Light emitting device

Abstract

Provided is a light-emitting device having good reliability. Provided is a light emitting device including a first insulating layer, a first electrode formed on the first insulating layer, a second electrode, and an organic compound layer located between the first electrode and the second electrode, the outline of the second electrode substantially coinciding with the outline of the organic compound layer, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer includes a metal or an oxide of the metal, a first organic compound including a first pi-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound including a second pi-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound containing a second p-electron-deficient heteroaromatic ring, and the LUMO level of the second organic compound is 0.20 eV or more lower than the LUMO level of the first organic compound.

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, a semiconductor device, a display device, a light-emitting device, a power storage device, a storage device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), and a driving method or a manufacturing method 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 conducted on a home television device (also referred to as a television or a television receiver), digital signage, a public information display (PID), etc., and as uses of small display devices, research and development have been conducted on a smartphone or a tablet terminal having a touch panel.

[0004] At the same time, high definition of display devices has also been advanced. As devices that require high-definition display devices, for example, research and development have been conducted on devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR).

[0005] As a display element for a display device, development of a light-emitting device (also referred to as a light-emitting element) has been increasingly active. A light-emitting device (also referred to as an EL device or an EL element) using an electroluminescence (hereinafter referred to as EL) phenomenon, particularly an organic EL device mainly using an organic compound, has the following characteristics: it is easy to achieve thinness and light weight; it can respond to an input signal 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. The organic EL device has a structure including an organic compound layer (also referred to as an EL layer) having a light-emitting layer between a pair of electrodes.

[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 having an interval of several μm between organic compound layers can be obtained (for example, refer to Patent Document 1).

[0007] [Patent Document 1] Japanese PCT International Application Translation, Gazette No. 2018-521459 [Patent Document 2] International Patent Application Publication No. 2021 / 045178 SUMMARY OF THE INVENTION

[0008] In the case of organic EL devices (also referred to as light-emitting devices in this specification), it has been known that the initial characteristics or reliability of the cathode and the organic compound layer are affected when exposed to atmospheric components such as water and oxygen. Therefore, in common practice, the cathode and the organic compound layer are processed in an inert atmosphere or an atmosphere close to a vacuum. In particular, in many cases, an electron injection layer uses an alkali metal, an alkaline earth metal, or a compound thereof. These metals and compounds have a very high reactivity with water or oxygen. When the surface of the organic compound 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-described process of processing by photolithography, it is inevitable to expose the EL device 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] In addition, one of the objects 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 a low driving voltage and manufactured through a photolithography process. Another object of one aspect of the present invention is to provide a light-emitting device having a low manufacturing cost, a low driving voltage, and manufactured through a photolithography process. Another object of one aspect of the present invention is to provide a light-emitting device having good reliability and manufactured through a photolithography process. Another object of one aspect of the present invention is to provide a light-emitting device having a low manufacturing cost and good reliability and 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 and manufactured through a photolithography process. Another object of one aspect of the present invention is to provide a light-emitting device having a low manufacturing cost, good luminous efficiency, and reliability and manufactured through a photolithography process.

[0012] In addition, one of the objects of one embodiment of the present invention is to provide a novel light-emitting device that can be used in a high-definition display device. In addition, one of the objects of one embodiment of the present invention is to provide a light-emitting device having good efficiency that can be used in a high-definition display device. In addition, one of the objects of one embodiment of the present invention is to provide a light-emitting device with good reliability that can be used in a high-definition display device. In addition, one of the objects of one embodiment of the present invention is to provide a light-emitting device having good luminous efficiency and reliability that can be used in a high-definition display device.

[0013] In addition, one of the objects of one embodiment of the present invention is to provide a display device with high reliability. In addition, one of the objects of one embodiment of the present invention is to provide a high-definition display device. In addition, one of the objects of one embodiment 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 can be extracted from the descriptions in the specification, drawings, and claims.

[0015] One embodiment of the present invention is a light-emitting device formed on a first insulating layer and including: a first electrode; a second electrode; and an organic compound layer. The first electrode is formed in contact with the first insulating layer, the organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from at least one of other multiple light-emitting devices adjacent to the light-emitting device. When viewed from a direction substantially perpendicular to the surface of the first insulating layer on which the first electrode is formed, the contour of the second electrode substantially coincides with the contour of the organic compound layer. 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 is an organic compound containing a first π-deficient heteroaromatic ring having an electron-donating group, and the second organic compound is an organic compound containing a second π-deficient heteroaromatic ring. Moreover, the LUMO energy level of the second organic compound is 0.20 eV or more lower than the LUMO energy level of the first organic compound.

[0016] In addition, another aspect of the present invention is a light-emitting device formed on a first insulating layer, and includes: a first electrode; a second electrode; and an organic compound layer. The first electrode is formed in contact with the first insulating layer, the organic compound layer is located between the first electrode and the second electrode, the second electrode and the organic compound layer are separated from at least one of other multiple light-emitting devices adjacent to the light-emitting device. When viewed from a direction substantially perpendicular to the surface of the first insulating layer on which the first electrode is formed, the contour of the second electrode substantially coincides with the contour of the organic compound. The organic compound layer includes a light-emitting layer and an electron injection layer, and the electron injection layer has a stacked structure including a first layer containing a metal and a second layer containing a first organic compound and a second organic compound. The first layer is located closer to the cathode side than the second layer. The first organic compound is an organic compound containing a first π-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound containing a second π-deficient heteroaromatic ring, and the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by 0.20 eV or more.

[0017] Another aspect of the present invention is a light-emitting device having the above structure, wherein the organic compound layer includes a P-type layer between the electron injection layer and the second electrode, and the P-type layer contains a fifth organic compound having hole-transporting properties and a sixth organic compound containing at least one of a halogen group and a cyano group or a second metal oxide.

[0018] In addition, another aspect of the present invention is a light-emitting device which is one of multiple light-emitting devices included in a light-emitting device group including a first electrode group formed on the same insulating surface, a second electrode group opposite 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 includes a first electrode, a second electrode, and a first layer. The first electrode is one of the first electrode group, and the first electrode is independent in each of the multiple light-emitting devices. The first layer is one of the first layer group, and the first layer is independent in each of the multiple light-emitting devices. The second electrode is one of the second electrode group, and the second electrode is independent in each of the multiple light-emitting devices. The second electrode and the first layer overlap with 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 is an organic compound containing a first π-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound containing a second π-deficient heteroaromatic ring, and the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by 0.20 eV or more. The interval between the first layer in this light-emitting device and the first layer in other light-emitting devices adjacent to this light-emitting device is 0.5 μm or more and 5 μm or less.

[0019] Further, another aspect 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 including a first electrode group formed on the same insulating surface, a second electrode group opposite 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 includes a first electrode, a second electrode, and a first layer. The first electrode is one of the first electrode group, the first electrode is independent in each of the plurality of light-emitting devices, the first layer is one of the first layer group, the first layer is independent in each of the plurality of light-emitting devices, the second electrode is one of the second electrode group, the second electrode is independent in each of the plurality of light-emitting devices, the second electrode and the first layer overlap with the first electrode. The first layer includes a light-emitting layer and an electron injection layer. The electron injection layer has a stacked structure including a first layer containing a metal and a second layer containing a first organic compound and a second organic compound. The first layer is closer to the cathode side than the second layer. The first organic compound is an organic compound containing a first π-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound containing a second π-deficient heteroaromatic ring. The LUMO energy level of the second organic compound is 0.20 eV or more lower than the LUMO energy level of the first organic compound. The interval between the first layer in this light-emitting device and the first layer in other light-emitting devices adjacent to this light-emitting device is 0.5 μm or more and 5 μm or less.

[0020] Further, another aspect of the present invention is a light-emitting device having the above structure, in which when the LUMO energy level of the first organic compound is LUMO1 (eV), the LUMO energy level (LUMO2 (eV)) of the second organic compound satisfies LUMO1 - 0.80 ≤ LUMO2 ≤ LUMO1 - 0.20.

[0021] Further, another aspect of the present invention is a light-emitting device having the above structure, in which when the LUMO energy level of the first organic compound is LUMO1 (eV), the LUMO energy level (LUMO2 (eV)) of the second organic compound satisfies LUMO1 - 0.80 ≤ LUMO2 ≤ LUMO1 - 0.30.

[0022] Further, another aspect of the present invention is a light-emitting device having the above structure, in which the first layer includes a P-type layer between the electron injection layer and the second electrode. The P-type layer contains a fifth organic compound having hole-transporting properties and a sixth organic compound containing at least one of a halogen group and a cyano group or a second metal oxide.

[0023] Further, another aspect of the present invention is a light-emitting device having the above structure, in which when viewed from a direction substantially perpendicular to the insulating surface, the contour of the second electrode substantially coincides with the contour of the first layer.

[0024] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the end of the cross-section of the second electrode and the end of the cross-section of the first layer are substantially aligned in a direction substantially perpendicular to the insulating surface.

[0025] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the first π-deficient heteroaromatic ring is a heteroaromatic ring containing two or more pyridine rings.

[0026] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the acidity coefficient pK of the first organic compound a is 8 or more.

[0027] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the first π-deficient heteroaromatic ring and the second π-deficient heteroaromatic ring are different from each other.

[0028] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the second organic compound has an oxazole ring (imidazole ring, pyrazole ring, oxazole ring, thiazole ring), a triazole ring, a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), or a triazine ring.

[0029] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the acidity coefficient pK of the second organic compound a is less than 4.

[0030] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the light-emitting layer contains a third organic compound, and the third organic compound contains a third π-deficient heteroaromatic ring, and the third π-deficient heteroaromatic ring is the same as the second π-deficient heteroaromatic ring.

[0031] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the light-emitting layer contains a third organic compound, and the third organic compound is the same organic compound as the second organic compound.

[0032] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which an electron transport layer is included between the light-emitting layer and the electron injection layer, and the electron transport layer contains a fourth organic compound, and the fourth organic compound is a different organic compound from the third organic compound.

[0033] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the metal is any metal in Group 3, Group 11, or Group 13 of the periodic table.

[0034] Further, another aspect of the present invention is a light-emitting device having the above-described structure, in which the first π-deficient heteroaromatic ring contains a phenanthroline ring.

[0035] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the first π-deficient heteroaromatic ring is a 1,10-phenanthroline ring and has an electron-donating group at at least one of the 4-position and the 7-position thereof.

[0036] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the electron-donating group is one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

[0037] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the acidity coefficient pK a of the first organic compound is 8 or more.

[0038] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein when the threshold value of the electron density distribution in atomic units is 0.0004 e / a0 3 the minimum value of the electrostatic potential of the first organic compound is -0.085 E h or less.

[0039] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the spin density of the electron injection layer measured by an electron spin resonance method (ESR: Electron spin resonance) is 5×10 16 spins / cm 3 or more.

[0040] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the electron injection layer is located between the second electrode and the light-emitting layer. Further, another aspect of the present invention is a light-emitting device having the above-described structure, the light-emitting device further comprising a hole injection layer, wherein the hole injection layer is located between the first electrode and the light-emitting layer, and the hole injection layer contains a fifth organic compound having hole-transporting properties and a first substance having an acceptor property with respect to the fifth organic compound. Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the hole injection layer contains a fifth organic compound having hole-transporting properties and an organic compound containing four or more of at least a halogen group and a cyano group. Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the hole injection layer contains a fifth organic compound having hole-transporting properties and a metal or metal oxide different from the metal or metal oxide contained in the electron injection layer.

[0041] Further, another aspect of the present invention is a light-emitting device having the above-described structure, wherein the spin density of the hole injection layer measured by an electron spin resonance method is 1×10 17 spins / cm 3 or more.

[0042] Further, another aspect of the present invention is a light-emitting device including a plurality of light-emitting elements, wherein the plurality of light-emitting elements are respectively any of the above-described light-emitting elements, and each of the plurality of light-emitting elements includes an organic compound layer between a first electrode and a second electrode, the organic compound layer including a light-emitting layer and an electron injection layer, and the organic compound layers included in each of the plurality of light-emitting elements are independent of each other among the plurality of light-emitting elements.

[0043] Further, another aspect of the present invention is a display module including the above-described light-emitting element and at least one of a connector and an integrated circuit.

[0044] Further, another aspect of the present invention is an electronic device including the above-described light-emitting element and at least one of a housing, a battery, a camera, a speaker, and a microphone.

[0045] According to one aspect of the present invention, a novel light-emitting element can be provided. Further, according to one aspect of the present invention, a light-emitting element having good efficiency can be provided. Further, according to one aspect of the present invention, a light-emitting element having good reliability can be provided. Further, according to one aspect of the present invention, a light-emitting element having good efficiency and reliability can be provided.

[0046] Further, according to one aspect of the present invention, a novel light-emitting element manufactured through a photolithography process can be provided. Further, according to one aspect of the present invention, a light-emitting element manufactured through a photolithography process in which an increase in driving voltage is suppressed can be provided. Further, according to one aspect of the present invention, a light-emitting element manufactured through a photolithography process having low manufacturing cost and in which an increase in driving voltage is suppressed can be provided. Further, according to one aspect of the present invention, a light-emitting element manufactured through a photolithography process having good reliability can be provided. Further, according to one aspect of the present invention, a light-emitting element manufactured through a photolithography process having low manufacturing cost and good reliability can be provided. Further, according to one aspect of the present invention, a light-emitting element manufactured through a photolithography process having low driving voltage and good reliability can be provided. Further, according to one aspect of the present invention, a light-emitting element manufactured through a photolithography process having low manufacturing cost, low driving voltage, and good reliability can be provided.

[0047] Further, according to one aspect of the present invention, a novel light-emitting element applicable to a high-definition display device can be provided. Further, according to one aspect of the present invention, a light-emitting element applicable to a high-definition display device having good efficiency can be provided. Further, according to one aspect of the present invention, a light-emitting element applicable to a high-definition display device having good reliability can be provided. Further, according to one aspect of the present invention, a light-emitting element applicable to a high-definition display device having good luminous efficiency and reliability can be provided.

[0048] 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.

[0049] 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.

[0050] 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 descriptions in the specification, the drawings, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figures 1A to 1C is a diagram showing a light-emitting device; Figure 2A and Figure 2B is a diagram showing a light-emitting device; Figure 3A and Figure 3B are a top view and a cross-sectional view of a light-emitting device; Figures 4A to 4E is a cross-sectional view showing an example of a manufacturing method of a display device; Figure 5A and Figure 5B is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 6A to 6D is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 7A to 7C is a cross-sectional view showing an example of a manufacturing method of a display device; Figures 8A to 8C is a cross-sectional view showing an example of a manufacturing method of a display device; Figure 9A and Figure 9B is a cross-sectional view showing an example of a manufacturing method of a display device; Figure 10A and Figure 10B is a perspective view showing an example of the structure of a display module; Figure 11A and Figure 11B is a cross-sectional view showing an example of the structure of a display device; Figure 12 is a perspective view showing an example of the structure of a display device; Figure 13 is a cross-sectional view showing an example of the structure of a display device; Figure 14is a cross-sectional view showing an example of the structure of a display device; Figures 15A to 15C is a diagram showing an example of the structure of a display device; Figure 16 is a cross-sectional view showing an example of the structure of a display device; Figures 17A to 17C is a diagram showing an example of the structure of a display device; Figures 18A to 18D is a diagram showing an example of an electronic device; Figures 19A to 19F is a diagram showing an example of an electronic device; Figures 20A to 20G is a diagram showing an example of an electronic device; Figures 21A to 21C is the analysis result of the spin density distribution in the ground state of a composite material; Figure 22A and Figure 22B is the analysis result of the electrostatic potential map in the ground state of an organic compound; Figures 23A to 23C is the analysis result of the electrostatic potential map in the ground state of a composite material; Figures 24A to 24G is a diagram showing an example of the layout of sub-pixels; Figure 25 is a diagram showing the luminance-current density characteristics of Light Emitting Device 1 and Comparative Light Emitting Device 1; Figure 26 is a diagram showing the luminance-voltage characteristics of Light Emitting Device 1 and Comparative Light Emitting Device 1; Figure 27 is a diagram showing the current efficiency-current density characteristics of Light Emitting Device 1 and Comparative Light Emitting Device 1; Figure 28 is a diagram showing the current density-voltage characteristics of Light Emitting Device 1 and Comparative Light Emitting Device 1; Figure 29 is a diagram showing the field emission spectra of Light Emitting Device 1 and Comparative Light Emitting Device 1. Detailed Embodiments

[0052] 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 modes 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 following embodiments shown.

[0053] 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. Further, in this specification and the like, a device manufactured without using a metal mask or an FMM is sometimes referred to as a device having an MML (Metal Mask Less) structure.

[0054] Embodiment 1 As one of the methods for forming an organic semiconductor film into a specified shape, vacuum evaporation using a metal mask (mask evaporation) is widely employed. However, recently, with the progress of high density and high definition, due to various reasons typified by problems in positional alignment accuracy and problems in the arrangement interval with the substrate, 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 semiconductor film using a photolithography method. Moreover, since it is easier to achieve large area formation by the photolithography method compared with mask evaporation, research on processing of the organic semiconductor film using the photolithography method is underway.

[0055] On the other hand, it has been known that the organic compound layer and the cathode in an organic EL device are affected by atmospheric components such as water and oxygen, and thus processing is usually performed in an inert atmosphere or an atmosphere close to vacuum.

[0056] In particular, an alkali metal, an alkaline earth metal, or their compounds (hereinafter also referred to as Li compounds etc.) are sometimes used for the electron injection layer of a light emitting device. However, these Li compounds etc. have high reactivity with water or oxygen, and rapidly deteriorate when exposed to the atmosphere, resulting in a significant reduction in electron injectability. Further, in the case where another metal having a small work function is used for the cathode, when exposed to water, oxygen, etc., there is a possibility that the electron injectability decreases and the driving voltage increases significantly.

[0057] However, in the process of performing the above-described processing using the photolithography method, it is necessary to expose the light emitting device in the middle of manufacturing, including the cathode and the electron injection layer, to the atmosphere. Moreover, in the processing of the photolithography process, various chemical solutions are used and there is also a washing process, which are harsh conditions that further promote deterioration.

[0058] Therefore, when processing the cathode and the organic compound layer using the photolithography method, there is a possibility that the electron injectability of the cathode and the electron injection layer is significantly reduced. As a result, the driving voltage of the organic EL device processed using the photolithography method increases significantly and it is difficult to obtain good characteristics.

[0059] Note that, in order to avoid deterioration of this characteristic, there is also the following method: perform processing using photolithography before forming the electron injection layer and the cathode, and then form the electron injection layer and the cathode. However, by performing processing after forming the two electrodes, the increase in the number of processes during the photolithography process can be suppressed to a minimum, so there are great advantages in terms of cost. In addition, the opportunity for the organic compound layer to come into contact with the liquid medicine and the atmosphere can be greatly reduced, and the same performance as a light-emitting device manufactured without exposure to the atmosphere can be achieved.

[0060] Accordingly, one aspect of the present invention provides a light-emitting device including a first electrode, an organic compound layer, and a second electrode from one side of a substrate, the light-emitting device being manufactured by performing a photolithography process after forming the second electrode, and having good characteristics.

[0061] Here, the present inventors have found that: by using, as the electron injection layer, a layer including a metal or a metal oxide, an organic compound (first organic compound) including a first π-deficient heteroaromatic ring having an electron-donating group, and an organic compound (second organic compound) including a second π-deficient heteroaromatic ring, even if a photolithography process that exposes the organic compound layer to the atmosphere is performed, an organic EL device in which a decrease in the electron injection property of the electron injection layer is suppressed can be achieved.

[0062] Furthermore, in one aspect of the present invention, the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound, and preferably, the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by 0.80 eV or more and 0.20 eV or less, more preferably by 0.50 eV or more and 0.20 eV or less, still more preferably by 0.50 eV or more and 0.25 eV or less, still more preferably by 0.50 eV or more and 0.30 eV or less, still more preferably by 0.50 eV or more and 0.35 eV or less, and further preferably by 0.50 eV or more and 0.40 eV or less.

[0063] That is, when the LUMO energy level of the first organic compound is set to "LUMO1 (eV)" and the LUMO energy level of the second organic compound is set to "LUMO2 (eV)", LUMO2 preferably satisfies the following formula (1). LUMO1 - 0.80 ≤ LUMO2 ≤ LUMO1 - 0.20 Formula (1)

[0064] More preferably, LUMO2 satisfies formula (2). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.20 Formula (2)

[0065] More preferably, LUMO2 satisfies formula (3). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.25, Formula (3)

[0066] More preferably, LUMO2 satisfies Formula (4). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.30, Formula (4)

[0067] More preferably, LUMO2 satisfies Formula (5). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.35, Formula (5)

[0068] More preferably, LUMO2 satisfies Formula (6). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.40, Formula (6)

[0069] When LUMO2 is within the above range, in one embodiment of the present invention, a light-emitting device can achieve a light-emitting device in which a decrease in the electron injection property of the electron injection layer is suppressed whether or not it undergoes a photolithography process accompanied by exposure of the organic compound layer to the atmosphere. In addition, a light-emitting device with good reliability can be achieved.

[0070] The metal or metal oxide, the first organic compound, and the second organic compound form a donor energy level (Singly Occupied Molecular Orbital (SOMO) energy level or Highest Occupied Molecular Orbital (HOMO) energy level) through interaction. Thereby, the electron injection barrier from the electron injection layer to the electron transport layer can be reduced, and electrons can be smoothly injected and transported to the electron transport layer without using an existing electron injection layer that deteriorates significantly through an unstable photolithography process accompanied by exposure to the atmosphere. In addition, when LUMO2 is within the above range, they can interact more stably, and an electron injection layer that is not easily deteriorated even after a photolithography process accompanied by exposure to the atmosphere can be formed. Therefore, even after a photolithography process accompanied by exposure of the organic compound layer to the atmosphere, electrons can be smoothly injected and transported to the electron transport layer, and thus a light-emitting device with an inhibited rise in driving voltage and good reliability can be manufactured using the photolithography process.

[0071] Note that the HOMO energy level and LUMO 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.

[0072] In addition, as a structure of an electron injection layer including an organic compound (a first organic compound) containing a first π-deficient heteroaromatic ring having an electron-donating group, an organic compound (a second organic compound) containing a second π-deficient heteroaromatic ring, and a metal or metal oxide, a structure of a mixed layer of a metal or metal oxide, the first organic compound, and the second organic compound is preferably employed. Alternatively, a stacked structure of a layer containing a metal and a layer containing the first organic compound and the second organic compound may also be employed.

[0073] When a stacked structure of a layer containing a metal and a layer containing the first organic compound and the second organic compound is employed as the electron injection layer, the following structure is preferably employed: The layer containing the metal and the layer containing the first organic compound and the second organic compound are stacked such that the layer containing the first organic compound and the second organic compound is on the anode side and in contact with each other, and the layer containing the first organic compound and the second organic compound is in contact with the electron transport layer.

[0074] When the electron injection layer is a mixed layer of a metal or metal oxide, the first organic compound, and the second organic compound, the number of layers can be reduced compared to the stacked structure, so the productivity is high and mass production is easy.

[0075] Note that when an alkali metal or alkaline earth metal such as lithium oxide (Li2O) and their oxides are used for the electron injection layer of an existing structure having an organic EL device, a light-emitting device manufactured by a so-called vacuum continuous process that is not exposed to the atmosphere has good characteristics. However, as described above, when manufactured through a photolithography process accompanied by exposure of the organic compound layer to the atmosphere, even in a light-emitting device in which an alkali metal or alkaline earth metal and their oxides are used for the electron injection layer, the driving voltage increases significantly compared to a light-emitting device manufactured by a vacuum continuous process. As described above, this is because the donor property decreases due to deterioration when the oxides of alkali metals or alkaline earth metals are exposed to the atmosphere.

[0076] That is, in another aspect of the present invention, by using an oxide of an alkali metal or alkaline earth metal such as lithium oxide (Li2O), an organic compound (a first organic compound) containing a first π-deficient heteroaromatic ring having an electron-donating group, and an organic compound (a second organic compound) containing a second π-deficient heteroaromatic ring as the electron injection layer, an organic EL device manufactured through a photolithography process accompanied by exposure to the atmosphere can also obtain an organic EL device in which the decrease in electron injection property of the electron injection layer is suppressed as in an organic EL device manufactured by a vacuum continuous process.

[0077] This is because: by using an alkali metal or alkaline earth metal and their oxides, an organic compound containing a first π-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound containing a second π-deficient heteroaromatic ring (second organic compound) as an electron injection layer, a donor energy level (SOMO energy level or HOMO energy level) is formed due to the interaction. However, due to the large and stable stabilization energy caused by the interaction, its energy level is high. Therefore, even after exposure to the atmosphere, the electron injection barrier from the electron injection layer to the electron transport layer is reduced, and electrons can be smoothly injected and transported to the electron transport layer. Therefore, even when exposed to the atmosphere, a tandem organic EL light-emitting device can be realized in which the decrease in the electron injection property of the electron injection layer is suppressed.

[0078] In addition, by using such an electron injection layer, a stable conductive material represented by a conductive metal oxide can be used as the second electrode. Even for a light-emitting device processed by photolithography after forming the second electrode, a light-emitting device with good characteristics in which the increase in the driving voltage is suppressed can be provided. In addition, by setting the LUMO energy level of the second organic compound within the above range, a light-emitting device with good reliability can also be realized.

[0079] <<Electron injection layer>> As described above, the electron injection layer is provided between the cathode and the light-emitting layer, and it contains a metal or metal oxide, an organic compound containing a first π-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound containing a second π-deficient heteroaromatic ring (second organic compound).

[0080] <Metal or metal oxide> As the metal or metal oxide in the electron injection layer, metals or their oxides containing the following elements can be used: alkali metals such as Li (Group 1 elements); alkaline earth metals such as Mg and Ca (Group 2 elements); Group 3 elements containing lanthanide elements such as Y, Eu, and Yb; Group 11 elements such as Cu, Ag, and Au; earth metals such as Al and In (Group 13 elements); and Group 14 elements such as Sn.

[0081] When an alkali metal, an alkaline earth metal, or their oxides are used in a metal or metal oxide, the donor energy level formed by the interaction with the first organic compound and the second organic compound can be a high energy level, and electrons can be smoothly injected from the cathode and transported to the electron injection layer. Thus, a light-emitting device with a low driving voltage and high-efficiency light emission can be provided, so it is preferred. In addition, transition metals and their oxides are preferably used because they are less reactive with components such as water and oxygen in the atmosphere and are relatively stable. Among the above materials, metals or metal oxides containing elements belonging to the odd groups (Group 1, Group 3, Group 11, or Group 13) of the periodic table are preferably used because they are easily interact with the first organic compound and the second organic compound to form a donor energy level.

[0082] In addition, metals or metal oxides with low melting points and can be deposited by vacuum evaporation are preferably used, whereby a mixed layer or a stacked layer with an organic compound can be easily formed. Specifically, for example, metals or metal oxides of Group 11 elements and Group 13 elements have low melting points and are suitable for vacuum evaporation. In addition, metals or metal oxides of Group 11 elements and Group 13 elements are stable to oxygen and water in the atmosphere, so they are preferred. As the metals or metal oxides that can be deposited by vacuum evaporation, the melting point at normal pressure is preferably 2000 °C or lower, 1500 °C or lower, more preferably 1000 °C or lower, or the sublimation temperature under reduced pressure (vacuum of 1 Pa or lower) is preferably 1500 °C or lower, 1000 °C or lower, more preferably 500 °C or lower.

[0083] As such metals or metal oxides, specifically, for example, lithium, magnesium, calcium, ytterbium, silver, indium, and their oxides can be used. Note that even for metals, they may sometimes be oxidized during processes such as deposition and release of the atmosphere and become metal oxides.

[0084] <The first organic compound> As the first organic compound contained in the electron injection layer, an organic compound having a π-deficient heteroaromatic ring can be used. More preferably, an organic compound containing a π-deficient heteroaromatic ring having an electron-donating group is used as the first organic compound, whereby the electron density of the π-deficient heteroaromatic ring can be increased.

[0085] In addition, as the organic compound having a π-deficient heteroaromatic ring, an organic compound having a heteroaromatic ring containing nitrogen is preferably used. As the heteroaromatic ring containing nitrogen, a pyridine ring is preferably used, and an organic compound having a heteroaromatic ring containing two or more pyridine rings is particularly preferably used. This is because the two nitrogen atoms contained in the organic compound having a heteroaromatic ring containing two or more pyridine rings coordinate to the metal and are easily interact with the metal or metal oxide.

[0086] In an organic compound having a heteroaromatic ring containing two or more pyridine rings, in an organic compound having a bipyridine skeleton, a nitrogen atom is more likely to coordinate with a metal, and thus it is likely to interact with a metal or a metal oxide, and is therefore preferred. Further, the phenanthroline ring is rigid and stable, and is therefore preferred. Among them, in particular, the two nitrogen atoms contained in an organic compound having a 1,10-phenanthroline ring are present at positions where they are likely to coordinate with a metal or a metal oxide, and thus it is likely to interact with a metal or a metal oxide, and is therefore preferred.

[0087] When an electron-donating group is introduced into the 1,10-phenanthroline ring, the electron-donating group is preferably substituted at the 4-position and the 7-position of the 1,10-phenanthroline ring. By introducing an electron-donating group at the 4-position and the 7-position of the 1,10-phenanthroline ring, the electron density of the nitrogen atoms at the 1-position and the 10-position can be increased, which is advantageous for the interaction with a metal or a metal oxide.

[0088] Examples of the electron-donating group in the π-deficient heteroaromatic ring include an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, a heterocyclic amino group, and the like. However, the electron-donating group preferably introduced into the π-deficient heteroaromatic ring is not limited thereto. As long as a group capable of increasing the electron density of the π-deficient heteroaromatic ring is introduced into the π-deficient heteroaromatic ring, it can be used as the electron-donating group. Further, the electron-donating group may be introduced into the π-deficient heteroaromatic ring through an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0089] Specific examples of the alkyl group that can be used as the above electron-donating 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, and a 2,3-dimethylbutyl group.

[0090] Specific examples of the alkoxy group that can be used as the above electron-donating 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.

[0091] Specific examples of the aryloxy group that can be used as the above electron-donating 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, and the like. The aryloxy group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0092] Specific examples of the alkylamino group that can be used as the above-described electron-donating group include, for example, dimethylamino, diethylamino, and the like.

[0093] Specific examples of the arylamino group that can be used as the above-described electron-donating group include diphenylamino, bis(α-naphthyl)amino, bis(m-tolyl)amino, and the like. The arylamino group may also have a substituent. Specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0094] Specific examples of the heterocyclic amino group that can be used as the above-described electron-donating 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. Specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0095] [Chemical formula 1]

[0096] In addition, the groups represented by the structural formulas (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17), or (R-21) are more preferable as the electron-donating group. Among them, the groups represented by the structural formulas (R-3), (R-4), (R-8), or (R-21) have a high electron-donating property and can further increase the electron density of the phenanthroline ring, so they are particularly preferable.

[0097] In addition, specific examples of the electron-donating group also include groups represented by the following structural formulas (R-27) and (R-28).

[0098] [Chemical formula 2]

[0099] Note that the organic compound having a π-deficient heterocyclic ring that can be used as the first organic compound may also have both the above-described electron-donating group and other substituents. Specific examples of the substituents other than the above-described electron-donating group that can be introduced into the π-deficient heterocyclic ring also include an aryl group. Specific examples of the aryl group include a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a mesityl group, an o-biphenyl group, an m-biphenyl group, a p-biphenyl group, a 1-naphthyl group, a 2-naphthyl group, a 2-fluorenyl group, and the like. The aryl group may also have a substituent. Specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0100] Structural formulas (100) to (111) show specific examples of organic compounds having a π - electron - deficient heteroaromatic ring that can be used as the first organic compound. Note that the organic compounds that can be used as the first organic compound are not limited to these.

[0101] [Chemical formula 3]

[0102] In addition, when the negative 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 stabilization energy caused by the interaction with a metal or a metal oxide is large and stable, so it is preferred.

[0103] In an organic compound having a π - electron - deficient heteroaromatic ring, the electrostatic potential around the heteroatom of the π - electron - deficient heteroaromatic ring tends to become negative. By introducing an electron - donating group to the π - electron - deficient heteroaromatic ring, the electrostatic potential around the heteroatom of the π - electron - deficient heteroaromatic ring can be further reduced (the absolute value of the negative value is increased).

[0104] The electrostatic potential refers to the interaction energy between a positive point charge with a unit electric charge and the electron distribution of a molecule. In addition, the value of the electrostatic potential also varies according to the threshold of the electron density.

[0105] To improve the efficiency of the interaction with a metal or a metal oxide, the minimum value of the electrostatic potential of the first organic compound is preferably less than (greater in the negative direction than) the minimum value of the electrostatic potential of a π - electron - deficient heteroaromatic ring without substituents.

[0106] Specifically, when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 (e represents the elementary charge (1e = 1.60218×10 -19 C), a0 represents the Bohr radius (1a0 = 5.29177×10 -11 m)), the minimum value of the electrostatic potential of the first organic compound is preferably - 0.085E h (E h represents the 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 in atomic units (also called the density threshold) is 0.003e / a0 3 the minimum value of the electrostatic potential of the first organic compound is preferably - 0.12E h or less, more preferably - 0.13E h or less. In addition, when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3When, the minimum value of the ESP of the first organic compound is preferably -0.085E h Hereinafter, more preferably, when the threshold value of the electron density distribution in atomic units is 0.003e / a0 3 the minimum value is -0.12E h or less.

[0107] The minimum values of the electrostatic potential (ESP) of the organic compounds shown by the above structural formulas (100) to (107) that can be used as the first organic compound, BPhen, mPPhen2P, NBPhen, Phen, and Hid2Phen are estimated by quantum chemical calculations. The structural formulas of the organic compounds represented by the structural formulas (100) to (107), BPhen, mPPhen2P, NBPhen, Phen, and Hid2Phen are shown below.

[0108] [Chemical formula 4]

[0109] As the quantum chemical calculation program, Gaussian09 is used. The calculation is performed using SGI8600 manufactured by HPE. The most stable structure of the first organic compound in the ground state 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.

[0110] Table 1 shows the analysis results of the electrostatic potential of the first organic compound in the ground state. Note that 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 value of the electron density. Table 1 shows the electrostatic potential in the electron density distribution in atomic units when the electron density threshold in atomic units is 0.0004e / a0 3 or 0.003e / a0 3 at that time.

[0111] [Table 1] 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 -0.110 Hid2Phen -0.094 -0.13

[0112] As can be seen from the above table, when the threshold value of the electron density distribution in atomic units is 0.0004e / a0 3 the minimum values of the ESP of the organic compounds represented by the structural formulas (100) to (103) and Hid2Phen are -0.085E h or less and are more suitable for use as the first organic compound. In addition, when the threshold value of the electron density distribution in atomic units is 0.003e / a0 3When the minimum value of the ESP of the organic compounds represented by Structural Formulas (100) to (103) and Hid2Phen is -0.12E h as follows, it is more suitable as the first organic compound.

[0113] This is because: for the organic compounds represented by Structural Formulas (100) to (103) and Hid2Phen, electron-donating groups are introduced at the 4th and 7th positions of the 1,10-phenanthroline ring, thereby having a high electron-donating property to the nitrogen atoms at the 1st and 10th positions of the phenanthroline ring.

[0114] In addition, when the threshold value of the electron density distribution in the atomic unit system is 0.0004 e / a0 3 When the minimum value of the ESP of the organic compounds represented by Structural Formulas (100) and (103) and Hid2Phen is -0.090E h as follows, it is particularly suitable as the first organic compound. In addition, when the threshold value of the electron density distribution in the atomic unit system is 0.003 e / a0 3 When the minimum value of the ESP of the organic compound represented by Structural Formula (103) and Hid2Phen is -0.13E h as follows, it is particularly suitable as the first organic compound.

[0115] In addition, when the threshold value of the electron density distribution in the atomic unit system is 0.0004 e / a0 3 When the minimum value of the ESP of the organic compound represented by Structural Formula (103) and Hid2Phen is -0.090E h as follows and when the threshold value of the electron density distribution in the atomic unit system is 0.003 e / a0 3 When the minimum value of the ESP is -0.13E h as follows, it is further suitable as the first organic compound.

[0116] In addition, when the basicity of the first organic compound is high, through the interaction with holes, the hole transportability in the electron injection layer can be greatly reduced, thereby enabling a light-emitting device with high efficiency and low driving voltage, so it is preferred. Specifically, the acidity coefficient pK of the first organic compound a is preferably 8 or more, more preferably 10 or more, and further preferably 12 or more.

[0117] In addition, when the acidity coefficient pK of the organic compound is unknown a by investigating the acidity coefficient pK of each skeleton of the organic compound a the maximum acidity coefficient pK among them a can be regarded as the acidity coefficient pK of the organic compound a .

[0118] In addition, the acidity coefficient can also be calculated. For example, the acidity coefficient pK can be calculated using the following method. a .

[0119] 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.

[0120] 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.

[0121] In the pK a calculation, one or more atoms in each molecule are specified 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*, then perform a single-point calculation with cc-pVTZ(+), and calculate the pK a value using the empirical correction for functional groups. In the molecule where one or more atoms are specified as basic positions, the largest value in the obtained results is used as the pK a value. The obtained pK a value is shown.

[0122] The acidity coefficient pK a of 2,9hpp2Phen is 13.35, the acidity coefficient pK a of 4,7hpp2Phen is 13.42, the acidity coefficient pK a of Pyrrd-Phen is 11.23, the acidity coefficient pK a of mPPhen2P is 5.16, the acidity coefficient pK a of NBPhen is 5.59, and the acidity coefficient pK a of BPhen is 5.62.

[0123] <Second Organic Compound> The electron injection layer contains, in addition to a metal or a metal oxide and a first organic compound, a second organic compound having a π-deficient heteroaromatic ring. By including the second organic compound, an improvement in heat resistance and an improvement in electron transportability can be achieved, etc. In one embodiment of the present invention, when the π-deficient heteroaromatic ring of the first organic compound is a first π-deficient heteroaromatic ring and the π-deficient heteroaromatic ring of the second organic compound is a second π-deficient heteroaromatic ring, the first π-deficient heteroaromatic ring and the second π-deficient heteroaromatic ring are preferably different rings.

[0124] In addition, as the second π-deficient heteroaromatic ring, a heteroaromatic ring having an oxazole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, a heteroaromatic ring having a triazine skeleton, etc. are preferred, and a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring is particularly preferred, whereby it is electrochemically stable and has high electron transportability.

[0125] Note that the second π-deficient heteroaromatic ring may also have a fused ring structure.

[0126] Furthermore, in one embodiment of the present invention, the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound, and preferably, the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by 0.80 eV or more and 0.20 eV or less, more preferably lower by 0.50 eV or more and 0.20 eV or less, still more preferably lower by 0.50 eV or more and 0.25 eV or less, still more preferably lower by 0.50 eV or more and 0.30 eV or less, still more preferably lower by 0.50 eV or more and 0.35 eV or less, and further preferably lower by 0.50 eV or more and 0.40 eV or less.

[0127] That is, when the LUMO energy level of the first organic compound is set to "LUMO1 (eV)" and the LUMO energy level of the second organic compound is set to "LUMO2 (eV)", LUMO2 preferably satisfies the following formula (1). LUMO1 - 0.80 ≤ LUMO2 ≤ LUMO1 - 0.20 Formula (1)

[0128] More preferably, LUMO2 satisfies formula (2). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.20 Formula (2)

[0129] More preferably, LUMO2 satisfies formula (3). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.25 Formula (3)

[0130] More preferably, LUMO2 satisfies formula (4). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.30 Formula (4)

[0131] More preferably, LUMO2 satisfies formula (5). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.35 Formula (5)

[0132] More preferably, LUMO2 satisfies formula (6). LUMO1 - 0.50 ≤ LUMO2 ≤ LUMO1 - 0.40 Formula (6)

[0133] When LUMO2 is within the above range, in one embodiment of the present invention, a light-emitting device can achieve a light-emitting device with a low driving voltage and good characteristics whether or not it undergoes a photolithography process accompanied by exposure of the organic compound layer to the atmosphere. In addition, a light-emitting device with good reliability can be achieved.

[0134] As the second organic compound, an organic compound having electron-transporting properties can be used. As the organic compound having electron-transporting properties, a substance with 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 is preferably used, and a substance with an electron mobility of 1×10 -6 cm 2 / Vs or more is more preferably used. 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.

[0135] Specific examples of organic compounds having electron transport properties include 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenyl)-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-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3- Organic compounds having an azole skeleton, such as 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4′-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3′- quinoxaline (abbreviation: 2mCzPDBq), 2-[4′-(9-phenyl-9H-carbazol-3-yl)-3,1′-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline Benzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[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-(phenanthrene-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), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 11-[3’-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) 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 - phenylindolo[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-(2 - naphthyl)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,Organic compounds having a triazine skeleton such as 5-triazine (abbreviation: mSiTrz).

[0136] In the above materials, the LUMO energy levels of ZADN, mSiTrz, mPn-mDMePyPTzn, 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr, and βNP-SFx(4)Tzn are suitable, so they are preferred as the second organic compound. By using this organic compound, even in a light-emitting device obtained through a process of exposing the organic compound layer to the atmosphere, a light-emitting device with good characteristics of suppressing the rise in driving voltage can be easily obtained.

[0137] 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 in vacuum evaporation and obtaining good material utilization efficiency.

[0138] In addition, the second organic compound is preferably an organic compound with a glass transition temperature Tg of 100 °C or higher. Thereby, the electron injection layer can have high heat resistance and is not easily crystallized. In this way, it is not easily crystallized even when a part of the organic compound layer is processed by photolithography.

[0139] In addition, as the second organic compound, an organic compound with an acidity coefficient pK a less than 4 can be used. Thereby, the solubility of the second organic compound in water can be reduced, and thus the resistance to water and chemical solutions used in the lithography process can be improved.

[0140] Compared with the solubility of an organic compound with an acidity coefficient pK a of 4 or more in water, the solubility of an organic compound with an acidity coefficient pK a less than 4 in water is low. In addition, compared with the case where an organic compound with an acidity coefficient pK a of 4 or more is used as the second organic compound, when an organic compound with an acidity coefficient pK a less than 4 is used as the second organic compound, the water resistance of the electron injection layer can be improved. In addition, defects such as peeling of the electron injection layer from other layers in the manufacturing process can be suppressed. Thereby, defects that cause defects in the light-emitting device can be suppressed.

[0141] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn, etc. can be used for the second organic compound.

[0142] Note that the acid dissociation constant pKa of 4,8mDBtP2Bfpm is a 0.60. The acid dissociation constant pKa of 11mDBtBPPnfpr is a -1.85. In addition, when the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa of each skeleton of the organic compound is investigated a , and the largest acid dissociation constant pKa among them can be regarded as the acid dissociation constant pKa of the organic compound a . a a .

[0143] In addition, for example, an organic compound with a polarization term δp of the solubility parameter δ of 4.0 MPa or less can be used as the second organic compound. For example, compared with the solubility of an organic compound with a polarization term δp of the solubility parameter δ greater than 4.0 MPa 0.5 in water, an organic compound with a polarization term δp of 4.0 MPa or less has low solubility in water. In addition, compared with the case where an organic compound with a polarization term δp greater than 4.0 MPa 0.5 is used as the second organic compound, when an organic compound with a polarization term δp of 4.0 MPa or less is used as the second organic compound, the water resistance of the electron injection layer can be improved. In addition, defects such as peeling of the electron injection layer from other layers during the lithography process can be suppressed. As a result, defects that cause defects in the light-emitting device can be suppressed. 0.5 0.5 0.5

[0144] In Japanese Patent Application Laid-Open No. 2017-173056, the polarization term δp of the solubility parameter δ of water is 16.0 MPa 0.5 .

[0145] The greater the difference between the polarization term δp of the solubility parameter δ of the organic compound and the polarization term δp of water as the solvent, the lower its solubility in water, so it is preferred. Therefore, it is preferred to use an organic compound with a polarization term δp of 4.0 MPa or less in the solubility parameter δ for the second organic compound. 0.5

[0146] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn can be used for the second organic compound.

[0147] Note that the polarizing term δp of the solubility parameter δ of 8BP-4mDBtPBfpm is 3.5 MPa 0.5 , the polarizing term δp of the solubility parameter δ of 4,8mDBtP2Bfpm is 3.4 MPa 0.5 , the polarizing term δp of the solubility parameter δ of 6BP-4Cz2PPm is 3.4 MPa 0.5 , the polarizing term δp of the solubility parameter δ of 2mDBTBPDBq-II is 3.2 MPa 0.5 , the polarizing term δp of the solubility parameter δ of 9mDBtBPNfpr is 3.8 MPa 0.5 , the polarizing term δp of the solubility parameter δ of 11mDBtBPPnfpr is 3.1 MPa 0.5 , the polarizing term δp of the solubility parameter δ of mPCCzPTzn-02 is 3.5 MPa 0.5 , the polarizing term δp of the solubility parameter δ of BP-BPIcz(II)Tzn is 3.2 MPa 0.5 .

[0148] Note that the polarizing term δp of the solubility parameter δ is calculated according to the following calculation method.

[0149] Used as a classical molecular dynamics calculation software Desmond manufactured by Inc. In addition, the OPLS2005 force field is used. The calculation is performed using Apollo6500 manufactured by Hewlett Packard Enterprise (HPE) Company.

[0150] A standard unit with about 32 molecules is used as the calculation model. As the initial structure of the molecular structure in each compound, multiple of the most stable structure (singlet ground state) obtained by first-principles calculation and the structure with energy close to the most stable structure are mixed at the same ratio, and they are randomly arranged in a non-colliding manner for the molecules. Then, the structure is randomly migrated and rotated by Monte Carlo simulated annealing using OPLS2005 as the force field, thereby migrating the molecules. Furthermore, the molecules are migrated towards the center of the standard unit in a way that maximizes their density, and this is used as the initial configuration.

[0151] For the above first-principles calculation, the quantum chemistry calculation software Jaguar is used to calculate the most stable structure in the singlet ground state by 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 calculation, The Maestro GUI manufactured by Inc. performs sampling for conformational analysis using Mixed torsional / Low-mode sampling. The calculations are carried out using an Apollo 6500 manufactured by Hewlett Packard Enterprise (HPE) Company.

[0152] A Brownian motion simulation is performed on the above initial configuration, followed by an NVT ensemble, and then an NPT ensemble calculation is carried out at 1 atm and 300 K with a relaxation time (30 ns) that is sufficiently longer than the time interval (2 fs) for reproducing molecular vibrations, thereby calculating an amorphous solid. The solubility parameter δ of the obtained amorphous solid is defined by the following formula.

[0153] [Formula 1]

[0154] Here, ΔHv represents the heat of vaporization, which is the value obtained by subtracting the total energy of each molecule averaged over the entire molecular dynamics calculation from the energy of the standard unit, Vm represents the molar volume, R represents the gas constant, and T represents the temperature. The solubility parameter δ has the following tendency: the greater the difference between the substance used as the solvent and the substance used as the solute, the lower the solubility.

[0155] In addition, the solubility parameter δ can be divided into a diffusion term δd and a polarization term δp. Van der Waals interaction has an impact on the diffusion term δd, and electrostatic interaction has an impact on the polarization term δp. In particular, the electrostatic interaction generated between the dipole of the solute and the water molecule has a great influence on the solubility of the solute in water. In fact, the solubility of the organic compound that can be used as the second organic compound in water shows a good correlation with the polarization term δp of the solubility parameter δ obtained by calculation.

[0156] 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 transport properties, and for this reason, the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound.

[0157] The LUMO energy level of the second organic compound is preferably -3.0 eV or more and -2.0 eV or less, and more preferably -3.0 eV or more and -2.5 eV or less. In addition, the LUMO energy level of the first organic compound is preferably -3.0 eV or more and -2.0 eV or less, and more preferably -2.7 eV or more and -2.0 eV or less.

[0158] Thus, electrons can be easily supplied from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Additionally, electrons in the second organic compound can be easily transported thereby.

[0159] In addition, the electron injection layer contains a second organic compound in addition to the metal or metal oxide and the first organic compound, whereby efficient interaction between materials can occur. This can be confirmed by measuring the spin density using the spin resonance method.

[0160] For example, the spin density measured by the ESR method of the film containing the metal or metal oxide and the first organic compound is preferably higher than the spin density measured by the ESR method of the film containing the metal or metal oxide and the second organic compound. Additionally, the spin density measured by the ESR method of the film containing the metal or metal oxide, the first organic compound, and the second organic compound is preferably higher than the spin density measured by the ESR method of the film containing any two of the metal or metal oxide, the first organic compound, and the second organic compound. In this case, efficient interaction between materials can be confirmed.

[0161] More specifically, in the film containing the metal or metal oxide and the first organic compound, for example, the spin density attributed to the signal observed around a g value of 2.00 using the electron spin resonance method is preferably 5×10 16 spins / cm 3 or more, and more preferably 1×10 17 spins / cm 3 or more. In this case, efficient interaction between materials can be confirmed in the film containing the metal or metal oxide and the first organic compound. Alternatively, in the film containing the metal or metal oxide, the first organic compound, and the second organic compound, for example, the spin density attributed to the signal observed around a g value of 2.00 using the electron spin resonance method is preferably 5×10 16 spins / cm 3 or more, and more preferably 1×10 17 spins / cm 3 or more. In this case, it can be confirmed that the film containing the metal or metal oxide, the first organic compound, and the second organic compound interacts more efficiently between materials than in the layer containing only two of the above materials. At this time, in the mixed film containing the metal or metal oxide and the second organic compound, for example, the spin density attributed to the signal observed around a g value of 2.00 using the electron spin resonance method is 2×10 16 spins / cm 3Hereinafter, in a mixed film containing a first organic compound and a second organic compound, for example, the spin density due to a signal observed around a g value of 2.00 by electron spin resonance method is 2×10 16 spins / cm 3 Hereinafter.

[0162] In the electron injection layer, the molar ratio of the metal or metal oxide to the first organic compound (or the sum of the first organic compound and the second organic compound) is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and still more preferably 0.5 or more and 2 or less. 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 still more preferably 0.05 or more and 0.1 or less. By including the metal or metal oxide and the first organic compound (or the first organic compound and the second organic compound) in the above ratio, an electron injection layer having 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 to the second organic compound is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and still more preferably 0.5 or more and 2 or less. By mixing the first organic compound and the second organic compound at this ratio, an electron injection layer having good electron transport properties can be provided. In addition, by using an organic compound having good thermal properties with a high Tg as the second organic compound, an organic EL device with high reliability can be provided.

[0163] In addition, the thickness of the electron injection 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 electron injection layer has a laminated structure of a metal layer and a layer containing the first organic compound, the thickness of the metal layer 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, when the electron injection layer has a laminated structure of a metal layer and a layer containing the 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.

[0164] <Estimating the interaction between metal and organic compound using quantum chemical calculation> Here, quantum chemical calculations are used to analyze the spin density and electrostatic potential (ESP) when a metal interacts with a first organic compound containing a π-deficient heteroaromatic ring having an electron-donating group and a second organic compound having a π-deficient heteroaromatic ring. Note that 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) is used as the first organic compound, 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) is used as the second organic compound, and silver (Ag) is used as the metal for the calculations.

[0165] As the quantum chemical calculation program, Gaussian09 is used. The calculations are performed using an SGI8600 manufactured by HPE. The most stable structures in the ground state of the first organic compound monomer and the second organic compound monomer, the composite material of the first organic compound and the metal, the composite material of the second organic compound and the metal, 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 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. 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 electron-electron interactions. In DFT, since the exchange-correlation interaction is approximated using a functional of a single-electron potential (meaning a function of a function) expressed in terms of electron density, the calculation accuracy is high.

[0166] Figures 21A to 21C The analysis results of the spin density distribution in the ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) are shown. The spheres in the figures represent the atoms constituting the compounds, and the cloud-like objects existing around the atoms represent the spin density distribution at a threshold of 0.003e / a0 in atomic units. 3 when the spin density distribution. In 21A to Figure 21C The shading attached to the compound in indicates the localization of the doublet ground state in the compound. Note that since the ground states of the first organic compound (Pyrrd-Phen) and the second organic compound (11mDBtBPPnfpr) are singlet ground states, the spin density distribution cannot be observed.

[0167] When the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag) is in the doublet ground state, the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other. The metal (Ag) coordinates to the nitrogen atoms (the nitrogen atoms (N) at the 1st and 10th positions) with non-bonding electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and becomes stable, thereby forming a composite material. Thus, according to Figure 21A it is known that a partial spin derived from the unpaired electrons of the metal (Ag) is distributed on a part of the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), especially on the nitrogen atoms (the nitrogen atoms (N) at the 1st and 10th positions) with non-bonding electron pairs. However, due to the weak interaction, most of the spin density is distributed on the metal (Ag).

[0168] In addition, when the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in the doublet ground state, the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other. The metal (Ag) coordinates to the nitrogen atom (N) with non-bonding electron pairs in the phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) and becomes stable, thereby forming a composite material. Thus, according to Figure 21B it is known that a partial spin derived from the unpaired electrons of the metal (Ag) is distributed on a part of the phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), especially on the nitrogen atom (N) with non-bonding electron pairs. However, due to the weak interaction, most of the spin density is distributed on the metal (Ag).

[0169] On the other hand, when the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) in one embodiment of the present invention is in the doublet ground state, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other. The metal (Ag) coordinates to the nitrogen atoms (the nitrogen atoms (N) at the 1st and 10th positions) with non-bonding electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) with non-bonding electron pairs in the phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) and becomes stable, thereby forming a composite material. Thus, according to Figure 21CIt can be seen that the spin originating from the unpaired electrons contained in the metal (Ag) is locally distributed on the second organic compound (11mDBtBPPnfpr). In addition, the spin density distribution of the metal (Ag) cannot be observed. From this, it can be known that due to the interaction between the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag), the second organic compound (11mDBtBPPnfpr) is in the radical anion state.

[0170] Next, Figure 22A , Figure 22B , Figures 23A to 23C The analysis results of the electrostatic potential maps in the ground state of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) are shown. The spheres in the figures represent the atoms constituting the compounds, and the cloud-like substances existing around the atoms represent the electrostatic potential in the electron density distribution when the threshold of the electron density distribution in atomic units is 0.0004e / a0 3 The electrostatic potential is the interaction energy between a positive point charge with a unit electric charge and the electron distribution of the molecule. The electrostatic potential map represents the electrostatic potential in the isoelectron density surface with colors. In the electrostatic potential map, the regions with negative and positive electrostatic potentials are represented by red and blue respectively. The atoms in the region with negative electrostatic potential have negative charges, and the atoms in the region with positive electrostatic potential have positive charges. Note that due to Figure 22A and Figure 22B as well as Figures 23A to 23C are grayscale images, so in order to represent the regions with negative and positive electrostatic potentials, the part represented by dark red (i.e., the region with negative electrostatic potential) is surrounded by a thick dashed line, and the part represented by dark blue (i.e., the region with positive electrostatic potential) is surrounded by a thin dotted line.

[0171] As Figure 22A shown, it can be seen that in the singlet ground state of the first organic compound (Pyrrd-Phen), the electrostatic potential of the nitrogen atoms (the nitrogen atoms (N) at the 1st and 10th positions) with non-bonding electron pairs in the 1,10-phenanthroline ring is negative. In addition, the Mulliken partial charge of this N atom is negative in atomic units, specifically -0.29e. From this, it can be known that this N atom has a negative partial charge.

[0172] As Figure 22BAs shown, it can be seen that in the singlet ground state of the second organic compound (11mDBtBPPnfpr), the electrostatic potential of the nitrogen atom (N) with non-bonding electron pairs in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring is negative. In addition, the Mulliken partial charge of this N atom is negative in atomic units, specifically -0.31e. From this, it can be known that this N atom has a negative partial charge.

[0173] When the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag) is in the doublet ground state, the first organic compound (Pyrrd-Phen) and the metal (Ag) interact, and the metal (Ag) coordinates to the nitrogen atoms (the nitrogen atoms (N) at the 1st and 10th positions) with non-bonding electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and becomes stable, thereby forming a composite material. As a result, as Figure 23A shown, it can be seen that the electrostatic potentials of the nitrogen atoms (the nitrogen atoms (N) at the 1st and 10th positions) with non-bonding electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the metal (Ag) are negative. In addition, the Mulliken partial charges of these N atoms are negative in atomic units, specifically -0.37e, and the Mulliken partial charge of the metal (Ag) is negative in atomic units, specifically -0.18e. From this, it can be known that these N atoms and the Ag atom have negative partial charges.

[0174] When the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in the doublet ground state, the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact, and the metal (Ag) coordinates to the nitrogen atom (N) with non-bonding electron pairs in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) and becomes stable, thereby forming a composite material. As a result, as Figure 23B shown, it can be seen that the electrostatic potentials of the nitrogen atom (N) with non-bonding electron pairs in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) are negative. In addition, the Mulliken partial charges of these N atoms are negative in atomic units, specifically -0.38e, and the Mulliken partial charge of the metal (Ag) is negative in atomic units, specifically -0.09e. From this, it can be known that these N atoms and the Ag atom have negative partial charges.

[0175] On the other hand, when the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) in one embodiment of the present invention is in the doublet ground state, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) interact with each other, and the metal (Ag) 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 (N) having non-bonding electron pairs in the phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. As a result, as Figure 23C shown, it can be seen that the positive electrostatic potential is mainly distributed on the metal (Ag) and the first organic compound (Pyrrd-Phen), and the negative electrostatic potential is mainly distributed on the second organic compound (11mDBtBPPnfpr). In addition, it can be seen that the electrostatic potential of the nitrogen atom (N) having non-bonding electron pairs in the phenanthro[9’,10’:4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative, while the electrostatic potential of the metal (Ag) is positive. Furthermore, the Mulliken partial charge of this N atom is negative in atomic units, specifically -0.62e, while the Mulliken partial charge of the metal (Ag) is positive in atomic units, specifically 0.37e. From this, it can be known that the charge of the Ag atom is distributed on this N atom.

[0176] From this, it can be known that the following combination is formed: an electron donor is formed by the interaction between the first organic compound having an electron-donating group and a π-deficient heteroaromatic ring and the metal, and it acts as an electron donor for the second organic compound having a π-deficient heteroaromatic ring. In one embodiment of the present invention, by using the material having this combination for the electron injection layer, an electron injection layer having good electron injection properties 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 realized.

[0177] <Estimating the SOMO energy level or HOMO energy level in the interaction between a metal and an organic compound using quantum chemical calculations> Next, the stabilization energy and the SOMO energy level or HOMO energy level formed at this time when the metal interacts with the first organic compound containing a π-deficient heteroaromatic ring having an electron-donating group and the second organic compound having a π-deficient heteroaromatic ring are estimated using quantum chemical calculations.

[0178] As a quantum chemistry calculation program, Gaussian09 was used. The calculations were performed using an SGI8600 manufactured by HPE. First, the most stable structures of the first organic compound, the second organic compound, and the metal in the ground state were calculated using density functional theory (DFT), as well as the most stable structures of the composite materials of the first organic compound and the metal, the second organic compound and the metal, and the composite material of the first organic compound, the second organic compound, and the metal in the ground state. 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as the exchange-correlation functional. Then, the stabilization energy was calculated by subtracting the sum of the total energies of the organic compound monomer and the metal monomer from the total energy of the composite material of the organic compound and the metal. That is, (stabilization energy) = (total energy of the composite material of the organic compound and the metal) - (total energy of the organic compound monomer) - (total energy of the metal monomer).

[0179] The following table shows the results calculated with 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) as the first organic compound, 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 9-[3'-(dibenzo[b,d]thiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 8-(p-terphenyl-3-yl)-4-[3-(dibenzo[b,d]thiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 2-[3-(2,6-dimethylpyridin-3-yl)-5-(phenanthren-9-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 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) as the second organic compounds, and indium (In) as the metal. Note that the HOMO and SOMO energy levels in the table are values calculated by the calculation and may differ from the actually measured values.

[0180] [Table 2] HOMO energy level (eV) Pyrrd-Phen -5.65 NBPhen -5.74 9mDBtBPNfpr -5.96 8mpTP4mDBtPBfpm -5.94 mPn-mDMePyPTzn -5.96 βNP-SFx(4)Tzn -5.93

[0181] [Table 3] Stability energy (eV) SOMO energy level (eV) NBphen+In -1.5 -3.28 9mDBtBPNfpr+In -0.8 -3.64 8mpTP4mDBtPBfpm+In -0.8 -3.69 mPn-mDMePyPTzn+In -0.6 -3.08 βNP-SFx(4)Tzn+In -0.7 -3.51

[0182] [Table 4] Stability energy (eV) SOMO energy level (eV) Pyrrd-Phen+NBPhen+In -1.3 -3.02 Pyrrd-Phen+9mDBtBPNfpr+In -1.9 -2.78 Pyrrd-Phen+8mpTP4mDBtPBfpm+In -1.9 -2.86 Pyrrd-Phen+mPn-mDMePyPTzn+In -1.9 -2.99 Pyrrd-Phen+βNP-SFx(4)Tzn+In -1.8 -2.86

[0183] As can be seen from the above table, the stabilization energy of the composite materials of the metal (In) and the second organic compounds (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) is negative, which indicates that when the organic compound and the metal are mixed, the situation where they interact is more stable in terms of energy compared to the situation where the organic compound and the metal do not interact. In addition, the SOMO energy levels formed at this time are all higher than the HOMO energy levels of the first organic compound (Pyrrd-Phen) and the second organic compounds (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn).

[0184] In addition, compared with the second organic compounds (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-deficient heteroaromatic ring different from the 1,10-phenanthroline ring and the metal (In), the second organic compound (NBPhen) having the same 1,10-phenanthroline ring as the first organic compound (Pyrrd-Phen) as the π-deficient heteroaromatic ring and the metal (In) have more stabilized stabilization energy, and the formed SOMO energy level is also higher.

[0185] On the other hand, compared with the composite materials of the metal (In) and the second organic compounds (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), the composite materials of the metal (In), the first organic compound (Pyrrd-Phen) and the second organic compounds (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) according to one embodiment of the present invention have more stabilized stabilization energy. In addition, the SOMO energy levels formed at this time are higher than the HOMO energy levels of the first organic compound (Pyrrd-Phen) and the second organic compounds (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) respectively. The higher the SOMO energy level, the better the electron injection property, so it is preferable.

[0186] At this time, compared with the composite material of a second organic compound (NBPhen) having the same 1,10-phenanthroline ring as the first organic compound (Pyrrd-Phen) which is a π-deficient heteroaromatic ring, the first organic compound (Pyrrd-Phen), and a metal (In), the composite material of a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-deficient heteroaromatic ring different from the 1,10-phenanthroline ring contained in the first organic compound (Pyrrd-Phen), the first organic compound (Pyrrd-Phen), and a metal (In) has a more stabilized stabilization energy, and the formed SOMO energy level is also higher.

[0187] Thus, when an organic compound (first organic compound) containing a first π-deficient heteroaromatic ring having an electron-donating group, an organic compound (second organic compound) containing a second π-deficient heteroaromatic ring, and a metal interact to form a composite material, the first π-deficient heteroaromatic ring and the second π-deficient heteroaromatic ring are preferably different rings, whereby the stability and electron injection property are better.

[0188] In addition, as shown in the above table, the stabilization energy of the composite material of the metal, the first organic compound, and the second organic compound is more stabilized, so it is preferable. Furthermore, the SOMO energy level formed at this time is higher than the HOMO energy levels of the first organic compound and the second organic compound respectively. The higher the SOMO energy level, the better the electron injection property, so it is preferable. In addition, since a metal stable in the atmosphere such as silver or indium is used and an alkali metal compound or the like is not used, a high SOMO energy level is also formed, so an electron injection layer having excellent stability and electron injection property can be formed.

[0189] <Second electrode> The second electrode is an electrode paired with the first electrode. The light-emitting device includes a first electrode formed first, a second electrode, and an organic compound layer located between the first electrode and the second electrode. In addition, preferably, the organic compound layer includes a light-emitting layer and an electron injection layer, the electron injection layer is located between the light-emitting layer and the second electrode, and the electron injection layer is in contact with the second electrode.

[0190] The second electrode preferably uses conductive metal oxides such as indium tin oxide (ITO), indium tin silicon oxide (ITSO) containing silicon or silicon oxide, indium zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). In addition, for example, metal materials such as gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), yttrium (Y), zirconium (Zr), tantalum (Ta), silver (Ag), and magnesium (Mg), or alloy materials containing such metal materials can also be used. Alternatively, nitrides of metal materials (e.g., titanium nitride) can be cited. These materials are not easily deteriorated due to the photolithography process, so a light-emitting device with good characteristics can be obtained even after the photolithography process.

[0191] By making the second electrode light-transmissive, a top-emission type light-emitting device that emits light from the second electrode side can be realized. In the case where the light-emitting device is a bottom-emission type, the second electrode is preferably an electrode with a high visible light reflectivity (40% to 100%, preferably 70% to 100%).

[0192] In addition, some of these materials are not easily used as cathodes due to their high work functions. However, in one embodiment of the present invention, by using the second electrode and the electron injection layer having the above structure, a light-emitting device with good characteristics can be provided.

[0193] Thus, an organic EL device according to one embodiment of the present invention uses a layer including a metal or a 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) containing a second π-deficient heteroaromatic ring as an electron injection layer, and includes a second electrode having the above structure in contact with the electron injection layer. Therefore, even after a process of exposing the organic compound layer to the atmosphere after forming the second electrode, an organic EL device with good characteristics can be realized. Specifically, an electron injection layer that is resistant to oxygen and water in the atmosphere and water and chemical solutions used in the lithography process can be formed. Thus, one embodiment of the present invention can provide a light-emitting device with high moisture resistance, high water resistance, high oxygen resistance, high chemical resistance, low driving voltage, and high luminous efficiency.

[0194] That is, by using the structure according to one embodiment of the present invention, an organic EL light-emitting device with good characteristics manufactured by photolithography including a process of exposing the organic compound layer to the atmosphere can be realized. Thus, a display device with ultra-high definition and good characteristics can be provided.

[0195] In addition, although the light-emitting device of one embodiment of the present invention is particularly preferably used as a light-emitting device through a photolithography process, even if it is used as a light-emitting device manufactured without a photolithography process, it has high stability in the atmosphere, so the yield is improved, and the atmosphere management in the manufacturing process does not need to be too strict, thus contributing to cost reduction.

[0196] Embodiment 2 In this embodiment, a light-emitting device of one embodiment of the present invention will be described in detail.

[0197] Figures 1A to 1C is a schematic diagram of a light-emitting device of one embodiment of the present invention. In the light-emitting device, a first electrode 101 is provided on an insulator 1000, 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.

[0198] 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, and an electron transport layer 114 in addition to the light-emitting layer 113 and the electron injection layer 115. In addition, the organic compound layer 103 may include functional layers such as a hole blocking layer, an exciton blocking layer, and an intermediate layer in addition to the above functional layers. Conversely, any of the above layers may not be provided.

[0199] In addition, the electron injection layer 115 is a layer including a metal or a 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) containing 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).

[0200] The specific structure of the electron injection layer 115 has been described in detail in Embodiment 1, so repeated description is omitted here.

[0201] In addition, the first electrode 101 and the second electrode 102 may be formed into a single-layer structure or a stacked structure. When the electrode has a stacked structure, materials can be selected according to required characteristics such as resistance value, processability, reflectivity, light transmittance, and stability.

[0202] In addition, since the light-emitting device of one embodiment of the present invention is processed by photolithography after the second electrode 102 is formed, as Figures 1A to 1CAs shown, it is also one of the features that the end of the cross-section of the second electrode 102 coincides with the end of the cross-section of the organic compound layer 103 in a direction substantially perpendicular to the surface of the insulating layer 1000. The end of the second electrode 102 and the end of the organic compound layer 103 can be located inside the end of the first electrode 101 as in Figure 1A and Figure 1B , or can be located outside the first electrode 101 as in Figure 1C .

[0203] The first electrode 101 is preferably formed of a metal, alloy, conductive compound, and a mixture thereof having a large work function (specifically, 4.0 eV or more). Specifically, for example, indium tin oxide (ITO: Indium Tin Oxide), indium tin silicon oxide (ITSO: Indium Tin Silicon Oxide) containing silicon or silicon oxide, 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, etc. can also be applied. 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), etc. can be cited. In addition, a layer obtained by laminating them can also be used as the anode. For example, a film obtained by sequentially laminating Al, Ti, and ITSO on Ti has high efficiency due to good reflectivity and can achieve a high resolution of several thousand ppi, and is therefore 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.

[0204] The hole injection layer 111 is in contact with the anode and has the function of facilitating the injection of holes 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) / (polystyrenesulfonic acid) (abbreviation: PEDOT / PSS) can be used to form the hole injection layer 111.

[0205] In addition, the hole injection layer 111 can also be composed of a substance with an electron-accepting property. As the substance with an electron-accepting property, an organic compound having an electron-withdrawing group (halogen group, cyano group) can be used. Examples 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, etc. In particular, compounds such as HAT-CN in which an electron-withdrawing group is bonded to a fused aromatic ring having multiple heteroatoms are thermally stable, so they 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, so they are particularly preferred. Specifically, examples include: α,α',α''-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriyl tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriyl tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], etc. As the substance with 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.

[0206] In addition, the hole injection layer 111 is preferably formed using a composite material containing the above-mentioned material with an electron-accepting property and an organic compound with a hole-transporting property.

[0207] As the organic compound having hole transport properties for a composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. As the organic compound having hole transport properties for a composite material, it is preferable to use an organic compound having a hole mobility of 1×10 -6 cm 2 / Vs or more. The organic compound having hole transport properties for a 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 preferable. Further, 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 preferable, 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 preferable.

[0208] In addition, the composite material containing the above-mentioned electron acceptor material and the organic compound having hole transport properties effectively causes an interaction between the materials. Therefore, as the spin density measured by the electron spin resonance method of the film containing this composite material, it is preferable that the spin density due to the signal observed around the g value of 2.00 is 1×10 17 spins / cm 3 or more.

[0209] Such an organic compound having hole transport properties preferably has any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, it can 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 transport properties are substances including N,N-bis(4-biphenyl)amino, a light-emitting device having a long lifetime can be manufactured, so they are preferable.

[0210] 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'-bis(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-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.

[0211] 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.

[0212] 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.

[0213] In addition, organic compounds having acceptor properties among substances with electron-accepting properties can be easily deposited by evaporation, so they are materials that are easy to use.

[0214] 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.

[0215] Examples of the above hole-transporting materials include compounds having an aromatic amine backbone such as 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-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]fluoren-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.;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-3,3'-bi-9H-carbazole (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, a material having hole transport properties and cited as a composite material for the hole injection layer 111 can also be appropriately used.;

[0216] 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 113 may also contain other materials. In addition, it may be a laminate of two layers with different compositions.

[0217] 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.

[0218] 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.

[0219] 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), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, fused aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, 1,6BnfAPrn-03, etc. have high hole trapping properties, high luminous efficiency and high reliability, so they are preferred.,

[0220] In addition, 5,9-diphenyl-5,9-diaza-13b-borataanthra[3,2,1-de]anthracene (abbreviation: DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborole[2,3,4-kl]phenazaborine-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-bis(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborole[2,3,4-kl]phenazaborine-7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetrakis(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborole[2,3,4-kl]phenazaborine-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-bis(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborole[2,3,4-kl]phenazaborine (abbreviation: Me-tBu4DABNA), N 7 ,N 7 ,N 13 ,N 13 ,5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborole[2,3,4-kl][1,4]benzazaborole[4',3',2':4,5][1,4]benzazaborole[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. In particular, compounds having a diaza-borataanthracene skeleton have a narrow emission spectrum and can obtain blue light emission with good color purity, so they can be used appropriately.,

[0221] 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]phenazaborole (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]phenazaborole (abbreviation: BBCz-Y), etc. can also be appropriately used.

[0222] When a phosphorescent light-emitting material is used as a light-emitting substance in the light-emitting layer, examples of the materials that can be used are as follows.

[0223] 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 having 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 having 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 having 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 having 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)), etc., which are organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands. 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.

[0224] 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-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: Ir(mpmppm)2(acac)), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), etc., which are 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)]), etc., which are 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-pyridyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3-methyl-(2-pyridyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), [2-(4-d3-methyl-5-phenyl-2-pyridyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC]bis[2-(2-pyridyl-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 showing 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 of their particularly excellent reliability or luminescence efficiency.

[0225] In addition, examples include: bis[4,6-bis(3-methylphenyl)pyrimidinato](diisobutyrylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dineopentanoylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-bis(naphthalen-1-yl)pyrimidinato](dineopentanoylmethanato)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)(dineopentanoylmethanato)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.

[0226] In addition, in addition to the above phosphorescent compounds, known phosphorescent compounds can also be selected and used.

[0227] As the TADF material, 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 the metal-containing porphyrin, 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 formula can also be cited.

[0228] [Chemical formula 5]

[0229] 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-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, can also be used. The heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, and has high electron transportability and hole transportability, so it is preferred. Among them, in the skeleton having a π-electron-deficient heteroaromatic 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 acceptor properties and good reliability, so they are preferred. In addition, in the skeleton having a π-electron-rich heteroaromatic 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 indolecarbazole 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-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded, the electron donating property of the π-electron-rich heteroaromatic ring and the electron accepting property of the π-electron-deficient heteroaromatic 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 efficiently obtained, 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-electron-deficient heteroaromatic ring. In addition, as the π-electron-rich skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. can be used.In addition, as the π-deficient electron skeleton, an oxygen-containing 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.

[0230] [Chemical formula 6]

[0231] The TADF material refers to a material in which the energy difference between the S1 energy level and the T1 energy level is small and which has the function of converting triplet excitation energy into singlet excitation energy through reverse intersystem crossing. Therefore, the 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, the triplet excitation energy can be converted into light emission.

[0232] 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.

[0233] 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 the TADF material, 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 energy difference between the S1 energy level and the T1 energy level is 0.3 eV or less, more preferably 0.2 eV or less.

[0234] In addition, when using the TADF material 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.

[0235] As the host material of the light-emitting layer, various carrier transport materials such as a material having electron-transporting properties and / or a material having hole-transporting properties, and the above-mentioned TADF material can be used.

[0236] As a material having hole-transporting properties, an organic compound having an amine skeleton, a π-electron-rich heteroaromatic ring, 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.

[0237] 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 can 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.

[0238] As such organic compounds, for example, there 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]fluoren-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 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), etc., 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), etc., 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), etc., compounds having a furan skeleton. Among them, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton have good reliability and high hole transportability 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.

[0239] As materials having electron-transporting properties, for example, it is preferable to use: beryllium(II) bis(10-hydroxybenzo[h]quinoline) (abbreviation: BeBq2), aluminum(III) bis(2-methyl-8-hydroxyquinolinato)(4-phenylphenolate) (abbreviation: BAlq), zinc(II) bis(8-hydroxyquinolinato) (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 containing π-deficient heteroaromatics, for example, organic compounds containing heteroaromatic rings having an oxazole skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, organic compounds containing heteroaromatic rings having a diazine skeleton, and organic compounds containing heteroaromatic rings having a triazine skeleton can be cited.

[0240] Among them, organic compounds containing heteroaromatic rings having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing heteroaromatic rings having a pyridine skeleton, or organic compounds containing heteroaromatic rings having a triazine skeleton have good reliability, and thus are preferable. 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-transporting properties, which helps to reduce the driving voltage. In addition, benzofuranopyrimidine skeletons, benzothiophenopyrimidine skeletons, benzofuranopyrazine skeletons, and benzothiophenopyrazine skeletons have high electron-accepting properties and high reliability, and thus are preferable.

[0241] Examples of organic compounds having a π-electron-deficient heteroaromatic ring 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-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3 -(dibenzothiophen-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-carbazol-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(9 organic compounds containing a heteroaromatic ring having a pyridine skeleton, such as 2-[3-(2-triphenyl)phenyl]-1,10-phenanthroline (abbreviated as mPPhen2P), 2-[3-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as mTpPPhen), 2-phenyl-9-(2-triphenylene)-1,10-phenanthroline (abbreviated as Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthyl]-1,10-phenanthroline (abbreviated as PnNPhen), and 2-[4-(2-triphenylene)phenyl]-1,10-phenanthroline (abbreviated as pTpPPhen); 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTPDBq -II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mCzBPDBq), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as: 2mPCCzPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mpPCBPDBq), 2-[4-(3,6-Diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(Dibenzo[b]thiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(Dibenzo[b]thiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(Dibenzo[b]thiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(Dibenzo[b]thiophen-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-(dibenzo[b]thiophen-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-(dibenzo[b]thiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-Bis[3-(dibenzo[b]thiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-Bis[3-(dibenzo[b]thiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(Dibenzo[b]thiophen-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-(dibenzo[b]thiophen-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 a heteroaromatic ring having a triazine skeleton. In addition, an organic compound containing a heteroaromatic ring having a diazine skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, or an organic compound containing a heteroaromatic ring having a triazine skeleton has high reliability, so it is preferred. In particular, an organic compound containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and an organic compound containing a heteroaromatic ring having a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage.,

[0242] As the TADF material that can be used as the host material, the same materials as those listed above as the TADF materials can be used. When the 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, whereby the luminous efficiency of the light-emitting device can be improved. At this time, the TADF material is used as the energy donor and the luminescent material is used as the energy acceptor.

[0243] This is very effective when the above 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.

[0244] In addition, it is preferable to use a TADF material that emits light with a wavelength overlapping 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 high-efficiency light emission can be obtained, so it is preferred.

[0245] 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 emitter (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 cited. 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 emitter of the TADF material and the fluorescent emitter away from each other. Here, the emitter refers to the atomic group (skeleton) that causes luminescence in the fluorescent emitter. The emitter preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring. As the above-mentioned emitter, 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, a 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, a 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.

[0246] When a fluorescent luminescent substance is used as the luminescent substance, as the host material, a material having an anthracene skeleton is preferably used. 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, a substance having a diphenylanthracene skeleton, especially a 9,10-diphenylanthracene skeleton, is chemically stable and thus 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 higher than that when including a carbazole skeleton, 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 higher than that when including a carbazole skeleton. 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-dibenz[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)-biphenyl-4'-yl]-anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-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 and are thus preferred.

[0247] In addition, the host material can 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 content of the material with electron-transporting properties is preferably from 1:19 to 19:1.

[0248] 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.

[0249] 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, the 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.

[0250] Note that at least any one of the materials forming the exciplex can be a phosphorescent light-emitting substance. Thereby, the triplet excitation energy can be efficiently converted into singlet excitation energy through reverse intersystem crossing.

[0251] Regarding the combination of materials for efficiently forming an exciplex, the HOMO energy level of the material with hole-transporting properties is preferably higher than the HOMO energy level of the material with electron-transporting properties. In addition, the LUMO energy level of the material with hole-transporting properties is preferably higher than the LUMO energy level of the material with electron-transporting properties. Note that the LUMO energy level and HOMO energy level of the material can be obtained from the electrochemical characteristics (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0252] Note that the formation of an exciplex can be confirmed, for example, by comparing the emission spectra of a material having hole-transporting properties, the emission spectra of a material having electron-transporting properties, and the emission spectra of a mixed film formed by mixing these materials. When a phenomenon in which 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 material having hole-transporting properties, the transient PL of a material having electron-transporting properties, 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 material having hole-transporting properties, the transient EL of a material having electron-transporting properties, 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.

[0253] The electron transport layer 114 is a layer containing a material having electron-transporting properties. As the material having electron-transporting properties, a material having an electron mobility of 1×10 -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 / Vs or more when the square root of the electric field strength [V / cm] is 600 is preferably used. In addition, as long as the material has higher electron-transporting properties than hole-transporting properties, materials 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.

[0254] As the organic compound having electron-transporting property that can be used for the above-described electron transport layer 114, the organic compound having electron-transporting property in the above-described light-emitting layer 113 and the organic compounds 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, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton have good reliability, and thus are preferred. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds 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 ring 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 a high HOMO level such as 2mPCCzPDBq and DACT-II, whereby a light-emitting device with a low driving voltage can be obtained.

[0255] In addition, the electron transport layer preferably contains an organic compound having an acid dissociation constant pK a less than 4 and having electron-transporting property.

[0256] 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 level is 0.5 eV or more lower than the HOMO level of the material contained in the light-emitting layer.

[0257] 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.

[0258] The second electrode 102 is preferably formed in contact with the electron injection layer 115. The structure of the second electrode 102 has been described in detail in Embodiment 1, and thus repeated description is omitted.

[0259] 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, and 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.

[0260] The conductive material forming the second electrode 102 can be deposited by dry methods such as vacuum evaporation and sputtering, inkjet printing, spin coating, etc. In addition, it can also be formed by wet methods such as the sol-gel method or a wet method using a paste of a metal material.

[0261] In addition, when it is a top-emission type light-emitting device, by depositing an organic compound on the second electrode to form a cover layer, the light extraction efficiency can be improved. The cover layer can be a single-layer structure or a laminated structure. When it is a laminated structure, the light extraction efficiency can be further improved by using organic compounds with different refractive indices respectively.

[0262] In addition, as a method for forming the organic compound layer 103, various methods can be used regardless of whether it is a dry method or a wet method. For example, vacuum evaporation, gravure printing, offset printing, screen printing, inkjet printing, spin coating, etc. can also be used.

[0263] In addition, the above-described electrodes or layers can also be formed by using different deposition methods.

[0264] In the case of a deposition method that causes great damage to the substrate, such as sputtering, when forming the second electrode 102, Figure 1B as shown, a P-type layer 117 can also be provided to protect the electron injection layer 115. The P-type layer 117 can be formed using the composite materials described above as the materials that can be used for the hole injection layer 111. Since transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide are stronger than organic compounds, by using them as the acceptor-type substances for the P-type layer, damage during the formation of the second electrode 102 can be prevented, so they are preferred.

[0265] Note that, although not shown in the figure, an electron relay layer may also be provided between the electron injection layer 115 and the P-type layer 117. The electron relay layer contains at least a substance with electron transport properties, can prevent the interaction between the electron injection layer 115 and the P-type layer 117, and can transfer electrons smoothly. It is preferable to set the LUMO energy level of the substance with electron transport properties contained in the electron relay layer 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 electron injection layer 115. The specific value of the LUMO energy level of the substance with electron transport properties in the electron relay layer is preferably -5.0 eV or higher, more 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, phthalocyanine materials or metal complexes having metal-oxygen bonds and aromatic ligands are preferably used. Specifically, as the substance with electron transport properties that can be used in the electron relay layer, diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), 3,4,9,10-perylene tetracarboxylic diimide (abbreviation: PTCDI), 3,4,9,10-perylene tetracarboxylic acid-bis-benzimidazole (abbreviation: PTCBI) and other perylene tetracarboxylic acid derivatives, (C 60 -I h [[ID=I4]])[5,6]fullerene (abbreviation: C 60 )、(C 70 -D 5h )[5,6]fullerene (abbreviation: C 70 ) can be used. In addition, compounds having a hetero-fen skeleton with a ring-fen skeleton including a heterocycle can be used, and as such a compound, phthalocyanine compounds such as phthalocyanine (abbreviation: H2Pc) can be used. In addition, copper phthalocyanine (abbreviation: CuPc), zinc phthalocyanine (abbreviation: ZnPc), cobalt phthalocyanine (abbreviation: CoPc), iron phthalocyanine (abbreviation: FePc), tin phthalocyanine (abbreviation: SnPc), tin oxide phthalocyanine (abbreviation: SnOPc), titanium oxide phthalocyanine (abbreviation: TiOPc), vanadium oxide phthalocyanine (abbreviation: VOPc) and other metal phthalocyanines and their derivatives containing copper, zinc, cobalt, iron, chromium, nickel, etc. can also be used. In addition, phthalocyanine metal complexes such as copper phthalocyanine or zinc phthalocyanine or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine are particularly preferably used.

[0266] In addition, the thickness of the electron relay layer is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less.

[0267] Next, refer to Figure 1BA method of describing a light-emitting device having a structure in which a plurality of light-emitting units are stacked (also referred to as a stacked device or a series device). The 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 a structure substantially the same as that of the organic compound layer 103 shown in Figure 1A That is to say, it can be said that Figure 1B The light-emitting device shown in is a light-emitting device having a plurality of light-emitting units, while Figure 1A The light-emitting device shown in is a light-emitting device having one light-emitting unit.

[0268] In Figure 1C , 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, and the same materials as those described in Figure 1A can be applied.

[0269] The intermediate layer 513 has a function of injecting electrons into one light-emitting unit and holes into the other light-emitting unit when a voltage is applied 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 holes into the second light-emitting unit 512.

[0270] 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, which have been described as materials constituting the composite material above. 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.

[0271] 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.

[0272] The electron relay layer 118 has the same structure as the electron relay layer mentioned in the description of Figure 1B , so repeated description is omitted.

[0273] The N-type layer 119 can use 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)).

[0274] 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. Additionally, as the substance with electron transport properties, the same materials as those described above for the electron transport layer 114 can be used.

[0275] Alternatively, a layer described as the layer used as the electron injection layer in Embodiment 1 can be provided at the same position as the N-type layer 119 instead of the N-type layer 119. This layer includes 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) containing a second π-deficient heteroaromatic ring. A tandem light-emitting device with good characteristics can also be manufactured using this structure.

[0276] When the anode side of the light-emitting unit is in surface contact with the intermediate layer 513, the charge generation layer of the intermediate layer 513 can also serve as the hole injection layer of the light-emitting unit, so the light-emitting unit may not be provided with a hole injection layer. When the cathode side of the light-emitting unit is in surface contact with the intermediate layer 513, the intermediate layer 513 can also serve as the electron injection layer of the light-emitting unit, so the light-emitting unit may not be provided with an electron injection layer.

[0277] In addition, the first light-emitting unit 511 and the second light-emitting unit 512 can have a structure that emits the same light color or a structure that emits different light colors. Additionally, the materials of the corresponding layers (hole transport layer, light-emitting layer, electron transport layer, etc.) that make up the first light-emitting unit 511 and the second light-emitting unit 512 can also be the same as each other. Additionally, the material of the hole injection layer of the light-emitting unit on the anode side can be the same as the material of the P-type layer 117 of the intermediate layer, and the material of the electron injection layer of the light-emitting unit on the cathode side can be the same as the material of the N-type layer 119 of the intermediate layer 513.

[0278] Although a light-emitting device having two light-emitting units is described in Figure 1C , 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 disposing a plurality of light-emitting units separated by an 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 performing low-voltage driving and having low power consumption can be realized.

[0279] 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 light-emitting colors of red and green from a first light-emitting unit and a light-emitting color of blue 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.

[0280] In addition, each layer and electrode such as the above-described organic compound layer 103, the first light-emitting unit 511, the second light-emitting unit 512, and the intermediate layer 513 can be formed by methods such as vapor deposition (including vacuum vapor deposition), droplet ejection (also referred to as inkjet), coating, gravure printing, and the like. In addition, it may contain a low-molecular material, a medium-molecular material (including oligomers, dendrimers), or a high-molecular material.

[0281] Figure 2A 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.

[0282] 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 102a opposite to the first electrode 101a, and the organic compound layer 103a includes an electron injection layer 115a. Although a structure in which the organic compound layer 103a includes 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 is shown, the organic compound layer 103a may also have a stacked structure different from the above structure.

[0283] 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 102b opposite the first electrode 101b. The organic compound layer 103b includes an electron injection layer 115b. Although the organic compound layer 103b is shown as having 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.

[0284] The structures of the electron injection layer 115a and the second electrode 102a in the light-emitting device 130a and the structures of the electron injection layer 115b and the second electrode 102b in the light-emitting device 130b are preferably the structures described in Embodiment 1.

[0285] The organic compound layer 103a and the organic compound layer 103b, and the second electrode 102a and the second electrode 102b are processed by photolithography after the formation of the second electrode 102a and after the formation of the second electrode 102b, respectively, so they are independent of each other. A light-emitting device according to one embodiment of the present invention can obtain a light-emitting device with good characteristics even when processed by photolithography after the formation of the second electrode 102a and after the formation of the second electrode 102b, respectively.

[0286] In addition, the end portion (outline) of the second electrode 102a and the end portion (outline) 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 portion (outline) of the second electrode 102b and the end portion (outline) of the organic compound layer 103b are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate.

[0287] In addition, due to the 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.

[0288] Figure 2B It is a diagram of two adjacent series-connected light-emitting elements (light-emitting devices 130c, 130d) manufactured by photolithography.

[0289] The light-emitting device 130c includes an organic compound layer 103c between a first electrode 101c and a second electrode 102c 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 2BAn example in which two light-emitting units are stacked is shown, but three or more light-emitting units may also be stacked. In addition, in Figure 2B , 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. 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. The presence or absence of the electron relay layer 118c is not considered.

[0290] The light-emitting device 130d includes an organic compound layer 103d between the first electrode 101d and the second electrode 102d on the insulating layer 175. The organic compound layer 103d has a structure in which the first light-emitting unit 501d and the second light-emitting unit 502d are stacked with the intermediate layer 116d therebetween. Note that although Figure 2B An example in which two light-emitting units are stacked is shown, but three or more light-emitting units may also be stacked. In addition, in Figure 2B , the first light-emitting unit 501d includes a hole injection layer 111d, a first hole transport layer 112d_1, a first light-emitting layer 113d_1, and a first electron transport layer 114d_1. The intermediate layer 116d includes a P-type layer 117d, an electron relay layer 118d, and an N-type layer 119d. The 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. The presence or absence of the electron relay layer 118d is not considered.

[0291] In the light-emitting device 130c and the light-emitting device 130d, the electron injection layer 115c and the electron injection layer 115d, and the second electrode 102c and the second electrode 102d preferably have the structures described in Embodiment 1.

[0292] In addition, since the organic compound layer 103c and the organic compound layer 103d, and the second electrode 102c and the second electrode 102d are processed by photolithography after the formation of the second electrode 102c and after the formation of the second electrode 102d, 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 the formation of the second electrode 102c and after the formation of the second electrode 102d, respectively.

[0293] In addition, the end portions (profiles) of the second electrode 102c and the organic compound layer 103c are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate. In addition, the end portions (profiles) of the second electrode 102d and the organic compound layer 103d are processed by photolithography, so they are substantially aligned in the direction perpendicular to the substrate.

[0294] 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 by 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 0.5 μm or more and 5 μm or less.

[0295] In addition, since the second electrode 102a and the second electrode 102b are independent of each other, or the second electrode 102c and the second electrode 102d are independent of each other, it is preferable to form the auxiliary electrode 105 in order to apply a voltage to the plurality of second electrodes included in the light-emitting device. The auxiliary electrode 105 is preferably formed after forming an insulating layer 106 between the second electrode 102a and the second electrode 102b or between the second electrode 102c and the second electrode 102d to prevent short circuits with the organic compound layer or the first electrode. The insulating layer 106 is preferably formed using an organic insulating material. The auxiliary electrode 105 can use a material that can be used for the second electrode.

[0296] The light-emitting device according to one embodiment of the present invention processes the organic compound layer by photolithography and can perform processing with sufficient precision, whereby 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 having 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 can realize a light-emitting device having good characteristics.

[0297] In addition, since the second electrode and the organic compound layer of the light-emitting device according to one embodiment of the present invention are processed at one time by photolithography after forming the second electrode, the profiles of the layers included in the organic compound layer are substantially aligned when viewed from a direction substantially perpendicular to the surface of the insulating layer on which the first electrode is formed. In addition, the end portion of the cross-section of the second electrode and the end portion of the cross-section of the first layer are substantially aligned in the direction substantially perpendicular to the surface of the insulating layer on which the first electrode is formed. Here, "substantially aligned" in this specification means that the difference between the profile A of layer A and the profile B of layer B among the layers A and B in contact with each other is within 5% of the width of the organic compound layer on the line perpendicular to the profile of the portion being compared. In addition, substantially perpendicular means an angle of 85° to 95°.

[0298] The structure of this embodiment can be used in appropriate combination with other structures.

[0299] Embodiment 3 In this embodiment, a mode in which a light-emitting device according to one mode of the present invention is used as a display element of a display device will be described.

[0300] As Figure 3B shown, a plurality of light-emitting devices 130 are formed on an insulating layer 175 and constitute a display device.

[0301] The display device 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.

[0302] In this specification and the like, for example, when describing the common content among the sub-pixels 110R, the sub-pixel 110G, and the sub-pixel 110B, it is sometimes described as the sub-pixel 110. Similarly, when describing the common content among other constituent elements distinguished by letters, it is sometimes described using symbols omitting the letters.

[0303] The sub-pixel 110R emits red light, the sub-pixel 110G emits green light, and the sub-pixel 110B emits blue light. Thus, a full-color image can be displayed on the pixel portion 177. In this embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are taken as an example for description, but a combination of sub-pixels of other colors can also be used. In addition, the number of sub-pixels is not limited to three, and four or more can also be used. As four sub-pixels, for example, sub-pixels of four colors, R, G, B, and white (W); sub-pixels of four colors, R, G, B, and yellow (Y); and sub-pixels of four colors, R, G, B, and infrared light (IR); etc. can be cited.

[0304] 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 the Y direction, for example, perpendicularly.

[0305] In Figure 3A 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.

[0306] In addition, the layout of the sub-pixels is not limited to this, and various methods such as stripe arrangement, S stripe arrangement, matrix arrangement, Delta arrangement, Bayer arrangement, and Pentile arrangement can be adopted, for example. Figures 24A to 24G An example of the layout of the sub-pixels is shown.

[0307] Figure 24AThe pixel 178 shown adopts an S stripe arrangement. Figure 24A The pixel 178 shown is composed of three sub-pixels: a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0308] Figure 24B The pixel 178 shown includes Sub-pixel with a top surface shape of an approximate trapezoid or approximate triangle with rounded corners Sub-pixel 110R , Sub-pixel 110G with a top surface shape of an approximate trapezoid or approximate triangle with rounded corners and a sub-pixel 110B having a top surface shape of an approximate quadrangle or an approximate hexagon with rounded corners. In addition, the light-emitting area of the sub-pixel 110R is larger than that of the sub-pixel 110G. In this way, the shapes and sizes of the respective sub-pixels can be determined independently. For example, the size of a sub-pixel including a highly reliable light-emitting device can be smaller.

[0309] Figure 24C The pixels 124a and 124b shown adopt a Pentile arrangement. In Figure 24C the example shown, pixels 124a including a sub-pixel 110R and a sub-pixel 110G and pixels 124b including a sub-pixel 110G and a sub-pixel 110B are alternately arranged.

[0310] Figures 24D to 24F The pixels 124a and 124b shown adopt a Delta arrangement. The pixel 124a includes two sub-pixels (a sub-pixel 110R and a sub-pixel 110G) in the upper row (the first row) and one sub-pixel (a sub-pixel 110B) in the lower row (the second row). The pixel 124b includes one sub-pixel (a sub-pixel 110B) in the upper row (the first row) and two sub-pixels (a sub-pixel 110R and a sub-pixel 110G) in the lower row (the second row).

[0311] Figure 24D An example where each sub-pixel has a top surface shape of an approximate quadrangle with rounded corners is shown, Figure 24E an example where each sub-pixel has a circular top surface shape is shown, Figure 24F an example where each sub-pixel has a top surface shape of an approximate hexagon with rounded corners is shown.

[0312] In Figure 24F , each sub-pixel is arranged inside a closely arranged hexagonal area. Each sub-pixel is arranged in such a way that when focusing on one sub-pixel, it is surrounded by six sub-pixels. In addition, it is arranged so that sub-pixels emitting light of the same color are not adjacent. For example, each sub-pixel is arranged in such a way that when focusing on the sub-pixel 110R, it is surrounded by three sub-pixels 110G and three sub-pixels 110B that are alternately arranged.

[0313] Figure 24GSpecifically, in a plan view, the top sides of two subpixels arranged in the row direction (for example, subpixel 110R and subpixel 110G or subpixel 110G and subpixel 110B) are offset from each other.

[0314] exist Figures 24A to 24G In the illustrated pixels, for example, sub-pixel 110R is preferably configured as sub-pixel R emitting red light, sub-pixel 110G is preferably configured as sub-pixel G emitting green light, and sub-pixel 110B is preferably configured as sub-pixel B emitting blue light. Note that the sub-pixel structure is not limited to this, and the colors emitted by the sub-pixels and their arrangement order can be appropriately determined. For example, sub-pixel 110G can be configured as sub-pixel R emitting red light, and sub-pixel 110R can be configured as sub-pixel G emitting green light.

[0315] Note that when using Figure 3A and Figure 24G In the case of the so-called stripe configuration shown, the second electrodes 102 of light-emitting devices emitting the same color can be formed continuously. In this case, even if photolithography is performed after the second electrodes 102 are formed, a voltage can be applied to each light-emitting device without the need for the auxiliary electrode 105. If the second electrodes 102 of each light-emitting device are independent of each other after photolithography, it is preferable to form the auxiliary electrode 105.

[0316] A connection portion 140 is provided outside the pixel portion 177, and a region 141 may be provided. The region 141 is provided between the pixel portion 177 and the connection portion 140. The organic compound layer 103 is provided in the region 141. The connection portion 140 is provided with a conductive layer 151C.

[0317] exist Figure 3A In the example shown, the region 141 and the connection portion 140 are located on the right side of the pixel portion 177. However, there is no particular limitation on the positions of the region 141 and the connection portion 140. Alternatively, there may be one or more regions 141 and the connection portion 140.

[0318] Figure 3B It is along Figure 3A An example of a cross-sectional view along the dotted line A1-A2 in FIG. Figure 3B As shown, the display device includes an insulating layer 171, a conductive layer 172 on insulating layer 171, an insulating layer 173 on insulating layer 171 and on conductive layer 172, an insulating layer 174 on insulating layer 173, and an insulating layer 175 on insulating layer 174. Insulating layer 171 is provided on a substrate (not shown). Insulating layer 175, insulating layer 174, and insulating layer 173 are provided with openings that reach conductive layer 172, and plugs 176 are provided so as to fit into these openings.

[0319] In the pixel portion 177, a light-emitting device 130 is provided on the insulating layer 175 and the plug 176. In addition, a protective layer 131 is provided so as to cover the light-emitting device 130. The substrate 120 is bonded to the protective layer 131 by a resin layer 122. Further, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are preferably provided between adjacent light-emitting devices 130.

[0320] Figure 3B A cross section of a plurality of inorganic insulating layers 125 and a plurality of insulating layers 127 is shown, but when the display device is viewed from above, the inorganic insulating layer 125 and the insulating layer 127 are preferably formed as a connected single layer, respectively. In other words, the insulating layer 127 is preferably an insulating layer having an opening on the first electrode.

[0321] In Figure 3B the light-emitting devices 130R, 130G, and 130B are shown as the light-emitting device 130. The light-emitting devices 130R, 130G, and 130B can emit light of different colors from each other. For example, the light-emitting device 130R can emit red light, the light-emitting device 130G can emit green light, and the light-emitting device 130B can emit blue light. In addition, the light-emitting device 130R, 130G, or 130B can also emit other visible light or infrared light.

[0322] 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.

[0323] The light-emitting device 130R has the structure shown in Embodiment 1 and Embodiment 2. The light-emitting device 130R includes a first electrode 101R (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode 101R, and a second electrode 102 on the organic compound layer 103R. The electron injection layer, which is the outermost surface layer of the organic compound layer 103R, and the second electrode 102R have the structures described in Embodiment 1 and Embodiment 2. By having this structure, damage to the light-emitting layer or the active layer in the photolithography process can be suppressed, and a light-emitting device 130R having good film quality and electrical characteristics can be provided.

[0324] The light-emitting device 130G has the structures shown in Embodiment 1 and Embodiment 2. The light-emitting device 130G includes a first electrode 101G (pixel electrode) composed of a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode 101G, and a second electrode 102 on the organic compound layer 103G. The electron injection layer, which is the outermost surface layer of the organic compound layer 103G, and the second electrode 102G have the structures described in Embodiment 1 and Embodiment 2. By having this structure, damage to the light-emitting layer or the active layer during the photolithography process can be suppressed, and a light-emitting device 130G with good film quality and electrical characteristics can be provided.

[0325] The light-emitting device 130B has the structures shown in Embodiment 1 and Embodiment 2. The light-emitting device 130B includes a first electrode 101B (pixel electrode) composed of a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode 101B, and a second electrode 102B on the organic compound layer 103B. The electron injection layer, which is the outermost surface layer of the organic compound layer 103B, and the second electrode 102B have the structures described in Embodiment 1 and Embodiment 2. By having this structure, damage to the light-emitting layer or the active layer during the photolithography process can be suppressed, and a light-emitting device 130B with good film quality and electrical characteristics can be provided.

[0326] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are island-shaped layers that are independent in each light-emitting device or for each emission color. Note that the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are preferably not overlapped with each other. By setting the organic compound layer 103 as an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-definition display device. Thereby, crosstalk can be prevented to realize a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0327] In addition, the second electrode 102R, the second electrode 102G, and the second electrode 102B are independent in an island shape for each light-emitting device or for columns of the same emission color. Note that the second electrode 102R, the second electrode 102G, and the second electrode 102B are preferably not overlapped with each other.

[0328] Preferably, after the insulating layer 127 is formed on the second electrode 102 so as to cover the side surface of the light-emitting device 130, the auxiliary electrode 105 is formed, whereby it is easy to supply voltage to the second electrode 102. The auxiliary electrode 105 can be made of a metal material, for example. 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), and magnesium (Mg), and alloys obtained by appropriately combining them can be used.

[0329] As the auxiliary electrode 105, an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can also be used. For example, a conductive oxide including 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 is preferably used. Note that in the case where the light-emitting device 130 is a top-emission type light-emitting device, a conductive metal oxide having translucency is preferably used as the auxiliary electrode 105.

[0330] The island-shaped organic compound layer 103 is formed by depositing an organic compound film and forming a second electrode, and then processing the organic compound film and the second electrode 102 by photolithography. Since the electron injection layer and the second electrode of the light-emitting device according to one embodiment of the present invention have the structure shown in Embodiment 1, a light-emitting device with good characteristics in which an increase in driving voltage is suppressed can be obtained even when processing is performed by photolithography after the second electrode 102 is formed. In addition, by performing processing by photolithography after the second electrode 102 is formed, a light-emitting device that is inexpensive and has good reliability can be obtained.

[0331] In the display device according to one embodiment of the present invention, the first electrode 101 (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in Figure 3B the example shown, the first electrode 101 of the light-emitting device 130 has a stacked structure including a conductive layer 151 provided on one side of the insulating layer 171 and a conductive layer 152 provided on one side of the organic compound layer.

[0332] As the conductive layer 151, a metal material can be used, for example. 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 be used.

[0333] 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, a conductive oxide including 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 is preferably used. 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.

[0334] 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 also 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 also 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.

[0335] Figure 3B The end of the conductive layer 151 in [description] has a tapered shape. Specifically, the end of the conductive layer 151 preferably has a tapered shape with a taper angle less than 90°. At this time, the conductive layer 152 provided along the side surface of the conductive layer 151 also has a tapered shape. By making the end of the conductive layer 152 have a tapered shape, the coverage of the organic compound layer 103 provided along the side surface of the conductive layer 152 can be improved.

[0336] In addition, the ends of the conductive layer 151 and the conductive layer 152 may not have a tapered shape, that is, they may be substantially perpendicular. In addition, the end of the organic compound layer 103 is preferably located inside the first electrode 101. At this time, the leakage current through the organic compound layer 103 can be reduced, and thus a display device with a low driving voltage and good display performance can be obtained.

[0337] In the display device according to one embodiment of the present invention, the light-emitting device 130 has the structure shown in Embodiment 1 and Embodiment 2, and thus a light-emitting device with good reliability can be realized.

[0338] Next, referring to Figures 4A to 4E to Figure 9A and Figure 9B an example of a manufacturing method of a display device having the structure shown in Figure 3A will be described.

[0339] [Example of Manufacturing Method 1] The thin films (such as insulating films, semiconductor films, and conductive films) 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), atomic layer deposition (ALD: Atomic Layer Deposition), or the like.

[0340] In addition, the thin films (such as insulating films, semiconductor films, and conductive films) constituting the display device can be formed by wet deposition methods such as spin coating, dipping, spraying, inkjet, dispenser method, screen printing, offset printing, doctor knife method, slot die coating, roll coating, curtain coating, or blade coating.

[0341] In addition, when processing the thin films constituting the display device, for example, lithography can be used for processing.

[0342] In lithography, as the light for exposure, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these lights can be used. In addition, ultraviolet light, KrF laser, or ArF laser can also be used. In addition, immersion exposure technology can also be used for exposure. In addition, as the light for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays can also be used. In addition, instead of the light for exposure, an electron beam can also be used.

[0343] In the etching of the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0344] First, as Figure 4A shown, an 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.

[0345] As the substrate, a substrate having at least heat resistance capable of withstanding the subsequent heat treatment can be used. For example, the following can be used: a glass substrate; a quartz substrate; a sapphire substrate; a ceramic substrate; an organic resin substrate; or a semiconductor substrate such as a single-crystal semiconductor substrate or a polycrystalline semiconductor substrate made of silicon, silicon carbide, etc., a compound semiconductor substrate such as silicon germanium, an SOI substrate, etc.

[0346] Next, as Figure 4A shown, openings reaching the conductive layer 172 are formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Next, the plug 176 is formed so as to embed in the opening.

[0347] Next, as Figure 4A 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 and a conductive film 152f that will become the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the conductive layer 152C are formed on the plug 176 and the insulating layer 175. As the conductive film 151f, for example, a metal material can be used. As the conductive film 152f, for example, an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used.

[0348] Next, as Figure 4A shown, a resist mask 191 is formed on the conductive film 152f. The resist mask 191 can be formed by coating a photosensitive material (photoresist) and performing exposure and development.

[0349] Next, as Figure 4B shown, for example, the conductive film 151f and the conductive film 152f in the regions not overlapping with the resist mask 191 are removed. Thereby, the conductive layer 151 and the conductive layer 152 are formed.

[0350] Next, as Figure 4C shown, the resist mask 191 is removed. The resist mask 191 can be removed, for example, by ashing using oxygen plasma.

[0351] Next, as Figure 4D shown, an insulating film 156f that will later become the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, and the insulating layer 156C is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, the conductive layer 152C, and the insulating layer 175.

[0352] The insulating film 156f can use an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitrogen oxide insulating film. For example, a silicon oxynitride film can be used.

[0353] Next, as Figure 4EAs shown, by processing the insulating film 156f, an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C are formed.

[0354] Next, as Figure 5A shown, an organic compound film 103Rf is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the insulating layer 175. In addition, as Figure 5A shown, the organic compound film 103Rf is not formed on the conductive layer 152C.

[0355] Next, as Figure 5A shown, a conductive film 102Rf that will become the second electrode is formed on the organic compound film 103Rf, and then a sacrificial film 158Rf and a mask film 159Rf are formed on the conductive film 102Rf. By forming the sacrificial film 158Rf and the mask film 159Rf on the organic compound film 103Rf with the conductive film 102Rf interposed therebetween, the damage to the organic compound film 103Rf in the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0356] When the second electrode 102 is an electrode on the light extraction side, a material having transparency to visible light is preferably used as the conductive film 102Rf. For example, a conductive material having a reflectance of visible light of 20% or more and 80% or less, preferably 40% or more and 70% or less, and a resistivity of 1×10 -2 Ω·cm or less can be cited. In addition, when a material having low light transmittance such as a metal or an alloy is used as the conductive film 102Rf, it may be formed to a thickness that allows visible light to pass through (for example, a thickness of 1 nm to 10 nm). Specifically, in addition to an oxide conductor layer represented by ITO, it also includes an oxide semiconductor layer or an organic conductor layer containing an organic substance. As the organic conductor layer containing an organic substance, for example, a layer containing a composite material obtained by mixing an organic compound and an electron donor (donor), a layer containing a composite material obtained by mixing an organic compound and an electron acceptor (acceptor), etc. can be cited. In addition, the resistivity of the transparent conductive layer is preferably 1×10 5 Ω·cm or less, and more preferably 1×10 4 Ω·cm or less.

[0357] The conductive film 102Rf can be deposited by dry methods such as vacuum evaporation and sputtering, inkjet methods, spin coating methods, etc. In addition, it can also be formed by wet methods such as sol-gel methods or wet methods using pastes of metal materials. In particular, the conductive film 102Rf 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. For example, ALD method or vacuum evaporation method is preferably used.

[0358] In addition, the sacrificial film 158Rf and the mask film 159Rf are appropriately set as needed. For example, when the organic compound film 103Rf can be sufficiently protected by the conductive film 102Rf, the formation process of the sacrificial film 158Rf can be omitted by forming the mask film 159Rf on the conductive film 102Rf. Additionally, for example, when both the etching selectivity between the organic compound film 103Rf and the conductive film 102Rf and the etching selectivity between the conductive film 102Rf and the sacrificial film 158Rf are sufficiently large, the sacrificial film 158Rf can be used as a mask, so the formation process of the mask film 159Rf can also be omitted.

[0359] 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 with respect to the organic compound film 103Rf. As the mask film 159Rf, a film with a large etching selectivity with respect to the sacrificial film 158Rf is used.

[0360] Furthermore, the conductive film 102Rf, the sacrificial film 158Rf, and the mask film 159Rf are preferably 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 mask film 159Rf is typically 100°C or higher and 200°C or lower, preferably 100°C or higher and 150°C or lower, and more preferably 100°C or higher and 120°C or lower.

[0361] As the sacrificial film 158Rf and the mask film 159Rf, a film that can be removed by wet etching or dry etching is preferably used.

[0362] Note that the film quality of the sacrificial film 158Rf is preferably denser than that of the mask film 159Rf. For example, compared with the sputtering method, the ALD method or the vacuum evaporation method is more preferably used.

[0363] As the sacrificial film 158Rf and the mask film 159Rf, for example, one or more of a metal film, an alloy film, a metal oxide film, a semiconductor film, an organic insulating film, and an inorganic insulating film can be used.

[0364] 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. In particular, materials containing low melting point materials such as aluminum or silver are 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, the ultraviolet rays during pattern exposure can be suppressed from irradiating the organic compound film 103Rf, and thus the deterioration of the organic compound film 103Rf can be suppressed, so it is preferred.

[0365] 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), indium-tin oxide containing silicon, etc. can be used respectively.

[0366] Note that, instead of the above-mentioned gallium, 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) can also be used in the above-mentioned metal oxides.

[0367] As the sacrificial film 158Rf and the mask film 159Rf, semiconductor materials such as silicon or germanium are used, for example. This has a high affinity with the semiconductor manufacturing process, and thus is preferred. In addition, compounds containing the above-mentioned semiconductor materials can be used.

[0368] As the sacrificial film 158Rf and the mask film 159Rf, various inorganic insulating films can be used respectively. In particular, the adhesion of the oxide insulating film to the organic compound film 103Rf is higher than that of the nitride insulating film to the organic compound film 103Rf, so it is preferred.

[0369] Next, as Figure 5A shown, a resist mask 190R is formed. The resist mask 190R can be formed by coating a photosensitive material (photoresist) and then performing exposure and development.

[0370] The resist mask 190R is provided at a position overlapping with the conductive layer 152R. The resist mask 190R is preferably also provided at a position overlapping with the conductive layer 152C. Thereby, damage to the conductive layer 152C during the manufacturing process of the display device can be suppressed.

[0371] Next, as Figure 5B shown, a part of the mask film 159Rf is removed using the 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 called a hard mask) to remove a part of the sacrificial film 158Rf and a part of the conductive film 102Rf to form a sacrificial layer 158R and a second electrode 102R.

[0372] In this process, 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 conductive film 102Rf, 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 developer, an aqueous alkali solution such as an aqueous solution of tetramethylammonium hydroxide (TMAH), or an aqueous acid solution such as a liquid medicine of dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed liquid thereof.

[0373] In addition, when using the dry etching method in the processing of the sacrificial film 158Rf and the conductive film 102Rf, the deterioration of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0374] The resist mask 190R can be removed by the same method as the resist mask 191.

[0375] Next, as Figure 5B 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, and a part of the conductive film 102Rf and a part of the organic compound film 103Rf are removed, thereby forming the organic compound layer 103R.

[0376] Thus, as Figure 5B shown, a stacked structure of the organic compound layer 103R, the second electrode 102R, 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.

[0377] The processing of the organic compound film 103Rf is preferably performed using anisotropic etching. Anisotropic dry etching is particularly preferred. Alternatively, wet etching can also be used.

[0378] When using the dry etching method, the deterioration of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as the etching gas.

[0379] In addition, an oxygen-containing gas can 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, the damage to the organic compound film 103Rf can be suppressed. And, the adhesion of reaction products generated during etching and other defects can be suppressed.

[0380] When using a dry etching method, for example, it is preferable to use a gas containing one or more of the group 18 elements such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, He, and 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 can also be used as the etching gas.

[0381] Next, as Figure 6A shown, an organic compound film 103Gf that will later become the organic compound layer 103G and a conductive film 102Gf that will later become the second electrode 102G are formed.

[0382] The organic compound film 103Gf can be formed using the same method as that applicable to the formation of the organic compound film 103Rf. In addition, the organic compound film 103Gf can have the same structure as the organic compound film 103Rf. Further, the conductive film 102Gf can be formed using the same method as that applicable to the formation of the conductive film 102Gf. In addition, the conductive film 102Gf can have the same structure as the conductive film 102Rf.

[0383] Next, as Figure 6A shown, a sacrificial film 158Gf and a mask film 159Gf are sequentially formed. 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 applicable to 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 applicable to the resist mask 190R.

[0384] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0385] Next, as Figure 6B shown, a part of the mask film 159Gf is removed using the resist mask 190G, thereby forming a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Then, the resist mask 190G is removed. Next, using the mask layer 159G as a mask, a part of the sacrificial film 158Gf and a part of the conductive film 102Gf are removed, thereby forming a sacrificial layer 158G and a second electrode 102G. Next, the organic compound film 103Gf is processed to form the organic compound layer 103G.

[0386] Next, as Figure 6C shown, an organic compound film 103Bf and a conductive film 102Bf that will later become the second electrode 102B are formed.

[0387] The organic compound film 103Bf can be formed using the same method as that applicable to the formation of the organic compound film 103Rf. In addition, the organic compound film 103Bf can have the same structure as the organic compound film 103Rf. Further, the conductive film 102Bf can be formed using the same method as that applicable to the formation of the conductive film 102Rf. In addition, the conductive film 102Bf can have the same structure as the conductive film 102Rf.

[0388] Next, as Figure 6C shown, a sacrificial film 158Bf and a mask film 159Bf are formed in sequence. Then, a resist mask 190B is formed. The materials and formation method of the sacrificial film 158Bf and the mask film 159Bf are the same as the conditions applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation method of the resist mask 190B are the same as the conditions applicable to the resist mask 190R.

[0389] The resist mask 190B is provided at a position overlapping with the conductive layer 152B.

[0390] Next, as Figure 6D shown, a part of the mask film 159Bf is removed using the resist mask 190B, thereby forming a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. Then, the resist mask 190B is removed. Next, using the mask layer 159B as a mask, a part of the sacrificial film 158Bf and a part of the conductive film 102Bf are removed, thereby forming a sacrificial layer 158B and a second electrode 102B. Next, the organic compound film 103Bf is processed to form an organic compound layer 103B. For example, using the mask layer 159B and the sacrificial layer 158B as a hard mask, a part of the organic compound film 103Bf is removed, thereby forming the organic compound layer 103B.

[0391] Thus, as Figure 6D shown, a stacked structure of the organic compound layer 103B, the second electrode 102B, 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.

[0392] Note that the side surfaces of the stacked structures of the organic compound layer 103R and the second electrode 102R, the stacked structure of the organic compound layer 103G and the second electrode 102G, and the stacked structure of the organic compound layer 103B and the second electrode 102B are each preferably perpendicular or substantially perpendicular to the formation surface. For example, the angle formed by the formation surface and these side surfaces is preferably 60 degrees or more and 90 degrees or less.

[0393] As described above, the distance between two adjacent stacked structures among the stacked structures of the organic compound layer 103R and the second electrode 102R, the stacked structure of the organic compound layer 103G and the second electrode 102G, and the stacked structure of the organic compound layer 103B and the second electrode 102B formed by photolithography 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 end portions 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 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.

[0394] Next, as Figure 7A shown, it is preferable to remove 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.

[0395] Note that, in the case where the light-emitting devices are arranged in a so-called stripe configuration as Figure 24G shown, the second electrode 102 can be formed as a continuous layer among the light-emitting devices of the same light-emitting color. In this case, the auxiliary electrode 105 described later may not be formed, so in the case of bottom emission, the mask layer 159 may not be removed either, and after the Figure 6D process, the process of Figure 9B can be entered. In addition, in the case of top emission, when the sacrificial layer 158 and the mask layer 159 are light-transmissive, they may not be removed, and after the Figure 6D process, the process of Figure 9B can be entered. In the case where they are not light-transmissive, it is preferable to remove the sacrificial layer 158 and the mask layer 159. After removing the sacrificial layer 158 and / or the mask layer 159 (after the Figure 7A process), the process of Figure 9B can be entered.

[0396] As the process for removing the mask layer 159, the same method as the processing process of the mask film 159Rf can be used, and as the process for removing the sacrificial layer 158, the same method as the processing process of the sacrificial film 158Rf can be used. In particular, by using the wet etching method, compared with the case of using the dry etching method, the damage to the organic compound layer 103 during the removal of the mask layer can be reduced.

[0397] Alternatively, the mask layer can also be removed by dissolving it in a polar solvent such as water or alcohol. Examples of the alcohol include ethanol, methanol, isopropyl alcohol (IPA), or glycerol.

[0398] After removing the mask layer, a drying process can also be performed to remove the water on the surface. For example, a heat treatment can 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.

[0399] Next, as Figure 7B shown, an inorganic insulating film 125f is formed.

[0400] Next, as Figure 7C shown, an insulating film 127f that will later become the insulating layer 127 is formed on the inorganic insulating film 125f.

[0401] When forming the inorganic insulating film 125f and the insulating film 127f, the substrate temperature 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.

[0402] As the inorganic insulating film 125f, it is preferred 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.

[0403] The inorganic insulating film 125f is preferably formed by the ALD method, for example. By using the ALD method, deposition damage can be reduced, and a film with high coverage can be deposited, so it is preferred. As the inorganic insulating film 125f, an alumina film is preferably formed by the ALD method, for example.

[0404] 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.

[0405] Next, exposure is performed to sensitize a part of the insulating film 127f with visible light or ultraviolet light. The insulating layer 127 is formed in the region sandwiched between any two of the conductive layers 152R, 152G, and 152B and around the conductive layer 152C.

[0406] By means of the exposed area 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 with the top surface of the conductive layer 151.

[0407] The light for exposure preferably has an i-line (wavelength 365 nm). In addition, the light for exposure may also have at least one of a g-line (wavelength 436 nm) and an h-line (wavelength 405 nm).

[0408] Next, as Figure 8A shown, development is performed to remove the exposed area in the insulating film 127f to form the insulating layer 127a.

[0409] Next, as Figure 8B shown, the insulating layer 127a is used as a mask for an etching process to remove a part of the inorganic insulating film 125f. Thereby, an inorganic insulating layer 125 is formed under the insulating layer 127a. Hereinafter, the etching process using the insulating layer 127a as a mask is sometimes referred to as the first etching process.

[0410] The first etching process can be performed by dry etching or wet etching. Through the first etching process, the surfaces of the second electrodes 102R, 102B, and 102G are exposed.

[0411] When performing dry etching, a chlorine-based gas is preferably used. As the chlorine-based gas, one gas such as Cl2, BCl3, SiCl4, and CCl4 or a mixture of two or more of the above gases can be used. In addition, one gas such as 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.

[0412] As a dry etching apparatus, a dry etching apparatus having a high-density plasma source can be used. As a dry etching apparatus having a high-density plasma source, for example, an inductively coupled plasma (ICP) etching apparatus can be used. Alternatively, a capacitively coupled plasma (CCP) etching apparatus including parallel plate electrodes can be used.

[0413] In addition, it is preferable to perform the first etching process by wet etching. By using the wet etching method, the damage to the processed structure can be reduced compared with the case of using the dry etching method. For example, wet etching can be performed using an alkaline solution. For example, a TMAH aqueous solution as an alkaline solution can be used in the wet etching of an alumina film. In addition, an acidic solution containing fluoride can also be used. At this time, wet etching can be performed in a coated-gum manner.

[0414] Next, it is preferable to expose the entire substrate and irradiate visible light or ultraviolet light onto the insulating layer 127a. The energy density of this exposure is preferably greater than 0 mJ / cm 2 and is 800 mJ / cm 2 Hereinafter, it is more preferably greater than 0 mJ / cm 2 and is 500 mJ / cm 2 or less. 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.

[0415] Note that it is also possible to leave the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B unremoved and remaining in the process shown in Figure 7A . In this case, by providing an oxygen barrier insulating layer (for example, an alumina film, etc.) as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, oxygen diffusion into the second electrodes 102R, 102B, and 102G can be reduced or a decrease in conductivity due to metal oxidation can be suppressed.

[0416] 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 ( Figure 8C ) having a tapered shape on its side surface. 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 atmosphere. In addition, the heating atmosphere can be either an air atmosphere or a reduced-pressure atmosphere. 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.

[0417] Next, note that when the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B are not removed and remain in the process shown in Figure 7A , the insulating layer 127 is used as a mask, and an etching process is performed to remove a part of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. Thereby, openings are formed in each of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surfaces of the second electrodes 102R, 102G, and 102B and the conductive layer 152C are exposed. Note that hereinafter, this etching process is sometimes referred to as the second etching process.

[0418] Note that, in the case where the sacrificial layer 158 is not formed, since the surfaces of the second electrodes 102R, 102B, and 102G are exposed by the first etching process, the subsequent second etching process can be omitted.

[0419] In addition, the second etching process is performed using wet etching. By using the wet etching method, the damage to the organic compound layers 103R, 103G, and 103B can be reduced compared to the case of using the dry etching method. For example, the wet etching can be performed using an alkaline solution or an acidic solution. In order to prevent the dissolution of the organic compound layer 103, the wet etching is preferably performed using an aqueous solution.

[0420] Next, as Figure 9B shown, an auxiliary electrode 105 is formed on the second electrodes 102R, 102G, 102B, the conductive layer 152C, and the insulating layer 127. The auxiliary electrode 105 can be formed by a method such as sputtering or vacuum evaporation.

[0421] Next, as Figure 9B shown, a protective layer 131 is formed on the auxiliary electrode 105. The protective layer 131 can be formed by a method such as vacuum evaporation, sputtering, CVD method, or ALD method.

[0422] Next, the substrate 120 is bonded to the protective layer 131 using the resin layer 122, whereby a display device can be manufactured.

[0423] As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the island-shaped organic compound layers 103R, 103G, and 103B are not formed using a high-precision metal mask but are formed by depositing a film on one surface and then processing it, so that the island-shaped layers can be formed with a uniform thickness. And a high-definition display device or a display device with a high aperture ratio can be realized. In addition, even when 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 layers 103R, 103G, and 103B in adjacent sub-pixels. Therefore, it is possible to suppress the occurrence of leakage current between sub-pixels. As a result, it is possible to prevent crosstalk and realize a display device with extremely high contrast. In addition, even for a display device including a tandem light-emitting device manufactured by photolithography, a display device with good characteristics can be provided.

[0424] Embodiment 4 In this embodiment, a display device according to one aspect of the present invention will be described.

[0425] The display device of the present embodiment can be a high-definition display device. Therefore, for example, the display device of the present embodiment can be used as the display unit of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, and the display unit of wearable devices worn on the head such as VR devices like head-mounted displays (HMDs) and glasses-type AR devices.

[0426] In addition, the display device of the present embodiment can be a high-resolution display device or a large display device. Therefore, for example, the display device of the present embodiment can be used as the display unit of the following devices: electronic devices with a relatively large screen such as television devices, desktop or notebook personal computers, monitors for computers, digital signage, and large game machines such as pachinko machines; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game machines; portable information terminals; and sound reproduction devices.

[0427] [Display module] Figure 10A is a perspective view of the display module 280. The display module 280 includes a display device 100A and an FPC 290. Note that the display device included in the display module 280 is not limited to the display device 100A, and can also be any one of the display devices 100B and 100E to be described later.

[0428] The display module 280 includes a substrate 291 and a substrate 292. The display module 280 includes a display unit 281. The display unit 281 is the image display area in the display module 280, and light from each pixel provided in the following pixel unit 284 can be seen.

[0429] Figure 10B is a perspective schematic view of the structure on the side of the substrate 291. A circuit unit 282 is laminated on the substrate 291, a pixel circuit unit 283 on the circuit unit 282, and a pixel unit 284 on the pixel circuit unit 283. In addition, a terminal unit 285 for connecting to the FPC 290 is provided on a portion of the substrate 291 that does not overlap with the pixel unit 284. The terminal unit 285 and the circuit unit 282 are electrically connected through a wiring portion 286 composed of a plurality of wirings.

[0430] The pixel unit 284 includes a plurality of pixels 284a arranged periodically. Figure 10B The right side of shows an enlarged view of one pixel 284a. The pixel 284a can adopt various structures described in the above embodiment. Figure 10B shows a case where the pixel 284a has the same structure as the Figure 3A shown pixel 178.

[0431] The pixel circuit unit 283 includes a plurality of pixel circuits 283a arranged periodically.

[0432] A pixel circuit 283a controls the driving of a plurality of elements included in a pixel 284a.

[0433] The circuit section 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit section 283. For example, it preferably includes one or both of a gate line driving circuit and a source line driving circuit. In addition, it may also have at least one of an arithmetic circuit, a storage circuit, a power supply circuit, etc.

[0434] The FPC 290 serves as a wiring for supplying a video signal, a power supply potential, etc. from the outside to the circuit section 282. In addition, an IC may be mounted on the FPC 290.

[0435] The display module 280 may adopt a structure in which one or both of the pixel circuit section 283 and the circuit section 282 are laminated on the lower side of the pixel section 284, so the display section 281 can have an extremely high aperture ratio (effective display area ratio).

[0436] Such a high-definition display module 280 is suitable for VR devices such as HMDs or glasses-type AR devices. For example, because the display module 280 has an extremely high-definition display section 281, in the structure of viewing the display section of the display module 280 through a lens, even if the display section is magnified by the lens, the user will not see pixels, and thus a highly immersive display can be achieved. In addition, the display module 280 is not limited to this, and can also be applied to electronic devices with a relatively small display section.

[0437] [Display device 100A] Figure 11A The shown display device 100A includes a substrate 301, a light-emitting device 130, a capacitor 240, and a transistor 310.

[0438] The substrate 301 corresponds to Figure 10A and Figure 10B the substrate 291 in

[0439] The transistor 310 is a transistor having a channel formation region in the substrate 301. As the substrate 301, for example, a semiconductor substrate such as a single-crystalline silicon substrate can be used. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 is used as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and is used as a gate insulating layer. The low-resistance region 312 is a region in the substrate 301 doped with impurities and is used as a source or a drain. The insulating layer 314 covers the side surface of the conductive layer 311.

[0439] In addition, between two adjacent transistors 310, an element isolation layer 315 is provided in a manner of being embedded in the substrate 301.

[0440] In addition, an insulating layer 261 is provided so as to cover the transistor 310, and a capacitor 240 is provided on the insulating layer 261.

[0441] The capacitor 240 includes a conductive layer 241, a conductive layer 245, and an insulating layer 243 therebetween. The conductive layer 241 serves as one electrode of the capacitor 240, the conductive layer 245 serves as the other electrode of the capacitor 240, and the insulating layer 243 serves as the dielectric of the capacitor 240.

[0442] The conductive layer 241 is provided on the insulating layer 261 and is embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and drain of the transistor 310 through a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided so as to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping the conductive layer 241 with the insulating layer 243 therebetween.

[0443] An insulating layer 255 is provided so as to cover the capacitor 240, an insulating layer 174 is provided on the insulating layer 255, and an insulating layer 175 is provided on the insulating layer 174. A light-emitting device 130R, a light-emitting device 130G, and a light-emitting device 130B are provided on the insulating layer 175. An insulator is provided in a region between adjacent light-emitting devices.

[0444] The insulating layer 156R is provided so as to include a region overlapping the side surface of the conductive layer 151R, the insulating layer 156G is provided so as to include a region overlapping the side surface of the conductive layer 151G, and the insulating layer 156B is provided so as to include a region overlapping the side surface of the conductive layer 151B. In addition, a conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. Note that the insulating layer 156 may not be provided.

[0445] The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B are electrically connected to one of the source and drain of the transistor 310 through plugs 256 embedded in the insulating layers 243, 255, 174, and 175, the conductive layer 241 embedded in the insulating layer 254, and the plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the plugs.

[0446] In addition, a protective layer 131 is provided on the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B with an auxiliary electrode 105 therebetween. A resin layer 122 adheres the substrate 120 to the protective layer 131. Details of the components from the light-emitting device 130 to the substrate 120 can be referred to in Embodiment 3. The substrate 120 corresponds to Figure 10Asubstrate 292.

[0447] Figure 11B shows Figure 11A A modified example of the display device 100A shown. Figure 11B The display device shown includes a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B, and the light-emitting device 130 has an area overlapping one of the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. In Figure 11B In the display device shown, the light-emitting device 130 can emit white light, for example. In addition, for example, the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B can transmit red light, green light, and blue light, respectively.

[0448] [Display device 100B] Figure 12 A perspective view showing the display device 100B is Figure 13 A cross-sectional view showing the display device 100C is

[0449] The display device 100B has a structure in which a bonding substrate 352 and a substrate 351 are bonded. In Figure 12 The bonding substrate 352 is indicated by a dashed line.

[0450] The display device 100B includes a pixel portion 177, a connection portion 140, a circuit 356, a wiring 355, etc. Figure 12 An example in which the display device 100B is mounted with an IC 354 and an FPC 353 is shown. Therefore, it is also possible to Figure 12 The structure shown can also be referred to as a display module including the display device 100B, an IC (integrated circuit), and an FPC. Here, the substrate of the display device on which a connector such as an FPC is mounted or the substrate on which an IC is mounted is called a display module.

[0451] The connection portion 140 is provided outside the pixel portion 177. The connection portion 140 can be one or more. In the connection portion 140, the common electrode of the light-emitting device is electrically connected to the conductive layer, and power can be supplied to the common electrode.

[0452] As the circuit 356, for example, a scan line driving circuit can be used.

[0453] The wiring 355 has a function of supplying signals and power to the pixel portion 177 and the circuit 356. The signals and power are input to the wiring 355 from the outside via the FPC 353 or input to the wiring 355 from the IC 354.

[0454] Figure 12An example of setting the IC 354 on the substrate 351 by means of COG (Chip On Glass) or COF (Chip on Film) is shown. As the IC 354, for example, an IC including a scan line driving circuit or a signal line driving circuit can be used. Note that the display device 100B and the display module do not necessarily have to be provided with an IC. In addition, for example, the IC can also be mounted on the FPC by means of COF.

[0455] Figure 13 An example of a cross-section showing a part of the region including the FPC 353, a part of the circuit 356, a part of the pixel portion 177, a part of the connection portion 140, and a part of the region including the end portion of the display device 100B is shown.

[0456] [Display device 100C] Figure 13 The shown display device 100C includes a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc. between the substrate 351 and the substrate 352.

[0457] Details of the light-emitting device 130R, the light-emitting device 130G, and the light-emitting device 130B can be referred to in Embodiment 1 or Embodiment 2.

[0458] The light-emitting device 130R includes a conductive layer 224R, a conductive layer 151R on the conductive layer 224R, and a conductive layer 152R on the conductive layer 151R. The light-emitting device 130G includes a conductive layer 224G, a conductive layer 151G on the conductive layer 224G, and a conductive layer 152G on the conductive layer 151G. The light-emitting device 130B includes a conductive layer 224B, a conductive layer 151B on the conductive layer 224B, and a conductive layer 152B on the conductive layer 151B.

[0459] The conductive layer 224R is connected to the conductive layer 222b included in the transistor 205 through an opening provided in the insulating layer 214. The end portion of the conductive layer 151R is located outside the end portion of the conductive layer 224R. The insulating layer 156R is provided in a manner that includes a region in contact with the side surface of the conductive layer 151R, and the conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R.

[0460] The conductive layer 224G, the conductive layer 151G, the conductive layer 152G, the insulating layer 156G in the light-emitting device 130G, and the conductive layer 224B, the conductive layer 151B, the conductive layer 152B, the insulating layer 156B in the light-emitting device 130B are the same as those in the conductive layer 224R, the conductive layer 151R, the conductive layer 152R, and the insulating layer 156R in the light-emitting device 130R, so detailed description thereof is omitted.

[0461] Recesses are formed in the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B so as to cover the openings formed in the insulating layer 214. The recesses are filled with the layer 128.

[0462] The layer 128 has a function of planarizing the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B. The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B which are electrically connected to the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B are provided on the conductive layer 224R, the conductive layer 224G, the conductive layer 224B, and the layer 128. Therefore, the region overlapping with the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B can also be used as a light-emitting region, and the aperture ratio of the pixel can be increased.

[0463] The layer 128 can also be an insulating layer or a conductive layer. The layer 128 can appropriately use various inorganic insulating materials, organic insulating materials, and conductive materials. In particular, the layer 128 is preferably formed of an insulating material, and more preferably formed of an organic insulating material. For example, the layer 128 can use the organic insulating material that can be used for the insulating layer 127 described above.

[0464] A protective layer 131 is provided on the light-emitting devices 130R, the light-emitting devices 130G, and the light-emitting devices 130B with the auxiliary electrode 105 interposed therebetween. The protective layer 131 and the substrate 352 are bonded by the bonding layer 142. The substrate 352 is provided with a light-shielding layer 157. The light-emitting device 130 can be sealed by a solid sealing structure or a hollow sealing structure, etc. In Figure 13 this case, the space between the substrate 352 and the substrate 351 is filled with the bonding layer 142, that is, a solid sealing structure is adopted. Alternatively, this space can also be filled with an inert gas (such as nitrogen or argon), that is, a hollow sealing structure is adopted. At this time, the bonding layer 142 can also be provided in a manner that does not overlap with the light-emitting device. In addition, this space can also be filled with a resin different from the bonding layer 142 provided in a frame shape.

[0465] Figure 13 An example is shown in which the connection portion 140 includes a conductive layer 224C obtained by processing the same conductive film as the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, a conductive layer 151C obtained by processing the same conductive film as the conductive layer 151R, the conductive layer 151G, and the conductive layer 151B, and a conductive layer 152C obtained by processing the same conductive film as the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B. In addition, Figure 13 an example is shown in which the insulating layer 156C is provided in a manner that includes a region overlapping with the side surface of the conductive layer 151C.

[0466] The display device 100C is a top-emission display device. The light-emitting device emits light to the side of the substrate 352. The substrate 352 is preferably made of a material with high visible light transmittance. The pixel electrode contains a material that reflects visible light, and the counter electrode (second electrode 102) and the auxiliary electrode 105 contain materials that transmit visible light.

[0467] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are sequentially provided on the substrate 351. A part of the insulating layer 211 serves as a gate insulating layer for each transistor. A part of the insulating layer 213 serves as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistors. The insulating layer 214 is provided to cover the transistors and serves as a planarization layer. In addition, there is no particular limitation on the number of gate insulating layers and the number of insulating layers covering the transistors, and it can be either one or two or more.

[0468] Preferably, an inorganic insulating film is used as the insulating layer 211, the insulating layer 213, and the insulating layer 215.

[0469] Preferably, an organic insulating layer is used as the insulating layer 214 serving as a planarization layer.

[0470] The transistors 201 and 205 include: a conductive layer 221 serving as a gate; an insulating layer 211 serving as a gate insulating layer; conductive layers 222a and 222b serving as source and drain electrodes; a semiconductor layer 231; an insulating layer 213 serving as a gate insulating layer; and a conductive layer 223 serving as a gate.

[0471] A connection portion 204 is provided in a region of the substrate 351 not overlapped by the substrate 352. In the connection portion 204, the source electrode or the drain electrode of the transistor 201 is electrically connected to the FPC 353 through the conductive layer 166 and the connection layer 242. An example is shown where the conductive layer 166 has a stacked structure of a conductive film obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. The conductive layer 166 is exposed on the top surface of the connection portion 204. Therefore, the connection portion 204 can be electrically connected to the FPC 353 through the connection layer 242.

[0472] Preferably, a light-shielding layer 157 is provided on the surface of the substrate 351 on the side of the substrate 352. The light-shielding layer 157 can be provided between adjacent light-emitting devices, in the connection portion 140, the circuit 356, etc. In addition, various optical members can be arranged outside the substrate 352.

[0473] The substrate 351 and the substrate 352 can each be made of materials that can be used for the substrate 120.

[0474] As the adhesive layer 142, materials that can be used for the resin layer 122 can be used.

[0475] As the connection layer 242, an anisotropic conductive film (ACF: Anisotropic Conductive Film), an anisotropic conductive paste (ACP: Anisotropic Conductive Paste), etc. can be used.

[0476] [Display device 100D] Figure 14 The shown display device 100D Figure 13 The main difference from the shown display device 100C is that the display device 100D is a bottom-emission type display device.

[0477] The light emitted by the light-emitting device is emitted to the side of the substrate 351. The substrate 351 is preferably made of a material having high transmittance to visible light. On the other hand, there is no limitation on the light transmittance of the material for the substrate 352.

[0478] It is preferable to form a light-shielding layer between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205. Figure 14 An example is shown in which a light-shielding layer 317 is provided on the substrate 351, an insulating layer 153 is provided on the light-shielding layer 317, and transistors 201, 205, etc. are provided on the insulating layer 153.

[0479] The light-emitting device 130R includes a conductive layer 112R, a conductive layer 126R on the conductive layer 112R, and a conductive layer 129R on the conductive layer 126R.

[0480] The light-emitting device 130B includes a conductive layer 112B, a conductive layer 126B on the conductive layer 112B, and a conductive layer 129B on the conductive layer 126B.

[0481] The conductive layers 11, 112B, 126R, 126B, 129R, 129B all use materials having high transmittance to visible light. As the second electrode 102, a material that reflects visible light is preferably used.

[0482] Note that although Figure 14 the light-emitting device 130G is not shown in, the light-emitting device 130G is also provided.

[0483] In addition, Figure 14 etc. show examples in which the top surface of the layer 128 has a flat portion, but the shape of the layer 128 is not particularly limited.

[0484] [Display device 100D2] Figure 15A The display device 100D2 shown is an example of a bottom-emitting display device different from Figure 14 the display device 100D shown. The display device 100D2 differs from the display device 100D in that it includes an organic resin layer 180. In the drawings, the symbols of the same constituent elements are sometimes omitted, and the detailed content can be referred to Figure 14 the description of Figure 14 .

[0485] In addition, Figure 15B a plan view layout of pixels 178 (pixels 178a and 178b) including sub-pixels 110 (sub-pixels 110R, sub-pixels 110G, and sub-pixels 110B) is shown, Figure 15C and a plan view of the organic resin layer 180 in a region where the sub-pixels 110R and 110G included in the pixel 178 are formed is shown. In addition, the width 110Rw of the light-emitting region is between the light-shielding layers 317 in the sub-pixel 110R.

[0486] As Figure 15A shown, the organic resin layer 180 is provided on the insulating layer 214. As Figure 15A the region surrounded by the dotted line in Figure 15C and

[0487] shown, the organic resin layer 180 includes concave portions 181 (concave portions 181a and 181b) having curved surfaces at least in the region where the sub-pixels are formed. In addition, the concave portion 181 may be provided outside the light-emitting region as in the concave portion 181c. By providing the concave portion 181c, the light emission generated in the region overlapping with the light-shielding layer 317 or the light entering the region overlapping with the light-shielding layer 317 can be refracted and extracted from the light-emitting region to the outside, thereby improving the light emission efficiency.

[0488] In addition, Figure 15A and Figure 15C show an example in which the top surface shape of the concave portion is a hexagon ( Figure 15C ), and the cross-sectional shape is a semi-circle ( Figure 15A ). Other shapes may be adopted as needed. For example, the top surface shape of the concave portion may also be a polygon such as a triangle, a quadrilateral (including a rectangle and a square), a pentagon, etc., a polygon with rounded corners, an ellipse, or a circle.

[0489] The organic resin layer 180 can use an insulating layer containing an organic material. For example, the organic resin layer 180 can use an acrylic resin, a polyimide resin, an epoxy resin, an imide resin, a polyamide resin, a polyimide amide resin, a silicone resin, a siloxane resin, a benzocyclobutene resin, a phenolic resin, and precursors of the above resins, etc. In addition, the organic resin layer 180 can also use organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0490] In addition, the organic resin layer 180 can use a photosensitive resin. The photosensitive resin can use a photoresist. The photosensitive resin can use a positive-type material or a negative-type material.

[0491] The organic resin layer 180 can contain a material that absorbs visible light. For example, the organic resin layer 180 itself can be composed of a material that absorbs visible light, and the organic resin layer 180 can also contain a pigment that absorbs visible light. The organic resin layer 180 can use, for example, the following resins: a resin that can be used as a color filter that transmits red, blue, or green light and absorbs other light; or a resin that contains carbon black as a pigment and is used as a black matrix; etc.

[0492] In addition, there is a first electrode 101 on the organic resin layer 180, an organic compound layer 103 on the first electrode 101, and a second electrode 102 on the organic compound layer 103. The ends of the first electrode 101, the organic compound layer 103, and the second electrode 102 can also be covered by an insulating layer 127.

[0493] In addition, the first electrode 101 formed on the organic resin layer 180 also has a recess along the recess of the organic resin layer 180. In addition, the organic compound layer 103 formed on the first electrode 101 also has a recess along the recess of the first electrode 101. In addition, the second electrode 102 formed on the organic compound layer 103 also has a recess along the recess of the organic compound layer 103. In addition, the auxiliary electrode 105 formed on the second electrode 102 also has a recess along the recess of the second electrode 102. That is to say, the recesses of the organic resin layer 180, the first electrode 101, the organic compound layer 103, the second electrode 102, and the auxiliary electrode 105 have an overlapping structure with each other.

[0494] In addition, there is a second electrode 102 on the organic compound layer 103 and the insulating layer 127, and an auxiliary electrode 105 on the second electrode 102. A protective layer 131 is provided on the auxiliary electrode 105 and is bonded to the substrate 352 through an adhesive layer 142.

[0495] In addition, although Figures 15A to 15C the light-emitting device 130B is not shown, the light-emitting device 130B is provided.

[0496] Since the light-emitting device according to one embodiment of the present invention including the above-mentioned organic resin layer 180 has the structure described in Embodiment 1 or Embodiment 2, an organic semiconductor device with a low driving voltage and good characteristics can be provided.

[0497] [Display device 100E] Figure 16 The shown display device 100E is Figure 13 a modified example of the shown display device 100C. The main difference between the display device 100E and the display device 100C is that the display device 100E includes a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B.

[0498] In the display device 100E, the light-emitting device 130 has an area overlapping one of the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. The coloring layer 132R, the coloring layer 132G, and the coloring layer 132B may be provided on the surface of the substrate 351 on the side of the substrate 352. The ends of the coloring layer 132R, the ends of the coloring layer 132G, and the ends of the coloring layer 132B may overlap the light-shielding layer 157.

[0499] In the display device 100E, for example, the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B may transmit red light, green light, and blue light, respectively. In addition, the display device 100E may also adopt a structure in which the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B are provided between the protective layer 131 and the adhesive layer 142.

[0500] [Display device 100E2] Figure 17A The shown display device 100E2 is Figure 16 a modified example of the shown display device 100E, and there are microlenses 182 on the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. In addition, the symbols of the same components may sometimes be omitted in the drawings, and the detailed description thereof may be referred to Figure 16 the description of Figure 16 .

[0501] In addition, Figure 17B a top view layout showing pixels 178 (pixels 178a and 178b) including sub-pixels 110 (sub-pixel 110R, sub-pixel 110G, sub-pixel 110B) is shown, Figure 17C a top view showing microlenses 182 in the area where the sub-pixel 110R and the sub-pixel 110G included in the pixel 178 are formed is shown. In addition, the width 110Gw of the light-emitting area corresponds to the area where the second electrode 102 contacts the organic compound layer 103 in the sub-pixel 110G.

[0502] Figure 17A In the display device 100E2 shown, a planarization film 143 is provided on the protective layer 131, and planarization films 144 are provided on the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. A microlens 182 is provided on the planarization film 144.

[0503] In addition, as Figure 17C shown, microlenses 182 can be provided in each sub-pixel in the region where the sub-pixels are formed.

[0504] In addition, Figure 17C an example in which the top surface shape of the microlens 182 is hexagonal is shown in, and other shapes can also be adopted as needed. For example, the top surface shape of the concave portion can also be a polygon such as a triangle, a quadrilateral (including a rectangle and a square), a pentagon, etc., a polygon with rounded corners, an ellipse, or a circle.

[0505] The microlens 182 can be formed using the same material as the organic resin layer 180.

[0506] This embodiment can be appropriately combined with other embodiments or examples. In addition, in this specification, when multiple structural examples are shown in one embodiment, the structural examples can be appropriately combined.

[0507] Embodiment 5 In this embodiment, an electronic device of one aspect of the present invention will be described.

[0508] The electronic device of this embodiment includes a display device of one aspect of the present invention in a display unit. The display device of one aspect of the present invention has high display performance and is easily high-definition and high-resolution. Therefore, it can be used for the display units of various electronic devices.

[0509] As electronic devices, for example, in addition to electronic devices with relatively large screens such as television sets, desktop or notebook personal computers, monitors for computers, digital signage, and large game machines such as pachinko machines, digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, portable information terminals, and sound reproduction devices can also be cited.

[0510] In particular, since the display device of one aspect of the present invention can improve clarity, it can be suitably used for electronic devices including relatively small display units. Examples of such electronic devices include watch-type and bracelet-type information terminal devices (wearable devices), wearable devices that can be worn on the head such as VR devices such as head-mounted displays, and AR devices and MR devices of the glasses type.

[0511] The electronic device according to this embodiment may also include a sensor having a function of measuring factors such as force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electric power, radiation, flow rate, humidity, inclination, vibration, odor, or infrared rays).

[0512] Refer to Figures 18A to 18D An example of a wearable device that can be worn on the head will be described.

[0513] Figure 18A The illustrated electronic device 700A and Figure 18B The illustrated electronic device 700B both include a pair of display panels 751, a pair of outer casings 721, a communication unit (not illustrated), a pair of mounting portions 723, a control unit (not illustrated), an imaging unit (not illustrated), a pair of optical members 753, a frame 757, and a pair of nose pads 758.

[0514] The display panel 751 may apply the display device of one aspect of the present invention. Thereby, a highly reliable electronic device can be realized.

[0515] Both the electronic device 700A and the electronic device 700B can project the image displayed on the display panel 751 onto the display area 756 in the optical member 753. Since the optical member 753 has translucency, the user can see the image displayed in the display area overlapping with the transmitted image seen through the optical member 753.

[0516] A camera capable of photographing the front may also be provided as the imaging unit on the electronic device 700A and the electronic device 700B. In addition, by providing an acceleration sensor such as a gyro sensor on the electronic device 700A and the electronic device 700B, the orientation of the user's head can be detected and the image corresponding to the direction can be displayed on the display area 756.

[0517] The communication unit has a wireless communication device, and an image signal can be supplied through the wireless communication device, for example. In addition, instead of the wireless communication device or in addition to the wireless communication device, a connector capable of connecting a cable for supplying an image signal and a power potential may be included.

[0518] In addition, the electronic device 700A and the electronic device 700B are provided with a battery and can be charged in one or both of a wireless manner and a wired manner.

[0519] The outer casing 721 may also be provided with a touch sensor module.

[0520] As a touch sensor module, various touch sensors can be used. For example, various methods such as the capacitive method, the resistive film method, the infrared method, the electromagnetic induction method, the surface acoustic wave method, and the optical method can be adopted. In particular, it is preferable to apply a sensor of the capacitive method or the optical method to the touch sensor module.

[0521] Figure 18C The electronic device 800A shown and Figure 18D The electronic device 800B shown both include a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0522] The display unit 820 can apply a display device according to one aspect of the present invention. Thus, a highly reliable electronic device can be realized.

[0523] The display unit 820 is disposed at a position inside the housing 821 where it can be seen through the lens 832. In addition, by displaying different images on each of the pair of display units 820, three-dimensional display using parallax can be performed.

[0524] The electronic device 800A and the electronic device 800B preferably have a mechanism in which the left and right positions of the lens 832 and the display unit 820 can be adjusted so that the lens 832 and the display unit 820 are located at the most suitable positions according to the position of the user's eyes.

[0525] The user can mount the electronic device 800A or the electronic device 800B on the head using the mounting unit 823.

[0526] The imaging unit 825 has a function of acquiring external information. The data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used in the imaging unit 825. In addition, a plurality of cameras can also be provided to be able to correspond to various perspectives such as telephoto and wide angle.

[0527] The electronic device 800A may also include a vibration mechanism used as a bone conduction headphone.

[0528] The electronic device 800A and the electronic device 800B may both include input terminals. A cable for supplying an image signal from an image output device or the like and power for charging a battery provided in the electronic device can be connected to the input terminals.

[0529] An electronic device according to one aspect of the present invention may also have a function of performing wireless communication with the headphone 750.

[0530] In addition, the electronic device may also include a headphone unit. Figure 18BThe illustrated electronic device 700B includes a headphone unit 727. A part of the wiring connecting the headphone unit 727 and the control unit may also be disposed inside the housing 721 or the mounting portion 723.

[0531] Similarly, Figure 18D The illustrated electronic device 800B includes a headphone unit 827. For example, a structure in which the headphone unit 827 and the control unit 824 are connected in a wired manner may be employed.

[0532] Thus, as an electronic device according to one aspect of the present invention, both the glasses type (such as the electronic devices 700A and 700B) and the goggles type (such as the electronic devices 800A and 800B) are preferred.

[0533] Figure 19A The illustrated electronic device 6500 is a portable information terminal device that can be used as a smart phone.

[0534] The electronic device 6500 includes a housing 6501, a display unit 6502, a power button 6503, a button 6504, a speaker 6505, a microphone 6506, a camera 6507, a light source 6508, and the like. The display unit 6502 has a touch panel function.

[0535] The display unit 6502 may use a display device according to one aspect of the present invention. Thereby, a highly reliable electronic device can be realized.

[0536] Figure 19B It is a schematic cross-sectional view of an end portion on the microphone 6506 side including the housing 6501.

[0537] A protective member 6510 having translucency is provided on the display surface side of the housing 6501, and a display panel 6511, an optical member 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, and the like are provided in a space surrounded by the housing 6501 and the protective member 6510.

[0538] The display panel 6511, the optical member 6512, and the touch sensor panel 6513 are fixed to the protective member 6510 using an adhesive layer (not shown).

[0539] In a region outside the display unit 6502, a part of the display panel 6511 is folded back, and an FPC 6515 is connected to the folded-back part. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on the printed circuit board 6517.

[0540] The display panel 6511 can use the light-emitting device of one embodiment of the present invention. Thus, an extremely lightweight electronic device can be realized. In addition, since the display panel 6511 is extremely thin, a large-capacity battery 6518 can be installed while suppressing the thickness of the electronic device. Further, by folding a part of the display panel 6511 to provide a connection portion with the FPC 6515 on the back surface of the pixel portion, a narrow-bezel electronic device can be realized.

[0541] Figure 19C An example of a television device is shown. In the television device 7100, a display unit 7000 is assembled in a housing 7171. A structure in which the housing 7171 is supported by a bracket 7173 is shown here.

[0542] The display unit 7000 can use the display device of one embodiment of the present invention. Thus, a highly reliable electronic device can be realized.

[0543] It is possible to perform Figure 19C the operation of the television device 7100 shown by using the operation switch provided in the housing 7171 and the separately provided remote control unit 7151.

[0544] Figure 19D An example of a notebook personal computer is shown. The notebook personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, an external connection port 7214, etc. A display unit 7000 is assembled in the housing 7211.

[0545] The display unit 7000 can use the display device of one embodiment of the present invention. Thus, a highly reliable electronic device can be realized.

[0546] Figure 19E and Figure 19F An example of a digital sign is shown.

[0547] Figure 19E The digital sign 7300 shown includes a housing 7301, a display unit 7000, a speaker 7303, etc. In addition, it may further include an LED lamp, operation keys (including a power switch or an operation switch), connection terminals, various sensors, a microphone, etc.

[0548] Figure 19F An example of a digital sign 7400 provided on a cylindrical column 7401 is shown The digital sign 7400 includes a display unit 7000 provided along the curved surface of the column 7401.

[0549] In Figure 19E and Figure 19F , the display device of one embodiment of the present invention can be used for the display unit 7000. Thus, a highly reliable electronic device can be realized.

[0550] The larger the display unit 7000 is, the more information can be provided at one time. The larger the display unit 7000 is, the more likely it is to attract people's attention. For example, it can improve the advertising effect.

[0551] As Figure 19E and Figure 19F shown, the digital signage 7300 or the digital signage 7400 can preferably be linked with the information terminal devices 7311 or 7411 such as smartphones carried by users through wireless communication.

[0552] Figures 20A to 20G The electronic device shown includes a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), connection terminals 9006, a sensor 9007 (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, inclination, vibration, odor or infrared ray), a microphone 9008, etc.

[0553] Figures 20A to 20G The electronic device shown has various functions. For example, it can have the following functions: the function of displaying various information (such as static images, dynamic images, and text images) on the display unit; the function of a touch panel; the function of displaying a calendar, date, or time, etc.; the function of controlling and processing through the use of various software (programs); the function of performing wireless communication; the function of reading out and processing programs or data stored in a storage medium; etc.

[0554] Next, the electronic device shown will be described in detail. Figures 20A to 20G The electronic device shown.

[0555] Figure 20A is a perspective view showing the portable information terminal 9171. The portable information terminal 9171 can be used as a smartphone, for example. Note that in the portable information terminal 9171, a speaker 9003, connection terminals 9006, a sensor 9007, etc. can also be provided. In addition, as the portable information terminal 9171, text or image information can be displayed on its multiple faces. In Figure 20A an example of displaying three icons 9050 is shown. In addition, the information 9051 shown by a dotted rectangle can be displayed on other faces of the display unit 9001. As an example of the information 9051, information such as a prompt for receiving an email, SNS, phone call, etc.; the title of an email or SNS, etc.; the sender's name of an email or SNS, etc.; date; time; battery level; and radio wave intensity, etc. can be cited. Or, icons 9050, etc. can be displayed at the position where the information 9051 is displayed.

[0556] Figure 20B It is a perspective view showing the portable information terminal 9172. The portable information terminal 9172 has a function of displaying information on three or more surfaces of the display unit 9001. Here, an example is shown in which the information 9052, the information 9053, and the information 9054 are respectively displayed on different surfaces. For example, in a state where the portable information terminal 9172 is placed in an upper pocket, the user can confirm the information 9053 displayed at a position seen from above the portable information terminal 9172.

[0557] Figure 20C It is a perspective view showing the tablet terminal 9173. The tablet terminal 9173 can execute various application software such as mobile phones, reading and editing of emails and articles, playing music, network communication, and computer games, for example. The tablet terminal 9173 includes a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front surface of the housing 9000, an operation key 9005 serving as an operation button on the left side surface of the housing 9000, and a connection terminal 9006 on the bottom surface.

[0558] Figure 20D It is a perspective view showing the watch-type portable information terminal 9200. The portable information terminal 9200 can be used as a smart watch (registered trademark), for example. In addition, the display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. Furthermore, the portable information terminal 9200 can perform hands-free calls by communicating with a headset capable of wireless communication, for example. In addition, by using the connection terminal 9006, the portable information terminal 9200 can perform data transmission with other information terminals or be charged. Charging can also be performed by wireless power supply.

[0559] Figures 20E to 20G It is a perspective view showing the foldable portable information terminal 920I.In addition, Figure 20E It is a perspective view of the state in which the portable information terminal 9201 is unfolded, Figure 20G It is a perspective view of the folded state, Figure 20F It is from Figure 20E of the state and Figure 20G of the state when converting from one to the other, it is a perspective view of an intermediate state. The portable information terminal 9201 has good portabil...

Claims

1. A light-emitting device, comprising: A first electrode; A second electrode; And An organic compound layer, Wherein the first electrode, the second electrode, and the organic compound layer are located on a first insulating layer, The first electrode is in contact with the first insulating layer, The organic compound layer is located between the first electrode and the second electrode, The second electrode and the organic compound layer are separated from at least one of other multiple light-emitting devices adjacent to the light-emitting device, When viewed from a direction perpendicular to the surface of the first insulating layer, the contour of the second electrode coincides with or is substantially consistent with the contour of the organic compound layer, The organic compound layer includes a light-emitting layer and an electron injection layer, The electron injection layer is a mixed layer containing a metal or an oxide of the metal, a first organic compound, and a second organic compound, The first organic compound contains a first π-deficient heteroaromatic ring having an electron-donating group, The second organic compound contains a second π-deficient heteroaromatic ring, And the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by 0.20 eV or more.

2. The light-emitting device according to claim 1, Wherein the organic compound layer includes a P-type layer between the electron injection layer and the second electrode, And the P-type layer contains a fifth organic compound having hole-transporting properties and a second metal oxide or a sixth organic compound containing at least one of a halogen group and a cyano group.

3. A light-emitting device, which is one of multiple light-emitting devices included in a group of light-emitting devices, and the group of light-emitting devices includes: A first electrode group on the same insulating surface; A second electrode group opposite to the first electrode group; And A first layer group between the first electrode group and the second electrode group, Wherein the light-emitting device includes a first electrode, a second electrode, and a first layer, The first electrode is one of the electrodes in the first electrode group, The first electrodes of the multiple light-emitting devices are independent of each other, The first layer is one of the layers in the first layer group, The first layers of the multiple light-emitting devices are independent of each other, The second electrode is one of the electrodes in the second electrode group, The second electrodes of the multiple light-emitting devices are independent of each other, The second electrode and the first layer overlap with the first electrode, The first layer includes a light-emitting layer and an electron injection layer, The electron injection layer is a mixed layer containing a metal or an oxide of the metal, a first organic compound, and a second organic compound, The first organic compound contains a first π-deficient heteroaromatic ring having an electron-donating group, The second organic compound contains a second π-deficient heteroaromatic ring, The LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by 0.20 eV or more, And the interval between the first layer in the light-emitting device and the first layer in other light-emitting devices adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

4. The light-emitting device according to claim 3, Wherein the first layer includes a P-type layer between the electron injection layer and the second electrode, And the P-type layer contains a fifth organic compound having hole-transporting properties and a second metal oxide or a sixth organic compound containing at least one of a halogen group and a cyano group.

5. The light-emitting device according to claim 3, wherein when viewed in a direction perpendicular to the insulating plane, the contour of the second electrode coincides with or substantially coincides with the contour of the first layer.

6. The light-emitting device according to claim 3, wherein the end of the cross-section of the second electrode coincides with the end of the cross-section of the first layer in a direction perpendicular to or substantially perpendicular to the insulating plane.

7. The light-emitting device according to claim 1, wherein when the LUMO energy level of the first organic compound is LUMO1 (eV) and the LUMO energy level of the second organic compound is LUMO2 (eV), the relationship LUMO1 - 0.80 ≤ LUMO2 ≤ LUMO1 - 0.20 is satisfied.

8. The light-emitting device according to claim 1, wherein the first π-deficient heteroaromatic ring is a heteroaromatic ring containing two or more pyridine rings.

9. The light-emitting device according to claim 1, wherein the acidity coefficient pK of the first organic compound a is 8 or more.

10. The light-emitting device according to claim 1, wherein the first π-deficient heteroaromatic ring is different from the second π-deficient heteroaromatic ring.

11. The light-emitting device according to claim 1, wherein the second organic compound contains at least one of an imidazole ring, a pyrazole ring, an oxazole ring, a thiazole ring, a triazole ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, and a triazine ring.

12. The light-emitting device according to claim 1, wherein the acidity coefficient pK of the second organic compound a is less than 4.

13. The light-emitting device according to claim 1, wherein the light-emitting layer contains a third organic compound, the third organic compound contains a third π-deficient heteroaromatic ring, and the third π-deficient heteroaromatic ring is the same as the second π-deficient heteroaromatic ring.

14. The light-emitting device according to claim 1, wherein the light-emitting layer contains a third organic compound, and the third organic compound is the same as the second organic compound.

15. The light-emitting device according to claim 13, wherein the organic compound layer includes an electron transport layer between the light-emitting layer and the electron injection layer, the electron transport layer contains a fourth organic compound, and the fourth organic compound is different from the third organic compound.

16. The light-emitting device according to claim 1, wherein the metal belongs to any group among Group 3, Group 11, and Group 13 of the periodic table.

17. The light-emitting device according to claim 1, wherein the electron-donating group is one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heteroaromatic amino group.

18. The light-emitting device according to claim 1, wherein when the threshold value of the electron density distribution in atomic units is 0.0004 e / a0 3 the minimum value of the electrostatic potential of the first organic compound is -0.085 E h or less.

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