Light emitting device

Abstract

Provided is a light-emitting device having good reliability. Provided is a light emitting device including a first electrode, a second electrode, and an EL layer. The EL layer is located between the first electrode and the second electrode. The EL 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, and a second organic compound. The first organic compound is an organic compound including a first pi-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound including a second p-electron-deficient heteroaromatic ring. 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 embodiment of the present invention relates to a light-emitting device.

[0002] Note that one embodiment of the present invention is not limited to the above-mentioned technical field. As an example of the technical field of one embodiment 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-mentioned device can be cited. Background Art

[0003] In recent years, display devices have been used for various purposes. For example, as large-scale display devices, research and development has been carried out for home television devices (also called televisions or television receivers), digital signage, and public information displays (PID: Public Information Display), and as small-scale display devices, research and development has been carried out for smartphones or tablet terminals equipped with touch panels.

[0004] At the same time, the display device is also being made higher-definition. As equipment that requires a high-definition display device, for example, equipment for virtual reality (VR), augmented reality (AR), alternative reality (SR), and mixed reality (MR) is being developed.

[0005] As display elements for display devices, the development of light-emitting devices (also called light-emitting elements) is becoming increasingly popular. Light-emitting devices (also called EL devices, EL elements) that utilize the electroluminescence (hereinafter referred to as EL) phenomenon, especially organic EL devices that mainly use organic compounds, have the following characteristics: they are easy to achieve thinness and lightness; they can respond to input signals at high speed; and they can be driven using a DC constant voltage power supply, etc., so they are preferably used in display devices.

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

[0007] [Patent Document 1] Japanese PCT International Application Translation No. 2018-521459 [Patent Document 2] International Patent Application Publication No. 2021 / 045178 Summary of the invention

[0008] It has been known that the EL layer in an organic EL device (also referred to as a light-emitting device in this specification) is affected in initial characteristics and reliability when exposed to atmospheric components such as water and oxygen, and the EL layer is processed in a near-vacuum atmosphere in a common procedure. In particular, an alkali metal or alkaline earth metal or a compound thereof is used for the electron injection layer, and these metals and compounds are highly reactive with water or oxygen. When the surface of the EL layer is exposed to the atmosphere, the electron injection layer rapidly deteriorates and loses its function as an electron injection layer.

[0009] However, in the process of processing by the above-mentioned photolithography method, the surface of the EL layer has to be exposed to the atmosphere.

[0010] One of the purposes of one embodiment of the present invention is to provide a novel light-emitting device. Another purpose of one embodiment of the present invention is to provide a light-emitting device with good efficiency. Another purpose of one embodiment of the present invention is to provide a light-emitting device with good reliability. Another purpose of one embodiment of the present invention is to provide a light-emitting device with good efficiency and reliability.

[0011] In addition, one of the purposes of one embodiment of the present invention is to provide a novel light-emitting device manufactured through a photolithography process. In addition, one of the purposes of one embodiment of the present invention is to provide a light-emitting device with good efficiency manufactured through a photolithography process. In addition, one of the purposes of one embodiment of the present invention is to provide a light-emitting device with good reliability manufactured through a photolithography process. In addition, one of the purposes of one embodiment of the present invention is to provide a light-emitting device with good luminous efficiency and reliability manufactured through a photolithography process.

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

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

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

[0015] One embodiment of the present invention is a light-emitting device comprising a first electrode, a second electrode and an EL layer. The EL layer is located between the first electrode and the second electrode. The EL layer comprises a light-emitting layer and an electron injection layer. The electron injection layer is a mixed layer comprising a metal or a metal oxide, a first organic compound and a second organic compound. The first organic compound is an organic compound comprising a first π-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound comprising a second π-electron-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 more than 0.20 eV.

[0016] In addition, another embodiment of the present invention is a light-emitting device, which is one of a plurality of light-emitting devices included in a light-emitting device group including a first electrode group formed on the same insulating surface, a second electrode group opposed to the first electrode group, and an EL 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 an EL layer. The first electrode is one of the first electrode groups. The first electrode is independent in each of the plurality of light-emitting devices. The EL layer is one of the EL layer groups. The EL layer is independent in each of the plurality of light-emitting devices. The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The second electrode and the EL layer overlap with the first electrode. The EL layer includes a light-emitting layer and an electron injection layer. The electron injection layer is a mixed layer containing a metal or a metal oxide, a first organic compound, and a second organic compound. The first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound including a second π-electron-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 more than 0.20 eV. The distance between the EL layer in the light-emitting device and the EL layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

[0017] In addition, another embodiment of the present invention is a light-emitting device comprising a first electrode, a second electrode and an EL layer. The EL layer is located between the first electrode and the second electrode. The EL layer comprises a light-emitting layer and an electron injection layer. The electron injection layer has a stacked structure of a first layer comprising a metal and a second layer comprising 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 comprising a first π-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound comprising a second π-electron-deficient heteroaromatic ring. The LUMO energy level of the second organic compound is at least 0.20 eV lower than the LUMO energy level of the first organic compound.

[0018] In addition, another embodiment of the present invention is a light-emitting device, which is one of a plurality of light-emitting devices included in a light-emitting device group including a first electrode group formed on the same insulating surface, a second electrode group opposed to the first electrode group, and an EL 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 an EL layer. The first electrode is one of the first electrode groups. The first electrode is independent in each of the plurality of light-emitting devices. The EL layer is one of the EL layer groups. The EL layer is independent in each of the plurality of light-emitting devices. The second electrode is a continuous conductive layer shared by the plurality of light-emitting devices. The second electrode and the EL layer overlap with the first electrode. The EL layer includes a light-emitting layer and an electron injection layer. The electron injection layer has a stacked structure of a first layer including a metal and a second layer including 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 including a first π-electron-deficient heteroaromatic ring having an electron-donating group. The second organic compound is an organic compound including a second π-electron-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 more than 0.20 eV. The distance between the EL layer of the light-emitting device and the EL layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm to 5 μm.

[0019] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein 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.

[0020] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein 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.

[0021] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is a heteroaromatic ring including two or more pyridine rings.

[0022] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the acidity coefficient pK of the first organic compound is a 8 or above.

[0023] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is different from the second π-electron-deficient heteroaromatic ring.

[0024] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has an azole 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.

[0025] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the acidity coefficient pK of the second organic compound is a Less than 4.

[0026] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the light-emitting layer includes a third organic compound, the third organic compound includes a third π-electron-deficient heteroaromatic ring, and the third π-electron-deficient heteroaromatic ring is the same as the second π-electron-deficient heteroaromatic ring.

[0027] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the light-emitting layer contains a third organic compound, and the third organic compound is the same organic compound as the second organic compound.

[0028] Another embodiment of the present invention is a light-emitting device having the above structure, comprising an electron transport layer between the light-emitting layer and the electron injection layer, wherein the electron transport layer contains a fourth organic compound, and the fourth organic compound is an organic compound different from the third organic compound.

[0029] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the metal is any metal of Group 3, Group 11, and Group 13 of the periodic table.

[0030] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring includes a phenanthroline ring.

[0031] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the first π-electron-deficient heteroaromatic ring is a 1,10-phenanthroline ring having an electron-donating group at at least one of the 4-position and the 7-position.

[0032] In addition, another embodiment of the present invention is a light-emitting device having the above 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.

[0033] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the acidity coefficient pK of the first organic compound is a 8 or above.

[0034] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein when the threshold value of the electron density distribution in the atomic units is 0.0004e / a0 3 The minimum value of the electrostatic potential of the first organic compound is -0.085E h the following.

[0035] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the spin density of the electron injection layer measured by an electron spin resonance method is 5×10 16 spins / cm 3 above.

[0036] In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the electron injection layer is located between the second electrode and the light-emitting layer. In addition, another embodiment of the present invention is a light-emitting device having the above structure, which also includes a hole injection layer, the hole injection layer is located between the first electrode and the light-emitting layer, and the hole injection layer includes a fifth organic compound having a hole transport property and a first substance having an acceptor property for the fifth organic compound. In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the hole injection layer includes a fifth organic compound having a hole transport property and an organic compound including at least four or more of a halogen group and a cyano group. In addition, another embodiment of the present invention is a light-emitting device having the above structure, wherein the hole injection layer includes a fifth organic compound having a hole transport property and an oxide of a metal or metal different from the metal or metal oxide included in the electron injection layer.

[0037] In another embodiment of the light-emitting device of the present invention, the spin density of the hole injection layer measured by electron spin resonance is 1×10 17 spins / cm 3 above.

[0038] In addition, another embodiment of the present invention is a light-emitting device including a plurality of light-emitting devices, wherein the plurality of light-emitting devices are any of the light-emitting devices described above, each of the plurality of light-emitting devices includes an EL layer, the EL layer includes a light-emitting layer and an electron injection layer located between a first electrode and a second electrode, and the EL layer included in each of the plurality of light-emitting devices is independent of each other.

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

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

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

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

[0043] In addition, according to one embodiment of the present invention, a novel light-emitting device that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with good efficiency that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with good reliability that can be used in a high-definition display device can be provided. In addition, according to one embodiment of the present invention, a light-emitting device with good luminous efficiency and reliability that can be used in a high-definition display device can be provided.

[0044] According to one embodiment of the present invention, a highly reliable display device can be provided. According to one embodiment of the present invention, a high-definition display device can be provided. According to one embodiment of the present invention, a high-definition and highly reliable display device can be provided.

[0045] In addition, according to one embodiment of the present invention, a novel organic compound, a novel light-emitting device, a novel display device, a novel display module, and a novel electronic device can be provided.

[0046] Note that the description of these effects does not prevent the existence of other effects. One embodiment of the present invention does not necessarily have all of the above effects. Effects other than the above effects can be extracted from the description of the specification, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1A and Figure 1B 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 is a top view and a cross-sectional view of the light emitting device; FIG. 4A to FIG. 4E is a cross-sectional view showing an example of a method for manufacturing a display device; Figure 5A and Figure 5B is a cross-sectional view showing an example of a method for manufacturing a display device; FIG. 6A to FIG. 6D is a cross-sectional view showing an example of a method for manufacturing a display device; 7A to 7C is a cross-sectional view showing an example of a method for manufacturing a display device; FIG. 8A to FIG. 8C is a cross-sectional view showing an example of a method for manufacturing a display device; 9A to 9C is a cross-sectional view showing an example of a method for manufacturing a display device; Fig. 10A and Fig. 10B is a perspective view showing a structural example of a display module; Fig.11A and Fig. 11B is a cross-sectional view showing a structural example of a display device; Fig.12 is a perspective view showing a structural example of a display device; Fig.13 is a cross-sectional view showing a structural example of a display device; Fig.14 is a cross-sectional view showing a structural example of a display device; Fig.15 is a cross-sectional view showing a structural example of a display device; FIG. 16A to FIG. 16D is a diagram showing an example of an electronic device; FIG. 17A to FIG. 17F is a diagram showing an example of an electronic device; FIG. 18A to FIG. 18G is a diagram showing an example of an electronic device; FIG. 19A to FIG. 19C is the analysis result of the spin density distribution in the ground state of the composite material; Fig. 20A and Fig. 20BIt is the analysis result of the electrostatic potential diagram in the ground state of organic compounds; FIG. 21A to FIG. 21C It is the analysis result of the electrostatic potential diagram of the composite material in the ground state; Fig.22A and Fig. 22B is a diagram showing a light emitting device; FIG. 23A to FIG. 23C is a cross-sectional view showing a structural example of a display device; FIG. 24A to FIG. 24C is a cross-sectional view showing a structural example of a display device; Fig.25 is a diagram showing the brightness-current density characteristics of the light emitting device 1-1, the light emitting device 1-2, and the comparative light emitting device 1; Fig.26 is a diagram showing the brightness-voltage characteristics of the light emitting device 1-1, the light emitting device 1-2, and the comparative light emitting device 1; Fig. 27 is a graph showing current efficiency-current density characteristics of the light emitting device 1-1, the light emitting device 1-2, and the comparative light emitting device 1; Fig.28 is a graph showing current density-voltage characteristics of the light emitting device 1-1, the light emitting device 1-2, and the comparative light emitting device 1; Fig.29 is a diagram showing electric field emission spectra of the light emitting device 1-1, the light emitting device 1-2, and the comparative light emitting device 1; Fig.30 is a graph showing the luminance-current density characteristics of the light emitting device 2-1, the light emitting device 2-2, the comparative light emitting device 2-1, and the comparative light emitting device 2-2; Fig.31 is a diagram showing the brightness-voltage characteristics of the light emitting device 2-1, the light emitting device 2-2, the comparative light emitting device 2-1, and the comparative light emitting device 2-2; Fig.32 is a graph showing current efficiency-current density characteristics of the light emitting device 2-1, the light emitting device 2-2, the comparative light emitting device 2-1, and the comparative light emitting device 2-2; Fig.33 is a graph showing current density-voltage characteristics of the light emitting device 2-1, the light emitting device 2-2, the comparative light emitting device 2-1, and the comparative light emitting device 2-2; Fig.34 is a diagram showing electric field emission spectra of the light emitting device 2-1, the light emitting device 2-2, the comparative light emitting device 2-1, and the comparative light emitting device 2-2; Fig.35 This is a diagram showing the relationship between the LUMO level of the second organic compound and the voltage increase caused by processing using the photolithography method. DETAILED DESCRIPTION

[0048] The embodiments are described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and a person skilled in the art can easily understand that the mode and details can be transformed into various forms without departing from the purpose and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the contents described in the embodiments shown below.

[0049] Note that in this specification, etc., a device manufactured using a metal mask or FMM (Fine Metal Mask) is sometimes referred to as a device having an MM (Metal Mask) structure. In addition, in this specification, etc., a device manufactured without using a metal mask or FMM is sometimes referred to as a device having an MML (Metal Mask Less) structure.

[0050] Implementation Method 1 As one of the methods for forming an organic semiconductor film into a prescribed shape, a vacuum evaporation method (mask evaporation) using a metal mask is widely used. However, with the recent progress in high density and high definition, due to various reasons represented by problems in position alignment accuracy and problems in the configuration interval with the substrate, further high definition of mask evaporation is approaching the limit. On the other hand, it is expected to realize an organic semiconductor device with a denser pattern by processing the shape of the organic semiconductor film using photolithography. Furthermore, photolithography is easier to achieve large area than mask evaporation, so research on processing organic semiconductor films using photolithography is underway.

[0051] On the other hand, it has been known that the EL layer in an organic EL device is affected in initial characteristics or reliability when exposed to atmospheric components such as water and oxygen, and therefore is usually processed in an atmosphere close to a vacuum.

[0052] In particular, the electron injection layer of the light-emitting device mostly uses alkali metals or alkaline earth metals or their compounds (hereinafter also referred to as Li compounds, etc.), but these Li compounds, etc. are very reactive with water or oxygen, and will deteriorate rapidly when exposed to the atmosphere and lose their function as electron injection layers.

[0053] However, in the process of processing by photolithography, the surface of the EL layer is inevitably exposed to the atmosphere. Therefore, when processing by photolithography, the electron injectivity of the electron injection layer using alkali metal compounds etc. is greatly reduced. As a result, the driving voltage of the organic EL device processed by photolithography including the electron injection layer using alkali metal compounds etc. increases, making it difficult to obtain good characteristics.

[0054] Here, the present inventors have found that by using a layer including a metal or a metal oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) as an electron injection layer, an organic EL device with good characteristics can be realized even if a photolithography process that exposes the EL layer to the atmosphere is performed.

[0055] That is, by using a layer including a metal or a metal oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound having a second π-electron-deficient heteroaromatic ring as an electron injection layer, an organic EL device with excellent characteristics can be achieved even if a photolithography process that exposes the EL layer to the atmosphere is performed.

[0056] 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 at least 0.80 eV and at most 0.20 eV, further preferably by at least 0.50 eV and at most 0.20 eV, more preferably by at least 0.50 eV and at most 0.25 eV, more preferably by at least 0.50 eV and at most 0.30 eV, more preferably by at least 0.50 eV and at most 0.35 eV, further preferably by at least 0.50 eV and at most 0.40 eV.

[0057] 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)

[0058] More preferably, LUMO2 satisfies the formula (2). LUMO1-0.50≤LUMO2≤LUMO1-0.20 Formula (2)

[0059] More preferably, LUMO2 satisfies the formula (3). LUMO1-0.50≤LUMO2≤LUMO1-0.25 Formula (3)

[0060] More preferably, LUMO2 satisfies the formula (4). LUMO1-0.50≤LUMO2≤LUMO1-0.30 Formula (4)

[0061] More preferably, LUMO2 satisfies the formula (5). LUMO1-0.50≤LUMO2≤LUMO1-0.35 Formula (5)

[0062] More preferably, LUMO2 satisfies the formula (6). LUMO1-0.50≤LUMO2≤LUMO1-0.40 Formula (6)

[0063] When LUMO2 is within the above range, the light-emitting device of one embodiment of the present invention can realize a light-emitting device with low driving voltage and good characteristics without going through a photolithography step involving exposure of the EL layer to the atmosphere. In addition, a light-emitting device with good reliability can be realized.

[0064] The metal or metal oxide, the first organic compound and the second organic compound form a donor energy level (SOMO energy level or HOMO energy level) by interaction. Thus, the electron injection barrier can be reduced, and the electrons generated in the intermediate layer can be smoothly injected into the electron transport layer, without using the existing electron injection layer that is significantly degraded by the unstable accompanying lithography process exposed to the atmosphere. In addition, when LUMO2 is within the above range, it is possible to interact more stably, and an electron injection layer that is not easily degraded even after the accompanying lithography process exposed to the atmosphere can be formed. Therefore, even after the lithography process exposed to the atmosphere with the EL layer, electrons can be smoothly injected and transferred to the electron transport layer, thereby the rise of the driving voltage can be suppressed and the reliability of the light-emitting device can be used to manufacture the lithography process.

[0065] Note that the HOMO level and LUMO level of an organic compound are generally estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values ​​of different compounds, it is preferable to use values ​​estimated by the same measurement for comparison.

[0066] In this way, by using an organic compound (first organic compound) containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, and a metal or metal oxide as an electron injection layer, an electron injection layer resistant to oxygen and water in the atmosphere and water and chemical solutions used in the photolithography process can be formed. Thus, one embodiment of the present invention can provide a light-emitting device having high moisture resistance, high water resistance, high oxygen resistance, high chemical resistance, low driving voltage, and high luminous efficiency.

[0067] In addition, as a structure of an electron injection layer including an organic compound (first organic compound) containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, an organic compound (second organic compound) containing a second π-electron-deficient heteroaromatic ring, and a metal or metal oxide, a structure of a mixed layer of a metal or metal oxide, a first organic compound, and a second organic compound is preferably used. Alternatively, a laminated structure of a layer containing a metal and a layer containing a first organic compound and a second organic compound may also be used.

[0068] When the electron injection layer adopts a stacked structure of a layer containing a metal and a layer containing a first organic compound and a second organic compound, it is preferably adopted that the layer containing the metal is located on the cathode side, the layer containing the first organic compound and the second organic compound is located on the anode side and is stacked 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.

[0069] When the electron injection layer is a mixed layer of a metal or metal oxide, a first organic compound, and a second organic compound, the number of layers can be reduced compared to a stacked structure, so that productivity is high and mass production is easy.

[0070] Note that when alkali metals or alkaline earth metals and their oxides such as lithium oxide (Li2O) are used for the electron injection layer of the existing structure of the organic EL device, the light-emitting device has good characteristics as long as it is a vacuum continuous process. However, as described above, when the EL layer is exposed to the atmosphere through the photolithography process, even the light-emitting device using alkali metals or alkaline earth metals and their oxides for the electron injection layer has a significantly increased driving voltage compared to the light-emitting device manufactured through the vacuum continuous process. As described above, this is because the alkali metals or alkaline earth metals and their oxides deteriorate when exposed to the atmosphere, resulting in a decrease in their donor properties.

[0071] That is, in another embodiment of the present invention, by using an oxide of an alkali metal or alkaline earth metal such as lithium oxide (Li2O), an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) as an electron injection layer, an organic EL device having the same good characteristics as a light-emitting device manufactured by a vacuum continuous process can be obtained even if the organic EL device is manufactured through a photolithography process accompanied by exposure to the atmosphere.

[0072] This is because, by using an alkali metal or alkaline earth metal and its oxide, a first organic compound containing a first π-electron-deficient heteroaromatic ring having electron-donating properties, and a second organic compound containing a second π-electron-deficient heteroaromatic ring as the electron injection layer, a donor energy level (SOMO energy level or HOMO energy level) is formed due to the interaction, but since the absolute value of the stabilization energy caused by the interaction is large and its energy level is high, the electron injection barrier from the electron injection layer to the electron transport layer is reduced even after exposure to the atmosphere, and the electrons generated in the electron injection layer can be smoothly injected and transported to the electron transport layer. Therefore, even if exposed to the atmosphere, an organic EL light-emitting device with good characteristics can be realized with a suppressed increase in driving voltage.

[0073] In this way, a light-emitting device of one embodiment of the present invention, in which a layer including a metal or metal oxide, an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) is used as an electron injection layer, can realize an organic EL device with good characteristics even after a process of exposing the EL layer to the atmosphere. That is, by using a structure of one embodiment of the present invention, an organic EL light-emitting device with good characteristics manufactured by a photolithography method including a process of exposing the EL layer to the atmosphere can be realized. Thus, a display device with ultra-high definition and good characteristics can be provided.

[0074] <<Electron Injection Layer>> As described above, the electron injection layer is disposed between the cathode and the light-emitting layer, and comprises a metal or metal oxide and an organic compound having a first π-electron-deficient heteroaromatic ring (first organic compound) and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound).

[0075] <Metal or Metal Oxide> As the metal or metal oxide in the electron injection layer, a metal or its oxide 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 including lanthanide elements such as Y, Eu, Yb; Group 11 elements such as Cu, Ag, Au; rare earth metals such as Al, In (Group 13 elements); and Group 14 elements such as Sn.

[0076] In the case where metal or metal oxide preferably uses alkali metal or alkaline earth metal and their 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 transferred to the electron injection layer, thus providing a light-emitting device with low driving voltage and high efficiency. In addition, metal oxide preferably uses transition metal and their oxide, because its reactivity with components such as water and oxygen in the atmosphere is low and relatively stable. In the above-mentioned materials, it is preferred to use a metal or metal oxide containing an element of an odd-numbered group (the 1st group, the 3rd group, the 11th group or the 13th group) belonging to the periodic table of elements, because it is easy to form a donor energy level with the first organic compound and the second organic compound.

[0077] In addition, it is preferred to use a metal or metal oxide that has a low melting point and can be deposited by vacuum evaporation, thereby making it easy to form a mixed layer or stack with an organic compound. Specifically, for example, metals or metal oxides of Group 11 elements and Group 13 elements have a low melting point 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 a metal or metal oxide that can be deposited by vacuum evaporation, its melting point at normal pressure is preferably below 2000°C, below 1500°C, and more preferably below 1000°C, or its sublimation temperature under reduced pressure (vacuum below 1 Pa) is preferably below 1500°C, below 1000°C, and more preferably below 500°C.

[0078] Specific examples of the metal oxide include lithium, magnesium, calcium, silver, indium, and oxides thereof. Note that even metals may be oxidized to become metal oxides during a process such as deposition or release to the atmosphere.

[0079] Specifically, for example, lithium, magnesium, calcium, ytterbium, silver, aluminum, indium, or the like is preferably used as the metal material.

[0080] <First organic compound> As the first organic compound contained in the electron injection layer, an organic compound having a π-electron-deficient heteroaromatic ring can be used. More preferably, an organic compound containing a π-electron-deficient heteroaromatic ring having an electron-donating group is used as the first organic compound, thereby increasing the electron density of the π-electron-deficient heteroaromatic ring.

[0081] In addition, the organic compound having a π-electron-deficient heteroaromatic ring is preferably an organic compound having a heteroaromatic ring containing nitrogen, and the heteroaromatic ring containing nitrogen is preferably a pyridine ring, and particularly preferably an organic compound having a heteroaromatic ring containing two or more pyridine rings. This is because the two nitrogen atoms contained in the organic compound having a heteroaromatic ring containing two or more pyridine rings are coordinated to the metal or metal oxide, and are easy to interact with the metal or metal oxide.

[0082] In organic compounds having heteroaromatic rings containing two or more pyridine rings, nitrogen atoms are more easily coordinated to metals or metal oxides in organic compounds having bipyridine skeletons, and therefore are easily interacted with metals or metal oxides, so they are preferred. In addition, the phenanthroline ring is rigid and stable, so it is preferred. Among them, in particular, the two nitrogen atoms contained in the organic compound having 1,10-phenanthroline ring are present in a position that is easily coordinated to metals or metal oxides, so they are easily interacted with metals or metal oxides, so they are preferred.

[0083] When an electron-donating group is introduced into the 1,10-phenanthroline ring, the electron-donating group is preferably substituted at positions 4 and 7 of the 1,10-phenanthroline ring. By introducing electron-donating groups at positions 4 and 7 of the 1,10-phenanthroline ring, the electron density of the nitrogen atoms at positions 1 and 10 can be increased, thereby facilitating interaction with metals or metal oxides.

[0084] As the electron-donating group in the π-deficient heteroaromatic ring, alkyl, alkoxy, aryloxy, alkylamino, arylamino, heterocyclic amino, etc. can be cited. However, the electron-donating group preferably introduced on the π-deficient heteroaromatic ring is not limited thereto. As long as it is a base that can increase the electron density of the π-deficient heteroaromatic ring by introducing it on the π-deficient heteroaromatic ring, it can be used as an electron-donating group. In addition, the electron-donating group can also 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.

[0085] Specific examples of the alkyl group that can be used as the electron-donating group include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, isobutyl, tert-butyl, pentyl, isopentyl, sec-pentyl, tert-pentyl, neopentyl, hexyl, isohexyl, sec-hexyl, tert-hexyl, neohexyl, 3-methylpentyl, 2-methylpentyl, 2-ethylbutyl, 1,2-dimethylbutyl and 2,3-dimethylbutyl.

[0086] Specific examples of the alkoxy group that can be used as the above-mentioned electron-donating group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy, tert-butoxy, n-pentoxy, isopentoxy, sec-pentoxy, tert-pentoxy, neopentoxy, n-hexoxy, isohexoxy, sec-hexoxy, tert-hexoxy, and neohexyloxy.

[0087] Specific examples of the aryloxy group that can be used as the electron-donating group include phenoxy, o-tolyloxy, m-tolyloxy, p-tolyloxy, mesityloxy, o-biphenyloxy, m-biphenyloxy, p-biphenyloxy, 1-naphthyloxy, 2-naphthyloxy, 2-fluorenyloxy, etc. The aryloxy group may further have a substituent, and specific examples of the substituent include alkyl, alkoxy, phenyl, etc.

[0088] Specific examples of the alkylamino group which can be used as the electron-donating group include a dimethylamino group and a diethylamino group.

[0089] Specific examples of the arylamino group that can be used as the electron-donating group include diphenylamino, bis(α-naphthyl)amino, bis(m-tolyl)amino, etc. The arylamino group may further have a substituent, and specific examples of the substituent include alkyl, alkoxy, phenyl, etc.

[0090] Specific examples of the heterocyclic amino group that can be used as the electron-donating group include groups represented by the following structural formulas (R-1) to (R-26). Note that the heterocyclic amino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, and the like.

[0091] [Chemical formula 1]

[0092] In addition, the group represented by the structural formula (R-1), (R-2), (R-3), (R-4), (R-5), (R-8), (R-9), (R-10), (R-12), (R-14), (R-15), (R-16), (R-17) or (R-21) is more preferred as an electron-donating group. Among them, the group represented by the structural formula (R-3) (R-4) (R-8) or (R-21) has high electron-donating properties and can further increase the electron density of the phenanthroline ring, so it is particularly preferred.

[0093] Specific examples of the electron-donating group include groups represented by the following structural formulas (R-27) and (R-28).

[0094] [Chemical formula 2]

[0095] Note that the organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound can also have both the above-mentioned electron-donating group and a substituent other than the above-mentioned group. As a specific example of a substituent other than the above-mentioned electron-donating group that can be introduced into the π-electron-deficient heteroaromatic ring, an aryl group can also be cited. As a specific example of an aryl group, phenyl, o-tolyl, m-tolyl, p-tolyl, mesityl, o-biphenyl, m-biphenyl, p-biphenyl, 1-naphthyl, 2-naphthyl, 2-fluorenyl, etc. can be cited. The aryl group can also have a substituent, and as a specific example of the substituent, an alkyl group, an alkoxy group, a phenyl group, etc. can be cited.

[0096] Structural formulae (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 compound that can be used as the first organic compound is not limited thereto.

[0097] [Chemical formula 3]

[0098] 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 absolute value of the stabilization energy due to the interaction with the metal or the metal oxide is large, which is preferable.

[0099] In organic compounds having π-electron-deficient heteroaromatic rings, the electrostatic potential around the heteroatoms of the π-electron-deficient heteroaromatic rings tends to become negative. By introducing electron-donating groups into the π-electron-deficient heteroaromatic rings, the electrostatic potential around the heteroatoms of the π-electron-deficient heteroaromatic rings can be further reduced (the absolute value of the negative value can be increased).

[0100] Electrostatic potential refers to the interaction energy between a positive point charge with a unit charge and the electron distribution of a molecule. In addition, the value of electrostatic potential also varies depending on the threshold value of electron density.

[0101] In order to improve the efficiency of interaction with the metal or metal oxide, the minimum value of the electrostatic potential of the first organic compound is preferably smaller than (greater in a negative direction than) the minimum value of the electrostatic potential of a π-electron-deficient heteroaromatic ring having no substituent.

[0102] Specifically, when the threshold of the electron density distribution in the atomic unit system is 0.0004e / a0 3 (e represents 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 hrepresents the Hartree energy (1E h =27.211eV)) or less, preferably -0.090E h In addition, when the threshold of electron density distribution is 0.003e / a0 3 When the minimum value of the electrostatic potential of the first organic compound is preferably -0.12E h Below, more preferably -0.13E h In addition, when the threshold of electron density distribution is 0.0004e / a0 3 When the minimum value of ESP of the first organic compound is preferably -0.085E h Below, it is more preferred that when the threshold value of the electron density distribution is 0.003e / a0 3 The minimum value is -0.12E h .

[0103] The minimum values ​​of the electrostatic potential (ESP) of the organic compounds represented by the above-mentioned structural formulas (100) to (107), the organic compounds represented by the structural formula (111), BPhen, mPPhen2P, NBPhen, and Phen, which can be used as the first organic compound, were estimated by quantum chemical calculation. The structural formulas of the organic compounds represented by the structural formulas (100) to (107), the organic compounds represented by the structural formula (111), BPhen, mPPhen2P, NBPhen, and Phen are shown below.

[0104] [Chemical formula 4]

[0105] Gaussian09 was used as a quantum chemical calculation program. SGI8600 manufactured by HPE was used for calculation. The most stable structure of each organic compound in the ground state was calculated using density functional theory (DFT). 6-311G (d, p) was used as the basis function, and B3LYP was used as the functional.

[0106] Table 1 shows the analysis results of the electrostatic potential in the ground state of each organic compound. Note that the electrostatic potential refers to the interaction energy between a positive point charge with a unit charge and the electron distribution of a molecule. In addition, the value of the electrostatic potential also varies according to the threshold value of the electron density. Table 1 shows the analysis results when the density threshold in the atomic unit system is 0.0004e / a. 3 or 0.003e / a0 3 The electrostatic potential in the electron density distribution when .

[0107] [Table 1]

[0108] From the table above, we can see that when the threshold of electron density distribution in the atomic unit system is 0.0004e / a0 3 When , the minimum ESP of the organic compounds represented by the structural formula (100) to the structural formula (103) and the structural formula (111) is -0.085E h In addition, when the threshold value of the electron density distribution in the atomic unit system is 0.003e / a0 3 When , the minimum ESP of the organic compounds represented by the structural formula (100) to the structural formula (103) and the structural formula (111) is -0.12E h The following are more preferably used as the first organic compound.

[0109] This is because the organic compounds represented by Structural Formulas (100) to (103) and (111) have electron-donating groups introduced at the 4- and 7-positions of the 1,10-phenanthroline ring, thereby providing high electron-donating properties to nitrogen at the 1- and 10-positions of the phenanthroline ring.

[0110] In addition, when the threshold of the electron density distribution in the atomic unit system is 0.0004e / a0 3 When , the minimum ESP of the organic compounds represented by the structural formula (100), the structural formula (103) and the structural formula (111) is -0.090E h In addition, when the threshold value of the electron density distribution in the atomic unit system is 0.003e / a0 3 When the organic compounds represented by the structural formula (103) and the structural formula (111) have a minimum ESP of -0.13E h The following are particularly suitable for use as the first organic compound.

[0111] In addition, when the threshold of the electron density distribution in the atomic unit system is 0.0004e / a0 3 When the organic compounds represented by the structural formula (103) and the structural formula (111) have a minimum ESP of -0.090E h Below and when the threshold value of the electron density distribution in the atomic unit system is 0.003e / a0 3 The minimum ESP value is -0.13E h The following is further preferably used as the first organic compound.

[0112] In addition, when the basicity of the first organic compound is high, the hole transport property in the electron injection layer can be greatly reduced through interaction with holes, thereby realizing a light-emitting device with high efficiency and low driving voltage, which is preferred. Specifically, the acidity coefficient pK of the first organic compound is aIt is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

[0113] In addition, the acidity coefficient pK of organic compounds a If unknown, investigate the acidity coefficient pK of each skeleton of the organic compound. a , the largest acidity coefficient pK a Considered as the acidity coefficient pK of the organic compound a .

[0114] Alternatively, the acidity coefficient can be calculated. For example, the acidity coefficient pK can be calculated using the following calculation method: a .

[0115] As the initial structure of the molecular structure of each molecule used as the calculation model, the most stable structure (single ground state) obtained by first-principles calculation was adopted.

[0116] As in the above first principles calculation, use Jaguar, a quantum chemical calculation software manufactured by Inc., calculates 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 function. As the structure for quantum chemical calculation, Maestro GUI manufactured by , Inc., performs conformational analysis and sampling using Mixed torsional / Low-mode sampling.

[0117] In pK a In the calculation, one or more atoms in each molecule were designated as basic positions, and the Macro Model was used to explore the stable structure of the protonated molecule in water. The conformer with the lowest energy obtained by conformational exploration using the OPLS2005 force field was used. The pK values ​​of Jaguar were used. a The calculation module uses B3LYP / 6-31G* to optimize the structure, and then performs single-point calculations with cc-pVTZ(+) to calculate the pK using empirical corrections for functional groups. a In molecules where more than one atom is assigned as a basic site, the largest value obtained is used as the pK a The obtained pK a The value of .

[0118] 2,9hpp2Phen acidity coefficient pK a The acidity coefficient pK is 13.35, 4, 7 hpp2Phen a The acidity coefficient pK of Pyrrd-Phen is 13.42. aThe acidity coefficient pK of mPPhen2P is 11.23. a The acidity coefficient pK of NBPhen is 5.16. a The acidity coefficient pK of BPhen is 5.59. a It is 5.62.

[0119] <Estimating the Interaction between Metals and Organic Compounds Using Quantum Chemical Calculations> Here, the spin density and electrostatic potential (ESP) when a metal interacts with a first organic compound including a π-electron-deficient heteroaromatic ring having an electron-donating group and a second organic compound having a π-electron-deficient heteroaromatic ring are analyzed by quantum chemical calculation. Note that the calculation was performed using 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) 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) as the second organic compound, and silver (Ag) as the metal.

[0120] As a quantum chemical calculation program, Gaussian09 is used. SGI8600 manufactured by HPE is used for calculation. Density functional theory (DFT: Density Functional Theory) is used to calculate the most stable structure of the first organic compound monomer and the second organic compound monomer in the ground state, 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 of 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 are used as basis functions, and B3LYP is used as a functional. The total energy of DFT is expressed as the sum of potential energy, electrostatic energy between electrons, kinetic energy of electrons, and exchange-correlation energy including all complex interactions between electrons. In DFT, since the exchange-correlation interaction is approximated using a functional (meaning a function of a function) of a single electron potential represented by electron density, the calculation accuracy is high.

[0121] Fig.19A and Fig.19BThe 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 balls in the figure represent the atoms constituting the compound, and the clouds around the atoms represent that the threshold value of the electron density distribution in the atomic unit system is 0.003e / a. 3 The spin density distribution at the time of , and indicates that the doublet ground state in the compound is localized. Note that since the ground state of the first organic compound (Pyrrd-Phen) and the ground state of the second organic compound (11mDBtBPPnfpr) are singlet ground states, no spin density distribution is observed.

[0122] When the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag) is in a double ground state, the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atoms (nitrogen atoms (N) at the 1st and 10th positions) having non-shared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) to become stable, thereby forming a composite material. Fig.19A It can be seen that part of the spins derived from the unpaired electrons of the metal (Ag) are distributed on a part of the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), especially on the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs. However, since the interaction is weak, most of the spins are distributed on the metal (Ag).

[0123] In addition, when the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double ground state, the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. Thus, according to Fig.19B It is known that part of the spins derived from the unpaired electrons of the metal (Ag) are distributed on a part of the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), especially on the nitrogen atom (N) having an unshared electron pair. However, since the interaction is weak, most of the spins are distributed on the metal (Ag).

[0124] On the other hand, in one embodiment of the present invention, when the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double 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 atom (nitrogen atom (N) at the 1st and 10th positions) having a non-shared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. Thus, according to Fig.19C It can be seen that the spins of the unpaired electrons contained in the metal (Ag) are locally distributed on the second organic compound (11mDBtBPPnfpr). In addition, the spin density distribution of the metal (Ag) is not observed. It can be seen 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 a radical anion state.

[0125] then, Fig. 20A , Fig. 20B , Fig.21A , Fig. 21B and Fig. 21C The analysis results of the electrostatic potential diagram 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 metal (Ag), the composite material of the second organic compound (11mDBtBPPnfpr) and metal (Ag), and the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and metal (Ag) are shown. The balls in the figure represent the atoms constituting the compound, and the clouds around the atoms represent that the threshold value of the electron density distribution in the atomic unit system is 0.0004e / a. 3 Electrostatic potential in the electron density distribution when . Electrostatic potential is the interaction energy between a positive point charge with unit charge and the electron distribution of a molecule. Electrostatic potential maps use colors to represent the electrostatic potential in the equal electron density surface. In the electrostatic potential map, red and blue are used to represent areas with negative and positive electrostatic potential, respectively. Atoms in areas with negative electrostatic potential have negative charges, and atoms in areas with positive electrostatic potential have positive charges. Note that due to Fig. 20A and Fig. 20B as well as FIG. 21A to FIG. 21C It is a grayscale image, so in order to indicate the area with negative electrostatic potential and the area with positive electrostatic potential, the part represented by dark red (i.e., the area with negative electrostatic potential) is surrounded by a thick dotted line, and the part represented by dark blue (i.e., the area with positive electrostatic potential) is surrounded by a thin dotted line.

[0126] like Fig. 20A As shown, it can be seen that in the singlet ground state of the first organic compound (Pyrrd-Phen), the electrostatic potential around the nitrogen atom (nitrogen atom (N) at position 1 and position 10) having a non-shared electron pair in the 1,10-phenanthroline ring is negative. In addition, the Mulliken partial charge of the N atom is a negative value in the atomic unit system, specifically -0.29e. Therefore, it can be seen that the N atom has a negative partial charge.

[0127] like Fig. 20B As shown, it can be seen that in the singlet ground state of the second organic compound (11mDBtBPPnfpr), the electrostatic potential around the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring is negative. In addition, the Mulliken partial charge of the N atom is negative in the atomic unit system, specifically -0.31e. Therefore, it can be seen that the N atom has a negative partial charge.

[0128] When the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag) is in a double ground state, the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atoms (nitrogen atoms (N) at the 1st and 10th positions) having non-shared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) to become stable, thereby forming a composite material. As a result, Fig.21A As shown, it can be seen that the electrostatic potential around the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) and the metal (Ag) in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) is negative. In addition, the Mulliken partial charge of each N atom is negative in the atomic unit system, specifically -0.37e, and the Mulliken partial charge of the metal (Ag) is negative in the atomic unit system, specifically -0.18e. It can be seen that the N atom and the Ag atom have negative partial charges.

[0129] When the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double ground state, the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) coordinates to the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. As a result, as Fig. 21B As shown, it can be seen that the electrostatic potential around the nitrogen atom (N) and the metal (Ag) having a non-shared electron pair in the phenanthro[9', 10': 4, 5] furano[2, 3-b] pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative. In addition, the Mulliken partial charge of each N atom is a negative value in the atomic unit system, specifically -0.38e, and the Mulliken partial charge of the metal (Ag) is a negative value in the atomic unit system, specifically -0.09e. Therefore, it can be seen that the N atom and the Ag atom have negative partial charges.

[0130] On the other hand, in one embodiment of the present invention, when the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is in a double 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 atom (nitrogen atom (N) at the 1st and 10th positions) having a non-shared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to become stable, thereby forming a composite material. As a result, as Fig. 21C As 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 around the nitrogen atom (N) with a non-shared electron pair in the phenanthro[9',10':4,5]furano[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative, while the electrostatic potential around the metal (Ag) is positive. In addition, the Mulliken partial charge of the N atom is a negative value in the atomic unit system, specifically -0.62e, while the Mulliken partial charge of the metal (Ag) is a positive value in the atomic unit system, specifically 0.37e. It can be seen that the charge of the Ag atom is distributed on the N atom.

[0131] It can be seen that the following combination is formed: a donor energy level is formed by the interaction between the first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring and the metal, and the second organic compound having a π-electron-deficient heteroaromatic ring acts as an electron donor. In one embodiment of the present invention, by using a material having this combination for an electron injection layer, an electron injection layer having good electron injection properties and resistance to oxygen and water in the atmosphere and water and chemical solutions used in the process in lithography can be formed, thereby realizing a light-emitting device with reduced driving voltage and high luminous efficiency.

[0132] <Estimation of SOMO or HOMO energy levels in the interaction between metals and organic compounds using quantum chemical calculations> Next, quantum chemical calculations are used to estimate the stability energy and the SOMO energy level or HOMO energy level formed when the metal interacts with the first organic compound containing a π-electron-deficient heteroaromatic ring having an electron-donating group and the second organic compound containing a π-electron-deficient heteroaromatic ring.

[0133] As a quantum chemical calculation program, Gaussian09 is used. SGI8600 manufactured by HPE is used for calculation. First, the most stable structures of the first organic compound, the second organic compound and the metal in the ground state, as well as the composite material of the first organic compound and the metal, the composite material of 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 are calculated using density functional theory (DFT). 6-311G (d, p) and LanL2DZ are used as basis functions, and B3LYP is used as a functional. Next, the total energy of the composite material of the organic compound and the metal is subtracted from the sum of the total energy of the organic compound monomer and the total energy of the metal monomer to calculate the stability energy. That is, (stable 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).

[0134] The following table shows that 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as Pyrrd-Phen) is the first organic compound, 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), 9-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9mDBtBPNfpr), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofuran The results are calculated using indium (In) as the metal, and using 2-[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), and 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) as the second organic compound. Note that the HOMO and SOMO energy levels in the table are calculated values ​​and may differ from the actual measured values.

[0135] [Table 2]

[0136] [Table 3]

[0137] [Table 4]

[0138] As can be seen from the above table, the stability energy of the composite material of the two materials of the metal (In) and the second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) is negative. This means that when the organic compound and the metal are mixed, the interaction between them is more stable in energy than the case where the organic compound and the metal do not interact. In addition, the SOMO energy level formed at this time is higher than the HOMO energy level of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn).

[0139] In addition, compared with the composite material of a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-electron-deficient heteroaromatic ring different from the 1,10-phenanthroline ring and a metal (In), the absolute value of the stabilization energy of the composite material of a second organic compound (NBPhen) having a π-electron-deficient heteroaromatic ring that is the same as the Pyrrd-Phen of the first organic compound and a metal (In) is larger and more stabilized, and the formed SOMO energy level is also higher.

[0140] Here, compared with the composite material of two materials consisting of a metal (In) and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), the composite material of three materials consisting of a metal (In), a first organic compound (Pyrrd-Phen) and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) according to one embodiment of the present invention has a larger absolute value of stabilization energy and is more stabilized. In addition, the SOMO energy level formed at this time is higher than the HOMO energy level of each of the first organic compound (Pyrrd-Phen) and the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn). The higher the SOMO energy level, the better the electron injection property, so it is preferred.

[0141] At this time, compared with the composite material of the second organic compound (NBPhen) having the same 1,10-phenanthroline ring as Pyrrd-Phen as a π-electron-deficient heteroaromatic ring, the first organic compound (Pyrrd-Phen) and the metal (In), the composite material of the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn) having a π-electron-deficient heteroaromatic ring different from the 1,10-phenanthroline ring contained in Pyrrd-Phen of the first organic compound, the first organic compound (Pyrrd-Phen) and the metal (In) has a large absolute value of the stabilization energy and is stabilized, and the formed SOMO energy level is also higher.

[0142] In this way, when an organic compound comprising a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound), an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) and a metal interact to form a composite material, the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are preferably different rings, thereby improving stability and electron injection properties.

[0143] In addition, as shown in the above table, the absolute value of the stability energy of the composite material of the metal, the first organic compound and the second organic compound is large and more stabilized, so it is preferred. In addition, the SOMO energy level formed at this time is higher than the HOMO energy level of the first organic compound and the second organic compound. The higher the SOMO energy level, the better the electron injection property, so it is preferred. In addition, due to the use of metals such as silver or indium that are stable in the atmosphere without using alkali metal compounds, a high SOMO energy level is also formed, so an electron injection layer with excellent stability and electron injection property can be formed.

[0144] <Second organic compound> The electron injection layer further comprises a second organic compound having a π-electron-deficient heteroaromatic ring in addition to the metal or metal oxide and the first organic compound. By including the second organic compound, it is possible to achieve improved heat resistance and improved electron transport properties. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring possessed by the first organic compound is a first π-electron-deficient heteroaromatic ring and the π-electron-deficient heteroaromatic ring possessed by the second organic compound is a second π-electron-deficient heteroaromatic ring, the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are preferably different rings.

[0145] In addition, the second π-electron-deficient heteroaromatic ring is preferably a heteroaromatic ring having an azole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton and a heteroaromatic ring having a triazine skeleton, etc., and is particularly preferably a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring), or a triazine ring, which is electrochemically stable and has high electron transport properties.

[0146] Note that the second π-electron-deficient heteroaromatic ring may have a condensed ring structure.

[0147] 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 at least 0.80 eV and at most 0.20 eV, further preferably by at least 0.50 eV and at most 0.20 eV, more preferably by at least 0.50 eV and at most 0.25 eV, more preferably by at least 0.50 eV and at most 0.30 eV, more preferably by at least 0.50 eV and at most 0.35 eV, further preferably by at least 0.50 eV and at most 0.40 eV.

[0148] 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)

[0149] More preferably, LUMO2 satisfies the formula (2). LUMO1-0.50≤LUMO2≤LUMO1-0.20 Formula (2)

[0150] More preferably, LUMO2 satisfies the formula (3). LUMO1-0.50≤LUMO2≤LUMO1-0.25 Formula (3)

[0151] More preferably, LUMO2 satisfies the formula (4). LUMO1-0.50≤LUMO2≤LUMO1-0.30 Formula (4)

[0152] More preferably, LUMO2 satisfies the formula (5). LUMO1-0.50≤LUMO2≤LUMO1-0.35 Formula (5)

[0153] More preferably, LUMO2 satisfies the formula (6). LUMO1-0.50≤LUMO2≤LUMO1-0.40 Formula (6)

[0154] When LUMO2 is within the above range, the light-emitting device of one embodiment of the present invention can realize a light-emitting device with low driving voltage and good characteristics without going through a photolithography step involving exposure of the EL layer to the atmosphere. In addition, a light-emitting device with good reliability can be realized.

[0155] As the second organic compound, an organic compound having an electron transport property can be used. As the organic compound having an electron transport property, it is preferable to use an organic compound having an electron mobility of 1×10 - 7 cm 2 / Vs or more, it is more preferable to use the material having an electron mobility of 1×10 -6 cm 2 In addition, any substance other than the above may be used as long as it has a higher electron-transporting property than a hole-transporting property.

[0156] Specific examples of organic compounds having electron transport properties include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2′,2″-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-( 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), 4,7-diphenyl-2,9-bis[4-(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl]-1,10-phenanthroline (abbreviation: DBimiBphen), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq- II), 2-[3′-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mDBTBPDBq-II), 2-[3′-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mCzBPDBq), 2-[4′-(9-phenyl-9H-carbazole-3-yl)-3,1′-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mpPCBPDBq), 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq), 2-[4-(3,6-diphenyl 1-(4-(dibenzothiophene-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3′-(dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[(3′-dibenzothiophene-4-yl)biphenyl-4-yl]naphtho[1′,2′:4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[(3′-dibenzothiophene-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-(dibenzothiophene-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-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-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3′-(dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1′,2′:4,5]furano[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2′-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]phenyl pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2′-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2′-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4 NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviated as PC-cgDBCzQz), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm), 11-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furano[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), an organic compound having a diazine skeleton such as 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), -phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9′-phenyl-2,3′-bi-9H-carbazole (abbreviated as mPCCzPTzn-02), 2-[3′-(9,9-dimethyl-9H-fluorene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviated as m mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: mDBtBPTzn), 2,4,6-tris[3′-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenylindole[2,3-a] Carbazole (abbreviated as BP-Icz(II)Tzn), 2-[3′-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1′:4′,1″-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,Organic compounds having a triazine skeleton, such as 9'-[9H]oxanthene]-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).

[0157] Among the above materials, ZADN, mSiTrz, mPn-mDMePyPTzn, 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr, and βNP-SFx(4)Tzn have suitable LUMO energy levels and are therefore preferred as the second organic compound. By using this organic compound, even a light-emitting device obtained after a process in which the EL layer is exposed to the atmosphere can easily obtain a light-emitting device with good characteristics of suppressing the increase in driving voltage.

[0158] The second organic compound preferably has a carbon number of 25 to 100. By adopting such a carbon number, an organic compound with good sublimation properties can be realized, thereby suppressing thermal decomposition of the organic compound during vacuum deposition, and achieving good material utilization efficiency.

[0159] The second organic compound preferably has a glass transition temperature Tg of 100° C. or higher. This allows the electron injection layer to have high heat resistance and not be easily crystallized. This prevents the EL layer from being easily crystallized even when part of the EL layer is processed by photolithography.

[0160] In addition, as the second organic compound, the acidity coefficient pK a An organic compound having a molecular weight of less than 4. Thus, the solubility of the second organic compound in water can be reduced, thereby improving the resistance to water and chemical solutions used in the process in the lithography technology.

[0161] and acidity coefficient pK a The acidity coefficient pK of organic compounds with a solubility in water of 4 or more is compared a Organic compounds with a pH value less than 4 have low solubility in water. a Compared with the case where an organic compound with a pK value of 4 or more is used as the second organic compound, when the acidity coefficient pK a When an organic compound with a molecular weight of 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 the electron injection layer peeling off from other layers during the manufacturing process can be suppressed. Thus, the occurrence of defects that cause defects in the light-emitting device can be suppressed.

[0162] 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.

[0163] Note that the acidity coefficient pK of 4,8mDBtP2Bfpm a The acidity coefficient pK of 11mDBtBPPnfpr is 0.60. a is -1.85. In addition, the acidity coefficient pK of organic compounds a If unknown, investigate the acidity coefficient pK of each skeleton of the organic compound. a , the largest acidity coefficient pK a Considered as the acidity coefficient pK of the organic compound a .

[0164] In addition, for example, the polarization term δp of the solubility parameter δ can be 4.0 MPa 0.5 The following organic compounds are used as the second organic compound. For example, the polarization term δp with the solubility parameter δ is greater than 4.0 MPa 0.5 Compared with the solubility of organic compounds in water, the polarization term δp is 4.0MPa 0.5 The following organic compounds have low solubility in water. In addition, the polarization term δp is greater than 4.0 MPa. 0.5 Compared with the case where an organic compound of is used as the second organic compound, when the polarization term δp is 4.0 MPa 0.5 When the following organic compounds are used as the second organic compound, the water resistance of the electron injection layer can be improved. In addition, the occurrence of defects such as the electron injection layer peeling off from other layers during the photolithography process can be suppressed. Thus, the occurrence of defects that cause defects in the light-emitting device can be suppressed.

[0165] Japanese Patent Application Publication No. 2017-173056 states that the polarization term δp of the solubility parameter δ of water is 16.0 MPa. 0.5 .

[0166] The larger the difference between the polarization term δp of the solubility parameter δ of the organic compound and the polarization term δp of water as a solvent, the lower its solubility in water is, so it is preferred. Therefore, it is preferred to have a solubility parameter δ of 4.0 MPa. 0.5 The following organic compound having a polarization term δp is used for the second organic compound.

[0167] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn may be used for the second organic compound.

[0168] Note that the polarization term δp of the solubility parameter δ of 8BP-4mDBtPBfpm is 3.5 MPa 0.5 , the polarization term δp of the solubility parameter δ of 4,8mDBtP2Bfpm is 3.4MPa 0.5 , the polarization term δp of the solubility parameter δ of 6BP-4Cz2PPm is 3.4MPa 0.5 , the polarization term δp of the solubility parameter δ of 2mDBTBPDBq-II is 3.2MPa 0.5 , the polarization term δp of the solubility parameter δ of 9mDBtBPNfpr is 3.8MPa 0.5 , the polarization term δp of the solubility parameter δ of 11mDBtBPPnfpr is 3.1MPa 0.5 , the polarization term δp of the solubility parameter δ of mPCCzPTzn-02 is 3.5MPa 0.5 , the polarization term δp of the solubility parameter δ of BP-BPIcz(II)Tzn is 3.2MPa 0.5 .

[0169] Note that the polarization term δp of the solubility parameter δ is calculated by referring to the following calculation method.

[0170] Used as a classical molecular dynamics calculation software Desmond manufactured by Inc. In addition, OPLS2005 force field was used. The calculation was performed using Apollo6500 manufactured by Hewlett Packard Enterprise (HPE).

[0171] As a calculation model, a standard unit with about 32 molecules is used. As the initial structure of the molecular structure in each compound, the most stable structure (single ground state) obtained by first-principles calculation and the structure with the energy of the approximate most stable structure are mixed at the same ratio, and the molecules are irregularly configured in a way that the molecules do not collide. Then, the structure is irregularly migrated and rotated by using the Monte Carlo simulated annealing of OPLS2005 as a force field, thereby migrating the molecules. Furthermore, the molecules are migrated to the center of the standard unit in a way that maximizes their density, which is used as the initial configuration.

[0172] As the first principle calculation, the quantum chemical calculation software Jaguar was used to calculate the most stable structure in the single ground state by density functional theory (DFT). 6-31G** was used as the basis function and B3LYP-D3 was used as the functional function. Sampling was performed by performing conformational analysis using Mixedtorsional / Low-mode sampling using Maestro GUI manufactured by Inc. Calculations were performed using Apollo 6500 manufactured by Hewlett Packard Enterprise (HPE).

[0173] The above initial configuration is subjected to Brownian motion simulation, followed by NVT ensemble, and then NPT ensemble calculation is performed at 1 atm and 300 K with a relaxation time (30 ns) sufficiently longer than the time interval (2 fs) for reproducing molecular vibrations, thereby calculating the amorphous solid. The solubility parameter δ of the obtained amorphous solid is defined by the following formula.

[0174] [Formula 1]

[0175] Here, ΔHv represents the heat of vaporization, which is the value obtained by subtracting the total energy of each molecule averaged in the 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 tends to decrease as the difference between the substance used as the solvent and the substance used as the solute increases.

[0176] In addition, the solubility parameter δ can be divided into a diffusion term δd and a polarization term δp. The van der Waals interaction has an influence on the diffusion term δd, and the electrostatic interaction has an influence on the polarization term δp. In particular, the electrostatic interaction generated between the dipoles of the solute and the water molecule has a great influence on the solubility of the solute in water. In fact, the solubility in water of the organic compound that can be used as the second organic compound shows a good correlation with the polarization term δp of the solubility parameter δ obtained by calculation.

[0177] Note that the LUMO energy level of the second organic compound is preferably lower than the LUMO energy level of the first organic compound. Thus, electrons can be easily supplied to the second organic compound from the donor energy level formed by the first organic compound and the metal or metal oxide. 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.

[0178] The LUMO level of the second organic compound is preferably -3.0 eV to -2.0 eV, more preferably -3.0 eV to -2.5 eV. The LUMO level of the first organic compound is preferably -3.0 eV to -2.0 eV, more preferably -2.7 eV to -2.0 eV.

[0179] This makes it easy to supply electrons from the donor level formed by the first organic compound and the metal or metal oxide to the second organic compound. Also, this makes it easy to transfer electrons in the second organic compound.

[0180] Furthermore, the electron injection layer contains the second organic compound in addition to the metal or metal oxide and the first organic compound, thereby allowing efficient interaction between the materials. This can be confirmed by measuring the spin density using the electron spin resonance method (ESR).

[0181] For example, the spin density measured by ESR of a film comprising a metal or metal oxide and a first organic compound is preferably higher than the spin density measured by ESR of a film comprising a metal or metal oxide and a second organic compound. In addition, the spin density measured by ESR of a film comprising a metal or metal oxide, a first organic compound, and a second organic compound is preferably higher than the spin density measured by ESR of a film comprising any two materials of the metal or metal oxide, the first organic compound, and the second organic compound, in which case it can be confirmed that the materials efficiently interact with each other.

[0182] More specifically, in the film containing the metal or metal oxide and the first organic compound, for example, the spin density of the signal observed at a g value of about 2.00 by the electron spin resonance method is preferably 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3 In this case, it can be confirmed that the materials in the layer containing the metal or metal oxide and the first organic compound interact efficiently. Alternatively, in the film containing the metal or metal oxide, the first organic compound and the second organic compound, for example, the spin density of the signal observed at a g value of 2.00 by the electron spin resonance method is preferably 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3In this case, it can be confirmed that the layer containing the metal or metal oxide, the first organic compound and the second organic compound interacts more efficiently than 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 of the signal observed by the electron spin resonance method at a g value of 2.00 is 2×10 16 spins / cm 3 Next, in a mixed film containing the first organic compound and the second organic compound, for example, the spin density due to a signal observed at a g value of 2.00 by the electron spin resonance method is 2×10 16 spins / cm 3 the following.

[0183] 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 further 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 further 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 with good electron injection can be provided. In addition, the second organic compound may not be used, but in the case of using the second organic compound, 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 further 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 with good electron transport can be provided. In addition, by using an organic compound with good thermal properties of high Tg as the second organic compound, a highly reliable organic EL device can be provided.

[0184] 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 adopts a laminated structure of a metal layer and a layer comprising a 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 adopts a laminated structure of a metal layer and a layer comprising a first organic compound, the thickness of the layer comprising 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.

[0185] The light-emitting device of one embodiment of the present invention having the above-described structure can have excellent characteristics even if it is exposed to the atmosphere before the second electrode is formed or is processed by photolithography involving exposure to the atmosphere.

[0186] Furthermore, the light-emitting device of one embodiment of the present invention having the above-described structure can be a light-emitting device with high current efficiency and high reliability in which an increase in driving voltage is suppressed.

[0187] 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, the light-emitting device manufactured without a photolithography process is also highly stable to the atmosphere, so the yield is improved and the atmosphere management in the manufacturing process does not need to be too strict, which helps to reduce costs.

[0188] Implementation Method 2 In this embodiment, a light-emitting device which is one embodiment of the present invention is described in detail.

[0189] 1 is a schematic diagram of a light-emitting device according to one embodiment of the present invention. In the light-emitting device, a first electrode 101 is provided on an insulator 100, and an EL layer 103 is included between the first electrode 101 and the second electrode 102. The EL 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.

[0190] like Figure 1A As shown, the EL layer 103 preferably includes functional layers such as a hole injection layer 111, a hole transport layer 112, an electron transport layer 114, and an electron injection layer 115 in addition to the light-emitting layer 113. In addition, the EL layer 103 may also include functional layers other than the above functional layers, such as a hole blocking layer, an electron blocking layer, an exciton blocking layer, a charge generating layer, etc. Conversely, any of the above layers may not be provided.

[0191] In addition, the electron injection layer 115 is a layer including a metal or a metal oxide, an organic compound including a first π-deficient heteroaromatic ring having an electron-donating group (first organic compound), and an organic compound having a second π-deficient heteroaromatic ring (second organic compound) as described in Embodiment 1. The electron injection layer 115 may further include another organic compound (third organic compound).

[0192] The specific structure of the electron injection layer 115 has been described in detail in Embodiment 1, and thus repeated description is omitted here.

[0193] Note that although the example in which the first electrode 101 is an electrode including an anode, the second electrode 102 is an electrode including a cathode, and the first electrode 101 is formed on one side of the insulator 100 is shown in this embodiment, a structure in which the second electrode 102 is formed on one side of the insulator 100, i.e., a so-called reverse stacking structure, may also be adopted. In this case, the light-emitting device has a stacking structure in which the second electrode 102, the electron injection layer 115, (the electron transport layer 114,) the light-emitting layer 113, (the hole transport layer 112, the hole injection layer 111,) the first electrode 101 are stacked in sequence from the side of the insulator 100. When a light-emitting device with this reverse stacking structure is adopted, the relatively stable hole injection layer 111 becomes the surface, thereby realizing a light-emitting device with higher reliability.

[0194] The first electrode 101 and the second electrode 102 are formed into a single-layer structure or a stacked-layer structure. In the case of a stacked-layer structure, a layer in contact with the EL layer 103 serves as an anode or a cathode. When the electrode has a stacked-layer structure, there is no restriction on the work function of the layers other than the layer in contact with the EL layer 103, and the material can be selected based on the required characteristics such as resistance value, processing convenience, reflectivity, light transmittance, and stability.

[0195] The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a large work function (specifically, 4.0 eV or more). Specifically, examples include indium oxide-tin oxide (ITO: IndiumTinOxide), indium oxide-tin oxide containing silicon or silicon oxide (ITSO: IndiumTinSiliconOxide), indium oxide-zinc oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO), and the like. Although these conductive metals or their oxide films are usually formed by sputtering, they can also be formed by applying a sol-gel method. As an example of a formation method, a method of forming indium oxide-zinc oxide by sputtering using a target material having 1 wt% to 20 wt% of zinc oxide added to indium oxide can be cited. In addition, indium oxide (IWZO) containing tungsten oxide and zinc oxide can be formed by sputtering using a target material having 0.5 wt% to 5 wt% of tungsten oxide and 0.1 wt% to 1 wt% of zinc oxide 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 (e.g., titanium nitride) can be cited. In addition, the layers stacked thereon can also be used as anodes. For example, a film of Al, Ti, and ITSO stacked in sequence on Ti has high efficiency due to good reflectivity and can achieve a high resolution of thousands of ppi, so it is preferred. In addition, graphene can also be used as a material for the anode. In addition, by using a composite material that can constitute the hole injection layer 111 described later for a layer in contact with the anode (typically a hole injection layer), it is possible to select an electrode material without taking into account the work function.

[0196] The hole injection layer 111 is in contact with the anode and has a function of facilitating hole injection into the EL layer 103. The hole injection layer 111 can be formed using phthalocyanine compounds or complexes such as phthalocyanine (abbreviated as H2Pc) and copper phthalocyanine (abbreviated as CuPc); aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD); or polymers such as poly(3,4-ethylenedioxythiophene) / (polystyrenesulfonic acid) (abbreviated as PEDOT / PSS).

[0197] In addition, the hole injection layer 111 may be composed of a substance having electron acceptor properties. As the substance having electron acceptor properties, an organic compound having an electron withdrawing group (halogen group, cyano group) may be used, and examples thereof include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), and 2-(7-dicyano-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile. 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 and therefore are preferred. In addition, [3] axial ene derivatives containing electron-withdrawing groups (especially halogen groups such as fluorine groups, cyano groups, etc.) are particularly preferred because they have very high electron acceptor properties. Specifically, examples include: α, α', α"-1,2,3-cyclopropane trimethylene tris[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α, α', α"-1,2,3-cyclopropane trimethylene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α, α', α"-1,2,3-cyclopropane trimethylene tris[2,3,4,5,6-pentafluorophenylacetonitrile], etc. As substances having electron acceptor properties, in addition to the above-mentioned organic compounds, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can also be used.

[0198] The hole injection layer 111 is preferably formed using a composite material including the above-mentioned material having an electron accepting property and an organic compound having a hole transporting property.

[0199] As the organic compound with hole transport property used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, high molecular weight compounds (oligomers, dendrimers, polymers, etc.) can be used. As the organic compound with hole transport property used in the composite material, it is preferred to use an organic compound with a hole mobility of 1×10 -6 cm 2 / Vs or more organic compounds. The organic compound with hole transport properties used in the composite material is preferably a compound containing a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the fused aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferred. In addition, as the π-electron-rich heteroaromatic ring, a fused aromatic ring containing at least any one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton is preferred, specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are also fused with an aromatic ring or a heteroaromatic ring.

[0200] In addition, the composite material containing the material having electron acceptor properties and the organic compound having hole transport properties effectively causes interaction between the materials. Therefore, the spin density of the film containing the composite material measured by the electron spin resonance method (ESR) is preferably 1×10 17 spins / cm 3 above.

[0201] 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 a 9-fluorenyl group 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 groups, a light-emitting device with a long life can be manufactured, so it is preferred.

[0202] Specific examples of the organic compound having a hole transport property include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviated as BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4"-phenyltriphenylamine (abbreviated as BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviated as BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1 ,2-d]furan-8-amine (abbreviated as BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviated as BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviated as ThBA1BP), 4-(2-naphthyl)-4',4"-diphenyltriphenylamine (abbreviated as BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4"-diphenyltriphenylamine (abbreviated as BBAβNBi), 4,4'-diphenyl Phenyl-4"-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB), 4,4'-diphenyl-4"-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBAαNβNB-03), 4,4'-diphenyl-4"-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviated as: BBAPβNB-03), 4,4'-diphenyl-4"-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviated as: BBA(βN2)B), 4,4'-diphenyl-4"-(7;2'-binaphthyl-2-yl)-triphenylamine (abbreviated as: BBA(βN2)B-03), 4,4'-diphenyl-4"-(4;2'-binaphthyl- 1-yl) triphenylamine (abbreviated as: BBAβNαNB), 4,4'-diphenyl-4"-(5;2'-binaphthyl-1-yl) triphenylamine (abbreviated as: BBAβNαNB-02), 4-(4-biphenyl)-4'-(2-naphthyl)-4"-phenyltriphenylamine (abbreviated as: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4"-phenyltriphenylamine (abbreviated as: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviated as: 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]tri(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: PCBNB SF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviated as: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviated as: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)dibenzofuran-4-amine (abbreviated as: 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-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 9H-fluorene-2-amine (abbreviated as: 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-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-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-2-amine, N,N-bis(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobi-9H-fluorene-1-amine, etc.

[0203] In addition, as materials with hole transport 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.

[0204] By forming the hole injection layer 111, hole injection properties can be improved, so that a light-emitting device with a low driving voltage can be obtained.

[0205] Furthermore, among substances having electron accepting properties, organic compounds having accepting properties can be easily formed by vapor deposition and are therefore easy-to-use materials.

[0206] The hole transport layer 112 is formed of an organic compound having a hole transport property. The organic compound having a hole transport property preferably has a 1×10 -6 cm 2 / Vs and above hole mobility.

[0207] Examples of the hole-transporting material include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP). , 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluorene-2-amine (abbreviated as PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as PCBASF), etc.;1,3-Bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9 H,9'H-3,3'-bicarbazole (abbreviated as: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviated as: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviated as: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviated as: 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':3',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, Compounds having a carbazole skeleton such as carbazole, 9-(2-naphthyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviated as PCCzTp), 9,9'-bis(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenyl-2-yl)-3,3'-9H,9'H-bicarbazole, and 9-(triphenyl-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole;Compounds having a thiophene skeleton, such as 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV); and compounds having a furan skeleton, such as 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), and 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among them, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have high reliability and excellent hole transport properties and contribute to lowering the driving voltage. Note that as the material constituting the hole transport layer 112, the substances listed as the materials having hole transport properties for the composite material used for the hole injection layer 111 can also be appropriately used. ;

[0208] 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. Alternatively, two layers having different compositions may be stacked.

[0209] The light-emitting substance may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or other light-emitting substances.

[0210] In the light-emitting layer, materials that can be used as the fluorescent substance include, for example, the following substances. Note that other fluorescent substances can also be used.

[0211] Examples thereof include 5,6-bis[4-(10-phenyl-9-anthracenyl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthracenyl)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-fluorene-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviated as: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthracenyl)triphenylamine (abbreviated as: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2- triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butyl perylene (abbreviation: TBP), 4-(10-phenyl-9-anthracenyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N"-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene )bis(, N', N'-triphenyl-1,4-phenylenediamine) (abbreviated as: DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated as: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as: 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-anthracenyl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthracenyl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthracenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9 , 10-bis(biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviated as: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviated as: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviated as: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenylnaphthacene (abbreviated as: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malononitrile (abbreviated as: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizine-9- 1,2-diaminobenzene (abbreviated as: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)naphthocene-5,11-diamine (abbreviated as: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviated as: 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}malononitrile (abbreviated as: 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}malononitrile (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malononitrile (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}malononitrile (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-carbazole-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, condensed aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 are preferred because they have high hole-trapping properties, high luminous efficiency, and high reliability. ,

[0212] In addition, 5,9-diphenyl-5,9-diaza-13b-borazinahexano[3,2,1-de]anthracene (abbreviation: DABNA1), 9-(biphenyl-3-yl)-N,N,5,11-tetraphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazine-3-amine (abbreviation: DABNA2), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-N,N-diphenyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazine-3-amine (abbreviation: DABNA2), -7-amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetrakis(4-tert-butylphenyl)-5H,9H-[1,4]benzoazaboro[2,3,4-kl]phenazoneboro-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzoazaboro[2,3,4-kl]phenazoneboro (abbreviation: Me-tBu4DABNA), N 7 , N 7 , N 13 , N 13 , 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaboro[2,3,4-kl][1,4]benzazaboro[4',3',2':4,5][1,4]benzazaboro[3,2-b]phenazoboro-7,13-diamine (abbreviation: ν-DABNA), 2-(4-tert-butylphenyl)benzo[5,6]indole[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc) and other nitrogen- and boron-containing fused heteroaromatic compounds, especially compounds having a diaza-borazine-naphtho-anthracene skeleton, have a narrow emission spectrum and can obtain blue light emission with good color purity, so they can be appropriately used.

[0213] In addition to the above, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indol[3,2,1-de]indol[3',2',1':8,1][1,4]benzazaboro[2,3,4-kl]phenazoneboro (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazole-9-yl]-2,5,15,18-tetra(1,1-dimethylethyl)indol[3,2,1-de]indol[3',2',1':8,1][1,4]benzazaboro[2,3,4-kl]phenazoneboro (abbreviation: BBCz-Y), etc. can also be appropriately used.

[0214] When a phosphorescent substance is used as a light-emitting substance in the light-emitting layer, examples of usable materials include the following substances.

[0215] Examples include organic metal iridium complexes having a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Mptz)3]), and the like. tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]) and other organic metal iridium complexes having a 1H-triazole skeleton; fac-tris[1-(2,6-di isopropylphenyl)-2-phenyl-1H-imidazole]iridium (III) (abbreviated as [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium (III) (abbreviated as [Ir(dmpimpt-Me)3]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazole- 2-yl-κN3}-4-cyanophenyl-κC)(abbreviated as CNImIr) and the like having an imidazole skeleton; tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III)(abbreviated as [Ir(cb)3]) and the like having a benzimidazole skeleton; and bis[2-(4',6'-difluorophenyl)pyridinyl-N,C 2’]iridium(III)tetrakis(1-pyrazolyl)borate (abbreviated as FIr6), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ]iridium(III) picolinate (abbreviated as FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinium-N,C 2’ Iridium(III) picolinate (abbreviated as [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinium-N,C 2’ ] Iridium (III) acetylacetonate (abbreviated as FIr(acac)) and other organic metal iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand. The above substances are compounds that emit blue phosphorescence and have a luminescence peak in the wavelength region of 450nm to 520nm.

[0216] In addition, tris(4-methyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonate)bis(6-methyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonate)bis(6-tert-butyl-4-phenylpyrimidinyl)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonate)bis[6-(2-norbornyl)-4-phenylpyrimidinyl]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonate)bis[5-methyl [Ir(mppr-iPr)2(acac)]) and other organic metal iridium complexes with a pyrimidine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-Me)2(acac)] and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-iPr)2(acac)]; [Ir(mppr-iPr)2(acac)] and other organic metal iridium complexes with a pyrazine skeleton, such as tris(2-phenylpyridinium-N,C 2’ )iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinium-N,C 2’)iridium(III)acetylacetonate (abbreviated as [Ir(ppy)2(acac)]), bis(benzo[h]quinoline)iridium(III)acetylacetonate (abbreviated as [Ir(bzq)2(acac)]), tris(benzo[h]quinoline)iridium(III) (abbreviated as [Ir(bzq)3]), tris(2-phenylquinoline-N,C 2’ )iridium(III) (abbreviated as [Ir(pq)3]), bis(2-phenylquinoline-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridyl-κN)benzofurano[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)benzofurano[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 [Ir(ppy)2(mdppy)]), and other organic metal iridium complexes having a pyridine skeleton, such as [2-methyl-(2-pyridyl-κN)benzofurano[2,3-b]pyridine-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]), and [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 rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]). The above substances are mainly compounds that exhibit green phosphorescence and have a light emission peak in the wavelength region of 500 nm to 600 nm. In addition, since an organic metal iridium complex having a pyrimidine skeleton has particularly excellent reliability or light emission efficiency, it is particularly preferred.

[0217] In addition, organic gold metals having a pyrimidine skeleton include: (diisobutyrylmethane)bis[4,6-bis(3-methylphenyl)pyrimidinyl]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinyl](dipivaloylmethanone)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinyl](dipivaloylmethanone)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]) and the like. Iridium complexes; (acetylacetonato)bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazine)(dipivaloylmethanone)iridium(III) (abbreviated as [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxaline]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]) and other organometallic iridium complexes with pyrazine skeletons; tris(1-phenylisoquinoline-N,C 2’ )iridium(III) (abbreviated as [Ir(piq)3]), bis(1-phenylisoquinoline-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedione-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolyl-κN]phenyl-κC]iridium(III) and the like organic metal iridium complexes having a pyridine skeleton 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum (II) (abbreviated as PtOEP) and other platinum complexes; and tris (1,3-diphenyl-1,3-propanedione (propanedionato)) (monophenanthroline) europium (III) (abbreviated as [Eu (DBM) 3 (Phen)]), tris [1- (2-thenoyl) -3,3,3-trifluoroacetone] (monophenanthroline) europium (III) (abbreviated as [Eu (TTA) 3 (Phen)] and other rare earth metal complexes. The above substances are compounds that exhibit red phosphorescence and have a luminescence peak in the wavelength region of 600nm to 700nm. In addition, an organic metal iridium complex having a pyrazine skeleton can obtain red luminescence with good chromaticity.

[0218] Furthermore, in addition to the above-mentioned phosphorescent compounds, known phosphorescent compounds may be selected and used.

[0219] As TADF materials, fullerene and its derivatives, acridine and its derivatives, and eosin derivatives can be used. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) can also be mentioned. As the metal-containing porphyrin, for example, there can be mentioned 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)), protoporphyrin-tin fluoride complex (SnF2(Etio I)) and octaethylporphyrin-platinum chloride complex (PtCl2OEP) etc. represented by the following structural formula.

[0220] [Chemical formula 5]

[0221] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindol[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazine-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), and 2-[4-(10H-phenoxazine-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn) represented by the following structural formula can also be used. Heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, such as 3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthene-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridinium)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracenes]-10'-one (abbreviation: ACRSA). Such heterocyclic compounds having a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring have high electron transport properties and hole transport properties, and are therefore preferred. Among them, in the skeleton with 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 electron acceptor properties of the benzofuranopyrimidine skeleton, the benzothiophenopyrimidine skeleton, the benzofuranopyrazine skeleton, and the benzothiophenopyrazine skeleton are high and reliable, so they are preferred. In addition, in the skeleton with 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 a furan skeleton, a dibenzofuran skeleton is preferably used, and as a thiophene skeleton, a dibenzothiophene skeleton is preferably used. As a pyrrole skeleton, an indole skeleton, a carbazole skeleton, an indolecarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazole-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 that thermally activated delayed fluorescence can be obtained efficiently, so it is particularly preferred. Note that an aromatic ring bonded with an electron-withdrawing group such as a cyano group can also be used instead of a π-electron-deficient heteroaromatic ring. In addition, as a π-electron-rich skeleton, an aromatic amine skeleton, a phenazine skeleton, etc. can be used.In addition, as the π-electron-deficient skeleton, a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring or heteroaromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanophenyl, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. can be used. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used to replace at least one of the π-electron-deficient heteroaromatic ring and the π-electron-rich heteroaromatic ring.

[0222] [Chemical formula 6]

[0223] TADF materials refer to materials with a small difference between the S1 energy level and the T1 energy level and the function of converting triplet excitation energy into singlet excitation energy through anti-intersystem crossing. Therefore, it is possible to up-convert triplet excitation energy into singlet excitation energy (anti-intersystem crossing) through tiny thermal energy and efficiently generate singlet excited states. In addition, triplet excitation energy can be converted into luminescence.

[0224] The exciplex formed by two substances in an excited state has the function of a TADF material that can convert triplet excitation energy into singlet excitation energy because the difference between the S1 energy level and the T1 energy level is extremely small.

[0225] Note that as an indicator of the T1 level, a phosphorescence spectrum observed at a low temperature (e.g., 77 K to 10 K) can be used. With respect to the TADF material, when the wavelength energy of an extrapolated line obtained by cutting a line at the tail of the short wavelength side of the fluorescence spectrum is taken as the S1 level and the wavelength energy of an extrapolated line obtained by cutting a line at the tail of the short wavelength side of the phosphorescence spectrum is taken as the T1 level, it is preferred that the difference between the S1 level and the T1 level be 0.3 eV or less, more preferably 0.2 eV or less.

[0226] In addition, when a TADF material is used as a light-emitting 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.

[0227] As the host material of the light-emitting layer, various carrier transport materials such as a material having an electron transport property and / or a material having a hole transport property, and the above-mentioned TADF material can be used.

[0228] As the material having hole transport properties, it is preferred to use an organic compound having an amine skeleton, a π-electron-rich heteroaromatic ring skeleton, etc. As the π-electron-rich heteroaromatic ring, it is preferred to use a fused aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton, and specifically preferably a carbazole ring, a dibenzothiophene ring, or a ring in which these rings are further fused with an aromatic ring or a heteroaromatic ring.

[0229] 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 a 9-fluorenyl group 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 groups, a light-emitting device with a long life can be manufactured, so it is preferred.

[0230] Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviated as TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylfluorene-9-yl)triphenylamine (abbreviated as mBPAFLP), 4'-phenyl-4 ... -(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), 4,4'-diphenyl-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBANB), 4,4'-di(1-naphthyl)-4"-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviated as: PCBAF), N-phenyl -N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviated as PCBASF) and other compounds having an aromatic amine skeleton; 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviated as PCCP) and other compounds having a carbazole skeleton; 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as DB T3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]dibenzothiophene (abbreviated as: DBTFLP-III), 4-[4-(9-phenyl-9H-fluorene-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as: DBTFLP-IV) and other compounds having a thiophene skeleton; and 4,4',4"-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviated as: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluorene-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as: mmDBFFLBi-II) and other 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 transport properties and help to reduce the driving voltage, so they are preferred. In addition, organic compounds listed as examples of materials with hole transport properties as hole transport layers can also be used.

[0231] As materials having electron transport properties, for example, metal complexes such as bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq), bis[2-(2-benzoxazolyl)phenol]zinc(II) (abbreviated as ZnPBO), bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ) and organic compounds containing π-electron-deficient heteroaromatic rings are preferably used. As organic compounds containing π-electron-deficient heteroaromatic skeletons, for example, organic compounds containing heteroaromatic rings having azole skeletons, organic compounds containing heteroaromatic rings having pyridine skeletons, organic compounds containing heteroaromatic rings having diazine skeletons, and organic compounds containing heteroaromatic rings having triazine skeletons can be cited.

[0232] 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, so they are preferred. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage. In addition, benzofuranopyrimidine skeletons, benzothiophenopyrimidine skeletons, benzofuranopyrazine skeletons, and benzothiophenopyrazine skeletons have high electron acceptor properties and high reliability, so they are preferred.

[0233] Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2"-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[ 3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviated as BzOs), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB), bathophenanthroline (abbreviated as BPhen), bathocuproin (abbreviated as BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen), 2,2'-(1,3-phenylene)bis( Organic compounds containing a heteroaromatic ring having a pyridine skeleton, such as 2-[4-(9-phenanthrenyl)-1-naphthyl]-1,10-phenanthroline (abbreviation: PnNPhen), 2-[4-(2-triphenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen); 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDB); q-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mCzBPDBq), 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as: 2mPCCzPDBq), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophene-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), Furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophene-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-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-(dibenzothiophene-4-yl)phenyl]-[1]benzofuro[3, 2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1',2':4,5]furano[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]- [1] benzofurano[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthyl-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,organic compounds having a diazine skeleton, such as 4NP-6PyPPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviated as PC-cgDBCzQz); 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluorene]-2-yl)-1,3,5-triazine (abbreviated as BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]-1,3,5-triazine (abbreviated as BP-SFTzn), ] phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviated as mPCCzPTzn), Tzn-02), 2-[3'-(9,9-dimethyl-9H-fluorene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviated as: mINc(II)PTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazine-2-yl]-11,12-dihydro-12-phenyl-indolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylene-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviated as PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1"-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 2-[4-(2-naphthyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviated as βNP-SFx(4)Tzn), 2-phenyl Organic compounds containing heteroaromatic rings having a triazine skeleton, such as 4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviated as: mSiTrz). In addition, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, or organic compounds containing heteroaromatic rings having a triazine skeleton have high reliability and are therefore preferred. In particular, organic compounds containing heteroaromatic rings having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings having a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage. ,

[0234] As a TADF material that can be used as a host material, the same material as the material cited above as a TADF material can be used. When a TADF material is used as a host material, the triplet excitation energy generated by the TADF material is converted into singlet excitation energy through reverse intersystem crossing and further energy is transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. At this time, the TADF material is used as an energy donor and the luminescent material is used as an energy acceptor.

[0235] This is very effective when the above-mentioned luminescent material is a fluorescent luminescent material. In addition, at this time, in order to obtain high luminous efficiency, the S1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. In addition, the T1 energy level of the TADF material is preferably higher than the S1 energy level of the fluorescent luminescent material. Therefore, the T1 energy level of the TADF material is preferably higher than the T1 energy level of the fluorescent luminescent material.

[0236] In addition, it is preferable to use a TADF material that emits light at a wavelength overlapping with the absorption band on the lowest energy side of the fluorescent material. This is preferable because the excitation energy is smoothly transferred from the TADF material to the fluorescent material, and light emission can be obtained efficiently.

[0237] In order to efficiently generate singlet excitation energy from triplet excitation energy by anti-intersystem crossing, carrier recombination is preferably generated in TADF material. In addition, it is preferred that the triplet excitation energy generated in TADF material is not transferred to the triplet excitation energy of fluorescent material. For this reason, the fluorescent material preferably has a protecting group around the luminophore (the skeleton that becomes the cause of luminescence) possessed by the fluorescent material. As the protecting group, it is preferably a substituent without a π bond, preferably a saturated hydrocarbon, specifically, an alkyl group having a carbon number of more than 3 and less than 10, a substituted or unsubstituted cycloalkyl group having a carbon number of more than 3 and less than 10, and a trialkylsilyl group having a carbon number of more than 3 and less than 10, more preferably having a plurality of protecting groups. The substituent without a π bond has almost no function of transmitting carriers, so it has almost no effect on carrier transmission or carrier recombination, and the luminophore of the TADF material and the fluorescent material can be kept away from each other. Here, the luminophore refers to the atomic group (skeleton) that becomes the cause of luminescence in the fluorescent material. The luminophore preferably has a π-bond skeleton, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of the luminophore include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, In particular, the naphthalene skeleton, the anthracene skeleton, the fluorene skeleton, the Fluorescent substances having a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because they have high fluorescence quantum yields.

[0238] In the case where a fluorescent luminescent substance is used as a luminescent substance, a material having an anthracene skeleton is preferably used as a host material. By using a substance having an anthracene skeleton as a host material of a fluorescent luminescent substance, a light-emitting layer having high luminous efficiency and durability can be achieved. Among the substances having an anthracene skeleton used as a host material, substances having a diphenylanthracene skeleton, especially a 9,10-diphenylanthracene skeleton, are chemically stable, so they are preferred. In addition, in the case where the host material has a carbazole skeleton, the injection / transport properties of holes are improved, so it is preferred. In the case of a benzocarbazole skeleton comprising a benzene ring fused to carbazole, its HOMO energy level is about 0.1eV shallower than when the carbazole skeleton is included, and holes are easily injected, so it is more preferred. In particular, in the case where the host material has a dibenzocarbazole skeleton, its HOMO energy level is about 0.1eV shallower than when the carbazole skeleton is included, and not only holes are easily injected, but also hole transport and heat resistance are improved, so it is preferred. Therefore, a more preferred host material is one having a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). Note that from the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton. Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthracenyl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthracenyl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviated as 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]- 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-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-{4-[10-(biphenyl-4-yl)-9-anthracenyl]phenyl}-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), and the like. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred because they exhibit very good properties.

[0239] In addition, the host material may also be a material mixed with multiple substances. When a mixed host material is used, it is preferred to mix a material having an electron transport property and a material having a hole transport property. By mixing a material having an electron transport property and a material having a hole transport property, it is easier to adjust the transport property of the light-emitting layer 113, and it is also easier to control the recombination area. The weight ratio of the content of the material having a hole transport property and the material having an electron transport property may be 1:19 to 19:1.

[0240] Note that as part of the above mixed material, a phosphorescent substance may be used. When a fluorescent substance is used as a light-emitting substance, the phosphorescent substance may be used as an energy donor for supplying excitation energy to the fluorescent substance.

[0241] In addition, these mixed materials can also be used to form an exciplex. By selecting a mixed material in a manner to form an exciplex that emits light overlapping the wavelength of the absorption band on the lowest energy side of the luminescent substance, energy transfer can be smoothed, thereby efficiently obtaining luminescence, so it is preferred. In addition, by adopting this structure, the driving voltage can be reduced, so it is preferred.

[0242] Note that at least one of the materials forming the exciplex may be a phosphorescent substance. This allows efficient conversion of triplet excitation energy into singlet excitation energy via anti-intersystem crossing.

[0243] Regarding the combination of materials that efficiently form an exciplex, the HOMO energy level of the material having hole transport properties is preferably higher than the HOMO energy level of the material having electron transport properties. In addition, the LUMO energy level of the material having hole transport properties is preferably higher than the LUMO energy level of the material having electron transport properties. Note that the LUMO energy level and HOMO energy level of the material can be obtained from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0244] Note that the formation of an exciplex can be confirmed, for example, by comparing the emission spectra of a material having hole transport properties, the emission spectra of a material having electron transport properties, and the emission spectra of a mixed film formed by mixing these materials. When the emission spectrum of the mixed film is observed to drift toward the long wavelength side compared to the emission spectrum of each material (or to have a new peak on the long wavelength side), it indicates that an exciplex has been formed. Alternatively, the transient photoluminescence (PL) of a material having hole transport properties, the transient PL of a material having electron transport properties, and the transient PL of a mixed film formed by mixing these materials are compared. When the transient response is different, such as the ratio of the transient PL lifetime of the mixed film to the transient PL lifetime of each material is increased, it indicates that an exciplex has been formed. In addition, the above-mentioned transient PL can be referred to as transient electroluminescence (EL). In other words, the formation of an exciplex can be confirmed by comparing the transient EL of a material having hole transport properties, the transient EL of a material having electron transport properties, and the transient EL of a mixed film of these materials and observing the difference in transient response.

[0245] The electron transport layer 114 is a layer containing a substance having an electron transport property. As the material having an electron transport property, it is preferable to use a material having an electron mobility of 1×10 -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 / Vs or more. In addition, as long as the electron transport property is higher than the hole transport property, substances other than the above may also be used. As the above-mentioned organic compound, it is preferred to use an organic compound containing a π-electron-deficient heteroaromatic ring. As an organic compound containing a π-electron-deficient heteroaromatic ring, for example, it is preferred to use an organic compound containing a heteroaromatic ring having an azole skeleton, an organic compound containing a heteroaromatic ring having a pyridine skeleton, an organic compound containing a heteroaromatic ring having a diazine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton.

[0246] As an organic compound with electron transport properties that can be used for the above-mentioned electron transport layer 114, the organic compound with electron transport properties in the above-mentioned light-emitting layer 113 and the organic compound exemplified as the second organic compound that can be used for the electron injection layer 115 in Embodiment 1 can be used in the same manner. Among them, organic compounds containing heteroaromatic rings with a diazine skeleton, organic compounds containing heteroaromatic rings with a pyridine skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton have good reliability, so they are preferred. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing heteroaromatic rings with a triazine skeleton have high electron transport properties, which helps to reduce the driving voltage. In particular, organic compounds with a phenanthroline skeleton such as mTpPPhen, PnNPhen and mPPhen2P are preferred, and organic compounds with a phenanthroline dimer structure such as mPPhen2P have excellent stability, so they are more preferred. In addition, it is preferable to use an organic compound having an 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.

[0247] Furthermore, the electron transport layer preferably comprises an acid having an acid dissociation constant pK a An organic compound with an electron transport property of less than 4.

[0248] 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 deeper than the HOMO level of the material contained in the light-emitting layer by 0.5 eV or more.

[0249] The 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.

[0250] The second electrode 102 is an electrode including a cathode. The second electrode 102 may also have a stacked structure, in which case the layer in contact with the EL layer 103 is used as a cathode. As a material forming the cathode, a metal, an alloy, a conductive compound, and a mixture thereof having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), or strontium (Sr), alloys containing them (MgAg, AlLi), compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), etc.), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing them. However, by providing an electron injection layer 115 or a thin film of the above-mentioned material with a small work function between the second electrode 102 and the electron transport layer, various conductive materials such as Al, Ag, ITO, indium oxide-tin oxide containing silicon or silicon oxide, etc. can be used as cathodes regardless of the size of the work function.

[0251] When the second electrode 102 is composed of a material that is transparent to visible light, a light-emitting device that emits light from the second electrode 102 side can be formed. When the first electrode 101 is composed of a material that is transparent to visible light, a light-emitting device that emits light from the first electrode 101 side can be formed.

[0252] These conductive materials can be formed by dry methods such as vacuum deposition and sputtering, inkjet, spin coating, etc. Alternatively, they can be formed by wet methods such as sol-gel or by wet methods using a paste of a metal material.

[0253] In addition, when it is a top-emitting light-emitting device, the light extraction efficiency can be improved by evaporating an organic compound on the second electrode to form a cap layer. The cap 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.

[0254] The EL layer 103 can be formed by any of a variety of methods, whether dry or wet. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet, or spin coating can be used.

[0255] Furthermore, the electrodes or layers described above may also be formed by using different deposition methods.

[0256] Next, refer to Figure 1B A 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 tandem device). The light-emitting device is a light-emitting device having a plurality of light-emitting units between an anode and a cathode. Figure 1AThe EL layer 103 shown in FIG. 1 has a substantially similar structure. That is, it can be said that Figure 1B The light emitting device shown is a light emitting device having a plurality of light emitting units. Figure 1A The light-emitting device shown is a light-emitting device having one light-emitting unit.

[0257] exist Figure 1B In the embodiment, a first light-emitting unit 511 and a second light-emitting unit 512 are stacked between the first electrode 501 and the 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 are respectively equivalent to Figure 1A The first electrode 101 and the second electrode 102 in the embodiment of the present invention can be applied to Figure 1A In addition, the first light emitting unit 511 and the second light emitting unit 512 may have the same structure or different structures.

[0258] The intermediate layer 513 has a function of injecting electrons into one light-emitting unit and injecting holes into the other light-emitting unit when a voltage is applied to the first electrode 501 and the second electrode 502. Figure 1B When a voltage is applied so that the potential of the anode is higher than the potential of the cathode, the intermediate layer 513 may be a layer that injects electrons into the first light-emitting unit 511 and injects holes into the second light-emitting unit 512 .

[0259] The intermediate layer 513 includes a charge generating layer. In addition, the charge generating layer includes at least a P-type layer 117. The P-type layer 117 is preferably formed using the composite material constituting the hole injection layer 111. In addition, the P-type layer 117 can also be formed by stacking a film containing the above-mentioned acceptor material and a film containing a hole transport material as a material constituting the composite material. By applying a potential to the P-type layer 117, electrons and holes are injected into the electron transport layer 114 and the cathode, respectively, so that the light-emitting device works.

[0260] In addition, the intermediate layer 513 preferably includes one or both of the electron relay layer 118 and the N-type layer 119 in addition to the P-type layer 117 .

[0261] The electron relay layer 118 contains at least a substance with electron transport properties, and can prevent the interaction between the N-type layer 119 and the P-type layer 117, and smoothly transfer electrons. The LUMO energy level of the substance with electron transport properties contained in the electron relay layer 118 is preferably set between the LUMO energy level of the acceptor substance in the P-type layer 117 and the LUMO energy level of the substance contained in the layer in contact with the intermediate layer 513 in the electron transport layer 114. Specifically, the LUMO energy level of the substance with electron transport properties in the electron relay layer 118 is above -5.0 eV, preferably above -5.0 eV and below -3.0 eV. In addition, as the substance with electron transport properties in the electron relay layer 118, it is preferred to use a phthalocyanine material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0262] The N-type layer 119 can use materials 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 rare earth metal compounds (including oxides, halides, carbonates)).

[0263] In addition, when the N-type layer 119 contains a substance having 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 rare earth metal compounds (including oxides, halides, carbonates)), tetrathianaphthacene (abbreviated as: TTN), nickelocene, decamethylnickelocene and other organic compounds can also be used. In addition, as a substance having electron transport properties, the same material as the material for the electron transport layer 114 described above can be used.

[0264] Alternatively, a layer containing the following organic compounds may be provided at the same position as the N-type layer 119 instead of the N-type layer 119: an organic compound containing a metal or metal oxide and a first π-electron-deficient heteroaromatic ring having an electron-donating group (first organic compound) and an organic compound having a second π-electron-deficient heteroaromatic ring (second organic compound) described as a layer used as an electron injection layer in Embodiment 1. When this structure is adopted, a tandem light-emitting device having good characteristics can also be manufactured.

[0265] In the case where the surface on the anode side of the light-emitting unit contacts the intermediate layer 513, the charge generation layer of the intermediate layer 513 can also function as the hole injection layer of the light-emitting unit, so the light-emitting unit may not be provided with a hole injection layer. In the case where the surface on the cathode side of the light-emitting unit contacts the intermediate layer 513, the intermediate layer 513 can also function as the electron injection layer of the light-emitting unit, so the light-emitting unit may not be provided with an electron injection layer.

[0266] Although in Figure 1B , a light-emitting device having two light-emitting units is described, but a light-emitting device having three or more light-emitting units stacked can be similarly applied. As in the light-emitting device according to this embodiment, by separating and arranging a plurality of light-emitting units between a pair of electrodes using an intermediate layer 513, an element can be realized that can achieve high-brightness light emission while maintaining a low current density and has a long life. In addition, a light-emitting device that can be driven at a low voltage and has low power consumption can be realized.

[0267] Furthermore, by making the emission colors of each light-emitting unit different, the desired color of light can be obtained in the entire light-emitting device. For example, by obtaining red and green emission colors from the first light-emitting unit and blue emission color from the second light-emitting unit in a light-emitting device having two light-emitting units, a light-emitting device that emits white light in the entire light-emitting device can be obtained.

[0268] In addition, the EL layer 103, the first light-emitting unit 511, the second light-emitting unit 512, the intermediate layer 513 and other layers and electrodes can be formed by, for example, evaporation (including vacuum evaporation), droplet jetting (also known as inkjet), coating, gravure printing, etc. In addition, they can also include low molecular weight materials, medium molecular weight materials (including oligomers, dendrimers) or high molecular weight materials.

[0269] Figure 2A The diagram shows two adjacent light-emitting devices (a light-emitting device 130 a and a light-emitting device 130 b ) included in a display device according to one embodiment of the present invention.

[0270] The light-emitting device 130a includes an EL layer 103a between a first electrode 101a on an insulating layer 175 and a second electrode 102 opposite to the first electrode 101a. Although the EL layer 103a is shown to include a hole injection layer 111a, a hole transport layer 112a, a light-emitting layer 113a, an electron transport layer 114a, and an electron injection layer 115a, the EL layer 103a may have a stacked structure different from the above structure.

[0271] The light-emitting device 130b includes an EL layer 103b between a first electrode 101b on an insulating layer 175 and a second electrode 102 opposite to the first electrode 101b. Although the EL layer 103b is shown to include 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 EL layer 103b may also have a stacked structure different from the above structure.

[0272] The structures of the electron transport layer 114a and the electron injection layer 115a in the light-emitting device 130a and the electron transport layer 114b and the electron injection layer 115b in the light-emitting device 130b preferably adopt the structures described in Embodiment 1.

[0273] The second electrode 102 is preferably a continuous layer shared by the light-emitting device 130a and the light-emitting device 130b. In addition, the EL layer 103a and the EL layer 103b are processed by photolithography after the electron injection layer 115a is formed and after the electron injection layer 115b is formed, respectively, so they are independent of each other. A light-emitting device of one embodiment of the present invention can obtain a light-emitting device with good characteristics even if it is processed by photolithography after the electron injection layer 115a is formed and after the electron injection layer 115b is formed. In addition, as Fig.22A As shown, the electron injection layer 115a and the electron injection layer 115b may also be a continuous layer shared by the light emitting device 130a and the light emitting device 130b.

[0274] The end portion (outline) of the EL layer 103a is processed by photolithography so as to be substantially aligned in a direction perpendicular to the substrate. The end portion (outline) of the EL layer 103b is processed by photolithography so as to be substantially aligned in a direction perpendicular to the substrate.

[0275] In addition, due to photolithography, a gap d exists between the EL layer 103a and the EL layer 103b. In addition, by processing the EL layer by photolithography, the distance between the first electrode 101a and the first electrode 101b can be made smaller than that during mask deposition and can be made not less than 0.5 μm and not more than 5 μm.

[0276] Figure 2B The diagram shows two adjacent tandem light-emitting elements (light-emitting device 130c and light-emitting device 130d) manufactured by photolithography.

[0277] The light-emitting device 130c includes an EL layer 103c between a first electrode 101c and a second electrode 102 on an insulating layer 175. The EL layer 103c has a structure in which a first light-emitting unit 501c and a second light-emitting unit 502c are stacked via an intermediate layer 116c. Note that although FIG. 2 shows an example in which two light-emitting units are stacked, three or more light-emitting units may be stacked. The first light-emitting unit 501c includes a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 116c includes a P-type layer 117c, an electron relay layer 118c, and an N-type layer 119c. The presence or absence of the electron relay layer 118c is irrelevant. 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.

[0278] The light-emitting device 130d includes an EL layer 103d between a first electrode 101d and a second electrode 102 on an insulating layer 175. The EL layer 103d has a structure in which a first light-emitting unit 501d and a second light-emitting unit 502d are stacked via an intermediate layer 116d. Note that although FIG. 2 shows an example in which two light-emitting units are stacked, three or more light-emitting units may be stacked. The first light-emitting unit 501d includes a hole injection layer 111d, a first hole transport layer 112d_1, a first light-emitting layer 113d_1, and a first electron transport layer 114d_1. The intermediate layer 116d includes a P-type layer 117d, an electron relay layer 118d, and an N-type layer 119d. The presence or absence of the electron relay layer 118d is irrelevant. 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.

[0279] In the light-emitting device 130c and the light-emitting device 130d, the electron injection layer 115c and the electron injection layer 115d preferably have the structure described in Embodiment 1.

[0280] The second electrode 102 is preferably a continuous layer shared by the light-emitting device 130c and the light-emitting device 130d. In addition, the EL layer 103c and the EL layer 103d are processed by photolithography after the electron injection layer 115c is formed and after the electron injection layer 115d is formed, respectively, so they are independent of each other. A light-emitting device of one embodiment of the present invention can obtain a light-emitting device with good characteristics even if it is processed by photolithography after the electron injection layer 115c is formed and after the electron injection layer 115d is formed. In addition, as Fig. 22B As shown, the electron injection layer 115c and the electron injection layer 115d may also be a continuous layer shared by the light-emitting device 130c and the light-emitting device 130d.

[0281] The end portion (outline) of the EL layer 103c is processed by photolithography so as to be substantially aligned in a direction perpendicular to the substrate. The end portion (outline) of the EL layer 103d is processed by photolithography so as to be substantially aligned in a direction perpendicular to the substrate.

[0282] In addition, due to the photolithography process, a gap d exists between the EL layer 103c and the EL layer 103d. In addition, by processing the EL layer by photolithography, the distance between the first electrode 101c and the first electrode 101d can be made smaller than that during mask deposition and can be made not less than 0.5 μm and not more than 5 μm.

[0283] The light-emitting device of one embodiment of the present invention processes the EL layer by photolithography, and can be processed with sufficient accuracy, thereby manufacturing a high-definition display device. In addition, since the photolithography process can be performed on the electron injection layer away from the light-emitting layer without being contaminated by alkali metals, a light-emitting device with good characteristics can be realized. As described above, the light-emitting device of one embodiment of the present invention having the above-mentioned structure can realize a high-definition display device and a light-emitting device with good characteristics.

[0284] In addition, since the EL layer of the light-emitting device of one embodiment of the present invention is processed at one time by photolithography, the contours of the layers included in the EL layer are substantially consistent. Here, "substantially consistent" in this specification means that the difference between the contour A of the layer A and the contour B of the layer B included in the EL layer is within 5% of the width of the EL layer on a line perpendicular to the contour of the portion to be compared. In addition, when the end face of the EL layer is tapered, continuous change of the contour is allowed.

[0285] The structure of this embodiment can be used in combination with other structures as appropriate.

[0286] Implementation 3 In this embodiment, an embodiment in which a light-emitting device which is one embodiment of the present invention is used as a display element of a display device is described.

[0287] like Figure 3A and Figure 3B As shown, a plurality of light emitting devices 130 are formed on an insulating layer 175 and constitute a display device.

[0288] 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.

[0289] In this specification, for example, when describing the common contents among sub-pixel 110R, sub-pixel 110G, and sub-pixel 110B, sub-pixel 110 may be referred to as sub-pixel 110. Similarly, when describing the common contents among other components distinguished by letters, the letters may be omitted.

[0290] Sub-pixel 110R emits red light, sub-pixel 110G emits green light, and sub-pixel 110B emits blue light. Thus, a full-color image can be displayed on the pixel portion 177. In the present embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are used as examples for explanation, but a combination of sub-pixels of other colors may also be used. In addition, the number of sub-pixels is not limited to three, and four or more may also be used. As four sub-pixels, for example, there may be: 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); and the like.

[0291] In this specification and the like, the row direction may be referred to as the X direction and the column direction may be referred to as the Y direction. The X direction and the Y direction intersect, for example, perpendicularly intersect.

[0292] exist Figure 3A In the example shown, sub-pixels of different colors are arranged in the X direction, and sub-pixels of the same color are arranged in the Y direction. Note that sub-pixels of different colors may be arranged in the Y direction, and sub-pixels of the same color may be arranged in the X direction.

[0293] 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 EL layer 103 is provided in the region 141. In addition, the connection portion 140 is provided with a conductive layer 151C.

[0294] 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, but there is no particular limitation on the positions of the region 141 and the connection portion 140. In addition, the region 141 and the connection portion 140 may be one or more.

[0295] Figure 3B It is along Figure 3A An example of a cross-sectional view along the dot-dash line A1-A2 in FIG. Figure 3BAs shown, the display device includes an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is disposed on a substrate (not shown). The insulating layer 175, the insulating layer 174, and the insulating layer 173 are provided with openings that reach the conductive layer 172, and a plug 176 is provided in a manner of being embedded in the opening.

[0296] In the pixel portion 177, the 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 the resin layer 122. In addition, 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.

[0297] Figure 3B Although the cross sections of the plurality of inorganic insulating layers 125 and the plurality of insulating layers 127 are shown, the inorganic insulating layers 125 and the insulating layers 127 are preferably formed as one layer connected to each other when the display device is viewed from above. In other words, the insulating layer 127 is preferably an insulating layer having an opening on the first electrode.

[0298] exist Figure 3B 130R, 130G, and 130B are shown as the light emitting devices 130. The light emitting devices 130R, 130G, and 130B may emit light of different colors from each other. For example, the light emitting device 130R may emit red light, the light emitting device 130G may emit green light, and the light emitting device 130B may emit blue light. In addition, the light emitting device 130R, the light emitting device 130G, or the light emitting device 130B may also emit other visible light or infrared light.

[0299] The display device of one embodiment of the present invention may have, for example, a top emission structure that emits light in a direction opposite to a substrate on which a light-emitting device is formed. Alternatively, the display device of one embodiment of the present invention may have a bottom emission structure.

[0300] The light-emitting device 130R has the structure described 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 EL layer 103R on the first electrode 101R, and a second electrode 102 (common electrode) on the EL layer 103R. The electron injection layer, which is the outermost surface layer of the EL layer 103R, has the structure described in Embodiment 1. By having this structure, damage to the light-emitting layer or the active layer during the photolithography process can be suppressed, and good film quality and electrical properties can be expected. In addition, when the electron transport layer is a mixed layer of an organic compound having an electron transport property and an organic compound having a hole transport property, a display device in which a rise in driving voltage is suppressed can be realized.

[0301] The light-emitting device 130G has the structure described 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 EL layer 103G on the first electrode 101G, and a second electrode 102 (common electrode) on the EL layer 103G. The electron injection layer, which is the outermost surface layer of the EL layer 103G, has the structure described in Embodiment 1. By having this structure, damage to the light-emitting layer or the active layer during the photolithography process can be suppressed, and good film quality and electrical properties can be expected. In addition, when the electron transport layer is a mixed layer of an organic compound having an electron transport property and an organic compound having a hole transport property, a display device in which a rise in driving voltage is suppressed can be realized.

[0302] The light-emitting device 130B has the structure described in Embodiment 1 and Embodiment 2. It includes a first electrode 101B (pixel electrode) composed of a conductive layer 151B and a conductive layer 152B, an EL layer 103B on the first electrode 101B, and a second electrode 102 (common electrode) on the EL layer 103B. The electron injection layer, which is the outermost surface layer of the EL layer 103B, has the structure described in Embodiment 1. By having this structure, damage to the light-emitting layer or the active layer during the photolithography process can be suppressed, and good film quality and electrical properties can be expected. In addition, when the electron transport layer is a mixed layer of an organic compound having an electron transport property and an organic compound having a hole transport property, a display device in which a rise in driving voltage is suppressed can be realized.

[0303] One of the pixel electrode (first electrode) and the common electrode (second electrode) included in the light emitting device is used as an anode, and the other is used as a cathode. In this embodiment, unless otherwise specified, it is sometimes assumed that the pixel electrode is used as an anode and the common electrode is used as a cathode.

[0304] The EL layer 103R, the EL layer 103G, and the EL layer 103B are island layers that are independent in each light-emitting device or for each light-emitting color. Note that the EL layer 103R, the EL layer 103G, and the EL layer 103B preferably do not overlap each other. By setting the EL layer 103 in 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. As a result, 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.

[0305] The island-shaped EL layer 103 is formed by depositing an EL film and processing the EL film by photolithography.

[0306] The EL layer 103 is preferably provided so as to cover the top surface and the side surface of the first electrode 101 (pixel electrode) of the light-emitting device 130. Thus, compared with a structure in which the end of the EL layer 103 is located inside the end of the pixel electrode, it is easy to increase the aperture ratio of the display device. In addition, by covering the side surface of the pixel electrode of the light-emitting device 130 with the EL layer 103, the pixel electrode can be prevented from contacting the second electrode 102, and thus a short circuit of the light-emitting device 130 can be prevented.

[0307] In the display device of one embodiment of the present invention, the first electrode 101 (pixel electrode) of the light-emitting device preferably has a stacked structure. Figure 3B In the illustrated example, the first electrode 101 of the light-emitting device 130 has a stacked-layer structure of a conductive layer 151 provided on the insulating layer 171 side and a conductive layer 152 provided on the EL layer side.

[0308] For example, a metal material can be used as the conductive layer 151. 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 alloys obtained by appropriately combining these metals can be used.

[0309] As the conductive layer 152, an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used. For example, it is preferable to use a conductive oxide containing one or more of indium oxide, indium tin oxide, indium zinc oxide, zinc oxide, zinc oxide containing gallium, titanium oxide, indium zinc oxide containing gallium, indium zinc oxide containing aluminum, indium tin oxide containing silicon, and indium zinc oxide containing silicon. In particular, indium tin oxide containing silicon has a large work function, for example, 4.0 eV or more, so it can be preferably used as the conductive layer 152.

[0310] Each of the conductive layer 151 and the conductive layer 152 may have a stacked structure including a plurality of layers of different materials. In this case, the conductive layer 151 may include a layer using a material that can be used for the conductive layer 152 such as a conductive oxide, and the conductive layer 152 may include a layer using a material that can be used for the conductive layer 151 such as a metal material. For example, when the conductive layer 151 has a stacked 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.

[0311] Figure 3B The end of the conductive layer 151 in the embodiment preferably has a tapered shape. Specifically, the end of the conductive layer 151 preferably has a tapered shape with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side 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 EL layer 103 provided along the side of the conductive layer 152 can be improved.

[0312] In addition, the ends of the conductive layer 151 and the conductive layer 152 do not need to have a tapered shape, that is, they may be substantially vertical. In addition, the end of the EL layer 103 is preferably located on the inner side of the first electrode 101. In this case, leakage current through the EL layer 103 can be reduced, thereby obtaining a display device with low driving voltage and good display performance.

[0313] In the display device of one embodiment of the present invention, the light-emitting device 130 has the structure described in Embodiment 1 or Embodiment 2, whereby a light-emitting device with high reliability can be implemented.

[0314] Next, the method having the Figure 3A An example of a method for manufacturing a display device having the structure shown.

[0315] [Manufacturing method example] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), Atomic Layer Deposition (ALD), etc.

[0316] In addition, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using wet deposition methods such as spin coating, dipping, spraying, inkjet, dispenser, screen printing, offset printing, doctor knife, slit coating, roll coating, curtain coating or doctor knife coating.

[0317] In addition, when processing a thin film constituting the display device, it is possible to perform processing using, for example, photolithography.

[0318] In the photolithography method, as the light used for exposure, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm) or a mixture of these lights can be used. In addition, ultraviolet light, KrF laser or ArF laser, etc. can also be used. In addition, exposure can also be performed using liquid immersion exposure technology. In addition, as the light used for exposure, extreme ultraviolet (EUV: Extreme Ultra-violet) light or X-rays can also be used. In addition, instead of the light used for exposure, an electron beam can also be used.

[0319] For etching of the thin film, dry etching, wet etching, sand blasting, or the like can be used.

[0320] First, if Figure 4A As shown in the figure, an insulating layer 171 is formed on a substrate (not shown). Then, 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. Then, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0321] As the substrate, a substrate having heat resistance at least enough to withstand the subsequent heat treatment can be used. For example, 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 or silicon carbide, a compound semiconductor substrate such as silicon germanium, an SOI substrate, etc. can be used.

[0322] Then, if Figure 4A As shown in FIG. 1 , 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 be embedded in the opening.

[0323] Then, if Figure 4A As shown, a conductive film 151f which becomes the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, and the conductive layer 151C, and a conductive film 152f which becomes 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.

[0324] Then, if Figure 4AAs shown in FIG. 1 , a resist mask 191 is formed on the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist), exposing it to light, and developing it.

[0325] Then, if Figure 4B As shown in FIG. 1 , for example, the conductive film 151f and the conductive film 152f are removed in a region that does not overlap with the resist mask 191. Thus, the conductive layer 151 and the conductive layer 152 are formed.

[0326] Then, if Figure 4C As shown, the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, for example.

[0327] Then, if Figure 4D As shown, an insulating film 156f, which 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.

[0328] The insulating film 156f can be formed using an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. For example, silicon oxynitride can be used.

[0329] Then, if Figure 4E As shown, by processing the insulating film 156f, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B and the insulating layer 156C are formed.

[0330] Then, if Figure 5A As shown in FIG. 1 , the organic compound film 103Rf is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, and the insulating layer 175. Figure 5A As shown, the organic compound film 103Rf is not formed on the conductive layer 152C.

[0331] Then, if Figure 5A As shown, a sacrificial film 158Rf and a mask film 159Rf are formed.

[0332] By providing the sacrificial film 158Rf on the organic compound film 103Rf, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0333] The sacrificial film 158Rf is a film having high resistance to the processing conditions of the organic compound film 103Rf, specifically, a film having a large etching selectivity ratio with the organic compound film 103Rf. The mask film 159Rf is a film having a large etching selectivity ratio with the sacrificial film 158Rf.

[0334] In addition, the sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat resistance 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. to 200° C., preferably 100° C. to 150° C., and more preferably 100° C. to 120° C.

[0335] As the sacrificial film 158Rf and the mask film 159Rf, a film that can be removed by a wet etching method or a dry etching method is preferably used.

[0336] The sacrificial film 158Rf formed in contact with the organic compound film 103Rf is preferably formed by a formation method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, ALD or vacuum deposition is more preferable than sputtering.

[0337] 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.

[0338] 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 the metal materials can be used. In particular, low melting point materials such as aluminum and silver are preferably used. By using a metal material that can shield ultraviolet rays as one or both of the sacrificial film 158Rf and the mask film 159Rf, it is possible to suppress ultraviolet rays from irradiating the organic compound film 103Rf during pattern exposure and suppress the degradation of the organic compound film 103Rf, which is preferred.

[0339] 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.

[0340] Note that 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 instead of the above-mentioned gallium.

[0341] For example, it is preferable to use a semiconductor material such as silicon or germanium as the sacrificial film 158Rf and the mask film 159Rf because this material has high affinity with the semiconductor manufacturing process. Alternatively, a compound containing the above semiconductor material may be used.

[0342] Various inorganic insulating films can be used as the sacrificial film 158Rf and the mask film 159Rf, respectively. In particular, an oxide insulating film is preferred because it has higher adhesion to the organic compound film 103Rf than a nitride insulating film.

[0343] Then, if Figure 5A As shown, a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive material (photoresist), exposing and developing the same.

[0344] Resist mask 190R is provided at a position overlapping conductive layer 152R. Resist mask 190R is preferably provided also at a position overlapping conductive layer 152C. This can prevent conductive layer 152C from being damaged during the manufacturing process of the display device.

[0345] Then, if Figure 5B As shown, a portion 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, a portion of the sacrificial film 158Rf is removed using the mask layer 159R as a mask (also referred to as a hard mask) to form a sacrificial layer 158R.

[0346] By using the wet etching method, the damage to the organic compound film 103Rf during the processing of the sacrificial film 158Rf and the mask film 159Rf can be reduced compared to the case of using the dry etching method. When the wet etching method is used, for example, it is preferable to use a developer, an alkali aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, an acid aqueous solution such as a chemical solution of dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixed liquid thereof.

[0347] In addition, when dry etching is used in processing the sacrificial film 158Rf, degradation of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0348] The resist mask 190R can be removed by the same method as the resist mask 191 .

[0349] Then, if Figure 5BAs shown, the organic compound film 103Rf is processed to form the EL layer 103R. For example, the mask layer 159R and the sacrifice layer 158R are used as a hard mask and a part of the organic compound film 103Rf is removed, thereby forming the EL layer 103R.

[0350] Therefore, if Figure 5B As shown, the stacked structure of the EL layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. In addition, the conductive layer 152G and the conductive layer 152B are exposed.

[0351] The processing of the organic compound film 103Rf is preferably performed using anisotropic etching, and anisotropic dry etching is particularly preferred. Alternatively, wet etching may be used.

[0352] When the dry etching method is used, by not using an oxygen-containing gas as an etching gas, degradation of the organic compound film 103Rf can be suppressed.

[0353] In addition, an oxygen-containing gas may be used as the etching gas. When the etching gas contains oxygen, the etching rate can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficient etching rate. Therefore, damage to the organic compound film 103Rf can be suppressed. In addition, defects such as adhesion of reaction products generated during etching can be suppressed.

[0354] When using the dry etching method, for example, it is preferred to use a gas containing one or more of the 18th group elements such as H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, He, Ar as the etching gas. Alternatively, it is preferred to use a gas containing one or more of the above gases and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas.

[0355] Then, if Fig. 6A As shown in FIG. 1 , an organic compound film 103Gf which will later become an EL layer 103G is formed.

[0356] The organic compound film 103Gf can be formed using the same method as that which can be used for forming the organic compound film 103Rf. In addition, the organic compound film 103Gf can have the same structure as that of the organic compound film 103Rf.

[0357] Then, if Fig. 6A As shown, a sacrificial film 158Gf and a mask film 159Gf are sequentially formed. Then, a resist mask 190G is formed. The materials and forming methods of the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and forming methods of the resist mask 190G are the same as those applicable to the resist mask 190R.

[0358] The resist mask 190G is provided at a position overlapping with the conductive layer 152G.

[0359] Then, if Figure 6B As shown, a portion 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 portion of the sacrificial film 158Gf is removed, thereby forming a sacrificial layer 158G. Next, the organic compound film 103Gf is processed to form the EL layer 103G.

[0360] Then, if Figure 6C As shown, an organic compound film 103Bf is formed.

[0361] The organic compound film 103Bf can be formed using the same method as that which can be used for forming the organic compound film 103Rf. In addition, the organic compound film 103Bf can have the same structure as that of the organic compound film 103Rf.

[0362] Then, if Figure 6C As shown, a sacrificial film 158Bf and a mask film 159Bf are sequentially formed. Then, a resist mask 190B is formed. The materials and forming methods of the sacrificial film 158Bf and the mask film 159Bf are the same as those that can be used for the sacrificial film 158Rf and the mask film 159Rf. The materials and forming methods of the resist mask 190B are the same as those that can be used for the resist mask 190R.

[0363] The resist mask 190B is provided at a position overlapping with the conductive layer 152B.

[0364] Then, if Fig.6D As shown, a portion of the mask film 159Bf is removed using the resist mask 190B, thereby forming the 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 portion of the sacrificial film 158Bf is removed, thereby forming the sacrificial layer 158B. Next, the organic compound film 103Bf is processed to form the EL layer 103B. For example, using the mask layer 159B and the sacrificial layer 158B as a hard mask, a portion of the organic compound film 103Bf is removed, thereby forming the EL layer 103B.

[0365] Therefore, if Fig.6D As shown, the stacked structure of the EL layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. In addition, the mask layer 159R and the mask layer 159G are exposed.

[0366] Note that the side surfaces of the EL layer 103R, the EL layer 103G, and the EL layer 103B are preferably perpendicular or substantially perpendicular to the surface on which they are formed. For example, the angle formed by the surface on which they are formed and these side surfaces is preferably not less than 60 degrees and not more than 90 degrees.

[0367] As described above, the distance between two adjacent EL layers among the EL layer 103R, the EL layer 103G, and the EL layer 103B formed using the photolithography method can be reduced to less than 8 μm, less than 5 μm, less than 3 μm, less than 2 μm, or less than 1 μm. Here, for example, the distance can be specified based on the distance between the opposite ends of two adjacent EL layers among the EL layer 103R, the EL layer 103G, and the EL layer 103B. In this way, by reducing the distance between the island-shaped EL layers, a display device with high definition 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 less than 10 μm, less than 8 μm, less than 5 μm, less than 3 μm, or less than 2 μm. In addition, the distance between the first electrodes of adjacent light-emitting devices is preferably greater than 2 μm and less than 5 μm.

[0368] Then, if Fig. 7A As shown, mask layer 159R, mask layer 159G and mask layer 159B are preferably removed.

[0369] The mask layer removal step can be performed by the same method as the mask layer processing step. In particular, wet etching can reduce damage to the EL layer 103 when the mask layer is removed, compared with dry etching.

[0370] Alternatively, the mask film may be removed by dissolving it in a polar solvent such as water or alcohol. Examples of the alcohol include ethanol, methanol, isopropyl alcohol (IPA), and glycerin.

[0371] After removing the mask layer, a drying treatment may be performed to remove surface water. For example, a heat treatment may be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment may be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. By adopting a reduced pressure atmosphere, drying can be performed at a lower temperature, so it is preferred.

[0372] Then, if Figure 7B As shown, an inorganic insulating film 125f is formed.

[0373] Then, if Figure 7C As shown in FIG. 1 , an insulating film 127 f which will later become an insulating layer 127 is formed on the inorganic insulating film 125 f.

[0374] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower.

[0375] As the inorganic insulating film 125f, it is preferable to form an insulating film with a thickness of 3 nm, 5 nm or 10 nm and 200 nm, 150 nm, 100 nm or 50 nm within the above-mentioned substrate temperature range.

[0376] The inorganic insulating film 125f is preferably formed by, for example, the ALD method. The ALD method is preferred because it can reduce deposition damage and deposit a film with high coverage. As the inorganic insulating film 125f, for example, an aluminum oxide film is preferably formed by the ALD method.

[0377] The insulating film 127f is preferably formed by the wet deposition method described above. The insulating film 127f is preferably formed by, for example, a photosensitive material by spin coating, and more specifically, is preferably formed by using a photosensitive resin composition containing an acrylic resin.

[0378] Next, exposure is performed to sensitize a portion of the insulating film 127f with visible light or ultraviolet light. The insulating layer 127 is formed in a region sandwiched between any two of the conductive layer 152R, the conductive layer 152G, and the conductive layer 152B and around the conductive layer 152C.

[0379] The width of the insulating layer 127 to be formed later can be controlled by the region in which the insulating film 127f is exposed. In this embodiment, the insulating layer 127 is processed so that the insulating layer 127 has a portion overlapping with the top surface of the conductive layer 151.

[0380] The light used for exposure preferably includes i-line (wavelength: 365 nm). Alternatively, the light used for exposure may include at least one of g-line (wavelength: 436 nm) and h-line (wavelength: 405 nm).

[0381] Then, if Fig. 8A As shown, development is performed to remove the exposed region in the insulating film 127f, thereby forming the insulating layer 127a.

[0382] Then, if Figure 8BAs shown, the insulating layer 127a is used as a mask to perform etching to remove a portion of the inorganic insulating film 125f, thereby reducing the thickness of a portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, the inorganic insulating layer 125 is formed under the insulating layer 127a. In addition, the surface of the thin portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B is exposed. Hereinafter, the etching process using the insulating layer 127a as a mask is sometimes referred to as the first etching process.

[0383] The first etching process can be performed by dry etching or wet etching. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the first etching process can be performed at once, which is preferable.

[0384] When dry etching is performed, chlorine-based gas is preferably used. As the chlorine-based gas, one gas selected from Cl2, BCl3, SiCl4, and CCl4, or a mixture of two or more of the above gases, can be used. In addition, one gas selected from oxygen gas, hydrogen gas, helium gas, and argon gas, or a mixture of two or more of the above gases can be appropriately added to the above chlorine-based gas. By utilizing dry etching, thin regions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can be formed with excellent in-plane uniformity.

[0385] As a dry etching device, a dry etching device having a high-density plasma source can be used. As a dry etching device having a high-density plasma source, for example, an inductively coupled plasma (ICP: Inductively Coupled Plasma) etching device can be used. Alternatively, a capacitively coupled plasma (CCP: Capacitively Coupled Plasma) etching device including parallel plate electrodes can be used.

[0386] In addition, it is preferable to perform the first etching treatment by wet etching. By using the wet etching method, the damage to the EL layer 103R, the EL layer 103G, and the EL layer 103B 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 can be used as an alkaline solution in the wet etching of an aluminum oxide film. In addition, an acidic solution containing a fluoride can also be used. In this case, wet etching can be performed in a glue coating manner. When the inorganic insulating film 125f is deposited using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the above-mentioned etching treatment can be performed at one time, so it is preferable.

[0387] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the etching process is stopped in a state where the thickness is reduced. In this way, by leaving the corresponding sacrificial layers 158R, 158G, and 158B on the EL layers 103R, 103G, and 103B, it is possible to prevent the EL layers 103R, 103G, and 103B from being damaged in the subsequent process.

[0388] Next, the entire substrate is preferably exposed to visible light or ultraviolet light to irradiate the insulating layer 127a. The energy density of this exposure is preferably greater than 0 mJ / cm 2 And 800mJ / cm 2 Below, more preferably greater than 0 mJ / cm 2 And 500mJ / cm 2 By performing such exposure after development, the transparency of the insulating layer 127a can be improved. In addition, the substrate temperature required for heat treatment in a later step for deforming the insulating layer 127a into a tapered shape can be reduced.

[0389] Here, by providing an oxygen blocking insulating layer (for example, an aluminum oxide film) as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, diffusion of oxygen into the EL layer 103R, the EL layer 103G, and the EL layer 103B can be reduced.

[0390] Next, a heat treatment (also called post-baking) is performed. By performing the heat treatment, the insulating layer 127a can be deformed into an insulating layer 127 having a tapered shape on its side. Figure 8C ). The heat treatment is performed at a temperature lower than the heat resistance temperature of the EL layer. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 130°C. 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. Thus, 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.

[0391] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, but the sacrificial layers 158R, 158G, and 158B are left thin, so that the EL layers 103R, 103G, and 103B can be prevented from being damaged and deteriorated during the heat treatment. Thus, the reliability of the light-emitting device can be improved.

[0392] Then, if Fig.9AAs shown in FIG. 1 , the insulating layer 127 is used as a mask to perform etching to remove a portion of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, an opening is formed in each of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surfaces of the EL layer 103R, the EL layer 103G, the EL layer 103B, and the conductive layer 152C are exposed. Note that this etching process may be referred to as a second etching process hereinafter.

[0393] The end of the inorganic insulating layer 125 is covered with the insulating layer 127. Fig.9A An example is shown in which a portion of the end portion of the sacrificial layer 158G (specifically, the tapered portion formed by the first etching process) is covered with the insulating layer 127 and the tapered portion formed by the second etching process is exposed.

[0394] In addition, the second etching process is performed by wet etching. By using the wet etching method, the damage to the EL layer 103R, the EL layer 103G, and the EL layer 103B can be reduced compared with 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 EL layer 103 from dissolving, the wet etching is preferably performed using an aqueous solution.

[0395] Then, if Fig. 9B As shown in FIG. 1 , a common electrode 155 is formed over the EL layer 103R, the EL layer 103G, the EL layer 103B, the conductive layer 152C, and the insulating layer 127. The common electrode 155 can be formed by a method such as a sputtering method or a vacuum evaporation method.

[0396] Then, if Fig. 9C As shown, a protective layer 131 is formed on the common electrode 155. The protective layer 131 can be formed by vacuum evaporation, sputtering, CVD, ALD or the like.

[0397] Next, the substrate 120 is bonded to the protective layer 131 using the resin layer 122, whereby a display device can be manufactured. As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the insulating layer 156 is provided so as to include a region overlapping with the side surface of the conductive layer 151, and the conductive layer 152 is formed so as to cover the conductive layer 151 and the insulating layer 156. Thus, the yield of the display device can be improved, and the occurrence of defects can be suppressed.

[0398] As described above, in a method for manufacturing a display device of one type of the present invention, the island-shaped EL layer 103R, the island-shaped EL layer 103G, and the island-shaped EL layer 103B are not formed using a high-precision metal mask but are formed by depositing a film on one surface and then processing it, so the island layer can be formed with a uniform thickness. In addition, a high-definition display device or a display device with a high aperture ratio can be realized. In addition, even if the clarity or aperture ratio is high and the distance between sub-pixels is extremely short, the EL layer 103R, the EL layer 103G, and the EL layer 103B can be prevented from contacting each other in adjacent sub-pixels. Therefore, leakage current can be suppressed between sub-pixels. Thus, crosstalk can be prevented to realize a display device with extremely high contrast. In addition, even a display device including a series-type light-emitting device manufactured by photolithography can provide a display device with good characteristics.

[0399] Implementation 4 In this embodiment, a display device which is one embodiment of the present invention is described.

[0400] The display device of this embodiment can be a high-definition display device. Therefore, for example, the display device of this embodiment can be used as a display unit of information terminal devices (wearable devices) such as watch-type and bracelet-type devices, and a display unit of wearable devices that can be worn on the head such as VR devices such as head-mounted displays (HMDs) and glasses-type AR devices.

[0401] In addition, the display device of this embodiment can be a high-resolution display device or a large display device. Therefore, for example, the display device of this embodiment can be used as a display portion of the following devices: electronic devices with large screens such as television devices, desktop or notebook personal computers, displays for computers, etc., digital signage and large game machines such as pinball machines, etc.; digital cameras; digital video cameras; digital photo frames; mobile phones; portable game consoles; portable information terminals; and sound reproduction devices.

[0402] [Display module] Fig. 10A 2 is a perspective view of a 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 may be any of the display device 100B and the display device 100E to be described later.

[0403] The display module 280 includes a substrate 291 and a substrate 292. The display module 280 includes a display portion 281. The display portion 281 is an image display region in the display module 280, and light from each pixel provided in a pixel portion 284 described below can be viewed.

[0404] Fig. 10B2 is a perspective view of a structure on one side of a substrate 291. A circuit portion 282, a pixel circuit portion 283 on the circuit portion 282, and a pixel portion 284 on the pixel circuit portion 283 are stacked on the substrate 291. In addition, a terminal portion 285 for connecting to the FPC 290 is provided on a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 is electrically connected to the circuit portion 282 via a wiring portion 286 composed of a plurality of wirings.

[0405] The pixel portion 284 includes a plurality of pixels 284 a arranged periodically. Fig. 10B An enlarged view of one pixel 284a is shown on the right side of FIG. The pixel 284a can adopt the various structures described in the above embodiment. Fig. 10B Pixel 284a is shown having Figure 3A An example of a case where the pixel 178 shown has the same structure.

[0406] The pixel circuit portion 283 includes a plurality of pixel circuits 283 a arranged periodically.

[0407] One pixel circuit 283a controls driving of a plurality of elements included in one pixel 284a.

[0408] The circuit unit 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit unit 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 include at least one of a calculation circuit, a storage circuit, and a power supply circuit.

[0409] The FPC 290 is used as wiring for supplying video signals, power supply potential, and the like from the outside to the circuit portion 282. Alternatively, an IC may be mounted on the FPC 290.

[0410] The display module 280 may have a structure in which one or both of the pixel circuit portion 283 and the circuit portion 282 are stacked on the lower side of the pixel portion 284 , so that the display portion 281 may have an extremely high aperture ratio (effective display area ratio).

[0411] This high-definition display module 280 is suitable for use in VR devices such as HMD or glasses-type AR devices. For example, because the display module 280 has a very high-definition display unit 281, in a structure where the display unit of the display module 280 is viewed through a lens, the user will not see the pixels even if the display unit is magnified by the lens, thereby achieving a highly immersive display. In addition, the display module 280 can also be applied to electronic devices with a relatively small display unit.

[0412] [Display device 100A] Fig.11AThe display device 100A shown includes a substrate 301 , a light emitting device 130R, a light emitting device 130G, a light emitting device 130B, a capacitor 240 , and a transistor 310 .

[0413] Substrate 301 is equivalent to Fig. 10A and Fig. 10B 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 crystal silicon substrate can be used. The transistor 310 includes a portion 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 doped with impurities in the substrate 301 and is used as a source or a drain. The insulating layer 314 covers the side of the conductive layer 311.

[0414] Furthermore, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0415] In addition, an insulating layer 261 is provided to cover the transistor 310 , and the capacitor 240 is provided over the insulating layer 261 .

[0416] Capacitor 240 includes conductive layer 241, conductive layer 245, and insulating layer 243 therebetween. Conductive layer 241 serves as one electrode in capacitor 240, conductive layer 245 serves as the other electrode in capacitor 240, and insulating layer 243 serves as a dielectric of capacitor 240.

[0417] The conductive layer 241 is provided on the insulating layer 261 and embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 through the plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided in a manner covering the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 via the insulating layer 243.

[0418] An insulating layer 255 is provided 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. The light emitting devices 130R, 130G, and 130B are provided on the insulating layer 175. An insulator is provided in a region between adjacent light emitting devices.

[0419] The insulating layer 156R is provided so as to include a region overlapping with the side surface of the conductive layer 151R, the insulating layer 156G is provided so as to include a region overlapping with the side surface of the conductive layer 151G, and the insulating layer 156B is provided so as to include a region overlapping with the side surface of the conductive layer 151B. Furthermore, the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, the conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and the conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. The sacrificial layer 158R is provided on the EL layer 103R, the sacrificial layer 158G is provided on the EL layer 103G, and the sacrificial layer 158B is provided on the EL layer 103B.

[0420] The conductive layers 151R, 151G, and 151B are electrically connected to one of the source and the drain of the transistor 310 via the 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.

[0421] 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. The substrate 120 is bonded to the protective layer 131 by the resin layer 122. The details of the components of the light emitting device 130 to the substrate 120 can be referred to Embodiment 3. The substrate 120 corresponds to Fig. 10A substrate 292.

[0422] Fig. 11B Show Fig.11A A modified example of the display device 100A shown. Fig. 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 a region overlapping one of the coloring layer 132R, the coloring layer 132G, and the coloring layer 132B. Fig. 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.

[0423] [Display device 100B] Fig.12 A perspective view of the display device 100B is shown.

[0424] The display device 100B has a structure in which a substrate 352 and a substrate 351 are bonded together. Fig.12 In FIG. 3 , the substrate 352 is indicated by a dotted line.

[0425] The display device 100B includes a pixel portion 177 , a connection portion 140 , a circuit 356 , a wiring 355 , and the like. Fig.12 FIG. 1 shows an example in which the display device 100B is equipped with the IC 354 and the FPC 353. Fig.12 The structure shown is called a display module including the display device 100B, IC (integrated circuit) and FPC. Here, the substrate of the display device with a connector such as FPC mounted thereon or the substrate with IC mounted thereon is called a display module.

[0426] The connection part 140 is disposed outside the pixel part 177. There may be one or more connection parts 140. In the connection part 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.

[0427] As the circuit 356, for example, a scan line driver circuit can be used.

[0428] The wiring 355 has a function of supplying a signal and power to the pixel portion 177 and the circuit 356. The signal and power are input to the wiring 355 from the outside through the FPC 353 or are input to the wiring 355 from the IC 354.

[0429] Fig.12 An example of providing IC354 on substrate 351 by COG (Chip On Glass) method or COF (Chip on Film) method is shown. As IC354, for example, an IC including a scanning 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 an FPC by using a COF method.

[0430] Fig.13 An example of a cross section of a portion of the region including the FPC 353 , a portion of the circuit 356 , a portion of the pixel portion 177 , a portion of the connection portion 140 , and a portion of the region including the end portion of the display device 100B is shown.

[0431] [Display device 100C] Fig.13 The display device 100C shown 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, a light-emitting device 130B that emits blue light, and the like between a substrate 351 and a substrate 352 .

[0432] The details of the light emitting device 130R, the light emitting device 130G, and the light emitting device 130B may be referred to Embodiment 1 and Embodiment 2.

[0433] 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.

[0434] 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. An end of the conductive layer 151R is located outside an end of the conductive layer 224R. The insulating layer 156R is provided so as to include a region in contact with a side surface of the conductive layer 151R, and the conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R.

[0435] The conductive layer 224G, conductive layer 151G, conductive layer 152G, and insulating layer 156G in the light-emitting device 130G and the conductive layer 224B, conductive layer 151B, conductive layer 152B, and insulating layer 156B in the light-emitting device 130B are the same as the conductive layer 224R, conductive layer 151R, conductive layer 152R, and insulating layer 156R in the light-emitting device 130R, so detailed description is omitted.

[0436] Concave portions are formed in conductive layer 224R, conductive layer 224G, and conductive layer 224B so as to cover the openings provided in insulating layer 214. The concave portions are filled with layer 128.

[0437] The layer 128 has the function of flattening the concave portions of the conductive layers 224R, 224G, and 224B. The conductive layers 151R, 151G, and 151B electrically connected to the conductive layers 224R, 224G, and 224B are provided on the conductive layers 224R, 224G, and 224B, and the layer 128. Therefore, the region overlapping the concave portions of the conductive layers 224R, 224G, and 224B can also be used as a light-emitting region, and the aperture ratio of the pixel can be increased.

[0438] Layer 128 may be an insulating layer or a conductive layer. Layer 128 may be formed of various inorganic insulating materials, organic insulating materials, and conductive materials as appropriate. In particular, layer 128 is preferably formed of an insulating material, and more preferably formed of an organic insulating material. Layer 128 may be formed of, for example, the organic insulating material that can be used for insulating layer 127.

[0439] A protective layer 131 is provided on the light emitting device 130R, the light emitting device 130G and the light emitting device 130B. The protective layer 131 and the substrate 352 are bonded by an adhesive layer 142. The substrate 352 is provided with a light shielding layer 157. The sealing of the light emitting device 130 may adopt a solid sealing structure or a hollow sealing structure. Fig.13 In the embodiment, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, that is, a solid sealing structure is adopted. Alternatively, the space may be filled with an inert gas (nitrogen or argon, etc.), that is, a hollow sealing structure is adopted. In this case, the adhesive layer 142 may also be arranged in a manner that does not overlap with the light-emitting device. In addition, a resin different from the adhesive layer 142 arranged in a frame shape may be used to fill the space.

[0440] Fig.13 The following example is shown: the connection portion 140 includes a conductive layer 224C processed from the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive layer 151C processed from the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive layer 152C processed from the same conductive film as the conductive layers 152R, 152G, and 152B. In addition, Fig.13 An example is shown in which the insulating layer 156C is provided so as to include a region overlapping with the side surface of the conductive layer 151C.

[0441] The display device 100B is a top emission type display device. The light emitting device emits light to the substrate 352 side. The substrate 352 preferably uses a material with high transmittance to visible light. When the light emitting device emits infrared light or near-infrared light, it is preferably used a material with high transmittance to them. The pixel electrode includes a material that reflects visible light, and the counter electrode (common electrode 155) includes a material that transmits visible light.

[0442] 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 portion of the insulating layer 211 is used as a gate insulating layer of each transistor. A portion of the insulating layer 213 is used as a gate insulating layer of each transistor. The insulating layer 215 is provided in a manner covering the transistor. The insulating layer 214 is provided in a manner covering the transistor and is used 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 transistor, and it can be one or more than two.

[0443] As the insulating layer 211 , the insulating layer 213 , and the insulating layer 215 , an inorganic insulating film is preferably used.

[0444] As the insulating layer 214 serving as a planarizing layer, an organic insulating layer is preferably used.

[0445] The transistor 201 and the transistor 205 include: a conductive layer 221 used as a gate; an insulating layer 211 used as a gate insulating layer; a conductive layer 222a and a conductive layer 222b used as a source and a drain; a semiconductor layer 231; an insulating layer 213 used as a gate insulating layer; and a conductive layer 223 used as a gate.

[0446] A connection portion 204 is provided in a region of the substrate 351 that is not overlapped by the substrate 352. In the connection portion 204, the source electrode or the drain electrode of the transistor 202 is electrically connected to the FPC 372 through the conductive layer 166 and the connection layer 242. The following example is shown: the conductive layer 166 has a laminated structure of a conductive film obtained by processing the same conductive film as the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, a conductive film obtained by processing the same conductive film as the conductive layer 151R, the conductive layer 151G, and the conductive layer 151B, and a conductive film obtained by processing the same conductive film as the conductive layer 152R, the conductive layer 152G, and the conductive layer 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.

[0447] It is preferable to provide a light shielding layer 157 on the surface of the substrate 352 on the substrate 351 side. The light shielding layer 157 may be provided between adjacent light emitting devices, in the connection portion 140 and the circuit 356, etc. In addition, various optical members may be arranged outside the substrate 352.

[0448] The substrate 351 and the substrate 352 can each adopt a material that can be used for the substrate 120 .

[0449] As the adhesive layer 142 , a material that can be used for the resin layer 122 can be used.

[0450] As the connection layer 242 , an anisotropic conductive film (ACF: Anisotropic Conductive Film), anisotropic conductive paste (ACP: Anisotropic Conductive Paste), or the like can be used.

[0451] [Display device 100D] Fig.14 The display device 100D shown in FIG. Fig.13 The main difference of the display device 100C shown is that the display device 100D is a bottom emission type display device.

[0452] Light emitted by the light emitting device is emitted to the side of the substrate 351. It is preferable to use a material having high transmittance to visible light for the substrate 351. On the other hand, there is no limitation on the transmittance of the material used for the substrate 352.

[0453] A light shielding layer is preferably formed between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205 . Fig.14 An example is shown in which a light-shielding layer is provided over a substrate 351 , an insulating layer 153 is provided over the light-shielding layer, and transistors 201 , 205 , and the like are provided over the insulating layer 153 .

[0454] 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.

[0455] 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.

[0456] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are all made of a material having high transmittance to visible light. The common electrode 155 is preferably made of a material that reflects visible light.

[0457] Note that although Fig.14 Although the light emitting device 130G is not shown in the figure, the light emitting device 130G is also provided.

[0458] in addition, Fig.14 The example in which the top surface of the layer 128 has a flat portion is shown, but the shape of the layer 128 is not particularly limited.

[0459] [Display device 100D2] The display device 100D2 shown in FIG. 23 is Fig.14 The display device 100D2 is an example of a bottom emission type display device different from the display device 100D shown in the figure. The display device 100D2 is different from the display device 100D in that it includes an organic resin layer 180. Fig.14 The same components are denoted by reference numerals. Fig.14 Records of.

[0460] in addition, Fig. 23B FIG. 2 shows a top view layout of a pixel 178 (a pixel 178 a and a pixel 178 b ) including sub-pixels 110 (sub-pixels 110R, 110G, 110B, and 110W). Fig.23C The top view of the organic resin layer 180 in the region where the sub-pixel 110R and the sub-pixel 110W included in the pixel 178 are formed is shown. The width 110Rw of the light emitting region of the sub-pixel 110R is defined between the light shielding layers 317 .

[0461] like Fig.23A As shown, the organic resin layer 180 is disposed on the insulating layer 214. Fig.23AThe area enclosed by the dotted line and Fig.23C As shown, the organic resin layer 180 includes a concave portion 181 (concave portion 181a, concave portion 181b) having a curved surface at least in the region where the sub-pixel is formed. In addition, the concave portion 181 can also be arranged outside the light-emitting region like the concave portion 181c. By providing the concave portion 181c, the light 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-emitting efficiency.

[0462] A plurality of recesses 181 may be formed in a matrix. The recesses 181a and 181b may be provided in contact with each other or with a plane therebetween.

[0463] 23 shows that the top surface shape of the concave portion is a hexagon ( Fig.23C ), the cross-sectional shape is semicircular ( Fig.23A ) example, other shapes can also be adopted as needed. For example, the top surface shape of the concave portion can also be a triangle, a quadrilateral (including a rectangle and a square), a pentagon or other polygons, the above-mentioned polygons with rounded corners, an ellipse or a circle, etc.

[0464] The organic resin layer 180 may be an insulating layer containing an organic material. For example, the organic resin layer 180 may be made of acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimide amide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenolic resin, and precursors of the above resins. In addition, the organic resin layer 180 may also be made of organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinyl pyrrolidone, polyethylene glycol, polyglycerol, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin.

[0465] In addition, a photosensitive resin may be used for the organic resin layer 180. The photosensitive resin may be a photoresist. The photosensitive resin may be a positive type material or a negative type material.

[0466] The organic resin layer 180 may include a material that absorbs visible light. For example, the organic resin layer 180 itself may be composed of a material that absorbs visible light, or the organic resin layer 180 may include a pigment that absorbs visible light. The organic resin layer 180 may use, for example, 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.

[0467] Furthermore, the first electrode 101 (the first electrode 101R and the first electrode 101W) is provided on the organic resin layer 180 , and the EL layer 103 is provided on the first electrode 101 . The ends of the first electrode 101 and the EL layer 103 may be covered with the insulating layer 127 .

[0468] In addition, the first electrode 101 formed on the organic resin layer 180 also has a recessed portion along the recessed portion of the organic resin layer 180. In addition, the EL layer 103 formed on the first electrode 101 also has a recessed portion along the recessed portion of the first electrode 101. In addition, the common layer 104 formed on the EL layer 103 also has a recessed portion along the recessed portion of the EL layer 103. In addition, the second electrode 102 formed on the common layer 104 also has a recessed portion along the recessed portion of the common layer 104. That is, the recessed portions of the organic resin layer 180, the first electrode 101, the EL layer 103, the common layer 104, and the second electrode 102 have a structure that overlaps with each other.

[0469] The common layer 104 is provided on the EL layer 103 and the insulating layer 127, and the second electrode 102 is provided on the common layer 104. The protective layer 131 is provided on the second electrode 102 and is bonded to the substrate 352 via the adhesive layer 142.

[0470] In addition, although the light emitting device 130G and the light emitting device 130B are not shown in FIG. 23 , the light emitting device 130G and the light emitting device 130B are provided.

[0471] Since the light-emitting device of one embodiment of the present invention including the organic resin layer 180 includes the electron injection layer as described in Embodiment 1, an organic semiconductor device with excellent reliability, low driving voltage, and low power consumption can be provided.

[0472] [Display device 100E] Fig.15 The display device 100E shown is Fig.13 In the variation example of the display device 100C shown, the display device 100E is different from the display device 100C mainly in that the display device 100E includes a coloring layer 132R, a coloring layer 132G, and a coloring layer 132B.

[0473] In the display device 100E, the light emitting device 130 has a region 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 a surface of the substrate 352 on the substrate 351 side. An end portion of the coloring layer 132R, an end portion of the coloring layer 132G, and an end portion of the coloring layer 132B may overlap the light shielding layer 157.

[0474] In the display device 100E, the light emitting device 130 may emit white light, for example. In addition, 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.

[0475] Figures 13 to 15 The example in which the top surface of the layer 128 has a flat portion is shown, but the shape of the layer 128 is not particularly limited.

[0476] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0477] [Display device 100E2] The display device 100E2 shown in FIG. 24 is Fig.15 In the modified example of the display device 100E shown in FIG. 1 , the colored layer 132R, the colored layer 132G, and the colored layer 132B have micro lenses 182. Fig.15 For the same components, please refer to Fig.15 Records of.

[0478] in addition, Fig. 24B FIG. 2 shows a top view layout of a pixel 178 (a pixel 178 a and a pixel 178 b ) including sub-pixels 110 (sub-pixels 110R, 110G, and 110B). Fig.24C The top view shows the microlens 182 in the region where the sub-pixel 110R and the sub-pixel 110G included in the pixel 178 are formed. In the sub-pixel 110G, the region where the common electrode 155 and the EL layer 103 are in contact is the width 110Gw of the light emitting region.

[0479] Fig.24A In the display device 100E2 shown, a planarization film 143 is provided on the protective layer 131, and the coloring layers 132R, 132G, and 132B are provided on the planarization film 144. The planarization film 144 is provided so as to cover the coloring layers 132R, 132G, and 132B. A microlens 182 is provided on the planarization film 144.

[0480] In addition, if Fig.24C As shown, a microlens 182 may be provided in each sub-pixel in a region where the sub-pixel is formed.

[0481] in addition, Fig.24CThe top surface of the microlens 182 is shown as an example of a hexagonal shape, and other shapes can also be used as needed. For example, the top surface of the concave portion can also be a polygon such as a triangle, a quadrilateral (including a rectangle and a square), a pentagon, the above polygons with rounded corners, an ellipse or a circle.

[0482] The microlens 182 may be formed using the same material as the organic resin layer 180 .

[0483] Since the light-emitting device of one embodiment of the present invention having the above-mentioned microlens 182 includes the organic EL device having the electron injection layer described in Embodiment 1, an organic semiconductor device suitable for mobile displays having good reliability, low driving voltage, and low power consumption can be provided.

[0484] Implementation method 5 In this embodiment, an electronic device which is one embodiment of the present invention is described.

[0485] The electronic device of this embodiment includes a display device of one embodiment of the present invention in a display unit. The display device of one embodiment of the present invention has high display performance and can easily achieve high definition and high resolution. Therefore, it can be used in the display unit of various electronic devices.

[0486] Electronic devices include, for example, television sets, desktop or notebook personal computers, displays for computers, etc., digital signage, large-scale game consoles such as pinball machines, and other electronic devices with larger screens, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, portable information terminals, sound reproduction devices, and the like.

[0487] In particular, since the display device of one embodiment of the present invention can improve the clarity, it can be suitably used in electronic devices including a smaller display unit. 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, glasses-type AR devices, and MR devices.

[0488] The electronic device of this embodiment may also include a sensor (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared).

[0489] Reference FIG. 16A to FIG. 16D An example of a wearable device that can be worn on the head is described.

[0490] Fig.16A The electronic device 700A shown and Fig. 16B The electronic devices 700B shown include a pair of display panels 751, a pair of housings 721, a communication unit (not shown), a pair of mounting units 723, a control unit (not shown), an imaging unit (not shown), a pair of optical components 753, a frame 757 and a pair of nose pads 758.

[0491] The display device of one embodiment of the present invention can be applied to the display panel 751. Thus, a highly reliable electronic device can be realized.

[0492] Both electronic devices 700A and 700B can project the image displayed by display panel 751 onto display region 756 in optical member 753. Since optical member 753 is light-transmissive, the user can see the image displayed on the display region superimposed on the transmitted image seen through optical member 753.

[0493] The electronic device 700A and the electronic device 700B may also be provided with a camera capable of photographing the front as an imaging unit. In addition, by providing an acceleration sensor such as a gyro sensor on the electronic device 700A and the electronic device 700B, the user's head orientation can be detected and an image corresponding to the direction can be displayed on the display area 756.

[0494] The communication unit includes a wireless communication device, through which, for example, a video signal can be supplied. In addition, the communication unit may include a connector to which a cable for supplying the video signal and the power supply potential can be connected, instead of or in addition to the wireless communication device.

[0495] Furthermore, electronic device 700A and electronic device 700B are provided with batteries, and can be charged wirelessly or by wire, or both.

[0496] The housing 721 may also be provided with a touch sensor module.

[0497] As the touch sensor module, various touch sensors can be used. For example, various methods such as electrostatic capacitance, resistance film, infrared, electromagnetic induction, surface acoustic wave, and optical can be used. In particular, it is preferred to use electrostatic capacitance or optical sensors in the touch sensor module.

[0498] Fig. 16C The electronic device 800A shown and Fig.16D The electronic devices 800B shown each include a pair of display portions 820 , a housing 821 , a communication portion 822 , a pair of mounting portions 823 , a control portion 824 , a pair of imaging portions 825 , and a pair of lenses 832 .

[0499] The display device of one embodiment of the present invention can be applied to the display portion 820. Thus, an electronic device with high reliability can be realized.

[0500] The display unit 820 is provided at a position visible through the lens 832 inside the housing 821. In addition, by displaying different images on each of the pair of display units 820, three-dimensional display using parallax can be performed.

[0501] The electronic device 800A and the electronic device 800B preferably have a mechanism that can adjust the left and right positions of the lens 832 and the display unit 820 so that the lens 832 and the display unit 820 are located at the most appropriate positions according to the position of the user's eyes.

[0502] The user can use the mounting portion 823 to mount the electronic device 800A or the electronic device 800B on the head.

[0503] 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 be provided to be able to correspond to various viewing angles such as telephoto and wide angle.

[0504] The electronic device 800A may also include a vibration mechanism for use as a bone conduction headset.

[0505] Electronic device 800A and electronic device 800B may both include input terminals. Cables for supplying video signals from a video output device or the like, power for charging a battery provided in the electronic device, and the like may be connected to the input terminals.

[0506] The electronic device according to one embodiment of the present invention may have a function of wirelessly communicating with the earphone 750 .

[0507] In addition, the electronic device may include an earphone unit. Fig. 16B The electronic device 700B shown includes an earphone unit 727. A part of the wiring connecting the earphone unit 727 and the control unit may be arranged inside the housing 721 or the mounting unit 723.

[0508] same, Fig.16D The electronic device 800B shown includes an earphone unit 827. For example, a structure in which the earphone unit 827 and the control unit 824 are connected in a wired manner may be adopted.

[0509] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type (electronic devices 700A and 700B, etc.) and goggles-type (electronic devices 800A and 800B, etc.) are preferable.

[0510] Fig.17AThe electronic device 6500 shown is a portable information terminal device that can be used as a smartphone.

[0511] The electronic device 6500 includes a housing 6501, a display portion 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 portion 6502 has a touch panel function.

[0512] The display device of one embodiment of the present invention can be used as the display portion 6502. Thus, a highly reliable electronic device can be achieved.

[0513] Fig. 17B 65 is a schematic cross-sectional view of an end portion of a housing 6501 on a side of a microphone 6506 .

[0514] A light-transmitting protective component 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, an optical component 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are provided in the space surrounded by the housing 6501 and the protective component 6510.

[0515] 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).

[0516] In a region outside the display portion 6502, a portion of the display panel 6511 is folded back, and the folded back portion is connected to an FPC 6515. An IC 6516 is mounted on the FPC 6515. The FPC 6515 is connected to a terminal provided on a printed circuit board 6517.

[0517] The display panel 6511 can use a display 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. In addition, by folding a portion of the display panel 6511 to provide a connection portion with the FPC 6515 on the back of the pixel portion, an electronic device with a narrow frame can be realized.

[0518] Fig. 17C An example of a television set is shown. In a television set 7100, a display portion 7000 is incorporated in a housing 7171. Here, a structure in which the housing 7171 is supported by a stand 7173 is shown.

[0519] The display device of one embodiment of the present invention can be used as the display portion 7000. Thus, a highly reliable electronic device can be realized.

[0520] The operation can be performed by using the operating switch provided in the housing 7171 and the remote control operating machine 7151 provided separately. Fig. 17C The operation of television device 7100 is shown.

[0521] Fig.17D 1 shows an example of a notebook personal computer. The notebook personal computer 7200 includes a housing 7211 , a keyboard 7212 , a pointing device 7213 , an external connection port 7214 , and the like. A display portion 7000 is incorporated in the housing 7211 .

[0522] The display device of one embodiment of the present invention can be used as the display portion 7000. Thus, a highly reliable electronic device can be realized.

[0523] Fig.17E and Fig.17F An example of digital signage is shown.

[0524] Fig.17E The digital signage 7300 shown includes a housing 7301, a display unit 7000, a speaker 7303, etc. In addition, an LED lamp, operation keys (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, etc. may be included.

[0525] Fig.17F The digital signage 7400 is shown to be disposed on a cylindrical pillar 7401. The digital signage 7400 includes a display unit 7000 disposed along a curved surface of the pillar 7401.

[0526] exist Fig.17E and Fig.17F In this embodiment, the display device of one embodiment of the present invention can be used for the display portion 7000. Thus, a highly reliable electronic device can be achieved.

[0527] The larger the display unit 7000 is, the more information can be provided at one time. The larger the display unit 7000 is, the easier it is to attract people's attention, for example, the advertising effect can be improved.

[0528] like Fig.17E and Fig.17F As shown, the digital signage 7300 or the digital signage 7400 can preferably be linked with the information terminal device 7311 or the information terminal device 7411 such as a smart phone carried by the user through wireless communication.

[0529] FIG. 18A to FIG. 18GThe electronic device shown includes a housing 9000, a display portion 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connecting terminal 9006, a sensor 9007 (the sensor has the function of measuring the following factors: force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, electricity, radiation, flow, humidity, inclination, vibration, smell or infrared), a microphone 9008, etc.

[0530] FIG. 18A to FIG. 18G The electronic device shown has various functions. For example, it may have the following functions: a function of displaying various information (static images, dynamic images, text images, etc.) on a display unit; a function of a touch panel; a function of displaying a calendar, date, or time, etc.; a function of controlling processing by using various software (programs); a function of wireless communication; a function of reading out programs or data stored in a storage medium and processing them; etc.

[0531] Below, we explain in detail FIG. 18A to FIG. 18G Electronic equipment shown.

[0532] Fig.18A 9171 is a perspective view showing a portable information terminal 9171. The portable information terminal 9171 can be used as a smart phone, for example. Note that a speaker 9003, a connection terminal 9006, a sensor 9007, and the like can also be provided in the portable information terminal 9171. In addition, as the portable information terminal 9171, text or image information can be displayed on multiple surfaces. Fig.18A 9050. In addition, information 9051 indicated by a dotted rectangle may be displayed on another surface of the display unit 9001. Examples of information 9051 include information indicating that an email, SNS, or phone call has been received; a title of the email or SNS; a sender's name of the email or SNS; a date; a time; a remaining battery level; and radio wave strength. Alternatively, icon 9050 may be displayed at a location where information 9051 is displayed.

[0533] Fig.18B 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 information 9052, information 9053, and information 9054 are displayed on different surfaces. For example, when the portable information terminal 9172 is placed in a jacket pocket, the user can check the information 9053 displayed at a position viewed from above the portable information terminal 9172.

[0534] Fig.18C9173 is a perspective view showing a tablet terminal 9173. The tablet terminal 9173 can execute various application software such as mobile phone, reading and editing of e-mails and articles, playing music, network communication, computer games, etc. The tablet terminal 9173 includes a display portion 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front of the housing 9000, an operation key 9005 used as an operation button on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0535] Fig.18D 9001 is a stereoscopic diagram showing a watch-type portable information terminal 9200. The portable information terminal 9200 can be used, for example, as a smart watch (registered trademark). In addition, the display surface of the display unit 9001 is curved, and a display can be performed along its curved display surface. In addition, the portable information terminal 9200 can perform hands-free calls, for example, by communicating with a headset capable of wireless communication. In addition, by using the connection terminal 9006, the portable information terminal 9200 can perform data transmission or charging with other information terminals. Charging can also be performed by wireless power supply.

[0536] FIG. 18E to FIG. 18G 9201 is a perspective view showing a foldable portable information terminal. Fig.18E is a perspective view of the portable information terminal 9201 in an unfolded state. Figure 18G This is a three-dimensional diagram of the folded state. Fig.18F is from Fig.18E Status and Figure 18G The portable information terminal 9201 is easy to carry in the folded state, and has a large display area that is seamlessly spliced ​​in the unfolded state, so the display is easy to browse. The display unit 9001 included in the portable information terminal 9201 is supported by three housings 9000 connected by hinges 9055. The display unit 9001 can be bent within a range of a curvature radius of 0.1 mm or more and 150 mm or less, for example.

[0537] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate. Example 1

[0538] In this example, detailed manufacturing methods and characteristics of light emitting devices 1-1 and 1-2 as light emitting devices of one embodiment of the present invention and comparative light emitting device 1 as a comparative light emitting device are described. The structural formulas of main compounds used in this example are shown below.

[0539] [Chemical formula 7]

[0540] (Method for manufacturing light emitting device 1-1) First, a 100 nm thick silver, palladium and copper alloy (APC: Ag-Pd-Cu) as a reflective electrode and a 50 nm thick indium tin oxide (ITSO) containing silicon oxide as a transparent electrode were deposited in sequence on a glass substrate by sputtering from one side of the substrate to form a first electrode 101 with a size of 2 mm×2 mm. The transparent electrode was used as an anode and was considered as the first electrode 101 in combination with the above-mentioned reflective electrode.

[0541] Next, as a pretreatment for forming a light-emitting device on the substrate, the surface of the substrate was washed with water and baked at 200° C. for 1 hour.

[0542] Then, the substrate is placed inside the chamber and the pressure is reduced to 1×10 -4 Pa in a vacuum evaporation equipment, and vacuum bake at a temperature of 170°C for 30 minutes in a heating chamber in the vacuum evaporation equipment, and then the substrate is cooled for about 30 minutes.

[0543] Next, the substrate is fixed on a bracket provided in a vacuum evaporation device in a manner such that the surface on which the first electrode 101 is formed faces downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as: PCBBiF) represented by the above structural formula (i) and a material having an electron acceptor property and a molecular weight of 672 and containing four or more fluorine atoms (OCHD-003) are co-evaporated on the first electrode 101 by a evaporation method in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and a thickness of 10 nm, thereby forming a hole injection layer 111.

[0544] PCBBiF was evaporated on the hole injection layer 111 to a thickness of 100 nm to form a hole transport layer.

[0545] Next, on the first hole transport layer, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP) represented by the above structural formula (iii) and [2-d3-methyl-8-(2- The luminescent layer was formed by co-evaporation in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)) (pyridyl-κN)benzofurano[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC) (abbreviated as: Ir(5mppy-d3)2(mbfpypy-d3)) with a thickness of 40nm.

[0546] Then, 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (v) was evaporated in a thickness of 20 nm, and then 8mpTP-4mDBtPBfpm was evaporated in a thickness of 15 nm to form an electron transport layer.

[0547] After forming the electron transport layer, 8mpTP-4mDBtPBfpm, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as: Pyrrd-Phen) represented by the above structural formula (vi) and indium (In) are co-evaporated in a thickness of 5 nm and a volume ratio of 0.5:0.5:0.02 (=8mpTP-4mDBtPBfpm:Pyrrd-Phen:In) to form an electron injection layer.

[0548] Then, silver (Ag) and magnesium (Mg) are co-evaporated in a volume ratio of 1:0.1 and a thickness of 15 nm to form the second electrode 102. In addition, 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II) represented by the above structural formula (vii) is deposited in a thickness of 70 nm on the second electrode 102 as a cap layer to improve light extraction efficiency.

[0549] Next, in a glove box with a nitrogen atmosphere, a sealing process is performed using a glass substrate in such a way that the light-emitting device is not exposed to the atmosphere (a UV-curing sealing material is applied around the device so that UV is not irradiated on the light-emitting device but only on the sealing material, and heat treatment is performed at 80°C under atmospheric pressure for 1 hour), thereby forming a light-emitting device 1-1.

[0550] (Method for manufacturing light emitting device 1-2) Light-emitting device 1-2 replaces the 8mpTP-4mDBtPBfpm in the electron injection layer of light-emitting device 1-1 with 11-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furano[2,3-b]pyrazine (abbreviated as: 11mDBtBPPnfpr) represented by the above-mentioned structural formula (viii) and forms an electron injection layer by co-evaporation with a thickness of 5 nm and a volume ratio of 11mDBtBPPnfpr, Pyrrd-Phen and indium (In) of 0.5:0.5:0.02 (=11mDBtBPPnfpr:Pyrrd-Phen:In). Other aspects are manufactured in the same manner as light-emitting device 1-1.

[0551] (Manufacturing Method of Comparative Light Emitting Device 1) Comparative light-emitting device 1 replaces 8mpTP-4mDBtPBfpm, Pyrrd-Phen and In in the electron injection layer of light-emitting device 1-1 with 2,2′-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as: mPPhen2P) and lithium oxide (Li2O) represented by the above structural formula (ix), and co-evaporates the electron injection layer in a manner with a thickness of 5 nm and a volume ratio of mPPhen2P to Li2O of 1:0.02 (=mPPhen2P:Li2O). The rest is manufactured in the same manner as light-emitting device 1-1.

[0552] The device structures of the light emitting device 1 - 1 , the light emitting device 1 - 2 , and the comparative light emitting device 1 are shown below.

[0553] [Table 5]

[0554] [Table 6]

[0555] In addition, the LUMO energy levels of the second organic compounds 8mpTP-4mDBtPBfpm and 11mDBtBPPnfpr are -3.01eV and -3.02eV, respectively. In addition, the LUMO energy level of mPPhen2P is -2.71eV. The LUMO energy level of the first organic compound Pyrrd-Phen is -2.55eV. That is, light-emitting device 1-1 and light-emitting device 1-2 are light-emitting devices in which the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by more than 0.20eV, and comparative light-emitting device 1 is a light-emitting device in which the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound and the difference is less than 0.20eV.

[0556] Note that the value of the LUMO level was found by cyclic voltammetry (CV) measurement.

[0557] In cyclic voltammetry (CV) measurements, the oxidation peak potential (E pa ) and reduction peak potential (E pc ) to calculate the value of the LUMO energy level (E). In the measurement, the LUMO energy level was calculated from the potential scan in the negative direction. In addition, the scanning speed in the measurement was 0.1 V / s.

[0558] Specifically, the oxidation peak potential (E pa ) and reduction peak potential (E pc ) to calculate the standard redox potential (E o )(=(E pa +E pc ) / 2), from the potential energy of the reference electrode relative to the vacuum level (E x ) minus the standard redox potential (E o ), from which the LUMO energy level (E) can be calculated respectively (=E x -E o ).

[0559] Note that the above shows the case where a reversible redox wave is obtained. In the case where an irreversible redox wave is obtained, the reduction peak potential (E pc ) plus a certain value (0.1 eV) is assumed to be the oxidation peak potential (E pa ), calculate the standard redox potential (E o ).

[0560] Fig.25 The luminance-current density characteristics of the light emitting device 1-1, the light emitting device 1-2 and the comparative light emitting device 1 are shown. Fig.26 The brightness-voltage characteristics are shown. Fig. 27The current efficiency-current density characteristics are shown. Fig.28 The current density-voltage characteristics are shown. Fig.29 Its electroluminescence spectrum is shown.

[0561] from Figure 25 to Figure 29 It is found that the light-emitting devices 1-1 and 1-2, in which the LUMO level of the second organic compound is at least 0.20 eV lower than the LUMO level of the first organic compound, have lower driving voltages than the comparative light-emitting device 1 and have good characteristics of efficiently emitting green light. Example 2

[0562] In this example, detailed manufacturing methods and characteristics of light emitting devices 2-1 and 2-2 as light emitting devices of one embodiment of the present invention and comparative light emitting devices 2-1 and 2-2 as comparative light emitting devices are described. The structural formulas of main compounds used in this example are shown below.

[0563] [Chemical formula 8]

[0564] (Method for manufacturing light emitting device 2-1) First, a 100 nm thick silver, palladium and copper alloy (APC: Ag-Pd-Cu) as a reflective electrode and a 50 nm thick indium tin oxide (ITSO) containing silicon oxide as a transparent electrode were deposited in sequence on a glass substrate by sputtering from one side of the substrate to form a first electrode 101 with a size of 2 mm×2 mm. The transparent electrode was used as an anode and was considered as the first electrode 101 in combination with the above-mentioned reflective electrode.

[0565] Next, as a pretreatment for forming a light-emitting device on the substrate, the surface of the substrate was washed with water and baked at 200° C. for 1 hour.

[0566] Then, the substrate is placed inside the chamber and the pressure is reduced to 1×10 -4 Pa in a vacuum evaporation equipment, and vacuum bake at a temperature of 170°C for 30 minutes in a heating chamber in the vacuum evaporation equipment, and then the substrate is cooled for about 30 minutes.

[0567] Next, the substrate is fixed on a bracket provided in a vacuum evaporation device in a manner such that the surface on which the first electrode 101 is formed faces downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviated as: PCBBiF) represented by the above structural formula (i) and a material having an electron acceptor property and a molecular weight of 672 and containing four or more fluorine atoms (OCHD-003) are co-evaporated on the first electrode 101 by a evaporation method in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) and a thickness of 10 nm, thereby forming a hole injection layer 111.

[0568] PCBBiF was evaporated on the hole injection layer 111 to a thickness of 100 nm to form a hole transport layer.

[0569] Next, on the first hole transport layer, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviated as 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP) represented by the above structural formula (iii) and [2-d3-methyl-8-(2- The luminescent layer was formed by co-evaporation in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)) (pyridyl-κN)benzofurano[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κC) (abbreviated as: Ir(5mppy-d3)2(mbfpypy-d3)) with a thickness of 40nm.

[0570] Then, 2-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (v) was evaporated in a thickness of 20 nm, and then 8mpTP-4mDBtPBfpm was evaporated in a thickness of 15 nm to form an electron transport layer.

[0571] After forming the electron transport layer, 8mpTP-4mDBtPBfpm, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviated as: Pyrrd-Phen) represented by the above structural formula (vi) and indium oxide (In2O3) are co-evaporated in a thickness of 5 nm and a volume ratio of 0.5:0.5:0.02 (=8mpTP-4mDBtPBfpm:Pyrrd-Phen:In2O3) to form an electron injection layer.

[0572] Then, the substrate formed up to the electron injection layer was taken out from the vacuum evaporation device and exposed to the atmosphere. Then, trimethylaluminum (TMA) was used as a precursor and water vapor was used as an oxidant to form a 30nm thick aluminum oxide film by ALD method, which was used as the first protective layer.

[0573] A molybdenum film of 50 nm was formed on the first protective layer by a sputtering method, and this film was used as a second protective layer.

[0574] After applying a photoresist on the second protective layer, exposure and development were performed to form a 3 μm wide slit at a position 3.5 μm away from the end of the first electrode, thereby making the EL layer correspond to each of the plurality of first electrodes and independent in the electrode.

[0575] Specifically, the developed photoresist is used as a mask, and an etching gas containing carbon tetrafluoride (CF4), oxygen (O2) and helium (He) and an etching gas containing oxygen (O2) are used to process the second protective layer. Then, an alkaline solution containing tetramethylammonium hydroxide (abbreviated as: TMAH) with water as a solvent and an etching gas containing trifluoromethane (CHF3) and helium (He) are used to remove the photoresist and process the first protective layer. Then, an etching gas containing oxygen (O2) is used to process the EL layer (electron injection layer, electron transport layer, light emitting layer, hole transport layer and hole injection layer).

[0576] After the EL layer is processed, the second protective layer is removed using an etching gas containing carbon tetrafluoride (CF4), oxygen (O2) and helium (He), and then the first protective layer is removed using an acidic solution containing a mixed acid of hydrofluoric acid with water as a solvent, exposing the top surface of the electron injection layer. Then, the substrate is placed inside and the pressure is reduced to 1×10 -4 In a vacuum deposition apparatus of about 1.5 Å / min, a heat treatment was performed at 100° C. for 1 hour in a heating chamber in the vacuum deposition apparatus.

[0577] Then, silver (Ag) and magnesium (Mg) are co-evaporated in a volume ratio of 1:0.1 and a thickness of 15 nm to form the second electrode 102. In addition, 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II) represented by the above structural formula (vii) is deposited in a thickness of 70 nm on the second electrode 102 as a cap layer to improve light extraction efficiency.

[0578] Next, in a glove box with a nitrogen atmosphere, a sealing process is performed using a glass substrate in such a way that the light-emitting device is not exposed to the atmosphere (a UV-curing sealing material is applied around the device so that UV is not irradiated on the light-emitting device but only on the sealing material, and heat treatment is performed at 80°C under atmospheric pressure for 1 hour), thereby forming a light-emitting device 2-1.

[0579] (Method for manufacturing light emitting device 2-2) Light-emitting device 2-2 replaces the 8mpTP-4mDBtPBfpm in the electron injection layer of light-emitting device 2-1 with 11-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furano[2,3-b]pyrazine (abbreviated as: 11mDBtBPPnfpr) represented by the above structural formula (viii) and forms an electron injection layer by co-evaporation with a thickness of 5nm and a volume ratio of 11mDBtBPPnfpr, Pyrrd-Phen and indium oxide (In2O3) of 0.5:0.5:0.02 (=11mDBtBPPnfpr:Pyrrd-Phen:In2O3). Other aspects are manufactured in the same manner as light-emitting device 2-1.

[0580] (Manufacturing method of comparative light emitting device 2-1) The comparative light-emitting device 2-1 is manufactured in the same manner as the light-emitting device 2-1 by replacing the 8mpTP-4mDBtPBfpm, Pyrrd-Phen and indium oxide (In2O3) in the electron injection layer of the light-emitting device 2-1 with 2,2′-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviated as: mPPhen2P) and lithium oxide (Li2O) represented by the above structural formula (ix), and co-evaporating the electron injection layer in a manner with a thickness of 5 nm and a volume ratio of mPPhen2P to lithium oxide (Li2O) of 1:0.02 (=mPPhen2P:Li2O).

[0581] (Manufacturing method of comparative light emitting device 2-2) The comparison light-emitting device 2-2 is a device in which the 8mpTP-4mDBtPBfpm, Pyrrd-Phen and indium oxide (In2O3) in the electron injection layer of the light-emitting device 2-1 are replaced with 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as: αN-βNPAnth), Pyrrd-Phen and indium (In) shown in the above structural formula (x), and the electron injection layer is formed by co-evaporation in a manner with a thickness of 5 nm and a volume ratio of αN-βNPAnth, Pyrrd-Phen and indium (In) of 0.5:0.5:0.02 (=αN-βNPAnth:Pyrrd-Phen:In). The rest is manufactured in the same manner as the light-emitting device 2-1.

[0582] The device structures of the light-emitting device 2-1, the light-emitting device 2-2, the comparative light-emitting device 2-1, and the comparative light-emitting device 2-2 are shown below.

[0583] [Table 7]

[0584] [Table 8]

[0585] In addition, the LUMO energy levels of the second organic compounds 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr and αN-βNPAnth are -3.01eV, -3.02eV and -2.74eV, respectively. In addition, the LUMO energy level of mPPhen2P is -2.71eV. The LUMO energy level of the first organic compound Pyrrd-Phen is -2.55eV. In addition, the value of the LUMO energy level is calculated using the method described in Example 1.

[0586] Fig.30 The luminance-current density characteristics of the light emitting device 2-1, the light emitting device 2-2, the comparative light emitting device 2-1 and the comparative light emitting device 2-2 are shown. Fig.31 The brightness-voltage characteristics are shown. Fig.32 The current efficiency-current density characteristics are shown. Fig.33 The current density-voltage characteristics are shown. Fig.34 Note that the luminance and the emission spectrum were measured at room temperature using a spectroradiometer (SR-UL1R manufactured by Topcon Corporation).

[0587] from Figure 30 to Figure 34 It can be seen that the light-emitting devices 2-1 and 2-2 whose LUMO energy level of the second organic compound is at least 0.20 eV lower than the LUMO energy level of the first organic compound have lower driving voltages than the comparative light-emitting devices 2-1 and 2-2 and have good characteristics of efficiently emitting green light.

[0588] In addition, light-emitting devices having the same stacked structure as the light-emitting device 2-1, the light-emitting device 2-2, the comparative light-emitting device 2-1, and the comparative light-emitting device 2-2 without processing the EL layer by photolithography were manufactured, and their current density at 50 mA / cm 2 The voltage difference below. Fig.35 The relationship between the calculated voltage difference and the LUMO energy level of the second organic compound is shown. Fig.35 It can be seen that the light-emitting device whose LUMO energy level of the second organic compound is lower than 2.74 eV can suppress the increase of the driving voltage even after processing by photolithography, and is a light-emitting device with good characteristics. The LUMO energy level of the first organic compound is -2.55 eV, and it can be seen that the light-emitting device whose LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by more than 0.20 eV can suppress the increase of the driving voltage even after processing by photolithography, and is a light-emitting device with good characteristics.

Claims

1. A light emitting device, comprising: a first electrode; a second electrode; as well as EL layer, The EL layer is located between the first electrode and the second electrode. The EL 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 and a second organic compound, The first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, The second organic compound is an organic compound including a second π-electron-deficient heteroaromatic ring having an electron-donating group, Furthermore, the LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by at least 0.20 eV.

2. A light emitting device, the light emitting device being one of a plurality of light emitting devices included in a light emitting device group, the light emitting device group comprising: a first electrode group formed on the first insulating surface; a second electrode group opposite to the first electrode group; as well as an EL layer group located between the first electrode group and the second electrode group, The light emitting device comprises a first electrode, a second electrode and an EL layer. The first electrode is one of the first electrode groups, The first electrode is independent in each of the plurality of light emitting devices, The EL layer is one of the EL layer group, The EL layer is independent in each of the plurality of light emitting devices, The second electrode is a continuous conductive layer shared by the plurality of light emitting devices. The second electrode and the EL layer overlap with the first electrode, The EL 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 and a second organic compound, The first organic compound is an organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, The second organic compound is an organic compound including a second π-electron-deficient heteroaromatic ring having an electron-donating group, The LUMO energy level of the second organic compound is lower than the LUMO energy level of the first organic compound by at least 0.20 eV, Furthermore, a distance between the EL layer in the light-emitting device and the EL layer in another light-emitting device adjacent to the light-emitting device is greater than or equal to 0.5 μm and less than or equal to 5 μm.

3. The light emitting device according to claim 1 or 2, The electron injection layer is a mixed layer including the metal or the metal oxide, the first organic compound, and the second organic compound.

4. The light emitting device according to claim 1 or 2, wherein the electron injection layer has a stacked structure of a first layer including the metal and a second layer including the first organic compound and the second organic compound, And the first layer is closer to the cathode side than the second layer.

5. The light emitting device according to claim 1 or 2, in, 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), a relationship of -0.80≤LUMO2≤LUMO1-0.20 is satisfied.

6. The light emitting device according to claim 1 or 2, The first π-electron-deficient heteroaromatic ring is a heteroaromatic ring containing two or more pyridine rings.

7. The light emitting device according to claim 1 or 2, The first organic compound has a pK a An organic compound having 8 or more carbon atoms.

8. The light emitting device according to claim 1 or 2, The first π-electron-deficient heteroaromatic ring is different from the second π-electron-deficient heteroaromatic ring.

9. The light emitting device according to claim 1 or 2, The second organic compound comprises 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.

10. The light emitting device according to claim 1 or 2, The acidity coefficient pK of the second organic compound is a Less than 4.

11. The light emitting device according to claim 1 or 2, wherein the light-emitting layer comprises a third organic compound, The third organic compound comprises a third π-electron-deficient heteroaromatic ring, And the third π-electron-deficient heteroaromatic ring is the same as the second π-electron-deficient heteroaromatic ring.

12. The light emitting device according to claim 1 or 2, wherein the light-emitting layer comprises a third organic compound, And the third organic compound is the same organic compound as the second organic compound.

13. The light emitting device according to claim 11, further comprising an electron transport layer between the light emitting layer and the electron injection layer, wherein the electron transport layer comprises a fourth organic compound, And the fourth organic compound is an organic compound different from the third organic compound.

14. The light emitting device according to claim 1 or 2, The metal is any metal belonging to Group 3, Group 11 and Group 13 of the Periodic Table of Elements.

15. The light emitting device according to claim 1 or 2, 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.

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