Light emitting device

Abstract

A light emitting device driven at a low voltage is provided. The light-emitting device comprises 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 comprises a light-emitting layer and an electron injection layer, and the electron injection layer comprises metal or metal oxide, a first organic compound and a second organic compound. The first organic compound includes a pi-electron-deficient heteroaromatic ring, and the second organic compound includes two or more heteroaromatic rings which are bonded or fused to each other and include three or more heteroatoms in total. The second organic compound has a function in which two or more of three or more heteroatoms interact with a metal or a metal oxide as a polydentate ligand.

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. As an example of the technical field of one aspect of the present invention, 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), and driving methods or manufacturing methods of the above devices can be cited. Background Art

[0003] In recent years, display devices have been applied to various uses. For example, as uses of large display devices, research and development have been carried out on home television devices (also referred to as TVs or television receivers), digital signage, and public information displays (PIDs: Public Information Display), etc., and as uses of small display devices, research and development have been carried out on smartphones or tablet terminals equipped with touch panels, etc.

[0004] At the same time, high definition of display devices is also being carried out. As devices that require high-definition display devices, for example, research and development have been carried out on devices for virtual reality (VR: Virtual Reality), augmented reality (AR: Augmented Reality), substitutional reality (SR: Substitutional Reality), and mixed reality (MR: Mixed Reality).

[0005] As a display element for a display device, the development of a light-emitting device (also referred to as a light-emitting element) is becoming increasingly popular. A light-emitting device (also referred to as an EL device or an EL element) that utilizes the electroluminescence (hereinafter referred to as EL) phenomenon, particularly an organic EL device mainly using organic compounds, has the following characteristics: it is easy to achieve thin and lightweight; it can respond to input signals at high speed; and it can be driven using a DC constant voltage power supply, etc., and thus it is preferably applied to a display device.

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

[0007] [Patent Document 1] Japanese PCT International Application Translation No. 2018-521459 Gazette Summary of the Invention

[0008] In previously known organic EL devices (also referred to as light-emitting devices in this specification), the initial characteristics and reliability of the EL layer are affected when exposed to atmospheric components such as water and oxygen, and the EL layer is processed in an atmosphere close to vacuum in common sense steps. In particular, the electron injection layer uses an alkali metal or an alkaline earth metal or a compound thereof, and these metals and compounds have a very high reactivity with water or oxygen. When the surface of the EL layer is exposed to the atmosphere, the electron injection layer rapidly deteriorates and loses its function as an electron injection layer.

[0009] However, in the above process of processing by photolithography, it is inevitable to expose the surface of the EL layer to the atmosphere.

[0010] One of the objects of one aspect of the present invention is to provide a novel light-emitting device. Another object of one aspect of the present invention is to provide a light-emitting device having good efficiency. Another object of one aspect of the present invention is to provide a light-emitting device having good reliability. Another object of one aspect of the present invention is to provide a light-emitting device having good efficiency and reliability.

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

[0012] Another object of one aspect of the present invention is to provide a novel light-emitting device applicable to a high-definition display device. Another object of one aspect of the present invention is to provide a light-emitting device having good efficiency applicable to a high-definition display device. Another object of one aspect of the present invention is to provide a light-emitting device having good reliability applicable to a high-definition display device. Another object of one aspect of the present invention is to provide a light-emitting device having good luminous efficiency and reliability applicable to a high-definition display device.

[0013] Another object of one aspect of the present invention is to provide a display device with high reliability. Another object of one aspect of the present invention is to provide a high-definition display device. Another object of one aspect of the present invention is to provide a high-definition and highly reliable display device.

[0014] Note that the description of these objects does not preclude the existence of other objects. One embodiment of the present invention does not need to achieve all of the above objects. Objects other than the above objects can be extracted from the description of the specification, drawings, and claims.

[0015] One embodiment of the present invention is a light-emitting device including: 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 contains a metal or a metal oxide, a first organic compound, and a second organic compound, the first organic compound includes a π-deficient heteroaromatic ring, the second organic compound includes two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and include three or more heteroatoms in total, and the second organic compound has a function of interacting with the metal or the metal oxide as a multidentate ligand by two or more of the three or more heteroatoms.

[0016] One embodiment of the present invention is a light-emitting device which is one of a plurality of light-emitting devices included in a light-emitting device group, the light-emitting device group including: a first electrode group formed on the same insulating surface; a second electrode group opposed to the first electrode group; and a first layer group located between the first electrode group and the second electrode group, the light-emitting device including: a first electrode; a second electrode; and a first layer, wherein 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 includes a light-emitting layer and an electron injection layer, the electron injection layer contains a metal or a metal oxide, a first organic compound, and a second organic compound, the first organic compound includes a π-deficient heteroaromatic ring, the second organic compound includes two or more heteroaromatic rings, the two or more heteroaromatic rings are bonded or fused to each other and include three or more heteroatoms in total, the second organic compound has a function of interacting with the metal or the metal oxide as a multidentate ligand by two or more of the three or more heteroatoms, and the interval between the first layer included in the light-emitting device and the first layer included in other light-emitting devices adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

[0017] In the light-emitting device according to one embodiment of the above invention, the second organic compound has a function of interacting with the metal or the metal oxide as a bidentate ligand or a tridentate ligand by a heteroatom.

[0018] In the light-emitting device according to one embodiment of the above invention, the heteroatom is a nitrogen atom.

[0019] One embodiment of the present invention is a light-emitting device including: 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 contains a metal or a metal oxide, a first organic compound, and a second organic compound, the first organic compound includes a π-deficient heteroaromatic ring, and the second organic compound is an organic compound represented by the general formula (G1-1).

[0020] [Chemical formula 1]

[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 also form a condensed ring.

[0022] One embodiment of the present invention is a light-emitting device including: 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 contains a metal or a metal oxide, a first organic compound, and a second organic compound, the first organic compound includes a π-deficient heteroaromatic ring, and the second organic compound is an organic compound represented by the general formula (G1-2).

[0023] [Chemical formula 2]

[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, A 1 and A 2 may also form a condensed ring, and A 1 contains two or more nitrogen atoms.

[0025] In the light-emitting device according to one embodiment of the above invention, the heteroaromatic ring is a π-deficient heteroaromatic ring.

[0026] In the light-emitting device according to one embodiment of the above invention, 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.

[0027] In a light-emitting device according to one embodiment of the above invention, at least one of two or more heteroaromatic rings includes a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring.

[0028] In a light-emitting device according to one embodiment of the above invention, two or more heteroaromatic rings in total include three or more pyridine rings.

[0029] In a light-emitting device according to one embodiment of the above invention, the first organic compound has an electron-donating group.

[0030] In a light-emitting device according to one embodiment 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.

[0031] In a light-emitting device according to one embodiment of the above invention, the acidity coefficient pK of the first organic compound a is 8 or more.

[0032] In a light-emitting device according to one embodiment of the above invention, the first organic compound includes a phenanthroline ring.

[0033] In a light-emitting device according to one embodiment of the above invention, the glass transition temperature T of the second organic compound g is 100°C or more.

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

[0035] In a light-emitting device according to one embodiment of the above invention, the metal belongs to Group 1, Group 3, Group 11, or Group 13 of the periodic table of the elements.

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

[0037] In a light-emitting device according to one embodiment 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.

[0038] In addition, one embodiment of the present invention is a light-emitting device including a plurality of light-emitting devices. Among them, the plurality of light-emitting devices are respectively any of the above light-emitting devices, and each of the plurality of light-emitting devices includes an organic compound layer, the organic compound layer includes a light-emitting layer and an electron injection layer located between a first electrode and a second electrode, and the EL layers included in each of the plurality of light-emitting devices are independent of each other among the plurality of light-emitting devices.

[0039] In addition, one embodiment of the present invention is a display module including the above light-emitting device and at least one of a connector and an integrated circuit.

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

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

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

[0043] In addition, according to one aspect of the present invention, a novel light-emitting device applicable to a high-definition display device can be provided. In addition, according to one aspect of the present invention, a light-emitting device having good efficiency applicable to a high-definition display device can be provided. In addition, according to one aspect of the present invention, a light-emitting device having good reliability applicable to a high-definition display device can be provided. In addition, according to one aspect of the present invention, a light-emitting device having good luminous efficiency and reliability applicable to a high-definition display device can be provided.

[0044] In addition, according to one aspect of the present invention, a display device with high reliability can be provided. In addition, according to one aspect of the present invention, a high-definition display device can be provided. In addition, according to one aspect of the present invention, a high-definition and highly reliable display device can be provided.

[0045] In addition, according to one aspect of the present invention, 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 all of the above effects. Effects other than the above can be extracted from the description of the specification, the drawings, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1A and Figure 1B is a diagram showing the light-emitting device; Figure 2 is the analysis result of the spin density distribution in the ground state of the composite material; Figure 3 is the analysis result of the electrostatic potential map in the ground state of the composite material; Figure 4A and Figure 4B is a figure showing a light-emitting device; Figure 5A and Figure 5B is a figure showing a light-emitting device; Fig. 6A and Figure 6B are the top view and cross-sectional view of a light-emitting device; FIG. 7A to FIG. 7D is a figure showing a light-emitting device; FIG. 8A to FIG. 8E is a cross-sectional view showing an example of a manufacturing method of a display device; Fig.9A and Fig. 9B is a cross-sectional view showing an example of a manufacturing method of a display device; FIG. 10A to FIG. 10D is a cross-sectional view showing an example of a manufacturing method of a display device; FIG. 11A to FIG. 11C is a cross-sectional view showing an example of a manufacturing method of a display device; FIG. 12A to FIG. 12C is a cross-sectional view showing an example of a manufacturing method of a display device; FIG. 13A to FIG. 13C is a cross-sectional view showing an example of a manufacturing method of a display device; FIG. 14A to FIG. 14G is the top view showing an example of the structure of a pixel; FIG. 15A to FIG. 15I is the top view showing an example of the structure of a pixel; Fig.16A and Fig. 16B is a perspective view showing an example of the structure of a display module; Fig.17A and Fig. 17B is a cross-sectional view showing an example of the structure of a display device; Fig.18 is a perspective view showing an example of the structure of a display device; Fig.19 is a cross-sectional view showing an example of the structure of a display device; Fig. 20 is a cross-sectional view showing an example of the structure of a display device; FIG. 21A to FIG. 21C is a figure showing an example of the structure of a display device; Fig. 22 is a cross-sectional view showing an example of the structure of a display device; FIG. 23A to FIG. 23C is a diagram showing an example of the structure of a display device; FIG. 24A to FIG. 24D is a diagram showing an example of an electronic device; FIG. 25A to FIG. 25F is a diagram showing an example of an electronic device; FIG. 26A to FIG. 26G is a diagram showing an example of an electronic device; Fig. 27 is a diagram illustrating the structure of a light-emitting device; Fig.28 is a diagram illustrating the luminance-current density characteristics of a light-emitting device; Fig.29 is a diagram illustrating the luminance-voltage characteristics of a light-emitting device; Fig.30 is a diagram illustrating the current efficiency-luminance characteristics of a light-emitting device; Fig.31 is a diagram illustrating the current density-voltage characteristics of a light-emitting device; Fig.32 is a diagram illustrating the electroluminescence spectrum of a light-emitting device; Fig.33 is a diagram illustrating the voltage of a light-emitting device with respect to a constant current density; Fig.34 is a diagram showing the ESR measurement results of the sample of this embodiment; Fig.35 is a diagram illustrating the change in luminance of a light-emitting device with respect to the driving time; Fig.36 is a diagram illustrating the luminance-current density characteristics of a light-emitting device; Fig.37 is a diagram illustrating the luminance-voltage characteristics of a light-emitting device; Fig.38 is a diagram illustrating the current efficiency-luminance characteristics of a light-emitting device; Fig.39 is a diagram illustrating the current density-voltage characteristics of a light-emitting device; Fig.40 is a diagram illustrating the electroluminescence spectrum of a light-emitting device; Fig.41 is a diagram illustrating the change in luminance of a light-emitting device with respect to the driving time. Detailed implementation manners

[0048] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and it is easily understandable for those of ordinary skill in the art that its mode and details can be changed into various forms without departing from the gist and scope of the present invention. Therefore, the present invention should not be construed as being limited only to the content described in the embodiments shown below.

[0049] Note that in this specification and the like, a device manufactured using a metal mask or an FMM (Fine Metal Mask) is sometimes referred to as a device having an MM (Metal Mask) structure. In addition, in this specification and the like, a device not manufactured using a metal mask or an FMM is sometimes referred to as a device having an MML (Metal Mask Less) structure.

[0050] Embodiment 1 Figure 1A It is a schematic diagram of a light-emitting device according to one mode of the present invention. The first electrode 101 of the light-emitting device is provided on the insulator 109, and an organic compound layer 103 (also referred to as an EL layer) is included between the first electrode 101 and the second electrode 102. The organic compound layer 103 includes 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] Preferably, as Figure 1A shown, in addition to the light-emitting layer 113 and the electron injection layer 115, the organic compound layer 103 includes functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115. Note that the organic compound layer 103 may also include functional layers other than the above functional layers such as a hole blocking layer, an electron blocking layer, an exciton blocking layer, and an intermediate layer. Conversely, any of the above layers may not be provided.

[0052] As one of the methods for forming an organic film into a specified shape, a vacuum evaporation method (mask evaporation) using a metal mask is widely employed. However, recently, with the progress of high density and high definition, due to various reasons represented by problems in position alignment accuracy and problems in the arrangement interval with the substrate, the further high definition of mask evaporation is approaching its limit. On the other hand, it is desired to realize an organic semiconductor device having a denser pattern by processing the shape of the organic film using a photolithography method. Moreover, the photolithography method is more easily capable of achieving large area formation compared to mask evaporation, and thus research on organic film processing using the photolithography method is underway.

[0053] On the other hand, since the initial characteristics or reliability of the EL layer in a previously known organic EL device are affected when it is exposed to atmospheric components such as water and oxygen, the EL layer is processed in an atmosphere close to vacuum in common sense steps.

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

[0055] However, in the above process of processing using photolithography, the surface of the EL layer is inevitably exposed to the atmosphere. Therefore, when processing using photolithography, the electron injection property of the electron injection layer using an alkali metal compound, etc. is significantly reduced. As a result, the driving voltage of the organic EL device processed using photolithography including the electron injection layer using an alkali metal compound, etc. rises, and it is difficult to obtain good characteristics.

[0056] Then, in one aspect of the present invention, by using a metal or a metal oxide, a first organic compound including a π-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms as the electron injection layer 115, an organic EL device having good characteristics can be obtained even after a photolithography process accompanied by atmospheric exposure of the organic compound layer.

[0057] By adopting this structure, in the electron injection layer 115, the first organic compound is used as an electron donor (electron supply) with respect to the second organic compound, and the first organic compound, the metal or the metal oxide, and the second organic compound interact to form a donor energy level (singly occupied molecular orbital (SOMO) energy level or highest occupied molecular orbital (HOMO) energy level). When the first organic compound, the metal or the metal oxide, and the second organic compound interact, the donor energy level (SOMO energy level or HOMO energy level) is a high energy level. Therefore, the electron injection barrier from the electron injection layer to the electron transport layer can be reduced, and through this interaction, electrons are smoothly injected from the electron injection layer 115 and transported to the electron transport layer 114. Therefore, a light-emitting device with a low driving voltage can be manufactured.

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

[0059] In addition, the SOMO energy level originates from the orbitals of the unpaired electrons contained in the metal. When the metal or metal oxide, the first organic compound, and the second organic compound interact, the SOMO energy level can also be distributed on the orbitals of the first organic compound and the second organic compound. In other words, it can be said that the electron orbitals of the metal or metal oxide interact with the electron orbitals of the organic compound.

[0060] Note that an organic compound including a plurality of atoms capable of interacting with each other can interact with the metal or metal oxide more stably. Therefore, as the second organic compound used in one embodiment of the present invention, a material that interacts with the metal or metal oxide as a bidentate or polydentate ligand having three or more teeth is preferably used. Since the organic compound that interacts with the metal or metal oxide as a polydentate ligand becomes stable when interacting with the metal or metal oxide, an electron injection layer having resistance to oxygen and water in the atmosphere and water and chemical solutions used in the lithography process can be formed.

[0061] As the atom for such interaction, a heteroatom having a lone pair of electrons in the organic compound can be cited. For example, oxygen (O), nitrogen (N), sulfur (S), and phosphorus (P) can be cited, and nitrogen is preferred. Since nitrogen has a high electronegativity, it easily interacts with the metal or metal oxide. In addition, since nitrogen can form a conjugated bond in the organic compound, an organic compound having high carrier transportability can be realized by using nitrogen in the molecule, particularly in a heteroaromatic ring. Note that the heteroaromatic ring is more preferably an even-membered ring such as a six-membered ring or an eight-membered ring. By adopting this structure, the lone pair of electrons on nitrogen is not involved in conjugation, so it easily interacts with the metal or metal oxide.

[0062] The metal or metal oxide, the first organic compound, and the second organic compound form a donor energy level (SOMO energy level or HOMO energy level) through interaction, which can reduce the electron injection barrier to the electron transport layer, and can smoothly inject and transport electrons from the electron injection layer to the electron transport layer. The heteroaromatic ring included in the second organic compound is preferably a π-deficient heteroaromatic ring. By adopting this structure, the second organic compound can have electron transportability and can smoothly inject and transport electrons from the electron injection layer to the electron transport layer. In addition, the second organic compound includes two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and altogether include three or more nitrogen atoms, whereby the LUMO energy level of the second organic compound can be made lower than the LUMO energy level of the first organic compound. By using a material having a LUMO energy level lower than that of the first organic compound as the second organic compound, stabilization of the intermediate layer can be achieved when the metal or metal oxide, the first organic compound, and the second organic compound interact.

[0063] The first organic compound preferably includes a π-deficient heteroaromatic ring having a non-bonding electron pair. By adopting this structure, it can stably interact with a metal or a metal oxide. The first organic compound is preferably a material that includes two or more π-deficient heteroaromatic rings having non-bonding electron pairs and interacts with a metal or a metal oxide as a multidentate ligand having two or more teeth. Since an organic compound that interacts with a metal or a metal oxide as a multidentate ligand having two or more teeth becomes stable when interacting with the metal or the metal oxide.

[0064] In addition, the first organic compound preferably has an electron-donating substituent. By adopting this structure, the first organic compound can have a high HOMO level and a high LUMO level, so the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound can be increased. Therefore, when a metal or a metal oxide, the first organic compound, and the second organic compound interact, further stabilization of the intermediate layer can be achieved.

[0065] As described above, since stabilization can be achieved when the first organic compound and the second organic compound interact, electrons can be smoothly injected from the electron injection layer and transmitted to an adjacent electron transport layer even after a photolithography process accompanied by atmospheric exposure of the EL layer. Therefore, a light-emitting device can be manufactured by a photolithography process: the rise of the driving voltage is suppressed, the luminous efficiency is good, and it has high reliability.

[0066] In addition, metals having a small work function represented by alkali metals and alkaline earth metals and their compounds have a high reactivity with oxygen or water. Therefore, when they are used in a light-emitting device processed by a lithography technique, it causes a decrease in luminous efficiency, an increase in driving voltage, a decrease in driving life, and the generation of shrinkage (a non-light-emitting region at the end of the light-emitting portion), which sometimes causes a decrease in the characteristics or reliability of the light-emitting device.

[0067] On the other hand, in one aspect of the present invention, even if an alkali metal or an alkaline earth metal or their compounds are used, they interact with the first organic compound including a π-deficient heteroaromatic ring and the second organic compound including two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and altogether include three or more heteroatoms to achieve stabilization. Therefore, an electron injection layer having resistance to oxygen and water in the atmosphere and water and chemical solutions used in the lithography process can be formed.

[0068] When alkali metals, alkaline earth metals, and their compounds are used as the metal in one embodiment of the present invention, the donor energy level (SOMO energy level or HOMO energy level) formed by the interaction between the first organic compound including a π-deficient heteroaromatic ring and the second organic compound including two or more heteroaromatic rings that are bonded or fused to each other and include a total of three or more heteroatoms can be of high energy. Therefore, the electron injection barrier from the electron injection layer to the electron transport layer can be reduced, and electrons can be smoothly injected from the electron injection layer and transported to the electron transport layer, which is preferred.

[0069] In addition, transition metals (metal elements belonging to Groups 3 to 11) and metal elements belonging to Groups 12 to 14 among the typical metals have low reactivity with oxygen and water in the atmosphere and water and chemical solutions used in the lithography process. Therefore, when they are used in a light-emitting device, there is less deterioration caused by water and oxygen that may occur when using a metal with a small work function. On the other hand, this metal is stable and has low electron injection property, so it will cause 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] In the electron injection layer of one embodiment of the present invention, even when using transition metals (metal elements belonging to Groups 3 to 11) and metal elements belonging to Groups 12 to 14 among the typical metals, they interact with the first organic compound including a π-deficient heteroaromatic ring and the second organic compound including two or more heteroaromatic rings that are bonded or fused to each other and include a total of three or more heteroatoms to form a donor energy level (SOMO energy level or HOMO energy level). That is to say, the electron injection barrier from the electron injection layer to the electron transport layer can be reduced, and electrons can be smoothly injected from the electron injection layer and transported to the electron transport layer. In addition, this structure can be resistant to oxygen and water in the atmosphere and water and chemical solutions used in the lithography process. Therefore, one embodiment of the present invention can provide a light-emitting device with good moisture resistance, water resistance, oxygen resistance, chemical resistance, low driving voltage, and good luminous efficiency.

[0071] <Analysis of the Interaction between Metals or Metal Oxides and Organic Compounds by Quantum Chemical Calculations> Here, an analysis using quantum chemical calculations is performed on the case where a metal or metal oxide, a first organic compound having an electron-donating property and having a lone pair of electrons, and a second organic compound having an electron-transporting property interact.

[0072] [Estimation of the Interaction between Metals or Metal Oxides and Organic Compounds] Here, quantum chemical calculations are used to analyze the spin density and electrostatic potential (ESP) when a metal or metal oxide, a first organic compound including a π-deficient heteroaromatic ring, and a second organic compound interact. The second organic compound includes two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and altogether include three or more heteroatoms. Note that in the calculations, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) is used as the first organic compound, 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy) is used as the second organic compound, and lithium (Li) is used as the metal.

[0073] As the quantum chemical calculation program, Gaussian09 is used. The calculation is performed using SGI8600 manufactured by HPE. The most stable structures in the ground state of the first organic compound monomer and the second organic compound monomer, and the most stable structure in the ground state of the composite material of the first organic compound, the second organic compound, and the metal or metal oxide are calculated using density functional theory (DFT). 6-311G(d,p) is used as the basis function, and B3LYP is used as the functional. The total energy of DFT is expressed as the sum of the potential energy, the electrostatic energy between electrons, the kinetic energy of electrons, and the exchange correlation energy including all complex interactions between electrons. In DFT, since a functional of a single-electron potential expressed in terms of electron density (meaning a function of a function) is used to approximate the exchange correlation interaction, the calculation accuracy is high.

[0074] Figure 2 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. The spheres in the attached figure represent the atoms constituting the compound, and the cloud-like objects existing around the atoms represent the spin density distribution when the density value is 0.0004e / a0 in atomic units. 3 (e represents the elementary charge (1e = 1.60218×10 -19 C), and a0 represents the Bohr radius (1a0 = 5.29177×10 -11 m). Note that 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 can be observed.

[0075] When the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) in one embodiment of the present invention is in the doublet ground state, 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 (the nitrogen atoms (N) at the 1st and 10th positions) having non-bonding electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), and the nitrogen atoms having non-bonding electron pairs in the pyridine ring and the benzo[h]quinazoline ring of the second organic compound (6,6’(P-Bqn)2BPy), thereby becoming stable, and thus a composite material is formed. Thus, according to Figure 2 it can be seen that the spin derived from the unpaired electrons contained in the metal (Li) is locally distributed on the second organic compound (6,6’(P-Bqn)2BPy). In addition, the spin density distribution of the metal (Li) is not observed. From this, it can be known 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 the radical anion state.

[0076] Next, Figure 3 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. The spheres in the drawings represent the atoms constituting the compound, and the cloud-like substances existing around the atoms represent the electrostatic potential in the electron density distribution when the density value is 0.0004e / a0 3 in atomic units. 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 refers to the electrostatic potential in the isoelectron density surface represented by colors, where the regions with negative electrostatic potential and positive electrostatic potential are represented by red and blue respectively. The atoms in the region with negative electrostatic potential have negative charges, and the atoms in the positive region have positive charges. Note that since Figure 3 it is a grayscale image, in order to represent the region with negative electrostatic potential and the region with positive electrostatic potential, the dark red part (i.e., the region with negative electrostatic potential) is surrounded by a dashed line, and the dark blue part (i.e., the region with positive electrostatic potential) is surrounded by a dotted line.

[0077] When the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (6,6’(P-Bqn)2BPy), and the metal (Li) in one embodiment of the present invention is in the doublet ground state, 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 (the nitrogen atoms (N) at the 1st and 10th positions) having non-bonding electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), and the nitrogen atoms having non-bonding electron pairs in the pyridine ring and the benzo[h]quinazoline ring of the second organic compound (6,6’(P-Bqn)2BPy) and becomes stable, thereby forming the composite material. As a result, as Figure 3 shown, it can be seen that the positive electrostatic potential is mainly distributed on the metal (Li) and the first organic compound (Pyrrd-Phen), and the negative electrostatic potential is mainly distributed on the second organic compound (6,6’(P-Bqn)2BPy). In addition, it can be seen that the electrostatic potential around the nitrogen atoms having non-bonding electron pairs in the pyridine ring and the 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. Furthermore, the Mulliken partial charge of this Li atom is +0.691e in the atomic unit system.

[0078] [Estimation of SOMO energy level or stabilization energy] Next, quantum chemical calculations are used to estimate the stabilization energy when a metal or metal oxide, a first organic compound including a π-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings, where the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms, interact with each other, and the SOMO energy level formed at this time.

[0079] As a quantum chemistry calculation program, Gaussian09 is used. The calculations are performed using an SGI8600 manufactured by HPE. First, the most stable structures of the first organic compound, the second organic compound, and the metal or metal oxide in their respective ground states, 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 most stable structures of the composite materials of the first organic compound, the second organic compound, and the metal or metal oxide in their ground states are calculated using density functional theory (DFT). 6-311G(d,p) and LanL2DZ are used as the basis functions, and B3LYP is used as the exchange-correlation functional. Then, the stabilization energy is calculated based on 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 energies of the organic compound monomer and the metal or metal oxide monomer. In other words, (stabilization energy) = (total energy of the composite material of the organic compound and the metal or metal oxide) - (total energy of the organic compound monomer) - (total energy of the metal or metal oxide monomer) holds.

[0080] The calculation results of the following composite materials are shown in Table 1 below: Lithium (Li) is used as the metal or metal oxide, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) is 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) is used as the second organic compound. Additionally, for comparison, the calculation results of the following composite materials are also shown: A composite material in which lithium (Li) is used as the metal or metal oxide, Pyrrd-Phen is used as the first organic compound, and 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen) is used as the second organic compound instead of 6,6'(P-Bqn)2BPy; a composite material using lithium (Li) and Pyrrd-Phen; a composite material using lithium (Li) and 6,6'(P-Bqn)2BPy; and a composite material using lithium (Li) and NBphen. Note that 6,6'(P-Bqn)2BPy is a second organic compound that includes two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms. On the other hand, NBphen is an organic compound that includes two or more heteroaromatic rings, and although the two or more heteroaromatics are bonded or fused to each other, the total number of heteroatoms is less than 3.

[0081] [Table 1]

[0082] [Table 2] LUMO(eV) HOMO(eV) Pyrrd-Phen -1.35 -5.65 6,6'(P-Bqn)2BPy -2.07 -5.99 tPy -1.65 -6.37 2Py3Tzn -2.20 -6.89 NBPhen -2.04 -5.74

[0083] As can be seen from Table 1 above, the absolute value of the negative of 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 embodiment of the present invention is relatively large. This means that: compared with the case where the organic compound does not interact with the metal or metal oxide, the energy is more stable when the organic compound interacts with the metal or metal oxide. The SOMO energy level formed at this time is higher than the HOMO energy levels of the first organic compound (Pyrrd-Phen) and the second organic compound (6,6’(P-Bqn)2BPy) shown in Table 2, the difference from their respective LUMO energy levels is small and the electron injection property is excellent, so it is preferred. Note that the energy levels of SOMO, HOMO, and LUMO in Table 1 and Table 2 are values obtained by calculation, and sometimes their absolute values are different from the measured values.

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

[0085] In addition, the stabilization energy of the composite material of lithium (Li) and the first organic compound (Pyrrd-Phen) is negative, and the composite material obtained by adding the second organic compound to this composite material is more stable.

[0086] The SOMO energy level of the composite material of lithium (Li) and the second organic compound (6,6’(P-Bqn)2BPy) is slightly lower, and the electron injection property is higher when the first organic compound is included. In addition, the stabilization energy of the composite material of lithium (Li) and NBphen is negative, more stable and the SOMO energy level is lower when the first organic compound is included, so the electron injection property is higher when the first organic compound is included. That is to say, the composite material using a metal or metal oxide, the first organic compound including a π-deficient heteroaromatic ring, and the second organic compound in one embodiment of the present invention is stable and has excellent electron injection property, and is suitable for use in an electron injection layer. The second organic compound includes two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms.

[0087] Next, the following table shows the calculation results of the following composite materials: using a metal belonging to Group 11 or Group 13 or a metal oxide, specifically using silver (Ag) or indium (In); using Pyrrd-Phen as the first organic compound; using 4',4''-(1,4-phenylene)bis(2,2':6',2''-terpyridine) (abbreviation: tPy2P) or 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tzn) as the second organic compound. Additionally, for comparison, the calculation results of the following composite materials are also shown: using silver (Ag) or indium (In) as the metal or metal oxide, using Pyrrd-Phen as the first organic compound, and using NBphen instead of the second organic compound. Note that tPy2P and 2Py3Tzn are the second organic compounds, which include two or more heteroaromatic rings, and the two or more heteroaromatic rings are bonded or fused to each other and altogether include three or more heteroatoms. On the other hand, NBphen is an organic compound that includes two or more heteroaromatic rings, and although the two or more heteroaromatics are bonded or fused to each other, the total number of heteroatoms is less than 3.

[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 embodiment of the present invention has a high stabilization energy and a stable structure, so it is preferable. In addition, the SOMO energy level formed at this time is high and the electron injection property is excellent, so it is preferable.

[0091] Note that considering the manufacturing process of the light-emitting device, generally, in many cases, the EL layer of the light-emitting device, especially the electron injection layer, is deposited by vacuum evaporation. As the material used at this time, a material that can be easily vacuum-evaporated, that is, a material with a low melting point, is preferably used. Since the metals belonging to Group 11 elements and Group 13 elements have a low melting point, they can be applied to vacuum evaporation. In addition, the metals belonging to Group 11 elements and Group 13 elements are stable to oxygen and water in the atmosphere, so they are preferable. In addition, by using the vacuum evaporation method, metal atoms and organic compounds can be easily mixed, so it is preferable.

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

[0093] It can be seen therefrom that when a first organic compound including a π-deficient heteroaromatic ring, a metal or a metal oxide, and a second organic compound including two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or fused to each other and include a total of three or more heteroatoms, interact with each other, the first organic compound and the metal or the metal oxide act as an electron donor to the second organic compound. In one embodiment of the present invention, by using the combination of materials for the electron injection layer, an electron injection layer having excellent electron injection characteristics and being resistant to oxygen and water in the atmosphere and water and chemical solutions used in the processes in lithography can be formed. Therefore, a light-emitting device with a reduced driving voltage and high luminous efficiency can be obtained.

[0094] <<Electron injection layer>> As Figure 1A shown, the electron injection layer 115 is disposed between the second electrode 102 as a cathode and the light-emitting layer 113, and contains a metal or a metal oxide, a first organic compound including a π-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings, wherein the two or more heteroaromatic rings are bonded or fused to each other and include 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, an earth metal (Group 13 element) such as Al, In, a Group 14 element such as Sn, or a compound thereof can be used.

[0097] When an alkali metal or an alkaline earth metal or a compound thereof is used as the metal, the donor energy level formed by the interaction between the first organic compound and the second organic compound can be a high energy level. Thereby, electrons can be smoothly injected from the electron injection layer and transmitted to the electron transport layer, and a light-emitting device with a low driving voltage and high-efficiency light emission can be provided, so it is preferred.

[0098] As the transition metal, a Group 3 element including Y and lanthanide elements such as Eu and 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 has low reactivity with components such as water and oxygen in the atmosphere, so it is preferred.

[0099] Among the above-mentioned metals, metals belonging to odd-numbered groups (Group 1, Group 3, Group 5, Group 7, Group 9, Group 11, or Group 13) are more preferably used. Among these transition metals belonging to odd-numbered groups, metals having one electron (unpaired electron) in the outermost orbit are likely to form SOMO with the first organic compound, and thus are particularly preferred.

[0100] In addition, metals with low melting points that can be deposited by vacuum evaporation are likely to form a mixed layer with the organic compound, and thus are preferred. Specifically, for example, metals belonging to Group 11 elements and Group 13 elements have low melting points, and thus can be applied to vacuum evaporation. In addition, metals belonging to Group 11 elements and Group 13 elements are stable against oxygen and water in the atmosphere, and thus are preferred.

[0101] <The first organic compound> As the first organic compound, an organic compound including a π-deficient heteroaromatic ring can be used. In addition, in order for the first organic compound to interact with the metal or metal oxide and act as an electron donor (electron giver) to the second organic compound, the π-deficient heteroaromatic ring preferably has a non-bonding electron pair, and the non-bonding electron pair preferably has electron-donating properties. That is to say, the first organic compound preferably includes a basic π-deficient heteroaromatic ring. In addition, nitrogen has a high electronegativity, and thus is likely to interact with the metal or metal oxide. In addition, since nitrogen can form a conjugated bond in the organic compound, by using nitrogen in the molecule, especially in the heteroaromatic ring, an organic compound with high carrier transportability can be realized. Therefore, the first organic compound preferably includes a heteroaromatic ring containing nitrogen. Note that the heteroaromatic ring is more preferably an even-membered ring such as a six-membered ring or an eight-membered ring. By adopting this structure, the non-bonding electron pair on nitrogen is not involved in conjugation, and thus it is easy to generate an interaction with the metal or metal oxide. In addition, 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 transportability. Specifically, for example, the first organic compound preferably includes a pyridine ring.

[0102] In addition, the first organic compound is preferably a material including two or more π-deficient heteroaromatic rings having non-bonding electron pairs, and the two or more π-deficient heteroaromatic rings are bonded or fused to each other. Thus, when the metal or metal oxide as a bidentate ligand or a multidentate ligand with two or more teeth interacts with the first organic compound and the second organic compound, it becomes stable, and thus an electron injection layer that is not easily deteriorated even after a photolithography process accompanied by atmospheric exposure can be formed. Specifically, for example, the first organic compound preferably includes a heteroaromatic ring containing two or more pyridine rings. Among them, the nitrogen atom of the organic compound having a bipyridine skeleton is likely to coordinate with the metal, and thus is likely to interact with the metal or metal oxide, and thus is preferred.

[0103] Moreover, the phenanthroline ring is rigid and highly stable, so it is preferred. In particular, in the phenanthroline ring, the two nitrogen atoms in the organic compound having a 1,10-phenanthroline ring can coordinate to a metal, and thus it is easy to interact with a metal or a metal oxide, so it is preferred.

[0104] In addition, the first organic compound may also have a structure in which a plurality of phenanthroline rings are connected by a single bond or through 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 a divalent group having a structure in which one hydrogen atom is further 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 include a divalent group having a structure in which one hydrogen atom is further removed from the specific examples of the aryl group described later. The arylene group may also have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0107] In addition, the first organic compound preferably has an electron-donating substituent. Thereby, the first organic compound can have a high HOMO level and a high LUMO level, so that the difference between the LUMO level of the first organic compound and the LUMO level of the second organic compound can be increased, and further stabilization of the intermediate layer can be achieved when the metal or metal oxide, the first organic compound, and the second organic compound interact with each other, and thus an electron injection layer that is not easily deteriorated even after a photolithography process accompanied by atmospheric exposure can be formed.

[0108] In addition, as the first organic compound, an organic compound including a phenanthroline ring having an electron-donating group is more preferably used. In particular, by introducing an electron-donating group onto the 1,10-phenanthroline ring, the electron density of the phenanthroline ring can be increased and the efficiency of interaction with a metal or a metal oxide can be improved. And preferably, at least one of the 4-position and the 7-position of the 1,10-phenanthroline ring has an electron-donating group. By introducing an electron-donating group at the 4-position and the 7-position, the electron density of the nitrogen atoms at the 1-position and the 10-position in the para-position thereof can be increased. In addition, steric hindrance around the nitrogen atoms at the 1-position and the 10-position can be avoided, and the electron density around the same can be increased. Therefore, it can easily interact with a metal or a metal oxide, so it is preferred.

[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, etc. However, the electron-donating group preferably introduced into a π-deficient heteroaromatic ring such as a phenanthroline ring is not limited thereto. As long as a group that can increase the electron density of a π-deficient heteroaromatic ring is introduced into a π-deficient heteroaromatic ring such as a phenanthroline ring, it can be used as an electron-donating group. In addition, the electron-donating group may also be introduced into a π-deficient heteroaromatic ring such as a phenanthroline ring through an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0110] The alkyl group represents a monovalent group obtained by removing one hydrogen atom from an alkane (C n H 2n+2 ). Specific examples of the alkyl group 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, etc.

[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 a methoxy group, an ethoxy group, a n-propoxy group, an isopropoxy group, a n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, a n-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a tert-pentyloxy group, a neopentyloxy group, a n-hexyloxy group, an isohexyloxy group, a sec-hexyloxy group, a tert-hexyloxy group, a neohexyloxy group, etc.

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

[0113] The 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, etc.

[0114] The 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, etc. The arylamino group may also have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, etc.

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

[0116] A heterocyclic amino group represents a monovalent group obtained by removing one hydrogen atom from one of the ring-forming nitrogen atoms of a heterocyclic amine. Note that here, a heterocyclic amine refers to a monocyclic or polycyclic heterocyclic compound, and represents a compound in which at least one of the ring-forming atoms 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 also have a substituent, and specific examples of such a substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0117] [Chemical formula 3]

[0118] Note that in the case where the heterocyclic amino group has aromaticity and the non-bonding electron pair of the nitrogen atom contributes to the aromaticity, the electron-donating property to the phenanthroline ring may sometimes be reduced compared to the case where the non-bonding electron pair of the nitrogen atom does not contribute to the aromaticity. Therefore, among the above heterocyclic amino groups, it is more preferable to use a heterocyclic amino group in which the non-bonding electron pair of the nitrogen atom does not contribute to the aromaticity. Specifically, groups represented by the structural formula (R-1), the structural formula (R-2), the structural formula (R-3), the structural formula (R-4), the structural formula (R-5), the structural formula (R-8), the structural formula (R-9), the structural formula (R-10), the structural formula (R-12), the structural formula (R-14), the structural formula (R-15), the structural formula (R-16), the structural formula (R-17), or (R-21) are more preferable as electron-donating groups. Among them, groups represented by the structural formula (R-3), the structural formula (R-4), the structural formula (R-8), or the structural formula (R-21) have a high electron-donating property and can further increase the electron density of the phenanthroline ring, so they are preferable.

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

[0120] [Chemical formula 4]

[0121] Note that the organic compound including a π - electron - deficient heteroaromatic ring that can be used as the first organic compound may also have both the above - mentioned electron - donating group and substituents other than that. As specific examples of the substituents that can be introduced into the π - electron - deficient heteroaromatic ring other than the above - mentioned electron - donating group, aryl groups can also be cited. As specific examples of aryl groups, phenyl, o - tolyl, m - tolyl, p - tolyl, mesityl, o - biphenylyl, m - biphenylyl, p - biphenylyl, 1 - naphthyl, 2 - naphthyl, 2 - fluorenyl, etc. can be cited. The aryl group may also have substituents. As specific examples of such substituents, alkyl groups, alkoxy groups, phenyl groups, etc. can be cited.

[0122] Specific examples of the organic compound including a π - electron - deficient heteroaromatic ring that can be used as the first organic compound are represented by structural formulas (100) to (110). Note that the organic compounds that can be used as the first organic compound are not limited to these.

[0123] [Chemical formula 5]

[0124] In addition, when the minimum value of the electrostatic potential (ESP: Electrostatic Potential) of the first organic compound is small (the absolute value of the negative value is large), the stability of the interaction with a metal or metal oxide is improved, so it is preferred. In an organic compound including a π - electron - deficient heteroaromatic ring, the electrostatic potential tends to be negative around the nitrogen atom of the π - electron - deficient heteroaromatic ring. However, by introducing an electron - donating group onto the π - electron - deficient heteroaromatic ring, the electrostatic potential around the nitrogen atom of the π - electron - deficient heteroaromatic ring can be further reduced (the absolute value of the negative value is increased). The electrostatic potential refers to the interaction energy between a positive point charge with a unit electric charge and the electron distribution of the molecule. In addition, the value of the electrostatic potential also varies according to the threshold of the electron density distribution. In order to improve 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 less than the minimum value of the electrostatic potential of a phenanthroline ring without substituents (larger in the negative direction). Specifically, when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 , the minimum value of the electrostatic potential is preferably - 0.085E h (E h represents Hartree energy (1E h = 27.211eV)) or less, more preferably - 0.090E h or less. In addition, when the threshold of the electron density distribution is 0.003e / a0 3 , the minimum value of the electrostatic potential is preferably - 0.12E h or less, more preferably - 0.13E h or less.

[0125] <<Estimating the Properties of the First Organic Compound Using Quantum Chemical Calculations>> Estimate the minimum value of the electrostatic potential (ESP) of the organic compound that can be used as the first organic compound using quantum chemical calculations.

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

[0127] The following table shows the analysis results of the electrostatic potential in the ground state of the first organic compound. The electrostatic potential refers to the interaction energy between a positive point charge with a unit electric charge and the electron distribution of the molecule. In addition, the value of the electrostatic potential also varies according to the threshold of the electron density distribution. The following table shows the electrostatic potential of the electron density distribution when the threshold of the electron density distribution is set to 0.0004e / a0 3 or 0.003e / a0 3 in atomic units.

[0128] [Table 5] Minimum value of ESP (density threshold = 0.0004) Minimum value of ESP (density threshold = 0.003) Pyrrd-Phen(100) -0.091 -0.12 DMeAPhen(101) -0.089 -0.12 p-MeO-Phen(102) -0.089 -0.12 4,7hpp2Phen(103) -0.096 -0.13 CzPhen(104) -0.072 -0.10 mhppPhen2P(105) -0.057 -0.096 9Ph2hppPhen(106) -0.057 -0.096 2,9hpp2Phen(107) -0.061 -0.097 BPhen -0.083 -0.11 mPPhen2P -0.057 -0.094 NBPhen -0.053 -0.093 Phen -0.081 -0.11

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

[0130] [Chemical Formula 6]

[0131] As can be seen from the above table, for the organic compounds represented by structural formulas (100) to (103), when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 the minimum value of ESP is -0.085E h Therefore, it is most suitable as the first organic compound. On the other hand, it can be seen that the minimum value of ESP of the organic compounds represented by structural formulas (104) to (107) is greater than -0.085E h .

[0132] 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.

[0133] The organic compound represented by the structural formula (104) is an organic compound having electron-donating groups at the 4-position and 7-position of the 1,10-phenanthroline ring, and an N-carbazolyl group is used as the electron-donating group. In the N-carbazolyl group, the non-bonding electron pair of the nitrogen atom contributes to aromaticity, so compared with a group in which the non-bonding electrons of the nitrogen atom do not contribute to aromaticity, the electron-donating property to the phenanthroline ring is reduced. Therefore, the minimum value of ESP is not easily decreased, and the above results are obtained.

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

[0135] Note that the LUMO energy level of the second organic compound is more preferably lower than the LUMO energy level of the first organic compound. Thereby, electrons can be easily supplied from the donor energy level formed by the first organic compound and the metal or metal oxide to the second organic compound. In addition, the second organic compound preferably has electron-transporting properties, and for this purpose, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound.

[0136] For example, the LUMO energy level of the first organic compound is preferably -3.0 eV or more and -2.0 eV or less, more preferably -2.7 eV or more and -2.0 eV or less. In addition, the LUMO energy level of the second organic compound is preferably -3.0 eV or more and -2.0 eV or less, more preferably -3.0 eV or more and -2.5 eV or less. Thereby, electrons can be easily supplied from the donor energy level formed by the first organic compound and the metal or metal oxide to the second organic compound. In addition, the electron transport in the second organic compound becomes easy thereby.

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

[0138] In addition, when the first organic compound has high basicity, the hole transport property of the electron injection layer can be significantly reduced by interacting with holes to prevent holes from being transported from the electron injection layer to the electron transport layer, and thus a highly efficient light-emitting device can be obtained, so it is preferable. Specifically, the acidity coefficient pK a is preferably 8 or more, more preferably 10 or more, and further preferably 12 or more.

[0139] In addition, when the acid dissociation constant pK of an organic compound is a unknown, by investigating the acid dissociation constant pK of each skeleton of the organic compound a , the largest acid dissociation constant pK among them a can be regarded as the acid dissociation constant pK of the organic compound a .

[0140] In addition, the acid dissociation constant can also be calculated. For example, the acid dissociation constant pK can be calculated using the following calculation method a .

[0141] The initial structure of the molecular structure of each molecule as the calculation model adopts the most stable structure (singlet ground state) obtained by first-principles calculation.

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

[0143] In the pK a calculation, one or more atoms in each molecule are designated as basic positions, Macro Model is used to explore the structure in which the protonated molecule is stable in water, and the conformational isomer with the lowest energy obtained by conformational exploration using the OPLS2005 force field is used. The pK a calculation module of Jaguar is used to optimize its structure with B3LYP / 6-31G*, and then a single-point calculation is performed with cc-pVTZ(+), and the pK a value is calculated using the empirical correction for the functional group. In the molecule in which one or more atoms are designated as basic positions, the largest value in the obtained results is used as the pK a value. The obtained pK a value is shown.

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

[0145] <Second organic compound> The electron injection layer includes a second organic compound in addition to the metal or metal oxide and the first organic compound. The second organic compound includes two or more heteroaromatic rings bonded or fused to each other, and the two or more heteroaromatic rings in total include three or more heteroatoms. In addition, the second organic compound has a function of interacting with the metal or metal oxide by two or more of the three or more heteroatoms as a multidentate ligand.

[0146] By including the second organic compound, an improvement in heat resistance and an improvement in electron transportability can be achieved. In one aspect of the present invention, when the π-deficient heteroaromatic ring included in the first organic compound is a first π-deficient heteroaromatic ring and the π-deficient heteroaromatic ring included in the second organic compound is a second π-deficient heteroaromatic ring, the first π-deficient heteroaromatic ring and the second π-deficient heteroaromatic ring preferably include different rings.

[0147] In addition, as the second π-deficient heteroaromatic ring, heteroaromatic rings having an oxazole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), heteroaromatic rings having a pyridine skeleton, heteroaromatic rings having a diazine skeleton, and heteroaromatic rings having a triazine skeleton are preferably used. Among them, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring is electrochemically stable and has high electron transportability, so it is preferred.

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

[0149] [Chemical formula 7]

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

[0151] The organic compound represented by the general formula (G1-1) has conjugated double bonds formed by N on the heteroaromatic ring arranged in the order of N-C-C-N, and has a function of interacting with a metal or a metal oxide as a ligand with three or more teeth. Since the organic compound having such a structure easily interacts with a metal or a metal oxide, it can be applied to an electron injection layer.

[0152] In the above general formula (G1-1), as the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by A 1 、A 2 and A 3 , for example, a heteroaromatic ring having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, anthyridine ring, azafluoranthene ring), a heteroaromatic ring 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), a heteroaromatic ring having a triazine skeleton, a heteroaromatic ring having an oxazole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. Note that 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 this. A 1 、A 2 and A 3 may also form a fused ring with each other. For example, A 1 and A 2 may also bond to each other to form a phenanthroline ring.

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

[0154] [Chemical formula 8]

[0155] In the general formula (G2-1), X 1 to X 6 each independently represents carbon (C) or nitrogen (N), and carbon (C) is bonded to hydrogen, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms which is substituted or unsubstituted, an aryl group having 6 or more and 30 or less carbon atoms which is substituted or unsubstituted, or a heteroaryl group having 1 to 30 carbon atoms which is substituted or unsubstituted, and R 1 to R 4Each independently represents 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 to 30 carbon atoms. Alternatively, in the general formula (G2-1), X 1 to X 6 may also form a fused ring directly with each other or through a carbon bond.

[0156] As in the case of the organic compound represented by the general formula (G2-1), an organic compound having a function of interacting with a metal or a metal oxide as a ligand of three or more teeth preferably includes at least one of a heteroaryl ring having a pyridine skeleton, a heteroaryl ring having a diazine skeleton, and a heteroaryl ring having a triazine skeleton. Since the electrochemical stability of these rings is excellent, a light-emitting device with good reliability can be provided. In addition, since the electron transport property is excellent, a light-emitting device with a reduced driving voltage can be provided.

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

[0158] [Chemical formula 9]

[0159] In the general formula (G3-1), X 1 to X 4 each independently represents carbon (C) or nitrogen (N), and 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 to 30 carbon atoms, and R 1 to R 6 each independently represents 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 to 30 carbon atoms.

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

[0161] [Chemical formula 10]

[0162] In the general formula (G4-1), X 1 to X 5Each independently represents carbon (C) or nitrogen (N), and 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 to 30 carbon atoms, R 1 to R 5 Each independently represents 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 to 30 carbon atoms.

[0163] An organic compound having a pyridine skeleton has a high LUMO energy level and is thus preferred. Therefore, when X 1 and X 2 represented by the general formulas (G2-1) to (G4-1) represent carbon, the organic compound has a pyridine skeleton, and thus a composite material having a high SOMO energy level can be formed when interacting with a metal or a metal oxide. In other words, an organic compound having a pyridine ring and having a function of interacting as a ligand of three or more teeth 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 electrochemically stable and has high electron transportability, and is thus preferred. Therefore, when at least one of X 1 and X 2 represented by the general formulas (G2-1) to (G4-1) represents nitrogen, the organic compound has a diazine skeleton or a triazine skeleton, and thus a stable composite material having high electron transportability can be formed when interacting with a metal or a metal oxide. In other words, an organic compound having a diazine ring or a triazine ring and having a function of interacting as a ligand of three or more teeth can form an electron injection layer having high reliability by interacting with a metal or a metal oxide.

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

[0166] [Chemical formula 11]

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

[0168] The organic compound represented by the general formula (G1-2) has conjugated double bonds formed by N on the heteroaromatic ring arranged in the order of N-C-C-N, and has a function of interacting with a metal or a metal oxide as a ligand having two or more teeth. The organic compound having such a structure easily interacts with a metal or a metal oxide, so it can be applied to an electron injection layer.

[0169] In the above general formula (G1-2), as the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by A 1 For example, 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 oxazole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. can be cited. As the substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms represented by A 2 For example, heteroaromatic rings having a pyridine skeleton (pyridine ring, quinoline ring, isoquinoline ring, naphthyridine ring, bipyridine ring, phenanthridine ring, phenanthroline ring, acridine 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 oxazole skeleton (imidazole ring, benzimidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), etc. can be cited. Note that the substituted or unsubstituted heteroaromatic rings having 1 to 30 carbon atoms represented by A 1 and A 2 are not limited to this. A 1 and A 2 can also form a condensed ring with each other. For example, A 1 and A 2 can also bond to each other to form a pyrazinoquinoxaline ring.

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

[0171] [Chemical formula 12]

[0172] In the general formula (G2-2), X 1 to X 4At least one of them represents nitrogen (N), and the rest 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 to 30 carbon atoms, R 1 to R 4 each independently represents 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 to 30 carbon atoms. Alternatively, in the general formula (G2-2), X 1 to X 4 may also form a condensed ring directly with each other or through a carbon bond.

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

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

[0175] [Chemical formula 13]

[0176] In the general formula (G3-2), one of X 1 and X 2 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 or more and 30 or less carbon atoms, or a substituted or unsubstituted heteroaryl group having 1 to 30 carbon atoms, R 1 to R 6 each independently represents 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 to 30 carbon atoms.

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

[0178] [Chemical Formula 14]

[0179] In the general formula (G4-2), at least one of X 1 to X 3 represents nitrogen (N), and the rest 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 to 30 carbon atoms. R 1 to R 5 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 to 30 carbon atoms.

[0180] The organic compound having a pyridine skeleton has a high LUMO energy level, so it is preferred. Therefore, when X 1 and X 2 represented by the general formulas (G2-2) and (G4-2) and X 1 represented by the general formula (G3-2) represent carbon, the organic compound has a pyridine skeleton, and thus can form a composite material having a high SOMO energy level when interacting with a metal or a metal oxide. In other words, an organic compound having a pyridine ring and having a function of interacting as a bidentate or higher ligand can form an electron injection layer having high electron injectability by interacting with a metal or a metal oxide.

[0181] In addition, the organic compound having a diazine skeleton or a triazine skeleton is electrochemically stable and has high electron transportability, so it is preferred. Therefore, when at least one of X 1 and X 2 represented by the general formulas (G2-2) and (G4-2) and X 1 represented by the general formula (G3-2) represents nitrogen, the organic compound has a diazine skeleton or a triazine skeleton, and thus can form a stable and highly electron-transporting composite material when interacting with a metal or a metal oxide. In other words, an organic compound having a diazine ring or a triazine ring and having a function of interacting as a bidentate or higher ligand can form an electron injection layer having high reliability by interacting with a metal or a metal oxide.

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

[0183] [Chemical Formula 15]

[0184] [Chemical Formula 16]

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

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

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

[0188] Specific examples of aryl groups having 6 to 30 carbon atoms include phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenylyl, m-biphenylyl, p-biphenylyl, 1-naphthyl, 2-naphthyl, fluorenyl, 9,9-dimethylfluorenyl, spirobifluorenyl, phenanthryl, anthryl, fluoranthenyl, and the like. When the aryl group having 6 to 30 carbon atoms has a substituent, examples of the substituent include alkyl groups having 1 to 10 carbon atoms, cycloalkyl groups having 3 to 10 carbon atoms, phenyl, and the like.

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

[0190] A heteroaryl group having 1 to 30 carbon atoms refers to a monovalent group obtained by removing one hydrogen atom from one of the ring-forming carbon atoms 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 1,3,5-triazin-2-yl, 1,2,4-triazin-3-yl, pyrimidin-4-yl, pyrazin-2-yl, 2-pyridyl, 3-pyridyl, 4-pyridyl, carbazolyl, dibenzofuranyl, dibenzothiophenyl, benzonaphthofuranyl, benzonaphthothiophenyl, indolocarbazolyl, benzofurocarbazolyl, benzothiophenocarbazolyl, indolocarbazolyl, dibenzocarbazolyl, etc. 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, etc.

[0191] Specific examples of the organic compound used as 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 17]

[0193] [Chemical formula 18]

[0194] [Chemical formula 19]

[0195] Note that the LUMO energy level of the second organic compound is more preferably lower than the LUMO energy level of the first organic compound. Thus, electrons can be easily supplied from the donor energy level formed by the first organic compound and the metal or metal oxide to the second organic compound. In addition, the second organic compound preferably has electron-transporting properties, and for this purpose, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound.

[0196] The LUMO energy 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 further preferably -3.0 eV or more and -2.5 eV or less. In addition, the LUMO energy level of the first organic compound is preferably -3.0 eV or more and -2.0 eV or less, more preferably -2.7 eV or more and -2.0 eV or less.

[0197] Thus, electrons can be easily supplied from the donor energy level formed by the first organic compound and the metal or metal oxide to the second organic compound. In addition, this can facilitate the transport of electrons in the second organic compound.

[0198] Further, in one embodiment of the present invention, the LUMO energy level of the second organic compound is preferably lower than that of the first organic compound, and is preferably a value of 0.6 eV or more lower than the LUMO energy level of the first organic compound (preferably 0.50 eV) and 0.20 eV or less lower than the LUMO energy level of the first organic compound. More preferably, it is a value of 0.50 eV or more lower than the LUMO energy level of the first organic compound and 0.25 eV or less lower than the LUMO energy level of the first organic compound. More preferably, it is a value of 0.50 eV or more lower than the LUMO energy level of the first organic compound and 0.30 eV or less lower than the LUMO energy level of the first organic compound. More preferably, it is a value of 0.50 eV or more lower than the LUMO energy level of the first organic compound and 0.35 eV or less lower than the LUMO energy level of the first organic compound. Further preferably, it is a value of 0.50 eV or more lower than the LUMO energy level of the first organic compound and 0.40 eV or less lower than the LUMO energy level of the first organic compound.

[0199] That is, when the LUMO energy level of the first organic compound is denoted as "LUMO1 (eV)" and the LUMO energy level of the second organic compound is denoted as "LUMO2 (eV)", LUMO2 preferably satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.20

[0200] Further, more preferably, LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.25

[0201] Further, more preferably, LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.30

[0202] Further, more preferably, LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.35

[0203] Further, more preferably, LUMO2 satisfies the following formula. LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.40

[0204] When LUMO2 is within the above range, as a light-emitting device according to one embodiment of the present invention, a light-emitting device with a low driving voltage and good characteristics can be realized regardless of whether it undergoes a photolithography process accompanied by atmospheric exposure of the EL layer. In addition, a light-emitting device with high reliability can be realized.

[0205] As the second organic compound, an organic compound having electron transporting properties can be used. As the organic compound having electron transporting properties, it is preferable to use a substance having an electron mobility of 1×10 - 7 cm 2 / Vs or more when the square root of the electric field strength [V / cm] is 600, and it is more preferable to use a substance having an electron mobility of 1×10 -6 cm 2 / Vs or more. In addition, as long as the substance has higher electron transporting properties than hole transporting properties, substances other than the above can also be used.

[0206] In addition, the number of carbon atoms of the second organic compound is preferably 25 or more and 100 or less. By adopting such a number of carbon atoms, an organic compound with good sublimability can be realized, thereby suppressing the thermal decomposition of the organic compound during vacuum evaporation, and thus good utilization efficiency of the material 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 have high heat resistance and is not easily crystallized. Therefore, a layer that is not easily crystallized even when a part of the organic compound layer is processed by lithography technology can be realized.

[0208] In addition, as the second organic compound, an organic compound having an acidity coefficient pK a less than 4 can be used. Thereby, the water solubility of the second organic compound can be reduced, and thus the resistance to water and chemical solutions used in the lithography process can be improved.

[0209] Compared with the water solubility of an organic compound having an acidity coefficient pK a of 4 or more, the water solubility of an organic compound having an acidity coefficient pK a less than 4 is low. In addition, compared with the case where an organic compound having an acidity coefficient pK a of 4 or more is used as the second organic compound, by using an organic compound having an acidity coefficient pK a less than 4 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 defects such as peeling of the electron injection layer from other layers can be suppressed. Thereby, the occurrence of defects that cause defects in the light-emitting device can be suppressed.

[0210] In addition, when the acidity coefficient pK a of the organic compound is unknown, by investigating the acidity coefficient pK a of each skeleton of the organic compound, the largest acidity coefficient pK a can be regarded as the acidity coefficient pK a of the organic compound.

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

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

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

[0214] In the first layer, the molar ratio of the metal or metal oxide is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and further preferably 0.5 or more and 2 or less, based on the first organic compound (or the sum of the first organic compound and the second organic compound). Alternatively, the volume ratio is preferably 0.01 or more and 0.3 or less, more preferably 0.02 or more and 0.2 or less, and further preferably 0.05 or more and 0.1 or less. By including the first layer containing a metal or metal oxide and a first organic compound (or a first organic compound and a second organic compound) in such a ratio, an electron injection layer with good electron injection properties can be provided. In addition, the second organic compound may not be used, but when the second organic compound is used, the volume 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 further preferably 0.5 or more and 2 or less, based on the second organic compound. By mixing the first organic compound and the second organic compound in such a ratio, an electron injection layer with good electron transport properties can be provided. In addition, by using an organic compound with good thermal properties and a high Tg as the second organic compound, an organic EL device with high reliability can be provided.

[0215] In addition, the thickness of the first layer is preferably 2 nm or more and 20 nm or less, 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 a first organic compound, the layer of the metal or metal oxide is preferably 0.1 nm or more and 5 nm or less, more preferably 0.2 nm or more and 2 nm or less. In addition, in the case where the first layer has a laminated structure of a layer of a metal or metal oxide and a layer containing a first organic compound, the thickness of the layer containing the first organic compound is preferably 2 nm or more and 20 nm or less, more preferably 5 nm or more and 10 nm or less.

[0216] By using the above-mentioned second organic compound, a composite material formed by mixing a mixed metal or metal oxide, a first organic compound, and a second organic compound can function well, thereby providing a light-emitting device with high luminous efficiency.

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

[0218] Figure 1A It is a schematic diagram of a light-emitting device according to one aspect of the present invention. In the light-emitting device, a first electrode 101 is provided on an insulator 109, and an organic compound layer 103 is included between the first electrode 101 and the second electrode 102. The organic compound layer 103 includes 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.

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

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

[0221] The specific structure of the electron injection layer 115 has been described in detail in Embodiment 1, so repeated description is omitted here.

[0222] Note that, although in this embodiment, the first electrode 101 is an electrode including an anode, the second electrode 102 is an electrode including a cathode, and an example in which the first electrode 101 is formed on one side of the insulator 109 is shown, a structure in which the second electrode 102 is formed on one side of the insulator 109, that is, a so-called reverse stacking structure, may also be adopted. At this time, the light-emitting device has a stacked structure in which 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 are sequentially stacked from one side of the insulator 109. When the light-emitting device having this reverse stacking structure is used, the relatively stable hole injection layer 111 becomes the surface, whereby a light-emitting device with higher reliability can be realized.

[0223] In addition, the first electrode 101 and the second electrode 102 are 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 is used as an anode or a cathode. When the electrode has a stacked structure, there is no work function limitation on the layers other than the layer in contact with the organic compound layer 103, and materials can be selected according to required characteristics such as resistance value, processing convenience, reflectivity, light transmittance, and stability.

[0224] The anode is preferably formed of a metal, alloy, conductive compound, or a mixture thereof having 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 oxide containing tungsten oxide and zinc oxide (IWZO), etc. can be cited. Although these conductive metal oxide films are usually formed by sputtering, sol-gel methods or the like can also be applied for formation. As an example of the formation method, a method of forming indium zinc oxide by sputtering using a target in which 1 wt% to 20 wt% of zinc oxide is added to indium oxide can be cited. In addition, indium oxide containing tungsten oxide and zinc oxide (IWZO) can be formed by sputtering using a target in which 0.5 wt% to 5 wt% of tungsten oxide and 0.1 wt% to 1 wt% of zinc oxide are added to indium oxide. In addition, as materials for the anode, 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) can be cited. In addition, a layer formed by laminating them can also be used as the anode. For example, a film in which Al, Ti, and ITSO are sequentially laminated on Ti has high efficiency due to good reflectivity and can achieve a high resolution of several thousand ppi, and thus is preferred. In addition, graphene can also be used as a material for the anode. In addition, by using a composite material that can form the hole injection layer 111 described later for the layer in contact with the anode (typically the hole injection layer), there is no need to consider the work function when selecting the electrode material.

[0225] The hole injection layer 111 is in contact with the anode and has a function of facilitating hole injection into the organic compound layer 103. Phthalocyanine compounds or complexes such as phthalocyanine (abbreviation: H2Pc) and copper phthalocyanine (abbreviation: CuPc) can be used; 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), etc.; or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrene sulfonic acid) (abbreviation: PEDOT / PSS) can be used to form the hole injection layer 111.

[0226] In addition, the hole injection layer 111 may also be composed of a substance having an electron-accepting property. As the substance having an electron-accepting property, an organic compound having an electron-withdrawing group (halogen group, cyano group) can be used, and examples thereof include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloroquinone, 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, compounds such as HAT-CN in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms are thermally stable, and thus are preferred. In addition, [3]axylene derivatives including an electron-withdrawing group (especially a halogen group such as a fluorine group, a cyano group, etc.) have a very high electron-accepting property and are particularly preferred. Specifically, examples thereof include α,α',α''-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzyl cyanide], α,α',α''-1,2,3-cyclopropanetriyl tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzyl cyanide], α,α',α''-1,2,3-cyclopropanetriyl tris[2,3,4,5,6-pentafluorobenzyl cyanide], and the like. As the substance having an electron-accepting property, in addition to the above organic compounds, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used.

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

[0228] As the organic compound having a hole-transporting property for 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. As the organic compound having a hole-transporting property for 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 a hole-transporting property for the composite material is preferably a compound containing a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferred. In addition, as the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least any one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton is preferred, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are further condensed with an aromatic ring or a heteroaromatic ring is preferred.

[0229] In addition, a composite material containing the above-described material having an electron-accepting property and an organic compound having a hole-transporting property effectively causes an interaction between the materials. Therefore, as the spin density measured by the electron spin resonance method (ESR) of the film containing the composite material, the spin density attributable to the signal observed around a g value of 2.00 is preferably 1×10 17 spins / cm 3 or more.

[0230] Such an organic compound having a hole-transporting property preferably has any one 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 including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine including a naphthalene ring, or an aromatic monoamine in which 9-fluorenyl is bonded to the nitrogen of the amine through an arylene group. Note that when these organic compounds having a hole-transporting property are substances including N,N-bis(4-biphenyl)amino, a light-emitting device having a long lifetime can be manufactured, and thus they are preferred.

[0231] As the above-mentioned organic compound having hole-transporting properties, 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-(dibenzothiophen-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'-binaphthalen-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthalen-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthalen-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthalen-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthalen-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthalen-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-(5;2'-binaphthalen-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenyl)-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-fluorene-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-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-4-amine, N,N-Bis(9,9-dimethyl-9H-fluorene-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, etc.

[0232] In addition, as materials with hole-transporting properties, as 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 also be used.

[0233] By forming the hole injection layer 111, the hole injection property can be improved, and thus a light-emitting device with a low driving voltage can be obtained.

[0234] In addition, organic compounds having acceptor properties among substances with electron-accepting properties can be easily formed by vapor deposition, so they are materials that are easy to use.

[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] As the above-mentioned hole-transporting materials, examples 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'-bis(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), etc. Compounds with an aromatic amine backbone;1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-bis(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 with a carbazole skeleton;Compounds with a thiophene backbone such as 4,4’,4”-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-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); and compounds with a furan backbone such as 4,4’,4”-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among them, compounds with an aromatic amine backbone and compounds with a carbazole backbone have high reliability and excellent hole transport properties and contribute to reducing the driving voltage, so they are preferred. Note that as the material constituting the hole transport layer 112, substances listed as hole-transporting materials for the composite material used for the hole injection layer 111 can also be appropriately used.

[0237] The light-emitting layer 113 is a layer containing a light-emitting substance, and preferably contains a light-emitting substance and a host material. Note that the light-emitting layer may also contain other materials. In addition, it may also be a laminate of two layers with different compositions.

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

[0239] In the light-emitting layer, as materials that can be used as fluorescent light-emitting substances, for example, the following substances can be cited. Note that in addition to this, other fluorescent light-emitting substances can also be used.

[0240] Examples include 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'-diphenyldistyrene-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-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butyldiphenylene (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-benzenediamine) (abbreviation: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-benzenediamine (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]vinyl}-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)vinyl]-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)vinyl]-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)vinyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-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)vinyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)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. In particular, fused aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, 1,6BnfAPrn-03 have high hole trapping properties, high luminous efficiency, and high reliability, so they are preferred.,

[0241] In addition, 5,9-diphenyl-5,9-diaza-13b-borata-anthra[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-borata-anthra[3,2,1-de]anthracene-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-bis(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborolo[2,3,4-kl]phenazaborole-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetrakis(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborolo[2,3,4-kl]phenazaborole-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-bis(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborolo[2,3,4-kl]phenazaborole (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 nitrogen- and boron-containing fused heteroaromatic compounds, especially compounds having a diaza-boraza-naphtho-anthracene skeleton have a narrow emission spectrum and can obtain blue light emission with good color purity, and thus can be used appropriately.

[0242] In addition to the above, 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 also be used appropriately.

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

[0244] Examples include: tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviation: [Ir(Mptz)3]) and other organometallic iridium complexes with a 4H-triazole skeleton; tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]) and other organometallic iridium complexes with a 1H-triazole skeleton; 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]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN3}-4-cyanophenyl-κC) (abbreviation: CNImIr) and other organometallic iridium complexes with an imidazole skeleton; tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]) and other organometallic complexes with a benzimidazolylidene skeleton; and 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’ iridium(III) acetylacetonate (abbreviation: FIr(acac)) and other organometallic iridium complexes with a phenylpyridine derivative having an electron-withdrawing group as a ligand. The above substances are compounds that emit blue phosphorescence and are compounds having a luminescence peak in the wavelength region of 450 nm to 520 nm.

[0245] In addition, examples include: tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-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-norbornanyl)-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)]) and other organometallic iridium complexes having a pyridine skeleton; and rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline) terbium(III) (abbreviation: [Tb(acac)3(Phen)]). The above substances are mainly compounds that exhibit green phosphorescence and have a luminescence peak in the wavelength region of 500 nm to 600 nm. In addition, organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they have particularly excellent reliability or luminescence efficiency.

[0246] In addition, examples include: bis[4,6-bis(3-methylphenyl)pyrimidinato](dibenzoylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](di-neopentanoylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalen-1-yl)pyrimidinato](di-neopentanoylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]) and other organometallic iridium complexes having a pyrimidine skeleton; bis(2,3,5-triphenylpyrazinato)(acetylacetonato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(di-neopentanoylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), bis(2,3-bis(4-fluorophenyl)quinoxalinato)(acetylacetonato)iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]) and other organometallic iridium complexes having a pyrazine skeleton; tris(1-phenylisoquinoline-N,C 2’ )iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinoline-N,C 2’ )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), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III) and other organometallic iridium complexes having a pyridine skeleton; platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-thienoyl)-3,3,3-trifluoroacetone](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]). The above substances are compounds that exhibit red phosphorescence and have a luminescence peak in the wavelength region of 600 nm to 700 nm. In addition, organometallic iridium complexes having a pyrazine skeleton can obtain red luminescence with good chromaticity.

[0247] In addition, in addition to the above phosphorescent compounds, known phosphorescent compounds can also be selected and used.

[0248] As TADF materials, fullerenes and their derivatives, acridine and its derivatives, eosin derivatives, etc. can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. can also be cited. As such metal-containing porphyrins, for example, 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. represented by the following structural formulas can also be cited.

[0249] [Chemical formula 20]

[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-dihydroacridin)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), etc., which are heterocyclic compounds having one or both of a π-rich electron heterocyclic ring and a π-deficient electron heterocyclic ring, can also be used. The heterocyclic compound has a π-rich electron heterocyclic ring and a π-deficient electron heterocyclic ring, and has high electron transportability and hole transportability, so it is preferred. Among them, in the skeleton having a π-deficient electron heterocyclic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton) and the triazine skeleton are stable and have good reliability, so they are preferred. In particular, the benzofuranopyrimidine skeleton, the benzothiophenopyrimidine skeleton, the benzofuranopyrazine skeleton and the benzothiophenopyrazine skeleton have high electron accepting properties and good reliability, so they are preferred. In addition, in the skeleton having a π-rich electron heterocyclic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton and the pyrrole skeleton are stable and have good reliability, so it is preferred to have at least one of the above skeletons. In addition, as the furan skeleton, a dibenzofuran skeleton is preferably used, and as the thiophene skeleton, a dibenzothiophene skeleton is preferably used. 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 preferably used. In a substance in which a π-rich electron heterocyclic ring and a π-deficient electron heterocyclic ring are directly bonded, the electron donating property of the π-rich electron heterocyclic ring and the electron accepting property of the π-deficient electron heterocyclic ring are both high, and the energy difference between the S1 energy level and the T1 energy level becomes small, so thermally activated delayed fluorescence can be obtained efficiently, so it is particularly preferred. Note that an aromatic ring bonded with an electron-withdrawing group such as a cyano group can also be used instead of the π-deficient electron heterocyclic ring. In addition, as the π-rich electron skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. can be used.In addition, as the π-deficient electron skeleton, an oxygen 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 or boranthrene, an aromatic ring or heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. can be used. Thus, at least one of the π-deficient electron skeleton and the π-rich electron skeleton can be used in place of the π-deficient electron heteroaromatic ring and the π-rich electron heteroaromatic ring.

[0251] [Chemical formula 21]

[0252] TADF materials refer to materials in which the energy difference between the S1 energy level and the T1 energy level is small and which have the function of converting triplet excitation energy into singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be up-converted into singlet excitation energy (reverse intersystem crossing) by a small amount of thermal energy and singlet excited states can be efficiently generated. In addition, triplet excitation energy can be converted into luminescence.

[0253] An exciplex formed by two substances in the excited state has the function of a TADF material that can convert triplet excitation energy into singlet excitation energy because the energy difference between the S1 energy level and the T1 energy level is extremely small.

[0254] Note that as an index of the T1 energy level, a phosphorescence spectrum observed at low temperature (for example, 77K to 10K) can be used. For TADF materials, preferably, when the wavelength energy of the extrapolated line obtained by drawing a tangent at the tail on the short wavelength side of the fluorescence spectrum is the S1 energy level and the wavelength energy of the extrapolated line obtained by drawing a tangent at the tail on the short wavelength side of the phosphorescence spectrum is the T1 energy level, the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0255] In addition, when a TADF material is used as the luminescent substance, the S1 energy level of the host material is preferably higher than the S1 energy level of the TADF material. In addition, the T1 energy level of the host material is preferably higher than the T1 energy level of the TADF material.

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

[0257] As a material having hole-transporting properties, an organic compound having an amine skeleton, a π-electron-rich heteroaromatic ring skeleton, etc. is preferably used. As the π-electron-rich heteroaromatic ring, a fused aromatic ring containing at least any one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton is preferred, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are further fused with an aromatic ring or a heteroaromatic ring is preferred.

[0258] Such an organic compound having hole-transporting properties preferably has any one 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 including a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine including a naphthalene ring, or an aromatic monoamine in which 9-fluorenyl is bonded to the nitrogen of the amine through an arylene group. Note that when these organic compounds having hole-transporting properties are substances including N,N-bis(4-biphenyl)amino, a light-emitting device having a long lifetime can be manufactured, so they are preferred.

[0259] As such organic compounds, for example, the following can be cited: 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'-bis(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'-bis(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)tris(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenylfluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenylfluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV) and other compounds having a thiophene skeleton; and 4,4',4''-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenylfluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II) and other compounds having a furan skeleton. Among them, the compounds having an aromatic amine skeleton and the compounds having a carbazole skeleton have good reliability and high hole transport properties and contribute to reducing the driving voltage, so they are preferred. In addition, organic compounds cited as examples of hole-transporting materials for the hole-transporting layer can also be used.

[0260] As a material having electron transporting properties, for example, the following are preferably used: beryllium(II) bis(10-hydroxybenzo[h]quinoline) (abbreviation: BeBq2), aluminum(III) bis(2-methyl-8-hydroxyquinoline)(4-phenylphenolate) (abbreviation: BAlq), zinc(II) bis(8-hydroxyquinoline) (abbreviation: Znq), zinc(II) bis[2-(2-benzoxazolyl)phenolate] (abbreviation: ZnPBO), zinc(II) bis[2-(2-benzothiazolyl)phenolate] (abbreviation: ZnBTZ), and other metal complexes, and organic compounds including π-deficient heteroaromatic rings. As the organic compounds including a π-deficient heteroaromatic skeleton, for example, organic compounds including a heteroaromatic ring having an oxazole skeleton, organic compounds including a heteroaromatic ring having a pyridine skeleton, organic compounds including a heteroaromatic ring having a diazine skeleton, and organic compounds including a heteroaromatic ring having a triazine skeleton can be mentioned.

[0261] Among them, organic compounds including a heteroaromatic ring having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds including a heteroaromatic ring having a pyridine skeleton, or organic compounds including a heteroaromatic ring having a triazine skeleton have good reliability, and thus are preferred. In particular, organic compounds including a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds including a heteroaromatic ring having a triazine skeleton have high electron transporting properties, which helps to reduce the driving voltage. In addition, a benzofuranopyrimidine skeleton, a benzothiophenopyrimidine skeleton, a benzofuranopyrazine skeleton, and a benzothiophenopyrazine skeleton have high electron accepting properties and high reliability, and thus are preferred.

[0262] Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-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-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviated as BzOs), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB), bathophenanthroline (abbreviated as Bphen), bathocuproin (abbreviated as BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBphen), 2,2'-(1,3-phenylene)bis( Organic compounds containing a heteroaromatic ring having a pyridine skeleton, such as 2-[4-(9-phenanthrenyl)-1-naphthyl]-1,10-phenanthroline (abbreviation: PnNPhen), 2-[4-(2-triphenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen); 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDB); q-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mCzBPDBq), 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as: 2mPCCzPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mpPCBPDBq), 2-[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(Dibenzothiophen-4-yl)phenyl]dibenz[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(Dibenzothiophen-4-yl)phenyl]dibenz[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-(naphthalen-2-yl)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-(pyridin-3-yl)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 with 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-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-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-pyridyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-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-(Triazin-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-(naphthalen-2-yl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), etc., which are organic compounds containing heteroaromatic rings having a triazine skeleton. In addition, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, or organic compounds containing heteroaromatic rings having a triazine skeleton have high reliability, so they are preferred. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage.

[0263] As the TADF material that can be used as the host material, the same materials as those cited above as TADF materials can be used. When a TADF material is used as the host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing and further energy is transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. At this time, the TADF material is used as the energy donor and the luminescent material is used as the energy acceptor.

[0264] This is very effective when the above-mentioned luminescent material is a fluorescent luminescent material. In addition, at this time, in order to obtain high luminous efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. In addition, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent luminescent material.

[0265] In addition, it is preferable to use a TADF material that emits light overlapping with the wavelength of the absorption band on the lowest energy side of the fluorescent luminescent material. Thus, the excitation energy is smoothly transferred from the TADF material to the fluorescent luminescent material, and luminescence can be obtained efficiently, so it is preferred.

[0266] In order to efficiently generate singlet excitation energy from triplet excitation energy through reverse intersystem crossing, it is preferable to generate carrier recombination in the TADF material. In addition, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent emitter. For this purpose, the fluorescent emitter preferably has a protecting group around the lumophore (the skeleton that causes luminescence) possessed by the fluorescent emitter. As this protecting group, a substituent having no π bond is preferable, and a saturated hydrocarbon is preferable. Specifically, an alkyl group having 3 or more and 10 or less carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 or more and 10 or less carbon atoms, or a trialkylsilyl group having 3 or more and 10 or less carbon atoms can be mentioned. More preferably, it has a plurality of protecting groups. Since the substituent having no π bond has almost no function of transporting carriers, it has almost no influence on carrier transport or carrier recombination, and can keep the lumophore of the TADF material and the fluorescent emitter away from each other. Here, the lumophore refers to the atomic group (skeleton) that causes luminescence in the fluorescent emitter. The lumophore preferably has a π-bonded skeleton, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring. As the above lumophore, for example, a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton, etc. In particular, a fluorescent emitter having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, a naphthobisbenzofuran skeleton has a high fluorescence quantum yield, so it is preferable.

[0267] When a fluorescent luminescent substance is used as the luminescent substance, a material having an anthracene skeleton is preferably used as the host material. By using a substance having an anthracene skeleton as the host material of the fluorescent luminescent substance, a luminescent layer with high luminous efficiency and durability can be achieved. Among the substances having an anthracene skeleton used as the host material, substances having a diphenylanthracene skeleton, especially a 9,10-diphenylanthracene skeleton, are chemically stable, so they are preferred. In addition, when the host material has a carbazole skeleton, the hole injection / transport property is improved, so it is preferred. When a benzocarbazole skeleton in which a benzene ring is fused to carbazole is included, its HOMO level is about 0.1 eV shallower than when a carbazole skeleton is included, and holes are easily injected, so it is more preferred. In particular, when the host material has a dibenzocarbazole skeleton, its HOMO level is about 0.1 eV shallower than when a carbazole skeleton is included, and not only are holes easily injected, but also the hole transport property and heat resistance are improved, so it is preferred. Therefore, a substance further preferably used as the host material is a substance having a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). Note that from the above viewpoint of hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton can also be used instead of the carbazole skeleton. 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-anthryl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[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-anthryl)-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-anthryl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good properties, so they are preferred.

[0268] In addition, the host material may also be a material that mixes multiple substances. When using a mixed host material, it is preferable to mix a material with electron-transporting properties and a material with hole-transporting properties. By mixing a material with electron-transporting properties and a material with hole-transporting properties, it becomes easier to adjust the transport properties of the light-emitting layer 113, and it is also possible to more simply control the recombination region. The weight ratio of the content of the material with hole-transporting properties to the material with electron-transporting properties may be from 1:19 to 19:1.

[0269] Note that, as part of the above-mentioned mixed materials, a phosphorescent light-emitting substance can be used. The phosphorescent light-emitting substance can be used as an energy donor that supplies excitation energy to the fluorescent light-emitting substance when the fluorescent light-emitting substance is used as the light-emitting substance.

[0270] In addition, these mixed materials can also be used to form an exciplex. By selecting the mixed materials in such a way as to form an exciplex that emits light with a wavelength overlapping the absorption band on the lowest energy side of the light-emitting substance, energy transfer can be made smooth, and thus light emission can be obtained efficiently, so it is preferable. In addition, by adopting this structure, the driving voltage can be reduced, so it is preferable.

[0271] Note that at least any one of the materials forming the exciplex can be a phosphorescent light-emitting substance. Thereby, triplet excitation energy can be efficiently converted into singlet excitation energy through reverse intersystem crossing.

[0272] Regarding the combination of materials that efficiently form an exciplex, the HOMO level of the material with hole-transporting properties is preferably higher than the HOMO level of the material with electron-transporting properties. In addition, the LUMO level of the material with hole-transporting properties is preferably higher than the LUMO level of the material with electron-transporting properties. Note that the LUMO level and HOMO level of the material can be obtained from the electrochemical properties (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 hole-transporting material, the emission spectra of an electron-transporting material, and the emission spectra of a mixed film formed by mixing these materials. When a phenomenon where the emission spectrum of the mixed film shifts to the longer wavelength side (or has a new peak on the longer wavelength side) compared to the emission spectra of the respective materials is observed, it indicates the formation of an exciplex. Alternatively, by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film formed by mixing these materials, when a difference in transient response such as an increase in the ratio of a long-lived component or a delayed component in the transient PL lifetime of the mixed film compared to the transient PL lifetimes of the respective materials is observed, it indicates the formation of an exciplex. In addition, the above transient PL can be referred to as transient electroluminescence (EL). In other words, by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film of these materials, and observing the difference in transient response, the formation of an exciplex can be confirmed.

[0274] The electron transport layer 114 is a layer containing a substance having electron-transporting properties. As the material having electron-transporting properties, it is preferably a substance having an electron mobility of 1 × 10 -7 cm 2 / Vs or more when the square root of the electric field strength [V / cm] is 600, and preferably 1 × 10 -6 cm 2 / Vs or more. In addition, as long as the substance has higher electron-transporting properties than hole-transporting properties, substances other than the above can also be used. As the above organic compound, an organic compound containing a π-deficient heteroaromatic ring is preferably used. As the organic compound containing a π-deficient heteroaromatic ring, for example, an organic compound containing a heteroaromatic ring having an oxazole 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, one or more of them are preferably used.

[0275] As the organic compound having electron transporting property that can be used for the above-mentioned electron transport layer 114, the organic compound having electron transporting property in the above-mentioned light-emitting layer 113 and the organic compound exemplified as the second organic compound that can be used for the electron injection layer 115 in Embodiment 1 can be similarly used. Among them, the organic compound containing a heteroaromatic ring having a diazine skeleton, the organic compound containing a heteroaromatic ring having a pyridine skeleton, and the organic compound containing a heteroaromatic ring having a triazine skeleton have good reliability, and thus are preferred. In particular, the organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and the organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transporting property, which helps to reduce the driving voltage. In particular, organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen, and mPPhen2P are preferred, and organic compounds having a phenanthroline dimer structure such as mPPhen2P have excellent stability, and thus are more preferred. In addition, it is preferable to use organic compounds having electron transporting property and high HOMO energy level such as 2mPCCzPDBq and DACT-II, whereby 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 property with an acidity coefficient pK a less than 4.

[0277] Note that the electron transport layer 114 may also have a stacked structure. In addition, when the electron transport layer 114 has a stacked structure, the layer in contact with the light-emitting layer 113 may also be used as a hole blocking layer. When the electron transport layer in contact with the light-emitting layer is used as a hole blocking layer, it is preferable to use a material whose HOMO energy level is deeper than the HOMO energy level of the material contained in the light-emitting layer by 0.5 eV or more.

[0278] An electron injection layer 115 is formed between the electron transport layer 114 and the second electrode 102. The structure of the electron injection layer 115 has been described in detail in Embodiment 1, and thus repeated description is omitted.

[0279] The second electrode 102 is an electrode including a cathode. The second electrode 102 may also have a stacked structure. In this case, the layer in contact with the organic compound layer 103 is used as the cathode. As the material for forming the cathode, metals, alloys, conductive compounds, and mixtures thereof with 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), or strontium (Sr), alloys containing them (MgAg, AlLi), compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), etc.), rare earth metals such as europium (Eu) or ytterbium (Yb), and alloys containing them. However, by providing an electron injection layer 115 or a thin film of the above-mentioned material with a small work function 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 work function size.

[0280] When the second electrode 102 is made of a material having transparency to visible light, a light-emitting device that emits light from the second electrode 102 side can be formed. When the first electrode 101 is made of a material having transparency to visible light, a light-emitting device that emits light from the first electrode 101 side can be formed.

[0281] These conductive materials can be formed by dry methods such as vacuum evaporation, sputtering, inkjet printing, spin coating, etc. In addition, they can also be formed by wet methods such as sol-gel method or wet methods using pastes of metal materials.

[0282] In addition, when it is a top-emission type light-emitting device, the light extraction efficiency can be improved by depositing an organic compound on the second electrode to form a cover layer. The cover layer can be a single-layer structure or a stacked structure. When it is a stacked structure, the light extraction efficiency can be further improved by using organic compounds with different refractive indices respectively.

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

[0284] In addition, the above-mentioned electrodes or layers can also be formed by using different deposition methods.

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

[0286] In Figure 1B , a first light-emitting unit 511 and a second light-emitting unit 512 are stacked 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 Figure 1A the first electrode 101 and the second electrode 102 in Figure 1A , and the same materials as those described in

[0287] The intermediate layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied to the first electrode 501 and the second electrode 502. That is to say, in Figure 1B , when a voltage is applied in such a way that the potential of the anode is higher than the potential of the cathode, the intermediate layer 513 only needs to be a layer that injects electrons into the first light-emitting unit 511 and injects holes into the second light-emitting unit 512.

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

[0289] In addition, the intermediate layer 513 preferably further includes one or both of an electron relay layer 118 and an N-type layer 119 in addition to the P-type layer 117.

[0290] The electron relay layer 118 contains at least a substance with electron transport properties, can prevent the interaction between the N-type layer 119 and the P-type layer 117, and can transfer electrons smoothly. Preferably, the LUMO energy level of the substance with electron transport properties contained in the electron relay layer 118 is set between the LUMO energy level of the acceptor substance in the P-type layer 117 and the LUMO energy level of the substance contained in the layer in the electron transport layer 114 that contacts the intermediate layer 513. Specifically, the LUMO energy level of the substance with electron transport properties in the electron relay layer 118 is -5.0 eV or higher, preferably -5.0 eV or higher and -3.0 eV or lower. In addition, as the substance with electron transport properties in the electron relay layer 118, a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand is preferably used.

[0291] For the N-type layer 119, substances with high electron injection properties such as alkali metals, alkaline earth metals, rare earth metals, and compounds of these substances (alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or compounds of rare earth metals (including oxides, halides, carbonates)) can be used.

[0292] In addition, when the N-type layer 119 contains a substance with electron transport properties and a donor substance, as the donor substance, in addition to alkali metals, alkaline earth metals, rare earth metals, and compounds of these substances (alkali metal compounds (including oxides such as lithium oxide, halides, carbonates such as lithium carbonate and cesium carbonate), alkaline earth metal compounds (including oxides, halides, carbonates), or compounds of rare earth metals (including oxides, halides, carbonates)), organic compounds such as tetrathianaphthacene (abbreviation: TTN), nickelocene, and decamethylnickelocene can also be used. In addition, as the substance with electron transport properties, the same materials as those described above for the electron transport layer 114 can be used.

[0293] Alternatively, in the same position as the N-type layer 119, instead of the N-type layer 119, a layer containing a metal or metal oxide, a first organic compound including a π-deficient heteroaromatic ring, and a second organic compound including two or more heteroaromatic rings that are bonded or fused to each other and include a total of three or more heteroatoms, which was described as a layer used as an electron injection layer in Embodiment 1, can be formed. When adopting this structure, a tandem light-emitting device with good characteristics can also be manufactured.

[0294] When the surface on the anode side of the light-emitting unit is in contact with the intermediate layer 513, the charge generation layer of the intermediate layer 513 can also function as the hole injection layer of the light-emitting unit, so the light-emitting unit may not be provided with a hole injection layer. When the surface on the cathode side of the light-emitting unit is in contact with the intermediate layer 513, the intermediate layer 513 can also function as the electron injection layer of the light-emitting unit, so the light-emitting unit may not be provided with an electron injection layer.

[0295] Although a light-emitting device having two light-emitting units is described in Figure 1B , a light-emitting device in which three or more light-emitting units are stacked can be similarly applied. As the light-emitting device according to the present embodiment, by separating and arranging a plurality of light-emitting units with the intermediate layer 513 between a pair of electrodes, an element can be realized which can achieve high-brightness light emission while maintaining a low current density and has a long lifespan. In addition, a light-emitting device capable of low-voltage driving and low power consumption can be realized.

[0296] In addition, by making the light-emitting colors of the respective light-emitting units different, light emission of a desired color can be obtained from the entire light-emitting device. For example, by obtaining red and green light-emitting colors from a first light-emitting unit and a blue light-emitting color from a second light-emitting unit in a light-emitting device having two light-emitting units, a light-emitting device that emits white light throughout can be obtained.

[0297] In addition, each layer and electrode such as the above-mentioned 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 methods such as evaporation (including vacuum evaporation), droplet ejection (also called inkjet), coating, and gravure printing. In addition, it may include low molecular materials, medium molecular materials (including oligomers, dendrimers), or high molecular materials.

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

[0299] The light-emitting device 130a includes an organic compound layer 103a between a first electrode 101a on an insulating layer 175 and a second electrode 102 opposite to the first electrode 101a. Although the organic compound layer 103a is shown to have a structure 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, the organic compound layer 103a may also have a stacked structure different from the above structure.

[0300] The light-emitting device 130b includes an organic compound layer 103b between a first electrode 101b on an insulating layer 175 and a second electrode 102 opposite to the first electrode 101b. Although the organic compound layer 103b is shown to have a structure 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, the organic compound layer 103b may also have a stacked structure different from the above structure.

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

[0302] The second electrode 102 is preferably a continuous layer shared by the light-emitting device 130a and the light-emitting device 130b. In addition, the organic compound layer 103a and the organic compound layer 103b are processed by photolithography after forming the electron injection layer 115a and after forming the electron injection layer 115b, respectively, so they are independent of each other. A light-emitting device according to one aspect of the present invention can obtain a light-emitting device with good characteristics even when processed by photolithography after forming the electron injection layer 115a and after forming the electron injection layer 115b, respectively. In addition, as Figure 5A shown, the electron injection layer 115a and the electron injection layer 115b may also be a continuous layer shared by the light-emitting device 130a and the light-emitting device 130b.

[0303] In addition, the end portions (contours) of the organic compound layer 103a are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate. In addition, the end portions (contours) of the organic compound layer 103b are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate.

[0304] In addition, due to processing by photolithography, there is a gap d between the organic compound layer 103a and the organic compound layer 103b. In addition, by processing the organic compound layer by photolithography, the distance between the first electrode 101a and the first electrode 101b can be made smaller than that distance during mask evaporation, and it can be 0.5 μm or more and 5 μm or less.

[0305] Figure 4B is a diagram of two adjacent series-connected light-emitting elements (light-emitting devices 130c, 130d) manufactured by photolithography.

[0306] The light-emitting device 130c includes an organic compound layer 103c between a first electrode 101c and a second electrode 102 on an 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 stacked with an intermediate layer 116c therebetween. Note that, although Figure 4B an example in which two light-emitting units are stacked is shown, three or more light-emitting units may also be stacked. The first light-emitting unit 501c includes 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 includes a P-type layer 117c, an electron relay layer 118c, and an N-type layer 119c. Regardless of the presence or absence of the electron relay layer 118c. The second light-emitting unit 502c includes 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 includes 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 stacked with an intermediate layer 116d therebetween. Note that, although Figure 4B an example in which two light-emitting units are stacked is shown, three or more light-emitting units may also be stacked. 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. Regardless of the presence or absence of the electron relay layer 118d. 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 structure described in Embodiment 1.

[0309] The second electrode 102 is preferably a continuous layer shared by the light-emitting device 130c and the light-emitting device 130d. In addition, since the organic compound layer 103c and the organic compound layer 103d are processed by photolithography after forming the electron injection layer 115c and after forming the electron injection layer 115d, respectively, they are independent of each other. A light-emitting device according to one embodiment of the present invention can obtain a light-emitting device having good characteristics even when processed by photolithography after forming the electron injection layer 115c and after forming the electron injection layer 115d, respectively. In addition, as Figure 5BAs shown, the electron injection layers 115c and 115d may also be continuous layers shared by the light-emitting devices 130c and 130d.

[0310] In addition, the ends (contours) of the organic compound layer 103c are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate. In addition, the ends (contours) of the organic compound layer 103d are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate.

[0311] In addition, due to the processing by photolithography, there is a gap d between the organic compound layer 103c and the organic compound layer 103d. In addition, by processing the organic compound layer using photolithography, the distance between the first electrode 101c and the first electrode 101d can be made smaller than that distance during mask evaporation, and it can be made 0.5 μm or more and 5 μm or less.

[0312] The light-emitting device according to one embodiment of the present invention processes the organic compound layer by photolithography, can be processed with sufficient precision, and thus a high-definition display device can be manufactured. In addition, since the photolithography process can be performed on the electron injection layer far from the light-emitting layer without being contaminated by alkali metals, a light-emitting device with good characteristics can be realized. As described above, the light-emitting device according to one embodiment of the present invention having the above structure can realize a high-definition display device and a light-emitting device with good characteristics.

[0313] In addition, since the organic compound layers of the light-emitting device according to one embodiment of the present invention are processed simultaneously by photolithography, the contours of the layers included in the organic compound layer are substantially aligned. Here, "substantially aligned" in this specification means that the difference between the contour A of layer A and the contour 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 contour of the part being compared. In addition, when the end face of the organic compound layer has a tapered shape, continuous change of the contour is allowed.

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

[0315] Embodiment 3 As Fig. 6A and Figure 6B shown, a plurality of light-emitting devices 130 are formed on the insulating layer 175 to constitute a display device. In this embodiment, a display device according to one embodiment of the present invention will be described in detail.

[0316] The display device 100 includes 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, the term "sub-pixel 110" is sometimes used to describe the common content among sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B. Additionally, regarding other constituent elements differentiated by letters, the reference numerals omitting the letters are sometimes used to describe the common content among those constituent elements.

[0318] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. Thus, an image can be displayed on pixel portion 177. Note that in this embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are taken as examples for description, and sub-pixels of other colors can also be combined. Additionally, the number of sub-pixels is not limited to three and can be four or more. As four sub-pixels, for example, there can be mentioned: sub-pixels of four colors, R, G, B, and white (W); sub-pixels of four colors, R, G, B, and Y; and sub-pixels of four colors, R, G, B, and infrared light (IR); etc.

[0319] In this specification and the like, the row direction is sometimes denoted as the X direction and the column direction is denoted as the Y direction. The X direction intersects with the Y direction, for example, perpendicularly.

[0320] In Fig. 6A In the example shown, sub-pixels of different colors are arranged and configured in the X direction, and sub-pixels of the same color are arranged and configured in the Y direction. Note that sub-pixels of different colors can also be arranged and configured in the Y direction, and sub-pixels of the same color can be arranged and configured in the X direction.

[0321] A connection portion 140 is provided outside pixel portion 177, and an area 141 can also be provided. For example, area 141 is provided between pixel portion 177 and connection portion 140. An organic compound layer 103 is provided in area 141. Additionally, a conductive layer 151C is provided in connection portion 140.

[0322] In Fig. 6A In the example shown, area 141 and connection portion 140 are located on the right side of pixel portion 177, but there is no particular limitation on the positions of area 141 and connection portion 140. Furthermore, area 141 and connection portion 140 can also be one or more.

[0323] Figure 6B is an example of a cross-sectional view along the dash-dot line A1 - A2 in Fig. 6A As Figure 6BAs shown, 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 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 disposed on a substrate (not shown). The insulating layer 175, the insulating layer 174, and the insulating layer 173 are provided with openings reaching the conductive layer 172, and plugs 176 are disposed in such a manner as to be embedded in the openings.

[0324] In the pixel portion 177, a light-emitting device 130 is disposed on the insulating layer 175 and the plugs 176. A protective layer 131 is disposed so as to cover the light-emitting device 130. The substrate 120 is bonded to the protective layer 131 by a resin layer 122. In addition, it is preferable to provide an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 between adjacent light-emitting devices 130.

[0325] Figure 6B Cross-sections of a plurality of inorganic insulating layers 125 and a plurality of insulating layers 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 formed as continuous single layers, respectively. That is, the inorganic insulating layer 125 and the insulating layer 127 are preferably insulating layers having openings in the first electrode.

[0326] Figure 6B Light-emitting devices 130R, 130G, and 130B are shown as the light-emitting device 130. The light-emitting colors of the light-emitting devices 130R, 130G, and 130B are different 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. In addition, the light-emitting device 130R, the light-emitting device 130G, or the light-emitting device 130B can also emit other visible light or infrared light.

[0327] A display device according to one embodiment of the present invention can have, for example, a top emission structure that emits light in a direction opposite to the substrate on which the light-emitting device is formed. In addition, a display device according to one embodiment of the present invention can also have a bottom emission structure.

[0328] Examples of the light-emitting substance contained 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). In addition, inorganic compounds such as quantum dots can also be used.

[0329] The light-emitting device 130R has the structure as shown in Embodiment 1, including 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. The common layer 104 may or may not be provided. However, when the common layer 104 is provided, damage to the organic compound layer 103R during processing can be reduced, so it is preferred. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. In addition, when the common layer 104 is provided, the stacked structure of the organic compound layer 103R and the common layer 104 is equivalent to the organic compound layer 103 in Embodiment 2.

[0330] The light-emitting device 130G has the structure as shown in Embodiment 1, including 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. The common layer 104 may or may not be provided. However, when the common layer 104 is provided, damage to the organic compound layer 103G during processing can be reduced, so it is preferred. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. In addition, when the common layer 104 is provided, the stacked structure of the organic compound layer 103G and the common layer 104 is equivalent to the organic compound layer 103 in Embodiment 2.

[0331] The light-emitting device 130B has the structure as shown in Embodiment 1, including 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. The common layer 104 may or may not be provided. However, when the common layer 104 is provided, damage to the organic compound layer 103B during processing can be reduced, so it is preferred. When the common layer 104 is provided, the common layer 104 is preferably an electron injection layer. In addition, when the common layer 104 is provided, the stacked structure of the organic compound layer 103B and the common layer 104 is equivalent to the organic compound layer 103 in Embodiment 2.

[0332] One of the pixel electrode and the common electrode included in the light-emitting device is used as the anode, and the other is used as the cathode. Hereinafter, unless otherwise specified, the description will be made on the premise that the pixel electrode is used as the anode and the common electrode is used as the cathode.

[0333] The organic compound layers 103R, 103G, and 103B are independently formed in an island shape for each light-emitting device or for each light-emitting color. By forming the organic compound layer 103 in an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can also be suppressed in the high-definition display device. Thereby, crosstalk can be suppressed, and a display device with extremely high contrast can be achieved. In particular, a display device with high current efficiency at low brightness can be achieved.

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

[0335] In addition, in the display device according to one embodiment of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in Figure 6B the example shown, the first electrode of the light-emitting device 130 has a stacked structure of a conductive layer 151 and a conductive layer 152. For example, when the display device 100 has a top-emission structure and the pixel electrode of the light-emitting device 130 is used as an anode, preferably, the conductive layer 151 is a layer with a high visible light reflectance, and the conductive layer 152 is, for example, a layer with visible light transmissivity and a large work function. When the display device 100 has a top-emission structure, the higher the visible light reflectance of the pixel electrode, the higher the light extraction efficiency of the light emitted from the organic compound layer 103. In addition, when the pixel electrode is used as an anode, the larger the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. Thereby, by the pixel electrode of the light-emitting device 130 having a stacked structure of a conductive layer 151 with a high visible light reflectance and a conductive layer 152 with a large work function, the light-emitting device 130 can be 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 visible light reflectance, the visible light reflectance of the conductive layer 151 is, for example, preferably 40% or more and 100% or less, or 70% or more and 100% or less. In addition, when the conductive layer 152 is an electrode with visible light transmissivity, the visible light transmittance is, for example, preferably 40% or more.

[0337] Here, when the pixel electrode has a stacked structure of multiple layers, the pixel electrode is deteriorated, for example, due to the reaction between the multiple layers. For example, when removing the film formed after forming the pixel electrode by a wet etching method, galvanic corrosion occurs due to the contact of the chemical solution with the pixel electrode.

[0338] In view of this, in the display device 100 of the present embodiment, an insulating layer 156 is formed so as to cover the side surfaces of the conductive layer 151 and the conductive layer 152. Thus, for example, even when removing the film formed after forming the pixel electrode including the conductive layer 151 and the conductive layer 152 using a wet etching method, the liquid medicine can be prevented from contacting the conductive layer 151. Therefore, for example, galvanic corrosion occurring in the pixel electrode can be suppressed. Therefore, the display device 100 can be manufactured by a method with a high yield, so an inexpensive display device can be realized. In addition, the occurrence of defects in the display device 100 can be suppressed, so 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 obtained by appropriately combining them can also be used.

[0340] As the conductive layer 152, an oxide containing 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 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, the work function of indium tin oxide containing silicon is relatively large, for example, 4.0 eV or more, so it can be suitably used as the conductive layer 152.

[0341] The conductive layer 151 and the conductive layer 152 may each have a laminated structure including a plurality of layers containing different materials. In this case, the conductive layer 151 may include a layer using a material such as a conductive oxide that can be used for the conductive layer 152, and the conductive layer 152 may include a layer using a material such as a metal material that can be used for the conductive layer 151. 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 may 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 also have a tapered shape. Specifically, when the end portion of the insulating layer 156 has a tapered shape with a taper angle less than 90°, the coverage of the structure provided along the side surface of the insulating layer 156 can be improved.

[0343] Fig. 7A It is a view when the conductive layer 151 has a laminated structure including a plurality of layers containing different materials. As Fig. 7AAs shown, the conductive layer 151 includes 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, Fig. 7A the shown conductive layer 151 has a three-layer stacked structure. Thus, in the case where the conductive layer 151 has a stacked structure of multiple layers, it is sufficient that the visible light reflectance of at least one of the layers constituting the conductive layer 151 is higher than the visible light reflectance of the conductive layer 152.

[0344] In Fig. 7A the shown example, the conductive layer 151b is sandwiched between the conductive layer 151a and the conductive layer 151c. The conductive layer 151a and the conductive layer 151c can use materials that are less likely to deteriorate compared to the conductive layer 151b. For example, the conductive layer 151a can use a material that is less likely to undergo migration due to contact with the insulating layer 175 compared to the conductive layer 151b. In addition, the conductive layer 151c can use a material that is less likely to be oxidized compared to the conductive layer 151b; and the resistivity of its oxide is lower than the resistivity of the oxide of the material used for the conductive layer 151b.

[0345] Thus, by adopting the structure in which the conductive layer 151b is sandwiched between the conductive layer 151a and the conductive layer 151c, the selection range of the material of the conductive layer 151b can be expanded. Thereby, for example, the conductive layer 151b can be made into a layer having a visible light reflectance higher 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. In addition, an aluminum-containing alloy can also be used as the conductive layer 151b. In addition, titanium can be used as the conductive layer 151a. Although the visible light reflectance of titanium is lower than that of aluminum, it is less likely to undergo migration compared to aluminum even when in contact with the insulating layer 175. And, titanium can be used as the conductive layer 151c. Although the visible light reflectance of titanium is lower than that of aluminum, it is less likely to be oxidized compared to aluminum and the resistivity of its oxide is lower than the resistivity of aluminum oxide.

[0346] In addition, silver or a silver-containing alloy can also be used as the conductive layer 151c. Silver has the property of having a higher visible light reflectivity than titanium. Furthermore, silver has the following properties: it is less likely to be oxidized compared to aluminum, and the resistivity of silver oxide is lower than that of aluminum oxide. Thus, when silver or a silver-containing alloy is used as the conductive layer 151c, the visible light reflectivity of the conductive layer 151 can be appropriately increased while suppressing an increase in the resistance of the pixel electrode due to the oxidation of the conductive layer 151b. Here, as the silver-containing alloy, for example, an alloy of silver, palladium, and copper (Ag-Pd-Cu, also denoted as APC) can be used. In addition, when silver or a silver-containing alloy is used as the conductive layer 151c and aluminum is used as the conductive layer 151b, the visible light reflectivity of the conductive layer 151c can be increased compared to the visible light reflectivity of the conductive layer 151b. Here, silver or a silver-containing alloy can also be used as the conductive layer 151b. In addition, silver or a silver-containing alloy can also be used as the conductive layer 151a.

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

[0348] Thus, by making the conductive layer 151 have a stacked structure of multiple 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 the light-emitting device 130 adopts a microcavity structure, by using silver or a silver-containing alloy, which is a material with a high visible light reflectivity, as the conductive layer 151c, the light extraction efficiency of the display device 100 can be appropriately 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 less than 90°. For example, in Fig. 7A the conductive layer 151 having the structure shown, it is preferable that the side surface of at least one of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c has a tapered shape.

[0351] Fig. 7AThe conductive layer 151 shown can be formed by lithography. Specifically, first, a conductive film that will become the conductive layer 151a, a conductive film that will become the conductive layer 151b, and a conductive film that will become the conductive layer 151c are sequentially deposited. Next, a resist mask is formed on the conductive film that will become the conductive layer 151c. Then, for example, by an etching method, the conductive film in the region that does not overlap with the resist mask is removed. Here, by processing the conductive film under conditions where the resist mask is more likely to retreat (shrink) compared to the case where the conductive layer 151 is formed with a non-tapered shape (i.e., vertical sides), a conductive layer 151 with tapered sides can be formed.

[0352] Here, when processing the conductive film under conditions where the resist mask is likely to retreat (shrink), the conductive film is sometimes likely to be processed in the horizontal direction. In other words, the isotropy of etching is sometimes higher compared to the case where the conductive layer 151 is formed with vertical sides.

[0353] In addition, when the conductive layer 151 has a stacked structure of multiple layers made of different materials, the processability in the horizontal direction of these multiple layers is sometimes different. For example, the processability in the horizontal direction of the conductive layer 151a, the conductive layer 151b, and the conductive layer 151c is sometimes different.

[0354] In this case, sometimes after processing the conductive film, as Fig. 7A shown, a protrusion is formed with the side surface of the conductive layer 151b located inside the side surfaces of the conductive layer 151a and the conductive layer 151c. As a result, there is a concern that the coverage of the conductive layer 152 over the conductive layer 151 is reduced and disconnection of the conductive layer 152 occurs.

[0355] In view of this, it is preferable to provide the insulating layer 156 as Fig. 7A shown. Fig. 7A An example is shown in which the insulating layer 156 is provided on the conductive layer 151a in a manner that has a region overlapping with the side surface of the conductive layer 151b. Thereby, disconnection or thinning of the conductive layer 152 due to the protrusion can be suppressed, and thus connection failure or an increase in drive voltage can be suppressed.

[0356] Note that although Fig. 7A shows a structure in which the entire side surface of the conductive layer 151b is covered by the insulating layer 156, a part of the side surface of the conductive layer 151b may not be covered by the insulating layer 156. The same applies to the pixel electrode having the structure shown below, and a part of the side surface of the conductive layer 151b may not be covered by the insulating layer 156.

[0357] When the conductive layer 151 has Fig. 7AWhen the structure shown is used, the conductive layer 152 covers the conductive layers 151a, 151b, 151c, and the insulating layer 156 and is electrically connected to the conductive layers 151a, 151b, and 151c. Thus, for example, when removing the film deposited after forming the conductive layer 152 by a wet etching method, the liquid medicine does not come into contact with the conductive layers 151a, 151b, and 151c. Therefore, corrosion occurring in the conductive layers 151a, 151b, and 151c can be suppressed. Therefore, the display device 100 can be manufactured by a method with a high yield. In addition, the occurrence of defects can be suppressed, and thus a display device 100 with high reliability can be realized.

[0358] Here, as Fig. 7A shown, the insulating layer 156 preferably has a curved surface. Thus, for example, disconnection occurring in the conductive layer 152 covering the insulating layer 156 can be suppressed as compared with the case where it is perpendicular to the side surface of the insulating layer 156 (parallel to the Z direction). In addition, when the side surface of the insulating layer 156 has a tapered shape, specifically, a tapered shape with a taper angle less than 90°, for example, disconnection occurring in the conductive layer 152 covering the insulating layer 156 can be suppressed as compared with the case where it is perpendicular to the side surface of the insulating layer 156. Thus, the display device 100 can be manufactured by a method with a high yield. In addition, the occurrence of defects is suppressed, and the display device 100 can be made into a display device with high reliability.

[0359] Note that Fig. 7A A structure 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 embodiment of the present invention is not limited thereto. For example, the side surface of the conductive layer 151b may also be located outside the side surface of the conductive layer 151a. In addition, the side surface of the conductive layer 151b may also be located outside the side surface of the conductive layer 151c.

[0360] FIG. 7B to FIG. 7D Another structure of the first electrode 101 is shown. Figure 7B Shown in Fig. 7A In the first electrode 101, a structure is shown in which the insulating layer 156 covers the side surfaces of the conductive layers 151a, 151b, and 151c in addition to the side surface of the conductive layer 151b.

[0361] Figure 7C Shown in Fig. 7A In the first electrode 101, a structure is shown in which the insulating layer 156 is not provided.

[0362] Fig.7D Shown is a structure in which Fig. 7A In the first electrode 101, the conductive layer 151 does not have a stacked structure and the conductive layer 152 has a stacked structure.

[0363] The conductive layer 152a is a layer with a closer adhesion to the conductive layer 152b, for example, higher than that of the insulating layer 175. As the conductive layer 152a, for example, an oxide containing 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 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. Thereby, film peeling of the conductive layer 152b can be suppressed. In addition, the conductive layer 152b can be made not to contact the insulating layer 175.

[0364] The conductive layer 152b is a layer with a higher visible light reflectance (for example, the reflectance of light at a specified wavelength in the range of 400 nm or more and less than 750 nm) than the conductive layer 151, the conductive layer 152a, and the conductive layer 152c. The visible light reflectance of the conductive layer 152b 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. In addition, as the conductive layer 152b, for example, a material with a visible light reflectance higher than that of aluminum can be used. Specifically, for example, silver or a silver-containing alloy can be used as the conductive layer 152b. As the silver-containing alloy, for example, an alloy of silver, palladium, and copper (APC) can be cited. Thereby, the display device 100 can be made into a display device with high light extraction efficiency. Note that a metal other than silver can also be used as the conductive layer 152b.

[0365] When the conductive layer 151 and the conductive layer 152 are used as anodes, the conductive layer 152c is preferably a layer with a large work function. The conductive layer 152c is, for example, a layer with a work function larger than that of the conductive layer 152b. As the conductive layer 152c, for example, the same material as that which can be used for the conductive layer 152a can be used. For example, the same material can be 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] Note that when the conductive layer 151 and the conductive layer 152 are used as cathodes, the conductive layer 152c is preferably a layer with a small work function. The conductive layer 152c is, for example, a layer with a work function smaller than that of the conductive layer 152b.

[0367] In addition, the conductive layer 152c is preferably a layer with a high visible light transmittance (e.g., the transmittance of light with a specified wavelength in the range of more than 400 nm and less than 750 nm). For example, the visible light transmittance of the conductive layer 152c is preferably higher than that of the conductive layer 151 and the conductive layer 152b. For example, the visible light transmittance of the conductive layer 152c 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. Thereby, the light emitted from the organic compound layer 103 and absorbed by the conductive layer 152c can be reduced. In addition, as described above, the conductive layer 152b under the conductive layer 152c can be a layer with a high visible light reflectance. Therefore, the display device 100 can be made into a display device with high light extraction efficiency.

[0368] Next, with reference to FIG. 8A to FIG. 13C An example of the manufacturing method of the display device 100 having the Fig. 6A shown structure will be described. The organic compound layer of the light-emitting device included in the display device 100 is formed through a manufacturing process including water treatment. By using the organic compound of one embodiment of the present invention for the organic layer of the light-emitting device included in the display device of one embodiment of the present invention, problems such as dissolution of the layer including the organic compound and penetration of the liquid medicine into the layer using the organic compound can be prevented even when manufactured by a manufacturing method including water treatment, and thus a light-emitting device with 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 by sputtering, chemical vapor deposition (CVD: Chemical Vapor Deposition), vacuum evaporation, pulsed laser deposition (PLD: Pulsed Laser Deposition), or ALD methods. As the CVD method, there are plasma-enhanced chemical vapor deposition (PECVD: Plasma Enhanced CVD) method and thermal CVD method. In addition, as one of the thermal CVD methods, there is metal organic chemical vapor deposition (MOCVD: Metal Organic CVD) method.

[0370] In addition, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by wet deposition methods such as spin coating, dipping, spraying, inkjet, dispenser, screen printing, offset printing, doctor knife method, slot coating, roll coating, curtain coating, or knife-over-edge coating.

[0371] In particular, when manufacturing a light-emitting device, vacuum processes such as evaporation methods and solution processes such as spin coating and inkjet printing can be utilized. As evaporation methods, physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam evaporation, molecular beam epitaxy, and vacuum evaporation, and chemical vapor deposition (CVD) methods can be cited. In particular, methods such as evaporation (such as vacuum evaporation), coating (dip coating, dye coating, bar coating, spin coating, spray coating), and printing (inkjet printing, screen printing (stencil printing), offset printing (lithography), flexographic printing (letterpress printing), gravure printing, or microcontact printing) can be used to form functional layers (such as hole injection layers, hole transport layers, hole blocking layers, light-emitting layers, electron blocking layers, electron transport layers, and electron injection layers) included in the organic compound layer.

[0372] In addition, when processing a thin film constituting a display device, for example, photolithography can be used for processing. Alternatively, nanoimprinting, sandblasting, peeling, etc. can be used to process the thin film. In addition, island-shaped thin films can be directly formed by a deposition method using a masking mask such as a metal mask.

[0373] As photolithography, for example, lithography can be used. Typically, there are the following two methods of lithography. One is a method of forming a resist mask on a thin film to be processed, processing the thin film by etching, for example, and removing the resist mask. The other is a method of forming a photosensitive thin film and then performing exposure and development to process the thin film into a desired shape.

[0374] In lithography, 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 lights can be used. In addition, ultraviolet light, KrF laser, ArF laser, etc. can also be used. In addition, immersion exposure technology can be used for exposure. In addition, as the light used for exposure, extreme ultraviolet (EUV) light or X-rays can also be used. In addition, instead of the light used for exposure, an electron beam can also be used. When using extreme ultraviolet light, X-rays, or an electron beam, extremely fine processing can be performed, so it is preferred. In addition, when exposure is performed by scanning a light beam such as an electron beam, a photomask is not required.

[0375] In the etching of a thin film, dry etching, wet etching, sandblasting, etc. can be used.

[0376] First, as Fig. 8AAn insulating layer 171 is formed on a substrate (not shown). Next, 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. Next, 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 at least heat resistance capable of withstanding the subsequent heat treatment can be used. In the case of using an insulating substrate 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. In addition, a single-crystal semiconductor substrate or a polycrystalline semiconductor substrate made of silicon or silicon carbide, a compound semiconductor substrate made of silicon germanium, an SOI substrate, or the like can also be used as the semiconductor substrate.

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

[0379] Next, as Fig. 8A shown, a conductive film 151f that will later become the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, and the conductive layer 151C is formed on the plug 176 and the insulating layer 175. The conductive film 151f can be formed, for example, by a sputtering method or a vacuum evaporation method. In addition, a metal material can be used as the conductive film 151f, for example.

[0380] Next, as Fig. 8A shown, a conductive film 152f that will later become the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C is formed on the conductive film 151f. The conductive film 152f can be formed, for example, by a sputtering method or a vacuum evaporation method. In addition, a conductive oxide can be used as the conductive film 152f, for example. Alternatively, a laminated structure of a film using a metal material and a film using a conductive oxide on the film can be adopted as the conductive film 152f. For example, a laminated structure of a film using titanium, silver, or a silver-containing alloy and a film using a conductive oxide on the film can be adopted as the conductive film 152f.

[0381] In addition, the conductive film 152f can be formed by ALD method. Here, as the conductive film 152f, an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. At this time, by repeating the cycle with the introduction of a precursor (which is generally sometimes referred to as a precursor or a metal precursor, etc.), the purge of this precursor, the introduction of an oxidant (which is generally sometimes referred to as a reactant, a reactant, or a non-metal precursor, etc.), and the purge of this oxidant as one cycle, the conductive film 152f can be formed. Here, when forming an oxide film containing multiple metals such as indium tin oxide as the conductive film 152f, the metal composition can be controlled by changing the number of cycles according to the type of precursor.

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

[0383] In addition, for example, in the case of depositing a zinc oxide film as the conductive film 152f, a Zn-O film is formed by the above process. In addition, for example, in the case of depositing an aluminum zinc oxide film as the conductive film 152f, a Zn-O film and an Al-O film are formed by the above process. In addition, for example, in the case of depositing a titanium oxide film as the conductive film 152f, a Ti-O film is formed by the above process. In addition, for example, in the case of depositing 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 process. In addition, for example, in the case of depositing a zinc oxide film containing gallium, a Ga-O film and a Zn-O film are formed by the above process.

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

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

[0386] Next, as Figure 8B shown, for example, using an etching method, specifically a dry etching method, the conductive film 151f and the conductive film 152f in the regions not overlapping with the resist mask 191 are removed, thereby forming pixel electrodes including the conductive layer 151 and the conductive layer 152. Note that, in the case where the conductive film 151f includes a layer using a conductive oxide such as indium tin oxide, the layer can also be removed using a wet etching method. Thereby, the conductive layer 151 and the conductive layer 152 are formed. Note that, for example, in the case of removing a part of the conductive film 151f using a dry etching method, recesses may be formed in the region of the insulating layer 175 that does not overlap with the conductive layer 151.

[0387] Note that, after processing the conductive film 152f using lithography to form the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C, the conductive film 151f can 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 the resist mask, a part of the conductive film 152f is removed using an etching method. For example, the conductive film 152f can be removed using a wet etching method. Note that the conductive film 152f can also be removed using a dry etching method. Then, it is preferable to remove the conductive film 151f using a wet etching method.

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

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

[0390] Next, next, as Fig.8DAs shown, an insulating film 156f that will later become insulating layers 156R, 156G, 156B, and 156C is formed on conductive layers 151R and 152R, conductive layers 151G and 152G, conductive layers 151B and 152B, conductive layers 151C and 152C, and insulating layer 175. The insulating film 156f can be formed, for example, by CVD method, ALD method, sputtering method, or vacuum evaporation method.

[0391] The insulating film 156f can use an inorganic material. 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 nitrogen oxide 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 nitrogen oxide insulating film containing silicon can be used. For example, silicon oxynitride can be used as the insulating film 156f.

[0392] Next, as Fig. 8E shown, the insulating film 156f is processed to form insulating layers 156R, 156G, 156B, and 156C. For example, by etching the top surface of the insulating film 156f substantially uniformly, the insulating layer 156 can be formed. The process of etching uniformly like this for planarization is also called etch-back process. In addition, the insulating layer 156 can also be formed using lithography technology.

[0393] Next, as Fig.9A shown, an organic compound film 103Rf that will later become an organic compound layer 103R is formed on conductive layers 152R, 152G, 152B, insulating layers 156R, 156G, 156B, and insulating layer 175.

[0394] As Fig.9A shown, the organic compound film 103Rf is not formed on the conductive layer 152C. For example, by using a mask for defining the deposition range (also called a region mask or a coarse metal mask, etc. to distinguish from a high-precision metal mask), the organic compound film 103Rf can be deposited only in the desired region. By adopting a deposition process using a region 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 evaporation method, specifically by vacuum evaporation method. In addition, the organic compound film 103Rf can also be formed by methods such as transfer method, printing method, inkjet method, and coating method.

[0396] Next, as Fig.9AAs shown, 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, the conductive layer 152C, and the insulating layer 175.

[0397] Note that, in the present embodiment, an example in which the mask film is composed of a two-layer structure of the sacrificial film 158Rf and the mask film 159Rf is shown, but the mask film may have a single-layer structure or a stacked structure of three or more layers.

[0398] By providing the 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] As 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. As the mask film 159Rf, a film with a large etching selectivity ratio with respect to the sacrificial film 158Rf is used.

[0400] In addition, 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. The substrate temperature when forming the sacrificial film 158Rf and the sacrificial film 159Rf is typically 200°C or lower, preferably 150°C or lower, more preferably 120°C or lower, further preferably 100°C or lower, and even more preferably 80°C or lower.

[0401] As the sacrificial film 158Rf and the mask film 159Rf, a film that can be removed by wet etching is preferably used. By using wet etching, 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 dry etching.

[0402] The sacrificial film 158Rf and the mask film 159Rf can be formed, for example, by sputtering, ALD (thermal ALD, PEALD), CVD, or vacuum evaporation. In addition, they can also be formed by the above-mentioned wet deposition methods.

[0403] The sacrificial film 158Rf formed in contact with the organic compound film 103Rf is preferably formed by a forming method that causes less damage to the organic compound film 103Rf compared to when forming the mask film 159Rf. For example, compared to sputtering, it is more preferable to use ALD or vacuum evaporation to form the sacrificial film 158Rf.

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

[0405] As the sacrificial film 158Rf and the mask film 159Rf, 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 such metal materials can be used respectively. Low melting point materials such as aluminum or silver are particularly preferably used. By using a metal material capable of shielding ultraviolet rays as one or both of the sacrificial film 158Rf and the mask film 159Rf, irradiation of ultraviolet rays to the organic compound film 103Rf can be suppressed, and deterioration of the organic compound film 103Rf can be suppressed, so it is preferable.

[0406] In addition, as the sacrificial film 158Rf and the mask film 159Rf, metal oxides such as In-Ga-Zn oxide, indium oxide, In-Zn oxide, In-Sn oxide, indium titanium oxide (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), or indium tin oxide containing silicon, etc. can be used respectively.

[0407] Note that the above gallium can also be replaced by an element M (M is one or more of aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium).

[0408] In addition, as the sacrificial film and the mask film, a film containing a material having light-shielding properties, particularly ultraviolet light-shielding properties, is preferably used. As the light-shielding material, various materials such as a metal, an insulator, a semiconductor, and a semimetal having ultraviolet light-shielding properties can be used. Since a part or all of the sacrificial film and the mask film will be removed in a later process, the sacrificial film and the mask film are preferably films that can be processed by etching, and particularly preferably films with good processability.

[0409] When a semiconductor material such as silicon or germanium is used as the sacrificial film and the mask film, for example, the affinity of this material for the semiconductor manufacturing process is high, so it is preferable. Alternatively, an oxide or nitride of the above semiconductor material can be used. Alternatively, a non-metal material such as carbon or its compound can be used. In addition, a metal such as titanium, tantalum, tungsten, chromium, aluminum, or an alloy containing one or more of them can be used. In addition, 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] In addition, by using a film made of a material having ultraviolet light-shielding properties as a sacrificial film or a mask film, for example, ultraviolet light can be prevented from irradiating the organic compound layer in the exposure process. By suppressing the damage to the organic compound layer caused by ultraviolet light, the reliability of the light-emitting device can be improved.

[0411] Note that the same effect is also produced when the film containing the material having ultraviolet light-shielding properties is used as the material of the inorganic insulating film 125f described later.

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

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

[0414] In addition, the same inorganic insulating film can be used for both the sacrificial layer 158Rf and the inorganic insulating layer 125 to be formed later. For example, an alumina film formed by ALD method can be used for both the sacrificial layer 158Rf and the inorganic insulating layer 125. Here, the sacrificial layer 158Rf and the inorganic insulating layer 125 can be deposited under the same deposition conditions or different deposition conditions. For example, by depositing the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, an insulating layer with high barrier properties against at least one of water and oxygen can be formed as the sacrificial film 158Rf. On the other hand, since most or all of the sacrificial film 158Rf will be removed in later processes, it is preferably easy to process. Therefore, the sacrificial layer 158Rf is preferably deposited under conditions with a lower substrate temperature than the inorganic insulating layer 125 during deposition.

[0415] As one or both of the sacrificial film 158Rf and the mask film 159Rf, an organic material may also be used. For example, as the organic material, a material that is soluble in a solvent that is at least chemically stable to the film located at the uppermost part of the organic compound film 103Rf may be used. In particular, a material that is soluble in water or alcohol may be appropriately used. When depositing the above material, preferably, the material is applied by a wet deposition method in a state where the material is dissolved in a solvent such as water or alcohol, and then a heat treatment for evaporating the solvent is performed. At this time, it is preferable to perform the heat treatment in a reduced-pressure atmosphere, whereby the solvent can be removed at a low temperature and in a short time, and the thermal damage to the organic compound film 103Rf can be reduced.

[0416] As the sacrificial film 158Rf and the mask film 159Rf, organic resins such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, a polyamide resin soluble in alcohol, or a fluororesin such as a perfluoropolymer may also be used.

[0417] For example, as the sacrificial film 158Rf, an organic film (e.g., a PVA film) formed by any one of vapor deposition and the above wet deposition method may be used, and as the mask film 159Rf, an inorganic film (e.g., a silicon nitride film) formed by sputtering may be used.

[0418] Next, as shown in Fig.9A 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 can use a positive resist material or a negative resist material.

[0420] The resist mask 190R is provided at a position overlapping the conductive layer 152R. The resist mask 190R is preferably also provided at a position overlapping the conductive layer 152C. Thereby, damage to the conductive layer 152C during the manufacturing process of the display device can be suppressed. Note that the resist mask 190R may not be provided on the conductive layer 152C. In addition, as shown in the cross-sectional view along B1 - B2 in Fig.9A the resist mask 190R is preferably provided so as to cover 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] Next, as shown in Fig. 9BAs shown, a part of the mask film 159Rf is removed using a resist mask 190R to form a mask layer 159R. The mask layer 159R remains on the conductive layer 152R and the conductive layer 152C. Then, the resist mask 190R is removed. Next, the mask layer 159R is used as a mask (also referred to as a hard mask) to remove a part of the sacrificial film 158Rf to form a sacrificial layer 158R.

[0422] The sacrificial film 158Rf and the mask film 159Rf can be processed by a wet etching method or a dry etching method, respectively. 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, compared with the case of using the dry etching method, the damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced. When using the wet etching method, for example, it is preferable to use a developing solution, an aqueous solution of tetramethylammonium hydroxide (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a liquid medicine such as a mixed liquid thereof.

[0424] Since the organic compound film 103Rf is not exposed during the processing of the mask film 159Rf, the range of selection of the processing method is wider compared with the case of processing the sacrificial film 158Rf. Specifically, when processing the mask film 159Rf, even if an oxygen-containing gas is used as the etching gas, the deterioration of the organic compound film 103Rf can be suppressed.

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

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

[0427] The resist mask 190R can be removed by the same method as the resist mask 191. The resist mask 190R can be removed, for example, by ashing using oxygen plasma. Alternatively, oxygen gas and CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or a Group 18 element such as He can also be used. Alternatively, the resist mask 190R can 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 choices for the method of removing the resist mask 190R can be expanded.

[0428] Next, as Fig. 9B shown, 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 hard masks to remove a part of the organic compound film 103Rf to form the organic compound layer 103R.

[0429] Thus, as Fig. 9B shown, 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. 9B An example is shown in which the end of the organic compound layer 103R is located outside the end of the conductive layer 152R. By adopting this structure, miniaturization of the pixel can be achieved, and a high-definition display can be manufactured. Note that although not shown in Fig. 9B , recesses may sometimes be formed in the region of the insulating layer 175 that does not overlap with the organic compound layer 103R due to the above-described etching process.

[0431] As described above, the resist mask 190R is preferably provided so as to cover 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 B1 - B2. Thus, as Fig. 9B shown, the sacrificial layer 158R and the mask layer 159R are provided so as to cover 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 lines B1 - B2. Therefore, exposure of the insulating layer 175, for example, between B1 - B2 can be suppressed. As a result, removal of a part of the insulating layer 175, the insulating layer 174, and the insulating layer 173 by etching or the like, which may cause the conductive layer 179 to be exposed, can be suppressed. Therefore, unintentional electrical connection of the conductive layer 179 to other conductive layers can be suppressed. For example, a short circuit between the conductive layer 179 and the common electrode 155 to be formed in a later process can be suppressed.

[0432] Preferably, the organic compound film 103Rf is processed using anisotropic etching. Particularly preferably, anisotropic dry etching is used. Alternatively, wet etching may also be used.

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

[0434] In addition, an oxygen-containing gas may also be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low-power conditions while maintaining a sufficient etching rate. Therefore, damage to the organic compound film 103Rf can be suppressed. Also, defects such as adhesion of reaction products generated during etching can be suppressed.

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

[0436] As described above, in one aspect of the present invention, a mask layer 159R is formed by forming a resist mask 190R on the mask film 159Rf and removing a part of the mask film 159Rf using the resist mask 190R. Then, an organic compound layer 103R is formed by using the mask layer 159R as a mask to remove a part of the organic compound film 103Rf. Therefore, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using lithography. In addition, a part of the organic compound film 103Rf may be removed using the resist mask 190R. Then, the resist mask 190R may also 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 sometimes becomes hydrophilic. By performing the hydrophobization treatment on the conductive layer 152G, for example, the adhesion between the conductive layer 152G and the layer (here, the organic compound layer 103G) to be formed in a later process can be improved to suppress film peeling. Note that the hydrophobization treatment may not be performed.

[0438] Next, as Fig. 10AAs shown, an organic compound film 103Gf which will later become the organic compound layer 103G is formed on the conductive layer 152G, the conductive layer 152B, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159R, and the insulating layer 175.

[0439] The organic compound film 103Gf can be formed in the same manner as the method that can be used when forming the organic compound film 103Rf. Additionally, the organic compound film 103Gf can have the same structure as the organic compound film 103Rf.

[0440] Next, as Fig. 10A shown, 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 the mask layer 159R. Then, a resist mask 190G is formed. The materials and formation methods of the sacrificial film 158Gf and the mask film 159Gf are the same as the conditions that can be used for the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods of the resist mask 190G are the same as the conditions that can be applied to the resist mask 190R.

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

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

[0443] Thus, as Fig. 10B shown, a stacked structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G. In addition, 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 sometimes becomes hydrophilic. By performing the hydrophobization treatment on the conductive layer 152B, for example, the adhesion with the layer (here, the organic compound layer 103B) that will be formed in the subsequent process can be improved to suppress film peeling. Note that the hydrophobization treatment may not be performed.

[0445] Next, as Fig. 10C shown, an organic compound film 103Bf which will later become the organic compound layer 103B is formed on the conductive layer 152B, the mask layer 159R, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159G, and the insulating layer 175.

[0446] The organic compound film 103Bf can be formed in the same manner as the method that can be used when forming the organic compound film 103Rf. In addition, the organic compound film 103Bf can have the same structure as the organic compound film 103Rf.

[0447] Next, as Fig. 10C shown, a sacrificial film 158Bf which will later become the sacrificial layer 158B and a mask film 159Bf which will later become the mask layer 159B are sequentially formed on the organic compound film 103Bf and the mask layer 159R. Then, 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 that can be used for 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 that can be applied to the resist mask 190R.

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

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

[0450] Thus, as Fig. 10D shown, a stacked structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. In addition, the mask layer 159R and the mask layer 159G are exposed.

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

[0452] As described above, the distance between two adjacent organic compound layers among the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B formed using lithography technology can be reduced to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, for example, this distance can be defined based on the distance between the opposing ends of two adjacent organic compound layers among the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In this way, by reducing the distance between the island-shaped organic compound layers, a display device with high clarity and a large aperture ratio can be provided. In addition, the distance between the first electrodes of adjacent light-emitting devices can also be reduced, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less. In addition, the distance between the first electrodes of adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0453] Next, as Fig.11A shown, 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 prevent the mask layer 159R, the mask layer 159G, and the mask layer 159B from remaining 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] Note that although the case of removing the mask layer 159R, the mask layer 159G, and the mask layer 159B is described as an example in this embodiment, it is also possible not to remove the mask layer 159R, the mask layer 159G, and the mask layer 159B. For example, when the mask layer 159R, the mask layer 159G, and the mask layer 159B contain the above-mentioned material having ultraviolet light-shielding properties, it is preferable to enter the next process without removing the above mask layer to protect the organic compound layer from ultraviolet light.

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

[0456] Alternatively, the mask layer can also be removed by dissolving it in a solvent such as water or alcohol. Examples of the alcohol include ethanol, methanol, isopropyl alcohol (IPA), or glycerol.

[0457] After removing the mask layer, a drying process can also 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, a heat treatment can also be performed in an inert gas atmosphere or a reduced-pressure atmosphere. 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, and more preferably 70°C or higher and 120°C or lower. By using a reduced-pressure atmosphere, drying can be performed at a lower temperature, so it is preferred.

[0458] Next, as Fig. 11B shown, 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 described later, an insulating film that will later become the insulating layer 127 is formed so as to contact the top surface of the inorganic insulating film 125f. Therefore, the top surface of the inorganic insulating film 125f preferably has high affinity with the material for this insulating film (for example, a photosensitive resin composition containing an acrylic resin). To improve this affinity, a surface treatment can also be performed to hydrophobize (or increase its hydrophobicity) the top surface of the inorganic insulating film 125f. For example, it is preferred to perform a treatment using a silylating agent such as hexamethyldisilazane (HMDS). By hydrophobizing the top surface of the inorganic insulating film 125f in this way, the insulating film 127f can be formed with high adhesion. In addition, as the surface treatment, the above-described hydrophobization treatment can also be performed.

[0460] Next, as Fig. 11C shown, 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 deposited 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. In particular, since the inorganic insulating film 125f is formed so as to contact the sides of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, the inorganic insulating film 125f is preferably deposited 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 when depositing the insulating film 127f.

[0462] In addition, the inorganic insulating film 125f and the insulating film 127f are each formed at a temperature lower than the heat-resistant temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. By increasing the substrate temperature during deposition, an inorganic insulating film 125f with a low impurity concentration and a high barrier property against at least one of water and oxygen can be formed even if its thickness is thin.

[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.

[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 substrate temperature range.

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

[0466] In addition to this, the inorganic insulating film 125f can also be formed by a sputtering method, a CVD method, or a PECVD method with a deposition rate higher than that of the ALD method. Thereby, a display device with high reliability can be manufactured with high productivity.

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

[0468] For example, it is preferable to form the insulating film 127f using a resin composition containing 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 by irradiating light and a compound that generates an acid by heating can be used. The resin composition may further contain one or more of a photosensitizer, a sensitizer, a catalyst, an adhesion aid, a surfactant, and an antioxidant.

[0469] In addition, it is preferable to perform a heat treatment (also referred to as pre-baking) after forming the insulating film 127f. This heat treatment is performed at a temperature lower than the heat-resistant 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 still more preferably 70°C or higher and 120°C or lower. Thereby, the solvent in the insulating film 127f can be removed.

[0470] Next, exposure is performed to expose a part of the insulating film 127f with 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 to the region where the insulating layer 127 will not be formed in the subsequent process. The insulating layer 127 is formed in the region sandwiched by any two of the conductive layers 152R, the conductive layer 152G, and the conductive layer 152B, and around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated to the conductive layers 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 to the region where the insulating layer 127 will be formed.

[0471] By means of the exposed region of the insulating film 127f, the width of the insulating layer 127 to be formed later can be controlled. In the present embodiment, processing is performed such that the insulating layer 127 has a portion overlapping the top surface of the conductive layer 151.

[0472] The light used for exposure preferably has an i-line (wavelength 365 nm). In addition, the light used for exposure may also have at least one of a g-line (wavelength 436 nm) and an h-line (wavelength 405 nm).

[0473] Here, by providing an oxygen barrier insulating layer (such as an alumina film or the like) 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, oxygen diffusion into the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be suppressed. When light (visible light or ultraviolet light) is irradiated onto the organic compound layer, sometimes the organic compound contained in the organic compound layer becomes excited and promotes reaction with oxygen in the atmosphere. Specifically, when light (visible light or ultraviolet light) is irradiated onto the organic compound layer in an oxygen-containing atmosphere, oxygen may bond 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, oxygen in the atmosphere can be suppressed from bonding to the organic compound contained in the organic compound layer.

[0474] Next, as Fig. 12AAs shown, the exposed area in the insulating film 127f is removed by development to form the insulating layer 127a. The insulating layer 127a is formed in the area sandwiched by any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B and the area surrounding the conductive layer 152C. Here, in the case of using an acrylic resin for the insulating film 127f, an alkaline solution, such as TMAH, can be used as a developer.

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

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

[0477] Then, if Fig. 12B As shown, the insulating layer 127a is used as a mask to perform etching to remove a portion of the inorganic insulating film 125f, thereby reducing the thickness of a portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, the inorganic insulating layer 125 is formed under the insulating layer 127a. In addition, the surface of the portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B with a smaller thickness is exposed. Hereinafter, the etching process using the insulating layer 127a as a mask is sometimes referred to as the first etching process.

[0478] The first etching process can be performed by dry etching or wet etching. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the first etching process can be performed at once, which is preferable.

[0479] By using the insulating layer 127 a having tapered side surfaces as a mask for etching, the side surfaces of the inorganic insulating layer 125 and the upper end portions of the side surfaces of the sacrificial layers 158R, 158G, and 158B can be easily tapered.

[0480] When dry etching is performed, chlorine-based gas is preferably used. As the chlorine-based gas, one gas selected from Cl2, BCl3, SiCl4, and CCl4, or a mixture of two or more of the above gases, can be used. In addition, one gas selected from oxygen gas, hydrogen gas, helium gas, and argon gas, or a mixture of two or more of the above gases, can be appropriately added to the above chlorine-based gas. By utilizing dry etching, regions where the thickness of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B is small can be formed with excellent in-plane uniformity.

[0481] As a dry etching device, a dry etching device having a high-density plasma source can be used. For example, as a dry etching device having a high-density plasma source, for example, an inductively coupled plasma (ICP: Inductively Coupled Plasma) etching device can be used. Alternatively, a capacitively coupled plasma (CCP: Capacitively Coupled Plasma) etching device including parallel plate electrodes can be used. The capacitively coupled plasma etching device including parallel plate electrodes can also adopt a structure in which a high-frequency voltage is applied to one of the parallel plate electrodes. Alternatively, a structure in which multiple different high-frequency voltages are applied to one of the parallel plate electrodes can also be adopted. Alternatively, a structure in which a high-frequency voltage with the same frequency is applied to each of the parallel plate electrodes can also be adopted. Alternatively, a structure in which high-frequency voltages with different frequencies are applied to each of the parallel plate electrodes can also be adopted.

[0482] In addition, when dry etching is performed, byproducts generated during dry etching may be deposited on the top surface and side surfaces of the insulating layer 127a. As a result, components in the etching gas, components in the inorganic insulating film 125f, components in the sacrificial layers 158R, 158G, and 158B may be included in the insulating layer 127 after the display device is completed.

[0483] In addition, it is preferred to perform the first etching process using 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 further 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, an alkaline solution, can be used in the wet etching of the aluminum oxide film. At this time, wet etching can be performed in a glue coating manner. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the above-mentioned etching process can be performed at one time, so it is preferred.

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

[0485] Next, the entire substrate is preferably exposed to visible light or ultraviolet light to irradiate the insulating layer 127a. The energy density of this exposure is preferably higher than 0 mJ / cm 2and is 800 mJ / cm 2 Hereinafter, it is more preferably higher than 0 mJ / cm 2 and is 500 mJ / cm 2 Hereinafter. By performing such exposure after development, the transparency of the insulating layer 127a can sometimes be improved. In addition, sometimes the substrate temperature required for the heat treatment for deforming the insulating layer 127a into a tapered shape in the subsequent process can be reduced.

[0486] Here, by providing an oxygen barrier insulating layer (such as an alumina film or the like) as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, oxygen diffusion into the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be suppressed. When light (visible light or ultraviolet light) is irradiated onto the organic compound layer, sometimes the organic compounds contained in the organic compound layer become excited states and promote reactions with oxygen in the atmosphere. Specifically, when light (visible light or ultraviolet light) is irradiated onto the organic compound layer in an oxygen-containing atmosphere, oxygen may bond to the organic compounds contained in the organic compound layer. By providing the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B on the island-shaped organic compound layer, oxygen in the atmosphere can be suppressed from bonding to the organic compounds contained in the organic compound layer.

[0487] Next, a heat treatment (also referred to as post-baking) is performed. By performing the heat treatment, the insulating layer 127a can be deformed into an insulating layer 127 having a tapered shape on its side surface ( Fig. 12C ). This heat treatment is performed at a temperature lower than the heat-resistant 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, and more preferably 70°C or higher and 130°C or lower. The heating atmosphere can be either an air atmosphere or an inert gas. In addition, the heating atmosphere can be either an air atmosphere or a reduced-pressure atmosphere. In the heat treatment of this step, it is preferable to increase the substrate temperature compared to the heat treatment (pre-baking) after forming 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, by not completely removing the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B and leaving the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B in a state where the thickness is thinned, damage and deterioration of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be prevented during this heat treatment. Thereby, the reliability of the light-emitting device can be improved.

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

[0490] Next, as Fig.13A shown, an etching process is performed using the insulating layer 127 as a mask 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 is sometimes also removed. As a result, openings are respectively formed in the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Hereinafter, the etching process using the insulating layer 127 as a mask is sometimes referred to as the second etching process.

[0491] The end portion of the inorganic insulating layer 125 is covered by the insulating layer 127. In addition, Fig.13A an example is shown in which a part of the end portion of the sacrificial layer 158G (specifically, the conical shape portion formed by the first etching process) is covered by the insulating layer 127 and the conical shape portion formed by the second etching process is exposed.

[0492] When the first etching process is not performed and the etching process of the inorganic insulating layer 125 and the mask layer is performed at once after the post-baking, voids are sometimes formed due to side etching such that the inorganic insulating layer 125 and the mask layer under the end portion of the insulating layer 127 disappear. Due to these voids, irregularities are generated on the surface where the common electrode 155 is formed, and disconnection is likely to occur in the common electrode 155. Even if voids are formed due to side etching of the inorganic insulating layer 125 and the mask layer after the first etching process, these voids can be filled by the insulating layer 127 through the subsequent post-baking. Then, in the second etching process, the mask layer with a further reduced thickness is etched, so the amount of side etching is small, voids are not easily formed, and the voids that can be formed can also be extremely small. Therefore, the surface where the common electrode 155 is formed can be made flatter.

[0493] The insulating layer 127 may also cover the entire end portion of the sacrificial layer 158G. For example, the end portion of the insulating layer 127 sometimes droops to cover the end portion of the sacrificial layer 158G. In addition, for example, the end portion of the insulating layer 127 sometimes contacts the top 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 insulating layer 127a after development is not exposed, the shape of the insulating layer 127 is sometimes likely to change.

[0494] The second etching process is performed using 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. The wet etching can be performed using an alkaline solution such as TMAH.

[0495] On the other hand, when the second etching process is performed using the wet etching method, if there are gaps at the interfaces between the organic compound layer 103 and the sacrificial layer 158, between the organic compound layer 103 and the inorganic insulating layer 125, and between the organic compound layer 103 and the insulating layer 175 due to problems such as the adhesion between the organic compound layer 103 and other layers, the chemical solution used in the second etching process sometimes enters these gaps and contacts the pixel electrode. Here, when the chemical solution contacts both the conductive layer 151 and the conductive layer 152, sometimes the conductive layer with the lower natural potential of the conductive layer 151 and the conductive layer 152 corrodes due to galvanic corrosion. For example, when aluminum is used as the conductive layer 151 and indium tin oxide is used as the conductive layer 152, sometimes the conductive layer 152 corrodes. As a result, the yield of the display device sometimes decreases. In addition, the reliability of the display device sometimes decreases.

[0496] As described above, by forming the insulating layer 156 so as to have a region overlapping with 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, disconnection of the inorganic insulating layer 125 can be prevented. Therefore, for example, it is possible to prevent the chemical solution from contacting the underlying structure such as the conductive layer 151 during the second etching process. 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, between each light-emitting device, it is possible to suppress poor connection due to disconnection in the common electrode 155 and resistance increase due to a portion with a locally thin thickness. Thereby, the display device according to one embodiment of the present invention can improve the display quality.

[0498] In addition, a heat treatment may be performed after a part of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B is exposed. By this heat treatment, water contained in each organic compound layer and water adsorbed on the surface of each organic compound layer can be removed. In addition, the shape of the insulating layer 127 sometimes changes due to this heat treatment. Specifically, the insulating layer 127 sometimes expands so as to cover at least one of the end portion of the inorganic insulating layer 125, the end portions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surface of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B.

[0499] When the temperature of the heat treatment is too low, water contained in each organic compound layer and water adsorbed on the surface of each organic compound layer cannot be removed. In addition, when 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 sometimes occur. Therefore, the heat treatment temperature is preferably higher than the temperature at which water is released 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 more preferably lower than the glass transition temperature of the organic compound contained in the top surface of the organic compound layer 103. Specifically, the substrate temperature is preferably 80°C or higher and 130°C or lower, more preferably 90°C or higher and 120°C or lower, further preferably 100°C or higher and 120°C or lower, and still further preferably 100°C or higher and 110°C or lower. The heating atmosphere can be either an air atmosphere or an inert gas. Note that the heating atmosphere can be an atmospheric pressure atmosphere or a reduced pressure atmosphere, and a reduced pressure atmosphere is preferably used to prevent re-adsorption of the water released from the organic compound layer 103.

[0500] Through 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 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, deterioration of the characteristics of the light-emitting device can be prevented.

[0501] Next, as Fig. 13B shown, 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 a method such as sputtering or vacuum evaporation. Alternatively, the common layer 104 can be formed by evaporation and the common electrode 155 can be formed by sputtering.

[0502] Next, as Fig. 13C shown, a protective layer 131 is formed on the common electrode 155. The protective layer 131 can be formed by a method such as vacuum evaporation, sputtering, CVD, or ALD.

[0503] Next, the substrate 120 is bonded to the protective layer 131 using the resin layer 122, whereby a display device can be manufactured. As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the insulating layer 156 is provided on the sides of the conductive layer 151 and the conductive layer 152. Thereby, the yield of the display device can be improved and the occurrence of defects can be suppressed.

[0504] As described above, in the method for manufacturing a display device according to one embodiment 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 high-precision metal mask but are formed by depositing a film on one surface and then processing it. Therefore, the island-shaped layers can be formed with a uniform thickness. Moreover, a high-definition display device or a display device with a high aperture ratio can be realized. In addition, even if the definition or aperture ratio is high and the distance between sub-pixels is extremely short, it is possible to suppress the contact between the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B in adjacent sub-pixels. Accordingly, it is possible to suppress the occurrence of leakage current between sub-pixels. Thereby, crosstalk can be prevented and a display device with an extremely high contrast can be realized. In addition, a display device that can have good characteristics even when including a tandem light-emitting device manufactured by a lithography technique can be provided.

[0505] The structure of the present embodiment can be used in appropriate combination with the structures of other embodiments.

[0506] Embodiment 4 In the present embodiment, with reference to FIG. 14A to FIG. 14G and FIG. 15A to FIG. 15I a light-emitting device according to one embodiment of the present invention will be described.

[0507] [Layout of pixels] In the present embodiment, a pixel layout different from Fig. 6A will be mainly described. The arrangement of sub-pixels is not particularly limited, and various arrangement methods can be adopted. As the arrangement of sub-pixels, for example, stripe arrangement, S-stripe arrangement, matrix arrangement, delta arrangement, Bayer arrangement, and Pentile arrangement can be cited.

[0508] In the present embodiment, the top surface shape of the sub-pixels shown in the drawings corresponds to the top surface shape of the light-emitting region.

[0509] In addition, as the top surface shape of the sub-pixels, for example, polygons such as triangles, quadrangles (including rectangles and squares), pentagons, etc., the above-mentioned polygonal shapes with rounded corners, ellipses, or circles can be cited.

[0510] In addition, the circuit layout constituting the sub-pixels is not limited to the range of the sub-pixels shown in the drawings, and can also be arranged outside thereof.

[0511] Fig.14A The pixel 178 shown adopts an S-stripe arrangement. Fig.14A The pixel 178 shown is composed of three sub-pixels: a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0512] Fig. 14BThe pixel 178 shown includes a sub-pixel 110R having a top surface shape of an approximate trapezoid or an approximate triangle with rounded corners, a sub-pixel 110G having a top surface shape of an approximate trapezoid or an approximate triangle with rounded corners, and a sub-pixel 110B having a top surfac...

Claims

1. A light emitting device, comprising: a first electrode; a second electrode; as well as an organic compound layer between the first electrode and the second electrode, Wherein, the organic compound layer includes a light-emitting layer and an electron injection layer, The electron injection layer comprises a metal or a metal oxide, a first organic compound and a second organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound includes two or more heteroaromatic rings, The two or more heteroaromatic rings are bonded to each other or fused and include three or more heteroatoms in total, Furthermore, the second organic compound acts as a multidentate ligand and interacts with the metal or the metal oxide via two or more of the three or more heteroatoms.

2. The light emitting device according to claim 1, The second organic compound interacts with the metal or the metal oxide as a bidentate ligand or a tridentate ligand.

3. The light emitting device according to claim 1, The three or more heteroatoms are all nitrogen atoms.

4. A light emitting device, comprising: a first electrode; a second electrode; as well as an organic compound layer between the first electrode and the second electrode, Wherein, the organic compound layer includes a light-emitting layer and an electron injection layer, The electron injection layer comprises a metal or a metal oxide, a first organic compound and a second organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound is represented by the general formula (G1-1), And, A 1 , A 2 and A 3 and independently represent a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms.

5. A light emitting device, comprising: a first electrode; a second electrode; as well as an organic compound layer between the first electrode and the second electrode, Wherein, the organic compound layer includes a light-emitting layer and an electron injection layer, The electron injection layer comprises a metal or a metal oxide, a first organic compound and a second organic compound, The first organic compound includes a π-electron-deficient heteroaromatic ring, The second organic compound is represented by the general formula (G1-2), A 1 and A 2 independently represent a substituted or unsubstituted heteroaromatic ring having 1 to 30 carbon atoms and, A 1 Contains more than two nitrogen atoms.

6. The light emitting device according to claim 1, The two or more heteroaromatic rings are all π-electron-deficient heteroaromatic rings.

7. The light emitting device according to claim 1, The two or more heteroaromatic rings independently include at least one of a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, a triazine ring, an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring and a triazole ring.

8. The light emitting device according to claim 1, At least one of the two or more heteroaromatic rings comprises a pyrazine ring, a pyrimidine ring, a pyridazine ring or a triazine ring.

9. The light emitting device according to claim 1, The two or more heteroaromatic rings include three or more pyridine rings in total.

10. The light emitting device according to claim 1, The first organic compound has an electron donating group.

11. The light emitting device according to claim 10, The electron-donating group comprises at least one of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group and a heterocyclic amino group.

12. The light emitting device according to claim 1, The acidity coefficient pK of the first organic compound is a 8 or above.

13. The light emitting device according to claim 1, The first organic compound includes a phenanthroline ring.

14. The light emitting device according to claim 1, The glass transition temperature of the second organic compound is g It is above 100°C.

15. The light emitting device according to claim 1, The LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound.

16. The light emitting device according to claim 1, The metal belongs to Group 1, Group 3, Group 11 or Group 13 of the Periodic Table of Elements.

17. The light emitting device according to claim 4, The first organic compound includes a phenanthroline ring.

18. The light emitting device according to claim 4, The LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound.

19. The light emitting device according to claim 4, The metal belongs to Group 1, Group 3, Group 11 or Group 13 of the Periodic Table of Elements.

20. The light emitting device according to claim 5, The first organic compound includes a phenanthroline ring.

21. The light emitting device according to claim 5, The LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound.

22. The light emitting device according to claim 5, The metal belongs to Group 1, Group 3, Group 11 or Group 13 of the Periodic Table of Elements.

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