Light-emitting device

Abstract

To provide a light-emitting device that can be applied to high-definition display devices and has a low driving voltage and good current efficiency.SOLUTION: A tandem light-emitting device is fabricated through a photolithography process, and includes a plurality of light-emitting units and an intermediate layer located between the light-emitting units. The intermediate layer has a first region including a metal or a metal oxide, a first organic compound including a first π-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound including a second π-electron-deficient heteroaromatic ring. A LUMO level of the second organic compound is lower than a LUMO level of the first organic compound by greater than or equal to 0.30 eV.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting device, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input / output device (e.g., a touch panel), a driving method thereof, or a manufacturing method thereof. [Background technology]

[0003] Display devices have been developed for various applications in recent years. For example, applications of large display devices include home television devices (also called televisions or television receivers), digital signage, and public information displays (PIDs), while applications of small display devices include smartphones and tablet terminals equipped with touch panels.

[0004] At the same time, there is a demand for display devices with higher resolution. Devices requiring high-resolution display devices include, for example, devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), which are being actively developed.

[0005] As a display element used in a display device, the development of a light-emitting device (also called a light-emitting element) is being actively promoted. A light-emitting device (also called an EL device or an EL element) utilizing the electroluminescence (hereinafter referred to as EL) phenomenon, particularly a light-emitting device mainly using an organic compound, has characteristics such as being easily thin and lightweight, being capable of high-speed response to an input signal, and being capable of being driven by a DC constant voltage power source, and is therefore suitable for a display device.

[0006] In order to obtain a higher-definition light-emitting device using a light-emitting device, research is being conducted on patterning of organic layers by photolithography using photoresist, etc., instead of deposition methods using metal masks. By using photolithography, it is possible to obtain a high-definition display device with an EL layer spacing of several μm (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2018-521459 [Patent Document 2] International Publication No. 2021 / 045178 Summary of the Invention [Problem to be solved by the invention]

[0008] It has long been known that the initial characteristics and reliability of the EL layer of a light-emitting device are affected when it is exposed to atmospheric components such as water and oxygen, and so it has been common knowledge that it should be handled in a near-vacuum atmosphere. In particular, materials with donor properties, such as alkali metals or alkaline earth metals, or compounds of these, are used for the electron injection layer or intermediate layer in a light-emitting device with a tandem structure, but these metals and compounds are highly reactive with water or oxygen, and when the surface of the EL layer is exposed to the atmosphere, they deteriorate in an instant and no longer function as an intermediate layer.

[0009] However, as mentioned above, the photolithography process requires the surface of the EL layer to be exposed to the air, which makes it difficult to obtain good characteristics from light-emitting devices processed by photolithography.

[0010] In particular, when processing is performed by photolithography, an increase in driving voltage often becomes a problem.

[0011] Therefore, an object of one aspect of the present invention is to provide a light-emitting device having a novel tandem structure. Or, an object of another aspect of the present invention is to provide a light-emitting device having a tandem structure with good efficiency. Or, an object of one aspect of the present invention is to provide a light-emitting device having a tandem structure with a low driving voltage. Or, an object of one aspect of the present invention is to provide a light-emitting device having a tandem structure with good reliability. Or, an object of another aspect of the present invention is to provide a light-emitting device having a tandem structure with good efficiency and reliability. Or, an object of another aspect of the present invention is to provide a light-emitting device having a tandem structure with a low driving voltage and good reliability. Or, an object of another aspect of the present invention is to provide a light-emitting device having a tandem structure with a low driving voltage and good efficiency and reliability.

[0012] Alternatively, one embodiment of the present invention has an object to provide a light-emitting device having a novel tandem structure manufactured through a photolithography process. Alternatively, another embodiment of the present invention has an object to provide a light-emitting device having a tandem structure manufactured through a photolithography process and having good efficiency. Alternatively, one embodiment of the present invention has an object to provide a light-emitting device having a tandem structure manufactured through a photolithography process and having a low driving voltage. Alternatively, one embodiment of the present invention has an object to provide a light-emitting device having a tandem structure manufactured through a photolithography process and having good reliability. Alternatively, another embodiment of the present invention has an object to provide a light-emitting device having a tandem structure manufactured through a photolithography process and having good light-emitting efficiency and reliability. Alternatively, another embodiment of the present invention has an object to provide a light-emitting device having a tandem structure manufactured through a photolithography process and having a low driving voltage and good reliability. Another object of another embodiment of the present invention is to provide a light-emitting device having a tandem structure that is manufactured through a photolithography process and has a low driving voltage, good light-emitting efficiency, and reliability.

[0013] Alternatively, an object of one embodiment of the present invention is to provide a light-emitting device having a novel tandem structure that can be used in a high-definition display device. Alternatively, an object of another embodiment of the present invention is to provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has good efficiency. Alternatively, an object of one embodiment of the present invention is to provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has a low driving voltage. Alternatively, an object of one embodiment of the present invention is to provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has good reliability. Alternatively, an object of another embodiment of the present invention is to provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has good emission efficiency and reliability. Alternatively, an object of another embodiment of the present invention is to provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has a low driving voltage and good reliability. Another object of another embodiment of the present invention is to provide a light-emitting device that can be used in a high-definition display device and has a tandem structure with low driving voltage, favorable light-emitting efficiency, and reliability.

[0014] Another embodiment of the present invention has an object to provide a display device with high reliability. Another embodiment of the present invention has an object to provide a display device with low power consumption. Another embodiment of the present invention has an object to provide a high-definition display device. Another embodiment of the present invention has an object to provide a high-definition display device with good reliability. Another embodiment of the present invention has an object to provide a high-definition display device with low power consumption.

[0015] Note that the description of these problems does not preclude the existence of other problems. One embodiment of the present invention does not necessarily have to solve all of these problems. Problems other than these can be extracted from the description of the specification, drawings, and claims. [Means for solving the problem]

[0016] One aspect of the present invention is a light-emitting device among a plurality of light-emitting devices included in a light-emitting device group having a first electrode group formed on the same insulating surface, a second electrode facing the first electrode group, and a first layer group located between the first electrode group and the second electrode, wherein the first electrode group is made of a plurality of first electrodes independent for each of the plurality of light-emitting devices, the first layer group is made of a plurality of first layers independent for each of the plurality of light-emitting devices, and the second electrode is a continuous conductive layer shared by the plurality of light-emitting devices, and the light-emitting device has the first electrode that is one of the first electrode group, a second electrode, and a first layer that is one of the first layer group, and the second electrode and the first layer overlap the first electrode. the first layer has a first light-emitting layer, a second light-emitting layer, and an intermediate layer located between the first light-emitting layer and the second light-emitting layer, the intermediate layer has a first region containing a metal or a metal oxide, a first organic compound, and a second organic compound, the first organic compound is an organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, the second organic compound is an organic compound having a second π-electron-deficient heteroaromatic ring, the LUMO level of the second organic compound is lower by 0.20 eV or more than the LUMO level of the first organic compound, and the distance between the first layer of the light-emitting device and a first layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

[0017] Alternatively, in the above structure, another embodiment of the present invention is a compound in which, when the LUMO level of the first organic compound is LUMO1 (eV), the LUMO level of the second organic compound (LUMO2 (eV)) is LUMO1-0.50≦LUMO2≦LUMO1-0.20 It is a light-emitting device that satisfies the above requirements.

[0018] Alternatively, in the above structure, another embodiment of the present invention is a compound in which, when the LUMO level of the first organic compound is LUMO1 (eV), the LUMO level of the second organic compound (LUMO2 (eV)) is LUMO1-0.50≦LUMO2≦LUMO1-0.30 It is a light-emitting device that satisfies the above requirements.

[0019] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first π-electron-deficient heteroaromatic ring is a heteroaromatic ring including two or more pyridine rings.

[0020] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first organic compound has an acid dissociation constant pKa of 8 or more.

[0021] Another embodiment of the present invention is a light-emitting device having the above structure, in which the second organic compound has a glass transition temperature of 100° C. or higher.

[0022] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different from each other.

[0023] Another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has an azole ring (an imidazole ring, a pyrazole ring, an oxazole ring, or a thiazole ring), a triazole ring, a diazine ring (a pyrazine ring, a pyrimidine ring, or a pyridazine ring), or a triazine ring.

[0024] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, wherein the second organic compound has an acid dissociation constant pKa of less than 4.

[0025] Alternatively, in the above structure, another embodiment of the present invention is a liquid crystal display device in which the second organic compound has a solubility parameter δ of 4.0 MPa or less. 0.5 A light-emitting device having a polarization term δp:

[0026] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, in which the first light-emitting layer is located closer to the first electrode than the second light-emitting layer, the first light-emitting layer contains a third organic compound, the third organic compound contains 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] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, in which the first light-emitting layer is located closer to the first electrode than the second light-emitting layer, the first light-emitting layer contains a third organic compound, and the third organic compound is the same organic compound as the second organic compound.

[0028] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, which includes a first electron-transport layer between the first light-emitting layer and the intermediate layer, and the first electron-transport layer includes a fourth organic compound, which is an organic compound different from the third organic compound.

[0029] Another embodiment of the present invention is a light-emitting device having the above structure, in which the metal is a metal belonging to Group 1, Group 2, Group 3, Group 11, Group 12, or Group 13.

[0030] Another embodiment of the present invention is a light-emitting device having the above structure, in which the metal is a metal belonging to Group 3, Group 11, Group 12, or Group 13.

[0031] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first π-electron-deficient heteroaromatic ring includes a phenanthroline ring.

[0032] Alternatively, 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 and has an electron-donating group at least at one of the 4-position and the 7-position.

[0033] 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.

[0034] Another embodiment of the present invention is a light-emitting device having the above structure, in which the first organic compound has an acid dissociation constant pKa of 8 or more.

[0035] Alternatively, in the above-described structure, the minimum value of the electrostatic potential of the first organic compound is a threshold value of the electron density distribution in atomic units of 0.0004e / a0 3 In the case of -0.085E h A light emitting device comprising:

[0036] Alternatively, another embodiment of the present invention is the above light-emitting device, in which the metal or metal oxide, the first organic compound, and the second organic compound are mixed in the first region.

[0037] Another embodiment of the present invention is the above light-emitting device, in which a layer containing a metal or a metal oxide and a layer in which a first organic compound and a second organic compound are mixed are stacked in the first region.

[0038] Another embodiment of the present invention is a light-emitting device having the above structure, in which the layer containing a metal or a metal oxide is located between the layer in which the first organic compound and the second organic compound are mixed and the second light-emitting layer.

[0039] Alternatively, in the above-described structure, the first region has a spin density of 5×10 16 spins / cm 3 The above is a light emitting device.

[0040] Alternatively, another embodiment of the present invention is a light-emitting device having the above structure, in which the intermediate layer has a second region, the second region is located between the first region and the second electrode, and the second region includes a third organic compound having hole-transporting properties and a first substance having acceptor properties for the third organic compound.

[0041] Another embodiment of the present invention is a light-emitting device having the above structure, further including a third region containing a second substance between the first region and the second region.

[0042] Alternatively, in the above-described structure, the second region has a spin density of 1×10 17 spins / cm 3 The above is a light emitting device.

[0043] Alternatively, in another embodiment of the present invention, in the above structure, the light-emitting device has a second layer, the second layer is a layer shared by a plurality of light-emitting devices, and the second layer is a light-emitting device located between the first layer and the second electrode.

[0044] Another embodiment of the present invention is a display device including the above light-emitting device.

[0045] Another embodiment of the present invention is a display module including the above-described display device and at least one of a connector and an integrated circuit.

[0046] Another embodiment of the present invention is an electronic device including the above-described display module and at least one of a housing, a battery, a camera, a speaker, and a microphone. Effect of the Invention

[0047] According to one embodiment of the present invention, a light-emitting device having a novel tandem structure can be provided. According to one embodiment of the present invention, a light-emitting device having a tandem structure with good efficiency can be provided. According to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage can be provided. According to one embodiment of the present invention, a light-emitting device having a tandem structure with good reliability can be provided. According to one embodiment of the present invention, a light-emitting device having a tandem structure with good efficiency and reliability can be provided. According to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage and good reliability can be provided. According to one embodiment of the present invention, a light-emitting device having a tandem structure with low driving voltage and good efficiency and reliability can be provided.

[0048] Alternatively, one embodiment of the present invention can provide a light-emitting device having a novel tandem structure manufactured through a photolithography process. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having good efficiency. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having a low driving voltage. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having good reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having good luminous efficiency and reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having a low driving voltage and good reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having a low driving voltage and good reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure manufactured through a photolithography process and having a low driving voltage and good luminous efficiency and reliability.

[0049] Alternatively, one embodiment of the present invention can provide a light-emitting device having a novel tandem structure that can be used in a high-definition display device. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has good efficiency. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has a low driving voltage. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has good emission efficiency and reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has a low driving voltage and good reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has a low driving voltage and good emission efficiency and reliability. Alternatively, one embodiment of the present invention can provide a light-emitting device having a tandem structure that can be used in a high-definition display device and has a low driving voltage and good emission efficiency and reliability.

[0050] 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 display device with low power consumption 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 display device with high reliability can be provided. According to one embodiment of the present invention, a high-definition display device with low power consumption can be provided.

[0051] Note that the description of these effects does not preclude the existence of other effects. One embodiment of the present invention does not necessarily have all of these effects. Effects other than these can be extracted from the description in the specification, drawings, and claims. [Brief description of the drawings]

[0052] [Figure 1] FIG. 1 is a diagram illustrating a light emitting device. [Diagram 2] FIG. 2 is a diagram illustrating a light emitting device. [Diagram 3] 3A and 3B are a top view and a cross-sectional view of the light-emitting device. [Figure 4] 4A to 4E are cross-sectional views showing an example of a method for manufacturing a display device. [Diagram 5] 5A to 5D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 6] 6A to 6D are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 7] 7A to 7C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 8] 8A to 8C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 9] 9A to 9C are cross-sectional views showing an example of a method for manufacturing a display device. [Figure 10] 10A and 10B are perspective views showing a configuration example of a display module. [Figure 11] 11A and 11B are cross-sectional views showing a configuration example of a display device. [Figure 12] FIG. 12 is a perspective view showing a configuration example of a display device. [Figure 13] FIG. 13 is a cross-sectional view showing a configuration example of a display device. [Figure 14] FIG. 14 is a cross-sectional view showing a configuration example of a display device. [Figure 15] FIG. 15 is a cross-sectional view showing a configuration example of a display device. [Figure 16] 16A to 16D are diagrams illustrating examples of electronic devices. [Figure 17] 17A to 17F are diagrams illustrating examples of electronic devices. [Figure 18]18A to 18G are diagrams illustrating examples of electronic devices. [Figure 19] 19(A) to 19(C) show the analysis results of the spin density distribution in the ground state of the composite material. [Figure 20] 20(A) and 20(B) show the results of electrostatic potential map analysis of an organic compound in the ground state. [Figure 21] 21(A) to 21(C) show the results of electrostatic potential map analysis of the composite material in the ground state. [Figure 22] FIG. 22 is a graph showing the luminance-current density characteristics of light-emitting devices 1-1 to 1-8. [Diagram 23] FIG. 23 is a diagram showing the luminance-voltage characteristics of light-emitting devices 1-1 to 1-8. [Figure 24] FIG. 24 is a graph showing the current efficiency-current density characteristics of light-emitting devices 1-1 to 1-8. [Diagram 25] FIG. 25 is a graph showing current density-voltage characteristics of light-emitting devices 1-1 to 1-8. [Figure 26] FIG. 26 is a graph showing electroluminescence spectra of light-emitting devices 1-1 to 1-8. [Figure 27] FIG. 27 is a graph showing current density-voltage characteristics of light-emitting devices 1-1 to 1-8. [Figure 28] FIG. 28 is a graph showing the relationship between the voltage and the LUMO level of the second organic compound at a current density of 50 mA / cm 2 in each of light-emitting devices 1-1 to 1-8. [Figure 29] FIG. 29 is a graph showing the luminance-current density characteristics of the light-emitting devices 2-1 to 2-4. [Diagram 30] FIG. 30 is a diagram showing the luminance-voltage characteristics of the light-emitting devices 2-1 to 2-4. [Diagram 31] FIG. 31 is a graph showing the current efficiency-luminance characteristics of the light-emitting devices 2-1 to 2-4. [Diagram 32]FIG. 32 is a graph showing the current density-voltage of the light-emitting devices 2-1 to 2-4. [Diagram 33] FIG. 33 is a graph showing electroluminescence spectra of the light-emitting devices 2-1 to 2-4. [Diagram 34] FIG. 34 is a diagram showing the luminance-current density characteristics of the light-emitting device 3-1 and the light-emitting device 3-2. [Diagram 35] FIG. 35 is a diagram showing the luminance-voltage characteristics of the light-emitting device 3-1 and the light-emitting device 3-2. [Diagram 36] FIG. 36 is a graph showing the current efficiency-current density characteristics of the light-emitting device 3-1 and the light-emitting device 3-2. [Figure 37] FIG. 37 is a diagram showing the current density-voltage characteristics of the light-emitting device 3-1 and the light-emitting device 3-2. [Figure 38] FIG. 38 shows electroluminescence spectra of the light-emitting devices 3-1 and 3-2. [Figure 39] FIG. 39 is a diagram showing the normalized luminance-time change characteristics of the light-emitting device 3-1 and the light-emitting device 3-2. [Diagram 40] FIG. 40 is a graph showing the luminance-current density characteristics of the light-emitting devices 4-1, 4-2, 4-3, and 4-4. [Diagram 41] FIG. 41 is a diagram showing the luminance-voltage characteristics of the light-emitting device 4-1, the light-emitting device 4-2, the light-emitting device 4-3, and the light-emitting device 4-4. [Diagram 42] FIG. 42 is a graph showing the current efficiency-current density characteristics of the light-emitting devices 4-1, 4-2, 4-3, and 4-4. [Diagram 43] FIG. 43 is a diagram showing current density-voltage characteristics of the light-emitting device 4-1, the light-emitting device 4-2, the light-emitting device 4-3, and the light-emitting device 4-4. [Diagram 44] FIG. 44 is a graph showing electroluminescence spectra of light-emitting devices 4-1, 4-2, 4-3, and 4-4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0053] The embodiments will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that the modes and details of the present invention can be modified in various ways without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0054] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-definition metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0055] (Embodiment 1) A tandem light-emitting device having multiple light-emitting units between a pair of electrodes and an intermediate layer that generates electric charge sandwiched between the multiple light-emitting units can achieve higher current efficiency than a normal light-emitting device having only one light-emitting unit between the electrodes.

[0056] The middle layer of the tandem light-emitting device contains a charge generation layer (CGL), which is a layer in which electrons and holes are generated by charge separation when a voltage is applied.

[0057] As the CGL, it is preferable to use a layer (P-type CGL) containing a material having hole-transporting properties and a material having electron acceptor properties for the material having hole-transporting properties, and a layer (N-type CGL) containing a material having electron-transporting properties and a material having electron donor properties for the material having electron-transporting properties, because this makes it easier to inject holes or electrons into each light-emitting unit and reduces the driving voltage.

[0058] This is because holes generated in the P-type CGL are injected into the hole transport layer of the light-emitting unit on the cathode side via the material having hole transport properties of the P-type CGL, and electrons generated in the N-type CGL are injected into the electron transport layer of the light-emitting unit on the anode side via the material having electron transport properties of the N-type CGL, thereby lowering the carrier injection barrier.

[0059] Here, as one of the methods for forming an organic compound film in a predetermined shape at a predetermined position, a vacuum deposition method using a metal mask (mask deposition) is widely used. However, in recent years, as densification and definition have progressed, mask deposition is approaching its limit for further finer definition due to various reasons, such as problems with alignment accuracy and problems with the placement distance between the substrate and the mask.

[0060] On the other hand, photolithography is a processing method that allows for the formation of denser patterns than mask deposition. Furthermore, photolithography is also easy to use for large areas, so research is being conducted on processing organic compound films using photolithography as an alternative to mask deposition. However, processing organic compound films using photolithography has a major problem specific to light-emitting devices.

[0061] It is known that exposure to atmospheric components such as water and oxygen affects the initial characteristics and reliability of light-emitting devices, and it is common sense that such devices should be handled in a near-vacuum atmosphere, as mentioned above.

[0062] Particularly, care must be taken with the electron injection layer of a light-emitting device and the N-type CGL used as an intermediate layer in a light-emitting device having a tandem structure. This is because the electron injection layer and N-type CGL usually use a material having donor properties to the electron transport material, typically an alkali metal or alkaline earth metal, or a compound thereof (hereinafter also referred to as "alkali metal compound, etc."), to generate electrons. These alkali metal compounds, etc., are highly reactive with water or oxygen, and therefore deteriorate in an instant not only when directly exposed to the air, but also when exposed to the air through multiple organic compound layers, and their functions as an electron injection layer and intermediate layer are impaired.

[0063] However, in the process of processing by the photolithography method as described above, it is necessary to expose the surface of the EL layer to the air. Therefore, when processing by the photolithography method is performed, the electron injection property of the electron injection layer and the intermediate layer using the alkali metal compound etc. is greatly reduced. As a result, a light-emitting device having either or both of the electron injection layer and the intermediate layer using the alkali metal compound etc. and processed by the photolithography method has a reduced light-emitting efficiency or an increased driving voltage, making it difficult to obtain good characteristics.

[0064] Regarding this problem, the electron injection layer can be formed after photolithographic processing due to the structure of the EL layer in the light-emitting device (in the case of a so-called forward stack element in which the electron injection layer is formed after the light-emitting layer), and therefore the effect of this problem can be avoided.

[0065] However, in a tandem light-emitting device, when the light-emitting layer in the light-emitting unit on the cathode side is processed by photolithography, the intermediate layer in contact with the anode side of the light-emitting unit is also exposed to the processing. Therefore, it was difficult to obtain good characteristics while processing a tandem light-emitting device using an intermediate layer having an N-type CGL using an alkali metal compound or the like by photolithography.

[0066] Here, the inventors have found that by using a layer containing 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, instead of the conventional N-type CGL in the intermediate layer, it is possible to obtain a tandem-type light-emitting device having good characteristics even after undergoing a photolithography process involving exposure of the EL layer to the atmosphere.

[0067] That is, by providing a region (first region) containing an organic compound (first organic compound) having 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 a metal oxide, instead of a conventional N-type CGL in the intermediate layer, it is possible to obtain a light-emitting device having good characteristics as a tandem-type light-emitting device even after undergoing a photolithography process involving exposure of the EL layer to the atmosphere.

[0068] Furthermore, in one embodiment of the present invention, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound, and is preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.25 eV lower than the LUMO level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.30 eV lower than the LUMO level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.35 eV lower than the LUMO level of the first organic compound, and more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.40 eV lower than the LUMO level of the first organic compound.

[0069] That is, assuming that the LUMO level of the first organic compound is "LUMO1 (eV)" and the LUMO level of the second organic compound is "LUMO2 (eV)", it is preferable that LUMO2 satisfies the following formula. LUMO1-0.50≦LUMO2≦LUMO1-0.20

[0070] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.25

[0071] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.30

[0072] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.35

[0073] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.40

[0074] When LUMO2 is in the above range, the light-emitting device according to one embodiment of the present invention can be a tandem light-emitting device having good characteristics such as low driving voltage, regardless of whether or not it is subjected to a photolithography process involving exposure of the EL layer to the atmosphere, and can also be a tandem light-emitting device with good reliability.

[0075] The metal or metal oxide, the first organic compound, and the second organic compound interact with each other to form a donor level (SOMO level or HOMO level). This reduces the barrier for electron injection into the electron transport layer, and allows electrons generated in the intermediate layer to be smoothly injected and transported to the electron transport layer without using a conventional N-type CGL that was significantly deteriorated by a photolithography process involving exposure to the atmosphere. Furthermore, by having LUMO2 in the above range, it is possible to form an intermediate layer that can interact more stably and is less likely to deteriorate even after a photolithography process involving exposure to the atmosphere. Therefore, even after a photolithography process involving exposure of the EL layer to the atmosphere, it is possible to smoothly inject and transport electrons generated in the intermediate layer to the adjacent electron transport layer, and an increase in driving voltage is suppressed, making it possible to fabricate a highly reliable tandem light-emitting device using a photolithography process.

[0076] The HOMO and LUMO levels of organic compounds are generally estimated by CV (cyclic voltammetry), photoelectron spectroscopy, optical absorption spectroscopy, inverse photoelectron spectroscopy, etc. When comparing values ​​between different compounds, it is preferable to use values ​​estimated by the same measurement.

[0077] In this way, by using an organic compound (first organic compound) having 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 in the intermediate layer, an intermediate layer that is resistant to oxygen and water in the atmosphere, as well as water and chemicals used in the lithography process can be formed. Therefore, one embodiment of the present invention can provide a light-emitting device that has excellent moisture resistance, water resistance, oxygen resistance, and chemical resistance, a low driving voltage, and good luminous efficiency.

[0078] The structure of the region (first region) containing an organic compound (first organic compound) having 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 can be selected from a mixed layer of the metal or metal oxide, the first organic compound, and the second organic compound, and a laminated structure of a layer containing the metal or metal oxide, a layer containing the first organic compound, and a layer containing the second organic compound. When the first region has a laminated structure of a layer containing the metal or metal oxide, a layer containing the first organic compound, and a layer containing the second organic compound, it is preferable that the layer containing the metal or metal oxide is on the cathode side, the layers containing the first organic compound and the second organic compound are on the anode side and are laminated in contact with each other, and the layers containing the first organic compound and the second organic compound are in contact with the light-emitting unit on the anode side.

[0079] When the first region 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 laminated structure, which increases productivity and facilitates mass production.

[0080] When alkali metals or alkaline earth metals, such as lithium oxide (Li2O), and their oxides are used in an N-type CGL having the conventional configuration of a tandem-type light-emitting device, the light-emitting device exhibits good characteristics if it is fabricated through a vacuum integrated process (without exposure to air). However, as mentioned above, when fabricated through a photolithography process involving exposure of the EL layer to air, the driving voltage increases significantly compared to light-emitting devices fabricated through a vacuum integrated process. This is thought to be due to the deterioration of the alkali metals or alkaline earth metals and their oxides due to exposure to air, as mentioned above, resulting in a decrease in donor properties.

[0081] In one embodiment of the present invention, by using an alkali metal or alkaline earth metal such as lithium oxide (LiO) or an oxide thereof, an organic compound (first organic compound) containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring in the intermediate layer, it is possible to obtain a light-emitting device having excellent characteristics similar to those of a light-emitting device fabricated through a vacuum integrated process, even if the light-emitting device is fabricated through a photolithography process involving exposure to air.

[0082] This is because, by using an organic compound (first organic compound) containing an alkali metal or alkaline earth metal and its oxide and a first π-electron-deficient heteroaromatic ring having an electron-donating group in the first region, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, a donor level (SOMO level or HOMO level) is formed by interaction, and since the absolute value of the stabilization energy by the interaction is large and the energy level is high, it is possible to form a configuration that reduces the electron injection barrier from the intermediate layer to the electron transport layer even after exposure to the atmosphere, and smoothly injects and transports electrons generated in the intermediate layer to the electron transport layer. As a result, a tandem light-emitting device with good characteristics can be obtained in which the increase in driving voltage is suppressed even after exposure to the atmosphere.

[0083] In this way, if the tandem light-emitting device of one embodiment of the present invention uses a first region containing an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring instead of a conventional N-type CGL, it is possible to realize a tandem light-emitting device having good characteristics even after a process of exposing the EL layer to the atmosphere. That is, by applying the configuration of one embodiment of the present invention, it is possible to realize a tandem light-emitting device having good characteristics, which is manufactured by a photolithography method including a process of exposing the EL layer to the atmosphere. This makes it possible to provide a display device with very high resolution and good characteristics.

[0084] As described above, by providing a region (first region) containing an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, instead of the conventional N-type CGL, in the intermediate layer of a tandem light-emitting device, it becomes easy to obtain a device with good characteristics even in the case of a tandem light-emitting device manufactured via an air exposure process.

[0085] The intermediate layer of the light-emitting device according to one embodiment of the present invention is a tandem-type light-emitting device having the first region as described above. The intermediate layer preferably includes a second region that is a P-type CGL. A third region may be provided between the first region and the second region. By forming the third region, it is possible to obtain effects such as smoothing the transfer of electrons between the first region and the second region to reduce the driving voltage, and reducing the interaction between the first region and the second region to improve reliability.

[0086] <First Area> The first region is a region provided on the anode side of the intermediate layer as described above, and includes an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring. The first region is in contact with the light-emitting unit on the anode side.

[0087] <Metal or metal oxide> The metal or metal oxide contained in the first region can be an alkali metal (Group 1 element) such as Li, an alkaline earth metal (Group 2 element) such as Mg or Ca, a Group 3 element including a lanthanide such as Y, Eu or Yb, a Group 11 element such as Cu, Ag or Au, a Group 12 element such as Zn, an earth metal (Group 13 element) such as Al or In, or a metal or metal oxide including a Group 14 element such as Sn.

[0088] When an alkali metal or alkaline earth metal and its oxide are used as the metal or metal oxide, the donor level formed by interaction with the first organic compound and the second organic compound can be made to be a high energy level, and electrons generated in the intermediate layer can be smoothly injected and transported to the electron transport layer, so that a light-emitting device that emits light with a low driving voltage and high luminous efficiency can be provided. In addition, transition metals and their oxides are preferred because they are stable and have low reactivity with components such as water and oxygen in the atmosphere. Among the above, it is preferred to use a metal or metal oxide containing an element belonging to an odd group (Group 1, Group 3, Group 11, or Group 13) of the periodic table, because it is easy to interact with the first organic compound and the second organic compound and easy to form a donor level.

[0089] In addition, metals or metal oxides that have a low melting point and can be formed into a film by vacuum deposition are preferred because they can easily form a mixed layer or laminate 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 can be suitably used for vacuum deposition. In addition, metals or metal oxides of Group 11 elements and Group 13 elements are preferred because they are stable to oxygen and water in the atmosphere. As metals or metal oxides that can be formed into a film by vacuum deposition, the melting point at normal pressure is preferably 2000°C or less, preferably 1500°C or less, and more preferably 1000°C or less, or the sublimation temperature under reduced pressure (vacuum of 1 Pa or less) is preferably 1500°C or less, preferably 1000°C or less, and more preferably 500°C or less.

[0090] Specific examples of the metal or metal oxide that can be used include lithium, magnesium, calcium, silver, zinc, indium, and oxides thereof. Note that even if a metal is a single substance, it may be oxidized to a metal oxide during a process such as film formation or exposure to the atmosphere.

[0091] Specific examples of such metal materials are particularly preferred, including lithium, magnesium, calcium, ytterbium, silver, zinc, aluminum, and indium.

[0092] <First organic compound> The first organic compound contained in the first region can be an organic compound having a π-electron-deficient heteroaromatic ring. It is more preferable to use an organic compound having a π-electron-deficient heteroaromatic ring having an electron-donating group as the first organic compound, since the electron density of the π-electron-deficient heteroaromatic ring can be increased.

[0093] As the organic compound having a π-electron-deficient heteroaromatic ring, an organic compound having a nitrogen-containing heteroaromatic ring is preferred, and as the nitrogen-containing heteroaromatic ring, a pyridine ring is preferred, and an organic compound having a heteroaromatic ring containing two or more pyridine rings is particularly preferred. 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 a metal or metal oxide, which makes it easier for interaction with the metal or metal oxide to occur.

[0094] Among organic compounds having heteroaromatic rings containing two or more pyridine rings, organic compounds having a bipyridine skeleton are preferred because the nitrogen atom is more likely to coordinate to a metal or metal oxide, and therefore interactions with the metal or metal oxide occur easily. Furthermore, phenanthroline rings are preferred because they are rigid and stable. In particular, organic compounds having a 1,10-phenanthroline ring are preferred because the two nitrogen atoms contained therein are located at positions that make it easy to coordinate to a metal or metal oxide, and therefore interactions with the metal or metal oxide occur easily.

[0095] 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 an electron-donating group into 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, making it easier for the nitrogen atoms to interact with a metal or metal oxide.

[0096] Examples of the electron donating group of the π-electron deficient heteroaromatic ring include an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group. However, the electron donating group that is preferably introduced into the π-electron deficient heteroaromatic ring is not limited to these. Any group that can increase the electron density of the π-electron deficient heteroaromatic ring by introducing it into the π-electron deficient heteroaromatic ring can be used as the electron donating group. In addition, the electron donating group may be introduced into the π-electron deficient heteroaromatic ring via an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0097] Specific examples of alkyl groups that can be used as the electron-donating group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a sec-hexyl group, a tert-hexyl group, a neohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group.

[0098] Specific examples of alkoxy groups that can be used as the electron-donating group include a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, an isobutoxy group, a tert-butoxy group, an n-pentyloxy group, an isopentyloxy group, a sec-pentyloxy group, a tert-pentyloxy group, a neopentyloxy group, an n-hexyloxy group, an isohexyloxy group, a sec-hexyloxy group, a tert-hexyloxy group, and a neohexyloxy group.

[0099] Specific examples of the aryloxy group that can be used as the electron-donating group include a phenoxy group, an o-tolyloxy group, an m-tolyloxy group, a p-tolyloxy group, a mesityloxy group, an o-biphenyloxy group, an m-biphenyloxy group, a p-biphenyloxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 2-fluorenyloxy group, etc. The aryloxy group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, etc.

[0100] Specific examples of the alkylamino group that can be used as the electron donating group include a dimethylamino group and a diethylamino group.

[0101] Specific examples of the arylamino group that can be used as the electron-donating group include a diphenylamino group, a bis(α-naphthyl)amino group, a bis(m-tolyl)amino group, etc. The arylamino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, a phenyl group, etc.

[0102] Specific examples of heterocyclic amino groups that can be used as the electron donating group include groups represented by the following structural formulas (R-1) to (R-26). The heterocyclic amino group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0103] [ka]

[0104] 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 preferable as the electron donating group. Among them, the group represented by the structural formula (R-3), (R-4), (R-8) or (R-21) is preferable because it has high electron donating property and can further increase the electron density of the phenanthroline ring.

[0105] Specific examples of the electron-donating group include groups represented by the following structural formulas (R-27) and (R-28).

[0106] [ka]

[0107] The organic compound having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound may have both the above-mentioned electron-donating group and other substituents. In addition to the above-mentioned electron-donating group, a specific example of a substituent that can be introduced into the π-electron-deficient heteroaromatic ring is an aryl group. Specific examples of the aryl group include a phenyl group, an o-tolyl group, a m-tolyl group, a p-tolyl group, a mesityl group, an o-biphenyl group, a m-biphenyl group, a p-biphenyl group, a 1-naphthyl group, a 2-naphthyl group, and a 2-fluorenyl group. The aryl group may further have a substituent, and specific examples of the substituent include an alkyl group, an alkoxy group, and a phenyl group.

[0108] Specific examples of organic compounds having a π-electron-deficient heteroaromatic ring that can be used as the first organic compound are shown in structural formulas (100) to (110). Note that the organic compounds that can be used as the first organic compound are not limited to these.

[0109] [ka]

[0110] It is preferable that the first organic compound has a small minimum negative value (large absolute negative value) of electrostatic potential (ESP) since this increases the absolute value of stabilization energy due to interaction with the metal or metal oxide.

[0111] In an organic compound having a π-electron-deficient heteroaromatic ring, the electrostatic potential around the heteroatom of the π-electron-deficient heteroaromatic ring tends to be negative. However, by introducing an electron-donating group into the π-electron-deficient heteroaromatic ring, the electrostatic potential around the heteroatom of the π-electron-deficient heteroaromatic ring can be further reduced (the absolute value of the negative potential can be increased).

[0112] The electrostatic potential is the interaction energy between a positive point charge with a unit charge and the electron distribution of a molecule. The value of the electrostatic potential also changes depending on the threshold of the electron density.

[0113] In order to increase the efficiency of the interaction with a metal or metal oxide, it is preferable that the minimum value of the electrostatic potential of the first organic compound is smaller (more negatively) than the minimum value of the electrostatic potential of the unsubstituted π-electron-deficient heteroaromatic ring.

[0114] Specifically, the threshold for the electron density distribution in atomic units is set to 0.0004e / a0 3 (e is the elementary charge (1e=1.60218×10 -19 C), a0 is the Bohr radius (1a0=5.29177×10 -11 m)), the minimum value of the electrostatic potential of the first organic compound is -0.085E h (E h is the Hartree energy (1E h =27.211eV) or less is preferable, -0.090E h More preferably, the threshold value of the electron density distribution in atomic units is 0.003e / a0 3 The minimum electrostatic potential of the first organic compound is -0.12Eh Less than or equal to -0.13E is preferred h The ESP of the first organic compound is more preferably 0.0004e / a0 or less. 3 The minimum value is -0.085E h The threshold for the electron density distribution in atomic units is 0.003e / a0 3 The minimum value is -0.12E h It is even more preferable that:

[0115] The minimum electrostatic potential (ESP) values ​​of the organic compounds represented by the above structural formulas (100) to (107), and BPhen, mPPhen2P, NBPhen, Phen, and Hid2Phen, which are shown as organic compounds that can be used for 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), BPhen, mPPhen2P, NBPhen, Phen, and Hid2Phen are shown below.

[0116] [ka]

[0117] Gaussian09 was used as the quantum chemical calculation program. Calculations were performed using an SGI8600 manufactured by HPE. The most stable structure in the ground state of each organic compound was calculated using density functional theory (DFT). 6-311G(d,p) was used as the basis function, and B3LYP was used as the functional.

[0118] Table 1 shows the analysis results of the electrostatic potential in the ground state of each organic compound. The electrostatic potential is the interaction energy between a positive point charge with a unit charge and the electron distribution of the molecule. The value of the electrostatic potential also changes depending on the threshold of the electron density. In Table 1, the density threshold in atomic units is set to 0.0004e / a0 3 or 0.003e / a0 3 The electrostatic potential in the electron density distribution in atomic units is shown when

[0119] [Table 1]

[0120] From the above table, the organic compounds represented by the structural formulas (100) to (103) and Hid2Phen have an electron density distribution threshold of 0.0004e / a0 3 When this is done, the minimum value of ESP is -0.085E h The organic compounds represented by the structural formulas (100) to (103) and Hid2Phen have an electron density distribution threshold of 0.003e / a0 or less in atomic units. 3 The minimum value of ESP is -0.12E h and it has been found that these are more preferable as the first organic compound.

[0121] This is because the organic compounds represented by structural formulas (100) to (103) and Hid2Phen have electron-donating groups at the 4- and 7-positions of the 1,10-phenanthroline ring, and therefore have high electron-donating properties to the nitrogens at the 1- and 10-positions of the phenanthroline ring.

[0122] The organic compounds represented by the structural formulas (101) and (103) and Hid2Phen have an electron density distribution threshold of 0.0004e / a03 When this is done, the minimum value of ESP is -0.090E h The organic compound represented by the structural formula (103) and Hid2Phen have an electron density distribution threshold of 0.003e / a0 or less in atomic units. 3 When this is done, the minimum ESP value is -0.13E h It has been found that the following is particularly preferable as the first organic compound.

[0123] In addition, the organic compound represented by the structural formula (103) and Hid2Phen have an electron density distribution threshold of 0.0004e / a0 3 When this is done, the minimum value of ESP is -0.090E h The threshold for the electron density distribution in atomic units is 0.003e / a0 3 When this is done, the minimum ESP value is -0.13E h and furthermore, it has been found that these are preferable as the first organic compound.

[0124] In addition, when the first organic compound has a high basicity, it is possible to significantly reduce the hole transport property in the first region of the intermediate layer by interacting with holes, and thus it is possible to obtain a light-emitting device with high efficiency and low driving voltage, which is preferable. Specifically, the acid dissociation constant pKa of the first organic compound is preferably 8 or more, more preferably 10 or more, and even more preferably 12 or more.

[0125] If the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa of each skeleton of the organic compound is examined, and the largest acid dissociation constant pKa selected from these can be regarded as the acid dissociation constant pKa of the organic compound.

[0126] Alternatively, the acid dissociation constant may be calculated. For example, the acid dissociation constant pKa can be calculated using the following calculation method.

[0127] The initial molecular structure of each molecule serving as a calculation model is set to the most stable structure (singlet ground state) obtained from first-principles calculations.

[0128] For the above first-principles calculations, Jaguar, a quantum chemistry calculation software made by Schrodinger, is used, and the most stable structure in the singlet ground state is calculated using density functional theory (DFT). 6-31G** is used as the basis function, and B3LYP-D3 is used as the functional. The structure for which the quantum chemistry calculations are performed is sampled by performing conformational analysis using mixed torsional / low-mode sampling using Schrodinger's Maestro GUI.

[0129] In the pKa calculation, one or more atoms of each molecule are designated as basic sites, and a Macro Model is used to search for the stable structure of the protonated molecule in water, and a conformational search is performed using the OPLS2005 force field, and the lowest energy conformer is used. Using the Jaguar pKa calculation module, the structure is optimized with B3LYP / 6-31G*, and then a single-point calculation is performed with cc-pVTZ(+), and the pKa value is calculated using empirical corrections for functional groups. For molecules with one or more atoms designated as basic sites, the largest value among the results obtained is used as the pKa value. The obtained pKa value is shown.

[0130] The acid dissociation constant pKa of 2,9hpp2Phen is 13.35, the acid dissociation constant pKa of 4,7hpp2Phen is 13.42, the acid dissociation constant pKa of Pyrrd-Phen is 11.23, the acid dissociation constant pKa of mPPhen2P is 5.16, the acid dissociation constant pKa of NBPhen is 5.59, and the acid dissociation constant pKa of BPhen is 5.62.

[0131] <Estimation of interactions between metals and organic compounds using quantum chemical calculations> Here, the spin density and electrostatic potential (ESP) when a metal, a first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring, and a second organic compound having a π-electron-deficient heteroaromatic ring interact with each other were analyzed by quantum chemical calculations. The calculations were 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.

[0132] Gaussian09 was used as a quantum chemical calculation program. The calculations were performed using an SGI8600 manufactured by HPE. The most stable structures in the ground states of the first organic compound and the second organic compound, the composite material of the first organic compound and a metal, the composite material of the second organic compound and a metal, and the composite material of the first organic compound, the second organic compound and a metal were calculated using density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as the functional. The total energy in DFT is expressed as the sum of the exchange-correlation energy, which includes the potential energy, the electrostatic energy between electrons, the kinetic energy of electrons, and all the complex interactions between electrons. In DFT, the exchange-correlation interaction is approximated by a functional (meaning a function of a function) of a one-electron potential expressed in terms of electron density, so the calculations are highly accurate.

[0133] 19(A) to 19(C) show the analysis results of the spin density distribution in the ground state of a composite material of the first organic compound (PyrrdPhen) and a metal (Ag), a composite material of the second organic compound (11mDBtBPPnfpr) and a metal (Ag), and a composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and a metal (Ag). The spheres in the figures represent the atoms that make up the compounds, and the clouds around the atoms have a density value of 0.003e / a0 in atomic units. 3 The figure shows the spin density distribution when the first organic compound (Pyrrd-Phen) and the second organic compound (11mDBtBPPnfpr) are in a singlet ground state, and the localized state of the doublet ground state in the compound is shown. Since the ground state of the first organic compound (Pyrrd-Phen) and the ground state of the second organic compound (11mDBtBPPnfpr) are in a singlet ground state, no spin density distribution is observed.

[0134] In the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) to form a composite material. By doing so, as shown in Figure 19 (A), it can be seen that some of the spins derived from the unpaired electrons of the metal (Ag) are distributed to a part of the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), especially the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs. However, because the interaction is weak, most of the spins are distributed to the metal (Ag).

[0135] In addition, in the doublet ground state of the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to form a composite material. By doing so, as shown in Figure 19 (B), it can be seen that a part of the spin derived from the unpaired electron of the metal (Ag) is distributed to a part of the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), especially the nitrogen atom (N) having an unshared electron pair. However, because the interaction is weak, most of the spin is distributed to the metal (Ag).

[0136] On the other hand, in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) according to one embodiment of the present invention, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) interact with each other, and the metal (Ag) is coordinated to the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), thereby stabilizing the composite material. By doing so, as shown in Figure 19(C), it can be seen that the spin originating from the unpaired electron of the metal (Ag) is localized in the second organic compound (11mDBtBPPnfpr). In addition, no spin density distribution is observed in the metal (Ag). From this, it can be seen that the second organic compound (11mDBtBPPnfpr) is in a radical anion state due to the interaction between the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag).

[0137] Next, the analysis results of electrostatic potential maps in the ground state of the first organic compound (PyrrdPhen), the second organic compound (11mDBtBPPnfpr), a composite material of the first organic compound (PyrrdPhen) and a metal (Ag), a composite material of the second organic compound (11mDBtBPPnfpr) and a metal (Ag), and a composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr) and a metal (Ag) are shown in Figures 20(A), 20(B), and 21(A) to 21(C). The spheres in the figures represent the atoms that make up the compounds, and the clouds around the atoms have a density value of 0.0004e / a0 in atomic units. 3 The electrostatic potential in the electron density distribution when is expressed as follows. The electrostatic potential is the interaction energy between a positive point charge with unit electric charge and the electron distribution of the molecule, and the electrostatic potential map represents the electrostatic potential in the isoelectron density surface with colors, with regions with negative electrostatic potential represented in red and regions with positive electrostatic potential represented in blue, indicating that atoms in regions with negative electrostatic potential have negative charges and atoms in regions with positive electrostatic potential have positive charges. However, since Figures 20 and 21 are grayscale images, in order to indicate regions with negative electrostatic potential and regions with positive electrostatic potential, the dark red parts (i.e., regions with negative electrostatic potential) are surrounded by thick dotted lines and the dark blue parts (i.e., regions with positive electrostatic potential) are surrounded by thin dashed lines.

[0138] As shown in FIG. 20(A), in the singlet ground state of the first organic compound (Pyrrd-Phen), it can be seen that the electrostatic potential around the nitrogen atoms (nitrogen atoms (N) at positions 1 and 10) having unshared electron pairs in the 1,10-phenanthroline ring is negative. In addition, the Mulliken partial charge of the N atom is negative, at -0.29e in atomic units. From these facts, it can be seen that the N atom has a negative partial charge.

[0139] In addition, as shown in FIG. 20(B), in the singlet ground state of the second organic compound (11mDBtBPPnfpr), it can be seen that the electrostatic potential around the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring is negative. In addition, the Mulliken partial charge of the N atom was negative at -0.31e in atomic units. From these, it can be seen that the N atom has a negative partial charge.

[0140] In addition, in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen) and the metal (Ag), the first organic compound (Pyrrd-Phen) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen), forming a composite material. As a result, as shown in FIG. 21(A), it can be seen that the electrostatic potential around the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the metal (Ag) is negative. In addition, the Mulliken partial charge of the N atom is -0.37e in atomic units, and the Mulliken partial charge of the metal (Ag) is -0.18e in atomic units, which are negative. From these facts, it is found that the N atom and the Ag atom have a negative partial charge.

[0141] In addition, in the doublet ground state of the composite material of the second organic compound (11mDBtBPPnfpr) and the metal (Ag), the second organic compound (11mDBtBPPnfpr) and the metal (Ag) interact with each other, and the metal (Ag) is stabilized by coordinating with the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) to form a composite material. As a result, as shown in Figure 21 (B), it can be seen that the electrostatic potential around the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) and the metal (Ag) is negative. In addition, the Mulliken partial charge of the N atom is -0.38e in atomic units, and the Mulliken partial charge of the metal (Ag) is -0.09e in atomic units, which is negative. From these, it can be seen that the N atom and the Ag atom have negative partial charges.

[0142] On the other hand, in the doublet ground state of the composite material of the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) according to one embodiment of the present invention, the first organic compound (Pyrrd-Phen), the second organic compound (11mDBtBPPnfpr), and the metal (Ag) interact with each other, and the metal (Ag) is coordinated to the nitrogen atom (nitrogen atom (N) at positions 1 and 10) having an unshared electron pair in the 1,10-phenanthroline ring of the first organic compound (Pyrrd-Phen) and the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr), thereby stabilizing the composite material. As a result, as shown in FIG. 21(C), it can be seen that the positive electrostatic potential is mainly distributed in the metal (Ag) and the first organic compound (Pyrrd-Phen), and the negative electrostatic potential is mainly distributed in the second organic compound (11mDBtBPPnfpr). It can also be seen that the electrostatic potential around the nitrogen atom (N) having an unshared electron pair in the phenanthro[9',10':4,5]furo[2,3-b]pyrazine ring of the second organic compound (11mDBtBPPnfpr) is negative, while the electrostatic potential around the metal (Ag) is positive. In addition, the Mulliken partial charge of the N atom is negative at -0.62e in atomic units, while the Mulliken partial charge of the metal (Ag) is positive at 0.37e in atomic units. From these, it can be seen that the charge of the Ag atom is distributed to the N atom.

[0143] From the above, it is understood that this combination forms a donor level by interaction between a first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring and a metal, and further functions as an electron donor for a second organic compound having a π-electron-deficient heteroaromatic ring. In one embodiment of the present invention, by using this combination of materials for an intermediate layer, an intermediate layer having good electron injection properties and resistance to oxygen and water in the air, as well as water and chemicals used in the process of a lithography method can be formed, and thus a light-emitting device with reduced driving voltage and high luminous efficiency can be obtained.

[0144] <Estimation of SOMO or HOMO levels in the interaction between metals and organic compounds by quantum chemical calculations> Next, we used quantum chemical calculations to estimate the stabilization energy when a metal, a first organic compound having an electron-donating group and a π-electron-deficient heteroaromatic ring, and a second organic compound having a π-electron-deficient heteroaromatic ring interact, as well as the SOMO level or HOMO level formed at that time.

[0145] Gaussian09 was used as a quantum chemical calculation program. The calculation was performed using an SGI8600 manufactured by HPE. First, the most stable structures in the ground states of the first organic compound, the second organic compound, and the metal, and 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 were calculated using density functional theory (DFT). 6-311G(d,p) and LanL2DZ were used as basis functions, and B3LYP was used as functional. Next, the stabilization energy was calculated from the difference between the total energy of the composite material of the organic compound and the metal and the sum of the total energy of the organic compound alone and the total energy of the metal alone. In other words, (stabilization energy) = (total energy of the composite material of the organic compound and the metal) - (total energy of the organic compound alone) - (total energy of the metal alone).

[0146] The first organic compound was 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen), and the second organic compounds were 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzo The results of calculations of furo[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), and 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn) using indium (In) as the metal are shown in the table below. Note that the energy levels of the HOMO and SOMO in the table are calculated values ​​and may differ from the actual measurements.

[0147] [Table 2]

[0148] [Table 3]

[0149] [Table 4]

[0150] From the above table, the stabilization energy of the composite material consisting of two materials, a metal (In) and a second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), was a negative value. This indicates that when the organic compound is mixed with a metal, the organic compound interacting with the metal is more energetically stable than the organic compound not interacting with the metal. In addition, the SOMO levels formed at this time are all higher than the HOMO levels of the first organic compound (Pyrrd-Phen) and the second organic compound (NBPhen, 9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn).

[0151] In addition, a composite material of a second organic compound (NBPhen) having the same 1,10-phenanthroline ring as the π-electron-deficient heteroaromatic ring as the first organic compound Pyrrd-Phen, and a metal (In), has a larger absolute value of stabilization energy and is more stable than composite materials 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), and also forms a higher SOMO level.

[0152] Here, it can be seen that a composite material made of three materials, namely, a metal (In) according to one embodiment of the present invention, a first organic compound (Pyrrd-Phen), and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn), has a larger absolute value of stabilization energy and is more stable than a composite material made of two materials, namely, a metal (In) and a second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn). In addition, the SOMO level formed at this time is higher than the HOMO levels of the first organic compound (Pyrrd-Phen) and the second organic compound (9mDBtBPNfpr, 8mpTP-4mDBtPBfpm, mPn-mDMePyPTzn, βNP-SFx(4)Tzn). A high SOMO level is preferable because it has excellent electron injection properties.

[0153] In this case, the composite 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 of the first organic compound Pyrrd-Phen, the first organic compound (Pyrrd-Phen), and a metal (In) has a larger absolute value of stabilization energy and is more stable than the composite 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 a metal (In), and the SOMO level formed is also higher.

[0154] In this manner, when an organic compound having 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, it is preferable that the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different rings, because this provides superior stability and electron injection properties.

[0155] As shown in the above table, the stabilization energy of the composite material of the metal, the first organic compound, and the second organic compound is preferably large in absolute value and more stable. The SOMO level formed in this case is higher than the HOMO levels of the first organic compound and the second organic compound. A high SOMO level is preferable because it has excellent electron injection properties. In addition, a high SOMO level can be formed even if a metal stable in the air, such as silver or indium, is used without using an alkali metal compound, so that an intermediate layer with excellent stability and electron injection properties can be formed.

[0156] <Second organic compound> The first region of the intermediate layer contains a second organic compound containing a π-electron-deficient heteroaromatic ring in addition to a metal or metal oxide and a first organic compound. By containing the second organic compound, it is possible to improve heat resistance, electron transport properties, and the like. In one embodiment of the present invention, when the π-electron-deficient heteroaromatic ring of the first organic compound is a first π-electron-deficient heteroaromatic ring and the π-electron-deficient heteroaromatic ring of the second organic compound is a second π-electron-deficient heteroaromatic ring, it is preferable that the first π-electron-deficient heteroaromatic ring and the second π-electron-deficient heteroaromatic ring are different rings.

[0157] Furthermore, as the second π-electron-deficient heteroaromatic ring, a heteroaromatic ring having an azole skeleton (imidazole ring, pyrazole ring, oxazole ring, thiazole ring, triazole ring, oxadiazole ring, thiadiazole ring), a heteroaromatic ring having a pyridine skeleton, a heteroaromatic ring having a diazine skeleton, or a heteroaromatic ring having a triazine skeleton is preferred, with a diazine ring (pyrazine ring, pyrimidine ring, pyridazine ring) or a triazine ring being particularly preferred due to their electrochemical stability and high electron transport property.

[0158] The second π-electron-deficient heteroaromatic ring may have a condensed ring structure.

[0159] In one embodiment of the present invention, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound and is preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.20 eV lower than the LUMO level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.25 eV lower than the LUMO level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.30 eV lower than the LUMO level of the first organic compound, more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.35 eV lower than the LUMO level of the first organic compound, and still more preferably at least 0.50 eV lower than the LUMO level of the first organic compound and at most 0.40 eV lower than the LUMO level of the first organic compound.

[0160] That is, assuming that the LUMO level of the first organic compound is "LUMO1 (eV)" and the LUMO level of the second organic compound is "LUMO2 (eV)", it is preferable that LUMO2 satisfies the following formula. LUMO1-0.50≦LUMO2≦LUMO1-0.20

[0161] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.25

[0162] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.30

[0163] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.35

[0164] More preferably, LUMO2 satisfies the following formula: LUMO1-0.50≦LUMO2≦LUMO1-0.40

[0165] When LUMO2 is in the above range, the light-emitting device according to one embodiment of the present invention can be a tandem light-emitting device having good characteristics such as low driving voltage, regardless of whether or not it is subjected to a photolithography process involving exposure of the EL layer to the atmosphere, and can also be a tandem light-emitting device with good reliability.

[0166] The second organic compound may be an organic compound having an electron transporting property. The organic compound having an electron transporting property may be an organic compound having an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600. -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferable. Note that other substances can also be used as long as they have a higher electron transporting property than a hole transporting property.

[0167] 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]benzene (abbreviation: OXD-7), and ]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 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: DBimBphen), and other organic compounds with an azole skeleton, such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2- [3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-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-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6 -Bis[3-(phenanthren-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-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 8-[3'-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl-3-yl)naphtho[1',2':4, 5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol Organic compounds with a diazine skeleton, such as 2-(biphenyl-2-yl)quinazolin-2-yl)-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), and 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl -9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPyTz ), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylene- 2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3, Examples of organic compounds having a triazine skeleton include 5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn), and 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz).

[0168] Among the above, ZADN, mSiTrz, mPn-mDMePyPTzn, 8mpTP-4mDBtPBfpm, 11mDBtBPPnfpr, and βNP-SFx(4)Tzn are preferable as the second organic compound because they have appropriate LUMO levels. By using these organic compounds, it becomes easy to obtain a tandem light-emitting device with good characteristics in which an increase in driving voltage is suppressed even in a light-emitting device that has undergone a process involving exposure of the EL layer to the atmosphere.

[0169] The carbon number of the second organic compound is preferably from 25 to 100. By setting the carbon number in this range, an organic compound with excellent sublimability can be obtained, so that thermal decomposition of the organic compound can be suppressed during vacuum deposition, and good material usage efficiency can be obtained.

[0170] In addition, it is preferable to use an organic compound having a glass transition temperature Tg of 100° C. or higher as the second organic compound. This allows the intermediate layer to be a layer that has good heat resistance and is difficult to crystallize. Therefore, the organic compound layer can be a layer that is difficult to crystallize even when a part of the organic compound layer is processed by a lithography method.

[0171] In addition, the second organic compound can be an organic compound having an acid dissociation constant pKa of less than 4. This can reduce the solubility of the second organic compound in water, thereby increasing the resistance to water and chemicals used in the lithography process.

[0172] Compared with the solubility in water of an organic compound having an acid dissociation constant pKa of 4 or more, the solubility in water of an organic compound having an acid dissociation constant pKa smaller than 4 is low. In addition, compared with the case where an organic compound having an acid dissociation constant pKa of 4 or more is used as the second organic compound, the water resistance of the intermediate layer can be improved by using an organic compound having an acid dissociation constant pKa smaller than 4 as the second organic compound. In addition, the occurrence of defects such as peeling of the intermediate layer from other layers during the manufacturing process can be suppressed. This makes it possible to suppress the occurrence of defects that cause defects in the light-emitting device.

[0173] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, BP-BPIcz(II)Tzn, etc. can be used as the second organic compound.

[0174] The acid dissociation constant pKa of 4,8mDBtP2Bfpm is 0.60. The acid dissociation constant pKa of 11mDBtBPPnfpr is -1.85. If the acid dissociation constant pKa of an organic compound is unknown, the acid dissociation constant pKa of each skeleton of the organic compound can be examined, and the largest acid dissociation constant pKa selected from these can be regarded as the acid dissociation constant pKa of the organic compound.

[0175] For example, the solubility parameter δ is 4.0 MPa. 0.5 An organic compound having the following polarization term δp can be used as the second organic compound. For example, a solubility parameter δ of 4.0 MPa 0.5 4.0MPa, compared with the solubility in water of organic compounds with a larger polarization term δp. 0.5 Organic compounds with a polarization term δp below 4.0MPa have low solubility in water. 0.5 4.0MPa compared to when an organic compound having a larger polarization term δp is used as the second organic compound. 0.5 By using an organic compound having the following polarization term δp for the second organic compound, the water resistance of the intermediate layer can be improved. In addition, the occurrence of defects such as the intermediate layer peeling off from other layers during the photolithography process can be suppressed. This makes it possible to suppress the occurrence of defects that cause defects in the light-emitting device.

[0176] The polarization term δp of the solubility parameter δ of water is 16.0MPa. 0.5 This is described in JP 2017-173056 A.

[0177] The greater the difference between the polarization term δp of the solubility parameter δ and the polarization term δp of the solvent water, the lower the solubility in water and the more preferable it is. 0.5 It is preferable to use an organic compound having the following polarization term δp as the second organic compound.

[0178] For example, 8BP-4mDBtPBfpm, 4,8mDBtP2Bfpm, 6BP-4Cz2PPm, 2mDBTBPDBq-II, 9mDBtBPNfpr, 11mDBtBPPnfpr, mPCCzPTzn-02, and BP-BPIcz(II)Tzn can be used as the second organic compound.

[0179] The polarization term δp of the solubility parameter δ of 8BP-4mDBtPBfpm is 3.5MPa. 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 It is.

[0180] The polarization term δp of the solubility parameter δ was calculated using the following calculation method.

[0181] The classical molecular dynamics calculation software used was Desmond manufactured by Schrodinger. The force field used was OPLS2005. The calculations were performed using Apollo6500 manufactured by HPE.

[0182] A reference cell with about 32 molecules was used for the calculation model. The initial molecular structure of each compound was a mixture of the most stable structure (singlet ground state) obtained from first-principles calculations and multiple structures with energy close to the most stable structure in equal ratios, and the molecules were randomly arranged to prevent collisions. After that, the structures were randomly moved and rotated by Monte Carlo simulated annealing using OPLS2005 as the force field to move the molecules. Furthermore, the molecules were moved toward the center of the reference cell to maximize the density, and the initial arrangement was created.

[0183] For the above first-principles calculations, quantum chemistry calculation software Jaguar was used, and the most stable structure in the singlet ground state was calculated using density functional theory (DFT). 6-31G** was used as the basis function, and B3LYP-D3 was used as the functional. The structure for which the quantum chemistry calculations were performed was sampled by performing conformational analysis using mixed torsional / low-mode sampling using Schrodinger's Maestro GUI. The calculations were performed using HPE's Apollo 6500.

[0184] The above initial configuration was subjected to Brownian motion simulation, followed by NVT ensemble, and then calculation was performed with sufficient relaxation time (30 ns) for the step time (2 fs) to reproduce molecular vibrations under the condition of 1 atm and 300 K to calculate the amorphous solid. The solubility parameter δ of the obtained amorphous solid is defined by the following equation.

[0185]

number

[0186] Here, ΔHv represents the heat of vaporization, which is the energy of the reference cell minus the total energy of each molecule averaged over the entire molecular dynamics calculation, Vm represents the molar volume, R represents the gas constant, and T represents the temperature. Note that the solubility parameter shows a tendency for the solubility to decrease as the difference between the solvent substance and the solute substance increases.

[0187] The solubility parameter δ can be decomposed into a dispersion term δd and a polarization term δp. The dispersion term δd is a term contributed by van der Waals interactions, and the polarization term δp is a term contributed by electrostatic interactions. In particular, the solubility of a solute in water is greatly contributed by the electrostatic interactions that occur between the dipoles of the solute and water molecules. In fact, the solubility in water of organic compounds that can be used for the second organic compound shows a good correlation with the polarization term δp of the solubility parameter δ obtained by calculation.

[0188] It is more preferable that the LUMO level of the second organic compound is lower than that of the first organic compound. This makes it easier for the donor level formed by the first organic compound and the metal or metal oxide to donate electrons to the second organic compound. It is also preferable that the second organic compound has electron transport properties, and for this reason, it is also preferable that the LUMO level of the second organic compound is lower than that of the first organic compound.

[0189] The second organic compound has a LUMO level of preferably -3.0 eV to -2.0 eV, more preferably -3.0 eV to -2.5 eV, and the first organic compound has a LUMO level of preferably -3.0 eV to -2.0 eV, more preferably -2.7 eV to -2.0 eV.

[0190] This makes it easier for the first organic compound to donate electrons to the second organic compound from the donor level formed by the first organic compound and the metal or metal oxide, and also makes it easier for the second organic compound to transport electrons.

[0191] In addition, in the first region, in addition to the metal or metal oxide and the first organic compound, a second organic compound is contained, so that the interaction between the materials occurs efficiently. This can be confirmed by measuring the spin density by electron spin resonance (ESR).

[0192] For example, the spin density measured by ESR of a film containing a metal or metal oxide and a first organic compound is preferably higher than the spin density measured by ESR of a film containing a metal or metal oxide and a second organic compound.Also, the spin density measured by ESR of a film containing a metal or metal oxide, a first organic compound, and a second organic compound is preferably higher than the spin density measured by ESR of a film having only two materials, either a metal or metal oxide, a first organic compound, or a second organic compound, and in this case, it can be confirmed that the interaction between the materials occurs efficiently.

[0193] More specifically, the film containing a metal or metal oxide and a first organic compound has a spin density of 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3 or more is preferable. In such a case, it can be confirmed that an interaction between materials occurs efficiently in a layer having a combination of a metal or metal oxide and a first organic compound. Alternatively, a film containing a metal or metal oxide, a first organic compound, and a second organic compound has a spin density resulting from a signal observed in the vicinity of a g value of 2.00 by an electron spin resonance method of, for example, 5×10 16 spins / cm 3 More preferably, 1×10 17 spins / cm 3or more is preferable. In such a case, it can be confirmed that in a layer having a combination of a metal or metal oxide, a first organic compound, and a second organic compound, the interaction between the materials occurs more efficiently than in a layer having only two of these materials. In this case, for a mixed film containing a metal or metal oxide and a second organic compound, the spin density resulting from a signal observed in the vicinity of a g value of 2.00 by electron spin resonance is, for example, 2×10 16 spins / cm 3 For a mixed film containing the first organic compound and the second organic compound, the spin density due to a signal observed in the vicinity of a g value of 2.00 by an electron spin resonance method is 2×10 16 spins / cm 3 The following is the result.

[0194] In the first region, 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 to 10, more preferably 0.2 to 5, and even more preferably 0.5 to 2. Alternatively, the volume ratio is preferably 0.01 to 0.3, more preferably 0.02 to 0.2, and even more preferably 0.05 to 0.1. By having the first region containing the metal or metal oxide and the first organic compound (or the first organic compound and the second organic compound) at such a ratio, an intermediate layer having good electron injection properties can be provided. In addition, the second organic compound does not have to be used, but when the second organic compound is used, the ratio of the first organic compound to the second organic compound is preferably 0.1 to 10, more preferably 0.2 to 5, and even more preferably 0.5 to 2. By mixing the first organic compound and the second organic compound in such a ratio, an intermediate layer having good electron transport properties can be provided. In addition, by using an organic compound having high Tg and good thermal properties as the second organic compound, a light-emitting device with good reliability can be provided.

[0195] The thickness of the first region is preferably 2 nm to 20 nm, more preferably 5 nm to 10 nm. When the first region has a laminated structure of a metal or metal oxide layer and a layer containing a first organic compound, the thickness of the metal or metal oxide layer is preferably 0.1 nm to 5 nm, more preferably 0.2 nm to 2 nm. When the first region has a laminated structure of a metal or metal oxide layer and a layer containing a first organic compound, the thickness of the layer containing the first organic compound is preferably 2 nm to 20 nm, more preferably 5 nm to 10 nm.

[0196] <<Second Area>> The second region is a P-type CGL, and is preferably formed from a composite material containing an organic compound having a hole-transporting property (a third organic compound) and a substance having an electron acceptor property with respect to the organic compound having a hole-transporting property.

[0197] As a substance that has electron acceptor properties with respect to an organic compound that has hole-transport properties, an organic compound having an electron-withdrawing group (such as a halogen group or a cyano group) can be used, and it is more preferable to use an organic compound having at least one of a halogen group and a cyano group. Specifically, for example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, etc. In particular, a compound in which an electron-withdrawing group is bonded to a condensed aromatic ring having a plurality of heteroatoms, such as HAT-CN, is thermally stable and preferable. In addition, radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group, a cyano group, etc.)[3] are preferred because they have extremely high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile].

[0198] In addition to the organic compounds described above, transition metals such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide or oxides thereof can be used as the substance having electron acceptor properties. In this case, one embodiment of the present invention can be said to be a light-emitting device having different metals or metal oxides in the P-type CGL and N-type CGL in the intermediate layer. Alternatively, it can be said to be a light-emitting device having different metals or metal oxides and organic compounds in the P-type CGL and N-type CGL. Since metals or metal oxides are stable, by using metals or metal oxides in both the P-type CGL and the N-type CGL, a tandem light-emitting device having an intermediate layer that is stable against oxygen and water in the air, or against water and chemicals during the manufacturing process can be manufactured.

[0199] As the organic compound having a hole transporting property used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that the organic compound having a hole transporting property used in the composite material is preferably 1×10 -6 cm 2 It is preferable that the organic compound has a hole mobility of 100 / Vs or more. The organic compound having hole transport properties used in the composite material is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferable. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton is preferable, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed to the above rings is preferable.

[0200] Such organic compounds having hole transport properties preferably have any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the organic compounds may be aromatic amines having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the organic compounds having hole transport properties are substances having an N,N-bis(4-biphenyl)amino group, because this allows the manufacture of a light-emitting device with a long life.

[0201] Specific examples of organic compounds having hole transport properties as described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-4-amino-p-terphenyl ]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβ NB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl] 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N- Bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4' -[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'- Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis( 9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, etc. can be mentioned.

[0202] In addition, as a material having hole transport properties, other aromatic amine compounds such as 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), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) can also be used.

[0203] In addition, the material having electron acceptor properties in the P-type CGL preferably has electron acceptor properties. In addition, the material having electron acceptor properties preferably has electron acceptor properties for organic compounds having hole transport properties. When the material having electron acceptor properties has electron acceptor properties, charge separation occurs in the P-type CGL, and the material can function as a charge generation layer, so that the material can function as a tandem intermediate layer. In addition, it is preferable that the P-type CGL exhibits a signal observed by electron spin resonance. For example, when the spin density resulting from a signal observed near a g value of 2.00 is 1×10 17 spins / cm 3 More preferably, 1×10 18 spins / cm 3 More preferably, 1×10 19 spins / cm 3 The above is even more preferable.

[0204] <The Third Region> In addition, a third region may be provided between the first region and the second region of the intermediate layer.

[0205] The third region contains a substance having electron transport properties and has functions such as smoothing the exchange of electrons between the first region and the second region to reduce the driving voltage and reducing the interaction between the first region and the second region to improve reliability.

[0206] The LUMO level of the substance having electron transport properties contained in the third region is preferably between the LUMO level of the acceptor substance in the second region and the LUMO level of the organic compound contained in the layer in contact with the intermediate layer in the light-emitting unit on the anode side.

[0207] In addition, the specific energy level of the LUMO level of the substance having electron transport properties used in the third region is preferably -5.0 eV or more, more preferably -5.0 eV or more and -3.0 eV or less, more preferably -4.30 eV or more and -3.00 eV or less, and more preferably -4.30 eV or more and -3.30 eV or less, since this can suppress an increase in the driving voltage, this is preferable. Note that, as the substance having electron transport properties used in the third region, it is preferable to use a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0208] Specific examples of the substance having an electron transport property that can be used in the third region include diquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA), 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine (abbreviation: HATNA-F6), perylene tetracarboxylic acid derivatives such as 3,4,9,10-perylene tetracarboxylic diimide (abbreviation: PTCDI) and 3,4,9,10-perylene tetracarboxyl-bis-benzimidazole (abbreviation: PTCBI), (C60-Ih)[5,6]fullerene (abbreviation: C60), and (C70-D5h)[5,6]fullerene (abbreviation: C70). Also, a compound having a heterophane skeleton, which is a cyclophane skeleton containing a hetero ring, can be used, and as the compound, for example, a phthalocyanine compound such as phthalocyanine (abbreviation: HPc) can be used. Also, metal phthalocyanines having copper, zinc, cobalt, iron, chromium, nickel, etc., such as copper phthalocyanine (abbreviation: CuPc), zinc phthalocyanine (abbreviation: ZnPc), cobalt phthalocyanine (abbreviation: CoPc), iron phthalocyanine (abbreviation: FePc), tin phthalocyanine (abbreviation: SnPc), tin oxide phthalocyanine (abbreviation: SnOPc), titanium oxide phthalocyanine (abbreviation: TiOPc), vanadium oxide phthalocyanine (abbreviation: VOPc), and derivatives thereof can be used. Also preferred are metal complexes of the phthalocyanine series, such as, in particular, copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine.

[0209] The film thickness of the third region is preferably 1 nm or more and 10 nm or less, and more preferably 2 nm or more and 5 nm or less.

[0210] A light-emitting device of one embodiment of the present invention having the above-described structure can be a light-emitting device with good characteristics even when subjected to processing by a photolithography method involving exposure to the air or exposure to the air before the formation of the second electrode.

[0211] (Embodiment 2) In this embodiment, a light-emitting device according to one embodiment of the present invention will be described in detail.

[0212] 1 is a schematic diagram of a light-emitting device 130 of one embodiment of the present invention. The light-emitting device 130 has a first electrode 101 provided over an insulator 100, and an organic compound layer 103 between the first electrode 101 and a second electrode 102. As described in Embodiment 1, the organic compound layer 103 includes a plurality of light-emitting units (a first light-emitting unit 501 and a second light-emitting unit 502 in FIG. 1) and an intermediate layer 116.

[0213] The first light-emitting unit 501 has at least a first light-emitting layer 113_1, and the second light-emitting unit 502 has at least a second light-emitting layer 113_2. The first light-emitting layer 113_1 and the second light-emitting layer 113_2 are layers containing a light-emitting substance, and emit light when a voltage is applied between the first electrode 101 and the second electrode 102.

[0214] 1, the first light-emitting unit 501 preferably has functional layers such as a hole injection layer 111, a first hole transport layer 112_1, and a first electron transport layer 114_1 in addition to the layers described above. In addition, the first light-emitting unit 501 may include functional layers other than the functional layers described above, such as an electron blocking layer and an exciton blocking layer. Conversely, any of the layers described above may not be provided.

[0215] 1, in addition to the layers described above, the second light-emitting unit 502 preferably has functional layers such as a second hole transport layer 112_2, a second electron transport layer 114_2, and an electron injection layer 115. In addition, the second light-emitting unit 502 may include functional layers other than the functional layers described above, such as a hole blocking layer, an electron blocking layer, and an exciton blocking layer. Conversely, any of the layers described above may not be provided.

[0216] The intermediate layer 116 has at least a first region 119, a third region 118, and a second region 117 from the anode (first electrode 101 in FIG. 1) side. The first region 119 is a region including an organic compound (first organic compound) having a first π-electron-deficient heteroaromatic ring having a metal or metal oxide and an electron-donating group, and an organic compound (second organic compound) having a second π-electron-deficient heteroaromatic ring, as described in the first embodiment. The second region 117 is a layer that generates charges by applying a voltage. The second region 117 is preferably a layer including an organic compound having a hole-transporting property and a substance having an electron-accepting property for the organic compound. The third region 118 is a layer made of a material having an electron-transporting property and a specific LUMO level, and the third region is provided to reduce the driving voltage of the light-emitting device. Also, a decrease in the reliability of the light-emitting device can be suppressed. Also, the light-emitting efficiency of the light-emitting device can be improved.

[0217] The specific configurations of first region 119, second region 117 and third region 118 have been described in detail in the first embodiment, so repeated description will be omitted.

[0218] In this embodiment, it is preferable that the first electrode 101 is an electrode including an anode, and the second electrode 102 is an electrode including a cathode. The first electrode 101 and the second electrode 102 may be formed as a single layer structure or a laminated structure. In the case of a laminated structure, a layer in contact with the organic compound layer 103 functions as an anode or a cathode. In the case of an electrode having a laminated structure, there is no restriction on the work function of layers other than the layer in contact with the organic compound layer 103, and materials may be selected according to required characteristics such as resistance value, ease of processing, reflectance, light transmittance, and stability.

[0219] 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). Specific examples include indium oxide-tin oxide (ITO), indium oxide-tin oxide containing silicon or silicon oxide (ITSO), indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metals or oxide films thereof are usually formed by a sputtering method, but may be formed by applying a sol-gel method or the like. As an example of a method for forming indium oxide-zinc oxide, a method for forming indium oxide-zinc oxide by a sputtering method using a target in which 1 to 20 wt % of zinc oxide is added to indium oxide may be used. Indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide. Other materials used for the anode include, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), titanium (Ti), aluminum (Al), or nitrides of metal materials (for example, titanium nitride). A layer of these laminated materials may also be used as the anode. For example, a film laminated in the order of Al, Ti, and ITSO on Ti is preferable because it has a good reflectance, is highly efficient, and can achieve high resolution of several thousand ppi. Alternatively, graphene can also be used as a material used for the anode. In addition, by using a composite material capable of forming the hole injection layer 111 described later as a layer in contact with the anode (typically a hole injection layer), it becomes possible to select an electrode material regardless of the work function.

[0220] The hole injection layer 111 is provided in contact with the anode and has a function of facilitating injection of holes into the organic compound layer 103. The hole injection layer 111 can be formed of a phthalocyanine-based compound or complex compound such as phthalocyanine (abbreviation: HPc) or copper phthalocyanine (abbreviation: CuPc), an aromatic amine compound such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB) or 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / (polystyrenesulfonic acid) (abbreviation: PEDOT / PSS).

[0221] The hole injection layer 111 may be formed of a substance having electron acceptor properties. As the substance having electron acceptor properties, an organic compound having an electron-withdrawing group (such as a halogen group or a cyano group) can be used, and examples of the substance include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile, and the like. In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and preferred. Radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group, a cyano group, etc.) [3] are preferred because they have a very high electron-accepting property, and specific examples thereof include α,α',α''-1,2,3-cyclopropane triylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropane triylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropane triylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. As the substance having electron acceptor properties, in addition to the organic compounds described above, transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, and manganese oxide can be used.

[0222] In addition, the hole-injection layer 111 is preferably formed using a composite material containing the above-mentioned material having an electron acceptor property and an organic compound having a hole-transport property.

[0223] As the organic compound having a hole transporting property used in the composite material, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that the organic compound having a hole transporting property used in the composite material is preferably 1×10 -6 cm 2 It is preferable that the organic compound has a hole mobility of 1000 nm or more / Vs. The organic compound having hole transport properties used in the composite material is preferably a compound having a condensed aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the condensed aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, etc. are preferable. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton in the ring is preferable, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed to the above rings is preferable.

[0224] Such organic compounds having hole transport properties preferably have any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the organic compounds may be aromatic amines having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the organic compounds having hole transport properties are substances having an N,N-bis(4-biphenyl)amino group, because this allows the manufacture of a light-emitting device with a long life.

[0225] Specific examples of organic compounds having hole transport properties as described above include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophene-4-yl)phenyl]-4-amino-p-terphenyl ]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβ NB-03), 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl] 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)furan-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N- Bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(biphenyl-4-yl)-N-(9,9-Dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4' -[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'- Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluorene-2-amine (abbreviation: PCBBiF), N,N-bis( 9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, etc. can be mentioned.

[0226] In addition, as a material having hole transport properties, other aromatic amine compounds such as 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), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B) can also be used.

[0227] By forming the hole injection layer 111, the hole injection property is improved, and a light emitting device with a low driving voltage can be obtained.

[0228] Among substances having an electron acceptor property, an organic compound having an electron acceptor property is an easy-to-use material because it can be easily evaporated and formed into a film.

[0229] The hole transport layer 112 is formed by including an organic compound having a hole transport property. -6 cm 2 It is preferable that the hole mobility is 1 / Vs or more.

[0230] Examples of the material having the hole transporting property include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluorene]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluorene-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'- (9-Phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), Compounds with aromatic amine skeletons such as 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)phenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and 4,4'-di(N-carbazolyl)phenylamine (abbreviation: PCBASF) bazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(biphenyl-3-yl)-9'-(biphenyl-4-yl)-9H,9'H-3,3'-Bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: BisβNCz), 9-( 2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-4-yl-3,3'-9H,9'H- Bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)- Compounds having a carbazole skeleton such as 9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylen-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, and 9-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]phenanthrene (abbreviation: PcPPn), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compounds include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-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-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. Note that the substances exemplified as the materials having hole transport properties used for the composite material of the hole injection layer 111 can also be suitably used as the material for forming the hole transport layer 112.

[0231] The light-emitting layer 113 (light-emitting layer 113_1, light-emitting layer 113_2) is a layer containing a light-emitting material, and preferably contains a light-emitting material and a host material. The light-emitting layer may contain other materials at the same time. Alternatively, the light-emitting layer may be a laminate of layers having different composition ratios.

[0232] The luminescent material may be a fluorescent material, a phosphorescent material, a material exhibiting thermally activated delayed fluorescence (TADF), or any other luminescent material.

[0233] Examples of materials that can be used as the fluorescent substance in the light-emitting layer include the following: In addition, fluorescent substances other than these can also be used.

[0234] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis(N,N',N'-triphenyl-1,4-phenylenediamine) (abbreviation: DPABPA), N,9 -Diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N'''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA) , 9,10-bis(biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyrazol-2-yl)-1,1-diphenylquinacridone (abbreviation: DPQd), DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation Name: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB),6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyrene-diyl)bis[(6-phenylbenzo[b ]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, condensed aromatic diamine compounds such as pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 are preferred because they have high hole trapping properties and excellent luminous efficiency or reliability.

[0235] In addition, 5,9-diphenyl-5,9-diaza-13b-boranaphtho[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]phenazaborin-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]phenazaborin-7-amine (abbreviation: DABNA3), Amine (abbreviation: DPhA-tBu4DABNA), 2,12-di(tert-butyl)-N,N,5,9-tetra(4-tert-butylphenyl)-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine-7-amine (abbreviation: tBuDPhA-tBu4DABNA), 2,12-di(tert-butyl)-5,9-di(4-tert-butylphenyl)-7-methyl-5H,9H-[1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: Me-tBu4DABNA), N 7 ,N 7 ,N 13 ,N 13 Condensed heteroaromatic compounds containing nitrogen and boron, such as 5,9,11,15-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]phenazaborine-7,13-diamine (abbreviation: ν-DABNA) and 2-(4-tert-butylphenyl)benz[5,6]indolo[3,2,1-jk]benzo[b]carbazole (abbreviation: tBuPBibc), in particular compounds having a diaza-boranaphtho-anthracene skeleton, can be suitably used because they have a narrow emission spectrum and can emit blue light with good color purity.

[0236] In addition to these, 9,10,11-tris[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-G), 9,11-bis[3,6-bis(1,1-dimethylethyl)-9H-carbazolyl-9-yl]-2,5,15,18-tetrakis(1,1-dimethylethyl)indolo[3,2,1-de]indolo[3',2',1':8,1][1,4]benzazaborino[2,3,4-kl]phenazaborine (abbreviation: BBCz-Y) and the like can be preferably used.

[0237] When a phosphorescent material is used as the light-emitting material in the light-emitting layer, examples of materials that can be used include the following.

[0238] Organometallic iridium compounds with 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) (abbreviation: [Ir(mpptz-dmp)3]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]). complexes, organometallic iridium complexes with 1H-triazole skeletons such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), fac-tris[1-( 2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN3} organometallic iridium complexes with an imidazole skeleton, such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), and organometallic complexes with a benzimidazolidene skeleton, such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ] Organometallic iridium complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as FIracac), are examples of such compounds that exhibit blue phosphorescence and have a peak emission wavelength in the range of 450 nm to 520 nm.

[0239] In addition, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6- Organometallic iridium complexes having a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]) and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]); organometallic iridium complexes having a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]); 2’) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ )iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’)iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3 -Methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl In addition to organometallic iridium complexes having a pyridine skeleton such as [2-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy)]), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium (abbreviation: [Ir(ppy)2(mdppy)]), rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]) can be mentioned. These are compounds that mainly exhibit green phosphorescence and have emission peaks in the wavelength range of 500 nm to 600 nm. Note that organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are remarkably excellent in reliability and luminous efficiency.

[0240] In addition, organometallic iridium complexes having a pyrimidine skeleton, such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]); Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinate)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinate)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’Organometallic iridium compounds with pyridine skeletons such as (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III) and (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). In addition to iridium complexes, platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: PtOEP), tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]) are examples of rare earth metal complexes. These are compounds that exhibit red phosphorescence and have a peak emission in the wavelength range from 600 nm to 700 nm. In addition, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity.

[0241] In addition to the above-mentioned phosphorescent compounds, known phosphorescent compounds may be selected and used.

[0242] TADF materials include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also included are metal-containing porphyrins including magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), palladium (Pd), etc. Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP), which are shown in the following structural formulas.

[0243] [ka]

[0244] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), Heterocyclic compounds having one or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron deficient heteroaromatic ring, the pyridine skeleton, the diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and the triazine skeleton are preferred because they are stable and reliable. In particular, the benzofuropyrimidine skeleton, the benzothienopyrimidine skeleton, the benzofuropyrazine skeleton, and the benzothienopyrazine skeleton are preferred because they have high electron acceptor properties and good reliability. In addition, among the skeletons having a π-electron rich heteroaromatic ring, the acridine skeleton, the phenoxazine skeleton, the phenothiazine skeleton, the furan skeleton, the thiophene skeleton, and the pyrrole skeleton are preferred because they are stable and reliable.In addition, the furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. In addition, the pyrrole skeleton is particularly preferably an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, or a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because 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 strong, and the energy difference between the S1 level and the T1 level is small, so that thermally activated delayed fluorescence can be efficiently obtained. In addition, an aromatic ring to which an electron-withdrawing group such as a cyano group is bonded may be used instead of the π-electron-deficient heteroaromatic ring. In addition, an aromatic amine skeleton, a phenazine skeleton, or the like can be used as the π-electron-rich skeleton. In addition, examples of the π-electron-deficient skeleton that can be used include 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 having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0245] [ka]

[0246] TADF materials are materials that have a small difference between the S1 and T1 levels and have the function of converting triplet excitation energy to singlet excitation energy by reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy by a small amount of thermal energy (reverse intersystem crossing), and singlet excitation states can be generated efficiently. In addition, triplet excitation energy can be converted into light emission.

[0247] In addition, exciplexes (also called exciplexes), which form an excited state with two types of substances, have an extremely small difference between the S1 level and the T1 level and function as TADF materials that can convert triplet excitation energy into singlet excitation energy.

[0248] As an index of the T1 level, a phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K) may be used. For a TADF material, when a tangent line is drawn at the base of the short wavelength side of the fluorescence spectrum, and the energy of the wavelength of the extrapolated line is defined as the S1 level, and a tangent line is drawn at the base of the short wavelength side of the phosphorescence spectrum, and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between the S1 level and the T1 level is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0249] In addition, when a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0250] As the host material of the light-emitting layer, various carrier transporting materials such as a material having an electron transporting property and / or a material having a hole transporting property, or the above-mentioned TADF material can be used.

[0251] As the material having hole transport properties, an organic compound having an amine skeleton, a π-electron-rich heteroaromatic ring skeleton, etc. is preferable. As the π-electron-rich heteroaromatic ring, a condensed aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton in the ring is preferable, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is further condensed to the above is preferable.

[0252] Such organic compounds having hole transport properties preferably have any of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton. In particular, the organic compounds may be aromatic amines having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the organic compounds having hole transport properties are substances having an N,N-bis(4-biphenyl)amino group, because this allows the manufacture of a light-emitting device with a long life.

[0253] Examples of such organic compounds include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PC Aromatic amines such as 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF) Compounds with a carbazole skeleton, such as 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), and 9,9'-diphenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCP), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of the compounds include compounds having a thiophene skeleton such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-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-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton or compounds having a carbazole skeleton are preferable because they have good reliability, high hole transportability, and contribute to reducing the driving voltage. In addition, the organic compounds listed as examples of materials having hole transportability in the hole transport layer can also be used.

[0254] Examples of materials having electron transport properties include metal complexes such as bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring. Examples of organic compounds having a π-electron-deficient heteroaromatic ring skeleton include organic compounds containing a heteroaromatic ring having an azole skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, organic compounds containing a heteroaromatic ring having a diazine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton.

[0255] Among them, organic compounds containing a heteroaromatic ring having a diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferable because of their good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. In addition, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, and benzothienopyrazine skeleton are preferable because of their high electron acceptor properties and good reliability.

[0256] 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-oxadiazole- Organic compounds with an azole skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), )phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), bathophenanthroline (abbreviation: BPhen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-[3-(2-triphenylenyl)phenyl]-1,10 -phenanthroline (abbreviation: mTpPPhen), 2-phenyl-9-(2-triphenylenyl)-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: PnNPhen), 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), and other organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 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 (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[4-(3,6-diphenyl 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNf pr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidinyl 4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl-3-yl]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation :2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine}(abbreviation:2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine(abbreviation:6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine(abbreviation:2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol Organic compounds with diazine skeletons such as 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 2-(biphenyl-4-yl)-4-phenyl-6-(9,9'-spirobi[9H-fluoren]-2-yl)-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d ]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole Rubazol (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6- Diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylindolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylen-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3 Examples of the organic compounds include organic compounds containing heteroaromatic rings having a triazine skeleton, such as -[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn) and 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn). In addition, organic compounds containing heteroaromatic rings having a diazine skeleton, organic compounds containing heteroaromatic rings having a pyridine skeleton, and organic compounds containing heteroaromatic rings having a triazine skeleton are preferred because of their good reliability. 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 and contribute to reducing the driving voltage.

[0257] In addition, organic compounds having bipolar properties such as 3,6-bis(diphenylamino)-9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9H-carbazole (abbreviation: DACT-II) and 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) can also be used.

[0258] As a TADF material that can be used as a host material, the same TADF materials listed above can be used. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy by reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby increasing the light-emitting efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor.

[0259] This is very effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0260] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest energy absorption band of the fluorescent material, because this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0261] In addition, in order to efficiently generate singlet excitation energy from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. In addition, it is preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. For this purpose, it is preferable that the fluorescent material has a protective group around the luminophore (skeleton causing light emission) of the fluorescent material. As the protective group, a substituent having no π bond is preferable, and a saturated hydrocarbon is preferable, specifically, an alkyl group having 3 to 10 carbon atoms, a substituted or unsubstituted cycloalkyl group having 3 to 10 carbon atoms, and a trialkylsilyl group having 3 to 10 carbon atoms are mentioned, and it is more preferable that there are a plurality of protective groups. Since a substituent having no π bond has poor function of transporting carriers, the distance between the TADF material and the luminophore of the fluorescent material can be increased without affecting carrier transport or carrier recombination. Here, the luminophore refers to an atomic group (skeleton) causing light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a condensed aromatic ring or a condensed heteroaromatic ring. Examples of such 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, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton are preferred because they have a high fluorescence quantum yield.

[0262] When a fluorescent emitting material is used as the emitting material, a material having an anthracene skeleton is suitable as the host material. When a material having an anthracene skeleton is used as the host material of the fluorescent emitting material, it is possible to realize an emitting layer having both good luminous efficiency and durability. As a material having an anthracene skeleton to be used as the host material, a material having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferable because it is chemically stable. In addition, when the host material has a carbazole skeleton, it is preferable because the injection and transport properties of holes are improved, but when it contains a benzocarbazole skeleton in which a benzene ring is further condensed to carbazole, the HOMO level is shallower by about 0.1 eV than that of a host material having a carbazole skeleton, making it easier for holes to enter, which is more preferable. In particular, when the host material contains a dibenzocarbazole skeleton, it is preferable because the HOMO level is shallower by about 0.1 eV than that of a host material having a carbazole skeleton, making it easier for holes to enter, and it also has excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). 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-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-[4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'- 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,βADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)benzo Zo[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), etc. In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferred choices because they show very good properties.

[0263] The host material may be a mixture of a plurality of substances, and when a mixture of host materials is used, it is preferable to mix a material having an electron transporting property with a material having a hole transporting property. By mixing a material having an electron transporting property with a material having a hole transporting property, the transporting property of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. The weight ratio of the content of the material having a hole transporting property to the material having an electron transporting property may be 1:19 to 19:1 (material having a hole transporting property:material having an electron transporting property).

[0264] A phosphorescent material can be used as a part of the mixed material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as a light-emitting material.

[0265] In addition, these mixed materials may form an exciplex. It is preferable to select a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest energy absorption band of the light-emitting material, because this makes energy transfer smooth and allows efficient light emission. In addition, the use of this structure is preferable because the driving voltage is reduced.

[0266] At least one of the materials forming the exciplex may be a phosphorescent material, which allows the triplet excitation energy to be efficiently converted into singlet excitation energy by reverse intersystem crossing.

[0267] As a combination of materials that efficiently form an exciplex, it is preferable that the HOMO level of the material having hole transport properties is equal to or higher than the HOMO level of the material having electron transport properties. It is also preferable that the LUMO level of the material having hole transport properties is equal to or higher than the LUMO level of the material having electron transport properties. The LUMO level and HOMO level of the material can be derived from the electrochemical properties (reduction potential and oxidation potential) of the material measured by cyclic voltammetry (CV) measurement.

[0268] The formation of an exciplex can be confirmed, for example, by comparing the emission spectrum of a material having hole transport properties, the emission spectrum of a material having electron transport properties, and the emission spectrum of a mixed film obtained by mixing these materials, and observing the phenomenon that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectrum of each material (or has a new peak on the longer wavelength side). Alternatively, the formation of an exciplex can be confirmed by comparing 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 obtained by mixing these materials, and observing the difference in transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component than the transient PL lifetime of each material, or the proportion of delayed components becoming larger. The above-mentioned transient PL may also be read as transient electroluminescence (EL). That is, the formation of an exciplex can also 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 obtained by mixing these materials, and observing the difference in transient response.

[0269] In addition, the light-emitting layer 113 preferably contains a third organic compound having a third π-electron-deficient heteroaromatic ring as a host material. In addition, the third π-electron-deficient heteroaromatic ring is preferably the same as the second π-electron-deficient heteroaromatic ring of the second organic compound contained in the first layer of the intermediate layer. In addition, it is more preferable that the third organic compound is the same as the second organic compound.

[0270] The electron transport layer 114 (the first electron transport layer 114_1 and the second electron transport layer 114_2) is a layer containing a material having an electron transport property. The material having the electron transport property is a material having an electron mobility of 1×10 -7 cm 2 / Vs or more, preferably 1×10 -6 cm 2A substance having an electron mobility of 100 / Vs or more is preferable. Note that, other substances can be used as long as they have a higher transportability of electrons than holes. Note that, as the organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferable. As the organic compound having a π-electron-deficient heteroaromatic ring, for example, it is preferable to use one or more of an organic compound having a heteroaromatic ring with an azole skeleton, an organic compound having a heteroaromatic ring with a pyridine skeleton, an organic compound having a heteroaromatic ring with a diazine skeleton, and an organic compound having a heteroaromatic ring with a triazine skeleton.

[0271] As the organic compound having electron transport properties that can be used in the first electron transport layer 114_1 and the second electron transport layer 114_2, the organic compound that can be used as the organic compound having electron transport properties in the first light-emitting layer 113_1 and the second light-emitting layer 113_2 can be used in the same way. Among them, organic compounds containing a heteroaromatic ring having a diazine skeleton or an organic compound containing a heteroaromatic ring having a pyridine skeleton, and an organic compound containing a heteroaromatic ring having a triazine skeleton are preferable because they have good reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing the driving voltage. Among them, organic compounds having a phenanthroline skeleton such as mTpPPhen, PnNPhen, and mPPhen2P are preferable, and organic compounds having a phenanthroline dimer structure such as mPPhen2P are more preferable because they have excellent stability.

[0272] In addition, the first electron transport layer preferably contains an organic compound having an acid dissociation constant pKa of less than 4 and having electron transport properties.

[0273] The first electron transport layer 114_1 and the second electron transport layer 114_2 may have a laminated structure. When the second electron transport layer 114_2 has a laminated structure, a layer in contact with the second light-emitting layer 113_2 may function as a hole-blocking layer. When the electron transport layer in contact with the light-emitting layer is made to function as a hole-blocking layer, it is preferable to use a material whose HOMO level is 0.5 eV or more deeper than the HOMO level of the material contained in the light-emitting layer.

[0274] In addition, the electron transport layer sandwiched between the light-emitting layer and the intermediate layer preferably contains an organic compound having a π-electron-deficient heteroaromatic ring, and the organic compound having the π-electron-deficient heteroaromatic ring is different from the organic compound having the π-electron-deficient heteroaromatic ring contained in the light-emitting layer described above. That is, in FIG. 1, the first electron transport layer 114_1 preferably contains a fourth organic compound having a π-electron-deficient heteroaromatic ring, and the fourth organic compound is different from the third organic compound having a third π-electron-deficient heteroaromatic ring contained in the first light-emitting layer 113_1.

[0275] Between the electron transport layer closest to the second electrode 102 (the second electron transport layer 114_2 in FIG. 1) and the second electrode 102, a layer containing an alkali metal or an alkaline earth metal or a compound thereof, such as lithium oxide (Li2O), lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), or 8-hydroxyquinolinato-lithium (abbreviation: Liq), may be provided as the electron injection layer 115. The electron injection layer 115 may be a layer made of a substance having an electron transport property containing an alkali metal or an alkaline earth metal or a compound thereof, or an electride may be used. Examples of the electride include a substance in which electrons are added at a high concentration to a mixed oxide of calcium and aluminum.

[0276] The electron-injecting layer 115 may use any of the above substances alone, or may contain any of the above substances in a layer made of a substance having an electron-transporting property.

[0277] Note that a layer containing a fluoride of the alkali metal or alkaline earth metal in a substance having an electron transporting property (preferably an organic compound having a bipyridine skeleton) at a concentration at which the fluoride is in a microcrystalline state or higher (50 wt % or higher) can be used as the electron injection layer 115. Since this layer has a low refractive index, it is possible to provide a light-emitting device with better external quantum efficiency.

[0278] The second electrode 102 is an electrode including a cathode. The second electrode 102 may have a laminated structure, in which case the layer in contact with the organic compound layer 103 functions as the cathode. As a material for forming the cathode, a metal, an alloy, an electrically conductive compound, a mixture thereof, or the like having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such a cathode material 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), and strontium (Sr), and alloys (MgAg, AlLi) and compounds (lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), etc.) containing these, rare earth metals such as europium (Eu), ytterbium (Yb), and alloys containing these, etc. However, by providing the 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 can be used as the cathode regardless of the magnitude of the work function.

[0279] In addition, when the second electrode 102 is formed from a material that is transparent to visible light, a light-emitting device can be formed that emits light from the second electrode 102 side, and when the first electrode 101 is formed from a material that is transparent to visible light, a light-emitting device can be formed that emits light from the first electrode 101 side.

[0280] These conductive materials can be formed into a film by a dry method such as a vacuum deposition method or a sputtering method, an inkjet method, a spin coating method, etc. Also, they may be formed by a wet method using a sol-gel method, or may be formed by a wet method using a paste of a metal material.

[0281] In addition, various methods can be used for forming the organic compound layer 103, regardless of whether it is a dry method or a wet method. For example, a vacuum deposition method, a gravure printing method, an offset printing method, a screen printing method, an inkjet method, a spin coating method, or the like may be used.

[0282] Moreover, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0283] 1, a light-emitting device having two light-emitting units has been described, but the present invention can be applied to a light-emitting device having three or more light-emitting units stacked together. As in the light-emitting device according to the present embodiment, by disposing a plurality of light-emitting units between a pair of electrodes and separating them with an intermediate layer 116, it is possible to realize an element that can emit light with high luminance while keeping the current density low and has a long life. In addition, it is possible to realize a light-emitting device that can be driven at a low voltage and consumes low power.

[0284] In addition, by making the emission colors of the respective light-emitting units different, it is possible to obtain light emission of a desired color from the light-emitting device as a whole. For example, in a light-emitting device having two light-emitting units, it is possible to obtain a light-emitting device that emits white light as a whole by obtaining red and green emission colors from the first light-emitting unit and blue emission color from the second light-emitting unit.

[0285] In addition, each layer and electrode such as the organic compound layer 103, the first light-emitting unit 501, the second light-emitting unit 502, and the charge generation layer can be formed by using, for example, a deposition method (including a vacuum deposition method), a droplet discharge method (also called an ink-jet method), a coating method, a gravure printing method, etc. In addition, they may contain a low molecular weight material, a medium molecular weight material (including an oligomer and a dendrimer), or a polymer material.

[0286] FIG. 2 shows two adjacent tandem light-emitting devices (light-emitting device 130c, light-emitting device 130d) fabricated by photolithography.

[0287] The light-emitting device 130c has an organic compound layer 103c between the first electrode 101c and the second electrode 102 on the insulating layer 175. The organic compound layer 103c has a configuration in which a first light-emitting unit 501c and a second light-emitting unit 502c are laminated with an intermediate layer 116c sandwiched therebetween. Although an example in which two light-emitting units are laminated is shown in FIG. 2, a configuration in which three or more light-emitting units are laminated may also be used. The first light-emitting unit 501c has a hole injection layer 111c, a first hole transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron transport layer 114c_1. The intermediate layer 116c has a second region 117c, a third region 118c, and a first region 119c. The second light-emitting unit 502c includes a second hole-transporting layer 112c_2, a second light-emitting layer 113c_2, a second electron-transporting layer 114c_2, and an electron-injecting layer 115.

[0288] The light-emitting device 130d has an organic compound layer 103d between the first electrode 101d and the second electrode 102 on the insulating layer 175. The organic compound layer 103d has a configuration in which a first light-emitting unit 501d and a second light-emitting unit 502d are stacked with an intermediate layer 116d sandwiched therebetween. Although an example in which two light-emitting units are stacked is shown in FIG. 2, a configuration in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501d has 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 has a second region 117d, a third region 118d, and a first region 119d. The second light-emitting unit 502d includes a second hole-transporting layer 112d_2, a second light-emitting layer 113d_2, a second electron-transporting layer 114d_2, and an electron-injecting layer 115.

[0289] In the light emitting devices 130c and 130d, the intermediate layers 116c and 116d preferably have the same configuration as described in the first embodiment.

[0290] It is preferable that the electron injection layer 115 and the second electrode 102 are a continuous layer shared by the light emitting device 130c and the light emitting device 130d. The organic compound layer 103c and the organic compound layer 103d other than the electron injection layer 115 are processed by photolithography after the second electron transport layer 114c_2 and the second electron transport layer 114d_2 are formed, respectively, and are therefore independent of each other. The end (outline) of the organic compound layer 103c other than the electron injection layer 115 is processed by photolithography, so that it roughly coincides with the direction perpendicular to the substrate. The end (outline) of the organic compound layer 103d other than the electron injection layer 115 is processed by photolithography, so that it roughly coincides with the direction perpendicular to the substrate.

[0291] In addition, since the organic compound layer 103c is processed by photolithography, a gap d exists between the organic compound layer 103c and the organic compound layer 103d. In addition, since the organic compound layer is processed by photolithography, the distance between the first electrode 101c and the first electrode 101d can be made smaller than that in the case of performing mask deposition, and can be set to 0.5 μm or more and 5 μm or less.

[0292] A light-emitting device according to one embodiment of the present invention having the above-described structure can have high current efficiency and high reliability, and an increase in driving voltage can be suppressed.

[0293] Note that the light-emitting device of one embodiment of the present invention is particularly suitable for a light-emitting device that has undergone a photolithography process; however, even a light-emitting device manufactured without undergoing a photolithography process has high stability against the atmosphere, which improves yield and contributes to cost reduction because it is not necessary to control the atmosphere more strictly during the manufacturing process.

[0294] (Embodiment 3) In this embodiment, a mode in which a light-emitting device of one embodiment of the present invention is used as a display element of a display device will be described.

[0295] As shown in FIGS. 3A and 3B, a plurality of light emitting devices 130 are formed on an insulating layer 175 to constitute a display device.

[0296] The display device has a pixel portion 177 in which a plurality of pixels 178 are arranged in a matrix. The pixel 178 has a sub-pixel 110R, a sub-pixel 110G, and a sub-pixel 110B.

[0297] In this specification and the like, when describing matters common to, for example, the subpixels 110R, 110G, and 110B, they may be referred to as subpixels 110. When describing matters common to other components distinguished by alphabets, they may be described using symbols without the alphabets.

[0298] The sub-pixel 110R emits red light, the sub-pixel 110G emits green light, and the sub-pixel 110B emits blue light. This allows an image to be displayed in the pixel section 177. In the present embodiment, sub-pixels of three colors, red (R), green (G), and blue (B), are described as an example, but combinations of sub-pixels of other colors may be used. The number of sub-pixels is not limited to three, and may be four or more. Examples of the four sub-pixels include 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 R, G, B, and infrared (IR).

[0299] 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.

[0300] 3A shows an example in which subpixels of different colors are arranged side by side in the X direction, and subpixels of the same color are arranged side by side in the Y direction. Note that subpixels of different colors may be arranged side by side in the Y direction, and subpixels of the same color may be arranged side by side in the X direction.

[0301] A connection portion 140 and a region 141 may be provided outside the pixel portion 177. The region 141 is provided between the pixel portion 177 and the connection portion 140. The region 141 is provided with an organic compound layer 103. In addition, the connection portion 140 is provided with a conductive layer 151C.

[0302] 3A shows an example in which the region 141 and the connection portion 140 are located on the right side of the pixel portion 177, but the positions of the region 141 and the connection portion 140 are not particularly limited. The region 141 and the connection portion 140 may be singular or plural.

[0303] Fig. 3(B) is an example of a cross-sectional view between dashed line A1-A2 in Fig. 3(A). As shown in Fig. 3(B), the display device has an insulating layer 171, a conductive layer 172 on the insulating layer 171, an insulating layer 173 on the insulating layer 171 and on the conductive layer 172, an insulating layer 174 on the insulating layer 173, and an insulating layer 175 on the insulating layer 174. The insulating layer 171 is provided on a substrate (not shown). An opening reaching the conductive layer 172 is provided in the insulating layer 175, the insulating layer 174, and the insulating layer 173, and a plug 176 is provided to fill the opening.

[0304] In the pixel section 177, the light emitting device 130 is provided on the insulating layer 175 and the plug 176. A protective layer 131 is provided so as to cover the light emitting device 130. The substrate 120 is bonded onto the protective layer 131 by a 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.

[0305] 3B shows multiple cross sections of the inorganic insulating layer 125 and the insulating layer 127, it is preferable that the inorganic insulating layer 125 and the insulating layer 127 are connected to one another when the display device is viewed from above. In other words, it is preferable that the insulating layer 127 is an insulating layer having an opening over the first electrode.

[0306] In FIG. 3B, the light emitting device 130 includes a light emitting device 130R, a light emitting device 130G, and a light emitting device 130B. The light emitting device 130R, the light emitting device 130G, and the light emitting device 130B emit light of different colors. For example, the light emitting device 130R can emit red light, the light emitting device 130G can emit green light, and the light emitting device 130B can emit blue light. The light emitting device 130R, the light emitting device 130G, or the light emitting device 130B may emit other visible light or infrared light.

[0307] The display device of one embodiment of the present invention can be, for example, a top emission type that emits light in a direction opposite to a substrate on which a light-emitting device is formed. Note that the display device of one embodiment of the present invention may be a bottom emission type.

[0308] The light-emitting device 130R has a configuration as shown in the first and second embodiments. The light-emitting device 130R also has a first electrode 101R (pixel electrode) consisting of a conductive layer 151R and a conductive layer 152R, a first EL layer 104R on the first electrode 101R, an organic compound layer (a second EL layer 105 on the first EL layer 104R), and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably located closer to the second electrode 102 (common electrode) than the light-emitting layer, and is preferably a hole blocking layer, a second electron transport layer, an electron injection layer, or a laminate of these. With such a configuration, damage to the light-emitting layer or active layer in the photolithography process can be suppressed, and good film quality and electrical characteristics can be expected.

[0309] The light-emitting device 130G has a configuration as shown in the embodiment 1 and the embodiment 2. The light-emitting device 130G also has a first electrode 101G (pixel electrode) composed of a conductive layer 151G and a conductive layer 152G, a first EL layer 104G on the first electrode 101G, a second EL layer 105 on the first EL layer 104G, and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably a hole blocking layer, a second electron transport layer, an electron injection layer, or a laminate of these layers.

[0310] The light-emitting device 130B has a configuration as shown in the embodiment 1 and the embodiment 2. The light-emitting device 130B has a first electrode 101B (pixel electrode) consisting of a conductive layer 151B and a conductive layer 152B, a first EL layer 104B on the first electrode 101B, a second EL layer 105 on the first EL layer 104B, and a second electrode 102 (common electrode) on the second EL layer 105. The second EL layer 105 is preferably a hole blocking layer, a second electron transport layer, an electron injection layer, or a laminate of these layers.

[0311] One of a pixel electrode (first electrode) and a common electrode (second electrode) of a light-emitting device functions as an anode, and the other functions as a cathode. In this embodiment, unless otherwise specified, the pixel electrode functions as an anode, and the common electrode functions as a cathode.

[0312] The first EL layer 104R, the first EL layer 104G, and the first EL layer 104B are independent in an island shape for each light-emitting device or for each light-emitting color. It is preferable that the first EL layer 104R, the first EL layer 104G, and the first EL layer 104B do not overlap each other. By providing the first EL layer 104 in an island shape for each light-emitting device 130, it is possible to suppress leakage current between adjacent light-emitting devices 130 even in a high-definition display device. This makes it possible to prevent crosstalk and realize a display device with extremely high contrast. In particular, it is possible to realize a display device with high current efficiency at low luminance.

[0313] The island-shaped first EL layer 104 can be formed by depositing an EL film and processing the EL film by using a photolithography method.

[0314] 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. For example, in the example shown in FIG. 3B, the first electrode 101 of the light-emitting device 130 has a stacked structure of a conductive layer 151 provided on the insulating layer 171 side and a conductive layer 152 provided on the organic compound layer side.

[0315] For example, a metal material can be used as the conductive layer 151. Specifically, 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 containing appropriate combinations of these metals can also be used.

[0316] The conductive layer 152 can be made of an oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon. 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, a work function of 4.0 eV or more, and therefore can be suitably used for the conductive layer 152.

[0317] The conductive layer 151 may have a stacked structure of multiple layers having different materials, and the conductive layer 152 may have a stacked structure of multiple layers having different materials. In this case, the conductive layer 151 may have a layer using a material that can be used for the conductive layer 152, such as a conductive oxide, or the conductive layer 152 may have a layer using a material that can be used for the conductive layer 151, such as a metal material. For example, when the conductive layer 151 has a stacked structure of two or more layers, a layer in contact with the conductive layer 152 can be a layer using a material that can be used for the conductive layer 152.

[0318] Note that the conductive layer 151 preferably has a tapered end. Specifically, the conductive layer 151 preferably has a tapered end with a taper angle of less than 90°. In this case, the conductive layer 152 provided along the side surface of the conductive layer 151 also has a tapered end. By making the side surface of the conductive layer 152 tapered, the coverage of the first EL layer 104 provided along the side surface of the conductive layer 152 can be improved.

[0319] In the display device of one embodiment of the present invention, since the light-emitting device 130 has the structure described in Embodiments 1 and 2, a light-emitting device that has excellent moisture resistance, water resistance, oxygen resistance, and chemical resistance, has a low driving voltage, and has high light-emitting efficiency can be provided.

[0320] Next, an example of a method for manufacturing a display device having the structure shown in FIG. 3A will be described with reference to FIGS.

[0321] [Production method example 1] The thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum deposition method, a pulsed laser deposition (PLD) method, an ALD method, or the like.

[0322] Furthermore, the thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed by wet film formation methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, or knife coating.

[0323] Furthermore, when processing the thin films that constitute the display device, they can be processed using, for example, a photolithography method.

[0324] In the photolithography method, the light used for exposure may be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. In addition, ultraviolet light, KrF laser light, ArF laser light, etc. may also be used. Exposure may also be performed by immersion exposure technology. Extreme ultraviolet (EUV) light or X-rays may also be used as the light used for exposure. An electron beam may also be used instead of the light used for exposure.

[0325] The thin film can be etched by dry etching, wet etching, sandblasting, or the like.

[0326] 4(A), 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.

[0327] The substrate may be a substrate having at least a heat resistance sufficient to withstand a subsequent heat treatment, such as a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, a single crystal semiconductor substrate made of silicon, silicon carbide, or the like, a polycrystalline semiconductor substrate, a compound semiconductor substrate made of silicon germanium, or the like, or an SOI substrate.

[0328] 4A, an opening reaching the conductive layer 172 is formed in the insulating layer 175, the insulating layer 174, and the insulating layer 173. Then, a plug 176 is formed to fill the opening.

[0329] 4A, a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, is formed on the plugs 176 and the insulating layer 175. The conductive film 151f can be made of, for example, a metal material.

[0330] 4A, a resist mask 191 is formed over the conductive film 151f. The resist mask 191 can be formed by applying a photosensitive material (photoresist) and then performing exposure and development.

[0331] 4B, for example, the conductive film 151f is removed from a region that does not overlap with the resist mask 191. As a result, the conductive layer 151 is formed.

[0332] 4(C), the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, for example.

[0333] Next, as shown in FIG. 4(D), an insulating film 156f, which will later become insulating layers 156R, 156G, 156B, and 156C, is formed on conductive layer 151R, conductive layer 151G, conductive layer 151B, conductive layer 151C, and insulating layer 175.

[0334] The insulating film 156f can be an inorganic insulating film such as an insulating oxide film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film, for example, a silicon oxynitride film.

[0335] Subsequently, as shown in FIG. 4(E), the insulating film 156f is processed to form an insulating layer 156R, an insulating layer 156G, an insulating layer 156B, and an insulating layer 156C.

[0336] Next, as shown in FIG. 5(A), a conductive film 152f is formed on the conductive layer 151R, the conductive layer 151G, the conductive layer 151B, the conductive layer 151C, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the insulating layer 156C, and the insulating layer 175.

[0337] The conductive film 152f may be, for example, a conductive oxide, or may be a multilayer film.

[0338] Subsequently, as shown in FIG. 5B, the conductive film 152f is processed to form a conductive layer 152R, a conductive layer 152G, a conductive layer 152B, and a conductive layer 152C.

[0339] 5(C), 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. Note that, as shown in FIG. 5(C), the organic compound film 103Rf is not formed on the conductive layer 152C.

[0340] Subsequently, as shown in FIG. 5(C), a sacrificial film 158Rf and a mask film 159Rf are formed.

[0341] 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.

[0342] The sacrificial film 158Rf is made of a film having high resistance to the processing conditions of the organic compound film 103Rf, specifically, a film having a high etching selectivity with respect to the organic compound film 103Rf. The mask film 159Rf is made of a film having a high etching selectivity with respect to the sacrificial film 158Rf.

[0343] The sacrificial film 158Rf and the mask film 159Rf are formed at a temperature lower than the heat-resistant temperature of the organic compound film 103Rf. The substrate temperature when forming the sacrificial film 158Rf and the mask film 159Rf is typically 100° C. or higher and 200° C. or lower, preferably 100° C. or higher and 150° C. or lower, and more preferably 100° C. or higher and 120° C. or lower.

[0344] The sacrificial film 158Rf and the mask film 159Rf are preferably made of a film that can be removed by wet etching or dry etching.

[0345] In addition, the sacrificial film 158Rf formed on and in contact with the organic compound film 103Rf is preferably formed using a formation method that causes less damage to the organic compound film 103Rf than the mask film 159Rf. For example, the ALD method (Atomic Layer Deposition method) or the vacuum deposition method is more preferable than the sputtering method.

[0346] The sacrificial film 158Rf and the mask film 159Rf may each be made of 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, for example.

[0347] The sacrificial film 158Rf and the mask film 159Rf may be made of, for example, a metal material such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, or tantalum, or an alloy material containing the metal material. In particular, it is preferable to use a low melting point material such as aluminum or silver. It is preferable to use a metal material capable of blocking ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf, since it is possible to suppress irradiation of ultraviolet rays during pattern exposure to the organic compound film 103Rf, and thus to suppress deterioration of the organic compound film 103Rf.

[0348] Furthermore, for 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), and indium tin oxide containing silicon can be used.

[0349] In addition, in the above metal oxide, an element M (M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) may be used instead of gallium.

[0350] For the sacrificial film 158Rf and the mask film 159Rf, it is preferable to use a semiconductor material such as silicon or germanium because it has a high affinity with the semiconductor manufacturing process, or a compound containing the above semiconductor material may be used.

[0351] Moreover, 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 preferable because it has higher adhesion to the organic compound film 103Rf than a nitride insulating film.

[0352] 5(C), a resist mask 190R is formed. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and then performing exposure and development.

[0353] The resist mask 190R is provided in a position overlapping with the conductive layer 152R. The resist mask 190R is preferably provided also in a position overlapping with the conductive layer 152C, which can prevent the conductive layer 152C from being damaged during the manufacturing process of the display device.

[0354] 5(D), a resist mask 190R is used to remove a portion of the mask film 159Rf to form a mask layer 159R. The mask layer 159R remains on the conductive layer 152R and the conductive layer 152C. The resist mask 190R is then removed. The mask layer 159R is used as a mask (also called a hard mask) to remove a portion of the sacrificial film 158Rf to form a sacrificial layer 158R.

[0355] By using the wet etching method, damage to the organic compound film 103Rf during 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 using the wet etching method, it is preferable to use an acid aqueous solution such as a developing solution, an alkaline aqueous solution such as a tetramethylammonium hydroxide (TMAH) aqueous solution, a chemical solution using dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture of these.

[0356] Furthermore, when dry etching is used in processing the sacrificial film 158Rf, deterioration of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0357] The resist mask 190R can be removed in the same manner as the resist mask 191.

[0358] 5(D), the organic compound film 103Rf is processed to form the organic compound layer 103R. For example, the mask layer 159R and the sacrificial layer 158R are used as a hard mask to remove a part of the organic compound film 103Rf to form the organic compound layer 103R.

[0359] 5D, a laminated structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R. Also, the conductive layer 152G and the conductive layer 152B are exposed.

[0360] The organic compound film 103Rf is preferably processed by anisotropic etching, particularly anisotropic dry etching, or wet etching may be used.

[0361] When dry etching is used, deterioration of the organic compound film 103Rf can be suppressed by not using an oxygen-containing gas as an etching gas.

[0362] Moreover, a gas containing oxygen may be used as the etching gas. When the etching gas contains oxygen, the etching speed can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching speed. This makes it possible to suppress damage to the organic compound film 103Rf. Furthermore, problems such as adhesion of reaction products generated during etching can be suppressed.

[0363] When using a dry etching method, it is preferable to use a gas containing one or more of H2, CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, or a group 18 element such as He or Ar as an etching gas. Alternatively, it is preferable to use a gas containing one or more of these elements and oxygen as an etching gas. Alternatively, oxygen gas may be used as an etching gas.

[0364] Subsequently, as shown in FIG. 6(A), an organic compound film 103Gf which will later become the organic compound layer 103G is formed.

[0365] The organic compound film 103Gf can be formed by the same method as that used for forming the organic compound film 103Rf, and can have the same configuration as the organic compound film 103Rf.

[0366] 6A, a sacrificial film 158Gf and a mask film 159Gf are formed in this order. Then, a resist mask 190G is formed. The material and the forming method 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 material and the forming method of the resist mask 190G are the same as those applicable to the resist mask 190R.

[0367] The resist mask 190G is provided in a position overlapping with the conductive layer 152G.

[0368] Then, as shown in FIG. 6B, a part of the mask film 159Gf is removed using a resist mask 190G to form a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. Then, the resist mask 190G is removed. Then, a part of the sacrificial film 158Gf is removed using the mask layer 159G as a mask to form a sacrificial layer 158G. Then, the organic compound film 103Gf is processed to form an organic compound layer 103G. Thereby, as shown in FIG. 6B, a laminated structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G. Also, the mask layer 159R and the conductive layer 152B are exposed.

[0369] Subsequently, as shown in FIG. 6(C), an organic compound film 103Bf is formed.

[0370] The organic compound film 103Bf can be formed by the same method as that used for forming the organic compound film 103Rf, and can have the same structure as the organic compound film 103Rf.

[0371] 6(C), a sacrificial film 158Bf and a mask film 159Bf are formed in this order. Then, a resist mask 190B is formed. The material and the forming method of the sacrificial film 158Bf and the mask film 159Bf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The material and the forming method of the resist mask 190B are the same as those applicable to the resist mask 190R.

[0372] The resist mask 190B is provided in a position overlapping with the conductive layer 152B.

[0373] 6(D), a resist mask 190B is used to remove a portion of the mask film 159Bf to form a mask layer 159B. The mask layer 159B remains on the conductive layer 152B. The resist mask 190B is then removed. The mask layer 159B is then used as a mask to remove a portion of the sacrificial film 158Bf to form a sacrificial layer 158B. The organic compound film 103Bf is then processed to form an organic compound layer 103B. For example, the mask layer 159B and the sacrificial layer 158B are used as hard masks to remove a portion of the organic compound film 103Bf to form the organic compound layer 103B.

[0374] 6D, a laminated structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B. Also, the mask layers 159R and 159G are exposed.

[0375] It is preferable that the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are perpendicular or approximately perpendicular to the surface on which they are formed. For example, it is preferable that the angle between the surface on which they are formed and these side surfaces is 60 degrees or more and 90 degrees or less.

[0376] As described above, the distance between two adjacent ones of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B formed by photolithography can be narrowed to 8 μm or less, 5 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. Here, the distance can be defined, for example, as the distance between two adjacent opposing ends of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In this way, by narrowing the distance between the island-shaped organic compound layers, a display device having high definition and a large aperture ratio can be provided. In addition, the distance between the first electrodes between adjacent light-emitting devices can also be narrowed, and can be, for example, 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. Note that the distance between the first electrodes between adjacent light-emitting devices is preferably 2 μm or more and 5 μm or less.

[0377] Subsequently, as shown in FIG. 7(A), it is preferable to remove the mask layers 159R, 159G, and 159B.

[0378] The mask layer removal process can be performed using the same method as the mask film processing process. In particular, by using a wet etching method, damage to the organic compound layer 103 during removal of the mask layer can be reduced compared to the case of using a dry etching method.

[0379] The mask layer may also be removed by dissolving it in a polar solvent such as water or alcohol, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0380] After removing the mask layer, a drying treatment may be performed to remove water adsorbed on the surface. For example, a heat treatment can be performed in an inert gas atmosphere or a reduced pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., and more preferably 70° C. to 120° C. A reduced pressure atmosphere is preferable because it allows drying at a lower temperature.

[0381] Subsequently, as shown in FIG. 7(B), an inorganic insulating film 125f is formed.

[0382] Subsequently, as shown in FIG. 7(C), an insulating film 127f, which will later become the insulating layer 127, is formed on the inorganic insulating film 125f.

[0383] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or more, 80°C or more, 100°C or more, or 120°C or more, and 200°C or less, 180°C or less, 160°C or less, 150°C or less, or 140°C or less.

[0384] As the inorganic insulating film 125f, it is preferable to form an insulating film having a thickness of 3 nm or more, 5 nm or more, or 10 nm or more and 200 nm or less, 150 nm or less, 100 nm or less, or 50 nm or less within the above substrate temperature range.

[0385] The inorganic insulating film 125f is preferably formed by, for example, the ALD method. By using the ALD method, damage during film formation can be reduced, and a film with high coverage can be formed, which is preferable. As the inorganic insulating film 125f, for example, an aluminum oxide film is preferably formed by the ALD method.

[0386] The insulating film 127f is preferably formed by using the above-mentioned wet film formation method. The insulating film 127f is preferably formed by using a photosensitive material, for example, by spin coating, and more specifically, is preferably formed by using a photosensitive resin composition containing an acrylic resin.

[0387] Subsequently, exposure is performed to expose a part of the insulating film 127f to visible light or ultraviolet light. The insulating layer 127 is formed in a region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C.

[0388] The width of the insulating layer 127 to be formed later can be controlled by the exposed region of the insulating film 127f. In this embodiment, the insulating layer 127 is processed so as to have a portion overlapping with the upper surface of the conductive layer 151.

[0389] The light used for exposure preferably contains i-line (wavelength 365 nm), and may contain at least one of g-line (wavelength 436 nm) and h-line (wavelength 405 nm).

[0390] Subsequently, as shown in FIG. 8(A), development is performed to remove the exposed area of ​​the insulating film 127f, thereby forming an insulating layer 127a.

[0391] 8(B), an etching process is performed using the insulating layer 127a as a mask to remove a part of the inorganic insulating film 125f and to thin the thickness of the sacrificial layers 158R, 158G, and 158B. As a result, the inorganic insulating layer 125 is formed under the insulating layer 127a. In addition, the surfaces of the thin parts of the sacrificial layers 158R, 158G, and 158B are exposed. In the following, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0392] The first etching process can be performed by dry etching or wet etching. Note that, when the inorganic insulating film 125f is formed using the same material as the sacrificial layers 158R, 158G, and 158B, the first etching process can be performed at once, which is preferable.

[0393] When dry etching is performed, it is preferable to use a chlorine-based gas. As the chlorine-based gas, Cl2, BCl3, SiCl4, CCl4, etc. can be used alone or in a mixture of two or more gases. In addition, oxygen gas, hydrogen gas, helium gas, argon gas, etc. can be appropriately added alone or in a mixture of two or more gases to the chlorine-based gas. By using dry etching, the thin film regions of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can be formed with good in-plane uniformity.

[0394] As the dry etching apparatus, a dry etching apparatus having a high density plasma source can be used. As the dry etching apparatus having a high density plasma source, for example, an inductively coupled plasma (ICP) etching apparatus can be used. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel plate electrodes can be used.

[0395] In addition, it is preferable to perform the first etching process by wet etching. By using the wet etching method, damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to the case of using the dry etching method. For example, the wet etching can be performed using an alkaline solution. For example, an alkaline solution, TMAH, can be used for wet etching of an aluminum oxide film. Also, an acid solution containing fluoride can be used. In this case, the wet etching can be performed by the paddle method. Note that, when the inorganic insulating film 125f is formed using the same material as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, the above-mentioned etching process can be performed at once, which is preferable.

[0396] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the etching process is stopped when the film thickness becomes thin. In this way, by leaving the corresponding sacrificial layers 158R, 158G, and 158B on the organic compound layers 103R, 103G, and 103B, it is possible to prevent the organic compound layers 103R, 103G, and 103B from being damaged in the subsequent process.

[0397] Next, the entire substrate is exposed to light, and it is preferable to irradiate the insulating layer 127a with visible light or ultraviolet light. The energy density of the exposure is 0 mJ / cm 2 Larger, 800mJ / cm 2 It is preferable to set the concentration to 0 mJ / cm or less. 2 Larger than 500mJ / cm 2 It is more preferable to set the following. By performing such exposure after development, the transparency of the insulating layer 127a can be improved in some cases. In addition, the substrate temperature required for a heat treatment for transforming the insulating layer 127a into a tapered shape in a later step can be reduced in some cases.

[0398] Here, the presence of a barrier insulating layer against oxygen (e.g., an aluminum oxide film, etc.) as the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B can reduce the diffusion of oxygen into the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B.

[0399] Next, a heat treatment (also referred to as post-baking) is performed. By performing the heat treatment, the insulating layer 127a can be transformed into the insulating layer 127 having a tapered shape on the side surface (FIG. 8C). The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer. The heat treatment can be performed at a substrate temperature of 50° C. to 200° C., preferably 60° C. to 150° C., more preferably 70° C. to 130° C. The heating atmosphere may be an air atmosphere or an inert gas atmosphere. The heating atmosphere may be an atmospheric pressure atmosphere or a reduced pressure atmosphere. This can improve the adhesion between the insulating layer 127 and the inorganic insulating layer 125 and also improve the corrosion resistance of the insulating layer 127.

[0400] In the first etching process, the sacrificial layers 158R, 158G, and 158B are not completely removed, and the sacrificial layers 158R, 158G, and 158B are left in a state where the film thickness is reduced, so that the organic compound layers 103R, 103G, and 103B can be prevented from being damaged and deteriorated in the heat treatment, thereby improving the reliability of the light-emitting device.

[0401] 9(A), an etching process is performed using the insulating layer 127 as a mask to remove parts of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B. As a result, openings are formed in the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, respectively, and the upper surfaces of the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, and the conductive layer 152C are exposed. Note that, hereinafter, this etching process may be referred to as a second etching process.

[0402] An end portion of the inorganic insulating layer 125 is covered with an insulating layer 127. Also, Fig. 9(A) shows an example in which a part 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.

[0403] The second etching process is performed by wet etching. By using the wet etching method, damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be reduced compared to the case of using the dry etching method. The wet etching can be performed using, for example, an alkaline solution or an acidic solution. It is preferable to use an aqueous solution so that the organic compound layer 103 does not dissolve.

[0404] 9(B), a common electrode 155 is formed on the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the conductive layer 152C, and the insulating layer 127. The common electrode 155 can be formed by a method such as a sputtering method or a vacuum deposition method. At this time, as shown in FIG. 3, the organic compound layer 103 may be formed as a laminated structure of the first EL layer 104 and the second EL layer 105, and the common electrode 155 may be formed thereon.

[0405] 9C, the protective layer 131 is formed on the common electrode 155. The protective layer 131 can be formed by a method such as a vacuum deposition method, a sputtering method, a CVD method, or an ALD method.

[0406] Then, the substrate 120 is attached over the protective layer 131 using the resin layer 122, so that a display device can be manufactured. As described above, in a manufacturing method of a display device according to one embodiment of the present invention, the insulating layer 156 is provided so as to have a region overlapping with a 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. This can increase the yield of the display device and suppress the occurrence of defects.

[0407] As described above, in the manufacturing method of the display device according to one embodiment of the present invention, the island-shaped organic compound layer 103R, the island-shaped organic compound layer 103G, and the island-shaped organic compound layer 103B are formed by forming a film on one surface and then processing it, instead of using a fine metal mask, so that the island-shaped layers can be formed with a uniform thickness. As a result, a display device with high resolution or a display device with a high aperture ratio can be realized. Even if the resolution or aperture ratio is high and the distance between the subpixels is extremely short, the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B can be prevented from contacting each other in adjacent subpixels. Therefore, leakage current can be prevented from occurring between the subpixels. As a result, crosstalk can be prevented, and a display device with extremely high contrast can be realized.

[0408] Furthermore, even in a display device having a tandem-type light-emitting device manufactured using a photolithography method, a light-emitting device that has excellent moisture resistance, water resistance, oxygen resistance, and chemical resistance, has a low driving voltage, and has good light-emitting efficiency can be provided.

[0409] (Embodiment 4) In this embodiment, a display device according to one embodiment of the present invention will be described.

[0410] The display device of the present embodiment can be a high-definition display device. Therefore, the display device of the present embodiment can be used for, for example, a display unit of a wristwatch-type or bracelet-type information terminal (wearable device), a VR device such as a head-mounted display (HMD), and a head-mounted wearable device such as a glasses-type AR device.

[0411] The display device of the present embodiment can be a high-resolution display device or a large-sized display device. Therefore, the display device of the present embodiment can be used in electronic devices having relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and sound reproducing devices.

[0412] [Display module] 10A shows a perspective view of a display module 280. The display module 280 has 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 either a display device 100B or a display device 100E, which will be described later.

[0413] The display module 280 has a substrate 291 and a substrate 292. The display module 280 has a display unit 281. The display unit 281 is a region that displays an image in the display module 280, and is a region where light from each pixel provided in a pixel unit 284 described later can be viewed.

[0414] 10B is a perspective view showing a schematic configuration of the substrate 291 side. 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 laminated on the substrate 291. A terminal portion 285 for connecting to an FPC 290 is provided in a portion of the substrate 291 that does not overlap with the pixel portion 284. The terminal portion 285 and the circuit portion 282 are electrically connected by a wiring portion 286 composed of a plurality of wirings.

[0415] The pixel section 284 has a plurality of pixels 284a arranged periodically. An enlarged view of one pixel 284a is shown on the right side of Fig. 10(B). The various configurations described in the previous embodiment can be applied to the pixel 284a. Fig. 10(B) shows an example in which the pixel 284a has the same configuration as the pixel 178 shown in Fig. 3.

[0416] The pixel circuit section 283 has a plurality of pixel circuits 283a that are periodically arranged.

[0417] One pixel circuit 283a is a circuit that controls the driving of a plurality of elements included in one pixel 284a.

[0418] The circuit portion 282 includes a circuit for driving each pixel circuit 283a of the pixel circuit portion 283. For example, it is preferable that the circuit portion 282 includes one or both of a gate line driver circuit and a source line driver circuit. In addition, the circuit portion 282 may include at least one of an arithmetic circuit, a memory circuit, a power supply circuit, and the like.

[0419] The FPC 290 functions as wiring for supplying a video signal, a power supply potential, or the like from the outside to the circuit portion 282. In addition, an IC may be mounted on the FPC 290.

[0420] Since the display module 280 can be configured such that one or both of the pixel circuit portion 283 and the circuit portion 282 are stacked below the pixel portion 284, the aperture ratio (effective display area ratio) of the display portion 281 can be made extremely high.

[0421] Such a display module 280 has extremely high resolution and can be suitably used in VR devices such as HMDs or glasses-type AR devices. For example, even in a configuration in which the display unit of the display module 280 is viewed through a lens, the display module 280 has an extremely high resolution display unit 281, so that pixels are not visible even when the display unit is enlarged with a lens, and a highly immersive display can be performed. In addition, the display module 280 is not limited to this and can be suitably used in electronic devices having a relatively small display unit.

[0422] [Display device 100A] A display device 100A shown in FIG. 11A 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.

[0423] The substrate 301 corresponds to the substrate 291 in FIGS. 10A and 10B. The transistor 310 is a transistor having a channel formation region in the substrate 301. For example, a semiconductor substrate such as a single crystal silicon substrate can be used as the substrate 301. The transistor 310 includes a part of the substrate 301, a conductive layer 311, a low-resistance region 312, an insulating layer 313, and an insulating layer 314. The conductive layer 311 functions as a gate electrode. The insulating layer 313 is located between the substrate 301 and the conductive layer 311 and functions as a gate insulating layer. The low-resistance region 312 is a region in which the substrate 301 is doped with impurities and functions as a source or drain. The insulating layer 314 is provided to cover a side surface of the conductive layer 311.

[0424] In addition, an element isolation layer 315 is provided between two adjacent transistors 310 so as to be embedded in the substrate 301 .

[0425] In addition, an insulating layer 261 is provided to cover the transistor 310 , and a capacitor 240 is provided on the insulating layer 261 .

[0426] Capacitor 240 has conductive layer 241, conductive layer 245, and insulating layer 243 located therebetween. Conductive layer 241 functions as one electrode of capacitor 240, conductive layer 245 functions as the other electrode of capacitor 240, and insulating layer 243 functions as a dielectric of capacitor 240.

[0427] The conductive layer 241 is provided over the insulating layer 261 and is embedded in the insulating layer 254. The conductive layer 241 is electrically connected to one of the source and the drain of the transistor 310 by a plug 271 embedded in the insulating layer 261. The insulating layer 243 is provided to cover the conductive layer 241. The conductive layer 245 is provided in a region overlapping with the conductive layer 241 with the insulating layer 243 interposed therebetween.

[0428] An insulating layer 255 is provided covering 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. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B are provided on the insulating layer 175. An insulator is provided in the region between adjacent light-emitting devices.

[0429] An insulating layer 156R is provided so as to have a region overlapping with a side surface of the conductive layer 151R, an insulating layer 156G is provided so as to have a region overlapping with a side surface of the conductive layer 151G, and an insulating layer 156B is provided so as to have a region overlapping with a side surface of the conductive layer 151B. A conductive layer 152R is provided so as to cover the conductive layer 151R and the insulating layer 156R, a conductive layer 152G is provided so as to cover the conductive layer 151G and the insulating layer 156G, and a conductive layer 152B is provided so as to cover the conductive layer 151B and the insulating layer 156B. A sacrificial layer 158R is located on the organic compound layer 103R, a sacrificial layer 158G is located on the organic compound layer 103G, and a sacrificial layer 158B is located on the organic compound layer 103B.

[0430] The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B are electrically connected to one of the source or the drain of the transistor 310 via an insulating layer 243, an insulating layer 255, an insulating layer 174, a plug 256 embedded in the insulating layer 175, a conductive layer 241 embedded in the insulating layer 254, and a plug 271 embedded in the insulating layer 261. Various conductive materials can be used for the plug.

[0431] Further, a protective layer 131 is provided on the light emitting devices 130R, 130G, and 130B. The substrate 120 is bonded onto the protective layer 131 by a resin layer 122. For details of the components from the light emitting devices 130 to the substrate 120, refer to the third embodiment. The substrate 120 corresponds to the substrate 292 in FIG. 10(A).

[0432] Fig. 11(B) is a modified example of the display device 100A shown in Fig. 11(A). The display device shown in Fig. 11(B) has a colored layer 132R, a colored layer 132G, and a colored layer 132B, and the light-emitting device 130 has an area overlapping one of the colored layer 132R, the colored layer 132G, and the colored layer 132B. In the display device shown in Fig. 11(B), the light-emitting device 130 can emit, for example, white light. Also, for example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light.

[0433] [Display device 100B] FIG. 12 shows a perspective view of the display device 100B.

[0434] The display device 100B has a configuration in which a substrate 352 and a substrate 351 are bonded together. In Fig. 12, the substrate 352 is indicated by a dashed line.

[0435] The display device 100B has a pixel unit 177, a connection unit 140, a circuit 356, wiring 355, etc. Fig. 12 shows an example in which an IC 354 and an FPC 353 are mounted on the display device 100B. Therefore, the configuration shown in Fig. 12 can also be called a display module having the display device 100B, an IC (integrated circuit), and an FPC. Here, a display device having a connector such as an FPC attached to a substrate, or a display device having an IC mounted on the substrate, is called a display module.

[0436] The connection section 140 is provided outside the pixel section 177. There may be one or more connection sections 140. The connection section 140 electrically connects the common electrode of the light emitting device and the conductive layer, and can supply a potential to the common electrode.

[0437] The circuit 356 can be, for example, a scanning line driver circuit.

[0438] The wiring 355 has a function of supplying signals and power to the pixel portion 177 and the circuit 356. The signals and power are input to the wiring 355 from the outside via the FPC 353 or from the IC 354.

[0439] 12 shows an example in which an IC 354 is provided on a substrate 351 by a chip on glass (COG) method or a chip on film (COF) method. For example, an IC having a scanning line driver circuit or a signal line driver circuit can be used as the IC 354. Note that the display device 100B and the display module may not include an IC. Also, the IC may be mounted on an FPC by a COF method, for example.

[0440] FIG. 13 shows an example of a cross section of the display device 100B, in which 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 are cut away.

[0441] [Display device 100C] The display device 100C shown in FIG. 13 has, between a substrate 351 and a substrate 352, a transistor 201, a transistor 205, a light-emitting device 130R that emits red light, a light-emitting device 130G that emits green light, and a light-emitting device 130B that emits blue light, etc.

[0442] For details of the light emitting devices 130R, 130G, and 130B, refer to the first to third embodiments.

[0443] Light-emitting device 130R has conductive layer 224R, conductive layer 151R on conductive layer 224R, and conductive layer 152R on conductive layer 151R. Light-emitting device 130G has conductive layer 224G, conductive layer 151G on conductive layer 224G, and conductive layer 152G on conductive layer 151G. Light-emitting device 130B has conductive layer 224B, conductive layer 151B on conductive layer 224B, and conductive layer 152B on conductive layer 151B.

[0444] The conductive layer 224R is connected to the conductive layer 222b of 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. An insulating layer 156R is provided to have a region in contact with a side surface of the conductive layer 151R, and a conductive layer 152R is provided to cover the conductive layer 151R and the insulating layer 156R.

[0445] Conductive layer 224G, conductive layer 151G, conductive layer 152G, and insulating layer 156G in light-emitting device 130G, and conductive layer 224B, conductive layer 151B, conductive layer 152B, and insulating layer 156B in light-emitting device 130B are similar to conductive layer 224R, conductive layer 151R, conductive layer 152R, and insulating layer 156R in light-emitting device 130R, and therefore detailed description thereof will be omitted.

[0446] Recesses are formed in the conductive layers 224R, 224G, and 224B so as to cover the openings provided in the insulating layer 214. The layer 128 is embedded in the recesses.

[0447] The layer 128 has a function of planarizing the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B. The conductive layer 151R, the conductive layer 151G, and the conductive layer 151B, which are electrically connected to the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, are provided on the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B, and the layer 128. Therefore, the regions overlapping with the recesses of the conductive layer 224R, the conductive layer 224G, and the conductive layer 224B can also be used as light-emitting regions, and the aperture ratio of the pixel can be increased.

[0448] The layer 128 may be an insulating layer or a conductive layer. Various inorganic insulating materials, organic insulating materials, and conductive materials can be appropriately used for the layer 128. In particular, the layer 128 is preferably formed using an insulating material, and more preferably formed using an organic insulating material. For example, the organic insulating material that can be used for the insulating layer 127 described above can be used for the layer 128.

[0449] 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 via an adhesive layer 142. The substrate 352 is provided with a light shielding layer 157. A solid sealing structure, a hollow sealing structure, or the like can be applied to seal the light emitting device 130. In FIG. 13, the space between the substrate 352 and the substrate 351 is filled with the adhesive layer 142, and a solid sealing structure is applied. Alternatively, the space may be filled with an inert gas (nitrogen, argon, or the like), and a hollow sealing structure may be applied. In this case, the adhesive layer 142 may be provided so as not to overlap with the light emitting device. The space may also be filled with a resin different from the adhesive layer 142 provided in a frame shape.

[0450] 13 shows an example in which the connection portion 140 has a conductive layer 224C obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive layer 151C obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive layer 152C obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. Also, FIG. 13 shows an example in which an insulating layer 156C is provided so as to have an area overlapping with a side surface of the conductive layer 151C.

[0451] The display device 100B is a top emission type. Light emitted by the light emitting device is emitted to the substrate 352 side. The substrate 352 is preferably made of a material that is highly transparent to visible light. When the light emitting element emits infrared or near infrared light, it is preferably made of a material that is highly transparent to the infrared light. The pixel electrode contains a material that reflects visible light, and the counter electrode (common electrode 155) contains a material that transmits visible light.

[0452] An insulating layer 211, an insulating layer 213, an insulating layer 215, and an insulating layer 214 are provided over a substrate 351 in this order. A part of the insulating layer 211 functions as a gate insulating layer for each transistor. A part of the insulating layer 213 functions as a gate insulating layer for each transistor. The insulating layer 215 is provided to cover the transistors. The insulating layer 214 is provided to cover the transistors and functions as a planarizing layer. Note that the number of gate insulating layers and the number of insulating layers covering the transistors are not limited, and each may be a single layer or two or more layers.

[0453] Each of the insulating layers 211, 213, and 215 is preferably an inorganic insulating film.

[0454] The insulating layer 214, which functions as a planarizing layer, is preferably an organic insulating layer.

[0455] The transistor 201 and the transistor 205 each have a conductive layer 221 functioning as a gate, an insulating layer 211 functioning as a gate insulating layer, a conductive layer 222a and a conductive layer 222b functioning as a source and a drain, a semiconductor layer 231, an insulating layer 213 functioning as a gate insulating layer, and a conductive layer 223 functioning as a gate.

[0456] A connection portion 204 is provided in a region of the substrate 351 where the substrate 352 does not overlap. In the connection portion 204, a source electrode or a drain electrode of the transistor 201 is electrically connected to the FPC 353 through a conductive layer 166 and a connection layer 242. The conductive layer 166 is an example of a laminated structure of a conductive film obtained by processing the same conductive film as the conductive layers 224R, 224G, and 224B, a conductive film obtained by processing the same conductive film as the conductive layers 151R, 151G, and 151B, and a conductive film obtained by processing the same conductive film as the conductive layers 152R, 152G, and 152B. On the upper surface of the connection portion 204, the conductive layer 166 is exposed. This allows the connection portion 204 and the FPC 353 to be electrically connected through the connection layer 242.

[0457] It is preferable to provide a light-shielding layer 157 on the surface of the substrate 352 facing the substrate 351. The light-shielding layer 157 can be provided between adjacent light-emitting devices, on the connection portion 140, on the circuit 356, etc. In addition, various optical members can be disposed on the outside of the substrate 352.

[0458] The materials usable for the substrate 120 can be used for the substrate 351 and the substrate 352, respectively.

[0459] The adhesive layer 142 may be made of a material that can be used for the resin layer 122 .

[0460] The connection layer 242 may be an anisotropic conductive film (ACF), an anisotropic conductive paste (ACP), or the like.

[0461] [Display device 100D] A display device 100D shown in FIG. 14 differs from the display device 100C shown in FIG. 13 mainly in that the display device 100D is a bottom-emission type display device.

[0462] Light emitted by the light emitting device is emitted to the side of the substrate 351. It is preferable that a material having high transparency to visible light is used for the substrate 351. On the other hand, the light transmissivity of a material used for the substrate 352 does not matter.

[0463] It is preferable to form a light-shielding layer between the substrate 351 and the transistor 201 and between the substrate 351 and the transistor 205. Fig. 14 shows an example in which a light-shielding layer 157 is provided over the substrate 351, an insulating layer 153 is provided over the light-shielding layer, and the transistors 201, 205, and the like are provided over the insulating layer 153.

[0464] Light emitting device 130R includes a conductive layer 112R, a conductive layer 126R on conductive layer 112R, and a conductive layer 129R on conductive layer 126R.

[0465] Light emitting device 130B has conductive layer 112B, conductive layer 126B on conductive layer 112B, and conductive layer 129B on conductive layer 126B.

[0466] The conductive layers 112R, 112B, 126R, 126B, 129R, and 129B are made of a material that is highly transparent to visible light. The common electrode 155 is preferably made of a material that reflects visible light.

[0467] Although the light emitting device 130G is not shown in FIG. 14, the light emitting device 130G is also provided.

[0468] In addition, although FIG. 14 and other figures show an example in which the upper surface of layer 128 has a flat portion, the shape of layer 128 is not particularly limited.

[0469] [Display device 100E] The display device 100E shown in FIG. 15 is a modification of the display device 100C shown in FIG. 13, and differs from the display device 100C mainly in that the display device 100E has colored layers 132R, 132G, and 132B.

[0470] In the display device 100E, the light emitting device 130 has an area overlapping one of the colored layer 132R, the colored layer 132G, and the colored layer 132B. The colored layer 132R, the colored layer 132G, and the colored layer 132B can be provided on the surface of the substrate 352 facing the substrate 351. An end of the colored layer 132R, an end of the colored layer 132G, and an end of the colored layer 132B can overlap the light blocking layer 157.

[0471] In the display device 100E, the light emitting device 130 can emit, for example, white light. For example, the colored layer 132R can transmit red light, the colored layer 132G can transmit green light, and the colored layer 132B can transmit blue light. The display device 100E may be configured such that the colored layers 132R, 132G, and 132B are provided between the protective layer 131 and the adhesive layer 142.

[0472] 13 and 15 and the like show an example in which the upper surface of the layer 128 has a flat portion, but the shape of the layer 128 is not particularly limited.

[0473] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate.

[0474] (Embodiment 5) In this embodiment, an electronic device according to one embodiment of the present invention will be described.

[0475] The electronic devices of this embodiment include the display device of one embodiment of the present invention in a display portion. The display device of one embodiment of the present invention has high display performance and can easily achieve high definition and high resolution. Therefore, the display device of one embodiment of the present invention can be used in the display portion of various electronic devices.

[0476] Examples of electronic devices include electronic devices with relatively large screens, such as television devices, desktop or notebook personal computers, computer monitors, digital signage, large game machines such as pachinko machines, as well as digital cameras, digital video cameras, digital photo frames, mobile phones, portable game machines, personal digital assistants, and audio playback devices.

[0477] In particular, the display device of one embodiment of the present invention can be suitably used in electronic devices having a relatively small display area because it can increase the resolution. Examples of such electronic devices include wristwatch-type and bracelet-type information terminals (wearable devices), and head-mounted wearable devices such as VR devices, glasses-type AR devices, and MR devices.

[0478] The electronic device of this embodiment may have a sensor (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays).

[0479] An example of a wearable device that can be worn on the head will be described with reference to FIGS. 16(A) to 16(D).

[0480] Electronic device 700A shown in FIG. 16(A) and electronic device 700B shown in FIG. 16(B) each have 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 members 753, a frame 757, and a pair of nose pads 758.

[0481] The display device of one embodiment of the present invention can be applied to the display panel 751. Thus, the electronic device can be highly reliable.

[0482] Each of the electronic device 700A and the electronic device 700B can project an image displayed on the display panel 751 onto a display area 756 of the optical member 753. Since the optical member 753 has translucency, a user can see the image displayed in the display area superimposed on a transmitted image visually recognized through the optical member 753.

[0483] The electronic device 700A and the electronic device 700B may be provided with a camera capable of capturing an image of the front as an imaging unit. In addition, the electronic device 700A and the electronic device 700B may each be provided with an acceleration sensor such as a gyro sensor, thereby detecting the orientation of the user's head and displaying an image corresponding to the orientation in the display area 756.

[0484] The communication unit has a wireless communication device and can supply, for example, a video signal through the wireless communication device. Note that instead of or in addition to the wireless communication device, a connector to which a cable through which a video signal and a power supply potential can be connected may be provided.

[0485] Furthermore, the electronic device 700A and the electronic device 700B are provided with a battery, which can be charged wirelessly and / or wired.

[0486] The housing 721 may be provided with a touch sensor module.

[0487] As the touch sensor module, various touch sensors can be applied. For example, various types of sensors can be adopted, such as a capacitance type, a resistive film type, an infrared type, an electromagnetic induction type, a surface acoustic wave type, or an optical type. In particular, it is preferable to apply a capacitance type or an optical type sensor to the touch sensor module.

[0488] Electronic device 800A shown in FIG. 16(C) and electronic device 800B shown in FIG. 16(D) each have a pair of display units 820, a housing 821, a communication unit 822, a pair of mounting units 823, a control unit 824, a pair of imaging units 825, and a pair of lenses 832.

[0489] The display device of one embodiment of the present invention can be applied to the display portion 820. Thus, the electronic device can be made highly reliable.

[0490] Display unit 820 is provided inside housing 821 at a position that can be viewed through lens 832. Also, by displaying different images on the pair of display units 820, it is possible to perform three-dimensional display using parallax.

[0491] It is preferable that electronic device 800A and electronic device 800B each have a mechanism capable of adjusting the left-right positions of lens 832 and display unit 820 so that they are optimally positioned according to the position of the user's eyes.

[0492] The mounting portion 823 allows the user to mount the electronic device 800A or the electronic device 800B on the head.

[0493] The imaging unit 825 has a function of acquiring external information. Data acquired by the imaging unit 825 can be output to the display unit 820. An image sensor can be used for the imaging unit 825. In addition, multiple cameras may be provided so as to be compatible with multiple angles of view, such as telephoto and wide angle.

[0494] The electronic device 800A may have a vibration mechanism that functions as a bone conduction earphone.

[0495] The electronic device 800A and the electronic device 800B may each have an input terminal. The input terminal can be connected to a cable for supplying a video signal from a video output device or the like and power for charging a battery provided in the electronic device.

[0496] The electronic device of one embodiment of the present invention may have a function of wireless communication with the earphone 750.

[0497] 16B includes an earphone unit 727. A part of a wiring connecting the earphone unit 727 and a control unit may be disposed inside the housing 721 or the attachment unit 723.

[0498] 16D includes an earphone unit 827. For example, the earphone unit 827 and the control unit 824 may be configured to be connected to each other by wire.

[0499] As described above, as electronic devices according to one embodiment of the present invention, both glasses-type devices (such as the electronic device 700A and the electronic device 700B) and goggles-type devices (such as the electronic device 800A and the electronic device 800B) are suitable.

[0500] An electronic device 6500 shown in FIG. 17A is a portable information terminal that can be used as a smartphone.

[0501] 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, and a light source 6508. The display portion 6502 has a touch panel function.

[0502] The display device of one embodiment of the present invention can be applied to the display portion 6502. Therefore, the electronic device can be highly reliable.

[0503] FIG. 17B is a schematic cross-sectional view including the end portion of the housing 6501 on the microphone 6506 side.

[0504] A light-transmitting protective member 6510 is provided on the display surface side of the housing 6501, and a display panel 6511, optical members 6512, a touch sensor panel 6513, a printed circuit board 6517, a battery 6518, etc. are arranged in the space surrounded by the housing 6501 and the protective member 6510.

[0505] A display panel 6511, an optical member 6512, and a touch sensor panel 6513 are fixed to the protective member 6510 by an adhesive layer (not shown).

[0506] In an area outside the display unit 6502, a part of the display panel 6511 is folded back, and the folded back part 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.

[0507] The light-emitting device of one embodiment of the present invention can be applied to the display panel 6511. Therefore, 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 mounted thereon while keeping the thickness of the electronic device small. In addition, by folding back a part of the display panel 6511 and arranging a connection portion with the FPC 6515 on the back side of the pixel portion, an electronic device with a narrow frame can be realized.

[0508] 17C shows an example of a television set. In a television set 7100, a display portion 7000 is incorporated in a housing 7171. Here, the housing 7171 is supported by a stand 7173.

[0509] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can be provided with high reliability.

[0510] A television set 7100 shown in FIG. 17C can be operated using an operation switch provided in a housing 7171 and a remote control 7151 provided separately.

[0511] 17D shows an example of a laptop personal computer 7200. The laptop personal computer 7200 includes a housing 7211, a keyboard 7212, a pointing device 7213, and an external connection port 7214. A display portion 7000 is incorporated in the housing 7211.

[0512] The display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can be provided with high reliability.

[0513] 17(E) and 17(F) show an example of digital signage.

[0514] 17E includes a housing 7301, a display portion 7000, and a speaker 7303. The digital signage 7300 may further include an LED lamp, an operation key (including a power switch or an operation switch), a connection terminal, various sensors, a microphone, and the like.

[0515] 17F shows a digital signage 7400 attached to a cylindrical pillar 7401. The digital signage 7400 has a display unit 7000 provided along the curved surface of the pillar 7401.

[0516] 17E and 17F, the display device of one embodiment of the present invention can be applied to the display portion 7000. Therefore, the electronic device can have high reliability.

[0517] The larger the display unit 7000, the more information can be provided at one time. Also, the larger the display unit 7000, the more easily it catches people's attention, which can increase the advertising effect of, for example, advertisements.

[0518] Furthermore, as shown in FIGS. 17(E) and 17(F), it is preferable that the digital signage 7300 or the digital signage 7400 be capable of linking with an information terminal 7311 or an information terminal 7411 such as a smartphone carried by a user via wireless communication.

[0519] The electronic devices shown in Figures 18(A) to 18(G) have a housing 9000, a display unit 9001, a speaker 9003, operation keys 9005 (including a power switch or an operation switch), a connection terminal 9006, a sensor 9007 (including a function of measuring force, displacement, position, speed, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor or infrared rays), a microphone 9008, etc.

[0520] 18(A) to 18(G) have various functions, such as a function of displaying various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function of displaying a calendar, date, time, etc., a function of controlling processing by various software (programs), a wireless communication function, a function of reading and processing a program or data recorded in a recording medium, etc.

[0521] The electronic devices shown in FIGS. 18A to 18G will be described in detail below.

[0522] FIG. 18A is a perspective view showing a mobile information terminal 9171. The mobile information terminal 9171 can be used as, for example, a smartphone. Note that the mobile information terminal 9171 may be provided with a speaker 9003, a connection terminal 9006, a sensor 9007, or the like. The mobile information terminal 9171 can display text and image information on a plurality of surfaces thereof. FIG. 18A shows an example in which three icons 9050 are displayed. Information 9051 shown in a dashed rectangle can also be displayed on another surface of the display unit 9001. Examples of the information 9051 include notification of incoming e-mail, SNS, phone call, etc., the title of the e-mail or SNS, the sender's name, date and time, time, remaining battery level, radio wave intensity, and the like. Alternatively, the icon 9050, etc. may be displayed at the position where the information 9051 is displayed.

[0523] 18(B) is a perspective view of a mobile information terminal 9172. The mobile 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, a user can check information 9053 displayed in a position that can be observed from above the mobile information terminal 9172 while the mobile information terminal 9172 is stored in a breast pocket of clothes.

[0524] 18C is a perspective view showing a tablet terminal 9173. The tablet terminal 9173 is capable of executing various applications such as mobile phone, e-mail, text browsing and creation, music playback, Internet communication, computer games, etc. The tablet terminal 9173 has a display unit 9001, a camera 9002, a microphone 9008, and a speaker 9003 on the front side of a housing 9000, operation keys 9005 as operation buttons on the left side of the housing 9000, and a connection terminal 9006 on the bottom.

[0525] FIG. 18D is a perspective view showing a wristwatch-type mobile information terminal 9200. The mobile information terminal 9200 can be used as, for example, a smart watch (registered trademark). The display surface of the display unit 9001 is curved, and display can be performed along the curved display surface. The mobile information terminal 9200 can also perform hands-free conversation by communicating with, for example, a headset capable of wireless communication. The mobile information terminal 9200 can also perform data transmission and charging with another information terminal through a connection terminal 9006. Note that charging may be performed by wireless power supply.

[0526] 18(E) to 18(G) are perspective views showing a foldable mobile information terminal 9201. FIG. 18(E) shows the mobile information terminal 9201 in an unfolded state, FIG. 18(G) shows the mobile information terminal 9201 in a folded state, and FIG. 18(F) shows a perspective view of a state in the middle of changing from one of FIG. 18(E) and FIG. 18(G) to the other. The mobile information terminal 9201 has excellent portability in a folded state, and has excellent viewability of a display due to a seamless wide display area in an unfolded state. A display portion 9001 of the mobile information terminal 9201 is supported by three housings 9000 connected by a hinge 9055. For example, the display portion 9001 can be bent with a curvature radius of 0.1 mm to 150 mm.

[0527] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in the case where a plurality of configuration examples are shown in one embodiment mode in this specification, the configuration examples can be combined as appropriate. EXAMPLES

[0528] In this example, a detailed fabrication method and characteristics of light-emitting devices 1-1 to 1-8, which are tandem light-emitting devices using an organic compound (second organic compound) having electron transport properties with different LUMO levels in the first layer of the intermediate layer, are described. The structural formulae of the main compounds used in this example are shown below.

[0529] [ka]

[0530] [ka]

[0531] (Method of manufacturing light-emitting device 1-1) First, on a glass substrate, 100 nm of silver (Ag) was laminated from the substrate side as a reflective electrode, and 85 nm of indium tin oxide containing silicon oxide (ITSO) was laminated as a transparent electrode by a sputtering method to form a first electrode 101 having a size of 2 mm x 2 mm. The transparent electrode functions as an anode, and is regarded as the first electrode 101 together with the reflective electrode.

[0532] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water and baked at 200° C. for 1 hour.

[0533] After that, about 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to 1 Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and the substrate was then allowed to cool for approximately 30 minutes.

[0534] Next, the substrate was fixed to a holder installed in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a material (OCHD-003) having a molecular weight of 672 and containing fluorine and having electron accepting properties were co-deposited on the first electrode 101 by a deposition method to a thickness of 10 nm in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003).

[0535] On the hole injection layer 111, PCBBiF was deposited to a thickness of 90 nm to form a first hole transport layer.

[0536] Subsequently, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP) represented by the above structural formula (iii), and [2-d3-methylphenyl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) represented by the above structural formula (iii), A first light-emitting layer was formed by co-evaporating 40 nm of 8mpTP-4mDBtPBfpm-βNCCP:Ir(5mppy-d3)2(mbfpypy-d3) and 8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)) in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)).

[0537] After that, 3,6-bis(diphenylamino)-9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9H-carbazole (abbreviation: DACT-II) represented by the above structural formula (v) was evaporated to a thickness of 10 nm to form a first electron transport layer.

[0538] After the formation of the first electron transport layer, 1,1'-pyridine-2,6-diyl-bis(1,3,4,6,7,8-hexahydro-2H-pyrimido[1,2-a]pyrimidine) (abbreviation: hpp2py) represented by the above structural formula (I) as the second organic compound and 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) represented by the above structural formula (vi) as the first organic compound were mixed in a weight ratio of 0.5:0.5 (=hpp2py:Pyrrd- After that, indium (In) was deposited to a thickness of 2 nm to form a layer that would become the first region, copper phthalocyanine (abbreviation: CuPc) represented by the above structural formula (vii) was deposited to a thickness of 2 nm to form a layer that would become the third region, and further PCBBiF and OCHD-003 were co-deposited to a weight ratio of 1:0.15 (=PCBBiF:OCHD-003) to a thickness of 10 nm to form a layer that would become the second region, thereby forming an intermediate layer.

[0539] On the intermediate layer, PCBBiF was evaporated to a thickness of 55 nm to form a second hole transport layer.

[0540] A second light-emitting layer was formed on the second hole-transporting layer by co-evaporation of 8mpTP-4mDBtPBfpm, βNCCP, and Ir(5mppy-d3)2(mbfpypy-d3) to a thickness of 40 nm in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)).

[0541] Thereafter, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (viii) was evaporated to a thickness of 20 nm, and further 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) represented by the above structural formula (ix) was evaporated to a thickness of 20 nm to form a second electron transport layer.

[0542] The sample on which the second electron transport layer was formed was exposed to the air for 1 hour. -4 The coated film was subjected to vacuum baking at 110° C. for 1 hour in a heating chamber of a vacuum deposition apparatus whose inside had been reduced in pressure to 100 Pa.

[0543] Thereafter, lithium fluoride (LiF) and ytterbium (Yb) were co-deposited to a volume ratio of 1:0.5 and a film thickness of 1.5 nm, and then silver (Ag) and magnesium (Mg) were co-deposited to a volume ratio of 1:0.1 and a film thickness of 15 nm to form the second electrode 102. In addition, a 70 nm film of 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II) represented by the above structural formula (x) was formed on the second electrode 102 as a cap layer to improve the light extraction efficiency.

[0544] Next, in a glove box with a nitrogen atmosphere, the light-emitting device was sealed with a glass substrate to prevent it from being exposed to the atmosphere (a UV-curable sealant was applied around the element, UV was irradiated only onto the sealant so as not to irradiate the light-emitting device, and heat treatment was performed at 80°C under atmospheric pressure for 1 hour), thereby forming light-emitting device 1-1.

[0545] (Method of fabricating light-emitting device 1-2) Light-emitting device 1-2 was prepared in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to mPPhen2P represented by the above structural formula (II).

[0546] (Method of manufacturing light-emitting device 1-3) Light-emitting device 1-3 was fabricated in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth) represented by the above structural formula (III).

[0547] (Method of fabricating light-emitting devices 1-4) Light-emitting device 1-4 was prepared in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN) represented by the above structural formula (IV).

[0548] (Method of fabricating light-emitting devices 1-5) Light-emitting device 1-5 was fabricated in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz) represented by the above structural formula (V).

[0549] (Method of manufacturing light-emitting devices 1-6) Light-emitting device 1-6 was prepared in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenanthrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn) represented by the above structural formula (VI).

[0550] (Method of manufacturing light-emitting device 1-7) Light-emitting device 1-7 was fabricated in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to 8mpTP-4mDBtPBfpm represented by the above structural formula (VII). Note that in light-emitting device 1-7, the first light-emitting layer and the second light-emitting layer contain the same organic compound as the second organic compound (8mpTP-4mDBtPBfpm) in the intermediate layer.

[0551] (Method of manufacturing light-emitting devices 1-8) Light-emitting device 1-8 was prepared in the same manner as light-emitting device 1-1, except that hpp2Py (second organic compound) in light-emitting device 1-1 was changed to 11-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr) represented by the above structural formula (VIII).

[0552] The device structures of light-emitting devices 1-1 to 1-8 and the LUMO levels of the second organic compounds are shown below. As described above, light-emitting devices 1-1 to 1-8 are light-emitting devices including a first layer containing a metal, a first organic compound containing a first π-electron-deficient heteroaromatic ring having an electron-donating group, and a second organic compound containing a second π-electron-deficient heteroaromatic ring.

[0553] The values ​​of the HOMO level and the LUMO level were determined by cyclic voltammetry (CV) measurement.

[0554] In the cyclic voltammetry (CV) measurement, the values ​​(E) of the HOMO level and the LUMO level were calculated based on the oxidation peak potential (Epa) and the reduction peak potential (Epc) obtained by changing the potential of the working electrode relative to the reference electrode. In the measurement, the HOMO level was obtained from the potential scan in the positive direction, and the LUMO level was obtained from the potential scan in the negative direction. The scan rate in the measurement was 0.1 V / s.

[0555] Specifically, the standard redox potential (Eo) (=(Epa+Epc) / 2) was calculated from the oxidation peak potential (Epa) and reduction peak potential (Epc) obtained from the cyclic voltammogram of the material, and then subtracted from the potential energy (Ex) relative to the vacuum level of the reference electrode to determine the HOMO level and LUMO level values ​​(E) (=Ex-Eo), respectively.

[0556] In the above, a reversible redox wave was obtained, but in the case of an irreversible redox wave, the HOMO level was calculated by subtracting a certain value (0.1 eV) from the oxidation peak potential (Epa) and assuming the reduction peak potential (Epc) to be the value obtained, and the standard redox potential (Eo) was calculated to one decimal place. In addition, in the calculation of the LUMO level, the reduction peak potential (Epc) was added to a certain value (0.1 eV) and assuming the value obtained to be the oxidation peak potential (Epa), and the standard redox potential (Eo) was calculated to one decimal place.

[0557] In addition, the glass transition temperatures (Tg) of the second organic compounds in the intermediate layers of the light-emitting devices 1-2 to 1-8 were measured by a differential scanning calorimeter (DSC) to find that mPPhen2P had a Tg of 135°C, αN-βNPAnth had a Tg of 128°C, ZADN had a Tg of 169°C, mSiTrz had a Tg of 108°C, mPn-mDMePyPTzn had a Tg of 121°C, 8mpTP-4mDBtPBfpm had a Tg of 120°C, and 11mDBtBPPnfpr had a Tg of 130°C, indicating that these compounds have high heat resistance.

[0558] [Table 5]

[0559] [Table 6]

[0560] The luminance-current density characteristics of the light-emitting devices 1-1 to 1-8 are shown in Fig. 22, the luminance-voltage characteristics in Fig. 23, the current efficiency-current density characteristics in Fig. 24, the current density-voltage characteristics in Fig. 25, and the electroluminescence spectra in Fig. 26. 2 The main characteristics in the vicinity are shown in Table 7. The luminance, CIE chromaticity, and electroluminescence spectrum were measured using a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) at room temperature.

[0561] [Table 7]

[0562] 22 to 26 and Table 6 show that all of the light-emitting devices 1-1 to 1-8 are tandem light-emitting devices having good current efficiency.

[0563] Moreover, from the current density-voltage characteristics of the light emitting devices 1-1 to 1-8 shown in FIG. 27, it was found that there was a difference in driving voltage among the light emitting devices 1-1 to 1-8.

[0564] Here, the current density of the light-emitting devices 1-1 to 1-8 is 50 mA / cm 2 A diagram showing the relationship between the voltage and the LUMO level of the second organic compound in this case is shown in Fig. 28. This diagram shows that a significant reduction in the driving voltage occurs when the LUMO level of the second organic compound is -2.75 eV or less, more significantly -2.80 eV or less, more significantly -2.85 eV or less, more significantly -2.90 eV or less, and furthermore -2.95 eV or less.

[0565] That is, in this Example, taking into consideration that the LUMO level of the first organic compound is −2.55 eV, it was found that in order to reduce the driving voltage of the light-emitting device, the LUMO level of the second organic compound is preferably 0.20 eV or more lower than the LUMO level of the first organic compound, more preferably 0.25 eV or more lower, even more preferably 0.30 eV or more lower, even more preferably 0.35 eV or more lower, and even more preferably 0.40 eV or more lower. EXAMPLES

[0566] In this example, a detailed fabrication method and characteristics of light-emitting devices 2-1 to 2-4, which are tandem light-emitting devices using an organic compound (second organic compound) having electron transport properties with different LUMO levels in the first layer of the intermediate layer, are described. The structural formulas of the main compounds used in this example are shown below.

[0567] [ka]

[0568] [ka]

[0569] (Method of manufacturing light-emitting device 2-1) First, on a glass substrate, 100 nm of an alloy of silver, palladium and copper (APC: Ag-Pd-Cu) was laminated as a reflective electrode from the substrate side, and 50 nm of indium tin oxide containing silicon oxide (ITSO) was laminated as a transparent electrode by sputtering to form a first electrode 101 having a size of 2 mm x 2 mm. The transparent electrode functions as an anode, and is regarded as the first electrode 101 together with the reflective electrode.

[0570] Next, as a pretreatment for forming a light-emitting device on the substrate, the substrate surface was washed with water and baked at 200° C. for 1 hour.

[0571] After that, about 1 × 10 -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to 1 Pa, and vacuum baking was carried out at 170° C. for 30 minutes in a heating chamber in the vacuum deposition apparatus, and the substrate was then allowed to cool for approximately 30 minutes.

[0572] Next, the substrate was fixed to a holder installed in a vacuum deposition apparatus so that the surface on which the first electrode 101 was formed was facing downward, and N-(biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) represented by the above structural formula (i) and a material (OCHD-003) having a molecular weight of 672 and containing fluorine and having electron accepting properties were co-deposited on the first electrode 101 by a deposition method to a thickness of 10 nm in a weight ratio of 1:0.03 (=PCBBiF:OCHD-003).

[0573] On the hole injection layer 111, PCBBiF was deposited to a thickness of 125 nm to form a first hole transport layer.

[0574] Subsequently, 8-(p-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) represented by the above structural formula (ii), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP) represented by the above structural formula (iii), and [2-d3-methylphenyl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm) represented by the above structural formula (iii), A first light-emitting layer was formed by co-evaporating 40 nm of 8mpTP-4mDBtPBfpm-βNCCP:Ir(5mppy-d3)2(mbfpypy-d3) and 8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)) in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)).

[0575] After that, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq) represented by the above structural formula (viii) was evaporated to a thickness of 10 nm to form a first electron transport layer.

[0576] After the formation of the first electron transport layer, 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) represented by the above structural formula (II) as the second organic compound, 4,7-di-1-pyrrolidinyl-1,10-phenanthroline (abbreviation: Pyrrd-Phen) represented by the above structural formula (vi) as the first organic compound, and indium (In) were mixed in a volume ratio of 0.5:0.5:0.02 (=mPPh mPPhen2P:Pyrrd-Phen:In) was co-evaporated to a thickness of 5 nm to form a layer that would become the first region, and then copper phthalocyanine (abbreviation: CuPc) represented by the above structural formula (vii) was co-evaporated to a thickness of 2 nm to form a layer that would become the third region, and then PCBBiF and OCHD-003 were co-evaporated to a thickness of 10 nm to form a layer that would become the second region, forming an intermediate layer. The glass transition temperature (Tg) of mPPhen2P was measured using a differential scanning calorimeter (DSC) and found to be 135°C, indicating that it has high heat resistance.

[0577] On the intermediate layer, PCBBiF was evaporated to a thickness of 55 nm to form a second hole transport layer.

[0578] A second light-emitting layer was formed on the second hole-transporting layer by co-evaporation of 8mpTP-4mDBtPBfpm, βNCCP, and Ir(5mppy-d3)2(mbfpypy-d3) to a thickness of 40 nm in a weight ratio of 0.5:0.5:0.1 (=8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3)).

[0579] Thereafter, 2mPCCzPDBq was evaporated to a thickness of 20 nm, and mPPhen2P was evaporated to a thickness of 20 nm to form a second electron transport layer.

[0580] Here, processing was performed using photolithography. After removing the sample with the second electron transport layer formed from the vacuum deposition device, an aluminum oxide film was formed to a thickness of 30 nm at 80°C by ALD (Atomic Layer Deposition) using trimethylaluminum (TMA) as a precursor ...

Claims

1. a first group of electrodes formed on the same insulating surface; a second electrode facing the first electrode group; a first layer group located between the first electrode group and the second electrode, the first electrode group includes a plurality of first electrodes each of which is independent for each of the plurality of light emitting devices; the first layer group includes a plurality of first layers each of which is independent for each of the plurality of light emitting devices; the second electrode being a continuous conductive layer shared by the plurality of light emitting devices; The light emitting device comprises: a first electrode which is one of the first electrode group, the second electrode, and a first layer which is one of the first layer group; the second electrode and the first layer overlap the first electrode; the first layer has a first light-emitting layer, a second light-emitting layer, and an intermediate layer located between the first light-emitting layer and the second light-emitting layer; the intermediate layer has a first region including a metal or 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 having a second π-electron deficient heteroaromatic ring, the LUMO level of the second organic compound is lower than the LUMO level of the first organic compound by 0.20 eV or more; A light-emitting device, wherein the distance between the first layer of the light-emitting device and a first layer of another light-emitting device adjacent to the light-emitting device is 0.5 μm or more and 5 μm or less.

2. In claim 1, When the LUMO level of the first organic compound is LUMO1 (eV), the LUMO level of the second organic compound (LUMO2 (eV)) is LUMO1-0.50≦LUMO2≦LUMO1-0.20 Meet the light-emitting devices.

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

4. In claim 1, A light-emitting device, wherein the first organic compound is an organic compound having an acid dissociation constant pKa of 8 or more.

5. In claim 1, A light-emitting device, wherein the first π-electron deficient heteroaromatic ring and the second π-electron deficient heteroaromatic ring are different.

6. In claim 1, A light-emitting device, 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.

7. In claim 1, The second organic compound has an acid dissociation constant pKa of less than 4.

8. In claim 1, the first light-emitting layer is located closer to the first electrode than the second light-emitting layer; the first light-emitting layer includes a third organic compound; The third organic compound has a third π-electron deficient heteroaromatic ring. A light-emitting device, wherein the third pi-electron deficient heteroaromatic ring is the same as the second pi-electron deficient heteroaromatic ring.

9. In claim 1, the first light-emitting layer is located closer to the first electrode than the second light-emitting layer; the first light-emitting layer includes a third organic compound; The light-emitting device, wherein the third organic compound is the same organic compound as the second organic compound.

10. In any one of claims 1 to 9, a first electron transport layer between the first light emitting layer and the intermediate layer; the first electron transport layer comprises a fourth organic compound; The fourth organic compound is a different organic compound than the third organic compound.

11. In any one of claims 1 to 9, The light-emitting device, wherein the metal is any one of Groups 3, 11, 12, and 13.

12. In any one of claims 1 to 9, The electron donating group is The light emitting device may include one or more of an alkyl group, an alkoxy group, an aryloxy group, an alkylamino group, an arylamino group, and a heterocyclic amino group.

13. In any one of claims 1 to 9, The minimum value of the electrostatic potential of the first organic compound is a threshold of the electron density distribution in atomic units of 0.0004 e / a ０ ３ In the case where ｈ 2. A light emitting device, comprising:

14. In the first region, the metal or the metal oxide, the first organic compound, and the second organic compound are mixed together. A light emitting device according to any one of the preceding claims.

15. In the first region, a layer containing the metal or the metal oxide and a layer in which the first organic compound and the second organic compound are mixed are stacked. A light emitting device according to any one of the preceding claims.

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