Light emitting device and display apparatus

Abstract

The present invention provides a light emitting device which has good characteristics. The present invention specifically provides a light emitting device wherein: a first hole transport layer has a multilayer structure that comprises a first layer and a second layer; the second layer is in contact with a first light emitting layer; the first layer has a first organic compound; the second layer has a second organic compound that has a LUMO level which is higher than that of an organic compound included in the first light emitting layer; the first light emitting layer has a first luminescent center material; a second light emitting layer has a second luminescent center material; the difference between the peak wavelength in the emission spectrum of the first luminescent center material and the peak wavelength in the emission spectrum of the second luminescent center material is 30 nm or less; and the first light emitting layer and the second light emitting layer include a light emitting layer that emits light in a color gamut which is different from that of a light emitting layer of at least one light emitting device among a plurality of other light emitting devices that are adjacent to the light emitting device.

Description

Light-emitting devices and displays

[0001] One embodiment of the present invention relates to a light-emitting device. Note that one embodiment of the present invention is not limited to the above technical field. The technical field of one embodiment of the invention disclosed in this specification and the like relates to an object, a method, or a manufacturing method. Alternatively, one embodiment of the present invention relates to a process, a machine, manufacture, or a composition of matter. Therefore, more specifically, examples of the technical field of one embodiment of the present invention disclosed in this specification include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting devices, power storage devices, memory devices, imaging devices, electronic devices, and driving methods thereof or manufacturing methods thereof.

[0002] In recent years, display devices have been expected to be used in a variety of applications. For example, large display devices are used in home television devices (also called televisions or television receivers), digital signage (electronic billboards), and public information displays (PIDs). Furthermore, development of mobile information terminals, such as smartphones and tablet terminals equipped with touch panels, is also underway.

[0003] There is also a demand for higher definition display devices. Devices requiring high-definition display devices, such as devices for virtual reality (VR), augmented reality (AR), substitutional reality (SR), and mixed reality (MR), are being actively developed.

[0004] As a display device, for example, a light-emitting device having a light-emitting device (also referred to as a light-emitting element) has been developed. A light-emitting device (also referred to as an EL device or an EL element) utilizing an electroluminescence (hereinafter referred to as EL) phenomenon has features 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 supply, and is therefore applied to a display device.

[0005] Tandem light-emitting devices in particular have attracted attention because they achieve high current efficiency, and Patent Documents 1 and 2 disclose tandem light-emitting devices using a separate coloring method.

[0006] JP 2005-317548 A JP 2023-161850 A

[0007] An object of one embodiment of the present invention is to provide a light-emitting device with good characteristics.An object of one embodiment of the present invention is to provide a light-emitting device with good emission efficiency.An object of one embodiment of the present invention is to provide a light-emitting device with good reliability.An object of one embodiment of the present invention is to provide a light-emitting device with low driving voltage.An object of one embodiment of the present invention is to provide a light-emitting device with good reliability and low driving voltage.

[0008] Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with good characteristics. Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with good emission efficiency. Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with good reliability. Another object of one embodiment of the present invention is to provide a display device with low driving voltage. Another object of one embodiment of the present invention is to provide a light-emitting device that can provide a display device with low driving voltage and good reliability.

[0009] Another object is to provide any one of an organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device that consumes low power, or to provide any one of an electronic device and a lighting device that is highly reliable, or to provide any one of a novel organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device.

[0010] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc.

[0011] One embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, an intermediate layer, a first hole transport layer, a second hole transport layer, a first light-emitting layer, a second light-emitting layer, and a first electron transport layer, in which the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first hole transport layer is located between the first electrode and the first light-emitting layer, the second hole transport layer is located between the intermediate layer and the second light-emitting layer, the first electron transport layer is located between the second light-emitting layer and the second electrode, and the first hole transport layer has a stacked structure including the first layer and the second layer, and the second layer is a first light-emitting layer and a second light-emitting layer, the first layer containing a first organic compound and the second layer containing a second organic compound having a LUMO level higher than that of the organic compound contained in the first light-emitting layer; the first light-emitting layer containing a first luminescent center substance and the second light-emitting layer containing a second luminescent center substance; a difference between a maximum peak wavelength in the emission spectrum of the first luminescent center substance and a maximum peak wavelength in the emission spectrum of the second luminescent center substance is 30 nm or less; and the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of a light-emitting layer contained in at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0012] One embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, an intermediate layer, a first hole transport layer, a second hole transport layer, a first light-emitting layer, a second light-emitting layer, and a first electron transport layer, wherein the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first hole transport layer is located between the first electrode and the first light-emitting layer, the second hole transport layer is located between the intermediate layer and the second light-emitting layer, the first electron transport layer is located between the second light-emitting layer and the second electrode, the second hole transport layer has a stacked structure including a third layer and a fourth layer, the fourth layer is in contact with the second light-emitting layer, and the third layer is a third organic the fourth layer comprises a fourth organic compound having a higher LUMO level than the organic compound in the second light-emitting layer; the first light-emitting layer comprises a first luminescent center substance; the second light-emitting layer comprises a second luminescent center substance; the first light-emitting layer comprises the first luminescent center substance; and the second light-emitting layer comprises a second luminescent center substance; a difference between a maximum peak wavelength in the emission spectrum of the first luminescent center substance and a maximum peak wavelength in the emission spectrum of the second luminescent center substance is 30 nm or less; and the first light-emitting layer and the second light-emitting layer comprise light-emitting layers that emit light in a color gamut different from that of a light-emitting layer in at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0013] One embodiment of the present invention is a light-emitting device having a first electrode, a second electrode, an intermediate layer, a first hole-transport layer, a second hole-transport layer, a first light-emitting layer, a second light-emitting layer, and a first electron-transport layer, in which the intermediate layer is located between the first electrode and the second electrode, the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first hole-transport layer is located between the first electrode and the first light-emitting layer, the second hole-transport layer is located between the intermediate layer and the second light-emitting layer, and the first electron-transport layer is located between the second light-emitting layer and the second electrode. The first hole-transport layer has a stacked structure including the first layer and the second layer, and the second layer is in contact with the first light-emitting layer. the first light-emitting layer has a second organic compound having a higher LUMO level than the organic compound in the first light-emitting layer; the second hole-transport layer has a stacked structure including a third layer and a fourth layer; the fourth layer is in contact with the second light-emitting layer; the third layer has the third organic compound; the fourth layer has a fourth organic compound having a higher LUMO level than the organic compound in the second light-emitting layer; a difference between a maximum peak wavelength in the emission spectrum of the first light-emitting center substance and a maximum peak wavelength in the emission spectrum of the second light-emitting center substance is 30 nm or less; and the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of an light-emitting layer in at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

[0014] In the light-emitting device, the first luminescent center substance and the second luminescent center substance are the same substance.

[0015] In the light-emitting device, the first organic compound includes an amine skeleton and a polycyclic aromatic ring.

[0016] In the light-emitting device, the third organic compound includes an amine skeleton and a polycyclic aromatic ring.

[0017] In the light-emitting device, the first organic compound and the third organic compound each contain an amine skeleton and a polycyclic aromatic ring, and the polycyclic aromatic ring contains a fluorene skeleton.

[0018] In the light-emitting device, the first organic compound and the third organic compound are the same organic compound.

[0019] In the light-emitting device, the second organic compound includes an amine skeleton and a polycyclic heteroaromatic ring.

[0020] In the light-emitting device, the fourth organic compound includes an amine skeleton and a polycyclic heteroaromatic ring.

[0021] In the light-emitting device, the second organic compound and the fourth organic compound each contain an amine skeleton and a polycyclic heteroaromatic ring, and the polycyclic heteroaromatic ring contains a furan skeleton.

[0022] In the light-emitting device, the second organic compound and the fourth organic compound are the same organic compound.

[0023] In the light-emitting device, the first electron transport layer has a layer having a fifth organic compound having a triazine skeleton, and the intermediate layer has a mixed layer of a sixth organic compound having a phenanthroline skeleton and lithium or a lithium compound.

[0024] In the light-emitting device, the first electron transport layer has a mixed layer of a seventh organic compound having a triazine skeleton and lithium or a lithium compound, and the mixed layer is located between the layer having the fifth organic compound and the second electrode.

[0025] In the above light-emitting device, the light-emitting device has a second electron transport layer located between the first light-emitting layer and the intermediate layer, and the second electron transport layer is a light-emitting device having a seventh organic compound including any one of a pyrimidine skeleton, an imidazole skeleton, and an anthracene skeleton.

[0026] One embodiment of the present invention is a display device including a light-emitting device A and a light-emitting device B emitting light of a different color from that of the light-emitting device A. The light-emitting device A includes a first electrode A, a second electrode A, an intermediate layer A, a first hole-transporting layer A, a second hole-transporting layer A, a first light-emitting layer A, a second light-emitting layer A, and an electron-transporting layer A. The intermediate layer A is located between the first electrode A and the second electrode A. The first light-emitting layer A is located between the first electrode A and the intermediate layer A. The second light-emitting layer A is located between the intermediate layer A and the second electrode A. The first hole-transporting layer A is located between the first electrode A and the intermediate layer A. the second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A; the second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A; the electron transport layer A is located between the second light-emitting layer A and the second electrode A; the first hole transport layer A has a laminated structure including a first layer A and a second layer A; the second layer A is in contact with the first light-emitting layer A; the first layer A contains a first organic compound A; the second layer A contains a second organic compound A having a higher LUMO level than the organic compound contained in the first light-emitting layer A; the second hole transport layer A has a laminated structure including a third layer A and a fourth layer A; the fourth layer A is in contact with the second light-emitting layer A; A includes a third organic compound A, a fourth layer A includes a fourth organic compound A having a higher LUMO level than the organic compound included in the second light-emitting layer A, the first light-emitting layer A includes a first luminescence center substance A, and the second light-emitting layer A includes a second luminescence center substance A, and a difference between a maximum peak wavelength in the emission spectrum of the first luminescence center substance A and a maximum peak wavelength in the emission spectrum of the second luminescence center substance A is 30 nm or less, and the light-emitting device B includes a first electrode B, a second electrode B, an intermediate layer B, a first hole transport layer B, a second hole transport layer B, the first light-emitting layer B, the second light-emitting layer B, and an electron transport layer B, wherein the intermediate layer B is located between a first electrode B and a second electrode B, a first light-emitting layer B is located between the first electrode B and the intermediate layer B, a second light-emitting layer B is located between the intermediate layer B and the second electrode B, a first hole transport layer B is located between the first electrode B and the first light-emitting layer B, a second hole transport layer B is located between the intermediate layer B and the second light-emitting layer B, and an electron transport layer B is located between the second light-emitting layer B and the second electrode B, the first hole transport layer B comprises a first organic compound B, and the second hole transport layer B comprises a third organic compound B;The first light-emitting layer B has a first light-emitting center substance B, the second light-emitting layer B has a second light-emitting center substance B, the difference between the maximum peak wavelength in the emission spectrum of the first light-emitting center substance B and the maximum peak wavelength in the emission spectrum of the second light-emitting center substance B is 30 nm or less, and the first light-emitting layer A and the second light-emitting layer A emit light in a color gamut different from that of the first light-emitting layer B and the second light-emitting layer B.

[0027] Another embodiment of the present invention is a light-emitting device including the light-emitting device having any of the above structures and a transistor or a substrate.

[0028] Another embodiment of the present invention is an electronic device including a light-emitting device having any of the above structures and a detection unit, an input unit, or a communication unit.

[0029] In this specification, the term "light-emitting device" includes an image display device using a light-emitting device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or a TCP (Tape Carrier Package), is attached to a light-emitting device on a substrate, a module in which a printed wiring board is provided at the end of the TCP, or a module in which an IC (integrated circuit) is directly mounted on a light-emitting device using a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may have a light-emitting device.

[0030] According to one embodiment of the present invention, a light-emitting device with favorable characteristics can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable emission efficiency can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable reliability can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with low driving voltage can be provided. Alternatively, according to one embodiment of the present invention, a light-emitting device with favorable reliability and low driving voltage can be provided.

[0031] Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with good characteristics. Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with good emission efficiency. Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with good reliability. Alternatively, one embodiment of the present invention can provide a display device with low driving voltage. Alternatively, one embodiment of the present invention can provide a light-emitting device that can provide a display device with low driving voltage and good reliability.

[0032] Alternatively, any one of an organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device with low power consumption can be provided. Alternatively, any one of an electronic device and a lighting device with high reliability can be provided. Alternatively, any one of a novel organic semiconductor device, a light-emitting device, a light-receiving device, a display device, an electronic device, and a lighting device can be provided.

[0033] 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.

[0034] FIGS. 1A and 1B are diagrams illustrating a light-emitting device. FIG. 2 is a diagram illustrating a light-emitting device. FIGS. 3A and 3B are diagrams illustrating a light-emitting device. FIG. 4 is a diagram illustrating a light-emitting device. FIGS. 5A and 5B are diagrams illustrating a display device according to one embodiment of the present invention. FIGS. 6A and 6B are top views and cross-sectional views of a light-emitting device. FIGS. 7A to 7E are cross-sectional views illustrating an example of a manufacturing method of a display device. FIGS. 8A and 8B are cross-sectional views illustrating an example of a manufacturing method of a display device. FIGS. 9A to 9D are cross-sectional views illustrating an example of a manufacturing method of a display device. FIGS. 10A to 10C are cross-sectional views illustrating an example of a manufacturing method of a display device. FIGS. 11A to 11C are cross-sectional views illustrating an example of a manufacturing method of a display device. FIGS. 12A to 12C are cross-sectional views illustrating an example of a manufacturing method of a display device. FIGS. 13A to 13G are top views illustrating an example of a pixel configuration. FIGS. 14A to 14I are top views illustrating an example of a pixel configuration. FIGS. 15A and 15B are perspective views illustrating an example of a display module configuration. FIGS. 16A and 16B are cross-sectional views showing an example of the configuration of a display device. FIG. 17 is a perspective view showing an example of the configuration of a display device. FIG. 18 is a cross-sectional view showing an example of the configuration of a display device. FIG. 19 is a cross-sectional view showing an example of the configuration of a display device. FIG. 20A is a cross-sectional view showing an example of the configuration of a display device, and FIGS. 20B and 20C are top views showing an example of the configuration of a display device. FIG. 21 is a cross-sectional view showing an example of the configuration of a display device. FIG. 22A is a cross-sectional view showing an example of the configuration of a display device, and FIGS. 22B and 22C are top views showing an example of the configuration of a display device. FIGS. 23A to 23D are views showing an example of an electronic device. FIGS. 24A to 24F are views showing an example of an electronic device. FIGS. 25A to 25G are views showing an example of an electronic device. FIG. 26 is a diagram explaining the structure of a sample. FIG. 27 is a diagram explaining the structure of a sample. FIG. 28 is a diagram showing the luminance-current density characteristics of a sample. FIG. 29 is a diagram showing the luminance-voltage characteristics of a sample. FIG. 30 is a diagram showing the current efficiency-current density characteristics of a sample. FIG. 31 is a diagram showing the current density-voltage characteristics of a sample. Figure 32 shows the electroluminescence spectrum of the sample. Figure 33 shows the blue index-current density characteristics of the sample. Figure 34 shows the luminance-current density characteristics of the sample. Figure 35 shows the luminance-voltage characteristics of the sample.FIG. 36 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 37 is a graph showing the current density-voltage characteristics of the sample. FIG. 38 is a graph showing the electroluminescence spectrum of the sample. FIG. 39 is a graph showing the luminance-current density characteristics of the sample. FIG. 40 is a graph showing the luminance-voltage characteristics of the sample. FIG. 41 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 42 is a graph showing the current density-voltage characteristics of the sample. FIG. 43 is a graph showing the electroluminescence spectrum of the sample. FIG. 44 is a graph showing the results of reliability measurements of the sample. FIG. 45 is a diagram explaining the structure of the sample. FIG. 46 is a diagram explaining the structure of the sample. FIG. 47 is a diagram showing the luminance-current density characteristics of the sample. FIG. 48 is a diagram showing the luminance-voltage characteristics of the sample. FIG. 49 is a diagram showing the current efficiency-current density characteristics of the sample. FIG. 50 is a diagram showing the current density-voltage characteristics of the sample. FIG. 51 is a diagram showing the electroluminescence spectrum of the sample. FIG. 52 is a diagram showing the blue index-current density characteristics of the sample. FIG. 53 is a diagram showing the luminance-current density characteristics of the sample. FIG. 54 is a graph showing the luminance-voltage characteristics of the sample. FIG. 55 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 56 is a graph showing the current density-voltage characteristics of the sample. FIG. 57 is a graph showing the electroluminescence spectrum of the sample. FIG. 58 is a graph showing the luminance-current density characteristics of the sample. FIG. 59 is a graph showing the luminance-voltage characteristics of the sample. FIG. 60 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 61 is a graph showing the current density-voltage characteristics of the sample. FIG. 62 is a graph showing the electroluminescence spectrum of the sample. FIG. 63 is a graph showing the luminance-current density characteristics of the sample. FIG. 64 is a graph showing the luminance-voltage characteristics of the sample. FIG. 65 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 66 is a graph showing the current density-voltage characteristics of the sample. FIG. 67 is a graph showing the electroluminescence spectrum of the sample. FIG. 68 is a graph showing the blue index-current density characteristics of the sample. FIG. 69 is a graph showing the luminance-current density characteristics of the sample. FIG. 70 is a graph showing the luminance-voltage characteristics of the sample. Fig. 71 shows the current efficiency-current density characteristics of the sample. Fig. 72 shows the current density-voltage characteristics of the sample. Fig. 73 shows the electroluminescence spectrum of the sample. Fig. 74 shows the luminance-current density characteristics of the sample.FIG. 75 is a graph showing the luminance-voltage characteristics of the sample. FIG. 76 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 77 is a graph showing the current density-voltage characteristics of the sample. FIG. 78 is a graph showing the electroluminescence spectrum of the sample. FIG. 79 is a graph showing the luminance-current density characteristics of the sample. FIG. 80 is a graph showing the luminance-voltage characteristics of the sample. FIG. 81 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 82 is a graph showing the current density-voltage characteristics of the sample. FIG. 83 is a graph showing the electroluminescence spectrum of the sample. FIG. 84 is a graph showing the blue index-current density characteristics of the sample. FIG. 85 is a graph showing the luminance-current density characteristics of the sample. FIG. 86 is a graph showing the luminance-voltage characteristics of the sample. FIG. 87 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 88 is a graph showing the current density-voltage characteristics of the sample. FIG. 89 is a graph showing the electroluminescence spectrum of the sample. FIG. 90 is a graph showing the luminance-current density characteristics of the sample. FIG. 91 is a graph showing the luminance-voltage characteristics of the sample. FIG. 92 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 93 is a graph showing the current density-voltage characteristics of the sample. FIG. 94 is a graph showing the electroluminescence spectrum of the sample. FIG. 95 is a graph showing the luminance-current density characteristics of the sample. FIG. 96 is a graph showing the luminance-voltage characteristics of the sample. FIG. 97 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 98 is a graph showing the current density-voltage characteristics of the sample. FIG. 99 is a graph showing the electroluminescence spectrum of the sample. FIG. 100 is a graph showing the blue index-current density characteristics of the sample. FIG. 101 is a graph showing the luminance-current density characteristics of the sample. FIG. 102 is a graph showing the luminance-voltage characteristics of the sample. FIG. 103 is a graph showing the current efficiency-current density characteristics of the sample. FIG. 104 is a graph showing the current density-voltage characteristics of the sample. FIG. 105 is a graph showing the electroluminescence spectrum of the sample. FIG. 106 is a graph showing the luminance-current density characteristics of the sample. FIG. 107 is a graph showing the luminance-voltage characteristics of the sample. FIG. 108 is a graph showing the current efficiency-current density characteristics of the sample. Fig. 109 shows the current density-voltage characteristics of the sample, and Fig. 110 shows the electroluminescence spectrum of the sample.

[0035] 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 readily understood by those skilled in the art that various changes can be made in form and detail 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.

[0036] In the configuration of the invention described below, the same parts or parts having similar functions are denoted by the same reference numerals in different drawings, and repeated explanations thereof will be omitted. In addition, when referring to similar functions, the same hatch pattern may be used and no particular reference numeral may be assigned.

[0037] Furthermore, for ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings.

[0038] The terms "film" and "layer" can be interchangeable depending on the circumstances. For example, the term "conductive layer" can be changed to the term "conductive film." Or, for example, the term "insulating film" can be changed to the term "insulating layer."

[0039] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution 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.

[0040] In this specification and the like, holes or electrons may be referred to as "carriers." Specifically, a hole injection layer or an electron injection layer may be referred to as a "carrier injection layer," a hole transport layer or an electron transport layer may be referred to as a "carrier transport layer," and a hole block layer or an electron block layer may be referred to as a "carrier block layer." Note that the above-mentioned carrier injection layer, carrier transport layer, and carrier block layer may not be clearly distinguishable. Furthermore, one layer may have two or three functions among the carrier injection layer, carrier transport layer, and carrier block layer. Furthermore, the terms "injection layer," "transport layer," and "block layer" may be simply referred to as "layer." Similarly, other layers such as "light-emitting layer" and "intermediate layer" may also be referred to as "layer."

[0041] In this specification and the like, a light-emitting device (also referred to as a light-emitting element) has an EL layer between a pair of electrodes. The EL layer has at least a light-emitting layer. In this specification and the like, a light-receiving device (also referred to as a light-receiving element) has at least an active layer that functions as a photoelectric conversion layer between a pair of electrodes. In this specification and the like, one of the pair of electrodes may be referred to as a pixel electrode, and the other as a common electrode.

[0042] In this specification, the term "tapered shape" refers to a shape in which at least a portion of the side surface of the structure is inclined relative to the substrate surface. For example, it is preferable to have a region in which the angle (also called the taper angle) between the inclined side surface and the substrate surface is less than 90°. The side surface of the structure and the substrate surface do not necessarily need to be completely flat, but may be substantially planar with a slight curvature or a slight unevenness.

[0043] In this specification, the term "light-emitting device" includes an image display device using an organic EL device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or a TCP (Tape Carrier Package), is attached to an organic EL device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (integrated circuit) is directly mounted on an organic EL device using a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may have a light-emitting device.

[0044] In one embodiment of the present invention, a hole-transport layer included in an light-emitting unit of a tandem light-emitting device has a stacked structure of a first hole-transport layer and a second hole-transport layer in contact with the light-emitting layer. The second hole-transport layer preferably uses an organic compound whose lowest unoccupied molecular orbital (LUMO) level is higher than that of a host material of the light-emitting layer.

[0045] A tandem light-emitting device has a structure in which multiple light-emitting units are stacked between a pair of electrodes with an intermediate layer (charge-generating layer) sandwiched between them. Each of the multiple light-emitting units has a light-emitting layer, and light can be emitted from any of the light-emitting layers by passing a current through them. A tandem light-emitting device having such a configuration has significantly higher current efficiency than a non-tandem light-emitting device, and is therefore suitable for use in display devices that require high brightness or high reliability.

[0046] Tandem light-emitting devices have multiple light-emitting layers, making it easy to produce white light. Therefore, full-color display devices using tandem light-emitting devices often use a white color filter system. Color conversion systems using a blue-emitting light-emitting layer and a color conversion layer, typically a quantum dot, have also been put to practical use.

[0047] On the other hand, some display devices using tandem light-emitting devices that employ a color-coded method for full color have also been put to practical use. Light-emitting devices using the color-coded method have no or little energy loss in the color filters or color conversion layers, making them more efficient than the two methods mentioned above.

[0048] Furthermore, it is preferable that the light-emitting layer of the tandem light-emitting device is separated from the light-emitting layer of at least one of the other adjacent light-emitting devices, or that the light-emitting layer of the tandem light-emitting device has a light-emitting layer different from the light-emitting layer of at least one of the other adjacent light-emitting devices, or that the color of light emitted by the tandem light-emitting device is different from the color of light emitted by at least one of the other adjacent light-emitting devices, or that the light-emitting center substance of the light-emitting layer of the tandem light-emitting device has a different structure from the light-emitting center substance of the light-emitting layer of at least one of the other adjacent light-emitting devices.

[0049] The light-emitting device of the present invention having the above structure can be a light-emitting device with high current efficiency, low energy loss, and favorable characteristics. A display device according to one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and high luminance and thus favorable visibility.

[0050] Next, a light-emitting device of one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1A illustrates a light-emitting device 130 of one embodiment of the present invention. The light-emitting device of one embodiment of the present invention is a tandem light-emitting device including a first electrode 101 including an anode and a second electrode 102 including a cathode, and an organic compound layer 103 (also referred to as an EL layer) including a first light-emitting unit 501 including a first light-emitting layer 113_1 and a first hole-transport layer 112_1, a second light-emitting unit 502 including a second light-emitting layer 113_2 and a second hole-transport layer 112_2, and an intermediate layer 160.

[0051] Although the present embodiment describes an example of a light-emitting device having one intermediate layer 160 and two light-emitting units, the light-emitting device may have n (n is an integer of 1 or more) intermediate layers and n+1 light-emitting units. For example, the light-emitting device 130 shown in FIG. 1B is an example of a tandem light-emitting device in which n is 2, and includes a first light-emitting unit 501, a first intermediate layer 160_1, a second light-emitting unit 502, a second intermediate layer 160_2, and a third light-emitting unit 503.

[0052] The color gamut of the light emitted by the light-emitting layer in each light-emitting unit may be the same or different.

[0053] In the light-emitting device 130, the first hole-transport layer 112_1 has a stacked structure of a hole-transport layer 112_1a and a hole-transport layer 112_1b, and the hole-transport layer 112_1b is in contact with the first light-emitting layer 113_1. In addition, in the light-emitting device 130, the second hole-transport layer 112_2 has a stacked structure of a hole-transport layer 112_2a and a hole-transport layer 112_2b, and the hole-transport layer 112_2b is in contact with the second light-emitting layer 113_2.

[0054] Here, for the hole-transport layer 112_1 a and the hole-transport layer 112_2 a, an organic compound having an amine skeleton and a polycyclic aromatic ring is preferably used, and an organic compound having an amine skeleton and a fluorene skeleton is more preferably used because the organic compound having an amine skeleton and a fluorene skeleton has good reliability, high hole-transport properties, and reduced power consumption.

[0055] The hole-transport layer 112_1b and the hole-transport layer 112_2b are formed using a material that has high hole-transport properties, low electron-transport properties, and a high LUMO level. In particular, the hole-transport layer 112_1b and the hole-transport layer 112_2b are formed using a material whose LUMO level is higher than the LUMO level of the material constituting the light-emitting layer (at least the host material, preferably the material constituting the light-emitting layer, the material with the largest composition ratio among the materials constituting the light-emitting layer, or the material with the highest LUMO level among the materials constituting the light-emitting layer), preferably a material that is 0.30 eV or higher. For this purpose, the hole-transport layer 112_1b and the hole-transport layer 112_2b are preferably formed using an organic compound having an amine skeleton and a polycyclic heteroaromatic ring, and more preferably an organic compound having an amine skeleton and a furan skeleton or a dibenzofuran skeleton.

[0056] The provision of the hole-transport layer 112_1b can prevent electrons from passing through from the first light-emitting layer 113_1 to the first electrode 101. Similarly, the provision of the hole-transport layer 112_2b can prevent electrons from passing through from the second light-emitting layer 113_2 to the intermediate layer 160, so that a highly efficient and long-life display device can be manufactured.

[0057] That is, by forming the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2 with a stacked structure in which organic compounds with different properties are combined, the degree of freedom in designing a display device can be improved.

[0058] Specifically, organic compounds having an aromatic amine skeleton are preferably used as organic compounds that can be used for the hole-transport layers 112_1a, 112_2a, 112_1b, and 112_2b. Examples of aromatic rings contained in organic compounds having an aromatic amine skeleton include monocyclic aromatic rings and polycyclic aromatic rings. These aromatic rings may have an alkyl group as a substituent.

[0059] Examples of monocyclic aromatic rings include aromatic hydrocarbon rings such as benzene rings and heteroaromatic rings such as pyrrole rings and furan rings. Having an aromatic ring as a substituent improves heat resistance, specifically, improves the glass transition temperature (Tg) of the organic compound. Having an aromatic ring as a substituent also improves the transportability of carriers such as holes or electrons. Having a plurality of these monocyclic aromatic rings can further improve Tg, and for example, a biphenyl structure or a terphenyl structure is preferred. The compound may have a paraphenylene structure, a metaphenylene structure, or an orthophenylene structure. Having at least one of a metaphenylene structure or an orthophenylene structure can improve the solubility of the compound, facilitate production, and also reduce the refractive index. In addition, when a compound has three or more benzene rings, such as a terphenyl structure, having an aromatic ring containing at least two of a paraphenylene structure, a metaphenylene structure, and an orthophenylene structure is preferred because it can adjust the solubility and refractive index as well as the carrier transportability.

[0060] In addition, when a benzene ring is used as a linking group, it is usually called a phenylene group, but to avoid complicating the explanation, it may also be called a phenyl group when used as a linking group. Similarly, when other aromatic rings are used as linking rings, they may be called an aryl group instead of an arylene group, or a heteroaryl group instead of a heteroarylene group. In addition, the term benzene ring may be referred to as a benzene structure or a benzene skeleton, and such terminology applies to other substituents (such as aromatic rings).

[0061] Examples of polycyclic aromatic rings include aromatic hydrocarbon rings such as naphthalene rings, phenanthrene rings, chrysene rings, triphenylene rings, fluorene rings, and spirobifluorene rings, as well as heteroaromatic rings such as carbazole rings, dibenzofuran rings, dibenzothiophene rings, and xanthene rings. Compounds having polycyclic aromatic rings as substituents are preferred because they can improve heat resistance compared to compounds having monocyclic aromatic rings. It is also preferred to have multiple of these polycyclic aromatic rings. When multiple polycyclic aromatic rings are present, they may be the same or different. When they are the same ring, examples include a structure having multiple aromatic hydrocarbon rings, a structure having multiple heteroaromatic rings, and a structure having one or more aromatic hydrocarbon rings and one or more heteroaromatic rings. When multiple polycyclic aromatic rings are present, they may be the same or different aromatic rings. When they are the same aromatic ring, reduction in raw material costs and simplification of the synthesis process can be expected. In addition, when different aromatic rings are used, the transportability of carriers such as holes or electrons or Tg can be adjusted depending on the type of aromatic ring used. Examples of polycyclic aromatic rings include a structure having a carbazole ring and a dibenzofuran ring, a structure having two, three, or four or more carbazole rings, and a structure having two, three, or four or more fluorene rings.

[0062] Furthermore, in the case of a compound having, as a substituent, a ring in which an aromatic ring (such as the above-mentioned monocyclic aromatic ring or a monocyclic aromatic ring) is further condensed with the polycyclic aromatic ring, the heat resistance can be further improved. Examples of the ring in which an aromatic ring is further condensed with the polycyclic aromatic ring include a benzofluorene ring, a benzonaphthofuran ring, a benzoxanthene ring, and a benzonaphthothiophene ring.

[0063] The monocyclic aromatic ring and the polycyclic aromatic ring can be used as the substituent. Examples include a structure in which a monocyclic aromatic ring is used as a linking group between the nitrogen in the amine skeleton and the polycyclic aromatic ring. Examples include a structure in which a phenylene group is used between the nitrogen and the fluorene ring, a structure in which a phenylene group is used between the nitrogen and the carbazole ring, or a structure in which a phenylene group is used between the nitrogen and the dibenzofluorene ring. A structure in which multiple polycyclic aromatic rings are bonded to one phenylene group used as a linking group is also effective. The multiple polycyclic aromatic rings may be the same or different aromatic rings. For example, a compound in which both a carbazole ring and a dibenzofluorene ring are bonded to one phenylene group can improve Tg and obtain the functions of both the carbazole ring and the dibenzofluorene ring.

[0064] Examples of alkyl groups include methyl, ethyl, propyl, tert-butyl, cyclohexyl, and adamantyl groups. A layer using a compound having an alkyl group as a substituent can lower the refractive index. Therefore, total reflection at the interface between the layer and other layers can be reduced, improving light extraction efficiency. Furthermore, using a compound having these substituents in the hole transport layer can also reduce the refractive index. In particular, using a compound having an aromatic amine skeleton and an alkyl group in the hole transport layer can synergistically enhance the effect of improving light extraction efficiency. Furthermore, the alkyl group can enhance the effect by having multiple carbon atoms, preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more. Furthermore, it is preferable that multiple alkyl groups are bonded to one aromatic ring, as this can further reduce the refractive index. In this case, the multiple alkyl groups may be the same or different. For example, two or three tert-butyl groups may be bonded to one benzene ring. Furthermore, in a case where multiple aromatic rings are present, bonding alkyl groups to two or more aromatic rings can reduce the refractive index. Furthermore, the refractive index can be adjusted by including an alkyl group in some of the aromatic rings. For example, when the compound has three aromatic rings, two of the aromatic rings may have alkyl groups, and the remaining aromatic ring may not have an alkyl group.

[0065] As specific examples of organic compounds containing an aromatic amine skeleton, the structures of the organic compounds are shown as the following structural formulas (300) to (330). In particular, BBASF (4) shown in structural formula (300), oBBASF shown in structural formula (301), BBAFLP (4) shown in structural formula (302), oFBiSF (2) shown in structural formula (303), FBiSF (4) shown in structural formula (304), oFBiSF shown in structural formula (305), FBimFLP shown in structural formula (306), and FBimMemFL shown in structural formula (307). P, SF(4)FAF represented by structural formula (308), FrBBiFLP represented by structural formula (309), tBu-oFBiSF(2) represented by structural formula (310), FBiFLPB represented by structural formula (311), DBfBBFLP(2) represented by structural formula (312), FLP2oBP represented by structural formula (313), PCAFLP(2)-02 represented by structural formula (314), tBu2FoFBi shown in structural formula (316), oFrTPPnox shown in structural formula (317), mPDBfBNBN shown in structural formula (317), BBAaBnf shown in structural formula (318) (7), DBfBB1TP shown in structural formula (319), BOx3Am shown in structural formula (320), BBA2BP shown in structural formula (321), PCBBi1BP shown in structural formula (322), structural formula (323) YGBBiBP-02 represented by the structural formula (324), YGBBiBP represented by the structural formula (324), PCBBiTP represented by the structural formula (325), YGBBiPDBf represented by the structural formula (326), BPPCA represented by the structural formula (327), PCBBiF represented by the structural formula (328), DBf-YGBBiBP represented by the structural formula (329), and YGTPDBfB represented by the structural formula (330) are preferred.

[0066]

[0067]

[0068]

[0069]

[0070] For example, for the hole-transport layer 112_1a and the hole-transport layer 112_2a, among the organic compounds represented by structural formulas (300) to (330), it is preferable to use an organic compound having an amine skeleton and a polycyclic aromatic ring, and it is preferable to use an organic compound having an amine skeleton and a fluorene skeleton.

[0071] For the hole-transport layer 112_1b and the hole-transport layer 112_2b, among the organic compounds represented by Structural Formulas (300) to (330), an organic compound having an amine skeleton and a polycyclic heteroaromatic ring is preferably used, and an organic compound having an amine skeleton and a furan skeleton or a dibenzofuran skeleton is preferably used. Furthermore, an organic compound having a LUMO level higher than that of a material constituting the light-emitting layer (at least a host material, preferably a material constituting the light-emitting layer) may be appropriately selected and used.

[0072] Furthermore, the first light-emitting unit 501 and the second light-emitting unit 502 may include other functional layers in addition to the above-mentioned light-emitting layer, electron transport layer, and other layers. FIG. 1A illustrates a structure in which the first light-emitting unit 501 includes the hole-injection layer 111 and the first electron-transport layer 114_1 in addition to the first light-emitting layer 113_1 and the first hole-transport layer 112_1 (the hole-transport layer 112_1a and the hole-transport layer 112_1b), and the second light-emitting unit 502 includes the second electron-transport layer 114_2 and the electron-injection layer 115 in addition to the second light-emitting layer 113_2 and the second hole-transport layer 112_2 (the hole-transport layer 112_1a and the hole-transport layer 112_1b). However, the structure of the organic compound layer 103 in one embodiment of the present invention is not limited thereto, and any of the layers may not be provided, or other layers may be provided.

[0073] 1A, the first electron-transporting layer 114_1 and the second electron-transporting layer 114_2 are illustrated as single layers, but the first electron-transporting layer 114_1 and the second electron-transporting layer 114_2 may have a single layer structure or a stacked structure. In addition, the first electron-transporting layer 114_1 and the second electron-transporting layer 114_2 do not necessarily have the same structure.

[0074] For example, the first electron-transporting layer 114_1 may be a single layer, and the second electron-transporting layer 114_2 may be a stacked layer. Specifically, the electron-transporting layer included in the cathode-side light-emitting unit (e.g., the second electron-transporting layer 114_2 in FIG. 1A ) may have a stacked layer structure, and the electron-transporting layer included in the other light-emitting unit (e.g., the first electron-transporting layer 114_1 in FIG. 1A ) may have a single layer structure.

[0075] The electron transport layer included in the cathode-side light-emitting unit may preferably contain at least one layer of an organic compound containing a triazine skeleton. Alternatively, it may have a laminated structure using organic compounds containing different triazine skeletons. In particular, it is preferable that the cathode-side layer of the laminated layers contains an organic compound containing a triazine skeleton and an alkali metal such as Li. This structure can improve electron injection properties.

[0076] The electron transport layer included in the light-emitting unit located closer to the anode than the light-emitting unit located on the cathode side (hereinafter also referred to as the anode-side light-emitting unit) may use the same organic compound as that used in the electron transport layer included in the cathode-side light-emitting unit, or may use a different organic compound. For example, the electron transport layer may use an organic compound containing a triazine skeleton that is different from the organic compound containing a triazine skeleton used in the electron transport layer included in the cathode-side light-emitting unit.

[0077] In order to reduce power consumption, it is preferable that the electron transport layer included in the light-emitting unit on the anode side also contains an organic compound containing a triazine skeleton. In particular, using the same organic compound as that used in the electron transport layer included in the light-emitting unit on the cathode side is preferable because it prevents the manufacturing equipment from becoming complicated and is advantageous in terms of raw material procurement costs.

[0078] Furthermore, the electron transport layer included in the light-emitting unit on the anode side contains an organic compound that does not contain a triazine skeleton, which makes it easier to control the carrier transport property and enables the provision of a light-emitting device with better characteristics. As the organic compound that does not contain a triazine skeleton, an organic compound that contains a heteroaromatic ring having a pyridine skeleton or an organic compound that contains a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton is preferred. Organic compounds that contain a triazine skeleton, a pyrimidine skeleton, an imidazole skeleton, or an anthracene skeleton can be used.

[0079] The electron transport layer included in the light-emitting unit on the anode side may have either a laminated structure or a single layer structure, but the laminated structure provides high current efficiency, lower power consumption, and a light-emitting device with good characteristics. A single structure is advantageous in terms of manufacturing costs because fewer film-forming chambers are required.

[0080] The organic compound having a triazine skeleton that can be used in the electron transport layer included in the light-emitting unit on the anode side and the electron transport layer included in the light-emitting unit on the cathode side has 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 It is preferable that the material has an electron transporting property with an electron mobility of 1 / Vs or more. Note that other materials can be used as long as they have a higher electron transporting property than holes.

[0081] The organic compound containing a triazine skeleton is preferably a compound containing a triazine skeleton and an aromatic ring. The aromatic ring may be a monocyclic aromatic ring, a polycyclic aromatic ring, an aromatic ring having an alkyl group as a substituent, an aromatic ring having a fluoro group as a substituent, or an aromatic ring having a cyano group as a substituent. The triazine skeleton may have a substituent other than the aromatic ring, and the aromatic ring may have a substituent other than the fluoro group, cyano group, or alkyl group. The triazine skeleton is also called a triazine ring, and the skeleton of other skeletons can also be referred to as a ring.

[0082] Examples of the monocyclic aromatic ring include aromatic hydrocarbon rings such as a benzene ring, and heteroaromatic rings such as a pyrrole ring, a pyridine ring, a pyrimidine ring, a triazine ring, etc. Having an aromatic ring as a substituent improves heat resistance, specifically, has the effect of improving the glass transition temperature (Tg) and the effect of improving electron transport properties.

[0083] Examples of polycyclic aromatic rings include aromatic hydrocarbon rings such as naphthalene rings, phenanthrene rings, chrysene rings, triphenylene rings, fluorene rings, and spirobifluorene rings, as well as heteroaromatic rings such as carbazole rings, dibenzofuran rings, dibenzothiophene rings, xanthene rings, indolocarbazole rings, and indenocarbazole rings. Compounds having polycyclic aromatic rings as substituents are preferred because they can improve heat resistance compared to compounds having benzene rings. Furthermore, compounds having a ring in which an aromatic ring (such as a benzene ring, a naphthalene ring, or a pyridine ring) is fused to these polycyclic aromatic rings as a substituent can further improve heat resistance. Examples of rings in which an aromatic ring is fused to a polycyclic aromatic ring include a benzofluorene ring, a benzonaphthofuran ring, a benzoxanthene ring, and a benzonaphthothiophene ring. By providing a layer containing a highly heat-resistant compound near the cathode, damage to the element due to heat can be suppressed when high-temperature treatment such as a patterning step is performed after the layer or the cathode is formed.

[0084] Examples of alkyl groups include methyl, ethyl, propyl, tert-butyl, cyclohexyl, and adamantyl groups. A layer using a compound having an alkyl group as a substituent can lower the refractive index. Therefore, total reflection at the interface between the layer and other layers can be reduced, improving light extraction efficiency. Furthermore, using a compound having these substituents in the hole transport layer can also lower the refractive index. In particular, using a compound having a triazine skeleton and an alkyl group in the electron transport layer and a compound having an aromatic amine skeleton and an alkyl group in the hole transport layer can synergistically enhance the light extraction efficiency improvement effect. Furthermore, the alkyl group can be made to have multiple carbon atoms, preferably 3 or more, more preferably 4 or more, and even more preferably 5 or more, to enhance the effect. A layer using a compound having a fluoro group as a substituent is also preferred because it can lower the refractive index. In particular, having multiple fluoro groups can enhance the refractive index improvement effect. It is also effective to use a compound having a fluoro group in both the electron transport layer and the hole transport layer.

[0085] In addition, a compound having a cyano group as a substituent is preferable because it can improve the electron transport property.

[0086] It is also preferable to combine a polycyclic aromatic ring, an alkyl group, a fluoro group, or a cyano group as a substituent. For example, when a polycyclic aromatic ring and a cyano group are used as a substituent, both heat resistance and electron transport properties can be improved. Furthermore, when a polycyclic aromatic ring and an alkyl group are used as a substituent, both heat resistance and light extraction efficiency can be improved. In this way, a combination of substituents can be used depending on the desired function.

[0087] Furthermore, the heat resistance can be further improved by including a plurality of polycyclic aromatic rings as substituents. In this case, it is preferable that the aromatic hydrocarbon ring and the heteroaromatic ring are included.

[0088] Specific examples of organic compounds containing a triazine skeleton include 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), and 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn). azine (abbreviation: mBnfBPTzn-02), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5- triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6 -dimethyl-3-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-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-triazine (abbreviation: βNP-SFx(4)Tzn), 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPI cz(II)Tzn), 3-{3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]phenyl}-9-phenyl-9H-carbazole (abbreviation: mPCPDBfTzn), 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazine-4,3''-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothienyl]-2-phenyl-9H-carbazole (abbreviation: PCzDBtTzn), 2,4-diphenyl-6-[3′-(spiro[7H-benzo[c]fluorene-7,9′-[9H]xanthene]-2-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviation: mSbfxBPTzn), 3′-[4-phenyl-6-(spiro[9H-fluorene-9,9′-[9H]xanthene]-2′-yl)-1,3,Organic compounds containing a heteroaromatic ring having a triazine skeleton, such as [5-triazin-2-yl]biphenyl-4-carbonitrile (mpCNBP-SFxTzn) and 2,2′-[1,2-naphthalenediyldi(4,1-phenylene)]bis(4,6-diphenyl-1,3,5-triazine) (abbreviation: TznP2N), can be used. In particular, TznP2N represented by the following structural formula (500), mSbfxBPTzn represented by the following structural formula (501), mpCNBP-SFxTzn represented by the following structural formula (502), CNBPNPTzn represented by the following structural formula (503), βNP-SFx(4)Tzn represented by the following structural formula (504), mmtBuBP-mDMePyPTzn represented by the following structural formula (505), and mBnfBPTzn represented by the following structural formula (506) are preferred.

[0089]

[0090] Furthermore, materials that can be used for the electron transport layer included in the light-emitting unit on the anode side include those having an electron mobility of 1×10 at a square root of an electric field strength [V / cm] of 600 or less. −７ cm ２ / Vs or more, preferably 1×10 −６ cm ２ A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can be used as long as they have a higher electron transport property than holes. Note that the organic compound is preferably an organic compound having a π-electron-deficient heteroaromatic ring. As the organic compound having a π-electron-deficient heteroaromatic ring, for example, 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 are preferred, and triazine is particularly preferred. Note that organic compounds obtained by appropriately deuterating the above-mentioned organic compounds can also be used.

[0091] As an organic compound having electron transport properties that can be used in the electron transport layer included in the light-emitting unit on the anode side, the electron transport materials described below can be used. In particular, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred because of their high 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 can reduce driving voltage.

[0092] In addition, in one embodiment of the present invention, in the tandem light-emitting device, the intermediate layer 160 preferably contains an organic compound having a phenanthroline skeleton.

[0093] The organic compound containing the phenanthroline skeleton has 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 It is preferable that the material has an electron transporting property with an electron mobility of 1 / Vs or more. Note that other materials can be used as long as they have a higher electron transporting property than holes.

[0094] The organic compound containing a phenanthroline skeleton is preferably a compound containing a phenanthroline skeleton and an aromatic ring, and the aromatic ring may be a monocyclic aromatic ring or a polycyclic aromatic ring.

[0095] The monocyclic aromatic ring may be a benzene ring, a pyrrole ring, a pyridine ring, a pyrimidine ring, etc. The polycyclic aromatic ring preferably includes an aromatic hydrocarbon ring such as a naphthalene ring, a phenanthrene ring, a chrysene ring, a triphenylene ring, or a fluorene ring, or a heteroaromatic ring such as a phenanthroline ring or a pyrrole ring. In particular, the inclusion of a plurality of these polycyclic aromatic rings is preferred because it can improve heat resistance or electron transport properties.

[0096] Examples of organic compounds containing a phenanthroline skeleton include 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), and 2-phenyl-9-(2-triphenylenyl)phenyl.

[0033] An organic compound containing a heteroaromatic ring having a phenanthroline skeleton, such as 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: Ph-TpPhen), 2-[4-(9-phenanthrenyl)-1-naphthalenyl]-1,10-phenanthroline (abbreviation: PnNPhen), or 2-[4-(2-triphenylenyl)phenyl]-1,10-phenanthroline (abbreviation: pTpPPhen), can be used. However, PnNPhen shown in the following structural formula (200) or mPPhen2P shown in structural formula (201) is particularly preferred.

[0097]

[0098] In the light-emitting device of one embodiment of the present invention, the intermediate layer may have any structure as long as it contains an organic compound having a phenanthroline skeleton and can inject electrons into the light-emitting unit on the anode side and holes into the light-emitting unit on the cathode side, both of which are in contact with the intermediate layer, by applying a voltage between the first electrode and the second electrode. However, as shown in FIG. 1A , the intermediate layer 160 preferably has a stacked structure including a first layer 161 containing an organic compound and a second layer 162 located closer to the cathode than the first layer 161.

[0099] The first layer 161 preferably contains a metal or a metal compound in addition to an organic compound. The metal or the metal in the metal compound is preferably 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 lanthanoid such as Y, Eu, or Yb, a Group 11 element such as Cu, Ag, or Au, a Group 12 element such as Zn, or an earth metal (Group 13 element) such as Al or In.

[0100] The first layer 161 may have a stacked structure of a layer containing an organic compound and a layer containing a metal or a metal compound located closer to the cathode than the layer containing the organic compound. Alternatively, the first layer 161 may be a mixed layer of an organic compound and a metal or a metal compound. Note that the first layer 161 is preferably a mixed layer because it requires fewer deposition chambers and reduces manufacturing costs, and also contributes to improving the stability of the light-emitting device.

[0101] When an organic compound and a metal or metal compound are mixed, the distribution of the organic compound and the distribution of the metal or metal compound show roughly the same tendency when the first layer 161 is analyzed in the film thickness direction. That is, when the distribution of the organic compound is constant, the distribution of the metal or metal compound is also roughly constant. In the case of a layered structure of an organic compound and a metal or metal compound, the metal or metal compound may be detected in regions other than the layer made of the metal or metal compound due to diffusion from the layer made of the metal or metal compound, but since the distribution shows a different distribution from the distribution of the organic compound, the analysis results can be distinguished as diffusion or mixing.

[0102] Furthermore, when the first layer 161 is analyzed in the film thickness direction, if there is a region in which a metal or metal compound is detected that is 10 nm or more in thickness, preferably 15 nm or more, and more preferably 20 nm or more in thickness, the first layer 161 can be considered to have a mixed layer in which an organic compound and a metal or metal compound are mixed.

[0103] Among these, the metal in the metal or metal compound is preferably a substance that exhibits donor properties to an organic compound containing a phenanthroline skeleton. Examples of substances that exhibit donor properties to an organic compound containing a phenanthroline skeleton include metals of Group 1 and Group 2, and lithium or lithium compounds are particularly preferred. Specifically, Li, lithium fluoride (LiF), lithium oxide (Li ２Preferred examples of the light-emitting device of the present invention include 8-quinolinolato-lithium (abbreviation: Liq), 8-quinolinolato-lithium (abbreviation: Liq), and the like. When the first layer 161 is a layer containing an organic compound having a phenanthroline skeleton and a substance that exhibits a donor property to the organic compound having the phenanthroline skeleton, electrons are generated by charge separation, and when a voltage is applied between the first electrode and the second electrode, the electrons are injected into the light-emitting unit on the anode side via the organic compound having the phenanthroline skeleton. As a result, the light-emitting device of one embodiment of the present invention can be a light-emitting device with low driving voltage.

[0104] In addition to the organic compounds described above, the organic compound containing a phenanthroline skeleton is preferably an organic compound containing a phenanthroline skeleton having an electron-donating substituent. The phenanthroline skeleton is a skeleton that easily interacts with metals, etc., and when such an organic compound containing a phenanthroline skeleton further has an electron-donating group, the electron density of the phenanthroline skeleton increases, making it easier to interact with metals or metal compounds. In particular, when a metal belonging to Groups 3, 11, 12, or 13 is used as the metal or the metal compound, a tandem light-emitting device can be provided that suppresses an increase in driving voltage and has excellent characteristics.

[0105] Specific examples of the electron-donating group 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 phenanthroline ring is not limited to these. Any group that can increase the electron density of the phenanthroline ring by introducing it into the phenanthroline ring can be used as the electron-donating group. In addition, the electron-donating group may be introduced into the phenanthroline ring via an arylene group such as a phenylene group, and the arylene group is preferably a p-phenylene group.

[0106] Specific examples of organic compounds containing a phenanthroline skeleton having an electron-donating substituent are shown in structural formulas (203) to (213).

[0107]

[0108] Note that a configuration in which the first layer 161 contains an element of Group 1 or Group 2, particularly lithium or a lithium compound, and an organic compound containing a phenanthroline skeleton with an electron-donating substituent is preferable because it can provide a tandem light-emitting device with lower driving voltage and better reliability. Furthermore, a configuration in which the first layer 161 contains an element of Group 1 or Group 2, particularly lithium or a lithium compound, and an organic compound containing a phenanthroline skeleton with an electron-donating substituent is preferable because it can suppress an increase in driving voltage when the organic compound of the light-emitting device is processed by photolithography.

[0109] In an intermediate layer having the configuration described above, organic compounds containing a phenanthroline skeleton, particularly organic compounds containing a 1,10-phenanthroline skeleton among phenanthroline skeletons, are preferred because they have two nitrogen atoms that can coordinate to a metal and therefore are more likely to interact with a metal or metal compound.

[0110] When an electron-donating group is introduced into the 1,10-phenanthroline skeleton, the electron-donating group is preferably substituted at positions 4 and 7 of the 1,10-phenanthroline skeleton. By introducing the electron-donating group into positions 4 and 7 of the 1,10-phenanthroline skeleton, the electron density of the nitrogen atoms at positions 1 and 10 can be increased, making it easier for the compound to interact with a metal or metal compound.

[0111] The first layer 161 may further contain an organic compound different from the organic compound containing a phenanthroline skeleton. The organic compound is preferably an organic compound having electron transport properties. In particular, the organic compound preferably has two or more heteroaromatic rings bonded or condensed to each other, and the two or more heteroaromatic rings preferably have a total of three or more heteroatoms. By including such an organic compound in the first layer, improvements in heat resistance and electron transport properties can be achieved.

[0112] The second layer 162 preferably contains an organic compound having hole-transporting properties. The second layer 162 preferably further contains a substance exhibiting acceptor properties, and the substance exhibiting acceptor properties is preferably an organic compound that exhibits acceptor properties to an organic compound having hole-transporting properties. As the substance exhibiting acceptor properties, an organic compound having at least one of a halogen group and a cyano group is particularly preferred, and an organic compound having at least one of a fluorine group and a cyano group is more preferred. It is more preferred that the organic compound contains four or more halogen groups (fluorine) and cyano groups in total.

[0113] When the second layer 162 is a layer containing an organic compound having a hole-transporting property and a substance that exhibits acceptor properties for the organic compound having a hole-transporting property, holes are generated by charge separation, and when a voltage is applied between the first electrode and the second electrode, the holes are injected into the light-emitting unit on the cathode side through the organic compound having a hole-transporting property. Thus, the light-emitting device of one embodiment of the present invention can be a light-emitting device with low driving voltage.

[0114] The intermediate layer may have a third layer 163 between the first layer 161 and the second layer 162 .

[0115] The third layer contains a substance having an electron transporting property and has functions such as reducing the driving voltage by smoothing the transfer of electrons between the first layer 161 and the second layer 162, and improving reliability by reducing the interaction between the first layer 161 and the second layer 162.

[0116] The thickness of the third layer 163 is preferably 1 nm to 10 nm, more preferably 2 nm to 5 nm, in order to suppress an increase in driving voltage.

[0117] The light-emitting device of the present invention having the above-described structure can be a light-emitting device with high current efficiency, low energy loss, and favorable characteristics. In addition, a display device according to one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and high luminance and thus favorable visibility.

[0118] Here, among the multiple layers (e.g., hole transport layer, intermediate layer, light-emitting layer, electron transport layer, cap layer, etc.) that the light-emitting device has, the compound used in one layer and the compound used in another layer may be different compounds and may contain the same aromatic ring (monocyclic aromatic ring or polycyclic aromatic ring) as a substituent. By containing the same aromatic ring even if the compounds are different, it is expected that the cost of raw materials when producing the compound will be reduced or the number of synthesis steps will be shortened.

[0119] Aromatic rings that can be used in such different compounds include a naphthalene ring, a fluorene ring, a benzofluorene ring, a triphenylene ring, a benzonaphthofuran ring, a xanthene ring, a benzoxanthene ring, and a spirofluorenexanthene ring. :SFx), spirobenzofluorenexanthene ring (also referred to as Sbfx), carbazole ring, benzocarbazole ring, dibenzofuran ring, dibenzothiophene ring, benzonaphthothiophene ring, and other fused rings (also referred to as fused structures). These structures are shown below. When the aromatic ring shown below is substituted, any one of the carbons or nitrogen atoms is a bond.

[0120]

[0121] Furthermore, these fused rings can adjust the carrier transportability or Tg depending on the position at which they are bonded to other groups (also referred to as the bonding position), and therefore can be used in various layers. For example, it is preferable to use a naphthalene ring having a bonding position at the 1-position as the electron transport layer material and a naphthalene ring having a bonding position at the 2-position as the hole transport layer material. It is also preferable to use a naphthalene ring having a bonding position at the 2-position as the host material for the light-emitting layer and a naphthalene ring having a bonding position at the 1-position as the hole transport layer material. When a naphthalene ring is used as a linking group, it is preferable to use a naphthalene ring having bonding positions at the 1- and 2-positions as the electron transport layer material and a naphthalene ring having bonding positions at the 1- and 6-positions as the host material for the light-emitting layer. In this way, it is preferable to use fused rings having different bonding positions in a compound used in one layer and a compound used in another layer.

[0122] Furthermore, when the same fused ring is used in multiple layers, it is preferable to use different substituents, such as using a fused ring (e.g., a naphthalene ring) to which a cyano group is bonded as the material for the electron transport layer and using a fused ring (e.g., a naphthalene ring) to which an alkyl group is bonded as the material for the hole transport layer, thereby making it possible to provide materials suited to the properties required for each layer.

[0123] In addition, aromatic rings that are structurally isomeric may also be used, rather than being limited to the same aromatic ring. Using aromatic rings that are structurally isomeric may also allow production using the same raw materials, as in the case described above, which is expected to reduce raw material costs or shorten the synthesis steps. For example, structural isomers of a benzonaphthofuran ring include three condensed structures, namely, a benzo[b]naphtho[2,1-d]furan ring (also referred to as an aBnf skeleton), a benzo[b]naphtho[2,3-d]furan ring (also referred to as a Bnf(II) skeleton), and a benzo[b]naphtho[1,2-d]furan ring (also referred to as a Bnf skeleton), depending on the condensed position of the benzene ring. Specific structures of these skeletons are shown below. When the benzonaphthofuran ring shown below is substituted, one of the carbons or nitrogen atoms is a bond.

[0124]

[0125] When aromatic rings having a structural isomerism are used, the aBnf skeleton can be used as the material for the electron transport layer, the Bnf(II) skeleton can be used as the host material for the light-emitting layer, and the Bnf can be used as the material for the hole transport layer. Materials using aromatic rings having a structural isomerism have different properties (carrier transportability, HOMO, LUMO, etc.), so by using an aromatic ring appropriate for the properties required for each layer, it is possible to achieve the above-mentioned adjustment of Tg, reduction in raw material costs, shortening of synthesis steps, and improvement of properties.

[0126] It is also preferable that each host material in each light-emitting layer of the red, green, and blue elements contains aromatic rings that are structurally isomeric. When different materials are used for the hole transport layer materials of each color, aromatic rings that are structurally isomeric may be contained. When multiple electron transport layers are used, it is also preferable that the multiple layers contain aromatic rings that are structurally isomeric. The same applies to when multiple hole transport layers are used. Thus, it is preferable that multiple materials used in an organic device contain aromatic rings that are structurally isomeric. When structurally isomeric aromatic rings contain a fused ring structure, they can also be referred to as aromatic rings with the same molecular weight but different fused positions. This is not limited to benzonaphthofuran rings, but also applies to the other aromatic rings mentioned above (e.g., benzofluorene ring, benzoxanthene ring, spirobenzofluorenexanthene ring, benzocarbazole ring, benzonaphthothiophene ring). As described above, the term "benzonaphthofuran ring" includes structural isomers such as aBnf, Bnf(II), and Bnf, and similarly includes structural isomers of other fused rings.

[0127] Each fused ring in the structural formula may have a substituent. Different compounds may have the same substituent or different substituents.

[0128] Furthermore, the first light-emitting unit 501 and the second light-emitting unit may include other functional layers in addition to the aforementioned light-emitting layer, hole transport layer, electron transport layer, etc. The structure is not limited to that shown in Figure 1A, and any of the layers may be omitted, or other layers may be provided. Representative examples of such other layers include a carrier block layer and an exciton block layer.

[0129] The first electrode 101 is an electrode including an anode. The first electrode 101 may have a stacked structure, in which case the layer in contact with the organic compound layer 103 functions as the anode. The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof having a high 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, indium oxide-zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are usually formed by sputtering, but may also be formed by applying a sol-gel method or the like. For example, indium oxide-zinc oxide may be formed by sputtering using a target containing indium oxide and 1 to 20 wt % zinc oxide. 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 that can be 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), and nitrides of metal materials (e.g., titanium nitride). Alternatively, graphene can be used for the anode. Note that by using the composite material that forms the first layer 161 (also referred to as a P-type layer) in the intermediate layer 160 as a layer in contact with the anode (typically a hole-injection layer), electrode materials can be selected regardless of the work function.

[0130] 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 (first light-emitting unit 501). ２ The organic EL element can be formed from a phthalocyanine compound or complex compound such as copper phthalocyanine (abbreviated as CuPc), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) or 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS).

[0131] The hole-injection layer 111 may be formed using a substance having electron acceptor properties. Examples of the substance having acceptor properties include organic compounds having an electron-withdrawing group (such as a halogen group or a cyano group), such as 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-TCCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a fused aromatic ring having a plurality of heteroatoms, such as HAT-CN, are thermally stable and preferred. Also, [3]radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group, a cyano group, etc.) are preferred because they have very high electron-accepting properties, and specific examples thereof include α,α',α''-1,2,3-cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenetris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. 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 also be used as the acceptor material. ２The hole injection layer 111 can also be formed from a phthalocyanine compound or complex compound such as copper phthalocyanine (abbreviated as CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) or 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviated as DNTPD), or a polymer such as poly(3,4-ethylenedioxythiophene) / polystyrene sulfonic acid (abbreviated as PEDOT / PSS). A substance having acceptor properties can extract electrons from an adjacent hole transport layer (or hole transport material) when an electric field is applied.

[0132] The hole-injection layer 111 is preferably formed using a composite material containing the above-described material having an acceptor property and a substance having a hole-transport property.

[0133] As a substance having a hole transport 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. −６ cm ２ / Vs or more. The substance having hole transport properties used in the composite material is preferably a compound having a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. As the fused aromatic hydrocarbon ring, an anthracene ring, a naphthalene ring, or the like is preferable. As the π-electron-rich heteroaromatic ring, a fused 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 fused to one of these is preferable.

[0134] Such a substance having hole-transporting properties preferably has a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, the substance may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the substance having hole-transporting properties be a substance having an N,N-bis(4-biphenyl)amino group, since this allows the manufacture of a light-emitting device with a long lifetime.

[0135] Specific examples of the substance having the hole transport property 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)benzo[b]naphtho[1,2-d]furan-8-yl, and N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-yl. [b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]- N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβN B-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'-(3-phenyl-9H-carbazol-9-yl)biphenyl-4''-[ ... 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- 4,4'-diphenyl-4'-(9-phenyl-9H-carbazol-3-yl)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 N-(biphenyl-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-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluorene-4- amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-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, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz), 9'-phenyl-9'H-9,3':6',9"-tercarbazole (abbreviation: PSiCzGI), etc.

[0136] Other aromatic amine compounds that can be used as the substance having hole-transporting properties include 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).

[0137] By forming the hole injection layer 111, the hole injection property becomes good, and a light emitting device with a low driving voltage can be obtained.

[0138] Among substances having acceptor properties, organic compounds having acceptor properties are easy to use because they can be easily vapor-deposited and formed into a film.

[0139] The hole-transporting layers (the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2) are formed by containing an organic compound having a hole-transporting property. −６ cm ２ It is preferable that the organic compound has a hole mobility of 1 / Vs or more. In addition to the organic compounds having an amine skeleton and a fluorene skeleton described above, other organic compounds can be used as needed.

[0140] Examples of the substance having a 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-fluoren]-2-yl)-N,N′-diphenyl-4,4′-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4′-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), and 4-phenyl-3-methylphenyl-4,4′-diaminobiphenyl (abbreviation: 4,4′-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB). 4,4'-diphenyl-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: PCBA1BP), compounds having an aromatic amine 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), 3,3'-bis(9-phenyl-9H-carbazole) (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)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, compounds having a carbazole skeleton such as N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, and 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz); 4,4',4"-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II);Examples of suitable 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 compounds listed above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. The organic compounds listed as the substances having hole-transport properties used in the composite material of the hole-injection layer 111 can also be suitably used as materials for forming the hole-transport layer 112 (the first hole-transport layer 112_1 and the second hole-transport layer 112_2). Note that organic compounds obtained by appropriately deuterating the above-listed organic compounds can also be used in the same manner.

[0141] Note that the first hole-transporting layer 112_1 and the second hole-transporting layer 112_2 preferably contain an organic compound having the same skeleton, and more preferably contain the same compound.

[0142] The light-emitting layers (the first light-emitting layer 113_1 and the second light-emitting layer 113_2) preferably contain a light-emitting center substance and a host material. Note that the light-emitting layers may also contain other materials.

[0143] Furthermore, the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are preferably light-emitting layers that emit light of similar colors. For example, red, green, and blue pixels are often used in display devices to express full colors. In the case of a light-emitting device used for a red pixel, both the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are light-emitting layers that emit red light. In the case of a light-emitting device used for a green pixel, both the two light-emitting layers are light-emitting layers that emit green light. In the case of a blue pixel, both the first light-emitting layer 113_1 and the second light-emitting layer 113_2 emit blue light. In this case, the light-emitting center substance contained in the first light-emitting layer 113_1 and the light-emitting center substance contained in the second light-emitting layer 113_2 are preferably compounds whose difference in maximum peak wavelength in their emission spectra is 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less. It is more preferable that the light-emitting center substance contained in the first light-emitting layer 113_1 and the light-emitting center substance contained in the second light-emitting layer 113_2 are the same.

[0144] The luminescent center substance may be a fluorescent substance, a phosphorescent substance, a substance exhibiting thermally activated delayed fluorescence (TADF), or any other luminescent substance.

[0145] Examples of fluorescent substances that can be used as the luminescent center substance in the light-emitting layer include the following: In addition, fluorescent substances other than these can also be used.

[0146] 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 )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: 2PAPPA), 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-carbazole-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-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-pyra N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhTD), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine (abbreviation: p-mPhTD), 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), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJ™), N,N'-diphenyl-N,N'-(1,6-pyren-diyl)bis[(6-phenylbenzo[b]naphthyl)benzo[b]naphthyl] ... 6,7-b']bisbenzofuran-3,10-diamine (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, condensed aromatic diamine compounds, such as pyrene diamine compounds 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because they have high hole trapping properties and excellent luminous efficiency or reliability.

[0147] Examples of phosphorescent materials that can be used as the luminescent center material in the light-emitting layer include the following:

[0148] Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp) ３ ]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz) ３ ]), organometallic iridium complexes having a 4H-triazole skeleton such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp) ３]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me) ３ organometallic iridium complexes having a 1H-triazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpim) ３ ]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me) ３ organometallic iridium complexes having an imidazole skeleton, such as tris(2-{1-[2,6-bis(1-methylethyl)phenyl]-1H-imidazol-2-yl-κN}-4-cyanophenyl-κC)iridium(III) (abbreviation: CNImIr), tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC)phenyl-κC]iridium(III) (abbreviation: [Ir(cb) ３ organometallic complexes having 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(CF ３ ppy) ２ (pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C ２’Examples of suitable iridium complexes include organometallic iridium complexes having a phenylpyridine derivative having an electron-withdrawing group as a ligand, such as iridium(III) acetylacetonate (abbreviation: FIracac), and platinum complexes such as (2-{3-[3-(3,5-di-tert-butylphenyl)benzimidazol-1-yl-2-ylidene-κC2]phenoxy-κC2}-9-(4-tert-butyl-2-pyridinyl-κN)carbazole-2,1-diyl-κC1)platinum(II) (abbreviation: PtON-TBBI). These compounds exhibit blue phosphorescence and have an emission peak in the wavelength range of 450 nm to 520 nm. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0149] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ３ ]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ３ ]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm) ２ (acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm) ２ (acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm) ２ (acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm) ２ (acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm) ２ organometallic iridium complexes having a pyrimidine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me) ２(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr) ２ organometallic iridium complexes having a pyrazine skeleton, such as tris(2-phenylpyridinato-N,C(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-d ３ [5-methyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d ３ ) ２ (mbfpypy-d ３ )), {2-(methyl-d ３ )-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofuro[2,3-b]pyridin-7-yl-κC}bis{5-(methyl-d ３ )-2-[5-(methyl-d ３ )-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5mtpy-d6) ２ (mbfpypy-iPr-d ４ )), [2-d ３-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mbfpypy-d ３ )), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy) ２ (mdppy)), [2-(4-d ３ -methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(5-d ３ [Ir(5mppy-d-methyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(5mppy-d-methyl-2-pyridinyl-κN)phenyl-κC]iridium(III) ３ )2(mdppy-d ３ ) )]), [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)]), tris{2-[5-(methyl-d3)-4-phenyl-2-pyridinyl-κN]phenyl-κC}iridium(III) (abbreviation: Ir(5m4dppy-d ３ ) ３In addition to organometallic iridium complexes having a pyridine skeleton such as (2-{1-(5-tert-butylbiphenyl-2-yl)-4-[3-tert-butyl-5-(4-phenyl-2-pyridinyl-κN)phenyl-κC6]-2-benzimidazolyl-κN3}-4,6-di-tert-butylphenolato-κO)platinum(II) (abbreviation: Pt(tBudppymmtBubiz-tBubp)), [2-(4-(3,5-di- platinum complexes such as [Tb(acac)]-6-{3-[4-(5'-tert-butylphenyl)-2-pyridinyl-κN]phenyl-κC2}-2-pyridinyl-κN)phenolato-κO]platinum(II) (abbreviation: Pt(4tButppppypyp-mmtBup)); tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)] ３ Examples of suitable compounds include rare earth metal complexes such as iridium complexes containing iridium ions (Phen). These compounds are primarily compounds that exhibit green phosphorescence and have an emission peak in the wavelength range of 500 nm to 600 nm. Organometallic iridium complexes having a pyrimidine skeleton are particularly preferred because they are remarkably excellent in reliability and luminous efficiency. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0150] Also, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm) ２ (dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm) ２ (dpm)]), bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(dpm) ２ organometallic iridium complexes having a pyrimidine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr) ２(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr) ２ (dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq) ２ organometallic iridium complexes having a pyrazine skeleton, such as tris(1-phenylisoquinolinato-N,C(acac)]); ２’ ) Iridium(III) (abbreviation: [Ir(piq) ３ ]), bis(1-phenylisoquinolinato-N,C ２’ ) iridium(III) acetylacetonate (abbreviation: [Ir(piq) ２ (acac)]), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). In addition to organometallic iridium complexes having a pyridine skeleton such as [ru-κC]iridium(III), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(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 Examples of suitable compounds include rare earth metal complexes such as iridium fluoride (Phen). These compounds exhibit red phosphorescence and have an emission peak in the wavelength range of 600 nm to 700 nm. Organometallic iridium complexes having a pyrazine skeleton can emit red light with good chromaticity. Compounds in which some of the hydrogen atoms in these compounds are replaced with deuterium atoms can also be used.

[0151] In one embodiment of the present invention, the use of a deuterated compound as the luminescent center substance improves luminous efficiency, and therefore the luminescent center substance is preferably a deuterated material.

[0152] In addition to the phosphorescent compounds described above, known phosphorescent compounds may be selected and used.

[0153] Examples of TADF materials that can be used include fullerene and its derivatives, acridine and its derivatives, and eosin derivatives. Other examples include metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (SnF), which are represented by the following structural formula: ２ (Proto IX)), mesoporphyrin-tin fluoride complex (SnF ２ (Meso IX)), hematoporphyrin-tin fluoride complex (SnF ２ (Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF ２ (Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF ２ (OEP)), etioporphyrin-tin fluoride complex (SnF ２ (Etio I)), octaethylporphyrin-platinum chloride complex (PtCl ２ OEP) and the like.

[0154]

[0155] Further, 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), and 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[acridine-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, making it preferable. Among the skeletons having a π-electron-deficient heteroaromatic ring, pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptor properties and good reliability. Furthermore, among the skeletons having a π-electron-rich heteroaromatic ring, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable.The furan skeleton is preferably a dibenzofuran skeleton, and the thiophene skeleton is preferably a dibenzothiophene skeleton. 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. A substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferred 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 enhanced, reducing the energy difference between the S1 level and the T1 level, thereby enabling efficient thermally activated delayed fluorescence. Instead of the π-electron-deficient heteroaromatic ring, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used. The π-electron-rich skeleton may be, for example, an aromatic amine skeleton or a phenazine skeleton. Examples of usable π-electron-deficient skeletons 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.

[0156]

[0157] Alternatively, a TADF material in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used. Such a TADF material has a short emission lifetime (excitation lifetime), which can suppress a decrease in efficiency in the high-brightness region of a light-emitting device. Specific examples include materials with the molecular structure shown below.

[0158]

[0159] The TADF material is a material that has a small difference between the S1 level and the T1 level and has 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 (reverse intersystem crossing) with a small amount of thermal energy, and a singlet excited state can be efficiently generated. Furthermore, triplet excitation energy can be converted into luminescence.

[0160] Furthermore, an exciplex (also called an exciplex) that forms an excited state with two types of substances has an extremely small difference between the S1 level and the T1 level, and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy.

[0161] The T1 level can be determined by using a phosphorescence spectrum observed at low temperatures (for example, from 77 K to 10 K). When a tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side of the TADF material, and the energy of the wavelength of the extrapolated line is defined as the S1 level, and when a tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side of the TADF material, and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0162] 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.

[0163] As the host material of the light-emitting layer, various carrier transport materials such as a material having an electron transport property and / or a material having a hole transport property, and the above-mentioned TADF material can be used.

[0164] The material having hole transport properties is preferably an organic compound having an amine skeleton, a π-electron-rich heteroaromatic ring skeleton, etc. The π-electron-rich heteroaromatic ring is preferably a fused aromatic ring containing at least one of an acridine skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a furan skeleton, a thiophene skeleton, and a pyrrole skeleton in the ring, and specifically preferably a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is fused to one of these.

[0165] The hole-transporting substance preferably has a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, the hole-transporting substance may be an aromatic amine having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, an aromatic monoamine having a naphthalene ring, or an aromatic monoamine in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group. It is preferable that the hole-transporting substance be an organic compound having an N,N-bis(4-biphenyl)amino group, since this allows the fabrication of a light-emitting device with a long lifetime.

[0166] As such an organic compound, for example, the following organic compounds are preferable: 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 ... 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: PCBA1BP), )triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF), compounds having an aromatic amine 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), 3,3′-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 3,9-bis(9-phenyl-9H-carbazole-3-yl)-9H-carbazole (abbreviation: PCCzPC), 9-(biphenyl-4-yl)-9′-phenyl-3,3′-bi-9H-carbazole (abbreviation: PCCzBP), 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 Bicarbazole (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':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, )-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 Carbazole, 9-(4-biphenyl)-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, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine, 9-[3-(triphenylsilyl)phenyl]-3,9'-bi-9H-carbazole (abbreviation: PSiCzCz), 9'-phenyl-9'H-9,3':6',Compounds having a carbazole skeleton such as 9''-tercarbazole (abbreviation: PSiCzGI), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), Examples of suitable materials include compounds having a thiophene skeleton such as [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 a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. Furthermore, the organic compounds listed as examples of materials having hole transport properties for the hole transport layer can also be used.

[0167] The electron-transporting material is preferably an organic compound having a π-electron-deficient heteroaromatic ring. Examples of the organic compound having a π-electron-deficient heteroaromatic ring skeleton include 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.

[0168] Among these, 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 preferred because of their high 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 driving voltage. In addition, benzofuropyrimidine skeletons, benzothienopyrimidine skeletons, benzofuropyrazine skeletons, and benzothienopyrazine skeletons are preferred because of their high acceptor properties and high reliability.

[0169] As the organic compound having a π-electron-deficient heteroaromatic ring skeleton, for example, the following organic compounds are preferred: 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), and other organic compounds having an azole skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35 DCzPPy), 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 organic compounds containing a heteroaromatic ring having a pyridine 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 1-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 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: 9mDBtBPN fpr), 9-[3'-(dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(dibenzothiophen-4-yl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine 4,6mCzBP2Pm), 8-(biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazo phosphorus) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), 6-(biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2PPm), 2,6-bis(4-naphthalen-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 4-[ 3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(1,1':4',1''-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPB organic compounds having a diazine skeleton such as 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 (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: mTpB PTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), 2-(biphenyl-3-yl)-4-phenyl-6-{8-[(1,1':4',1''-terphenyl)-4-yl]-1-dibenzofuranyl}-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-[4-(2-naphthalenyl)phenyl]-4-phenyl-6-spiro[9H-fluorene-9,9'-[9H]xanthene]-4-yl-1,3,5-Triazine (abbreviation: βNP-SFx(4)Tzn), 9,9'-{6-[3-(triphenylsilyl)phenyl]-1,3,5-triazine-2,4-diyl}bis(9H-carbazole) (abbreviation: SiTrzCz2), 2-phenyl-4,6-bis[3-(triphenylsilyl)phenyl]-1,3,5-triazine (abbreviation: mSiTrz), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-(biphenyl-3-yl)indolo[2,3-a]carbazole (abbreviation: BP-mBPIcz(II)Tzn), 3-{3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuran

[0033] Examples of organic compounds containing a heteroaromatic ring having a triazine skeleton include organic compounds containing a heteroaromatic ring having a triazine skeleton, such as 9,9'-[6-(biphenyl-4-yl)-2-phenyl-1,3,5-triazine-4,3''-diyl]bis(9H-carbazole) (abbreviation: Cz-pmCzBPTzn), 3-phenyl-9-[4-phenyl-6-(9-phenyl-3-dibenzofuranyl)-1,3,5-triazin-2-yl]-9H-carbazole (abbreviation: PDBf-PCzTzn), and 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzothienyl]-2-phenyl-9H-carbazole (abbreviation: PCzDBtTzn). In addition, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred because of their high 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 driving voltage.

[0170] The TADF materials usable as host materials can be the same as those listed above as TADF materials usable as luminescent center substances. When a TADF material is used as a host material, triplet excitation energy generated in the TADF material is converted into singlet excitation energy by reverse intersystem crossing, and the energy is further transferred to the luminescent material, thereby improving the luminous efficiency of the light-emitting device. In this case, the TADF material functions as an energy donor, and the luminescent material functions as an energy acceptor.

[0171] This is very effective when the luminescent material is a fluorescent luminescent material. Furthermore, in this case, in order to obtain high luminous efficiency, it is preferable that the S1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Furthermore, it is preferable that the T1 level of the TADF material is higher than the S1 level of the fluorescent luminescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than the T1 level of the fluorescent luminescent material.

[0172] 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, since this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient light emission.

[0173] Furthermore, in order to efficiently generate singlet excitation energy from triplet excitation energy through reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent material. To this end, it is preferable that the fluorescent material has a protecting group around the luminophore (the skeleton responsible for light emission) possessed by the fluorescent material. The protecting group is preferably a substituent without a π bond, and is preferably a saturated hydrocarbon. Specific examples include alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable that the protecting group has multiple protecting groups. Substituents without a π bond have poor carrier transport function, so the distance between the TADF material and the luminophore of the fluorescent material can be increased without significantly affecting carrier transport or carrier recombination. Here, the luminophore refers to the atomic group (skeleton) responsible for 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 fused aromatic ring or a fused heteroaromatic ring. Examples of such luminophores include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, a phenothiazine skeleton, a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, and a naphthobisbenzofuran skeleton. In particular, fluorescent materials having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because of their high fluorescence quantum yield.

[0174] When a fluorescent substance is used as the emission center substance, a material having an anthracene skeleton is suitable as the host material. Using a substance having an anthracene skeleton as the host material for a fluorescent substance makes it possible to realize an emission layer with both excellent luminous efficiency and durability. As a substance having an anthracene skeleton used as the host material, a diphenylanthracene skeleton, particularly a substance having a 9,10-diphenylanthracene skeleton, is preferred because it is chemically stable. Furthermore, a host material having a carbazole skeleton is preferred because it enhances hole injection and transport properties. However, a host material containing a benzocarbazole skeleton in which a benzene ring is further condensed to carbazole is more preferred because its HOMO is about 0.1 eV higher than that of the carbazole skeleton, making it easier for holes to enter. In particular, a host material containing a dibenzocarbazole skeleton is preferred because its HOMO is about 0.1 eV higher than that of the 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). Note that, in view 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 Examples include 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 exhibit very good properties.

[0175] The host material may be a mixture of multiple substances. When a mixture of host materials is used, it is preferable to mix a material having electron-transporting properties with a material having hole-transporting properties. By mixing a material having electron-transporting properties with a material having hole-transporting properties, the transport properties of the light-emitting layer 113 (the first light-emitting layer 113_1 and the second light-emitting layer 113_2) can be easily adjusted, and the recombination region can also be easily controlled. The weight ratio of the content of the material having hole-transporting properties to the material having electron-transporting properties may be 1:19 to 19:1 (material having hole-transporting properties:material having electron-transporting properties).

[0176] A phosphorescent material can be used as 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.

[0177] These mixed materials may also form an exciplex. The exciplex is preferably selected from 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 allows for smooth energy transfer and efficient light emission. Furthermore, this configuration is also preferable because it reduces the driving voltage.

[0178] At least one of the materials forming the exciplex may be a phosphorescent material, which allows efficient conversion of triplet excitation energy into singlet excitation energy through reverse intersystem crossing.

[0179] 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. Also, it is 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. Note that 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).

[0180] The formation of exciplexes can be confirmed, for example, by comparing the emission spectra of a material with hole transport properties, a material with electron transport properties, and a mixed film obtained by mixing these materials, and observing the phenomenon in which the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak at longer wavelengths). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a material with hole transport properties, the transient PL of a material with electron transport properties, and a mixed film obtained by mixing these materials, and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lifetime component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL may also be interpreted as transient electroluminescence (EL). In other words, the formation of exciplexes can also be confirmed by comparing the transient EL of a material with hole transport properties, the transient EL of a material with electron transport properties, and a mixed film obtained by mixing these materials, and observing the differences in transient response.

[0181] The first electron-transporting layer 114_1 is a layer containing a substance having an electron-transporting property. The material having an electron-transporting property is a material having an electron mobility of 1×10 or less 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 preferred. Note that, other substances can be used as long as they have a higher electron transport property than holes. Note that, as the organic compound, an organic compound having a π-electron-deficient heteroaromatic ring is preferred. As the organic compound having a π-electron-deficient heteroaromatic ring, for example, one or more of an organic compound including a heteroaromatic ring having an azole skeleton, an organic compound including a heteroaromatic ring having a pyridine skeleton, an organic compound including a heteroaromatic ring having a diazine skeleton, and an organic compound including a heteroaromatic ring having a triazine skeleton are preferred, and triazine is particularly preferred.

[0182] As the organic compound having electron-transporting properties that can be used in the first electron-transporting layer 114_1, organic compounds that can be used as the organic compound having electron-transporting properties of the host material in the first light-emitting layer 113_1 and the second light-emitting layer 113_2 can be used as well. Among them, organic compounds including a heteroaromatic ring having a diazine skeleton, an organic compound including a heteroaromatic ring having a pyridine skeleton, and an organic compound including a heteroaromatic ring having a triazine skeleton are preferred because of their high reliability. In particular, organic compounds including a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton and organic compounds including a heteroaromatic ring having a triazine skeleton have high electron-transporting properties and contribute to reducing driving voltage.

[0183] As described above, the second electron-transporting layer 114_2 is a layer including an organic compound having a triazine skeleton. Details thereof have already been described, so they will not be described again.

[0184] Note that the first electron-transport layer 114_1 preferably contains an organic compound having a triazine skeleton in order to reduce power consumption. In particular, it is preferable that the first electron-transport layer 114_1 contains the same organic compound having a triazine skeleton as the organic compound having a triazine skeleton contained in the second electron-transport layer 114_2, because this prevents the manufacturing apparatus from becoming complicated and is advantageous in terms of raw material procurement costs.

[0185] Furthermore, since the first electron-transport layer 114_1 contains an organic compound that does not contain a triazine skeleton, it becomes easier to control the carrier transport property, and a light-emitting device with better characteristics can be provided. As the organic compound that does not contain a triazine skeleton, an organic compound that contains a heteroaromatic ring having a pyridine skeleton or an organic compound that contains a heteroaromatic ring having a diazine (pyrimidine or pyrazine) skeleton is preferable.

[0186] The intermediate layer 160 is a layer containing an organic compound having a phenanthroline skeleton. As shown in FIG. 1A , the intermediate layer 160 preferably includes a first layer 161 containing an organic compound having a phenanthroline skeleton. The intermediate layer 160 also preferably includes a second layer 162 containing a compound having hole transport properties and a substance having acceptor properties. The second layer 162 is located closer to the second electrode 102 than the first layer 161. The intermediate layer 160 may also include a third layer 163 between the first layer 161 and the second layer 162.

[0187] The details of the first layer have been described above, so a repeated description will be omitted.

[0188] Note that the first layer 161 may further contain an organic compound having electron-transporting properties. Examples of organic compounds having electron-transporting properties that can be used for the organic compound include the organic compounds that can be used as the organic compounds having electron-transporting properties of the host materials in the first light-emitting layer 113_1 and the second light-emitting layer 113_2. Furthermore, it is preferable to use, as the organic compound, an organic compound having two or more heteroaromatic rings bonded to or condensed with each other, and the two or more heteroaromatic rings having three or more heteroatoms in total, because this can further improve resistance to photolithography and suppress an increase in driving voltage.

[0189] The first layer 161 may have a stacked structure of a layer containing an organic compound and a layer having a metal or a metal compound located closer to the cathode than the layer containing the organic compound, or may be a mixed layer of an organic compound and a metal or a metal compound. A mixed layer is preferable because it requires fewer deposition chambers and reduces manufacturing costs, and also contributes to improving the stability of the light-emitting device.

[0190] When an organic compound and a metal or metal compound are mixed, the distribution of the organic compound and the distribution of the metal or metal compound show roughly the same tendency when the first layer 161 is analyzed in the film thickness direction. That is, when the distribution of the organic compound is constant, the distribution of the metal or metal compound is also roughly constant. In the case of a laminated structure of an organic compound and a layer containing a metal or metal compound, the metal or metal compound may be detected in regions other than the layer containing the metal or metal compound due to diffusion from the layer containing the metal or metal compound, but since the distribution shows a different distribution from the distribution of the organic compound, the analysis results can be distinguished as diffusion or mixing.

[0191] The second layer 162 preferably contains an organic compound having a hole-transporting property. The second layer 162 preferably further contains a substance exhibiting an acceptor property, and the substance exhibiting an acceptor property is preferably an organic compound exhibiting an acceptor property to the organic compound having a hole-transporting property.

[0192] When the second layer 162 is a layer containing an organic compound having a hole-transport property and a substance that exhibits acceptor properties for the organic compound having a hole-transport property, holes are generated by charge separation, and when a voltage is applied between the first electrode 101 and the second electrode 102, the holes are injected into the first light-emitting unit 501 on the cathode side via the organic compound having a hole-transport property. Thus, the light-emitting device 130 of one embodiment of the present invention can be a light-emitting device with low driving voltage.

[0193] As the organic compound having hole transport properties, various organic compounds such as aromatic amine compounds, heteroaromatic compounds, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. −６ cm ２Preferably, the organic compound has a hole mobility of 1 / Vs or more. Furthermore, the organic compound having hole transport properties is preferably a compound having a fused aromatic hydrocarbon ring or a π-electron-rich heteroaromatic ring. The fused aromatic hydrocarbon ring is preferably an anthracene ring, a naphthalene ring, or the like. Furthermore, the π-electron-rich heteroaromatic ring is preferably a fused aromatic ring containing at least one of a pyrrole skeleton, a furan skeleton, and a thiophene skeleton, and specifically, a carbazole ring, a dibenzothiophene ring, or a ring in which an aromatic ring or a heteroaromatic ring is fused to one of these.

[0194] 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, 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 may be used. It is preferable that these organic compounds having hole transport properties are substances having an N,N-bis(4-biphenyl)amino group, since this allows the fabrication of light-emitting devices with a long lifetime.

[0195] Specifically, as the organic compound having a hole-transport property as described above, the organic compounds exemplified as the organic compounds having a hole-transport property that can be used for the hole-injection layer 111 can be similarly used.

[0196] As the substance having acceptor properties, for example, the substances exemplified as organic compounds having acceptor properties that can be used in the hole-injection layer 111 can be similarly used. In particular, an organic compound having at least one of a halogen group and a cyano group is preferable, and an organic compound having at least one of a fluorine group and a cyano group is more preferable. It is more preferable that the organic compound contains four or more halogen groups (fluorine) and cyano groups in total. Examples of organic compounds having at least one of a halogen group and a cyano group 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].

[0197] It is preferable that the material having acceptor properties has electron accepting properties for the organic compound having hole transport properties. When the material having acceptor properties has electron accepting properties for the organic compound having hole transport properties, charge separation occurs, and the second layer 162 can function as a charge generating layer and as a tandem intermediate layer. It is also preferable that the second layer 162 exhibits a signal observed by electron spin resonance. For example, the spin density resulting from a signal observed around 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.

[0198] The third layer 163 contains a substance having an electron transporting property, and has functions such as preventing an interaction between the first layer 161 and the second layer 162, smoothing the transfer of electrons to reduce the driving voltage, and reducing the interaction between the first layer 161 and the second layer 162 to improve reliability.

[0199] The LUMO level of the substance having electron-transporting properties contained in the third layer 163 is preferably between the LUMO level of the substance having acceptor properties in the second layer 162 and the LUMO level of the organic compound contained in the layer in contact with the first layer 161 in the light-emitting unit on the anode side (the first electron-transporting layer 114_1 in the first light-emitting unit 501 in FIG. 1A ).

[0200] The specific energy level of the LUMO level of the substance having an electron-transporting property used for the third layer 163 is preferably −5.0 eV or higher, preferably −5.0 eV or higher to −3.0 eV or lower, more preferably −4.30 eV or higher to −3.00 eV or lower, and more preferably −4.30 eV or higher to −3.30 eV or lower, in order to suppress an increase in driving voltage. Note that the substance having an electron-transporting property used for the third layer 163 is preferably a phthalocyanine-based material or a metal complex having a metal-oxygen bond and an aromatic ligand.

[0201] Specific examples of the substance having an electron-transporting property that can be used for the third layer 163 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 tetracarboxylic bis-benzimidazole (abbreviation: PTCBI), (C60-Ih)[5,6]fullerene (abbreviation: C60), and (C70-D5h)[5,6]fullerene (abbreviation: C70). Furthermore, a compound having a heterophane skeleton, which is a cyclophane skeleton containing a heterocycle, can be used. Examples of such a compound include phthalocyanine (abbreviation: H ２Phthalocyanine compounds such as copper phthalocyanine (abbreviated as CuPc), zinc phthalocyanine (abbreviated as ZnPc), cobalt phthalocyanine (abbreviated as CoPc), iron phthalocyanine (abbreviated as FePc), tin phthalocyanine (abbreviated as SnPc), tin oxide phthalocyanine (abbreviated as SnOPc), titanium oxide phthalocyanine (abbreviated as TiOPc), vanadium oxide phthalocyanine (abbreviated as VOPc), and their derivatives can also be used. Phthalocyanine-based metal complexes such as copper phthalocyanine or zinc phthalocyanine, or 2,3,8,9,14,15-hexafluorodiquinoxalino[2,3-a:2',3'-c]phenazine are particularly preferred.

[0202] The thickness of the third layer 163 is preferably 1 nm or more and 10 nm or less, more preferably 2 nm or more and 5 nm or less.

[0203] Since the second layer 162 in the intermediate layer 160 functions as a hole injection layer, the second light-emitting unit 502 does not have a hole injection layer, but the second light-emitting unit 502 may have a hole injection layer.

[0204] 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, alloy, electrically conductive compound, or mixture thereof having a small work function (specifically, 3.8 eV or less) can be used. Specific examples of such cathode materials include alkali metals such as lithium (Li) or cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), and alloys containing these elements (Mg ｘ Ag ｙ , Al ｘ Li ｙ(x and y are any integers), europium (Eu), ytterbium (Yb), and other rare earth metals, as well as alloys containing these metals. Specific examples include lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF ２ Examples of the electride include alkali metals, alkaline earth metals, rare earth metals, such as lithium (8-quinolinolato) (abbreviation: Liq), and ytterbium (Yb), or compounds or complexes thereof, or electrides. Examples of the electride include a substance in which electrons are highly concentrated in a mixed oxide of calcium and aluminum. Two or more of these may be mixed and used. When the second electrode 102 has a stacked structure, materials with good conductivity can be used for the layers other than the cathode, regardless of their work functions.

[0205] Note that the second electron-transport layer 114_2 is preferably in contact with the second electrode 102. When the second electron-transport layer 114_2 is in contact with the second electrode 102, a light-emitting device having excellent electron-injection and electron-transport properties, low driving voltage, and low power consumption can be provided.

[0206] Note that when the second electrode 102 is formed using a material that is transparent to visible light, a light-emitting device that emits light from the second electrode 102 side can be obtained.

[0207] These conductive materials can be formed into films by dry methods such as vacuum deposition or sputtering, inkjet methods, spin coating methods, etc. Alternatively, they may be formed by wet methods using a sol-gel method, or by wet methods using a paste of a metal material.

[0208] In addition, various methods, whether dry or wet, can be used to form the organic compound layer 103. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, spin coating, or the like may be used.

[0209] Furthermore, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0210] FIG. 2 shows two adjacent light-emitting devices (light-emitting device 130a and light-emitting device 130b) included in a display device of one embodiment of the present invention.

[0211] The light-emitting device 130a includes an organic compound layer 103a between a first electrode 101a and a second electrode 102 on an insulating layer 175. The organic compound layer 103a includes a first light-emitting unit 501a and a second light-emitting unit 502a, sandwiching an intermediate layer 160a therebetween. While FIG. 2 illustrates an example in which two light-emitting units are stacked, a structure in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501a includes a hole-injection layer 111a, a first hole-transport layer 112a_1, a first light-emitting layer 113a_1, and a first electron-transport layer 114a_1. The intermediate layer 160a includes a second layer 162a, a third layer 163a, and a first layer 161a. The third layer 163a is optional. The second light-emitting unit 502a includes a second hole-transporting layer 112a_2, a second light-emitting layer 113a_2, and a second electron-transporting layer 114a_2.

[0212] The light-emitting device 130b includes an organic compound layer 103b between a first electrode 101b and a second electrode 102 on an insulating layer 175. The organic compound layer 103b includes a first light-emitting unit 501b and a second light-emitting unit 502b stacked with an intermediate layer 160b sandwiched therebetween. While FIG. 2 illustrates an example in which two light-emitting units are stacked, a structure in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501b includes a hole-injection layer 111b, a first hole-transport layer 112b_1, a first light-emitting layer 113b_1, and a first electron-transport layer 114b_1. The intermediate layer 160b includes a second layer 162b, a third layer 163b, and a first layer 161b. The third layer 163b is optional. The second light-emitting unit 502b includes a second hole-transporting layer 112b_2, a second light-emitting layer 113b_2, and a second electron-transporting layer 114b_2.

[0213] The first hole transport layer 112 a_1 and the second hole transport layer 112 a_2 have a stacked structure, and the organic compound used in the layer in contact with the light-emitting layer is formed using a material whose LUMO level is higher than the LUMO level of the material constituting the light-emitting layer (at least the host material, preferably the material constituting the light-emitting layer, the material having the largest constituent ratio among the materials constituting the light-emitting layer, or the material having the highest LUMO level among the materials constituting the light-emitting layer).

[0214] The second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are layers containing an organic compound having a triazine skeleton. The first layer 161a and the first layer 161b are layers containing an organic compound having a phenanthroline skeleton.

[0215] The first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are preferably light-emitting layers that emit light of similar colors. Furthermore, the luminescent center substances contained in each layer are preferably compounds whose emission spectra have a difference in maximum peak wavelength of 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less, and it is even more preferable that the luminescent center substances contained in each layer are the same. The first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are preferably light-emitting layers that emit light of similar colors. Furthermore, the luminescent center substances contained in each layer are preferably compounds whose emission spectra have a difference in maximum peak wavelength of 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less, and it is even more preferable that the luminescent center substances contained in each layer are the same.

[0216] It is preferable that the first light-emitting layer 113a_1 and the first light-emitting layer 113b_1 are separated, and the second light-emitting layer 113a_2 and the second light-emitting layer 113b_2 are separated. It is preferable that the emission colors of the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are different from the emission colors of the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2. It is preferable that the luminescent center substance contained in the first light-emitting layer 113a_1 is different from the luminescent center substance contained in the first light-emitting layer 113b_1, and that the luminescent center substance contained in the second light-emitting layer 113a_2 is different from the luminescent center substance contained in the second light-emitting layer 113b_2.

[0217] The hole injection layer 111a and the hole injection layer 111b, the first hole transport layer 112a_1 and the first hole transport layer 112b_1, the first electron transport layer 114a_1 and the first electron transport layer 114b_1, the intermediate layer 160a and the intermediate layer 160b (the second layer 162a and the second layer 162b, the third layer 163a and the third layer 163b, and the first layer 161a and the first layer 161b), the second hole transport layer 112a_2 and the second hole transport layer 112b_2, and the second electron transport layer 114a_2 and the second electron transport layer 114b_2 may each be a continuous layer, or may be independently separated in the light-emitting device 130a and the light-emitting device 130b. Being continuous layers improves productivity and enables light-emitting devices to be manufactured at low cost. The separate layers for each light-emitting device allow the use of materials suited to the emission color, thereby enabling the manufacture of a light-emitting device or display device with excellent characteristics. In particular, the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are preferably continuous layers, because this allows both the light-emitting device 130a and the light-emitting device 130b to have excellent characteristics.

[0218] Being a continuous layer means that the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are layers formed of the same material. That is, when the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 are layers formed of the same material, both the light-emitting device 130a and the light-emitting device 130b can be light-emitting devices with excellent characteristics. Furthermore, it is more preferable that the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 be layers having similar structures, and it is even more preferable that they be layers having the same structure.

[0219] Furthermore, the luminescent center substance contained in the first light-emitting layer 113a_1 is different from the luminescent center substance contained in the first light-emitting layer 113b_1, and the luminescent center substance contained in the second light-emitting layer 113a_2 is different from the luminescent center substance contained in the second light-emitting layer 113b_2 (for example, when the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are blue fluorescent light-emitting layers and the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2 are green phosphorescent light-emitting layers, or For example, when the first and second light-emitting layers 113a_1 and 113a_2 are blue fluorescent light-emitting layers and the first and second light-emitting layers 113b_1 and 113b_2 are red phosphorescent light-emitting layers, or when the first and second light-emitting layers 113a_1 and 113a_2 are green phosphorescent light-emitting layers and the first and second light-emitting layers 113b_1 and 113b_2 are red phosphorescent light-emitting layers, the carrier balances of the light-emitting layers of the light-emitting devices 130a and 130b are different. Therefore, in order to maximize the performance of each of the light-emitting devices 130a and 130b, appropriate intermediate layers and electron-transporting layers must be selected and changed for each device. However, by using layers containing an organic compound having a triazine skeleton for the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 and using layers containing an organic compound having a phenanthroline skeleton for the first layer 161a and the first layer 161b, it is possible to obtain the performance of both the light-emitting device 130a and the light-emitting device 130b even if the second electron-transporting layer 114a_2 and the second electron-transporting layer 114b_2 have the same structure. In other words, it is possible to achieve both improved productivity and improved performance. Note that the first layer 161a and the first layer 161b may have the same structure.

[0220] The continuous layer is a so-called common layer formed across both the light-emitting device 130a and the light-emitting device 130b.

[0221] 3A is a modified example of FIG. 2. Light-emitting device 130a and light-emitting device 130b emit light of different colors, and therefore have different optical path lengths between electrodes that can amplify light emission using a microcavity. Therefore, in light-emitting device 130b1, the distance between the electrodes can be adjusted by increasing the thickness of light-emitting layers such as light-emitting layer 113b_11 and light-emitting layer 113b_21. Alternatively, the optical path length may be changed by thickening or adding a functional layer, such as hole-transport layer 112b_21.

[0222] FIG. 3B shows three adjacent light-emitting devices (light-emitting device 130a, light-emitting device 130b1, and light-emitting device 130c) included in a display device according to one embodiment of the present invention.

[0223] The light-emitting device 130c includes an organic compound layer 103c between a first electrode 101c and a second electrode 102 on an insulating layer 175. The organic compound layer 103c includes a first light-emitting unit 501c and a second light-emitting unit 502c stacked with an intermediate layer 160c sandwiched therebetween. While FIG. 3B illustrates an example in which two light-emitting units are stacked, a configuration in which three or more light-emitting units are stacked may also be used. The first light-emitting unit 501c includes a hole-injection layer 111c, a first hole-transport layer 112c_1, a first light-emitting layer 113c_1, and a first electron-transport layer 114c_1. The intermediate layer 160c includes a second layer 162c, a third layer 163c, and a first layer 161c. The third layer 163c is optional. The second light-emitting unit 502c includes a second hole-transporting layer 112c_2, a second light-emitting layer 113c_2, and a second electron-transporting layer 114c_2.

[0224] The light-emitting device 130c is assumed to emit light with a shorter wavelength than the light-emitting devices 130a and 130b1. The inter-electrode distance of the light-emitting device 130c is adjusted by making the film thicknesses of the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 thinner than the light-emitting layers of the other two light-emitting devices.

[0225] The second electron-transporting layer 114c_2 is a layer containing an organic compound having a triazine skeleton. The first layer 161c is a layer containing an organic compound having a phenanthroline skeleton.

[0226] The first light-emitting layer 113c_1 and the second light-emitting layer 113c_2 are preferably light-emitting layers that emit light of similar colors. The luminescent center substances contained in each of the first and second light-emitting layers are preferably compounds whose difference in maximum peak wavelength in their emission spectra is 30 nm or less, more preferably 20 nm or less, and even more preferably 10 nm or less, and it is even more preferable that the luminescent center substances contained in each of the first and second light-emitting layers are the same.

[0227] It is preferable that the first light-emitting layer 113a_1 and the first light-emitting layer 113c_1 are separated, and the second light-emitting layer 113a_2 and the second light-emitting layer 113c_2 are separated. It is preferable that the emission colors of the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2 are different from the emission colors of the first light-emitting layer 113c_1 and the second light-emitting layer 113c_2. It is preferable that the luminescent center substance contained in the first light-emitting layer 113a_1 is different from the luminescent center substance contained in the first light-emitting layer 113c_1, and that the luminescent center substance contained in the second light-emitting layer 113a_2 is different from the luminescent center substance contained in the second light-emitting layer 113c_2.

[0228] In the example shown, the hole injection layer 111a and the hole injection layer 111c, the first hole transport layer 112a_1 and the first hole transport layer 112c_1, the first electron transport layer 114a_1 and the first electron transport layer 114c_1, the intermediate layer 160a and the intermediate layer 160c (the second layer 162a and the second layer 162c, the third layer 163a and the third layer 163c, and the first layer 161a and the first layer 161c), the second hole transport layer 112a_2 and the second hole transport layer 112c_2 are independently separated in the light-emitting device 130a and the light-emitting device 130c, while the second electron transport layer 114a_2 and the second electron transport layer 114c_2 are continuous layers. In this way, one light-emitting device may include both continuous layers and separate layers. This allows a light-emitting device or a display device with a good balance between productivity and characteristics to be manufactured. In particular, the second electron-transporting layer 114a_2 and the second electron-transporting layer 114c_2 are preferably formed as a continuous layer, because this allows both the light-emitting device 130a and the light-emitting device 130b to have good characteristics.

[0229] For example, in a three-color light-emitting device having two light-emitting devices with fluorescent luminescent center substances and one light-emitting device with phosphorescent luminescent center substances, it is preferable that the carrier transport layer in the light-emitting device with fluorescent luminescent center substances be formed as a continuous layer, and that the carrier transport layer in the light-emitting device with phosphorescent luminescent center substances be formed as a layer separated from the light-emitting devices emitting other luminescent colors. Alternatively, in a three-color light-emitting device having two light-emitting devices with phosphorescent luminescent center substances and one light-emitting device with fluorescent luminescent center substances, it is preferable that the carrier transport layer in the light-emitting device with phosphorescent luminescent center substances be formed as a continuous layer, and that the carrier transport layer in the light-emitting device with fluorescent luminescent center substances be formed as a layer separated from the light-emitting devices emitting other luminescent colors.

[0230] A light-emitting device of one embodiment of the present invention will be described with reference to Fig. 4. Fig. 4 is a schematic diagram of a light-emitting device 130a and a light-emitting device 130b, which are two adjacent light-emitting devices formed on the same insulating surface and are included in the light-emitting device, which is a modification of the light-emitting device described in Fig. 2 and Fig. 3.

[0231] The light-emitting device 130a is located on an insulating layer 175 and includes a first electrode 101a including an anode, a second electrode 102 including a cathode, and an organic compound layer 103a. The organic compound layer 103a is located between the first electrode 101a and the second electrode 102. The organic compound layer 103a has a configuration in which a first light-emitting unit 501a and a second light-emitting unit 502a are stacked with an intermediate layer 160a sandwiched therebetween.

[0232] The first light-emitting unit 501a includes a first hole-transport layer 112a_1 (hole-transport layer 112a_1a and hole-transport layer 112a_1b), a first light-emitting layer 113a_1, and a first electron-transport layer 114a_1. The intermediate layer 160a includes a first layer 161a and a second layer 162a. The second light-emitting unit 502a includes a second hole-transport layer 112a_2 (hole-transport layer 112a_2a and hole-transport layer 112a_2b), a second light-emitting layer 113a_2, a second electron-transport layer 114a_2, and an electron-injection layer 115. Therefore, it can be said that the intermediate layer 160a is located between the first light-emitting layer 113a_1 and the second light-emitting layer 113a_2.

[0233] In the light-emitting device 130a, the first light-emitting unit 501a preferably includes a hole-injection layer 111a. The intermediate layer 160a may include a third layer 163a between the first layer 161a and the second layer 162a. When the anode-side surface of the light-emitting unit is in contact with the intermediate layer 160a, as in the case of the second light-emitting unit 502a, the second layer 162a of the intermediate layer 160a located on the cathode side can also serve as the hole-injection layer for the second light-emitting unit 502a. Therefore, the hole-injection layer 111 may not be provided in the light-emitting unit. In other words, the hole-injection layer 111 may be provided as needed to achieve the desired performance of the light-emitting device.

[0234] Here, the light-emitting device 130b may have a different structure from the light-emitting device 130a. For example, the light-emitting device 130b shown in FIG. 4 has a different structure from the light-emitting device 130a in the first hole-transport layer 112a_1 and the second hole-transport layer 112a_2. When different light-emitting materials are used for the light-emitting layers of the light-emitting device 130a and the light-emitting device 130b, it is preferable to prepare an appropriate layer structure according to each light-emitting material. By separately preparing a structure for each light-emitting device so as to obtain optimal characteristics, the characteristics of the light-emitting device as a whole can be improved.

[0235] The light-emitting device 130b is located on the insulating layer 175 and includes a first electrode 101b including an anode, a second electrode 102 including a cathode, and an organic compound layer 103b. The organic compound layer 103b is located between the first electrode 101b and the second electrode 102. The organic compound layer 103b has a configuration in which a first light-emitting unit 501b and a second light-emitting unit 502b are stacked with an intermediate layer 160b sandwiched therebetween.

[0236] The first light-emitting unit 501b includes a first light-emitting layer 113b_1. The intermediate layer 160b includes a first layer 161b and a second layer 162b. The second light-emitting unit 502b includes a second light-emitting layer 113b_2 and an electron-injection layer 115. It can be said that the intermediate layer 160b is located between the first light-emitting layer 113b_1 and the second light-emitting layer 113b_2.

[0237] In the light-emitting device 130b, the first light-emitting unit 501b preferably includes a hole-injection layer 111b, a first hole-transport layer 112b_1, and a first electron-transport layer 114b_1 in addition to the first light-emitting layer 113b_1. The second light-emitting unit 502b preferably includes a second hole-transport layer 112b_2 and a second electron-transport layer 114b_2 in addition to the second light-emitting layer 113b_2 and the electron-injection layer 115. The intermediate layer 160b can include a third layer 163b between the first layer 161b and the second layer 162b. In addition, when the anode-side surface of the light-emitting unit is in contact with the intermediate layer 160b, as in the second light-emitting unit 502b, the second layer 162b of the intermediate layer 160b located on the cathode side can also serve as the hole-injection layer for the second light-emitting unit 502b, and therefore the light-emitting unit may not be provided with the hole-injection layer 111. In other words, the hole-injection layer 111 may be provided as necessary for the desired performance of the light-emitting device.

[0238] Note that the light-emitting device according to one embodiment of the present invention does not necessarily have to include a light-emitting device having the configuration shown in light-emitting device 130b, and may include a plurality of light-emitting devices having the configuration shown in light-emitting device 130a. When the configuration of the light-emitting devices is standardized in the light-emitting device, the complexity of the manufacturing apparatus can be reduced.

[0239] Although Figure 4 shows an example in which each organic compound layer contains two light-emitting units, one embodiment of the present invention is not limited to this. Each organic compound layer may contain three or more light-emitting units. By stacking multiple light-emitting units between a pair of electrodes with an intermediate layer sandwiched therebetween, a highly reliable light-emitting device can be realized, which can emit light with high luminance while maintaining a low current density. Furthermore, a light-emitting device with low power consumption can be realized.

[0240] Furthermore, the light-emitting device 130, the light-emitting device 130a, or the light-emitting device 130b may be a light-emitting device fabricated using, for example, a lithography method. That is, the light-emitting device 130, and the light-emitting devices 130a and 130b can each be fabricated by processing a portion of an organic compound layer using a lithography method. In the case of a light-emitting device fabricated using a lithography method, at least the first light-emitting layer 113_1 and the second light-emitting layer 113_2 and the organic compound layer provided closer to the first electrode 101 than the first light-emitting layer 113_1 and the second light-emitting layer 113_2 are processed simultaneously, so that their ends are substantially on the same plane in the vertical direction.

[0241] A light-emitting device of the present invention having such a structure can be a light-emitting device with high current efficiency, low energy loss, and favorable characteristics. A display device according to one embodiment of the present invention using such a light-emitting device can be a display device with low power consumption, high reliability, and high luminance, and thus has favorable visibility. This embodiment can be freely combined with other embodiments.

[0242] The above structure provides particularly significant benefits when used in a multi-layer tandem element according to one embodiment of the present application. As will be described later, multi-layer tandem elements have different layer structures for the red, green, and blue elements, and because they are stacked, the types and amounts of materials used are large. Therefore, by using the same fused rings in multiple layers, or by using the same fused rings bonded at different positions, or by using fused rings that are structural isomers, as described above, not only can manufacturing benefits such as reduced raw material costs and simplified synthesis steps be achieved, but physical property benefits such as adjustment of Tg or carrier transport properties can also be achieved. Furthermore, by using such materials in a multi-layer tandem element according to one embodiment of the present application, a light-emitting device suitable for mass production can be realized.

[0243] (Embodiment 2) In this embodiment, a display device manufactured using the light-emitting device described in Embodiment 1 will be described with reference to Fig. 5. Fig. 5A is a top view showing the display device, and Fig. 5B is a cross-sectional view taken along lines A-B and C-D in Fig. 5A. This display device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, to control light emission from the light-emitting device. Also, 604 is a sealing substrate, 605 is a sealant, and the inside surrounded by the sealant 605 is a space 607.

[0244] The routing wiring 608 is wiring for transmitting signals input to the source line driver circuit 601 and the gate line driver circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from an FPC (flexible print circuit) 609, which serves as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. In this specification, the display device includes not only the display device itself, but also a state in which an FPC or PWB is attached to it.

[0245] Next, the cross-sectional structure will be described with reference to Fig. 5B. A driver circuit section and a pixel section are formed on an element substrate 610, but here, a source line driver circuit 601, which is the driver circuit section, and one pixel in a pixel section 602 are shown.

[0246] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or the like, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like.

[0247] The structure of the transistors used in the pixels and the driver circuits is not particularly limited. For example, they may be inverted staggered transistors or staggered transistors. Furthermore, they may be top-gate or bottom-gate transistors. The semiconductor material used for the transistors is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and gallium nitride. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In—Ga—Zn-based metal oxide, may be used.

[0248] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0249] Here, it is preferable to use an oxide semiconductor for the transistors provided in the pixel and the driver circuit, as well as for semiconductor devices such as transistors used in touch sensors, which will be described later. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0250] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn-based oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0251] In particular, it is preferable to use, as the semiconductor layer, an oxide semiconductor film which has a plurality of crystal parts whose c-axes are oriented perpendicular to the surface on which the semiconductor layer is formed or the top surface of the semiconductor layer and in which no grain boundary can be found between adjacent crystal parts.

[0252] By using such a material for the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0253] Furthermore, a transistor having the above-described semiconductor layer can retain charge accumulated in a capacitor through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop a driver circuit while maintaining the gray level of each pixel. As a result, an electronic device with extremely low power consumption can be realized.

[0254] For example, to stabilize the characteristics of a transistor, it is preferable to provide a base film. The base film can be formed as a single layer or a stacked layer using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The base film can be formed by a sputtering method, a CVD (Chemical Vapor Deposition) method (such as a plasma CVD method, a thermal CVD method, or a MOCVD (Metal Organic CVD) method), an ALD (Atomic Layer Deposition) method, a coating method, a printing method, or the like. Note that the base film need not be provided if it is not necessary.

[0255] Note that the FET 623 represents one of the transistors formed in the source line driver circuit 601. The driver circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In addition, although this embodiment shows a driver-integrated type in which the driver circuit is formed on a substrate, this is not necessarily required, and the driver circuit may also be formed externally rather than on the substrate.

[0256] Furthermore, the pixel portion 602 is formed by a plurality of pixels including a switching FET 611, a current control FET 612, and a first electrode 613 electrically connected to the drain of the FET, but is not limited to this, and the pixel portion may be formed by combining three or more FETs and a capacitance element.

[0257] An insulator 614 is formed to cover an end portion of the first electrode 613. Here, the insulator 614 can be formed by using a positive photosensitive acrylic resin film.

[0258] Furthermore, in order to improve the coverage of organic compound layers and the like to be formed later, a curved surface having a curvature is formed at the upper or lower end of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material for the insulator 614, it is preferable to provide a curved surface having a curvature radius (0.2 μm to 3 μm) only at the upper end of the insulator 614. Furthermore, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0259] An organic compound layer 616 and a second electrode 617 are formed on the first electrode 613. Here, it is desirable to use a material with a large work function as the material used for the first electrode 613, which functions as an anode. For example, a single layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt % zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film can be used. It is also possible to use a stacked structure of a titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film. The stacked structure provides low resistance as a wiring, good ohmic contact, and the first electrode 613 can further function as an anode.

[0260] The organic compound layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an ink-jet method, or a spin coating method. The organic compound layer 616 includes the structure described in Embodiment 1. Other materials constituting the organic compound layer 616 may be low-molecular-weight compounds or high-molecular-weight compounds (including oligomers and dendrimers).

[0261] Furthermore, as a material used for the second electrode 617 formed on the organic compound layer 616 and functioning as a cathode, a material having a small work function (Al, Mg, Li, Ca, or alloys and compounds thereof (MgAg, MgIn, AlLi, etc.)) is preferably used. Note that, when light generated in the organic compound layer 616 is transmitted through the second electrode 617, it is preferable to use a stack of a thin metal thin film and a transparent conductive film (ITO, indium oxide containing 2 to 20 wt % zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) as the second electrode 617.

[0262] Note that a light-emitting device is formed with the first electrode 613, the organic compound layer 616, and the second electrode 617. The light-emitting device is the light-emitting device described in Embodiment 1. Note that a pixel portion is formed with a plurality of light-emitting devices, but the display device in this embodiment may include both the light-emitting device described in Embodiment 1 and light-emitting devices having other structures.

[0263] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealing material 605, a structure is formed in which a light-emitting device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The space 607 is filled with a filler, and in some cases, the space is filled with an inert gas (nitrogen, argon, etc.), or with a sealing material. A recess is formed in the sealing substrate, and by providing a desiccant therein, deterioration due to the influence of moisture can be suppressed, which is a preferable configuration.

[0264] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as moisture and oxygen impermeable as possible. In addition, materials that can be used for the sealing substrate 604 include glass substrates, quartz substrates, and plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, etc.

[0265] Although not shown in Fig. 5, a protective film may be provided on the second electrode. The protective film may be formed of an organic resin film or an inorganic insulating film. The protective film may also be formed so as to cover the exposed portion of the sealing material 605. The protective film may also be provided so as to cover the surfaces and side surfaces of the pair of substrates, the exposed side surfaces of the sealing layer, the insulating layer, etc.

[0266] The protective film can be made of a material that is impermeable to impurities such as water, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0267] The protective film may be made of an oxide, nitride, fluoride, sulfide, ternary compound, metal, polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, or the like; a nitride containing titanium and aluminum, an oxide containing titanium and aluminum, an oxide containing aluminum and zinc, a sulfide containing manganese and zinc, a sulfide containing cerium and strontium, an oxide containing erbium and aluminum, or an oxide containing yttrium and zirconium, or the like.

[0268] The protective film is preferably formed using a film formation method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using ALD for the protective film. By using ALD, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. In addition, it is possible to reduce damage to the workpiece when forming the protective film.

[0269] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on surfaces having complex uneven shapes, as well as on the top, side, and back surfaces of a touch panel.

[0270] In this manner, a display device manufactured using the light-emitting device described in Embodiment Mode 1 can be obtained.

[0271] The display device in this embodiment mode uses the light-emitting device described in Embodiment 1, and therefore, a display device with favorable characteristics can be obtained. Specifically, the light-emitting device described in Embodiment 1 has high emission efficiency, and therefore, a display device with low power consumption can be obtained. Furthermore, the light-emitting device described in Embodiment 1 has favorable reliability, and therefore, a display device with favorable reliability can be obtained. In addition, the light-emitting device described in Embodiment 1 can be a light-emitting device with favorable chromaticity and color purity, and therefore, a display device with favorable display quality can be obtained.

[0272] This embodiment mode can be freely combined with other embodiment modes.

[0273] 6A and 6B, a display device is formed in which a plurality of light-emitting devices 130 are formed over an insulating layer 175. In this embodiment, a display device according to one embodiment of the present invention will be described in detail.

[0274] The display device 100 has a pixel section 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.

[0275] 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 the subpixels 110. When describing matters common to other components distinguished by alphabets, they may also be described using symbols without the alphabets.

[0276] 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 unit 177. Note that in this 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 also be used. The number of sub-pixels is not limited to three, and may be four or more. Examples of 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 light (IR).

[0277] In this specification, 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.

[0278] 6A 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 also be arranged side by side in the Y direction, and subpixels of the same color may also be arranged side by side in the X direction.

[0279] 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 organic compound layer 103 is provided in the region 141. In addition, the connection portion 140 is provided with a conductive layer 151C.

[0280] 6 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.

[0281] Fig. 6B is an example of a cross-sectional view taken along dashed line A1-A2 in Fig. 6A. As shown in Fig. 6A, display device 100 has insulating layer 171, conductive layer 172 on insulating layer 171, insulating layer 173 on insulating layer 171 and on conductive layer 172, insulating layer 174 on insulating layer 173, and insulating layer 175 on insulating layer 174. Insulating layer 171 is provided on a substrate (not shown). Insulating layer 175, insulating layer 174, and insulating layer 173 have openings that reach conductive layer 172, and plugs 176 are provided to fill the openings.

[0282] 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 to cover the light-emitting device 130. The substrate 120 is bonded to the protective layer 131 by a resin layer 122. Preferably, an inorganic insulating layer 125 and an insulating layer 127 on the inorganic insulating layer 125 are provided between adjacent light-emitting devices 130.

[0283] 6B shows multiple cross sections of inorganic insulating layer 125 and insulating layer 127, it is preferable that inorganic insulating layer 125 and insulating layer 127 are connected to each other as a single layer when display device 100 is viewed from above. In other words, it is preferable that insulating layer 127 is an insulating layer having an opening above the first electrode.

[0284] 6B shows light-emitting device 130 as light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B. Light-emitting device 130R, light-emitting device 130G, and light-emitting device 130B emit light of different colors. For example, light-emitting device 130R can emit red light, light-emitting device 130G can emit green light, and light-emitting device 130B can emit blue light. Light-emitting device 130R, light-emitting device 130G, or light-emitting device 130B may also emit other visible light or infrared light.

[0285] The display device of one embodiment of the present invention can be, for example, a top-emission type in which light is emitted 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 also be a bottom-emission type.

[0286] Examples of the light-emitting material contained in the light-emitting device 130 include organic compounds or organometallic complexes such as fluorescent materials, phosphorescent materials, and thermally activated delayed fluorescence (TADF) materials. The light-emitting material may also be an inorganic compound such as quantum dots.

[0287] The light-emitting device 130R has the structure described in Embodiment 1. It includes a first electrode (pixel electrode) composed of a conductive layer 151R and a conductive layer 152R, an organic compound layer 103R on the first electrode, a common layer 104 on the organic compound layer 103R, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but is preferably provided because it can reduce damage to the organic compound layer 103R during processing. When the common layer 104 is provided, it is preferably an electron injection layer. When the common layer 104 is provided, the stacked structure of the organic compound layer 103R and the common layer 104 corresponds to the organic compound layer 103.

[0288] The light-emitting device 130G has the structure described in Embodiment 1. It includes a first electrode (pixel electrode) including a conductive layer 151G and a conductive layer 152G, an organic compound layer 103G on the first electrode, a common layer 104 on the organic compound layer 103G, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but is preferably provided because it can reduce damage to the organic compound layer 103G during processing. When the common layer 104 is provided, it is preferably an electron injection layer. When the common layer 104 is provided, the stacked structure of the organic compound layer 103G and the common layer 104 corresponds to the organic compound layer 103.

[0289] The light-emitting device 130B has the structure described in Embodiment 1. It includes a first electrode (pixel electrode) including a conductive layer 151B and a conductive layer 152B, an organic compound layer 103B on the first electrode, a common layer 104 on the organic compound layer 103B, and a second electrode (common electrode) 102 on the common layer. The common layer 104 may or may not be provided, but is preferably provided because it can reduce damage to the organic compound layer 103B during processing. When the common layer 104 is provided, it is preferably an electron injection layer. When the common layer 104 is provided, the stacked structure of the organic compound layer 103B and the common layer 104 corresponds to the organic compound layer 103.

[0290] One of the pixel electrode and the common electrode of the light-emitting device functions as an anode and the other functions as a cathode. In the following description, unless otherwise specified, the pixel electrode functions as an anode and the common electrode functions as a cathode.

[0291] The organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B are independent and island-shaped for each light-emitting device. By providing the organic compound layer 103 in an island shape for each light-emitting device 130, leakage current between adjacent light-emitting devices 130 can be suppressed even in a high-resolution display device. This makes it possible to prevent crosstalk and realize a display device with extremely high contrast. In particular, a display device with high current efficiency at low brightness can be realized.

[0292] The island-shaped organic compound layer 103 is formed by depositing an EL film and processing the EL film using a lithography method.

[0293] In addition, in the display device of one embodiment of the present invention, the first electrode (pixel electrode) of the light-emitting device preferably has a stacked structure. For example, in the example shown in FIG. 6B , the first electrode of the light-emitting device 130 has a stacked structure of a conductive layer 151 (conductive layer 151R, conductive layer 151G, and conductive layer 151B) and a conductive layer 152 (conductive layer 152R, conductive layer 152G, and conductive layer 152B). For example, when the display device 100 is a top-emission type and the pixel electrode of the light-emitting device 130 functions as an anode, it is preferable that the conductive layer 151 has high reflectivity for visible light, and the conductive layer 152 has transparency to visible light and a high work function. In the case where the display device 100 is a top-emission type, the higher the reflectivity of the pixel electrode for visible light, the higher the extraction efficiency of light emitted from the organic compound layer 103. In addition, when the pixel electrode functions as an anode, the higher the work function of the pixel electrode, the easier it is to inject holes into the organic compound layer 103. As described above, by forming the pixel electrode of the light-emitting device 130 into a stacked structure of the conductive layer 151 having a high reflectivity for visible light and the conductive layer 152 having a high work function, the light-emitting device 130 can be made into a light-emitting device with high light extraction efficiency and low driving voltage.

[0294] When the conductive layer 151 is a layer having high reflectivity to visible light, the reflectivity of the conductive layer 151 to visible light is preferably, for example, 40% to 100%, or 70% to 100%. When the conductive layer 152 is an electrode that is transparent to visible light, the transmittance of the conductive layer 152 to visible light is preferably, for example, 40% or more.

[0295] 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), and neodymium (Nd), as well as alloys containing appropriate combinations of these metals, can also be used.

[0296] An oxide containing one or more selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used for the conductive layer 152. 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.

[0297] The conductive layer 151 or the conductive layer 152 may have a stacked structure of multiple layers containing different materials. In this case, the conductive layer 151 may include a layer using a material that can be used for the conductive layer 152, such as a conductive oxide, or the conductive layer 152 may include a layer using a material that can be used for the conductive layer 151, such as a metal material. For example, when the conductive layer 151 has a stacked structure of two or more layers, 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.

[0298] Note that the side surfaces of the conductive layer 151 or the conductive layer 152 preferably have a tapered shape. Specifically, the side surfaces of the conductive layer 151 or the conductive layer 152 preferably have a tapered shape with a taper angle of less than 90°. The end surfaces of the insulating layer 156 (the insulating layer 156R, the insulating layer 156G, and the insulating layer 156B) may also have a tapered shape. Specifically, when the end surfaces of the insulating layer 156 have a tapered shape with a taper angle of less than 90°, the coverage of structures provided along the side surfaces of the insulating layer 156 can be improved.

[0299] The conductive layer 151 may also have a stacked structure of three or more layers. When the conductive layer 151 has a stacked structure of multiple layers, the reflectivity of at least one of the layers constituting the conductive layer 151 to visible light may be higher than the reflectivity of the conductive layer 152 to visible light. When the conductive layer 151 has a structure of three or more layers, it is preferable that the outermost conductive layer be made of a material that is less susceptible to deterioration than the conductive layers used in the middle. For example, a material that is less likely to cause migration than materials used in other layers can be used for the layer in contact with the insulating layer 175. A material that is less susceptible to oxidation and has an oxide with lower electrical resistivity than the oxides of materials used in other layers can be used for the layer in contact with the insulating layer 175.

[0300] As described above, the range of materials that can be selected for the conductive layer 151 can be widened. Therefore, by using aluminum or an alloy containing aluminum as the material for the conductive layer 151, the layer can have high reflectivity for visible light. Furthermore, aluminum may be combined with titanium, which has a lower reflectivity for visible light than aluminum but is less likely to cause migration than aluminum even when in contact with the insulating layer 175.

[0301] Alternatively, silver or an alloy containing silver may be used for the conductive layer 151. Silver has a characteristic that its reflectivity to visible light is higher than that of titanium. Furthermore, silver is less susceptible to oxidation than aluminum, and the electrical resistivity of silver oxide is lower than that of aluminum oxide. As described above, when silver or an alloy containing silver is used for the conductive layer 151, the reflectivity of the conductive layer 151 to visible light can be suitably increased while suppressing an increase in the electrical resistance of the pixel electrode due to oxidation. Here, an alloy containing silver can be, for example, an alloy of silver, palladium, and copper (Ag-Pd-Cu, also referred to as APC).

[0302] For example, when a microcavity structure is applied to the light-emitting device 130, the conductive layer 151 can be made of silver, which is a material with high reflectivity for visible light, or an alloy containing silver, to suitably increase the light extraction efficiency of the display device 100.

[0303] Furthermore, when the conductive layer 152 has a layered structure, by making the layered structure have different reflectivities for visible light (for example, reflectivities for light of a predetermined wavelength in the range of 400 nm or more and less than 750 nm), it is possible to form a microcavity structure in combination with the conductive layer 151.

[0304] As described above, the characteristics of the display device can be improved by forming the conductive layer 151 or the conductive layer 152 into a stacked structure of multiple layers. For example, the display device 100 can have high light extraction efficiency and high reliability.

[0305] The conductive layer 151 can be formed by lithography. Specifically, first, a conductive film that will become the conductive layer 151 is formed. Next, a resist mask is formed on the conductive film that will become the conductive layer 152. After that, the conductive film in a region that does not overlap with the resist mask is removed by, for example, etching. Here, compared to when the conductive layer 151 is formed so that the side surfaces do not have a tapered shape, that is, so that the side surfaces are vertical, the conductive film is processed under conditions that make it easy for the resist mask to recede (shrink). This makes it possible to form the side surfaces of the conductive layer 151 into a tapered shape.

[0306] The conductive layer 152 may be processed by lithography simultaneously with the conductive layer 151. In this case, the side surface of the conductive layer 152 can also be formed into a tapered shape.

[0307] Here, if the conductive film is processed under conditions that make it easy for the resist mask to recede (shrink), the conductive film may be easily processed in the horizontal direction, which may result in higher isotropy of etching than when the conductive layer 151 is formed so that the side surfaces are vertical.

[0308] Furthermore, when the conductive layer 151 has a stacked structure of a plurality of layers made of different materials, the ease of processing in the horizontal direction may differ between the plurality of layers.

[0309] 6B , the insulating layer 156 can prevent corrosion of the conductive layer 151. Therefore, the display device 100 can be manufactured with a high yield. Furthermore, the occurrence of defects can be prevented, and the display device 100 can be a highly reliable display device.

[0310] As shown in FIG. 6B , the insulating layer 156 preferably has a curved surface. This can reduce the occurrence of discontinuities in the conductive layer 152 covering the insulating layer 156, compared to when the side surfaces of the insulating layer 156 are vertical (parallel to the Z direction). Even when the insulating layer 156 has a tapered shape on the side surface, specifically a tapered shape with a taper angle of less than 90°, the occurrence of discontinuities in the conductive layer 152 covering the insulating layer 156 can be reduced, compared to when the side surfaces of the insulating layer 156 are vertical. As described above, the display device 100 can be manufactured using a method with a high yield. Furthermore, the occurrence of defects is reduced, making the display device 100 a highly reliable display device.

[0311] 6A , an example of a manufacturing method for the display device 100 will be described with reference to FIGS. 7 to 12. The light-emitting device included in the display device 100 has an organic layer formed by a manufacturing process including a treatment using water. By using the organic compound of one embodiment of the present invention for the organic layer of the light-emitting device included in the display device of one embodiment of the present invention, even when the display device is manufactured by a manufacturing method including a treatment using water, problems such as dissolution of the layer including the organic compound and penetration of a chemical solution into the layer including the organic compound can be prevented, and a light-emitting device with excellent characteristics can be provided.

[0312] The display device 100 may be fabricated using a fabrication method (a so-called integrated vacuum process) that does not involve a process of exposing the display device to the atmosphere or a process of processing an organic compound layer using photolithography. A light-emitting device fabricated using an integrated vacuum process can provide a light-emitting device with good characteristics because the substrate is not contaminated during the fabrication process.

[0313] [Example of Manufacturing Method] Thin films (insulating films, semiconductor films, conductive films, etc.) constituting the display device can be formed using a sputtering method, a chemical vapor deposition (CVD) method, a vacuum evaporation method, a pulsed laser deposition (PLD) method, an ALD method, etc. CVD methods include a plasma enhanced chemical vapor deposition (PECVD) method and a thermal CVD method. One type of thermal CVD method is a metal organic chemical vapor deposition (MOCVD) method.

[0314] Furthermore, 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.

[0315] In particular, vacuum processes such as vapor deposition and solution processes such as spin coating and inkjet printing can be used to fabricate light-emitting devices. Vapor deposition methods include physical vapor deposition (PVD) methods such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, and chemical vapor deposition (CVD). In particular, functional layers (hole injection layer, hole transport layer, hole blocking layer, light-emitting layer, electron blocking layer, electron transport layer, electron injection layer, etc.) included in the organic compound layer can be formed by vapor deposition (vacuum deposition, etc.), coating methods (dip coating, die coating, bar coating, spin coating, spray coating, etc.), printing methods (inkjet printing, screen (stencil printing), offset (lithographic printing), flexography (relief printing), gravure, microcontact printing, etc.), etc.

[0316] Furthermore, when processing the thin film that constitutes the display device, it can be processed using, for example, a lithography method. Alternatively, the thin film may be processed using a nanoimprint method, a sandblasting method, a lift-off method, etc. Furthermore, the island-shaped thin film may be directly formed by a film formation method using a shielding mask such as a metal mask.

[0317] As a lithography method, for example, photolithography can be used. There are two typical photolithography methods: one is a method in which a resist mask is formed on a thin film to be processed, the thin film is processed by, for example, etching, and then the resist mask is removed; and the other is a method in which a photosensitive thin film is formed, and then the thin film is exposed to light and developed to be processed into a desired shape.

[0318] In photolithography, 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. Other light sources that can be used include ultraviolet light, KrF laser light, ArF laser light, etc. 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. Extreme ultraviolet light, X-rays, or an electron beam are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0319] The thin film can be etched by dry etching, wet etching, sandblasting, or the like.

[0320] 7A , an insulating layer 171 is formed on a substrate (not shown). Subsequently, conductive layers 172 and 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 layers 172 and 179. Subsequently, an insulating layer 174 is formed on the insulating layer 173, and an insulating layer 175 is formed on the insulating layer 174.

[0321] The substrate may be a substrate having heat resistance sufficient to withstand at least a subsequent heat treatment. When an insulating substrate is used, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like may be used. Also, a semiconductor substrate such as a single crystal semiconductor substrate made of silicon or silicon carbide, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or an SOI (Silicon on Insulator) substrate may be used.

[0322] 7A, openings are formed in the insulating layers 175, 174, and 173, reaching the conductive layer 172. Then, plugs 176 are formed to fill the openings.

[0323] 7A , a conductive film 151f, which will later become the conductive layers 151R, 151G, 151B, and 151C, is formed on the plug 176 and the insulating layer 175. The conductive film 151f can be formed by, for example, sputtering or vacuum deposition. The conductive film 151f can be made of, for example, a metal material.

[0324] 7A , a conductive film 152f, which will later become the conductive layers 152R, 152G, 152B, and 152C, is formed over the conductive film 151f. The conductive film 152f can be formed by, for example, sputtering or vacuum evaporation. Alternatively, the conductive film 152f can be formed using, for example, a conductive oxide. Alternatively, the conductive film 152f can have a stacked structure of a film using a metal material and a film using a conductive oxide on the metal material. For example, the conductive film 152f can have a stacked structure of a film using titanium, silver, or an alloy containing silver and a film using a conductive oxide on the metal material.

[0325] The conductive film 152f can be formed by an ALD method. In this case, an oxide containing one or more elements selected from indium, tin, zinc, gallium, titanium, aluminum, and silicon can be used as the conductive film 152f. In this case, the conductive film 152f can be formed by repeating a cycle consisting of introducing a precursor (which may be generally referred to as a precursor or a metal precursor), purging the precursor, introducing an oxidizing agent (which may be generally referred to as a reactant, a non-metal precursor, or the like), and purging the oxidizing agent. When an oxide film containing multiple metals, such as indium tin oxide, is formed as the conductive film 152f, the metal composition can be controlled by varying the number of cycles for each type of precursor.

[0326] For example, when forming an indium tin oxide film as the conductive film 152f, an indium-containing precursor is introduced, the precursor is purged, an oxidizing agent is introduced, and an In—O film is formed. Next, a tin-containing precursor is introduced, the precursor is purged, and an oxidizing agent is introduced, and an Sn—O film is formed. Here, by making the number of cycles for forming the In—O film larger than the number of cycles for forming the Sn—O film, the number of In atoms contained in the conductive film 152f can be made larger than the number of Sn atoms.

[0327] Furthermore, for example, when a zinc oxide film is formed as the conductive film 152f, a Zn—O film is formed using the above procedure. For example, when an aluminum zinc oxide film is formed as the conductive film 152f, a Zn—O film and an Al—O film are formed using the above procedure. For example, when a titanium oxide film is formed as the conductive film 152f, a Ti—O film is formed using the above procedure. For example, when an indium tin oxide film containing silicon is formed as the conductive film 152f, an In—O film, an Sn—O film, and an Si—O film are formed using the above procedure. For example, when a zinc oxide film containing gallium is formed, a Ga—O film and a Zn—O film are formed using the above procedure.

[0328] Examples of indium-containing precursors include triethylindium, trimethylindium, and [1,1,1-trimethyl-N-(trimethylsilyl)amido]-indium. Examples of tin-containing precursors include tin chloride and tetrakis(dimethylamido)tin. Examples of zinc-containing precursors include diethylzinc and dimethylzinc. Examples of gallium-containing precursors include triethylgallium. Examples of titanium-containing precursors include titanium chloride, tetrakis(dimethylamido)titanium, and tetraisopropyl titanate. Examples of aluminum-containing precursors include aluminum chloride and trimethylaluminum. Examples of silicon-containing precursors include trisilylamine, bis(diethylamino)silane, tris(dimethylamino)silane, bis(tert-butylamino)silane, and bis(ethylmethylamino)silane. Examples of oxidizing agents include water vapor, oxygen plasma, and ozone gas.

[0329] 7A, a resist mask 191 is formed over the conductive film 151f and the conductive film 152f. The resist mask 191 can be formed by applying a photosensitive material (photoresist) and then performing exposure and development.

[0330] 7B , for example, the conductive films 151f and 152f in regions that do not overlap with the resist mask 191 are removed by, for example, etching, specifically, dry etching, to form a pixel electrode including the conductive layer 151 and the conductive layer 152. Note that if the conductive film 151f includes a layer using a conductive oxide such as indium tin oxide, the layer may be removed by wet etching. As a result, the conductive layer 151 and the conductive layer 152 are formed. Note that, for example, when a portion of the conductive film 151f is removed by dry etching, a recess may be formed in a region of the insulating layer 175 that does not overlap with the conductive layer 151.

[0331] Note that the conductive film 152f may be processed by lithography to form the conductive layers 152R, 152G, 152B, and 152C, and then the conductive film 151f may be processed using the conductive layers 152R, 152G, 152B, and 152C as masks. Specifically, for example, after forming a resist mask, part of the conductive film 152f is removed by etching. The conductive film 152f can be removed by, for example, wet etching. The conductive film 152f may also be removed by dry etching. Then, the conductive film 151f may be removed by wet etching.

[0332] Here, it is preferable to perform hydrophobic treatment on the conductive layer 152. The hydrophobic treatment can change the surface to be treated from hydrophilic to hydrophobic, or can increase the hydrophobicity of the surface to be treated. By performing the hydrophobic treatment on the conductive layer 152, adhesion between the conductive layer 152 and the organic compound layer 103 formed in a later step can be increased, and film peeling can be suppressed. Note that the hydrophobic treatment is not necessarily performed.

[0333] 7C, the resist mask 191 is removed. The resist mask 191 can be removed by ashing using oxygen plasma, or by ashing using oxygen gas and CF ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ Alternatively, a Group 18 element such as He may be used. Alternatively, the resist mask 191 may be removed by wet etching.

[0334] 7D , an insulating film 156f, which will later become insulating layers 156R, 156G, 156B, and 156C, is formed on the conductive layers 151R and 152R, 151G and 152G, 151B and 152B, 151C and 152C, and on the insulating layer 175. The insulating film 156f can be formed by, for example, CVD, ALD, sputtering, or vacuum deposition.

[0335] The insulating film 156f can be formed using an inorganic material. For example, the insulating film 156f can be formed using an inorganic insulating film such as an oxide insulating film, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. For example, the insulating film 156f can be formed using an oxide insulating film containing silicon, a nitride insulating film, an oxynitride insulating film, or a nitride oxide insulating film. For example, the insulating film 156f can be formed using silicon oxynitride.

[0336] 7E, the insulating film 156f is processed to form insulating layers 156R, 156G, 156B, and 156C. For example, the insulating layer 156 can be formed by uniformly etching the upper surface of the insulating film 156f. Such uniform etching and planarization is also called an etch-back process. The insulating layer 156 may also be formed using lithography.

[0337] Next, as shown in FIG. 8A, an organic compound film 103Rf, which will later become the organic compound layer 103R, is formed on the conductive layer 152R, the conductive layer 152G, the conductive layer 152B, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, and the insulating layer 175.

[0338] 8A , the organic compound film 103Rf is not formed on the conductive layer 152C. For example, by using a mask for defining the film formation area (also called an area mask or a rough metal mask to distinguish it from a fine metal mask), the organic compound film 103Rf can be formed only in the desired region. By employing a film formation process using an area mask and a processing process using a resist mask, the light-emitting device can be manufactured through a relatively simple process.

[0339] The organic compound film 103Rf can be formed by, for example, a vapor deposition method, specifically a vacuum deposition method. Alternatively, the organic compound film 103Rf may be formed by a transfer method, a printing method, an inkjet method, a coating method, or the like.

[0340] Subsequently, as shown in FIG. 8A, a sacrificial film 158Rf, which will later become the sacrificial layer 158R, and a mask film 159Rf, which will later become the mask layer 159R, are formed in this order on the organic compound film 103Rf, the conductive layer 152C, and the insulating layer 175.

[0341] In this embodiment, an example is shown in which the mask film is formed with a two-layer structure of the sacrificial film 158Rf and the mask film 159Rf, but the mask film may have a single-layer structure or a laminated structure of three or more layers.

[0342] By providing a sacrificial layer on the organic compound film 103Rf, damage to the organic compound film 103Rf during the manufacturing process of the display device can be reduced, and the reliability of the light-emitting device can be improved.

[0343] The sacrificial film 158Rf is made of a film that is highly resistant to the processing conditions of the organic compound film 103Rf, specifically, a film that has a large etching selectivity with respect to the organic compound film 103Rf.The mask film 159Rf is made of a film that has a large etching selectivity with respect to the sacrificial film 158Rf.

[0344] 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 200° C. or lower, preferably 150° C. or lower, more preferably 120° C. or lower, more preferably 100° C. or lower, and even more preferably 80° C. or lower.

[0345] The sacrificial film 158Rf and the mask film 159Rf are preferably made of films that can be removed by wet etching, which can reduce damage to the organic compound film 103Rf when processing the sacrificial film 158Rf and the mask film 159Rf compared to when dry etching is used.

[0346] The sacrificial film 158Rf and the mask film 159Rf can be formed by, for example, sputtering, ALD (thermal ALD, PEALD), CVD, or vacuum deposition. Alternatively, they may be formed by the wet film formation method described above.

[0347] 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, it is preferable to form the sacrificial film 158Rf using the ALD method or the vacuum deposition method rather than the sputtering method.

[0348] 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, an inorganic insulating film, or the like.

[0349] The sacrificial film 158Rf and the mask film 159Rf can be made of 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 such a metal material. It is particularly preferable to use a low-melting-point material such as aluminum or silver. Using a metal material capable of blocking ultraviolet rays for one or both of the sacrificial film 158Rf and the mask film 159Rf is preferable because it can prevent ultraviolet rays from being irradiated onto the organic compound film 103Rf and suppress deterioration of the organic compound film 103Rf.

[0350] 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.

[0351] In addition, instead of the above gallium, 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.

[0352] Furthermore, it is preferable to use a film containing a material that has light-shielding properties against light, particularly ultraviolet light, as the sacrificial film and the mask film. As the light-shielding material, various materials such as metals, insulators, semiconductors, and semimetals that have light-shielding properties against ultraviolet light can be used, but since part or all of the sacrificial film and the mask film will be removed in a later step, it is preferable that the film be a film that can be processed by etching, and it is particularly preferable that the film have good processability.

[0353] As the sacrificial film and mask film, for example, semiconductor materials such as silicon or germanium are preferred because they have high compatibility with semiconductor manufacturing processes. Alternatively, oxides or nitrides of the above semiconductor materials can be used. Alternatively, non-metallic materials such as carbon or their compounds can be used. Alternatively, metals such as titanium, tantalum, tungsten, chromium, and aluminum, or alloys containing one or more of these, can be used. Alternatively, oxides containing the above metals such as titanium oxide or chromium oxide, or nitrides such as titanium nitride, chromium nitride, or tantalum nitride can be used.

[0354] By using a film containing a material that blocks ultraviolet light for the sacrificial film and the mask film, it is possible to prevent the organic compound layer from being irradiated with ultraviolet light during, for example, an exposure process, and by preventing the organic compound layer from being damaged by ultraviolet light, the reliability of the light-emitting device can be improved.

[0355] The same effect can be achieved when a film containing a material that blocks ultraviolet light is used as the material for the inorganic insulating film 125f, which will be described later.

[0356] Furthermore, various inorganic insulating films can be used for the sacrificial film 158Rf and the mask film 159Rf. In particular, oxide insulating films are preferable because they have higher adhesion to the organic compound film 103Rf than nitride insulating films. For example, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used for the sacrificial film 158Rf and the mask film 159Rf. For example, aluminum oxide films can be formed as the sacrificial film 158Rf and the mask film 159Rf using the ALD method. Using the ALD method is preferable because it reduces damage to the underlying layer (especially the organic compound layer).

[0357] For example, the sacrificial film 158Rf can be an inorganic insulating film (e.g., an aluminum oxide film) formed using the ALD method, and the mask film 159Rf can be an inorganic film (e.g., an In—Ga—Zn oxide film, an aluminum film, or a tungsten film) formed using the sputtering method.

[0358] The same inorganic insulating film can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125 to be formed later. For example, an aluminum oxide film formed using an ALD method can be used for both the sacrificial film 158Rf and the inorganic insulating layer 125. The same or different film-forming conditions can be applied to the sacrificial film 158Rf and the inorganic insulating layer 125. For example, by forming the sacrificial film 158Rf under the same conditions as the inorganic insulating layer 125, the sacrificial film 158Rf can be an insulating layer with high barrier properties against at least one of water and oxygen. On the other hand, since the sacrificial film 158Rf is a layer that will be mostly or completely removed in a later process, it is preferable that it be easily processed. For this reason, the sacrificial film 158Rf is preferably formed under conditions where the substrate temperature during film formation is lower than that of the inorganic insulating layer 125.

[0359] An organic material may be used for one or both of the sacrificial film 158Rf and the mask film 159Rf. For example, the organic material may be a material that is soluble in a solvent that is chemically stable with respect to at least the film located at the top of the organic compound film 103Rf. In particular, a material that dissolves in water or alcohol is preferably used. When forming a film of such a material, it is preferable to apply the material dissolved in a solvent such as water or alcohol by a wet film formation method, and then perform a heat treatment to evaporate the solvent. In this case, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to the organic compound film 103Rf.

[0360] The sacrificial film 158Rf and the mask film 159Rf may each be made of an organic resin such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, alcohol-soluble polyamide resin, or a fluororesin such as a perfluoropolymer.

[0361] For example, the sacrificial film 158Rf can be an organic film (e.g., a PVA film) formed using either a vapor deposition method or the above-mentioned wet film formation method, and the mask film 159Rf can be an inorganic film (e.g., a silicon nitride film) formed using a sputtering method.

[0362] 8A, a resist mask 190R is formed on the mask film 159Rf. The resist mask 190R can be formed by applying a photosensitive material (photoresist) and then performing exposure and development.

[0363] The resist mask 190R may be made of either a positive resist material or a negative resist material.

[0364] The resist mask 190R is provided in a position overlapping with the conductive layer 152R. The resist mask 190R is preferably also provided in a position overlapping with the conductive layer 152C. This can prevent the conductive layer 152C from being damaged during the manufacturing process of the display device. Note that the resist mask 190R does not necessarily have to be provided on the conductive layer 152C. Furthermore, as shown in the cross-sectional view between B1 and B2 in FIG. 8A , the resist mask 190R is preferably provided so as to cover from the end of the organic compound film 103Rf to the end of the conductive layer 152C (the end on the organic compound film 103Rf side).

[0365] 8B , 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 then used as a mask (also referred to as a hard mask) to remove a portion of the sacrificial film 158Rf to form a sacrificial layer 158R.

[0366] The sacrificial film 158Rf and the mask film 159Rf can be processed by wet etching or dry etching, respectively, and are preferably processed by isotropic etching.

[0367] 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 when using the dry etching method. When using the wet etching method, it is preferable to use a chemical solution using, for example, a developer, a tetramethylammonium hydroxide aqueous solution (TMAH), dilute hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture thereof.

[0368] In processing the mask film 159Rf, the organic compound film 103Rf is not exposed, and therefore the range of processing method options is wider than in processing the sacrificial film 158Rf. Specifically, even when a gas containing oxygen is used as an etching gas in processing the mask film 159Rf, deterioration of the organic compound film 103Rf can be further suppressed.

[0369] Furthermore, when dry etching is used to process the sacrificial film 158Rf, deterioration of the organic compound film 103Rf can be suppressed by not using a gas containing oxygen as the etching gas. ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３ It is preferable to use a gas containing a Group 18 element such as He or the like as the etching gas.

[0370] For example, when an aluminum oxide film formed by the ALD method is used as the sacrificial film 158Rf, CHF ３ and He or CHF ３ and He and CH ４ In addition, when an In—Ga—Zn oxide film formed by sputtering is used as the mask film 159Rf, the mask film 159Rf can be partially removed by wet etching using diluted phosphoric acid. ４ A part of the mask film 159Rf may be removed by dry etching using Ar. Alternatively, a part of the mask film 159Rf may be removed by wet etching using diluted phosphoric acid. In addition, when a tungsten film formed by sputtering is used as the mask film 159Rf, SF ６ , C.F. ４ and O ２ , or CF ４ and Cl ２ and O ２ Using this, a part of the mask film 159Rf can be removed by dry etching.

[0371] The resist mask 190R can be removed in the same manner as the resist mask 191. For example, it can be removed by ashing using oxygen plasma. Alternatively, it can be removed by ashing using oxygen gas and CF ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H２ O, BCl ３ Alternatively, a Group 18 element such as He or the like may be used. Alternatively, the resist mask 190R may be removed by wet etching. At this time, the sacrificial film 158Rf is located on the outermost surface and the organic compound film 103Rf is not exposed, so that damage to the organic compound film 103Rf can be suppressed in the process of removing the resist mask 190R. Furthermore, the range of options for removing the resist mask 190R can be expanded.

[0372] 8B, 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 portion of the organic compound film 103Rf, thereby forming the organic compound layer 103R.

[0373] 8B, a laminated structure of the organic compound layer 103R, the sacrificial layer 158R, and the mask layer 159R remains on the conductive layer 152R, and the conductive layers 152G and 152B are exposed.

[0374] 8B shows an example in which the edge of the organic compound layer 103R is located inside the edge of the conductive layer 152R. This structure enables miniaturization of pixels, enabling the manufacture of a high-resolution display. Note that, although not shown in FIG. 8B , the etching process may form a recess in a region of the insulating layer 175 that does not overlap with the organic compound layer 103R.

[0375] As described above, the resist mask 190R is preferably provided to cover the area between the dashed-dotted lines B1-B2 from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side). As a result, as shown in FIG. 8B , the sacrificial layer 158R and the mask layer 159R are provided to cover the area between the dashed-dotted lines B1-B2 from the end of the organic compound layer 103R to the end of the conductive layer 152C (the end on the organic compound layer 103R side). This prevents the insulating layer 175 from being exposed between the dashed-dotted lines B1-B2, for example. This prevents portions of the insulating layers 175, 174, and 173 from being removed by etching or the like, thereby preventing the conductive layer 179 from being exposed. This prevents the conductive layer 179 from being unintentionally electrically connected to other conductive layers. For example, this prevents a short circuit between the conductive layer 179 and the common electrode 155 formed in a later process.

[0376] The organic compound film 103Rf is preferably processed by anisotropic etching, particularly anisotropic dry etching, or wet etching may be used.

[0377] When dry etching is used, deterioration of the organic compound film 103Rf can be suppressed by not using a gas containing oxygen as the etching gas.

[0378] Alternatively, a gas containing oxygen may be used as the etching gas. By using an etching gas containing oxygen, the etching rate can be increased. Therefore, etching can be performed under low power conditions while maintaining a sufficiently high etching rate. 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.

[0379] When dry etching is used, for example, H ２ , C.F. ４ , C ４ F ８ , SF ６ , CHF ３ , Cl ２ , H ２ O, BCl ３It is preferable to use a gas containing one or more of Group 18 elements such as He, Ar, etc. as the etching gas. Alternatively, it is preferable to use a gas containing one or more of these elements and oxygen as the etching gas. Alternatively, oxygen gas may be used as the etching gas. Specifically, for example, H ２ and a gas containing Ar, or CF ４ A gas containing CF and He can be used as an etching gas. ４ A gas containing He and oxygen can be used as the etching gas. ２ A gas containing Ar and a gas containing oxygen can be used as the etching gas.

[0380] As described above, in one embodiment of the present invention, the resist mask 190R is formed over the mask film 159Rf, and part of the mask film 159Rf is removed using the resist mask 190R to form the mask layer 159R. Then, part of the organic compound film 103Rf is removed using the mask layer 159R as a hard mask to form the organic compound layer 103R. Therefore, it can be said that the organic compound layer 103R is formed by processing the organic compound film 103Rf using a lithography method. Note that part of the organic compound film 103Rf may be removed using the resist mask 190R. Then, the resist mask 190R may be removed.

[0381] Next, it is preferable to perform, for example, a hydrophobic treatment on the conductive layer 152G. During processing of the organic compound film 103Rf, for example, the surface state of the conductive layer 152G may change to a hydrophilic state. For example, by performing the hydrophobic treatment on the conductive layer 152G, it is possible to improve the adhesion between the conductive layer 152G and a layer (here, the organic compound layer 103G) formed in a later process, and to suppress film peeling. Note that the hydrophobic treatment is not necessarily required.

[0382] Next, as shown in FIG. 9A, an organic compound film 103Gf, which will later become the organic compound layer 103G, is formed on the conductive layer 152G, the conductive layer 152B, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159R, and the insulating layer 175.

[0383] The organic compound film 103Gf can be formed by the same method as that used to form the organic compound film 103Rf, and can have the same structure as the organic compound film 103Rf.

[0384] 9A , a sacrificial film 158Gf, which will later become the sacrificial layer 158G, and a mask film 159Gf, which will later become the mask layer 159G, are sequentially formed on the organic compound film 103Gf and the mask layer 159R. A resist mask 190G is then formed. The materials and formation methods for the sacrificial film 158Gf and the mask film 159Gf are the same as those applicable to the sacrificial film 158Rf and the mask film 159Rf. The materials and formation methods for the resist mask 190G are the same as those applicable to the resist mask 190R.

[0385] The resist mask 190G is provided in a position overlapping with the conductive layer 152G.

[0386] 9B , a resist mask 190G is used to remove a portion of the mask film 159Gf to form a mask layer 159G. The mask layer 159G remains on the conductive layer 152G. The resist mask 190G is then removed. The mask layer 159G is then used as a mask to remove a portion of the sacrificial film 158Gf to form a sacrificial layer 158G. The organic compound film 103Gf is then processed to form the organic compound layer 103G. For example, the mask layer 159G and the sacrificial layer 158G are used as hard masks to remove a portion of the organic compound film 103Gf to form the organic compound layer 103G.

[0387] 9B, a laminated structure of the organic compound layer 103G, the sacrificial layer 158G, and the mask layer 159G remains on the conductive layer 152G, and the mask layer 159R and the conductive layer 152B are exposed.

[0388] Next, it is preferable to perform, for example, a hydrophobic treatment on the conductive layer 152B. During processing of the organic compound film 103Gf, for example, the surface state of the conductive layer 152B may change to a hydrophilic state. For example, by performing the hydrophobic treatment on the conductive layer 152B, it is possible to increase the adhesion between the conductive layer 152B and a layer (here, the organic compound layer 103B) formed in a later process, and to suppress film peeling. Note that the hydrophobic treatment is not necessarily required.

[0389] Next, as shown in FIG. 9C , an organic compound film 103Bf, which will later become the organic compound layer 103B, is formed on the conductive layer 152B, the mask layer 159R, the insulating layer 156R, the insulating layer 156G, the insulating layer 156B, the mask layer 159G, and the insulating layer 175.

[0390] The organic compound film 103Bf can be formed by the same method as that used to form the organic compound film 103Rf, and can have the same structure as the organic compound film 103Rf.

[0391] 9C , a sacrificial film 158Bf, which will later become the sacrificial layer 158B, and a mask film 159Bf, which will later become the mask layer 159B, are sequentially formed on the organic compound film 103Bf and the mask layer 159R. A resist mask 190B is then formed. The materials and formation methods for 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 materials and formation methods for the resist mask 190B are the same as those applicable to the resist mask 190R.

[0392] The resist mask 190B is provided in a position overlapping with the conductive layer 152B.

[0393] 9D, 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 the 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.

[0394] 9D, a laminated structure of the organic compound layer 103B, the sacrificial layer 158B, and the mask layer 159B remains on the conductive layer 152B, and the mask layers 159R and 159G are exposed.

[0395] It is preferable that the side surfaces of the organic compound layers 103R, 103G, and 103B are perpendicular or substantially perpendicular to the surface on which they are formed. For example, it is preferable that the angle formed between the surface on which they are formed and these side surfaces be 60 degrees or more and 90 degrees or less.

[0396] As described above, the distance between adjacent pairs of the organic compound layers 103R, 103G, and 103B formed using lithography 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 the opposing ends of adjacent pairs of the organic compound layers 103R, 103G, and 103B. By narrowing the distance between the island-shaped organic compound layers in this manner, a display device with high definition and a large aperture ratio can be provided. Furthermore, the distance between the first electrodes of adjacent light-emitting devices can also be narrowed, for example, to 10 μm or less, 8 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less. It is preferable that the distance between the first electrodes of adjacent light-emitting devices be 2 μm or more and 5 μm or less.

[0397] 10A , it is preferable to remove mask layers 159R, 159G, and 159B. Depending on the subsequent process, sacrificial layers 158R, 158G, 158B, mask layers 159R, 159G, and 159B may remain on the display device. By removing mask layers 159R, 159G, and 159B at this stage, it is possible to prevent mask layers 159R, 159G, and 159B from remaining on the display device. For example, if a conductive material is used for mask layers 159R, 159G, and 159B, removing mask layers 159R, 159G, and 159B in advance can prevent leakage current and capacitance from remaining mask layers 159R, 159G, and 159B.

[0398] Although the present embodiment will be described taking as an example a case where the mask layers 159R, 159G, and 159B are removed, it is not necessary to remove the mask layers 159R, 159G, and 159B. For example, if the mask layers 159R, 159G, and 159B contain the aforementioned material that has a light-blocking property against ultraviolet light, it is preferable to proceed to the next step without removing them, because this protects the organic compound layer from ultraviolet light.

[0399] 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 layers 103R, 103G, and 103B during mask layer removal can be reduced compared to when a dry etching method is used.

[0400] The mask layer may also be removed by dissolving it in a solvent such as water or alcohol, such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), or glycerin.

[0401] After removing the mask layer, a drying treatment may be performed to remove water contained in the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, as well as water adsorbed on the surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. For example, heat treatment can be performed in an inert gas atmosphere or a reduced-pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50° C. or higher and 200° C. or lower, preferably 60° C. or higher and 150° C. or lower, and more preferably 70° C. or higher and 120° C. or lower. A reduced-pressure atmosphere is preferable because it enables drying at a lower temperature.

[0402] Next, as shown in FIG. 10B, an inorganic insulating film 125f, which will later become the inorganic insulating layer 125, is formed to cover the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B.

[0403] As will be described later, an insulating film that will later become the insulating layer 127 is formed in contact with the upper surface of the inorganic insulating film 125f. Therefore, it is preferable that the upper surface of the inorganic insulating film 125f has a high affinity with the material used for the insulating film (e.g., a photosensitive resin composition containing an acrylic resin). To improve this affinity, it is preferable to hydrophobize (or increase the hydrophobicity of) the upper surface of the inorganic insulating film 125f by performing a surface treatment. For example, it is preferable to perform the treatment using a silylating agent such as hexamethyldisilazane (HMDS). By hydrophobizing the upper surface of the inorganic insulating film 125f in this way, the insulating film 127f can be formed with good adhesion. The surface treatment may also be the hydrophobization treatment described above.

[0404] Subsequently, as shown in FIG. 10C, an insulating film 127f, which will later become the insulating layer 127, is formed on the inorganic insulating film 125f.

[0405] The inorganic insulating film 125f and the insulating film 127f are preferably formed by a formation method that causes less damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. In particular, since the inorganic insulating film 125f is formed in contact with the side surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, it is preferably formed by a formation method that causes less damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B than the insulating film 127f.

[0406] The inorganic insulating film 125f and the insulating film 127f are formed at a temperature lower than the heat-resistant temperatures of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, respectively. By increasing the substrate temperature during film formation, the inorganic insulating film 125f can be formed into a film with a low impurity concentration and a high barrier property against at least one of water and oxygen, even if it is thin.

[0407] The substrate temperature when forming the inorganic insulating film 125f and the insulating film 127f is preferably 60°C or higher, 80°C or higher, 100°C or higher, or 120°C or higher, and 200°C or lower, 180°C or lower, 160°C or lower, 150°C or lower, or 140°C or lower, respectively.

[0408] 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.

[0409] The inorganic insulating film 125f is preferably formed by, for example, the ALD method. The ALD method is preferable because it can reduce film formation damage and form a film with high coverage. The inorganic insulating film 125f is preferably formed as an aluminum oxide film by, for example, the ALD method.

[0410] Alternatively, the inorganic insulating film 125f may be formed by sputtering, CVD, or PECVD, which have a faster film formation rate than ALD, thereby enabling a highly reliable display device to be manufactured with high productivity.

[0411] The insulating film 127f is preferably formed by the wet film formation method described above. The insulating film 127f is preferably formed by, for example, spin coating using a photosensitive material, more specifically, using a photosensitive resin composition containing an acrylic resin.

[0412] The insulating film 127f is preferably formed using, for example, a resin composition containing a polymer, an acid generator, and a solvent. The polymer is formed using one or more types of monomers and has a structure in which one or more types of structural units (also referred to as constituent units) are regularly or irregularly repeated. As the acid generator, one or both of a compound that generates acid upon irradiation with light and a compound that generates acid upon heating can be used. The resin composition may further contain one or more of a photosensitizer, a sensitizer, a catalyst, an adhesion aid, a surfactant, and an antioxidant.

[0413] Furthermore, heat treatment (also referred to as pre-baking) is preferably performed after the insulating film 127f is formed. The heat treatment is performed at a temperature lower than the heat resistance temperature of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. The substrate temperature during the heat treatment is preferably 50° C. or higher and 200° C. or lower, more preferably 60° C. or higher and 150° C. or lower, and even more preferably 70° C. or higher and 120° C. or lower. This allows the solvent contained in the insulating film 127f to be removed.

[0414] Next, exposure is performed to expose a portion of the insulating film 127f to visible light or ultraviolet light. If a positive-type photosensitive resin composition containing an acrylic resin is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the region where the insulating layer 127 will not be formed in a later process. The insulating layer 127 is formed in the region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and around the conductive layer 152C. Therefore, visible light or ultraviolet light is irradiated onto the conductive layers 152R, 152G, 152B, and 152C. If a negative-type photosensitive material is used for the insulating film 127f, visible light or ultraviolet light is irradiated onto the region where the insulating layer 127 will be formed.

[0415] 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 mode, the insulating layer 127 is processed to have a portion overlapping with the top surface of the conductive layer 151.

[0416] 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).

[0417] Here, by providing an oxygen barrier insulating layer (e.g., an aluminum oxide film) as one or both of the sacrificial layer 158 (sacrificial layer 158R, sacrificial layer 158G, and sacrificial layer 158B) and the inorganic insulating film 125f, it is possible to reduce oxygen diffusion into the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. When the organic compound layer is irradiated with light (visible light or ultraviolet light), the organic compound contained in the organic compound layer becomes excited, which may promote a reaction with oxygen contained in the atmosphere. More specifically, when light (visible light or ultraviolet light) is irradiated to the organic compound layer in an oxygen-containing atmosphere, oxygen may bond to the organic compound contained in the organic compound layer. By providing the sacrificial layer 158 and the inorganic insulating film 125f on the island-shaped organic compound layer, it is possible to reduce oxygen in the atmosphere from bonding to the organic compound contained in the organic compound layer.

[0418] 11A, development is performed to remove the exposed areas of the insulating film 127f, forming an insulating layer 127a. The insulating layer 127a is formed in a region sandwiched between any two of the conductive layers 152R, 152G, and 152B, and in a region surrounding the conductive layer 152C. When an acrylic resin is used for the insulating film 127f, an alkaline solution, such as TMAH, can be used as the developer.

[0419] Subsequently, residues (so-called scum) remaining after development may be removed, for example, by ashing using oxygen plasma.

[0420] Etching may be performed to adjust the height of the surface of the insulating layer 127a. The insulating layer 127a may be processed by ashing using oxygen plasma, for example. Even when a non-photosensitive material is used as the insulating film 127f, the height of the surface of the insulating film 127f can be adjusted by ashing, for example.

[0421] 11B, an etching process is performed using the insulating layer 127a as a mask to remove a portion of the inorganic insulating film 125f and thin the film thickness of a portion of the sacrificial layers 158R, 158G, and 158B. This results in the formation of the inorganic insulating layer 125 below the insulating layer 127a. Furthermore, the surfaces of the thin portions of the sacrificial layers 158R, 158G, and 158B are exposed. Hereinafter, the etching process using the insulating layer 127a as a mask may be referred to as the first etching process.

[0422] The first etching treatment 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 treatment can be performed all at once, which is preferable.

[0423] By performing etching using insulating layer 127a, which has tapered side surfaces, as a mask, the side surfaces of inorganic insulating layer 125 and the upper end portions of the side surfaces of sacrificial layers 158R, 158G, and 158B can be tapered relatively easily.

[0424] When dry etching is performed, it is preferable to use a chlorine-based gas. ２ , BCl ３ , SiCl ４ , and CCl ４ The chlorine-based gas may be added with oxygen gas, hydrogen gas, helium gas, argon gas, or the like, either alone or in combination of two or more gases. By using dry etching, thin regions of the sacrificial layers 158R, 158G, and 158B can be formed with good in-plane uniformity.

[0425] The dry etching apparatus may be a dry etching apparatus having a high-density plasma source. The dry etching apparatus having a high-density plasma source may be, for example, an inductively coupled plasma (ICP) etching apparatus. Alternatively, a capacitively coupled plasma (CCP) etching apparatus having parallel-plate electrodes may be used. The capacitively coupled plasma etching apparatus having parallel-plate electrodes may be configured to apply a high-frequency voltage to one of the parallel-plate electrodes. Alternatively, it may be configured to apply a plurality of different high-frequency voltages to one of the parallel-plate electrodes. Alternatively, it may be configured to apply a high-frequency voltage of the same frequency to each of the parallel-plate electrodes. Alternatively, it may be configured to apply high-frequency voltages of different frequencies to each of the parallel-plate electrodes.

[0426] Furthermore, when dry etching is performed, by-products and the like produced by the dry etching may be deposited on the upper surface and side surfaces of insulating layer 127a, etc. Therefore, components contained in the etching gas, components contained in inorganic insulating film 125f, and components contained in sacrificial layers 158R, 158G, and 158B may be contained in insulating layer 127 after the display device is completed.

[0427] Furthermore, it is preferable to perform the first etching process by wet etching. Using the wet etching method can reduce damage to the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B compared to using the dry etching method. For example, the wet etching can be performed using an alkaline solution. For example, TMAH, an alkaline solution, can be used for wet etching of an aluminum oxide film. In this case, the wet etching can be performed by the paddle method. Note that if the inorganic insulating film 125f is formed using the same material as the sacrificial layers 158R, 158G, and 158B, the above-mentioned etching process can be performed simultaneously, which is preferable.

[0428] 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 thicknesses of the sacrificial layers 158R, 158G, and 158B are reduced. In this manner, by leaving the sacrificial layers 158R, 158G, and 158B on the organic compound layers 103R, 103G, and 103B, respectively, it is possible to prevent the organic compound layers 103R, 103G, and 103B from being damaged in subsequent processes.

[0429] Subsequently, the entire substrate is exposed to visible light or ultraviolet light, and the insulating layer 127a is preferably irradiated with the energy density of the exposure. ２ Larger, 800 mJ / cm ２ It is preferable that the dose is 0 mJ / cm or less. ２ Greater than 500 mJ / cm ２ It is more preferable to perform the following. By performing such exposure after development, the transparency of the insulating layer 127a can be improved in some cases. Furthermore, the substrate temperature required for heat treatment to transform the insulating layer 127a into a tapered shape in a later step can be reduced in some cases.

[0430] Here, the presence of an oxygen barrier insulating layer (e.g., an aluminum oxide film) as the sacrificial layers 158R, 158G, and 158B can reduce oxygen diffusion into the organic compound layers 103R, 103G, and 103B. When the organic compound layers are irradiated with light (visible light or ultraviolet light), the organic compounds contained in the organic compound layers become excited, which may promote a reaction with oxygen contained in the atmosphere. More specifically, when light (visible light or ultraviolet light) is irradiated onto the organic compound layers in an oxygen-containing atmosphere, oxygen may bond to the organic compounds contained in the organic compound layers. By providing the sacrificial layers 158R, 158G, and 158B on the island-shaped organic compound layers, it is possible to reduce oxygen from the atmosphere bonding to the organic compounds contained in the organic compound layers.

[0431] Next, heat treatment (also referred to as post-baking) is performed. The heat treatment can transform the insulating layer 127a into an insulating layer 127 having tapered side surfaces ( FIG. 11C ). The heat treatment is performed at a temperature lower than the upper temperature limit 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., and 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. The substrate temperature in this heat treatment is preferably higher than that in the heat treatment (pre-baking) performed after the formation of the insulating film 127f. This can improve adhesion between the insulating layer 127 and the inorganic insulating layer 125 and also improve the corrosion resistance of the insulating layer 127.

[0432] By leaving the sacrificial layers 158R, 158G, and 158B in a thinner state without completely removing them in the first etching process, it is possible to prevent the organic compound layers 103R, 103G, and 103B from being damaged and deteriorated in the heat treatment, thereby improving the reliability of the light-emitting device.

[0433] Depending on the material of the insulating layer 127 and the temperature, time, and atmosphere of the post-baking, a concave curved shape may be formed on the side surface of the insulating layer 127. For example, the higher the temperature or the longer the post-baking time, the more likely the shape of the insulating layer 127 is to change, and a concave curved shape may be formed.

[0434] 12A , an etching process is performed using the insulating layer 127 as a mask to remove portions of the sacrificial layers 158R, 158G, and 158B. Note that a portion of the inorganic insulating layer 125 may also be removed. As a result, openings are formed in the sacrificial layers 158R, 158G, and 158B, respectively, exposing the top surfaces of the organic compound layers 103R, 103G, 103B, and the conductive layer 152C. Note that hereinafter, the etching process using the insulating layer 127 as a mask may be referred to as a second etching process.

[0435] The end of the inorganic insulating layer 125 is covered with the insulating layer 127. Also, Fig. 12A shows an example in which a part of the end 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.

[0436] If the inorganic insulating layer 125 and the mask layer are etched together after post-baking without the first etching process, side etching may cause the inorganic insulating layer 125 and the mask layer below the edge of the insulating layer 127 to disappear, forming a cavity. Such a cavity may cause unevenness on the surface on which the common electrode 155 is formed, making the common electrode 155 more likely to be discontinuous. Even if the inorganic insulating layer 125 and the mask layer are side-etched in the first etching process, post-baking can subsequently fill the cavity with the insulating layer 127. The second etching process then etches the thinner mask layer, reducing the amount of side etching and making it less likely for a cavity to form. Even if a cavity does form, it can be extremely small. This allows the surface on which the common electrode 155 is formed to be flatter.

[0437] The insulating layer 127 may cover the entire end of the sacrificial layer 158G. For example, the end of the insulating layer 127 may droop and cover the end of the sacrificial layer 158G. Furthermore, for example, the end of the insulating layer 127 may contact the top surface of at least one of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B. As described above, if the developed insulating layer 127a is not exposed to light, the shape of the insulating layer 127 may be easily deformed.

[0438] 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 when using the dry etching method. The wet etching can be performed using an alkaline solution such as TMAH.

[0439] On the other hand, when the second etching process is performed using a wet etching method, if gaps are present between the organic compound layer 103 and the sacrificial layer 158, between the organic compound layer 103 and the inorganic insulating layer 125, and at the interface between the organic compound layer 103 and the insulating layer 175, for example, due to adhesion issues between the organic compound layer 103 and other layers, the chemical solution used in the second etching process may penetrate into the gaps and come into contact with the pixel electrodes. If the chemical solution comes into contact with both the conductive layer 151 and the conductive layer 152, the conductive layer with the lower natural potential may corrode due to galvanic corrosion. For example, if aluminum is used as the conductive layer 151 and indium tin oxide is used as the conductive layer 152, the conductive layer 152 may corrode. As a result, the yield of the display device may decrease. Furthermore, the reliability of the display device may also decrease.

[0440] As described above, by forming the insulating layer 156 so as to have a region overlapping with the side surface of the conductive layer 151 and so as to cover the conductive layer 151 and the conductive layer 152, it is possible to prevent the inorganic insulating layer 125 from being broken, and therefore it is possible to prevent the chemical solution from coming into contact with the underlying structure such as the conductive layer 151 in the second etching process, for example, thereby preventing corrosion of the pixel electrode.

[0441] As described above, by providing the insulating layer 127, the inorganic insulating layer 125, the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, it is possible to prevent connection defects caused by disconnected portions of the common electrode 155 between the light-emitting devices and an increase in electrical resistance caused by locally thin portions of the common electrode 155. As a result, the display quality of the display device of one embodiment of the present invention can be improved.

[0442] Furthermore, after exposing portions of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, a further heat treatment is performed. This heat treatment can remove water contained in each organic compound layer, water adsorbed to the surface of each organic compound layer, and the like. This heat treatment may also change the shape of the insulating layer 127. Specifically, the insulating layer 127 may extend to cover at least one of the ends of the inorganic insulating layer 125, the ends of the sacrificial layer 158R, the sacrificial layer 158G, and the sacrificial layer 158B, and the top surfaces of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B.

[0443] If the temperature of the heat treatment is too low, water contained in each organic compound layer and water adsorbed on the surface of each organic compound layer cannot be sufficiently removed. Furthermore, if the temperature of the heat treatment is too high, deterioration of the organic compound layer 103 and excessive change in the shape of the insulating layer 127 may occur. Therefore, the heat treatment is preferably performed at a temperature higher than the temperature at which water is desorbed from the organic compound layer 103 and lower than the glass transition temperature of the organic compound contained in the organic compound layer 103, and preferably lower than the glass transition temperature of the organic compound contained on the upper surface of the organic compound layer 103. Specifically, the heat treatment is preferably performed at a substrate temperature of 80°C to 130°C, preferably 90°C to 120°C, more preferably 100°C to 120°C, and even more preferably 100°C to 110°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. However, a reduced pressure atmosphere is preferred to prevent re-adsorption of water desorbed from the organic compound layer 103.

[0444] This heat treatment can sufficiently remove water contained in each organic compound layer, water adsorbed on the surface of each organic compound layer, and the like, without causing deterioration of the organic compound layer 103R, the organic compound layer 103G, and the organic compound layer 103B, or excessive change in the shape of the insulating layer 127. This can prevent deterioration in the characteristics of the light-emitting device.

[0445] 12B , the common layer 104 and the common electrode 155 are formed on the organic compound layer 103R, the organic compound layer 103G, the organic compound layer 103B, the conductive layer 152C, and the insulating layer 127. The common layer 104 and the common electrode 155 can be formed by a method such as sputtering or vacuum deposition. The common layer 104 may be formed by deposition, and the common electrode 155 may be formed by sputtering.

[0446] 12C, a 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.

[0447] Subsequently, the substrate 120 is attached over the protective layer 131 using the resin layer 122, whereby a display device can be manufactured. As described above, in the method for manufacturing a display device according to one embodiment of the present invention, the insulating layer 156 is provided on the side surfaces of the conductive layer 151 and the conductive layer 152. This can increase the yield of the display device and suppress the occurrence of defects.

[0448] As described above, in the manufacturing method of a display device according to one embodiment of the present invention, the island-shaped organic compound layers 103R, 103G, and 103B are formed by forming films over the entire surface and then processing them, rather than using a fine metal mask. This allows the island-shaped layers to be formed with uniform thicknesses. This allows a high-resolution display device or a display device with a high aperture ratio to be realized. Furthermore, even when the resolution or aperture ratio is high and the distance between subpixels is extremely short, the organic compound layers 103R, 103G, and 103B can be prevented from contacting each other in adjacent subpixels. Therefore, leakage current between subpixels can be suppressed. This prevents crosstalk and realizes a display device with extremely high contrast. Furthermore, even in a display device including tandem light-emitting devices fabricated by lithography, a display device with favorable characteristics can be provided.

[0449] The structure of this embodiment can be used in appropriate combination with structures of other embodiments.

[0450] Embodiment 4 In this embodiment, a light-emitting device of one embodiment of the present invention will be described with reference to FIGS. 13A to 13G and 14A to 14I.

[0451] [Pixel Layout] In this embodiment, pixel layouts different from that shown in Fig. 6A will be mainly described. There are no particular limitations on the arrangement of sub-pixels, and various methods can be applied. Examples of sub-pixel arrangements include a stripe arrangement, an S-stripe arrangement, a matrix arrangement, a delta arrangement, a Bayer arrangement, and a pentile arrangement.

[0452] The top shape of the sub-pixels shown in the drawings in this embodiment mode corresponds to the top shape of the light-emitting region.

[0453] The top surface shape of the subpixel may be, for example, a triangle, a quadrangle (including a rectangle and a square), a polygon such as a pentagon, a polygon with rounded corners, an ellipse, or a circle.

[0454] Furthermore, the layout of the circuits constituting the sub-pixels is not limited to the range of the sub-pixels shown in the drawings, and may be arranged outside of the range.

[0455] An S-stripe arrangement is applied to the pixel 178 shown in Fig. 13A. The pixel 178 shown in Fig. 13A is composed of three subpixels: a subpixel 110R, a subpixel 110G, and a subpixel 110B.

[0456] 13B includes a subpixel 110R having a generally trapezoidal or triangular shape with rounded corners, a subpixel 110G having a generally trapezoidal or triangular shape with rounded corners, and a subpixel 110B having a generally rectangular or hexagonal top surface shape with rounded corners. Furthermore, the subpixel 110R has a larger light-emitting area than the subpixel 110G. In this manner, the shape and size of each subpixel can be determined independently. For example, the more reliable the light-emitting device, the smaller the size of the subpixel can be.

[0457] The Pentile arrangement is applied to the pixels 124a and 124b shown in Fig. 13C. Fig. 13C shows an example in which the pixel 124a having the subpixel 110R and the subpixel 110G and the pixel 124b having the subpixel 110G and the subpixel 110B are arranged alternately.

[0458] 13D to 13F are arranged in a delta configuration. Pixel 124a has two subpixels (subpixel 110R and subpixel 110G) in the top row (first row) and one subpixel (subpixel 110B) in the bottom row (second row). Pixel 124b has one subpixel (subpixel 110B) in the top row (first row) and two subpixels (subpixel 110R and subpixel 110G) in the bottom row (second row).

[0459] Figure 13D is an example in which each subpixel has an approximately rectangular top surface shape with rounded corners, Figure 13E is an example in which each subpixel has a circular top surface shape, and Figure 13F is an example in which each subpixel has an approximately hexagonal top surface shape with rounded corners.

[0460] In Figure 13F, each subpixel is arranged inside a densely arranged hexagonal region. When focusing on one subpixel, it is arranged so that it is surrounded by six other subpixels. Furthermore, subpixels that emit light of the same color are arranged so that they are not adjacent to each other. For example, when focusing on subpixel 110R, three subpixels 110G and three subpixels 110B are arranged alternately so as to surround it.

[0461] 13G shows an example in which subpixels of each color are arranged in a zigzag pattern. Specifically, when viewed from above, the positions of the upper sides of two subpixels aligned in the row direction (for example, subpixels 110R and 110G, or subpixels 110G and 110B) are misaligned.

[0462] 13A to 13G, it is preferable that the subpixel 110R is the subpixel R that emits red light, the subpixel 110G is the subpixel G that emits green light, and the subpixel 110B is the subpixel B that emits blue light. Note that the configuration of the subpixels is not limited to this, and the colors that the subpixels emit and their order of arrangement can be determined appropriately. For example, the subpixel 110G may be the subpixel R that emits red light, and the subpixel 110R may be the subpixel G that emits green light.

[0463] In photolithography, the finer the pattern to be processed, the more significant the effect of light diffraction becomes. This impairs the fidelity of the photomask pattern when it is transferred by exposure, making it difficult to process the resist mask into the desired shape. Therefore, even if the photomask pattern is rectangular, a pattern with rounded corners is likely to be formed. As a result, the top surface shape of the subpixel may become a polygon with rounded corners, an ellipse, a circle, or the like.

[0464] Furthermore, in a manufacturing method of a light-emitting device according to one embodiment of the present invention, an organic compound layer is processed into an island shape using a resist mask. The resist film formed on the organic compound layer needs to be cured at a temperature lower than the heat resistance temperature of the organic compound layer. Therefore, depending on the heat resistance temperature of the material for the organic compound layer and the curing temperature of the resist material, the resist film may not be cured sufficiently. A resist film that is not cured sufficiently may have a shape that is different from the desired shape during processing. As a result, the top surface shape of the organic compound layer may become a polygon with rounded corners, an ellipse, a circle, or the like. For example, when a resist mask with a square top surface shape is formed, a resist mask with a circular top surface shape may be formed, resulting in a circular top surface shape of the organic compound layer.

[0465] In order to make the top surface of the organic compound layer have a desired shape, a technique for correcting a mask pattern in advance (OPC (Optical Proximity Correction) technique) may be used so that the design pattern and the transfer pattern coincide with each other. Specifically, in the OPC technique, a correction pattern is added to, for example, a corner of a figure on the mask pattern.

[0466] As shown in FIGS. 14A to 14I, a pixel can be configured to have four types of sub-pixels.

[0467] The pixel 178 shown in FIGS. 14A to 14C is arranged in a stripe pattern.

[0468] FIG. 14A shows an example in which each subpixel has a rectangular top surface shape, FIG. 14B shows an example in which each subpixel has a top surface shape that is a combination of two semicircles and a rectangle, and FIG. 14C shows an example in which each subpixel has an elliptical top surface shape.

[0469] The pixels 178 shown in FIGS. 14D to 14F are arranged in a matrix.

[0470] Figure 14D is an example in which each sub-pixel has a square top surface shape, Figure 14E is an example in which each sub-pixel has an approximately square top surface shape with rounded corners, and Figure 14F is an example in which each sub-pixel has a circular top surface shape.

[0471] 14G and 14H show an example in which one pixel 178 is configured in two rows and three columns.

[0472] 14G has three subpixels (subpixels 110R, 110G, and 110B) in the top row (first row) and one subpixel (subpixel 110W) in the bottom row (second row). In other words, pixel 178 has subpixel 110R in the left column (first column), subpixel 110G in the center column (second column), subpixel 110B in the right column (third column), and subpixels 110W across these three columns.

[0473] The pixel 178 shown in FIG. 14H has three subpixels (subpixels 110R, 110G, and 110B) in the top row (first row) and three subpixels 110W in the bottom row (second row). In other words, pixel 178 has subpixels 110R and 110W in the left column (first column), subpixels 110G and 110W in the center column (second column), and subpixels 110B and 110W in the right column (third column). By aligning the subpixels in the top and bottom rows as shown in FIG. 14H , it becomes possible to efficiently remove dust that may occur during the manufacturing process. Therefore, a light-emitting device with high display quality can be provided.

[0474] In the pixel 178 shown in FIGS. 14G and 14H, the subpixels 110R, 110G, and 110B are laid out in a stripe arrangement, which can improve the display quality.

[0475] FIG. 14I shows an example in which one pixel 178 is configured in three rows and two columns.

[0476] 14I has subpixel 110R in the top row (first row), subpixel 110G in the middle row (second row), subpixel 110B across rows 1 and 2, and one subpixel (subpixel 110W) in the bottom row (third row). In other words, pixel 178 has subpixels 110R and 110G in the left column (first column), subpixel 110B in the right column (second column), and subpixel 110W across these two columns.

[0477] In the pixel 178 shown in FIG. 14I, the layout of the subpixels 110R, 110G, and 110B is a so-called S-stripe arrangement, which can improve the display quality.

[0478] 14A to 14I is composed of four subpixels: subpixel 110R, subpixel 110G, subpixel 110B, and subpixel 110W. For example, subpixel 110R can be a subpixel that emits red light, subpixel 110G can be a subpixel that emits green light, subpixel 110B can be a subpixel that emits blue light, and subpixel 110W can be a subpixel that emits white light. Note that at least one of subpixels 110R, subpixel 110G, subpixel 110B, and subpixel 110W may be a subpixel that emits cyan light, magenta light, yellow light, or near-infrared light.

[0479] As described above, in the light-emitting device of one embodiment of the present invention, various layouts can be applied to pixels each including a subpixel having a light-emitting device.

[0480] This embodiment mode can be combined with other embodiment modes or examples as appropriate. In addition, in this specification, when a plurality of configuration examples are shown in one embodiment mode, the configuration examples can be combined as appropriate.

[0481] Embodiment 5 In this embodiment, a display device according to one embodiment of the present invention will be described.

[0482] The display device of the present embodiment can be a high-definition display device, and can therefore be used, for example, as a display unit for a wristwatch-type or bra...

Claims

1. A light-emitting device having a first electrode, a second electrode, an intermediate layer, a first hole transport layer, a second hole transport layer, a first light-emitting layer, a second light-emitting layer, and a first electron transport layer, the intermediate layer is located between the first electrode and the second electrode; the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first hole transport layer is located between the first electrode and the first light-emitting layer; the second hole transport layer is located between the intermediate layer and the second light-emitting layer, the first electron transport layer is located between the second light-emitting layer and the second electrode; the first hole transport layer has a laminate structure including a first layer and a second layer, the second layer is in contact with the first light-emitting layer, the first layer comprises a first organic compound; the second layer contains a second organic compound having a higher LUMO level than the organic compound contained in the first light-emitting layer; the first light-emitting layer has a first luminescence center substance, the second light-emitting layer has a second luminescent center substance, a difference between a maximum peak wavelength in an emission spectrum of the first luminescence center substance and a maximum peak wavelength in an emission spectrum of the second luminescence center substance is 30 nm or less; The first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of the light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device.

1. A light-emitting device having a first electrode, a second electrode, an intermediate layer, a first hole transport layer, a second hole transport layer, a first light-emitting layer, a second light-emitting layer, and a first electron transport layer, the intermediate layer is located between the first electrode and the second electrode; the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first hole transport layer is located between the first electrode and the first light-emitting layer; the second hole transport layer is located between the intermediate layer and the second light-emitting layer, the first electron transport layer is located between the second light-emitting layer and the second electrode; the second hole transport layer has a laminate structure including a third layer and a fourth layer, the fourth layer is in contact with the second light-emitting layer, the third layer comprises a third organic compound; the fourth layer contains a fourth organic compound having a higher LUMO level than an organic compound contained in the second light-emitting layer, the first light-emitting layer has a first luminescence center substance, the second light-emitting layer has a second luminescent center substance, a difference between a maximum peak wavelength in an emission spectrum of the first luminescence center substance and a maximum peak wavelength in an emission spectrum of the second luminescence center substance is 30 nm or less; a light-emitting device, wherein the first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of a light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device; 　 1. A light-emitting device having a first electrode, a second electrode, an intermediate layer, a first hole transport layer, a second hole transport layer, a first light-emitting layer, a second light-emitting layer, and a first electron transport layer, the intermediate layer is located between the first electrode and the second electrode; the first light-emitting layer is located between the first electrode and the intermediate layer, the second light-emitting layer is located between the intermediate layer and the second electrode, the first hole transport layer is located between the first electrode and the first light-emitting layer; the second hole transport layer is located between the intermediate layer and the second light-emitting layer, the first electron transport layer is located between the second light-emitting layer and the second electrode; the first hole transport layer has a laminate structure including a first layer and a second layer, the second layer is in contact with the first light-emitting layer, the first layer comprises a first organic compound; the second layer contains a second organic compound having a higher LUMO level than the organic compound contained in the first light-emitting layer; the second hole transport layer has a laminate structure including a third layer and a fourth layer, the fourth layer is in contact with the second light-emitting layer, the third layer comprises a third organic compound; the fourth layer contains a fourth organic compound having a higher LUMO level than an organic compound contained in the second light-emitting layer, the first light-emitting layer has a first luminescence center substance, the second light-emitting layer has a second luminescent center substance, a difference between a maximum peak wavelength in an emission spectrum of the first luminescence center substance and a maximum peak wavelength in an emission spectrum of the second luminescence center substance is 30 nm or less; The first light-emitting layer and the second light-emitting layer have light-emitting layers that emit light in a color gamut different from that of the light-emitting layer of at least one light-emitting device among a plurality of other light-emitting devices adjacent to the light-emitting device. 　 In any one of claims 1 to 3, A light-emitting device, wherein the first luminescent center substance and the second luminescent center substance are the same substance. 　 In claim 1 or claim 3, The light-emitting device, wherein the first organic compound includes an amine skeleton and a polycyclic aromatic ring. 　 In claim 2 or claim 3, The third organic compound comprises an amine skeleton and a polycyclic aromatic ring. 　 In claim 3, the first organic compound and the third organic compound each contain an amine skeleton and a polycyclic aromatic ring; The polycyclic aromatic ring comprises a fluorene skeleton. 　 In claim 3, A light-emitting device, wherein the first organic compound and the third organic compound are the same organic compound. 　 In claim 1 or claim 3, The second organic compound comprises an amine skeleton and a polycyclic heteroaromatic ring. 　 In claim 2 or claim 3, The fourth organic compound comprises an amine skeleton and a polycyclic heteroaromatic ring. 　 In claim 3, the second organic compound and the fourth organic compound each contain an amine skeleton and a polycyclic heteroaromatic ring; A light-emitting device, wherein the polycyclic heteroaromatic ring comprises a furan skeleton. 　 In claim 3, A light-emitting device, wherein the second organic compound and the fourth organic compound are the same organic compound. 　 In any one of claims 1 to 3, the first electron transport layer includes a layer having a fifth organic compound including a triazine skeleton, The intermediate layer comprises a mixed layer of a sixth organic compound having a phenanthroline skeleton and lithium or a lithium compound. 　 In claim 13, the first electron transport layer includes a mixed layer of a seventh organic compound having a triazine skeleton and lithium or a lithium compound, The mixed layer is located between the layer having the fifth organic compound and the second electrode. 　 In any one of claims 1 to 3, the light-emitting device comprises a second electron-transporting layer positioned between the first light-emitting layer and the intermediate layer; The second electron transport layer comprises a seventh organic compound having any one of a pyrimidine skeleton, an imidazole skeleton, and an anthracene skeleton. 　 A display device having a light-emitting device A and a light-emitting device B having a different emission color from that of the light-emitting device A, Light-emitting device A is A light-emitting device having a first electrode A, a second electrode A, an intermediate layer A, a first hole transport layer A, a second hole transport layer A, a first light-emitting layer A, a second light-emitting layer A, and an electron transport layer A, the intermediate layer A is located between the first electrode A and the second electrode A, the first light-emitting layer A is located between the first electrode A and the intermediate layer A, the second light-emitting layer A is located between the intermediate layer A and the second electrode A, the first hole transport layer A is located between the first electrode A and the first light-emitting layer A, the second hole transport layer A is located between the intermediate layer A and the second light-emitting layer A, the electron transport layer A is located between the second light-emitting layer A and the second electrode A; the first hole transport layer A has a laminate structure including a first layer A and a second layer A, the second layer A is in contact with the first light-emitting layer A, the first layer A includes a first organic compound A, the second layer A contains a second organic compound A having a higher LUMO level than the organic compound contained in the first light-emitting layer A; the second hole transport layer A has a laminate structure including a third layer A and a fourth layer A, the fourth layer A is in contact with the second light-emitting layer A, the third layer A includes a third organic compound A, the fourth layer A contains a fourth organic compound A having a higher LUMO level than the organic compound contained in the second light-emitting layer A, the first light-emitting layer A has a first light-emitting center substance A, the second light-emitting layer A has a second light-emitting center substance A, a difference between a maximum peak wavelength in the emission spectrum of the first luminescence center substance A and a maximum peak wavelength in the emission spectrum of the second luminescence center substance A is 30 nm or less; Light-emitting device B is A light-emitting device having a first electrode B, a second electrode B, an intermediate layer B, a first hole transport layer B, a second hole transport layer B, a first light-emitting layer B, a second light-emitting layer B, and an electron transport layer B, the intermediate layer B is located between the first electrode B and the second electrode B, the first light-emitting layer B is located between the first electrode B and the intermediate layer B, the second light-emitting layer B is located between the intermediate layer B and the second electrode B, the first hole transport layer B is located between the first electrode B and the first light-emitting layer B, the second hole transport layer B is located between the intermediate layer B and the second light-emitting layer B, the electron transport layer B is located between the second light-emitting layer B and the second electrode B; the first hole transport layer B contains a first organic compound B, the second hole transport layer B contains a third organic compound B, the first light-emitting layer B has a first light-emitting center substance B, the second light-emitting layer B has a second light-emitting center substance B, a difference between a maximum peak wavelength in the emission spectrum of the first luminescence center substance B and a maximum peak wavelength in the emission spectrum of the second luminescence center substance B is 30 nm or less; A display device in which the first light-emitting layer A and the second light-emitting layer A emit light in a color gamut different from that of the first light-emitting layer B and the second light-emitting layer B.

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