical formula

[0155] In the general formula (G2-1), X1 to X6 each independently represent carbon (C) or nitrogen (N). Carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms. R1 to R4 each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms. Alternatively, in the general formula (G2-1), X1 to X6 may be bonded to each other directly or via carbon to form a condensed ring.

[0156] It is more preferable that an organic compound having a function of interacting with a metal or a metal oxide at three or more positions, such as the organic compound represented by the general formula (G2-1), has at least one of a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, and a heteroaromatic ring having a triazine skeleton. Since these rings are excellent in electrochemical stability, a light-emitting device with good reliability can be provided. Further, since it is excellent in electron transport property, a light-emitting device with a reduced driving voltage can be provided.

[0157] In addition, as the organic compound used for the second organic compound, an organic compound represented by the following general formula (G3-1) can be used.

[0158]

Chem.

[0159] In general formula (G3-1), X1 to X4 each independently represent carbon (C) or nitrogen (N). Carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms. R1 to R6 each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms.

[0160] In addition, as the organic compound that can be used for the second organic compound, an organic compound represented by the following general formula (G4-1) can be used.

[0161]

Chem.

[0162] In general formula (G4-1), X1 to X5 each independently represent carbon (C) or nitrogen (N). Carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms. R1 to R5 each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms.

[0163] An organic compound having a pyridine skeleton is preferable because it has a high LUMO level. Therefore, when X1 and X2 represented by general formulas (G2-1) to (G4-1) represent carbon, since the organic compound has a pyridine skeleton, a composite material having a high SOMO level can be formed when it interacts with a metal or a metal oxide. That is, an organic compound having a pyridine ring and having a function of interacting at three or more sites can form an electron injection layer having high electron injectability by interacting with a metal or a metal oxide.

[0164] In addition, an organic compound having a diazine skeleton or a triazine skeleton is preferable because it is electrochemically stable and has high electron transport properties. Therefore, when at least one of X1 and X2 represented by general formulas (G2-1) to (G4-1) represents nitrogen, since the organic compound has a diazine skeleton or a triazine skeleton, a stable composite material having high electron transport properties can be formed when it interacts with a metal or a metal oxide. That is, an organic compound having a diazine ring or a triazine ring and having a function of interacting at three or more sites can form a reliable electron injection layer by interacting with a metal or a metal oxide.

[0165] In addition, for example, as the organic compound used for the second organic compound, an organic compound represented by the following general formula (G1-2) can be used.

[0166]

Chemical formula

[0167] In the above general formula (G1-2), A1 and A2 each independently represent a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, A1 and A2 may form a condensed ring with each other, and A1 has two or more nitrogen atoms.

[0168] The organic compound represented by the general formula (G1-2) has a conjugated double bond in which N on the heteroaromatic ring is arranged in the order of N-C-C-N, and has a function of interacting with a metal or metal oxide at two or more positions. Since the organic compound having such a structure easily interacts with a metal or metal oxide, it can be suitably used for an electron injection layer.

[0169] In the above general formula (G1-2), A 1 Examples of the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by include heteroaromatic rings having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), heteroaromatic rings having a triazine skeleton, heteroaromatic rings having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), and the like. Further, A 2 Examples of the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by include heteroaromatic rings having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, antiridine ring, azafluoranthene ring), heteroaromatic rings having a diazine skeleton (pyrazine ring, pyrimidine ring, pyridazine ring, quinoxaline ring, benzoquinoxaline ring, dibenzoquinoxaline ring, quinazoline ring, benzoquinazoline ring, phthalazine ring, cinnoline ring, pteridine ring, phenazine ring), heteroaromatic rings having a triazine skeleton, heteroaromatic rings having an azole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), and the like. However, the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by A 1 and A 2 is not limited to these. A 1 , and A 2 may form a condensed ring with each other. For example, A 1 and A 2They may be bonded to each other to form a pyrazinoquinoxaline ring.

[0170] In addition, as the organic compound used for the second organic compound, an organic compound represented by the following general formula (G2-2) can be used.

[0171]

Chemical formula

[0172] In the general formula (G2-2), at least one of X1 to X4 represents nitrogen (N), and the others each independently represent carbon (C) or nitrogen (N). Carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms. R1 to R4 each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 or more and 30 or less carbon atoms. Alternatively, in the general formula (G2-2), X1 to X4 may be bonded to each other directly or via carbon to form a condensed ring.

[0173] It is more preferable that an organic compound having a function of interacting with a metal or a metal oxide at two or more positions, such as the organic compound represented by the general formula (G2-2), has a heteroaromatic ring having a diazine skeleton or a heteroaromatic ring having a triazine skeleton. Since these rings are excellent in electrochemical stability, a light-emitting device with good reliability can be provided. In addition, since it is excellent in electron transport property, a light-emitting device with a reduced driving voltage can be provided.

[0174] In addition, as the organic compound used for the second organic compound, an organic compound represented by the following general formula (G3-2) can be used.

[0175] [Chemistry]

[0176] In general formula (G3-2), one of X1 or X2 represents nitrogen (N), and the other represents carbon (C) or nitrogen (N). Carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. R1 to R6 each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0177] Further, as the organic compound that can be used for the second organic compound, an organic compound represented by the following general formula (G4-2) can be used.

[0178] [Chemistry]

[0179] In general formula (G4-2), at least one of X1 to X3 represents nitrogen (N), and the others each independently represent carbon (C) or nitrogen (N). Carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms. R1 to R5 each independently represent hydrogen, an alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms.

[0180] Organic compounds having a pyridine skeleton are preferred because they have a high LUMO level. Therefore, when X1 and X2 represented by general formulas (G2-2) and (G4-2), and X1 represented by general formula (G3-2) represent carbon, since the organic compound has a pyridine skeleton, when interacting with a metal or metal oxide, a composite material having a high SOMO level can be formed. That is, an organic compound having a pyridine ring and having a function of interacting at two or more sites can form an electron injection layer having high electron injectability by interacting with a metal or metal oxide.

[0181] In addition, organic compounds having a diazine skeleton or a triazine skeleton are preferred because they are electrochemically stable and have high electron transport properties. Therefore, when at least one of X1 and X2 represented by general formulas (G2-2) and (G4-2), and X1 represented by general formula (G3-2) represents nitrogen, since the organic compound has a diazine skeleton or a triazine skeleton, when interacting with a metal or metal oxide, a stable composite material with high electron transport properties can be formed. That is, an organic compound having a diazine ring or a triazine ring and having a function of interacting at two or more sites can form a highly reliable electron injection layer by interacting with a metal or metal oxide.

[0182] Specific examples of the organic compounds used for the second organic compound and the organic compounds represented by the above general formulas (G1-1) to (G4-2) are shown below.

[0183]

Chemical formula

[0184]

Chemical formula

[0185] In addition, examples of substituents applicable in the above general formulas (G1-1) to (G4-2) include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group having 6 to 30 carbon atoms, an arylene group having 6 to 30 carbon atoms, and a heteroaryl group having 1 to 30 carbon atoms. Note that some or all of the hydrogens may be deuterium. Also, the groups applicable in the above general formula are not limited to the following specific examples.

[0186] Specific examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, a 2,3-dimethylbutyl group, a 1-ethylhexyl group, and the like.

[0187] Specific examples of the cycloalkyl group having 3 to 10 carbon atoms include a cyclopropyl group, a cyclobutyl group, a methylcyclobutyl group, a cyclopentyl group, a methylcyclopentyl group, an isopropylcyclopentyl group, a tert-butylcyclopropyl group, a cyclohexyl group, a methylcyclohexyl group, an isopropylcyclohexyl group, a tert-butylcyclohexyl group, a cycloheptyl group, a methylcycloheptyl group, an isopropylcycloheptyl group, a cyclooctyl group, a methylcyclooctyl group, an isopropylcyclohexyl group, a cyclononyl group, a methylcyclononyl group, a cyclodecyl group, an adamantyl group, and the like.

[0188] Specific examples of the aryl group having 6 to 30 carbon atoms include phenyl group, o-tolyl group, m-tolyl group, p-tolyl group, mesityl group, o-biphenyl group, m-biphenyl group, p-biphenyl group, 1-naphthyl group, 2-naphthyl group, fluorenyl group, 9,9-dimethylfluorenyl group, spirobifluorenyl group, phenanthrenyl group, anthracenyl group, fluoranthenyl group, etc. When the aryl group having 6 to 30 carbon atoms has a substituent, examples of the substituent include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, phenyl group, etc.

[0189] Specific examples of the arylene group having 6 to 30 carbon atoms include phenylene group, biphenyl-diyl group, naphthalene-diyl group, fluorene-diyl group, acenaphthene-diyl group, anthracene-diyl group, phenanthrene-diyl group, terphenyl-diyl group, triphenylene-diyl group, tetracene-diyl group, benzanthracene-diyl group, pyrene-diyl group, spirobi[9H-fluorene]-diyl group, etc. When the arylene group having 6 to 30 carbon atoms has a substituent, examples of the substituent include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, phenyl group, etc.

[0190] The heteroaryl group having 1 to 30 carbon atoms represents a monovalent group obtained by removing one hydrogen atom from one of the carbon atoms forming the ring of a monocyclic or polycyclic heteroaromatic compound having 1 to 30 carbon atoms. Specific examples of the heteroaryl group having 1 to 30 carbon atoms include a 1,3,5-triazin-2-yl group, a 1,2,4-triazin-3-yl group, a pyrimidin-4-yl group, a pyrazin-2-yl group, a 2-pyridyl group, a 3-pyridyl group, a 4-pyridyl group, a carbazolyl group, a dibenzofuranyl group, a dibenzothiophenyl group, a benzonaphthofuranyl group, a benzonaphthothiophenyl group, an indolocarbazolyl group, a benzofurocarbazolyl group, a benzothienocarbazolyl group, an indenocarbazolyl group, a dibenzocarbazolyl group, and the like. When the heteroaryl group has a substituent, examples of the substituent include an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a phenyl group, and the like.

[0191] Specific examples of the organic compound used for the second organic compound and the organic compounds represented by the above general formulas (G1-1) to (G4-2) are shown below.

[0192]

Chemical formula

[0193]

Chemical formula

[0194]

Chemical formula

[0195] Incidentally, it is more preferable that the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound. This makes it easier to donate electrons from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Also, the second organic compound preferably has electron transporting properties, and for this reason too, it is preferable that the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound.

[0196] The LUMO level of the second organic compound is preferably -3.2 eV or more and -2.0 eV or less, more preferably -3.1 eV or more and -2.0 eV or less, and even more preferably -3.0 eV or more and -2.5 eV or less. Also, the LUMO level of the first organic compound is preferably -3.0 eV or more and -2.0 eV or less, and more preferably -2.7 eV or more and -2.0 eV or less.

[0197] This makes it easier to donate electrons from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Also, this makes it easier for the second organic compound to transport electrons.

[0198] Also, in one aspect of the present invention, it is preferable that the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound and is a value that is 0.6 eV, preferably 0.50 eV, lower than the LUMO level of the first organic compound and is 0.20 eV or less lower than the LUMO level of the first organic compound, more preferably a value that is 0.50 eV or more lower than the LUMO level of the first organic compound and is 0.25 eV or less lower than the LUMO level of the first organic compound, even more preferably a value that is 0.50 eV or more lower than the LUMO level of the first organic compound and is 0.30 eV or less lower than the LUMO level of the first organic compound, even more preferably a value that is 0.50 eV or more lower than the LUMO level of the first organic compound and is 0.35 eV or less lower than the LUMO level of the first organic compound, and even more preferably a value that is 0.50 eV or more lower than the LUMO level of the first organic compound and is 0.40 eV or less lower than the LUMO level of the first organic compound.

[0199] That is, assuming that the LUMO level of the first organic compound is "LUMO1 (eV)" and the LUMO level of the second organic compound is "LUMO2 (eV)", it is preferable that LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.20

[0200] More preferably, it is preferable that LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.25

[0201] More preferably, it is preferable that LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.30

[0202] More preferably, it is preferable that LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.35

[0203] More preferably, it is preferable that LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.40

[0204] When LUMO2 is within the above range, the light-emitting device according to one embodiment of the present invention can be a light-emitting device having good characteristics with a low driving voltage, whether or not it undergoes a photolithography process involving exposure of the EL layer to the atmosphere. Further, a light-emitting device with good reliability can be obtained.

[0205] As the second organic compound, an organic compound having electron transporting properties can be used. As the organic compound having electron transporting properties, the electron mobility at a square root of the electric field strength [V / cm] of 600 is 1×10 -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2A substance having an electron mobility of 1 / Vs or more is preferable. In addition, other substances can be used as long as they have higher electron transportability than holes.

[0206] In addition, the number of carbon atoms of the second organic compound is preferably 25 or more and 100 or less. By setting the number of carbon atoms in this way, an organic compound excellent in sublimability can be obtained, so that thermal decomposition of the organic compound can be suppressed in vacuum deposition, and good material use efficiency can be obtained.

[0207] In addition, as the second organic compound, an organic compound having a glass transition temperature T g of 100°C or higher is preferably used. Thereby, the electron injection layer can be made into a layer with good heat resistance and difficult to crystallize. Therefore, even when a part of the organic compound layer is processed by a lithography method, it can be made into a layer difficult to crystallize.

[0208] In addition, as the second organic compound, an organic compound having an acid dissociation constant pKa of less than 4 can be used. By doing so, the solubility of the second organic compound in water can be made poor, so that the resistance to water and chemical solutions used in the process in the lithography method can be enhanced.

[0209] Compared with the solubility in water of an organic compound having an acid dissociation constant pKa of 4 or more, the solubility in water of an organic compound having an acid dissociation constant pKa of less than 4 is low. In addition, compared with the case where an organic compound having an acid dissociation constant pKa of 4 or more is used as the second organic compound, when an organic compound having an acid dissociation constant pKa of less than 4 is used as the second organic compound, the water resistance of the electron injection layer can be improved. In addition, in the manufacturing process, the occurrence of problems such as the electron injection layer peeling off from other layers can be suppressed. Thereby, the occurrence of problems that cause defects in the light-emitting device can be suppressed.

[0210] In addition, when the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa can be determined for each skeleton of the organic compound, and the maximum acid dissociation constant pKa selected therefrom can be regarded as the acid dissociation constant pKa of the organic compound.

[0211] In addition, in the first layer, by including a second organic compound in addition to the metal or metal oxide and the first organic compound, the interaction between the materials occurs efficiently. This can be confirmed by measuring the spin density by electron spin resonance (ESR).

[0212] For example, it is preferable that the spin density measured by ESR of a film containing a metal or metal oxide and the first organic compound is higher than the spin density measured by ESR of a film containing a metal or metal oxide and the second organic compound. Also, it is preferable that the spin density measured by ESR of a film containing a metal or metal oxide, the first organic compound, and the second organic compound is higher compared to the spin density measured by ESR of a film having only any two of the materials of a metal or metal oxide, the first organic compound, and the second organic compound. In that case, it can be confirmed that the interaction between the materials occurs efficiently.

[0213] More specifically, in a film containing a metal or metal oxide and the first organic compound, for example, the spin density caused by the signal observed around a g value of 2.00 by electron spin resonance method is 5×10 16 spins / cm 3 or more, more preferably 1×10 17 spins / cm 3 or more, more preferably 1×10 18 spins / cm 3 or more, more preferably 1×10 19 spins / cm 3 or more, more preferably 1×10 20 spins / cm 3The above is preferable. In such a case, in the layer having a combination of a metal or metal oxide and a first organic compound, it can be confirmed that the interaction between the materials occurs efficiently. Or, in the film containing a metal or metal oxide, a first organic compound, and a second organic compound, for example, by electron spin resonance method, the spin density due to the signal observed around a g-value of 2.00 is 5×10 16 spins / cm 3 or more, more preferably 1×10 17 spins / cm 3 or more, more preferably 1×10 18 spins / cm 3 or more, more preferably 1×10 19 spins / cm 3 or more, more preferably 1×10 20 spins / cm 3 or more is preferable. In such a case, in the layer having a combination of a metal or metal oxide, a first organic compound, and a second organic compound, it can be confirmed that the interaction between the materials occurs more efficiently compared to the layer having only two of these materials. At this time, for the mixed film containing a metal or metal oxide and a second organic compound, for example, by electron spin resonance method, the spin density due to the signal observed around a g-value of 2.00 is 2×10 16 spins / cm 3 or less, and for the mixed film containing a first organic compound and a second organic compound, for example, by electron spin resonance method, the spin density due to the signal observed around a g-value of 2.00 is 2×10 16 spins / cm 3 or less.

[0214] In the first layer, the metal or metal oxide preferably has a molar ratio of 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and even more preferably 0.5 or more and 2 or less, based on the first organic compound (or the total of the first organic compound and the second organic compound). Alternatively, in terms of volume ratio, it is preferably 0.01 or more and 0.3 or less, more preferably 0.02 or more and 0.2 or less, and even more preferably 0.05 or more and 0.1 or less. By having the first layer containing the metal or metal oxide and the first organic compound (or the first organic compound and the second organic compound) in such a ratio, an electron injection layer having good electron injection properties can be provided. Also, the second organic compound may not be used, but when the second organic compound is used, the ratio of the first organic compound is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and even more preferably 0.5 or more and 2 or less, in terms of volume ratio with respect to the second organic compound. By mixing the first organic compound and the second organic compound in such a ratio, an electron injection layer having good electron transport properties can be provided. Also, by using an organic compound with high T g and good thermal properties, it becomes possible to provide an organic EL device with good reliability.

[0215] Also, the film thickness of the first layer is preferably 2 nm or more and 20 nm or less, and more preferably 5 nm or more and 10 nm or less. When the first layer has a laminated structure of a layer of a metal or metal oxide and a layer containing the first organic compound, the layer of the metal or metal oxide is preferably 0.1 nm or more and 5 nm or less, and more preferably 0.2 nm or more and 2 nm or less. Also, when the first layer has a laminated structure of a layer of a metal or metal oxide and a layer containing the first organic compound, the film thickness of the layer containing the first organic compound is preferably 2 nm or more and 20 nm or less, and more preferably 5 nm or more and 10 nm or less.

[0216] By using the second organic compound described above, it is possible to make it function well as a composite material in which the metal or metal oxide, the first organic compound, and the second organic compound are mixed, and to provide a light-emitting device showing high luminous efficiency.

[0217] (Embodiment 2) In this embodiment, a light-emitting device according to an aspect of the present invention will be described in detail.

[0218] FIG. 1(A) is a schematic diagram of a light-emitting device according to an aspect of the present invention. The light-emitting device has a first electrode 101 provided on an insulator 109, and has an organic compound layer 103 between the first electrode 101 and a second electrode 102. The organic compound layer 103 has at least a light-emitting layer 113 and an electron injection layer 115. The light-emitting layer 113 is a layer containing a light-emitting substance, and emits light by applying a voltage between the first electrode 101 and the second electrode 102.

[0219] In addition to the light-emitting layer 113 and the electron injection layer 115, the organic compound layer 103 preferably has functional layers such as a hole injection layer 111, a hole transport layer 112, and an electron transport layer 114 as shown in FIG. 1(A). The organic compound layer 103 may include functional layers other than the above-described functional layers, such as a hole blocking layer, an exciton blocking layer, and an intermediate layer. Conversely, any of the above-described layers may not be provided.

[0220] Further, the electron injection layer 115 is a layer containing a metal or metal oxide, an organic compound having a first π-electron deficient heteroaromatic ring having an electron donating group (first organic compound), and an organic compound having a second π-electron deficient heteroaromatic ring (second organic compound) as described in Embodiment 1. The electron injection layer 115 may further have another organic compound (third organic compound).

[0221] The specific configuration of the electron injection layer 115 has been described in detail in Embodiment 1, and redundant description will be omitted.

[0222] In addition, in this embodiment, the first electrode 101 is an electrode including an anode, and the second electrode 102 is an electrode including a cathode. Although an example in which the first electrode 101 is formed on the insulator 109 side has been shown, a so-called reverse stacking configuration in which the second electrode 102 is formed on the insulator 109 side may also be used. At this time, the light-emitting device has a stacked structure in the order of the second electrode 102, the electron injection layer 115, (the electron transport layer 114), the light-emitting layer 113, (the hole transport layer 112, the hole injection layer 111,), and the first electrode 101 from the insulator 109 side. In the case of such a light-emitting device having a reverse stacking structure, since the relatively stable hole injection layer 111 is on the surface, a more reliable light-emitting device can be obtained.

[0223] Further, the first electrode 101 and the second electrode 102 may be formed as a single-layer structure or a stacked structure. When having a stacked structure, the layer in contact with the organic compound layer 103 functions as an anode or a cathode. When the electrode has a stacked structure, there are no restrictions on the work function for the layers other than the layer in contact with the organic compound layer 103, and the material may be selected according to the required characteristics such as the resistance value, processability, reflectance, transmittance, and stability.

[0224] The anode is preferably formed using a metal, alloy, conductive compound, or a mixture thereof with a large work function (specifically, 4.0 eV or more). Specifically, for example, indium tin oxide (ITO), indium tin silicon oxide containing silicon or silicon oxide (ITSO), indium zinc oxide, indium tungsten zinc oxide (IWZO) containing tungsten oxide and zinc oxide, etc. can be mentioned. These conductive metal oxide films are usually formed by sputtering, but may also be produced by applying a sol-gel method or the like. As an example of the production method, indium zinc oxide can be formed by sputtering using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. Also, indium tungsten zinc oxide (IWZO) containing tungsten oxide and zinc oxide can also be formed by sputtering using a target containing 0.5 to 5 wt% of tungsten oxide and 0.1 to 1 wt% of zinc oxide with respect to indium oxide. In addition, materials used for the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), or nitrides of metal materials (for example, titanium nitride), etc. Also, a layer formed by laminating these may be used as the anode. For example, a film laminated in the order of Al, Ti, ITSO on Ti is preferable because it has good reflectivity, is highly efficient, and enables high definition of several thousand ppi. Alternatively, graphene can also be used as the material for the anode. In addition, by using a composite material capable of forming the hole injection layer 111 described later as a layer in contact with the anode (typically the hole injection layer), the electrode material can be selected regardless of the work function.

[0225] The positive hole injection layer 111 is provided in contact with the anode and has a function of facilitating the injection of positive holes into the organic compound layer 103. The positive hole injection layer 111 can be formed of phthalocyanine-based compounds or complex compounds such as phthalocyanine (abbreviation: H2Pc), copper phthalocyanine (abbreviation: CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviation: PEDOT / PSS).

[0226] In addition, the hole injection layer 111 may be formed of a substance having electron acceptor properties. As the substance having electron acceptor properties, organic compounds having an electron-withdrawing group (such as a halogen group or a cyano group) can be used. Examples thereof include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene) malononitrile, and the like. In particular, a compound in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms, such as HAT-CN, is thermally stable and preferable. Further, [3]radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) are preferable because of their very high electron accepting properties. Specifically, α,α’,α’’-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α’,α’’-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], and the like can be mentioned. As the substance having electron acceptor properties, in addition to the organic compounds described above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used.

[0227] In addition, the hole injection layer 111 is preferably formed of a composite material containing the above-described material having electron acceptor properties and an organic compound having hole transporting properties.

[0228] As the organic compound having hole transporting properties used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as the organic compound having hole transporting properties used in the composite material, it is preferably an organic compound having a hole mobility of 1×10 -6 cm 2 / Vs or more. The organic compound having hole transporting properties used in the composite material is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron excess type heteroaromatic ring. As the condensed aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferable. Further, as the π-electron excess type heteroaromatic ring, a condensed aromatic ring containing at least any one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton in the ring is preferable, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed thereto is preferable.

[0229] In addition, in the composite material containing the material having the electron accepting property and the organic compound having hole transporting properties, the interaction between the materials occurs efficiently. Therefore, the spin density measured by the electron spin resonance method (ESR: Electron spin resonance) of the film containing the composite material is such that the spin density caused by the signal observed near the g value of 2.00 is 1×10 17 spins / cm 3 or more is preferable.

[0230] As such an organic compound having hole transporting properties, it is more preferable to have any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group may be used. Note that when these organic compounds having hole transporting properties are substances having an N,N-bis(4-biphenyl)amino group, it is preferable because a light emitting device having a good lifetime can be fabricated.

[0231] Examples of the organic compound having hole transporting properties as described above include specifically 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 (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-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: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (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'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-1-amine and the like can be mentioned.,

[0232] In addition, as materials having hole-transporting properties, among other aromatic amine compounds, N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc. can be used.

[0233] By forming the hole injection layer 111, the injectability of holes becomes good, and a light-emitting device with a small driving voltage can be obtained.

[0234] Among substances having electron-accepting properties, organic compounds having an accepting property are easy to vapor-deposit and easy to form a film, so they are easy-to-use materials.

[0235] The hole transport layer 112 is formed by including an organic compound having hole-transporting properties. As the organic compound having hole-transporting properties, it preferably has a hole mobility of 1×10 -6 cm 2 / Vs or more.

[0236] Examples of the material having hole transporting properties include compounds having an aromatic amine skeleton such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)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]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF); compounds such as 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), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-Bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1''-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylene-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylene-2-yl)-9'-[1,1':3',1''-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, and other compounds having a carbazole skeleton, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), etc., and compounds having a furan skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), etc. Among the above-mentioned, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to the reduction of driving voltage. In addition, the substances listed as hole-transporting materials used in the composite material of the hole injection layer 111 can also be preferably used as the materials constituting the hole transport layer 112.,

[0237] The light-emitting layer 113 is a layer having a light-emitting substance, and preferably has a light-emitting substance and a host material. Note that the light-emitting layer may simultaneously contain other materials. Also, it may be a laminate of two layers having different compositions.

[0238] The light-emitting substance may be a fluorescent light-emitting substance, a phosphorescent light-emitting substance, a substance showing thermally activated delayed fluorescence (TADF), or other light-emitting substances.

[0239] In the light-emitting layer, examples of materials that can be used as fluorescent light-emitting substances include the following. Also, other fluorescent light-emitting substances can also be used.

[0240] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyl-di-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N''' -octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(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(biphenyl-2-yl)-2-anthryl]-N,N’,N’-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N’-diphenylquinacridone (abbreviation: DPQd), Rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N’,N’-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N’,N’-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-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: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N’-diphenyl-N,N’-(1,6-pyrenediyl)bis[(6-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), N,N’-diphenyl-N,N’-bis(9-phenyl-9H-carbazol-2-yl)naphtho[2,3-b;6,7-b’]bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b’]bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. are mentioned. In particular, condensed aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn and 1,6mMemFLPAPrn, 1,6BnfAPrn-03 are preferable because they have high hole trapping properties and are excellent in luminous efficiency or reliability.,

[0241] Also, 5,9-diphenyl-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracene (abbreviation: DABNA1), 9-[(1,1'-diphenyl)-3-yl]-N,N,5,11-tetraphenyl-5,9-dihydro-5,9-diaza-13b-boranaphtho[3,2,1-de]anthracen-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: Me-tBu4DABNA), N 7 ,N 7 ,N 13 ,N 13 ,5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4’,3’,2’:4,5][1,4]benzazaborino[3,2-b]phenazaborine-7,13-diamine (abbreviation: ν-DABNA), 2-(4-tert-butylphenyl)benzo[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc) and other condensed heteroaromatic compounds containing nitrogen and boron, especially compounds having a diaza-boranaphtho-anthracene skeleton, can be suitably used because they can obtain blue light emission with a narrow emission spectrum width and good color purity.

[0242] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3’,2’,1’:8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazol-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3’,2’,1’:8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-Y), etc. can be preferably used.

[0243] When a phosphorescent light-emitting material is used as the light-emitting material in the light-emitting layer, examples of the materials that can be used include the following.

[0244] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), organometallic iridium complexes having a 4H-triazole skeleton such as tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), organometallic iridium complexes having a 1H-triazole skeleton such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), organometallic iridium complexes having an imidazole skeleton such as tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN3}-4-cyanophenyl-κC) (abbreviation: CNImIr), organometallic complexes having a benzimidazolylidene skeleton such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4’,6’-difluorophenyl)pyridinato-N,C 2’ iridium(III) 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’ Organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group such as iridium(III) acetylacetonate (abbreviation: FIracac) as a ligand can be mentioned. These are compounds that exhibit blue phosphorescent emission and have an emission peak in the wavelength range from 450 nm to 520 nm.

[0245] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]) and other organometallic iridium complexes having a pyrimidine skeleton, (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]) and other organometallic iridium complexes having a pyrazine skeleton, tris(2-phenylpyridinato-N,C 2’) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (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(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mdppy)]), in addition to organometallic iridium complexes having a pyridine skeleton, rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). These are mainly compounds that exhibit green phosphorescent emission and have an emission peak in the wavelength range from 500 nm to 600 nm. In addition, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are also remarkably excellent in reliability or luminescence efficiency.

[0246] Also, organometallic iridium complexes having a pyrimidine skeleton such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), organometallic iridium complexes having a pyrazine skeleton such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ )iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’In addition to organometallic iridium complexes having a pyridine skeleton such as iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), and (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III), platinum complexes such as platinum(II) 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin (abbreviation: PtOEP), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]) can be mentioned. These are compounds that exhibit red phosphorescent emission and have an emission peak in the wavelength range from 600 nm to 700 nm. In addition, organometallic iridium complexes having a pyrazine skeleton can obtain red emission with good chromaticity.

[0247] In addition to the phosphorescent compounds described above, known phosphorescent compounds may be selected and used.

[0248] As the TADF material, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc. can be used. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc. can be mentioned. Examples of the metal-containing porphyrins include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc. shown by the following structural formulas.

[0249] [Chemical formula]

[0250] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-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'-anthracene]-10'-one (abbreviation: ACRSA), and other heterocyclic compounds having one or both of a π-electron-excessive heterocyclic aromatic ring and a π-electron-deficient heterocyclic aromatic ring can also be used. Since the heterocyclic compound has a π-electron-excessive heterocyclic aromatic ring and a π-electron-deficient heterocyclic aromatic ring, it has both high electron transportability and hole transportability, which is preferable. Among them, among the skeletons having a π-electron-deficient heterocyclic aromatic ring, a pyridine skeleton, a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and a triazine skeleton are preferable because they are stable and have good reliability. In particular, a benzofuropyrimidine skeleton, a benzothienopyrimidine skeleton, a benzofuropyrazine skeleton, and a benzothienopyrazine skeleton are preferable because they have high electron acceptor properties and good reliability. Also, among the skeletons having a π-electron-excessive heterocyclic aromatic ring, an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton are stable and have good reliability, so it is preferable to have at least one of these skeletons.Note that as the furan skeleton, a dibenzofuran skeleton is preferable, and as the thiophene skeleton, a dibenzothiophene skeleton is preferable. Further, as the pyrrole skeleton, an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton are particularly preferable. Note that a substance in which a π-electron-excessive heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded has both the strong electron-donating property of the π-electron-excessive heteroaromatic ring and the strong electron-accepting property of the π-electron-deficient heteroaromatic ring, and the energy difference between the S1 level and the T1 level becomes small. Therefore, it is particularly preferable because thermally activated delayed fluorescence can be efficiently obtained. Note that instead of the π-electron-deficient heteroaromatic ring, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used. Further, as the π-electron-excessive skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. can be used. Further, as the π-electron-deficient skeleton, a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane and borantrene, an aromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. can be used. Thus, a π-electron-deficient skeleton and a π-electron-excessive skeleton can be used instead of at least one of the π-electron-deficient heteroaromatic ring and the π-electron-excessive heteroaromatic ring.

[0251]

Chemical Structure

[0252] Note that a TADF material is a material having a function in which the difference between the S1 level and the T1 level is small and energy can be converted from triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, upconversion (reverse intersystem crossing) of triplet excitation energy to singlet excitation energy is possible with a small amount of thermal energy, and a singlet excited state can be efficiently generated. Further, triplet excitation energy can be converted into light emission.

[0253] In addition, an exciplex (also referred to as an exciplex, exciplex, or exciplex) that forms an excited state with two types of substances has a very small difference between the S1 level and the T1 level and has a function as a TADF material capable of converting triplet excitation energy into singlet excitation energy.

[0254] Note that as an index of the T1 level, a phosphorescence spectrum observed at a low temperature (for example, from 77K to 10K) may be used. As a TADF material, a tangent is drawn at the short-wavelength side skirt of its fluorescence spectrum, and the energy of the wavelength of the extrapolated line is taken as the S1 level. A tangent is drawn at the short-wavelength side skirt of the phosphorescence spectrum, and the energy of the wavelength of the extrapolated line is taken as the T1 level. When the difference between S1 and T1 is 0.3 eV or less, preferably 0.2 eV or less.

[0255] When using a TADF material as a light-emitting substance, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0256] As the host material of the light-emitting layer, various carrier transport materials such as a material having electron transport properties and / or a material having hole transport properties, and the above TADF material can be used.

[0257] As the material having hole transport properties, an organic compound having an amine skeleton, a π-electron excess type heteroaromatic ring skeleton, etc. is preferable. As the π-electron excess type heteroaromatic ring, a condensed aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton in the ring is preferable. Specifically, a carbazole ring, a dibenzothiophene ring, or a ring further condensed with an aromatic ring or a heteroaromatic ring is preferable.

[0258] As such an organic compound having hole transporting properties, it is more preferable to have any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. In addition, it is preferable that these organic compounds having hole transporting properties are substances having an N,N-bis(4-biphenyl)amino group because a light-emitting device with good lifespan can be fabricated.

[0259] Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)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]fluorene-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), and other compounds having an aromatic amine skeleton, 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), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), and other compounds having a carbazole skeleton, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), compounds having a furan skeleton such as 4,4’,4’’-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), etc. Among the above-mentioned, compounds having an aromatic amine skeleton or a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Also, the organic compounds exemplified as materials having hole transportability in the hole transport layer can also be used.,

[0260] Examples of the material having electron transportability include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), etc., and organic compounds having a π-electron-deficient heteroaromatic ring are preferable. Examples of the organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring having an azole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0261] Among them, an organic compound containing a heteroaromatic ring having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) or an organic compound containing a heteroaromatic ring having a pyridine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton are preferable because of their good reliability. In particular, an organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. In addition, a benzofuropyrimidine skeleton, a benzothienopyrimidine skeleton, a benzofuropyrazine skeleton, and a benzothienopyrazine skeleton are preferable because they have high electron acceptor properties and good reliability.

[0262] Examples of organic compounds having a π-electron deficient heteroaromatic ring skeleton include, for example, 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2’,2’’-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), organic compounds having an azole skeleton such as 4,4’-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2’-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: PnNPhen), 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), etc. organic compounds containing a heteroaromatic ring having a pyridine skeleton, 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]Quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3’-(Dibenzothiophen-4-yl)biphenyl-3-yl]dibenzof[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3’-(9H-Carbazol-9-yl)biphenyl-3-yl]dibenzof[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-{3-[3-(N-Phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzof[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), 2-[4’-(9-Phenyl-9H-carbazol-3-yl)-3,1’-biphenyl-1-yl]dibenzof[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenzof[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(Dibenzothiophen-4-yl)phenyl]dibenzof[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(Dibenzothiophen-4-yl)phenyl]dibenzof[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3’-(Dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3’-(Dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1’,2’:4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-Bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-Bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-Bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9’-[Pyrimidine-4,6-diylbis(biphenyl-3,3’-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(Biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-Bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-Bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3’-(Dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1’,2’:4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2’-Binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2’-(Pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2’-(Pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(Biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-Bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz) and other organic compounds having a diazine skeleton, 2-(Biphenyl-4-yl)-4-phenyl-6-(9,9’-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(Benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(Benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5 - Triazine (abbreviation: mBnfBPTzn - 02), 2 - {4 - [3 - (N - phenyl - 9H - carbazol - 3 - yl) - 9H - carbazol - 9 - yl]phenyl}-4,6 - diphenyl - 1,3,5 - triazine (abbreviation: PCCzPTzn), 9 - [3 - (4,6 - diphenyl - 1,3,5 - triazine - 2 - yl)phenyl]-9’ - phenyl - 2,3’ - bi - 9H - carbazole (abbreviation: mPCCzPTzn - 02), 2 - [3’ - (9,9 - dimethyl - 9H - fluorene - 2 - yl)biphenyl - 3 - yl]-4,6 - diphenyl - 1,3,5 - triazine (abbreviation: mFBPTzn), 5 - [3 - (4,6 - diphenyl - 1,3,5 - triazine - 2 - yl)phenyl]-7,7 - dimethyl - 5H,7H - indeno[2,1 - b]carbazole (abbreviation: mINc(II)PTzn), 2 - {3 - [3 - (dibenzothiophen - 4 - yl)phenyl]phenyl}-4,6 - diphenyl - 1,3,5 - triazine (abbreviation: mDBtBPTzn), 2,4,6 - tris[3’ - (pyridin - 3 - yl)biphenyl - 3 - yl]-1,3,5 - triazine (abbreviation: TmPPPyTz), 2 - [3 - (2,6 - dimethyl - 3 - pyridinyl)-5 - (9 - phenanthrenyl)phenyl]-4,6 - diphenyl - 1,3,5 - triazine (abbreviation: mPn - mDMePyPTzn), 11 - [4 - (biphenyl - 4 - yl)-6 - phenyl - 1,3,5 - triazine - 2 - yl]-11,12 - dihydro - 12 - phenyl - indolo[2,3 - a]carbazole (abbreviation: BP - Icz(II)Tzn), 2 - [3’ - (triphenylene - 2 - yl)biphenyl - 3 - yl]-4,6 - diphenyl - 1,3,5 - triazine (abbreviation: mTpBPTzn), 3 - [9 - (4,6 - diphenyl - 1,3,5 - triazine - 2 - yl)-2 - dibenzofuranyl]-9 - phenyl - 9H - carbazole (abbreviation: PCDBfTzn), 2 - (biphenyl - 3 - yl)-4 - phenyl - 6 - {8 - [(1,1’:4’,1’’ - terphenyl)-4 - yl]-1 - dibenzofuranyl}-1,3,5 - triazine (abbreviation: mBP - TPDBfTzn), 2 - [4 - (2 - naphthalenyl)phenyl]-4 - phenyl - 6 - spiro[9H - fluorene - 9,9’ - [9H]xanthene]-4 - yl - 1,3,Examples of the organic compound containing a heteroaromatic ring having a triazine skeleton include 5-triazine (abbreviation: βNP-SFx(4)Tzn), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), etc. Further, an organic compound containing a heteroaromatic ring having a diazine skeleton or an organic compound containing a heteroaromatic ring having a pyridine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton are preferable because of their good reliability. In particular, an organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage.,

[0263] As the TADF material that can be used as the host material, those previously listed as the TADF material can be used in the same manner. When the TADF material is used as the host material, the triplet excitation energy generated in the TADF material is converted into singlet excitation energy by reverse intersystem crossing, and further, by transferring the energy to the luminescent material, the luminous efficiency of the light-emitting device can be increased. At this time, the TADF material functions as an energy donor, and the luminescent material functions as an energy acceptor.

[0264] This is very effective when the above luminescent material is a fluorescent luminescent material. Further, at this time, in order to obtain a high luminous efficiency, it is preferable that the S1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Also, it is preferable that the T1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than the T1 level of the fluorescent luminescent material.

[0265] Further, it is preferable to use a TADF material that exhibits light emission overlapping with the wavelength of the absorption band on the lowest energy side of the fluorescent luminescent material. By doing so, the transfer of excitation energy from the TADF material to the fluorescent luminescent material becomes smooth, and light emission can be obtained efficiently, which is preferable.

[0266] In addition, in order for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. Further, it is preferable that the triplet excitation energy generated in the TADF material does not move to the triplet excitation energy of the fluorescent substance. For this purpose, it is preferable that the fluorescent substance has a protecting group around the luminophore (the skeleton responsible for luminescence) that the fluorescent substance has. As the protecting group, a substituent having no π bond is preferable, a saturated hydrocarbon is preferable, and specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms can be mentioned. It is more preferable that there are a plurality of protecting groups. Since a substituent having no π bond has a poor function of transporting carriers, it is possible to increase the distance between the TADF material and the luminophore of the fluorescent substance with little influence on carrier transport or carrier recombination. Here, the luminophore refers to an atomic group (skeleton) that causes luminescence in the fluorescent substance. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such luminophores include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferable because they have a high fluorescence quantum yield.

[0267] When using a fluorescent light-emitting substance as the light-emitting substance, as the host material, a material having an anthracene skeleton is suitable. When a substance having an anthracene skeleton is used as the host material of the fluorescent light-emitting substance, it is possible to realize a light-emitting layer with both good luminous efficiency and durability. As the substance having an anthracene skeleton used as the host material, a substance having a diphenylanthracene skeleton, particularly a substance having a 9,10-diphenylanthracene skeleton, is preferable because it is chemically stable. Further, when the host material has a carbazole skeleton, it is preferable because the hole injection / transport property is enhanced. However, when it contains a benzocarbazole skeleton in which a benzene ring is further condensed with carbazole, the HOMO level becomes about 0.1 eV shallower than when it contains a carbazole skeleton, and holes can enter more easily, so it is more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, the HOMO level becomes about 0.1 eV shallower than when it contains a carbazole skeleton, holes can enter more easily, the hole transport property is excellent, and the heat resistance is also high, so it is suitable. Therefore, as the host material, a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton) is more preferable. From the above viewpoint of hole injection / transport property, instead of the carbazole skeleton, a benzofluorene skeleton or a dibenzofluorene skeleton may be used.Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl]anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), and the like. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good properties and are thus preferred choices.

[0268] Note that the host material may be a material obtained by mixing multiple substances. When using a mixed host material, it is preferable to mix a material having electron-transporting properties and a material having hole-transporting properties. By mixing a material having electron-transporting properties and a material having hole-transporting properties, the transport properties of the light-emitting layer 113 can be easily adjusted, and the control of the recombination region can also be easily performed. The weight ratio of the content of the material having hole-transporting properties to the material having electron-transporting properties may be Hole-transporting material: Electron-transporting material = 1:19 to 19:1.

[0269] In addition, a phosphorescent substance can be used as part of the above mixed materials. The phosphorescent substance can be used as an energy donor that supplies excitation energy to the fluorescent substance when the fluorescent substance is used as the luminescent substance.

[0270] Also, an exciplex may be formed between these mixed materials. By selecting a combination that forms an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the luminescent substance, energy transfer becomes smooth and light emission can be obtained efficiently, which is preferable. In addition, using this configuration is preferable because the driving voltage is also reduced.

[0271] Note that at least one of the materials forming the exciplex may be a phosphorescent substance. By doing so, triplet excitation energy can be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0272] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transport properties is higher than the HOMO level of the material having electron transport properties. Also, it is preferable that the LUMO level of the material having hole transport properties is higher than the LUMO level of the material having electron transport properties. Note that the LUMO level and HOMO level of the material can be derived from the electrochemical characteristics (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0273] Note that the formation of an exciplex can be confirmed, for example, by comparing the emission spectra of a material having hole-transporting properties, the emission spectrum of a material having electron-transporting properties, and the emission spectrum of a mixed film in which these materials are mixed, and observing the phenomenon that the emission spectrum of the mixed film is shifted to a longer wavelength (or has a new peak on the longer wavelength side) than the emission spectra of the respective materials. Alternatively, the transient photoluminescence (PL) of a material having hole-transporting properties, the transient PL of a material having electron-transporting properties, and the transient PL of a mixed film in which these materials are mixed are compared, and the difference in transient response such that the transient PL lifetime of the mixed film has a longer lifetime component or the ratio of the delayed component becomes larger than the transient PL lifetimes of the respective materials is observed to confirm. Further, the above transient PL may be read as transient electroluminescence (EL). That is, the transient EL of a material having hole-transporting properties, the transient EL of a material having electron-transporting properties, and the transient EL of a mixed film thereof are compared, and the formation of an exciplex can also be confirmed by observing the difference in transient response.

[0274] The electron transport layer 114 is a layer containing a substance having electron-transporting properties. As the material having electron-transporting properties, a substance having an electron mobility with the square root of the electric field strength [V / cm] at 600 being 1×10 -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 / Vs or more is preferred. Note that any other substance can be used as long as it has higher electron-transporting properties than holes. As the above organic compound, an organic compound having a π-electron deficient heteroaromatic ring is preferred. As the organic compound having a π-electron deficient heteroaromatic ring, for example, it is preferably any one or more of an organic compound containing a heteroaromatic ring having an azole skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, an organic compound containing a heteroaromatic ring having a diazine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton.

[0275] As the organic compound having electron transporting properties that can be used for the above-mentioned electron transport layer 114, the organic compounds having electron transporting properties in the above-mentioned light emitting layer 113 and the organic compounds that can be used as the second organic compound of the electron injection layer 115 in Embodiment 1 can be used in the same manner. Among them, an organic compound containing a heteroaromatic ring having a diazine skeleton or a heteroaromatic ring having a pyridine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton are preferable because of their good reliability. In particular, an organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transporting properties and contribute to reducing the driving voltage. Organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen, and mPPhen2P are preferable, and organic compounds having a phenanthroline dimer structure such as mPPhen2P are more preferable because of their excellent stability. In addition, it is preferable to use an organic compound having electron transporting properties and a high HOMO level such as 2mPCCzPDBq and DACT-II, because a light emitting device with a low driving voltage can be obtained.

[0276] In addition, the electron transport layer preferably contains an organic compound having electron transporting properties and an acid dissociation constant pKa of less than 4.

[0277] Note that the electron transport layer 114 may have a laminated structure. When the electron transport layer 114 has a laminated structure, the layer in contact with the light emitting layer 113 may function as a hole blocking layer. When the electron transport layer in contact with the light emitting layer functions as a hole blocking layer, it is preferable to use a material whose HOMO level is 0.5 eV or more deeper than the HOMO level of the material contained in the light emitting layer.

[0278] An electron injection layer 115 is formed between the electron transport layer 114 and the second electrode 102. Since the configuration of the electron injection layer 115 has been described in detail in Embodiment 1, repeated explanations are omitted.

[0279] The second electrode 102 is an electrode including a cathode. The second electrode 102 may have a laminated structure, and in that case, the layer in contact with the organic compound layer 103 functions as a cathode. As the material for forming the cathode, a metal, alloy, electrically conductive compound, or a mixture thereof having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), strontium (Sr), and alloys (MgAg, AlLi), compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), etc.) containing these, rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer 115 or a thin film of a material having a small work function as described above between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, indium tin oxide containing silicon or silicon oxide, etc. can be used as the cathode regardless of the magnitude of the work function.

[0280] In addition, when the second electrode 102 is formed of a material having visible light transmissibility, the first electrode 101 is formed of a material having visible light transmissibility from the second electrode 102 side, or the first electrode 101 is formed of a material having visible light transmissibility from the first electrode 101 side, it can be used as a light-emitting device that emits light.

[0281] These conductive materials can be formed into a film using a dry method such as a vacuum evaporation method or a sputtering method, an inkjet method, a spin coating method, etc. Also, it may be formed by a wet method using a sol-gel method, or may be formed by a wet method using a paste of a metal material.

[0282] In the case of a top-emission type light-emitting device, the light extraction efficiency can be improved by forming a cap layer by vapor-depositing an organic compound on the second electrode. The cap layer may have a single-layer structure or a laminated structure. In the case of a laminated structure, it is possible to further improve the light extraction efficiency by using organic compounds having different refractive indexes respectively.

[0283] In addition, as the method for forming the organic compound layer 103, various methods can be used regardless of whether it is a dry method or a wet method. For example, a vacuum evaporation method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method, a spin coating method, or the like may be used.

[0284] Also, each of the above-described electrodes or layers may be formed using different film-forming methods.

[0285] Subsequently, an embodiment of a light-emitting device having a structure in which a plurality of light-emitting units are laminated (also referred to as a laminated device or a tandem device) will be described with reference to FIG. 1(B). This light-emitting device is a light-emitting device having a plurality of light-emitting units between an anode and a cathode. One light-emitting unit has substantially the same configuration as the organic compound layer 103 shown in FIG. 1(A). That is, it can be said that the light-emitting device shown in FIG. 1(B) is a light-emitting device having a plurality of light-emitting units, and the light-emitting device shown in FIG. 1(A) is a light-emitting device having one light-emitting unit.

[0286] In FIG. 1(B), a first light-emitting unit 511 and a second light-emitting unit 512 are laminated between a first electrode 501 and a second electrode 502, and an intermediate layer 513 is provided between the first light-emitting unit 511 and the second light-emitting unit 512. The first electrode 501 and the second electrode 502 respectively correspond to the first electrode 101 and the second electrode 102 in FIG. 1(A), and the same ones as those described in the description of FIG. 1(A) can be applied. Also, the first light-emitting unit 511 and the second light-emitting unit 512 may have the same configuration or different configurations.

[0287] When a voltage is applied to the first electrode 501 and the second electrode 502, the intermediate layer 513 has a function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit. That is, in FIG. 1(B), when a voltage is applied such that the potential of the anode is higher than the potential of the cathode, the intermediate layer 513 may inject electrons into the first light-emitting unit 511 and holes into the second light-emitting unit 512.

[0288] The intermediate layer 513 includes a charge generation layer. The charge generation layer includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material mentioned as a material that can constitute the above-mentioned hole injection layer 111. The P-type layer 117 may also be formed by laminating a film containing an acceptor material and a film containing a hole transport material as materials constituting the composite material. By applying a potential to the P-type layer 117, electrons are injected into the electron transport layer 114 and holes are injected into the cathode, and the light-emitting device operates.

[0289] In addition, in the intermediate layer 513, it is preferable that one or both of an electron relay layer 118 and an N-type layer 119 are provided in addition to the P-type layer 117.

[0290] The electron relay layer 118 includes at least a substance having electron transport properties and has a function of preventing the interaction between the N-type layer 119 and the P-type layer 117 and smoothly transferring electrons. The LUMO level of the substance having electron transport properties contained in the electron relay layer 118 is preferably between the LUMO level of the acceptor substance in the P-type layer 117 and the LUMO level of the substance contained in the layer in contact with the intermediate layer 513 in the electron transport layer 114. The specific energy level of the LUMO level in the substance having electron transport properties used for the electron relay layer 118 is preferably -5.0 eV or more, preferably -5.0 eV or more and -3.0 eV or less. In addition, as the substance having electron transport properties used for the electron relay layer 118, it is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0291] For the N-type layer 119, it is possible to use substances with high electron injection properties such as alkali metals, alkaline earth metals, rare earth metals, and their compounds (including alkali metal compounds (such as oxides like lithium oxide, halides, carbonates like lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds (including oxides, halides, carbonates)).

[0292] Also, when the N-type layer 119 is formed by including a substance with electron transporting properties and a donor substance, as the donor substance, in addition to alkali metals, alkaline earth metals, rare earth metals, and their compounds (including alkali metal compounds (such as oxides like lithium oxide, halides, carbonates like lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or rare earth metal compounds (including oxides, halides, carbonates)), organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, decamethylnickelocene, etc. can also be used. Note that as the substance with electron transporting properties, it can be formed using the same materials as those constituting the electron transport layer 114 described above.

[0293] Also, at the same position as the N-type layer 119, instead of the N-type layer 119, in Embodiment 1, a metal or metal oxide described as being used for the electron injection layer, a first organic compound having a π-electron deficient heteroaromatic ring, and a second organic compound having two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or condensed to each other and have a total of three or more heteroatoms, may be formed. Even in this configuration, a tandem type light-emitting device having good characteristics can be fabricated.

[0294] In addition, when the anode-side surface of the light-emitting unit is in contact with the intermediate layer 513, since the charge generation layer of the intermediate layer 513 can also serve as the hole injection layer of the light-emitting unit, the light-emitting unit does not necessarily need to be provided with a hole injection layer. Further, when the cathode-side surface of the light-emitting unit is in contact with the intermediate layer 513, since the intermediate layer 513 can also serve as the electron injection layer of the light-emitting unit, the light-emitting unit does not necessarily need to be provided with an electron injection layer.

[0295] In FIG. 1(B), a light-emitting device having two light-emitting units has been described, but the same can be similarly applied to a light-emitting device in which three or more light-emitting units are stacked. By arranging a plurality of light-emitting units between a pair of electrodes with the intermediate layer 513 interposed therebetween as in the light-emitting device according to the present embodiment, high-brightness light emission can be achieved while keeping the current density low, and a longer-life element can be realized. Further, a light-emitting device capable of low-voltage driving and having low power consumption can be realized.

[0296] Further, by making the light-emitting colors of the respective light-emitting units different, light emission of a desired color can be obtained for the entire light-emitting device. For example, in a light-emitting device having two light-emitting units, by obtaining a light-emitting color of red and green in the first light-emitting unit and a light-emitting color of blue in the second light-emitting unit, it is also possible to obtain a light-emitting device that emits white light for the entire light-emitting device.

[0297] In addition, each layer and electrode such as the above-described organic compound layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the intermediate layer 513 can be formed by using, for example, a vapor deposition method (including a vacuum vapor deposition method), a droplet discharge method (also referred to as an inkjet method), a coating method, a gravure printing method, or the like. Further, they may contain a low molecular weight material, a medium molecular weight material (including an oligomer and a dendrimer), or a high molecular weight material.

[0298] FIG. 4(A) shows a diagram of two adjacent light-emitting devices (light-emitting device 130a, light-emitting device 130b) included in a display device according to an aspect of the present invention.

[0299] The light-emitting device 130a has an organic compound layer 103a between a first electrode 101a on an insulating layer 175 and a second electrode 102 facing it. Although the organic compound layer 103a is shown as having a configuration including a hole injection layer 111a, a hole transport layer 112a, a light-emitting layer 113a, an electron transport layer 114a, and an electron injection layer 115a, layers having different laminated structures may also be used.

[0300] The light-emitting device 130b has an organic compound layer 103b between a first electrode 101b on an insulating layer 175 and a second electrode 102 facing it. Although the organic compound layer 103b is shown as having a configuration including a hole injection layer 111b, a hole transport layer 112b, a light-emitting layer 113b, an electron transport layer 114b, and an electron injection layer 115b, layers having different laminated structures may also be used.

[0301] The configurations of the electron transport layer 114a and the electron injection layer 115a in the light-emitting device 130a, and the configurations of the electron transport layer 114b and the electron injection layer 115b in the light-emitting device 130b are preferably the configurations as described in Embodiment 1.

[0302] Note that the second electrode 102 is preferably a continuous shared layer in the light-emitting device 130a and the light-emitting device 130b. Also, since the organic compound layer 103a and the organic compound layer 103b are processed by photolithography after the electron injection layer 115a is formed and after the electron injection layer 115b is formed, respectively, they are independent of each other. A light-emitting device according to an aspect of the present invention can obtain a light-emitting device with good characteristics even if it is processed by photolithography after the electron injection layer 115a is formed and after the electron injection layer 115b is formed. Note that, as shown in FIG. 5(A), the electron injection layer 115a and the electron injection layer 115b may be a continuous shared layer in the light-emitting device 130a and the light-emitting device 130b.

[0303] In addition, since the end (outline) of the organic compound layer 103a is processed by photolithography, it is substantially aligned in the direction perpendicular to the substrate. Also, since the end (outline) of the organic compound layer 103b is processed by photolithography, it is substantially aligned in the direction perpendicular to the substrate.

[0304] Moreover, since it is processed by photolithography, a gap d exists between the organic compound layer 103a and the organic compound layer 103b. Also, the distance between the first electrode 101a and the first electrode 101b can be made smaller than when mask evaporation is performed because the organic compound layer is processed by photolithography, and can be set to 0.5 μm or more and 5 μm or less.

[0305] Fig. 4(B) shows a diagram of two adjacent tandem light-emitting devices (light-emitting device 130c, light-emitting device 130d) fabricated by photolithography.

[0306] The light-emitting device 130c has an organic compound layer 103c between the first electrode 101c and the second electrode 102 on the insulating layer 175. The organic compound layer 103c has a structure in which a first light-emitting unit 501c and a second light-emitting unit 502c are laminated with an intermediate layer 116c interposed therebetween. Although Fig. 4(B) shows an example in which two light-emitting units are laminated, a structure in which three or more light-emitting units are laminated may also be used. The first light-emitting unit 501c has a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 116c has a P-type layer 117c, an electron relay layer 118c, and an N-type layer 119c. The electron relay layer 118c may or may not be present. The second light-emitting unit 502c has a second hole transport layer 112c_2, a second light-emitting layer 113c_2, a second electron transport layer 114c_2, and an electron injection layer 115c.

[0307] The light-emitting device 130d has an organic compound layer 103d between a first electrode 101d and a second electrode 102 on an insulating layer 175. The organic compound layer 103d has a structure in which a first light-emitting unit 501d and a second light-emitting unit 502d are laminated with an intermediate layer 116d interposed therebetween. In FIG. 4(B), an example in which two light-emitting units are laminated is shown, but a structure in which three or more light-emitting units are laminated may also be used. The first light-emitting unit 501d includes a hole injection layer 111d, a first hole transport layer 112d_1, a first light-emitting layer 113d_1, and a first electron transport layer 114d_1. The intermediate layer 116d includes a P-type layer 117d, an electron relay layer 118d, and an N-type layer 119d. The electron relay layer 118d may or may not be present. The second light-emitting unit 502d includes a second hole transport layer 112d_2, a second light-emitting layer 113d_2, a second electron transport layer 114d_2, and an electron injection layer 115d.

[0308] In the light-emitting device 130c and the light-emitting device 130d, the electron injection layer 115c and the electron injection layer 115d preferably have the configuration as described in the first embodiment.

[0309] Note that the second electrode 102 is preferably a continuous shared layer in the light-emitting device 130c and the light-emitting device 130d. Further, since the organic compound layer 103c and the organic compound layer 103d are each processed by a photolithography method after the electron injection layer 115c is formed and after the electron injection layer 115d is formed, they are independent of each other. In the light-emitting device according to one aspect of the present invention, even if each is processed by a photolithography method after the electron injection layer 115c is formed and after the electron injection layer 115d is formed, a light-emitting device with good characteristics can be obtained. Note that, as shown in FIG. 5(B), the electron injection layer 115c and the electron injection layer 115d may be a continuous shared layer in the light-emitting device 130c and the light-emitting device 130d.

[0310] Further, since the end (outline) of the organic compound layer 103c is processed by photolithography, it substantially coincides with the substrate in the direction perpendicular to the substrate. Further, since the end (outline) of the organic compound layer 103d is processed by photolithography, it substantially coincides with the substrate in the direction perpendicular to the substrate.

[0311] Further, since it is processed by photolithography, a gap d exists between the organic compound layer 103c and the organic compound layer 103d. Also, the distance between the first electrode 101c and the first electrode 101d can be made smaller than when mask evaporation is performed because the organic compound layer is processed by photolithography, and can be 0.5 μm or more and 5 μm or less.

[0312] Since the light-emitting device according to one aspect of the present invention processes the organic compound layer using photolithography, it can be processed with sufficient accuracy to fabricate a high-definition display device. Further, since the lithography process can be performed on the electron injection layer far from the light-emitting layer without contamination by alkali metals, a light-emitting device with good characteristics can be obtained. As described above, the light-emitting device according to one aspect of the present invention having such a configuration can realize a high-definition display device and can be a light-emitting device with good characteristics.

[0313] Note that since the organic compound layer in the light-emitting device according to one aspect of the present invention is processed at once using photolithography, the outlines of all the layers included in the organic compound layer substantially coincide. Here, the term "substantially coincide" in this specification means that the deviation between the outline A of layer A and the outline B of layer B included in the organic compound layer is within 5% of the width of the organic compound layer on a line perpendicular to the outline of the portion to be compared. Also, when the end face of the organic compound layer has a tapered shape, a continuous change in the outline is allowed.

[0314] The configuration of this embodiment can be used in appropriate combination with other configurations.

[0315] (Embodiment 3) As illustrated in FIGS. 6(A) and 6(B), the light-emitting device 130 includes a plurality of display devices formed on the insulating layer 175. In this embodiment, a display device according to an aspect of the present invention will be described in detail.

[0316] The display device 100 has a pixel portion 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 includes a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0317] In this specification and the like, for example, when describing matters common to the sub-pixel 110R, the sub-pixel 110G, and the sub-pixel 110B, they may be described by referring to them as the sub-pixel 110. For other components distinguished by alphabets, when describing matters common to them, they may be described using symbols with the alphabets omitted.

[0318] The sub-pixel 110R exhibits red light, the sub-pixel 110G exhibits green light, and the sub-pixel 110B exhibits blue light. Thereby, an image can be displayed on the pixel portion 177. In this embodiment, three-color sub-pixels of red (R), green (G), and blue (B) are described as an example, but combinations of sub-pixels of other colors may also be used. Further, the number of sub-pixels is not limited to three and may be four or more. Examples of four sub-pixels include four-color sub-pixels of R, G, B, and white (W), four-color sub-pixels of R, G, B, and Y, and four sub-pixels of R, G, B, and infrared light (IR).

[0319] In this specification and the like, the row direction may be referred to as the X direction and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly.

[0320] FIG. 6(A) shows an example in which sub-pixels of different colors are arranged side by side in the X direction, and sub-pixels of the same color are arranged side by side in the Y direction. Note that sub-pixels of different colors may be arranged side by side in the Y direction, and sub-pixels of the same color may be arranged side by side in the X direction.

[0321] Outside the pixel portion 177, a connection portion 140 may be provided, and an area 141 may be provided. The area 141 is provided between the pixel portion 177 and the connection portion 140. An organic compound layer 103 is provided in the area 141. Also, a conductive layer 151C is provided in the connection portion 140.

[0322] In FIG. 6(A), an example where the area 141 and the connection portion 140 are located on the right side of the pixel portion 177 is shown, but the positions of the area 141 and the connection portion 140 are not particularly limited. Also, the area 141 and the connection portion 140 may be singular or plural.

[0323] FIG. 6(B) is an example of a cross-sectional view between the dashed-dotted line A1 - A2 in FIG. 6(A). As shown in FIG. 6(B), the display device 100 includes an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). Openings reaching the conductive layer 172 are provided in the insulating layer 175, the insulating layer 174, and the insulating layer 173, and plugs 176 are provided so as to fill the openings.

[0324] In the pixel portion 177, a light-emitting device 130 is provided on the insulating layer 175 and the plug 176. Also, a protective layer 131 is provided so as to cover the light-emitting device 130. The substrate 120 is bonded by a resin layer 122 on the protective layer 131. Also, between adjacent light-emitting devices 130, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are preferably provided.

[0325] In FIG. 6(B), a plurality of cross-sections of the inorganic insulating layer 125 and the insulating layer 127 are shown, but when the display device 100 is viewed from above, the inorganic insulating layer 125 and the insulating layer 127 are preferably connected to each other as one. That is, the inorganic insulating layer 125 and the insulating layer 127 are preferably insulating layers having openings on the first electrode.

[0326] In Fig. 6(B), light-emitting devices 130R, 130G, and 130B are shown as the light-emitting device 130. The light-emitting devices 130R, 130G, and 130B shall have different emission colors from each other. For example, the light-emitting device 130R can emit red light, the light-emitting device 130G can emit green light, and the light-emitting device 130B can emit blue light. Also, the light-emitting device 130R, 130G, or 130B may emit other visible light or infrared light.

[0327] The display device according to one aspect of the present invention can be a top emission type that emits light in a direction opposite to the substrate on which, for example, the light-emitting device is formed. Note that the display device according to one aspect of the present invention may be a bottom emission type.

[0328] Examples of the light-emitting substance included in the light-emitting device 130 include organic compounds or organometallic complexes such as substances that emit fluorescence (fluorescent materials), substances that emit phosphorescence (phosphorescent materials), and substances that exhibit thermally activated delayed fluorescence (thermally activated delayed fluorescence (TADF) materials). Inorganic compounds such as quantum dots may also be used.

[0329] The light-emitting device 130R has a configuration as shown in Embodiment 1. It has a first electrode (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer 104. Note that the common layer 104 may or may not be provided, but it is preferable to provide it because it can reduce damage to the organic compound layer 103R during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. Also, when the common layer 104 is provided, the laminated structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 2.

[0330] The light-emitting device 130G has a configuration as shown in Embodiment 1. It has a first electrode (pixel electrode) composed of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer 104. Note that the common layer 104 may or may not be provided, but it is preferable to provide it because it can reduce damage to the organic compound layer 103G during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. Also, when the common layer 104 is provided, the laminated structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 2.

[0331] The light-emitting device 130B has a configuration as shown in Embodiment 1. It has a first electrode (pixel electrode) composed of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer 104. Note that the common layer 104 may or may not be provided, but it is preferable to provide it because it can reduce damage to the organic compound layer 103B during processing. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. Also, when the common layer 104 is provided, the laminated structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103 in Embodiment 2.

[0332] Of the pixel electrode and the common electrode that the light-emitting device has, one functions as an anode and the other functions as a cathode. Hereinafter, unless otherwise specified, it will be described assuming that the pixel electrode functions as an anode and the common electrode functions as a cathode.

[0333] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are independent in an island shape for each light-emitting device or for each emission color. By providing the organic compound layer 103 in an island shape for each light-emitting device 130, it is possible to suppress the leakage current between adjacent light-emitting devices 130 even in a high-definition display device. As a result, crosstalk can be prevented, and a display device with extremely high contrast can be realized. In particular, a display device with high current efficiency at low luminance can be realized.

[0334] The island-shaped organic compound layer 103 is formed by forming an EL film and processing the EL film using a lithography method.

[0335] In addition, in the display device according to one aspect of the present invention, it is preferable that the first electrode (pixel electrode) of the light-emitting device has a laminated structure. For example, in the example shown in FIG. 6(B), the first electrode of the light-emitting device 130 has a laminated structure of a conductive layer 151 and a conductive layer 152. For example, when the display device 100 is a top emission type and the pixel electrode of the light-emitting device 130 functions as an anode, the conductive layer 151 is preferably a layer with a high reflectance for visible light, and the conductive layer 152 is preferably a layer having, for example, visible light transmittance and a large work function. When the display device 100 is a top emission type, the higher the reflectance of the pixel electrode for visible light, the higher the light extraction efficiency of the light emitted from the organic compound layer 103. Further, when the pixel electrode functions as an anode, the larger the work function of the pixel electrode, the easier the injection of holes into the organic compound layer 103. From the above, by forming the pixel electrode of the light-emitting device 130 into a laminated structure of a conductive layer 151 with a high reflectance for visible light and a conductive layer 152 with a large work function, the light-emitting device 130 can be made into a light-emitting device with high light extraction efficiency and low driving voltage.

[0336] When the conductive layer 151 is a layer with a high reflectance to visible light, the reflectance of the conductive layer 151 to visible light is preferably, for example, 40% or more and 100% or less, or 70% or more and 100% or less. Further, when the conductive layer 152 is an electrode having visible light transmissivity, the transmittance to visible light is preferably, for example, 40% or more.

[0337] Here, when the pixel electrode has a stacked structure composed of a plurality of layers, for example, the pixel electrode may be deteriorated due to the reaction between the plurality of layers. For example, when removing the film formed after the formation of the pixel electrode by a wet etching method, galvanic corrosion may occur due to the chemical solution coming into contact with the pixel electrode.

[0338] Therefore, in the display device 100 of the present embodiment, an insulating layer 156 is formed on the side surfaces of the conductive layer 151 and the conductive layer 152. Thereby, even when removing the film formed after the formation of the pixel electrode having, for example, the conductive layer 151 and the conductive layer 152 by a wet etching method, it is possible to suppress the chemical solution from coming into contact with the conductive layer 151. Therefore, for example, the occurrence of galvanic corrosion on the pixel electrode can be suppressed. Thus, since the display device 100 can be manufactured by a method with a high yield, it can be a low-cost display device. In addition, since the occurrence of defects in the display device 100 can be suppressed, the display device 100 can be a highly reliable display device.

[0339] As the conductive layer 151, for example, a metal material can be used. Specifically, for example, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), etc., and alloys containing these appropriately combined can also be used.

[0340] As the conductive layer 152, an oxide containing any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing any one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, the work function is 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0341] The conductive layer 151 may have a laminated structure of a plurality of layers having different materials, and the conductive layer 152 may also have a laminated structure of a plurality of layers having different materials. In this case, the conductive layer 151 may have a layer using a material that can be used for the conductive layer 152 such as a conductive oxide, and the conductive layer 152 may also have a layer using a material that can be used for the conductive layer 151 such as a metal material. For example, when the conductive layer 151 has a laminated structure of two or more layers, the layer in contact with the conductive layer 152 can be a layer using a material that can be used for the conductive layer 152.

[0342] Note that the end portion of the insulating layer 156 may have a tapered shape. Specifically, by having the end portion of the insulating layer 156 have a tapered shape with a taper angle of less than 90°, the covering property of the structure provided along the side surface of the insulating layer 156 can be enhanced.

[0343] FIG. 7(A) shows a diagram of the case where the conductive layer 151 has a laminated structure of a plurality of layers containing different materials. As shown in FIG. 7(A), the conductive layer 151 has a configuration including a conductive layer 151a, a conductive layer 151b on the conductive layer 151a, and a conductive layer 151c on the conductive layer 151b. That is, the conductive layer 151 shown in FIG. 7(A) has a three-layer laminated configuration. Thus, when the conductive layer 151 has a laminated structure of a plurality of layers, the reflectance of at least one of the layers constituting the conductive layer 151 with respect to visible light may be made higher than the reflectance of the conductive layer 152 with respect to visible light.

[0344] In the example shown in FIG. 7(A), the conductive layer 151b is configured to be sandwiched between the conductive layer 151a and the conductive layer 151c. It is preferable to use a material that is less likely to be deteriorated than the conductive layer 151b for the conductive layer 151a and the conductive layer 151c. For example, for the conductive layer 151a, a material can be used in which the occurrence of migration due to contact with the insulating layer 175 is less likely to occur than in the conductive layer 151b. Further, for the conductive layer 151c, a material can be used that is less likely to be oxidized than the conductive layer 151b and in which the electrical resistivity of the oxide is lower than that of the oxide of the material used for the conductive layer 151b.

[0345] From the above, by adopting a configuration in which the conductive layer 151b is sandwiched between the conductive layer 151a and the conductive layer 151c, the range of material selection for the conductive layer 151b can be widened. Thereby, for example, the conductive layer 151b can be made a layer having a higher reflectance with respect to visible light than at least one of the conductive layer 151a and the conductive layer 151c. For example, aluminum can be used as the conductive layer 151b. Note that an alloy containing aluminum may be used for the conductive layer 151b. Further, as the conductive layer 151a, titanium, which has a lower reflectance with respect to visible light compared to aluminum but is less likely to cause migration than aluminum even when in contact with the insulating layer 175, can be used. Furthermore, as the conductive layer 151c, titanium, which has a lower reflectance with respect to visible light compared to aluminum but is less likely to be oxidized than aluminum and in which the electrical resistivity of the oxide is lower than that of aluminum oxide, can be used.

[0346] Further, as the conductive layer 151c, silver or an alloy containing silver may be used. Silver has the property that the reflectance with respect to visible light is higher than that of titanium. Further, silver is less likely to be oxidized than aluminum, and silver oxide has a lower resistivity than aluminum oxide. As described above, when silver or an alloy containing silver is used as the conductive layer 151c, the reflectance of the conductive layer 151 with respect to visible light can be suitably increased, and an increase in the electrical resistance of the pixel electrode due to oxidation of the conductive layer 151b can be suppressed. Here, as the alloy containing silver, for example, an alloy of silver, palladium, and copper (also denoted as Ag-Pd-Cu, APC) can be applied. Note that when silver or an alloy containing silver is used as the conductive layer 151c and aluminum is used as the conductive layer 151b, the reflectance of the conductive layer 151c with respect to visible light can be made higher than the reflectance of the conductive layer 151b with respect to visible light. Here, silver or an alloy containing silver may be used as the conductive layer 151b. Further, silver or an alloy containing silver may be used for the conductive layer 151a.

[0347] On the other hand, a film using titanium is superior in processability by etching to a film using silver. Therefore, by using titanium as the conductive layer 151c, the conductive layer 151c can be easily formed. Note that a film using aluminum is also superior in processability by etching to a film using silver.

[0348] As described above, by forming the conductive layer 151 in a stacked structure of a plurality of layers, the characteristics of the display device can be improved. For example, the display device 100 can be made into a display device with high light extraction efficiency and high reliability.

[0349] Here, when a microcavity structure is applied to the light-emitting device 130, if silver or an alloy containing silver, which is a material with a high reflectance with respect to visible light, is used as the conductive layer 151c, the light extraction efficiency of the display device 100 can be suitably increased.

[0350] As described above, the side surface of the conductive layer 151 preferably has a tapered shape. Specifically, the side surface of the conductive layer 151 preferably has a tapered shape with a taper angle of less than 90°. For example, in the conductive layer 151 having the configuration shown in FIG. 7(A), at least one side surface of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c preferably has a tapered shape.

[0351] The conductive layer 151 shown in FIG. 7(A) can be formed using a lithography method. Specifically, first, a conductive film to be the conductive layer 151a, a conductive film to be the conductive layer 151b, and a conductive film to be the conductive layer 151c are formed in sequence. Next, a resist mask is formed on the conductive film to be the conductive layer 151c. Then, the conductive film in the region that does not overlap with the resist mask is removed using, for example, an etching method. Here, by processing the conductive film under conditions where the resist mask is likely to recede (shrink), that is, conditions where the side surface is not tapered, i.e., the side surface is perpendicular, the side surface of the conductive layer 151 can be made into a tapered shape.

[0352] Here, when the conductive film is processed under conditions where the resist mask is likely to recede (shrink), the conductive film may be easily processed in the horizontal direction. That is, the etch anisotropy may be higher than when the conductive layer 151 is formed such that the side surface is perpendicular.

[0353] Also, when the conductive layer 151 has a laminated structure of a plurality of layers made of different materials, the ease of horizontal processing may be different between the plurality of layers. For example, the ease of horizontal processing may be different between the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c.

[0354] In this case, after processing the conductive film, as shown in FIG. 7(A), the side surface of the conductive layer 151b may be located inside the side surfaces of the conductive layer 151a and the conductive layer 151c, forming a protruding portion. As a result, the covering property of the conductive layer 152 with respect to the conductive layer 151 may decrease, and there may be a risk of step breakage in the conductive layer 152.

[0355] Therefore, it is preferable to provide the insulating layer 156 as shown in FIG. 7(A). FIG. 7(A) shows an example in which the insulating layer 156 is provided on the conductive layer 151a so as to have a region overlapping with the side surface of the conductive layer 151b. Thereby, since the occurrence of step discontinuity or thinning of the conductive layer 152 due to the protrusion can be suppressed, connection failure or increase in driving voltage can be suppressed.

[0356] In FIG. 7(A), a structure in which the side surface of the conductive layer 151b is entirely covered with the insulating layer 156 is illustrated, but a part of the side surface of the conductive layer 151b may not be covered with the insulating layer 156. Similarly, in the pixel electrode having the configuration shown hereinafter, a part of the side surface of the conductive layer 151b may not be covered with the insulating layer 156.

[0357] When the conductive layer 151 has the configuration shown in FIG. 7(A), the conductive layer 152 is provided so as to cover the conductive layer 151a, the conductive layer 151b, the conductive layer 151c, and the insulating layer 156 and to be electrically connected to the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c. Thereby, even when a film formed after the formation of the conductive layer 152 is removed by a wet etching method, the chemical solution can be prevented from coming into contact with any of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c. Therefore, corrosion can be suppressed in any of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c. Therefore, the display device 100 can be manufactured by a method with high yield. In addition, the occurrence of defects is suppressed, and the display device 100 can be a highly reliable display device.

[0358] Here, as shown in FIG. 7(A), the insulating layer 156 preferably has a curved surface. This can suppress the occurrence of steps in the conductive layer 152 covering the insulating layer 156 as compared to, for example, the case where the side surface of the insulating layer 156 is perpendicular (parallel to the Z direction). Further, even when the insulating layer 156 has a tapered shape on its side surface, specifically, a tapered shape with a taper angle of less than 90°, the occurrence of steps in the conductive layer 152 covering the insulating layer 156 can be suppressed as compared to, for example, the case where the side surface of the insulating layer 156 is perpendicular. From the above, the display device 100 can be manufactured by a method with a high yield. Also, the occurrence of defects can be suppressed, and the display device 100 can be a highly reliable display device.

[0359] Note that in FIG. 7(A), a configuration is shown in which the side surface of the conductive layer 151b is located inside the side surfaces of the conductive layer 151a and the conductive layer 151c, but one aspect of the present invention is not limited to this. For example, the side surface of the conductive layer 151b may be located outside the side surface of the conductive layer 151a. Also, the side surface of the conductive layer 151b may be located outside the side surface of the conductive layer 151c.

[0360] FIGS. 7(B) to 7(D) show other configurations of the first electrode 101. FIG. 7(B) shows a configuration in which in the first electrode 101 of FIG. 7(A), the insulating layer 156 covers not only the side surface of the conductive layer 151b but also the side surfaces of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c.

[0361] FIG. 7(C) shows a configuration in which the insulating layer 156 is not provided in the first electrode 101 of FIG. 7(A).

[0362] FIG. 7(D) shows a configuration in which in the first electrode 101 of FIG. 7(A), the conductive layer 151 does not have a laminated structure and the conductive layer 152 has a laminated structure.

[0363] The conductive layer 152a is a layer with an adhesion to the conductive layer 152b higher than, for example, that of the insulating layer 175. As the conductive layer 152a, an oxide containing any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing any one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium titanium oxide, zinc titanate, aluminum zinc oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. Thus, peeling of the conductive layer 152b can be suppressed. Also, the conductive layer 152b can be configured not to be in contact with the insulating layer 175.

[0364] The conductive layer 152b is a layer with a reflectance to visible light (for example, the reflectance to light of a predetermined wavelength within the range of 400 nm or more and less than 750 nm) higher than those of the conductive layer 151, the conductive layer 152a, and the conductive layer 152c. The reflectance of the conductive layer 152b to visible light can be, for example, 70% or more and 100% or less, preferably 80% or more and 100% or less, and more preferably 90% or more and 100% or less. Also, as the conductive layer 152b, a material with a higher reflectance to visible light than, for example, aluminum can be used. Specifically, as the conductive layer 152b, for example, silver or an alloy containing silver can be used. Examples of the alloy containing silver include an alloy of silver, palladium, and copper (APC). Thus, the display device 100 can be made into a display device with high light extraction efficiency. Note that a metal other than silver may be used as the conductive layer 152b.

[0365] When the conductive layer 152c functions as an anode together with the conductive layer 151 and the conductive layer 152, it is preferably a layer having a large work function. For example, the conductive layer 152c is a layer having a larger work function than the conductive layer 152b. As the conductive layer 152c, for example, the same material as that used for the conductive layer 152a can be used. For example, a configuration can be adopted in which the same type of material is used for the conductive layer 152a and the conductive layer 152c. For example, when indium tin oxide is used for the conductive layer 152a, indium tin oxide can also be used for the conductive layer 152c.

[0366] When the conductive layer 151 and the conductive layer 152 function as cathodes, it is preferably a layer having a small work function. For example, the conductive layer 152c is a layer having a smaller work function than the conductive layer 152b.

[0367] In addition, the conductive layer 152c is preferably a layer having a high transmittance for visible light (for example, the transmittance for light of a predetermined wavelength in the range of 400 nm or more and less than 750 nm). For example, the transmittance of the conductive layer 152c for visible light is preferably higher than the transmittances of the conductive layer 151 and the conductive layer 152b for visible light. For example, the transmittance of the conductive layer 152c for visible light can be 60% or more and 100% or less, preferably 70% or more and 100% or less, and more preferably 80% or more and 100% or less. As described above, the amount of light absorbed by the conductive layer 152c among the light emitted by the organic compound layer 103 can be reduced. Also, as described above, the conductive layer 152b under the conductive layer 152c can be a layer having a high reflectance for visible light. Therefore, the display device 100 can be a display device having high light extraction efficiency.

[0368] Next, an example of a method for manufacturing the display device 100 having the configuration shown in FIG. 6(A) will be described with reference to FIGS. 8 to 13. The light-emitting device included in the display device 100 has an organic layer formed by a manufacturing process including a treatment using water. By using the organic compound according to one aspect of the present invention for the organic layer of the light-emitting device included in the display device according to one aspect of the present invention, even when manufactured by a manufacturing method including a treatment using water, problems such as dissolution of the layer containing the organic compound and penetration of a chemical solution into the layer using the organic compound can be prevented, and a light-emitting device having good characteristics can be provided.

[0369] [Example of manufacturing method] The thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, or the like. Examples of the CVD method include a plasma enhanced CVD (PECVD) method and a thermal CVD method. Further, one type of the thermal CVD method is a metal organic CVD (MOCVD) method.

[0370] In addition, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by a wet film-forming method such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0371] In particular, for the fabrication of a light-emitting device, a vacuum process such as a vapor deposition method and a solution process such as a spin coating method or an inkjet method can be used. Examples of the vapor deposition method include physical vapor deposition (PVD) methods such as a sputtering method, an ion plating method, an ion beam evaporation method, a molecular beam epitaxy method, and a vacuum evaporation method, and a chemical vapor deposition (CVD) method. In particular, for functional layers (such as a hole injection layer, a hole transport layer, a hole blocking layer, a light-emitting layer, an electron blocking layer, an electron transport layer, and an electron injection layer) included in an organic compound layer, a vapor deposition method (such as a vacuum evaporation method), a coating method (such as a dip coating method, a die coating method, a bar coating method, a spin coating method, or a spray coating method), a printing method (such as an inkjet method, a screen (stencil printing) method, an offset (lithographic printing) method, a flexo (letterpress printing) method, a gravure method, or a microcontact method), or the like can be used to form the layers.

[0372] In addition, when processing a thin film constituting a display device, for example, a lithography method can be used. Alternatively, the thin film may be processed by a nanoimprint method, a sandblasting method, a lift-off method, or the like. Also, an island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0373] As the lithography method, for example, a photolithography method can be used. Typically, there are the following two representative photolithography methods. One is a method in which a resist mask is formed on a thin film to be processed, the thin film is processed by, for example, etching, and then the resist mask is removed. The other is a method in which a photosensitive thin film is formed and then exposed and developed to process the thin film into a desired shape.

[0374] In photolithography, as the light used for exposure, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or light obtained by mixing these can be used. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. can also be used. Further, exposure may be performed by immersion lithography technology. Also, as the light used for exposure, extreme ultraviolet (EUV) light or X-rays may be used. Further, instead of the light used for exposure, an electron beam can also be used. Using extreme ultraviolet light, X-rays or an electron beam is preferable because extremely fine processing becomes possible. Note that when performing exposure by scanning a beam such as an electron beam, a photomask is not required.

[0375] For etching a thin film, a dry etching method, a wet etching method, a sandblasting method, or the like can be used.

[0376] First, as shown in FIG. 8(A), an insulating layer 171 is formed on a substrate (not shown). Subsequently, a conductive layer 172 and a conductive layer 179 are formed on the insulating layer 171, and an insulating layer 173 is formed on the insulating layer 171 so as to cover the conductive layer 172 and the conductive layer 179. Subsequently, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0377] As the substrate, a substrate having heat resistance sufficient to withstand at least subsequent heat treatment can be used. When an insulating substrate is used as the substrate, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like can be used. Further, a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, a semiconductor substrate such as an SOI substrate can be used.

[0378] Subsequently, as shown in FIG. 8(A), an opening reaching the conductive layer 172 is formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Subsequently, a plug 176 is formed so as to fill the opening.

[0379] Subsequently, as shown in FIG. 8(A), a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, is formed on the plug 176 and on the insulating layer 175. For forming the conductive film 151f, for example, a sputtering method or a vacuum evaporation method can be used. Also, as the conductive film 151f, for example, a metal material can be used.

[0380] Subsequently, as shown in FIG. 8(A), a conductive film 152f, which will later become the conductive layers 152R, 152G, 152B, and 152C, is formed on the conductive film 151f. For forming the conductive film 152f, for example, a sputtering method or a vacuum evaporation method can be used. Also, as the conductive film 152f, for example, a conductive oxide can be used. Or, a laminated structure of a film using a metal material and a film using a conductive oxide on the said film can be applied. For example, a laminated structure of a film using titanium, silver, or an alloy containing silver and a film using a conductive oxide on the said film can be applied.

[0381] Also, for forming the conductive film 152f, an ALD method can be used. In this case, as the conductive film 152f, an oxide having any one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. In this case, the introduction of a precursor (generally sometimes called a precursor or a metal precursor, etc.), the purge of the said precursor, the introduction of an oxidizing agent (generally sometimes called a reactant, a reactant, or a non-metal precursor, etc.), and the purge of the said oxidizing agent are taken as one cycle, and by repeating the said cycle, the conductive film 152f can be formed. Here, when forming an oxide film containing a plurality of kinds of metals, such as indium tin oxide, as the conductive film 152f, the composition of the metal can be controlled by varying the number of cycles for each type of precursor.

[0382] For example, when forming an indium tin oxide film as the conductive film 152f, after introducing a precursor containing indium, the precursor is purged and an oxidizing agent is introduced to form an In-O film. Next, after introducing a precursor containing tin, the precursor is purged and an oxidizing agent is introduced to form a Sn-O film. Here, by making the number of cycles of In-O film formation larger than the number of cycles of Sn-O film formation, the number of indium atoms contained in the conductive film 152f can be made larger than the number of tin atoms.

[0383] Also, for example, when forming a zinc oxide film as the conductive film 152f, a Zn-O film is formed by the above procedure. Also, for example, when forming an aluminum zinc oxide film as the conductive film 152f, a Zn-O film and an Al-O film are each formed by the above procedure. Also, for example, when forming a titanium oxide film as the conductive film 152f, a Ti-O film is formed by the above procedure. Also, for example, when forming an indium tin oxide film containing silicon as the conductive film 152f, an In-O film, a Sn-O film, and a Si-O film are formed by the above procedure. Also, for example, when forming a zinc oxide film containing gallium, a Ga-O film and a Zn-O film are formed by the above procedure.

[0384] As precursors containing indium, for example, triethylindium, trimethylindium, or [1,1,1-trimethyl-N-(trimethylsilyl)amide]-indium can be used. As precursors containing tin, for example, tin chloride, or tetrakis(dimethylamide)tin can be used. As precursors containing zinc, for example, diethylzinc, or dimethylzinc can be used. As precursors containing gallium, for example, triethylgallium can be used. As precursors containing titanium, for example, titanium chloride, tetrakis(dimethylamide)titanium, or tetraisopropyl titanate can be used. As precursors containing aluminum, for example, aluminum chloride, or trimethylaluminum can be used. As precursors containing silicon, trisilylamine, bis(diethylamino)silane, tris(dimethylamino)silane, bis(tert-butylamino)silane, or bis(ethylmethylamino)silane can be used. Further, as the oxidizing agent, water vapor, oxygen plasma, or ozone gas can be used.

[0385] Subsequently, as shown in FIG. 8(A), a resist mask 191 is formed on the conductive film 151f and the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist) and performing exposure and development.

[0386] Subsequently, as shown in FIG. 8(B), for example, the conductive film 151f and the conductive film 152f in a region that does not overlap with the resist mask 191 are removed using, for example, an etching method, specifically, for example, a dry etching method, to form a pixel electrode having a conductive layer 151 and a conductive layer 152. When the conductive film 151f includes a layer using a conductive oxide such as indium tin oxide, the layer may be removed using a wet etching method. Thereby, the conductive layer 151 and the conductive layer 152 are formed. When a part of the conductive film 151f is removed by a dry etching method, for example, a recess may be formed in a region that does not overlap with the conductive layer 151 of the insulating layer 175.

[0387] Note that after processing the conductive film 152f using a lithography method to form the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C, the conductive film 151f may be processed using the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C as masks. Specifically, for example, after forming a resist mask, a part of the conductive film 152f is removed by an etching method. The conductive film 152f can be removed, for example, by a wet etching method. Note that the conductive film 152f may be removed by a dry etching method. Thereafter, the conductive film 151f may be removed by a wet etching method.

[0388] Here, it is preferable to perform a hydrophobization treatment on the conductive layer 152. In the hydrophobization treatment, the surface to be treated can be changed from hydrophilic to hydrophobic, or the hydrophobicity of the surface to be treated can be enhanced. By performing the hydrophobization treatment on the conductive layer 152, the adhesion between the conductive layer 152 and the organic compound layer 103 formed in a later step can be enhanced, and film peeling can be suppressed. Note that the hydrophobization treatment may not be performed.

[0389] Subsequently, as shown in FIG. 8(C), the resist mask 191 is removed. The resist mask 191 can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and a Group 18 element such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 191 may be removed by wet etching.

[0390] Subsequently, as shown in FIG. 8(D), an insulating film 156f that will later become the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, and the insulating layer 156C is formed on the conductive layer 151R and the conductive layer 152R, on the conductive layer 151G and the conductive layer 152G, on the conductive layer 151B and the conductive layer 152B, on the conductive layer 151C and the conductive layer 152C, and on the insulating layer 175. For the formation of the insulating film 156f, for example, a CVD method, an ALD method, a sputtering method, or a vacuum evaporation method can be used.

[0391] For the insulating film 156f, an inorganic material can be used. As the insulating film 156f, for example, an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitroxide insulating film can be used. For example, as the insulating film 156f, an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitroxide insulating film containing silicon can be used. For example, silicon oxynitride can be used as the insulating film 156f.

[0392] Subsequently, as shown in FIG. 8(E), by processing the insulating film 156f, an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C are formed. For example, by performing etching substantially uniformly on the upper surface of the insulating film 156f, the insulating layer 156 can be formed. Performing etching and planarization uniformly in this way is also called etch-back processing. Note that the insulating layer 156 may be formed using a lithography method.

[0393] Subsequently, as shown in FIG. 9(A), an organic compound film 103Rf that will later become the organic compound layer 103R is formed on the conductive layer 152R, on the conductive layer 152G, on the conductive layer 152B, on the insulating layer 156R, on the insulating layer 156G, on the insulating layer 156B, and on the insulating layer 175.

[0394] As shown in FIG. 9(A), the organic compound film 103Rf is not formed on the conductive layer 152C. For example, by using a mask for defining a film formation area (also referred to as an area mask or a rough metal mask, etc., distinguished from a fine metal mask), the organic compound film 103Rf can be formed only in a desired region. By adopting a film formation process using an area mask and a processing process using a resist mask, a light-emitting device can be manufactured with a relatively simple process.

[0395] The organic compound film 103Rf can be formed, for example, by a vapor deposition method, specifically, a vacuum vapor deposition method. Further, the organic compound film 103Rf may be formed by a method such as a transfer method, a printing method, an inkjet method, or a coating method.

[0396] Subsequently, as shown in FIG. 9(A), a sacrificial film 158Rf that will later become the sacrificial layer 158R and a mask film 159Rf that will later become the mask layer 159R are sequentially formed on the organic compound film 103Rf, on the conductive layer 152C, and on the insulating layer 175.

[0397] In this embodiment, an example of forming a mask film with a two-layer structure of a sacrificial film 158Rf and a mask film 159Rf is shown. However, the mask film may have a single-layer structure or a laminated structure of three or more layers.

[0398] By providing a sacrificial layer on the organic compound film 103Rf, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0399] For the sacrificial film 158Rf, a film with high resistance to the processing conditions of the organic compound film 103Rf is used. Specifically, a film with a large etching selectivity ratio with respect to the organic compound film 103Rf is used. For the mask film 159Rf, a film with a large etching selectivity ratio with respect to the sacrificial film 158Rf is used.

[0400] Also, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat-resistant temperature of the organic compound film 103Rf. As the substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf, typically, they are each 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower, and even more preferably 80°C or lower.

[0401] It is preferable to use a film that can be removed by a wet etching method for the sacrificial film 158Rf and the mask film 159Rf. By using the wet etching method, damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to the case of using a dry etching method.

[0402] For the formation of the sacrificial film 158Rf and the mask film 159Rf, for example, a sputtering method, an ALD method (thermal ALD method, PEALD method), a CVD method, or a vacuum evaporation method can be used. Further, it may be formed using the above-described wet film formation method.

[0403] Note that the sacrificial film 158Rf formed in contact with the organic compound film 103Rf is preferably formed using a formation method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, it is preferable to form the sacrificial film 158Rf using an ALD method or a vacuum evaporation method rather than a sputtering method.

[0404] As the sacrificial film 158Rf and the mask film 159Rf, one or more of, for example, a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, and an inorganic insulating film can be used respectively.

[0405] For the sacrificial film 158Rf and the mask film 159Rf, respectively, for example, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing the metal materials can be used. In particular, it is preferable to use a low melting point material such as aluminum or silver. By using a metal material capable of shielding ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf, irradiation of the organic compound film 103Rf with ultraviolet rays can be suppressed, and deterioration of the organic compound film 103Rf can be suppressed, which is preferable.

[0406] Further, for the sacrificial film 158Rf and the mask film 159Rf, respectively, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanate (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), and indium tin oxide containing silicon can be used.

[0407] In addition, instead of the above-mentioned gallium, an element M (M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used.

[0408] Also, as the sacrificial film and the mask film, it is preferable to use a film containing a material having light-shielding properties against light, particularly ultraviolet light. As the material having light-shielding properties, various materials such as a metal, an insulator, a semiconductor, and a semimetal having light-shielding properties against ultraviolet light can be used. However, since a part or all of the sacrificial film and the mask film are removed in a later process, it is preferable that the film is processable by etching, and particularly preferably, it has good processability.

[0409] As the sacrificial film and the mask film, for example, a semiconductor material such as silicon or germanium is preferable because it has high affinity with the semiconductor manufacturing process. Alternatively, an oxide or a nitride of the above semiconductor material can be used. Alternatively, a non-metallic material such as carbon or a compound thereof can be used. Alternatively, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or an alloy containing one or more of these can be mentioned. Alternatively, an oxide containing the above metal such as titanium oxide or chromium oxide, or a nitride such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0410] By using a film containing a material having light-shielding properties against ultraviolet light for the sacrificial film and the mask film, for example, it is possible to suppress the irradiation of ultraviolet light to the organic compound layer in the exposure process. By suppressing the damage of the organic compound layer by ultraviolet light, the reliability of the light-emitting device can be improved.

[0411] Note that a film containing a material having light-shielding properties against ultraviolet light can also be used as the material of the inorganic insulating film 125f described later, and the same effect can be obtained.

[0412] In addition, various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, the oxide insulating film is preferable because it has higher adhesion to the organic compound film 103Rf than the nitride insulating film. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the sacrificial film 158Rf and the mask film 159Rf, respectively. As the sacrificial film 158Rf and the mask film 159Rf, for example, an aluminum oxide film can be formed using the ALD method. Using the ALD method is preferable because it can reduce damage to the substrate (especially the organic compound layer).

[0413] For example, as the sacrificial film 158Rf, an inorganic insulating film (for example, an aluminum oxide film) formed using the ALD method can be used, and as the mask film 159Rf, an inorganic film (for example, an In-Ga-Zn oxide film, an aluminum film, or a tungsten film) formed using the sputtering method can be used.

[0414] Note that the same inorganic insulating film can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125 to be formed later. For example, an aluminum oxide film formed using the ALD method can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125. Here, the same film formation conditions may be applied to the sacrificial film 158Rf and the inorganic insulating layer 125, or different film formation conditions may be applied to each other. For example, by forming the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, the sacrificial film 158Rf can be made into an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, since the sacrificial film 158Rf is a layer that is mostly or entirely removed in a later process, it is preferably easy to process. Therefore, the sacrificial film 158Rf is preferably formed under conditions where the substrate temperature during film formation is lower than that of the inorganic insulating layer 125.

[0415] One or both of the sacrificial film 158Rf and the mask film 159Rf may use an organic material. For example, as the organic material, a material that can be dissolved in a solvent that is chemically stable with respect to at least the film located at the top of the organic compound film 103Rf may be used. In particular, a material that can be dissolved in water or alcohol can be preferably used. When forming a film of such a material, it is preferable to perform a heat treatment for evaporating the solvent after coating in a wet film-forming method in a state of being dissolved in a solvent such as water or alcohol. At this time, by performing the heat treatment under a reduced-pressure atmosphere, the solvent can be removed at a low temperature and in a short time, so that thermal damage to the organic compound film 103Rf can be reduced, which is preferable.

[0416] For the sacrificial film 158Rf and the mask film 159Rf, organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin, or fluororesin such as perfluoropolymer may be used respectively.

[0417] For example, as the sacrificial film 158Rf, an organic film (for example, a PVA film) formed by using either vapor deposition or the above wet film-forming method can be used, and as the mask film 159Rf, an inorganic film (for example, a silicon nitride film) formed by using a sputtering method can be used.

[0418] Subsequently, as shown in FIG. 9(A), a resist mask 190R is formed on the mask film 159Rf. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and performing exposure and development.

[0419] The resist mask 190R may be fabricated using either a positive resist material or a negative resist material.

[0420] The resist mask 190R is provided at a position overlapping with the conductive layer 152R. It is preferable to also provide the resist mask 190R at a position overlapping with the conductive layer 152C. Thereby, it is possible to suppress the conductive layer 152C from being damaged during the manufacturing process of the display device. Note that it is not necessary to provide the resist mask 190R on the conductive layer 152C. Further, as shown in the cross-sectional view between B1 - B2 in FIG. 9(A), the resist mask 190R is preferably provided so as to cover from the end of the organic compound film 103Rf to the end of the conductive layer 152C (the end on the organic compound film 103Rf side).

[0421] Subsequently, as shown in FIG. 9(B), using the resist mask 190R, a part of the mask film 159Rf is removed to form the mask layer 159R. The mask layer 159R remains on the conductive layer 152R and on the conductive layer 152C. Thereafter, the resist mask 190R is removed. Subsequently, using the mask layer 159R as a mask (also referred to as a hard mask), a part of the sacrificial film 158Rf is removed to form the sacrificial layer 158R.

[0422] The sacrificial film 158Rf and the mask film 159Rf can each be processed by a wet etching method or a dry etching method. The processing of the sacrificial film 158Rf and the mask film 159Rf is preferably performed by isotropic etching.

[0423] By using the wet etching method, the damage applied to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced as compared with the case of using the dry etching method. When using the wet etching method, for example, it is preferable to use a chemical solution using a developer, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed liquid thereof.

[0424] In the processing of the mask film 159Rf, since the organic compound film 103Rf is not exposed, the range of selection of the processing method is wider than that of the processing of the sacrificial film 158Rf. Specifically, when oxygen-containing gas is used as the etching gas during the processing of the mask film 159Rf, the deterioration of the organic compound film 103Rf can be more effectively suppressed.

[0425] Also, when the dry etching method is used in the processing of the sacrificial film 158Rf, the deterioration of the organic compound film 103Rf can be suppressed by not using oxygen-containing gas as the etching gas. When the dry etching method is used, for example, it is preferable to use a gas containing a Group 18 element such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He as the etching gas.

[0426] For example, when an aluminum oxide film formed by ALD method is used as the sacrificial film 158Rf, a part of the sacrificial film 158Rf can be removed by dry etching method using CHF3 and He, or CHF3, He and CH4. Also, when an In-Ga-Zn oxide film formed by sputtering method is used as the mask film 159Rf, a part of the mask film 159Rf can be removed by wet etching method using diluted phosphoric acid. Or, a part of the mask film 159Rf may be removed by dry etching method using CH4 and Ar. Or, a part of the mask film 159Rf can be removed by wet etching method using diluted phosphoric acid. Also, when a tungsten film formed by sputtering method is used as the mask film 159Rf, a part of the mask film 159Rf can be removed by dry etching method using SF6, CF4 and O2, or CF4, Cl2 and O2.

[0427] The resist mask 190R can be removed in the same manner as the resist mask 191. For example, it can be removed by ashing using oxygen plasma. Alternatively, oxygen gas and a Group 18 element such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or He may be used. Alternatively, the resist mask 190R may be removed by wet etching. At this time, since the sacrificial film 158Rf is located on the outermost surface and the organic compound film 103Rf is not exposed, damage to the organic compound film 103Rf can be suppressed in the process of removing the resist mask 190R. In addition, the range of selection of the method for removing the resist mask 190R can be widened.

[0428] Subsequently, as shown in FIG. 9(B), the organic compound film 103Rf is processed to form the organic compound layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove a part of the organic compound film 103Rf to form the organic compound layer 103R.

[0429] As a result, as shown in FIG. 9(B), a stacked structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. In addition, the conductive layer 152G and the conductive layer 152B are exposed.

[0430] FIG. 9(B) shows an example in which the end of the organic compound layer 103R is located inside the end of the conductive layer 152R. With such a configuration, pixel miniaturization is possible, and a high-definition display can be created. Although not shown in FIG. 9(B), depending on the above etching process, recesses may be formed in a region that does not overlap with the organic compound layer 103R of the insulating layer 175.

[0431] As described above, it is preferable that the resist mask 190R is provided so as to cover from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side) between the dashed-dotted lines B1 - B2. Thereby, as shown in FIG. 9(B), the sacrificial layer 158R and the mask layer 159R are provided so as to cover from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side) between the dashed-dotted lines B1 - B2. Therefore, for example, it is possible to suppress the exposure of the insulating layer 175 between the dashed-dotted lines B1 - B2. Thereby, it is possible to prevent a part of the insulating layer 175, the insulating layer 174, and the insulating layer 173 from being removed by etching or the like and the conductive layer 179 from being exposed. For this reason, it is possible to suppress the conductive layer 179 from being unintentionally electrically connected to another conductive layer. For example, it is possible to suppress a short circuit between the conductive layer 179 and the common electrode 155 formed in a later process.

[0432] The processing of the organic compound film 103Rf is preferably performed by anisotropic etching. In particular, anisotropic dry etching is preferable. Alternatively, wet etching may be used.

[0433] When using the dry etching method, by not using a gas containing oxygen as the etching gas, deterioration of the organic compound film 103Rf can be suppressed.

[0434] Also, a gas containing oxygen may be used as the etching gas. By the etching gas containing oxygen, the etching rate can be increased. Therefore, etching can be performed under low-power conditions while maintaining the etching rate at a sufficient speed. For this reason, damage to the organic compound film 103Rf can be suppressed. Furthermore, problems such as adhesion of reaction products generated during etching can be suppressed.

[0435] When using a dry etching method, for example, it is preferable to use, as an etching gas, a gas containing one or more of H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or Group 18 elements such as He and Ar. Alternatively, it is preferable to use, as an etching gas, one or more of these and a gas containing oxygen. Alternatively, oxygen gas may be used as the etching gas. Specifically, for example, a gas containing H2 and Ar, or a gas containing CF4 and He can be used as the etching gas. Also, for example, a gas containing CF4, He, and oxygen can be used as the etching gas. Also, for example, a gas containing H2 and Ar and a gas containing oxygen can be used as the etching gas.

[0436] As described above, in one aspect of the present invention, a resist mask 190R is formed on a mask film 159Rf, and a part of the mask film 159Rf is removed using the resist mask 190R to form a mask layer 159R. Thereafter, a part of the organic compound film 103Rf is removed using the mask layer 159R as a hard mask to form an organic compound layer 103R. Thus, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using a lithography method. Note that a part of the organic compound film 103Rf may be removed using the resist mask 190R. Thereafter, the resist mask 190R may be removed.

[0437] Next, for example, it is preferable to perform a hydrophobization treatment on the conductive layer 152G. When processing the organic compound film 103Rf, for example, the surface state of the conductive layer 152G may change to hydrophilic. By performing a hydrophobization treatment on the conductive layer 152G, for example, the adhesion between the conductive layer 152G and a layer formed in a subsequent step (here, the organic compound layer 103G) can be enhanced, and film peeling can be suppressed. Note that the hydrophobization treatment may not be performed.

[0438] Subsequently, as shown in FIG. 10(A), an organic compound film 103Gf, which will later become the organic compound layer 103G, is formed on the conductive layer 152G, on the conductive layer 152B, on the insulating layer 156R, on the insulating layer 156G, on the insulating layer 156B, on the mask layer 159R, and on the insulating layer 175.

[0439] The organic compound film 103Gf can be formed by the same method as that used for forming the organic compound film 103Rf. Also, the organic compound film 103Gf can have the same configuration as the organic compound film 103Rf.

[0440] Subsequently, as shown in FIG. 10(A), a sacrificial film 158Gf, which will later become the sacrificial layer 158G, and a mask film 159Gf, which will later become the mask layer 159G, are sequentially formed on the organic compound film 103Gf and on the mask layer 159R. Thereafter, a resist mask 190G is formed. The materials and formation method of the sacrificial film 158Gf and the mask film 159Gf are the same as the conditions applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation method of the resist mask 190G are the same as the conditions applicable to the resist mask 190R.

[0441] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0442] Subsequently, as shown in FIG. 10(B), using the resist mask 190G, a part of the mask film 159Gf is removed to form the mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Thereafter, the resist mask 190G is removed. Subsequently, using the mask layer 159G as a mask, a part of the sacrificial film 158Gf is removed to form the sacrificial layer 158G. Subsequently, the organic compound film 103Gf is processed to form the organic compound layer 103G. For example, using the mask layer 159G and the sacrificial layer 158G as hard masks, a part of the organic compound film 103Gf is removed to form the organic compound layer 103G.

[0443] As a result, as shown in FIG. 10(B), a laminated structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G. Also, the mask layer 159R and the conductive layer 152B are exposed.

[0444] Next, for example, it is preferable to perform a hydrophobization treatment on the conductive layer 152B. When processing the organic compound film 103Gf, for example, the surface state of the conductive layer 152B may change to hydrophilic. By performing a hydrophobization treatment on the conductive layer 152B, for example, the adhesion between the conductive layer 152B and a layer formed in a subsequent process (here, the organic compound layer 103B) can be enhanced, and film peeling can be suppressed. Note that the hydrophobization treatment may not be performed.

[0445] Subsequently, as shown in FIG. 10(C), an organic compound film 103Bf that will later become the organic compound layer 103B is formed on the conductive layer 152B, on the mask layer 159R, on the insulating layer 156R, on the insulating layer 156G, on the insulating layer 156B, on the mask layer 159G, and on the insulating layer 175.

[0446] The organic compound film 103Bf can be formed by the same method as the method used to form the organic compound film 103Rf. Also, the organic compound film 103Bf can have the same configuration as the organic compound film 103Rf.

[0447] Subsequently, as shown in FIG. 10(C), a sacrificial film 158Bf that will later become the sacrificial layer 158B and a mask film 159Bf that will later become the mask layer 159B are sequentially formed on the organic compound film 103Bf and on the mask layer 159R. Thereafter, a resist mask 190B is formed. The materials and formation methods of the sacrificial film 158Bf and the mask film 159Bf are the same as the conditions applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the resist mask 190B are the same as the conditions applicable to the resist mask 190R.

[0448] The resist mask 190B is provided at a position overlapping the conductive layer 152B.

[0449] Subsequently, as shown in FIG. 10(D), using the resist mask 190B, a part of the mask film 159Bf is removed to form the mask layer 159B. The mask layer 159B remains on the conductive layer 152B. Thereafter, the resist mask 190B is removed. Subsequently, using the mask layer 159B as a mask, a part of the sacrificial film 158Bf is removed to form the sacrificial layer 158B. Subsequently, the organic compound film 103Bf is processed to form the organic compound layer 103B. For example, using the mask layer 159B and the sacrificial layer 158B as hard masks, a part of the organic compound film 103Bf is removed to form the organic compound layer 103B.

[0450] As a result, as shown in FIG. 10(D), a stacked structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. Also, the mask layer 159R and the mask layer 159G are exposed.

[0451] Note that the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are preferably perpendicular or substantially perpendicular to the formation surface. For example, the angle formed by the formation surface and these side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0452] As described above, the distance between two adjacent ones of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B formed by using the lithography method can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, the distance can be defined, for example, as the distance between two opposing end portions of two adjacent ones among the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By narrowing the distance between the island-shaped organic compound layers in this way, a display device having high definition and a large aperture ratio can be provided. Also, the distance between the first electrodes between adjacent light-emitting devices can also be narrowed and can be, for example, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less. Note that the distance between the first electrodes between adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0453] Subsequently, as shown in FIG. 11(A), it is preferable to remove the mask layer 159R, the mask layer 159G, and the mask layer 159B. Depending on subsequent processes, the sacrificial layer 158R, the sacrificial layer 158G, the sacrificial layer 158B, the mask layer 159R, the mask layer 159G, and the mask layer 159B may remain in the display device. By removing the mask layer 159R, the mask layer 159G, and the mask layer 159B at this stage, it is possible to suppress the remaining of the mask layer 159R, the mask layer 159G, and the mask layer 159B in the display device. For example, when a conductive material is used for the mask layer 159R, the mask layer 159G, and the mask layer 159B, by removing the mask layer 159R, the mask layer 159G, and the mask layer 159B in advance, it is possible to suppress the generation of leakage current and the formation of capacitance due to the remaining mask layer 159R, the mask layer 159G, and the mask layer 159B.

[0454] In this embodiment, the case of removing the mask layer 159R, the mask layer 159G, and the mask layer 159B is taken as an example for explanation, but the mask layer 159R, the mask layer 159G, and the mask layer 159B may not be removed. For example, when the mask layer 159R, the mask layer 159G, and the mask layer 159B contain a material having light-shielding properties with respect to ultraviolet rays as described above, it is preferable to proceed to the next step without removing them, so that the organic compound layer can be protected from ultraviolet rays.

[0455] For the mask layer removal process, the same method as the mask film processing process can be used. In particular, by using the wet etching method, compared with the case of using the dry etching method, when removing the mask layer, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced.

[0456] Alternatively, the mask layer may be removed by dissolving it in a solvent such as water or alcohol. Examples of alcohol include ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0457] After removing the mask layer, a drying process may be performed to remove the water contained in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, as well as the water adsorbed on the surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. For example, heat treatment can be performed under an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be carried out at a temperature of 50°C or higher and 200°C or lower as the substrate temperature, preferably 60°C or higher and 150°C or lower, more preferably 70°C or higher and 120°C or lower. Making it a reduced pressure atmosphere is preferable because drying can be performed at a lower temperature.

[0458] Subsequently, as shown in FIG. 11(B), an inorganic insulating film 125f that will later become the inorganic insulating layer 125 is formed so as to cover the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B.

[0459] As will be described later, an insulating film that will later become the insulating layer 127 is formed in contact with the upper surface of the inorganic insulating film 125f. For this reason, it is preferable that the upper surface of the inorganic insulating film 125f has high affinity for the material used for the insulating film (for example, a photosensitive resin composition containing an acrylic resin). In order to improve the affinity, it is preferable to perform surface treatment to hydrophobize (or increase the hydrophobicity of) the upper surface of the inorganic insulating film 125f. For example, it is preferable to perform treatment using a silylating agent such as hexamethyldisilazane (HMDS). By hydrophobizing the upper surface of the inorganic insulating film 125f in this way, the insulating film 127f can be formed with good adhesion. Note that, as the surface treatment, the above-described hydrophobization treatment may be performed.

[0460] Subsequently, as shown in FIG. 11(C), an insulating film 127f that will later become the insulating layer 127 is formed on the inorganic insulating film 125f.

[0461] The inorganic insulating film 125f and the insulating film 127f are preferably formed by a formation method that causes little damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In particular, since the inorganic insulating film 125f is formed in contact with the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, it is preferably formed by a formation method that causes less damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B than the insulating film 127f.

[0462] Also, the inorganic insulating film 125f and the insulating film 127f are each formed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. Also, by increasing the substrate temperature during the formation of the inorganic insulating film 125f, even if the film thickness is thin, a film with a low impurity concentration and high barrier properties against at least one of water and oxygen can be obtained.

[0463] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0464] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm or more, 5 nm or more, or 10 nm or more, and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above range of the substrate temperature.

[0465] The inorganic insulating film 125f is preferably formed using, for example, the ALD method. Using the ALD method is preferable because film formation damage can be reduced and a film with high coverage can be formed. As the inorganic insulating film 125f, it is preferable to form an aluminum oxide film using, for example, the ALD method.

[0466] In addition, the inorganic insulating film 125f may be formed using a sputtering method, a CVD method, or a PECVD method, which have a higher film formation rate than the ALD method. Thereby, a highly reliable display device can be manufactured with high productivity.

[0467] The insulating film 127f is preferably formed using the above-described wet film formation method. The insulating film 127f is preferably formed, for example, by spin coating using a photosensitive material, and more specifically, is preferably formed using a photosensitive resin composition containing an acrylic resin.

[0468] The insulating film 127f is preferably formed using, for example, a resin composition having a polymer, an acid generator, and a solvent. The polymer is formed using one or more monomers and has a structure in which one or more structural units (also referred to as constituent units) are repeated regularly or irregularly. As the acid generator, one or both of a compound that generates an acid upon irradiation with light and a compound that generates an acid upon heating can be used. The resin composition may further have one or more of a photosensitizer, a sensitizer, a catalyst, an adhesion aid, a surfactant, and an antioxidant.

[0469] Further, it is preferable to perform a heat treatment (also referred to as a pre-bake) after the formation of the insulating film 127f. The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. The substrate temperature during the heat treatment is preferably 50°C or higher and 200°C or lower, more preferably 60°C or higher and 150°C or lower, and even more preferably 70°C or higher and 120°C or lower. Thereby, the solvent contained in the insulating film 127f can be removed.

[0470] Subsequently, exposure is performed to make a part of the insulating film 127f sensitive to visible light or ultraviolet light. Here, when a positive photosensitive resin composition containing an acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the regions where the insulating layer 127 will not be formed in later processes. The insulating layer 127 is formed in the region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated onto the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C. Note that when a negative photosensitive material is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the regions where the insulating layer 127 will be formed.

[0471] The width of the insulating layer 127 to be formed later can be controlled by the exposure region on the insulating film 127f. In the present embodiment, processing is performed such that the insulating layer 127 has a portion overlapping with the upper surface of the conductive layer 151.

[0472] The light used for exposure preferably includes i-line (wavelength 365 nm). Further, the light used for exposure may include at least one of g-line (wavelength 436 nm) and h-line (wavelength 405 nm).

[0473] Here, by providing an oxygen barrier insulating layer (for example, an aluminum oxide film, etc.) as one or both of the sacrificial layer 158 (sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B) and the inorganic insulating film 125f, the diffusion of oxygen into the organic compound layers 103R, 103G, and 103B can be reduced. When the organic compound layer is irradiated with light (visible light or ultraviolet light), the organic compound contained in the organic compound layer may be excited, and the reaction with oxygen contained in the atmosphere may be promoted. More specifically, in an atmosphere containing oxygen, when the organic compound layer is irradiated with light (visible light or ultraviolet light), oxygen may bind to the organic compound contained in the organic compound layer. By providing the sacrificial layer 158 and the inorganic insulating film 125f on the island-shaped organic compound layer, the binding of oxygen in the atmosphere to the organic compound contained in the organic compound layer can be reduced.

[0474] Subsequently, as shown in FIG. 12(A), development is performed to remove the exposed area of the insulating film 127f and form the insulating layer 127a. The insulating layer 127a is formed in an area sandwiched between any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B, and in an area surrounding the conductive layer 152C. Here, when an acrylic resin is used for the insulating film 127f, an alkaline solution can be used as the developer, for example, TMAH can be used.

[0475] Subsequently, residues (so-called scum) during development may be removed. For example, the residues can be removed by performing ashing using oxygen plasma.

[0476] Note that etching may be performed to adjust the height of the surface of the insulating layer 127a. The insulating layer 127a may be processed, for example, by ashing using oxygen plasma. Also, even when a non-photosensitive material is used for the insulating film 127f, the height of the surface of the insulating film 127f can be adjusted, for example, by the ashing.

[0477] Subsequently, as shown in FIG. 12(B), an etching process is performed using the insulating layer 127a as a mask to remove a part of the inorganic insulating film 125f and reduce the film thickness of a part of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, an inorganic insulating layer 125 is formed under the insulating layer 127a. Also, the surfaces of the thin portions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are exposed. Hereinafter, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0478] The first etching process can be performed by dry etching or wet etching. Note that when the inorganic insulating film 125f is formed using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is preferable because the first etching process can be performed in a batch.

[0479] By performing etching using the insulating layer 127a with a tapered side surface as a mask, the side surfaces of the inorganic insulating layer 125 and the upper ends of the side surfaces of the sacrificial layers 158R, 158G, and 158B can be made into a tapered shape relatively easily.

[0480] When performing dry etching, it is preferable to use a chlorine-based gas. As the chlorine-based gas, Cl2, BCl3, SiCl4, CCl4, etc. can be used alone or in combination of two or more gases. Further, oxygen gas, hydrogen gas, helium gas, argon gas, etc. can be appropriately added to the above chlorine-based gas alone or in combination of two or more gases. By using dry etching, regions with a thin film thickness of the sacrificial layers 158R, 158G, and 158B can be formed with good in-plane uniformity.

[0481] As the dry etching apparatus, a dry etching apparatus having a high-density plasma source can be used. As the dry etching apparatus having a high-density plasma source, for example, an inductively coupled plasma (ICP) etching apparatus can be used. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes can be used. The capacitively coupled plasma etching apparatus having parallel plate electrodes may be configured to apply a high-frequency voltage to one of the parallel plate electrodes. Alternatively, it may be configured to apply a plurality of different high-frequency voltages to one of the parallel plate electrodes. Alternatively, it may be configured to apply a high-frequency voltage of the same frequency to each of the parallel plate electrodes. Alternatively, it may be configured to apply high-frequency voltages of different frequencies to each of the parallel plate electrodes.

[0482] Further, when performing dry etching, by-products generated by the dry etching may deposit on the upper surface and side surfaces of the insulating layer 127a, etc. For this reason, components contained in the etching gas, components contained in the inorganic insulating film 125f, components contained in the sacrificial layers 158R, 158G, and 158B, etc. may be contained in the insulating layer 127 after the display device is completed.

[0483] Also, it is preferable to perform the first etching process by wet etching. By using the wet etching method, damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to the case of using the dry etching method. For example, wet etching can be performed using an alkaline solution. For example, TMAH, which is an alkaline solution, can be used for wet etching of an aluminum oxide film. In this case, wet etching can be performed by the paddle method. In addition, when the inorganic insulating film 125f is formed using the same materials as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is preferable because the above etching process can be performed collectively.

[0484] In the first etching process, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are not completely removed, and the etching process is stopped in a state where the film thickness is reduced. In this way, by leaving the corresponding sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B on the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, it is possible to prevent the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B from being damaged in the subsequent process.

[0485] Subsequently, it is preferable to expose the entire substrate and irradiate the insulating layer 127a with visible light or ultraviolet light. The energy density of the exposure is preferably greater than 0 mJ / cm 2 and less than or equal to 800 mJ / cm 2 more preferably greater than 0 mJ / cm 2 and less than or equal to 500 mJ / cm 2 Performing such exposure after development may improve the transparency of the insulating layer 127a. Also, in some cases, the substrate temperature required for the heat treatment to deform the insulating layer 127a into a tapered shape in a subsequent process can be reduced.

[0486] Here, as the sacrificial layers 158R, 158G, and 158B, the presence of a barrier insulating layer against oxygen (e.g., an aluminum oxide film or the like) can reduce the diffusion of oxygen into the organic compound layers 103R, 103G, and 103B. When the organic compound layer is irradiated with light (visible light or ultraviolet light), the organic compounds contained in the organic compound layer may be excited, and the reaction with oxygen contained in the atmosphere may be promoted. More specifically, in an atmosphere containing oxygen, when the organic compound layer is irradiated with light (visible light or ultraviolet light), oxygen may bind to the organic compounds contained in the organic compound layer. By providing the sacrificial layers 158R, 158G, and 158B on the island-shaped organic compound layer, it is possible to reduce the binding of oxygen in the atmosphere to the organic compounds contained in the organic compound layer.

[0487] Subsequently, a heat treatment (also referred to as post-bake) is performed. By performing the heat treatment, the insulating layer 127a can be deformed into an insulating layer 127 having a tapered shape on the side surface (FIG. 12(C)). The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, more preferably 70°C or higher and 130°C or lower. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. Also, the heating atmosphere may be an atmospheric pressure atmosphere or a reduced pressure atmosphere. It is preferable to increase the substrate temperature in the heat treatment of this step compared to the heat treatment (pre-bake) after the formation of the insulating film 127f. Thereby, the adhesion between the insulating layer 127 and the inorganic insulating layer 125 can be improved, and the corrosion resistance of the insulating layer 127 can also be improved.

[0488] In the first etching process, instead of completely removing the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B with reduced film thickness are left remaining. By doing so, in the heat treatment, it is possible to prevent the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B from being damaged and deteriorated. Therefore, the reliability of the light-emitting device can be enhanced.

[0489] Note that depending on the material of the insulating layer 127 and the temperature, time, and atmosphere of the post-bake, a concave curved surface shape may be formed on the side surface of the insulating layer 127. For example, under the post-bake conditions, the higher the temperature or the longer the time, the more likely the shape of the insulating layer 127 is to change, and a concave curved surface shape may be formed.

[0490] Subsequently, as shown in FIG. 13(A), using the insulating layer 127 as a mask, an etching process is performed to remove a part of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. Note that a part of the inorganic insulating layer 125 may also be removed. Thereby, openings are formed in each of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Note that hereinafter, the etching process using the insulating layer 127 as a mask may be referred to as the second etching process.

[0491] The end portion of the inorganic insulating layer 125 is covered with the insulating layer 127. Further, FIG. 13(A) shows an example in which the insulating layer 127 covers a part of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process), and the tapered portion formed by the second etching process is exposed.

[0492] If the first etching process is not performed and the inorganic insulating layer 125 and the mask layer are etched all at once after post-baking, side etching may cause the inorganic insulating layer 125 and the mask layer under the end of the insulating layer 127 to disappear, forming a cavity. Due to this cavity, unevenness occurs on the surface where the common electrode 155 is formed, and the common electrode 155 is likely to have steps. Even if the inorganic insulating layer 125 and the mask layer are side-etched in the first etching process to form a cavity, the insulating layer 127 can fill the cavity by performing post-baking thereafter. Then, in the second etching process, since the mask layer with a smaller thickness is etched, the amount of side etching is small, and it is difficult to form a cavity. Even if a cavity is formed, it can be made extremely small. Therefore, the surface on which the common electrode 155 is formed can be made flatter.

[0493] Note that the insulating layer 127 may cover the entire end of the sacrificial layer 158G. For example, the end of the insulating layer 127 may sag and cover the end of the sacrificial layer 158G. Also, for example, the end of the insulating layer 127 may be in contact with the upper surface of at least one of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. As described above, when the exposed insulating layer 127a after development is not exposed, the shape of the insulating layer 127 may easily change.

[0494] The second etching process is performed by wet etching. By using the wet etching method, the damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to the case of using the dry etching method. Wet etching can be performed using an alkaline solution such as TMAH, for example.

[0495] On the other hand, when performing the second etching process using a wet etching method, for example, due to the problem of adhesion between the organic compound layer 103 and other layers, if there are gaps between the organic compound layer 103 and the sacrificial layer 158, between the organic compound layer 103 and the inorganic insulating layer 125, and at the interface between the organic compound layer 103 and the insulating layer 175, the chemical solution used in the second etching process may penetrate into the gaps, and the chemical solution may come into contact with the pixel electrode. Here, when the chemical solution comes into contact with both the conductive layer 151 and the conductive layer 152, the conductive layer with a lower natural potential among the conductive layer 151 and the conductive layer 152 may be corroded by galvanic corrosion. For example, when aluminum is used as the conductive layer 151 and indium tin oxide is used as the conductive layer 152, the conductive layer 152 may be corroded. From the above, the yield of the display device may decrease. Also, the reliability of the display device may decrease.

[0496] As described above, by forming the insulating layer 156 so as to have a region overlapping the side surface of the conductive layer 151 and forming the insulating layer 156 so as to cover the conductive layer 151 and the conductive layer 152, it is possible to prevent the step break of the inorganic insulating layer 125. Therefore, for example, in the second etching process, it is possible to prevent the chemical solution from coming into contact with the underlying structure such as the conductive layer 151. Thereby, corrosion of the pixel electrode can be prevented.

[0497] As described above, by providing the insulating layer 127, the inorganic insulating layer 125, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is possible to suppress the occurrence of connection failures due to the disconnected portions and the increase in electrical resistance due to the locally thin film thickness portions in the common electrode 155 between the respective light-emitting devices. Thereby, the display device according to one aspect of the present invention can improve the display quality.

[0498] Further, after exposing a part of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, a heat treatment is further performed. By this heat treatment, water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, etc. can be removed. Also, the shape of the insulating layer 127 may change due to this heat treatment. Specifically, the insulating layer 127 may spread so as to cover at least one of the end portions of the inorganic insulating layer 125, the end portions of the sacrificial layers 158R, 158G, and 158B, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B.

[0499] If the temperature of the heat treatment is too low, water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, etc. cannot be sufficiently removed. Also, if the temperature of the heat treatment is too high, deterioration of the organic compound layer 103 and excessive change in the shape of the insulating layer 127 may occur. Therefore, the heat treatment preferably has a temperature higher than the temperature at which water desorbs from the organic compound layer 103 and lower than the glass transition temperature of the organic compound contained in the organic compound layer 103, and preferably lower than the glass transition temperature of the organic compound contained on the upper surface of the organic compound layer 103. Specifically, it is preferably performed at a substrate temperature of 80°C or higher and 130°C or lower, more preferably 90°C or higher and 120°C or lower, still more preferably 100°C or higher and 120°C or lower, and even more preferably 100°C or higher and 110°C or lower. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. Also, the heating atmosphere may be an atmospheric pressure atmosphere or a reduced pressure atmosphere, but a reduced pressure atmosphere is preferred so that the water desorbed from the organic compound layer 103 does not re-adsorb.

[0500] By this heat treatment, water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, etc. can be sufficiently removed without causing deterioration of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B and excessive change in the shape of the insulating layer 127. Thereby, a decrease in the characteristics of the light-emitting device can be prevented.

[0501] Subsequently, as shown in FIG. 13(B), a common layer 104 and a common electrode 155 are formed on the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the conductive layer 152C, and the insulating layer 127. The common layer 104 and the common electrode 155 can be formed by methods such as sputtering or vacuum evaporation. The common layer 104 may be formed by evaporation and the common electrode 155 may be formed by sputtering.

[0502] Subsequently, as shown in FIG. 13(C), a protective layer 131 is formed on the common electrode 155. The protective layer 131 can be formed by methods such as vacuum evaporation, sputtering, CVD, or ALD.

[0503] Subsequently, the display device can be manufactured by bonding the substrate 120 onto the protective layer 131 using the resin layer 122. As described above, in the method for manufacturing a display device according to an aspect of the present invention, the insulating layer 156 is provided on the side surfaces of the conductive layer 151 and the conductive layer 152. Thereby, the yield of the display device can be increased and the occurrence of defects can be suppressed.

[0504] As described above, in the method for manufacturing a display device according to an aspect of the present invention, the island-shaped organic compound layer 103R, the island-shaped organic compound layer 103G, and the island-shaped organic compound layer 103B are not formed using a fine metal mask, but are formed by processing after forming a film on one surface. Therefore, the island-shaped layers can be formed with a uniform thickness. Then, a high-definition display device or a display device with a high aperture ratio can be realized. Also, even when the fineness or aperture ratio is high and the distance between adjacent sub-pixels is extremely short, it is possible to suppress the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B from contacting each oth...

Claims

1. A light-emitting device having a first electrode, a second electrode, and an organic compound layer, wherein the organic compound layer is located between the first electrode and the second electrode, the organic compound layer has a light-emitting layer and an electron injection layer, the electron injection layer contains a metal or metal oxide, a first organic compound, and a second organic compound, the first organic compound has a π-electron deficient heteroaromatic ring, the second organic compound has two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and have a total of three or more heteroatoms, and the second organic compound has a function of interacting with the metal or the metal compound in a multidentate manner through two or more of the three or more heteroatoms.

2. A first electrode group formed on the same insulating surface, a second electrode facing the first electrode group, and a first layer group located between the first electrode group and the second electrode, and the light-emitting device is one of a plurality of light-emitting devices included in a light-emitting device group, wherein the light-emitting device has a first electrode, the second electrode, and a first layer, the first electrode is one of the first electrode group, the first electrode is independent for each of the plurality of light-emitting devices, the first layer is one of the first layer group, the first layer is independent for each of the plurality of light-emitting devices, the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, the second electrode and the first layer overlap the first electrode, the first layer has a light-emitting layer and an electron injection layer, the electron injection layer contains a metal or metal oxide, a first organic compound, and a second organic compound, the first organic compound has a π-electron deficient heteroaromatic ring, the second organic compound has two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and have a total of three or more heteroatoms, the second organic compound has a function of interacting with the metal or the metal compound in a multidentate manner through two or more of the three or more heteroatoms, and the distance between the first layer of the light-emitting device and the first layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

3. The light-emitting device according to claim 1 or claim 2, wherein the second organic compound has a function of interacting with the metal or the metal compound at a bidentate or tridentate position by the heteroatom.

4. The light-emitting device according to claim 1 or claim 2, wherein the heteroatom is a nitrogen atom.

5. A light-emitting device comprising a first electrode, a second electrode, and an organic compound layer, wherein the organic compound layer is located between the first electrode and the second electrode, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer includes a metal or metal oxide, a first organic compound, and a second organic compound, the first organic compound has a π-electron-deficient heteroaromatic ring, and the second organic compound is an organic compound represented by the general formula (G1-1). 【Chemical 1】 (In general formula (G1-1), A １ , A ２ and A ３ each independently represents a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, and A １ , A ２ and A ３ may form a condensed ring with each other.)

6. A light-emitting device comprising a first electrode, a second electrode, and an organic compound layer, wherein the organic compound layer is located between the first electrode and the second electrode, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer includes a metal or metal oxide, a first organic compound, and a second organic compound, the first organic compound has a π-electron-deficient heteroaromatic ring, and the second organic compound is an organic compound represented by the general formula (G1-2). [Chemical Formula 2] (In general formula (G1-2), A １ , and A ２ each independently represent a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms, and A １ , and A ２ may form a condensed ring with each other, and A １ has two or more nitrogen atoms.)

7. The light-emitting device according to any one of claims 1, 2, 5, and 6, wherein the heteroaromatic ring is a π-electron-deficient heteroaromatic ring.

8. The light-emitting device according to any one of claims 1, 2, 5, and 6, wherein the heteroaromatic ring includes at least one of a pyridine ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), a triazine ring, an azole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), and a triazole ring.

9. The light-emitting device according to any one of claims 1, 2, 5, and 6, wherein at least one of two or more of the heteroaromatic rings includes a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring.

10. The light-emitting device according to any one of claims 1, 2, 5, and 6, wherein two or more of the heteroaromatic rings include a total of three or more pyridine rings.

11. In any one of claims 1, 2, 5, and 6, The first organic compound has an electron-donating group, a light-emitting device.

12. In claim 11, The electron-donating group is at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group, a light-emitting device.

13. In any one of claim 1, claim 2, claim 5, and claim 6, The first organic compound has an acid dissociation constant pKa of 8 or more, a light-emitting device.

14. In any one of claim 1, claim 2, claim 5, and claim 6, The first organic compound has a phenanthroline ring, a light-emitting device.

15. In any one of claim 1, claim 2, claim 5, and claim 6, The second organic compound has a glass transition temperature T ｇ of 100°C or higher, and is a light-emitting device.

16. In any one of claim 1, claim 2, claim 5, and claim 6, The LUMO level of the second organic compound is lower than the LUMO level of the first organic compound, a light-emitting device.

17. In any one of claim 1, claim 2, claim 5, and claim 6, The metal belongs to Group 1, Group 3, Group 11, or Group 13 in the periodic table, a light-emitting device.

18. In any one of claim 1, claim 2, claim 5, and claim 6, The first layer is a mixture of the metal, the second organic compound, and the first organic compound, a light-emitting device.

19. In any one of claim 1, claim 2, claim 5, and claim 6, The first layer is a laminate of a layer containing the metal and a layer containing the second organic compound or the first organic compound, a light-emitting device.

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