Light-emitting device, light-emitting apparatus, electronic device, and lighting device

Abstract

A novel light-emitting device with excellent convenience, practicality, and reliability is provided. The light-emitting device includes a second electrode sandwiched between a first electrode and an electron emission layer. The electron emission layer includes at least a light-emitting layer, an electron transport layer, and an electron injection layer. An electron transport layer is included on the light-emitting layer. An insulating layer is in contact with the sides of the light-emitting layer and the electron transport layer. An electron injection layer is included on the electron transport layer. The electron injection layer is in contact with the electron transport layer and the insulating layer.

Description

[Technical Field]

[0001] One embodiment of the present invention relates to a light-emitting device, a light-emitting apparatus, an electronic device, and a lighting equipment.

[0002] Note that one embodiment of the present invention is not limited to the above-described technical field. The technical field of one embodiment of the invention disclosed in this specification relates to an object, method, or manufacturing method. Furthermore, one embodiment of the present invention relates to a process, machine, manufacture, or 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, light-emitting devices, energy storage devices, memory devices, methods for driving these devices, or methods for manufacturing these devices. [Previous Technology]

[0003] There are known methods for manufacturing organic EL displays that can form a light-emitting layer without using a fine metal mask. As an example, one method for manufacturing an organic EL display includes: depositing a first luminescent organic material comprising a mixture of a host material and a dopant material on an electrode array including first and second pixel electrodes formed on an insulating substrate to form a first light-emitting layer as a continuous film disposed on the entire display area including the electrode array; irradiating ultraviolet light onto the portion of the first light-emitting layer above the first pixel electrode but not onto the portion above the first pixel electrode; depositing a second luminescent organic material comprising a mixture of a host material and a dopant material and different from the first luminescent organic material on the first light-emitting layer to form a second light-emitting layer as a continuous film disposed on the entire display area; and forming a counter electrode on the second light-emitting layer (Patent Document 1).

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2012-160473 [Summary of the Invention]

[0005] One objective of one embodiment of the present invention is to provide a novel light-emitting device with excellent convenience, practicality, or reliability. Furthermore, one objective of one embodiment of the present invention is to provide a novel light-emitting device with excellent convenience, practicality, or reliability. Furthermore, one objective of one embodiment of the present invention is to provide a novel electronic device with excellent convenience, practicality, or reliability. Furthermore, one objective of one embodiment of the present invention is to provide a novel lighting device with excellent convenience, practicality, or reliability.

[0006] Note that the description of these objectives does not preclude the existence of other objectives. Note that one embodiment of the present invention does not need to achieve all of the above objectives. Note that objectives other than those described above can be derived from the description in the specification, drawings, claims, etc.

[0007] One embodiment of the present invention is a light-emitting device, comprising: a second electrode with an EL layer sandwiched on a first electrode, wherein the EL layer includes at least a light-emitting layer, an electron transport layer and an electron injection layer, the light-emitting layer includes an electron transport layer, an insulating layer is in contact with the side of the light-emitting layer and the electron transport layer, the electron transport layer includes an electron injection layer, and the electron injection layer is in contact with the electron transport layer and the insulating layer.

[0008] Another embodiment of the present invention is a light-emitting device, comprising: a second electrode with an EL layer sandwiched on a first electrode, wherein the EL layer includes at least a hole injection layer, a light-emitting layer, an electron transport layer and an electron injection layer, the first electrode includes a hole injection layer, the hole injection layer includes a light-emitting layer, the light-emitting layer includes an electron transport layer, an insulating layer is in contact with the sides of the hole injection layer, the light-emitting layer and the electron transport layer, the electron transport layer includes an electron injection layer, and the electron injection layer is in contact with the electron transport layer and the insulating layer.

[0009] In the light-emitting devices with the above-mentioned structures, the electron injection layer may also include a composite material made of mixed organic compounds and electron donors, or a composite material made of mixed organic compounds and any one of alkali metals, alkaline earth metals, rare earth metals and metals belonging to Group 5, Group 7, Group 9, Group 11 or Group 13 of the periodic table.

[0010] Another embodiment of the present invention is a light-emitting device, comprising: a light-emitting device having the above-described structures; and at least one of a transistor and a substrate.

[0011] Another embodiment of the present invention is a light-emitting device including an adjacent first light-emitting device and a second light-emitting device, wherein the first light-emitting device includes a second electrode sandwiched on a first electrode with a first EL layer, the first EL layer including at least a first light-emitting layer, a first electron transport layer and an electron injection layer, the first light-emitting layer including a first electron transport layer, a first insulating layer in contact with the side of the first light-emitting layer and the first electron transport layer, and an electron injection layer included on the first electron transport layer; the second light-emitting device includes a second electrode sandwiched on a third electrode with a second EL layer, the second EL layer including at least a second light-emitting layer, a second electron transport layer and an electron injection layer, the second light-emitting layer including a second electron transport layer, a second insulating layer in contact with the side of the second light-emitting layer and the second electron transport layer, and an electron injection layer included on the first electron transport layer and the second electron transport layer, and the electron injection layer in contact with the first electron transport layer, the second electron transport layer, the first insulating layer and the second insulating layer.

[0012] Another embodiment of the present invention is a light-emitting device including adjacent first light-emitting devices and second light-emitting devices, wherein the first light-emitting device includes a second electrode sandwiched on a first electrode with a first EL layer, the first EL layer including at least a first hole injection layer, a first light-emitting layer, a first electron transport layer and an electron injection layer, the first electrode includes a first hole injection layer, the first hole injection layer includes a first light-emitting layer, the first light-emitting layer includes a first electron transport layer, a first insulating layer is in contact with the sides of the first hole injection layer, the first light-emitting layer and the first electron transport layer, and the first electron transport layer includes an electron injection layer. The second light-emitting device includes a second electrode sandwiched on a third electrode, the second EL layer including a second electrode, the second EL layer including at least a second hole injection layer, a second light-emitting layer, a second electron transport layer and an electron injection layer, the second hole injection layer on the third electrode, the second light-emitting layer on the second hole injection layer, the second electron transport layer on the second light-emitting layer, the second insulating layer in side contact with the second hole injection layer, the second light-emitting layer and the second electron transport layer, the first electron transport layer and the second electron transport layer including an electron injection layer, and the electron injection layer in contact with the first electron transport layer, the second electron transport layer, the first insulating layer and the second insulating layer.

[0013] In the light-emitting device with the above structure, the second electrode may also be located on the side of the first light-emitting layer and the second light-emitting layer, separated by the electron injection layer.

[0014] In the light-emitting device with the above structure, the second electrode may also be located on the side of the first electron transport layer, the second electron transport layer, the first light-emitting layer and the second light-emitting layer, separated by the electron injection layer.

[0015] In the light-emitting device with the above structure, the electron injection layer may also include a composite material made of mixed organic compounds and electron donors, or a composite material made of mixed organic compounds and any one of alkali metals, alkaline earth metals, rare earth metals, or metals belonging to Group 5, Group 7, Group 9, Group 11 or Group 13 of the periodic table.

[0016] One embodiment of the present invention is an electronic device, comprising: a light-emitting device having the above-described structures; and at least one of a sensor, an operation button, a speaker, and a microphone.

[0017] One embodiment of the present invention is a lighting device, comprising: a light-emitting device having the above-described structures; and a housing.

[0018] In the diagrams of this specification, components are shown as independent blocks according to their functions. However, in reality, it is difficult to completely divide components according to their functions, and a component may involve multiple functions.

[0019] In this specification, the names of the source and drain terminals of a transistor are interchanged according to the transistor's polarity and the potential applied to each terminal. Generally, in an n-channel transistor, the terminal to which a low potential is applied is called the source, and the terminal to which a high potential is applied is called the drain. Similarly, in a p-channel transistor, the terminal to which a low potential is applied is called the drain, and the terminal to which a high potential is applied is called the source. Although for convenience, the connection relationship of the transistor is sometimes described by assuming that the source and drain are fixed, in practice, the names of the source and drain are interchanged according to the aforementioned potential relationship.

[0020] In this specification, the source of a transistor refers to the source region of a semiconductor film used as part of the active layer or the source electrode connected to the semiconductor film. Similarly, the drain of a transistor refers to the drain region of a semiconductor film or the drain electrode connected to the semiconductor film. Furthermore, the gate refers to the gate electrode.

[0021] In this specification, a series connection of transistors means, for example, that only one of the source and drain terminals of the first transistor is connected to one of the source and drain terminals of the second transistor. Conversely, a parallel connection of transistors means that one of the source and drain terminals of the first transistor is connected to one of the source and drain terminals of the second transistor, and the other of the source and drain terminals of the first transistor is connected to the other of the source and drain terminals of the second transistor.

[0022] In this specification, connection means electrical connection, which is equivalent to a state in which current, voltage or potential can be supplied or transmitted. Therefore, the connection state does not necessarily have to refer to a direct connection state, but also includes a state in which current, voltage or potential can be supplied or transmitted indirectly through circuit elements such as wiring, resistors, diodes, transistors, etc.

[0023] Even when independent components are connected to each other in the circuit diagram of this specification, there are actually cases where a single conductive film functions as multiple components, such as when a portion of the wiring is used as an electrode. The scope of connections in this specification includes such cases where a single conductive film functions as multiple components.

[0024] In addition, in this specification, one of the first electrode and the second electrode of the transistor is a source electrode, and the other is a drain electrode.

[0025] According to one embodiment of the present invention, a novel light-emitting device with excellent convenience, practicality, or reliability can be provided. Furthermore, according to one embodiment of the present invention, a novel light-emitting device with excellent convenience, practicality, or reliability can be provided. Furthermore, according to one embodiment of the present invention, a novel electronic device with excellent convenience, practicality, or reliability can be provided. Furthermore, according to one embodiment of the present invention, a novel lighting device with excellent convenience, practicality, or reliability can be provided.

[0026] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not need to have all the above-described effects. Note that effects other than those described above can be learned and derived from the description in the specification, drawings, claims, etc.

Implementation Method

[0028] The embodiments will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the following description, and those skilled in the art will readily understand that its methods and details can be varied in many ways without departing from the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited only to the contents described in the embodiments shown below. Note that in the inventive structures described below, the same symbols are used in different drawings to show the same parts or parts having the same function, and repeated descriptions are omitted.

[0029] Embodiment 1 In this embodiment, the structure of a light-emitting device and a display panel according to an embodiment of the present invention will be described with reference to FIGS. 1A to 1C and FIGS. 2A to 2E.

[0030] Figures 1A to 1C are cross-sectional views illustrating an embodiment of the light-emitting device 100 of the present invention.

[0031] As shown in Figures 1A to 1C, the light-emitting device 100 includes a first electrode 101, a second electrode 102, and an EL layer 103. The first electrode 101 includes a region overlapping with the second electrode 102, and the EL layer 103 includes a region sandwiched between the first electrode 101 and the second electrode 102. The EL layer 103 has a structure in which a hole injection / transport layer 104, a light-emitting layer 113, an electron transport layer 108, and an electron injection layer 109 are sequentially stacked on the first electrode 101.

[0032] The electron injection layer 109 is a layer used to improve the efficiency of electron injection from the second electrode 102. Preferably, it is a material whose work function value is small (less than 0.5 eV) compared to the LUMO energy level value of the material used for the second electrode 102. Therefore, as the electron injection layer 109, alkali metals, alkaline earth metals, or compounds thereof, such as lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), lithium 8-(hydroxyoxoline) (Liq), lithium 2-(2-pyridyl)phenol (LiPP), lithium 2-(2-pyridyl)-3-hydroxypyridine (LiPPy), lithium 4-phenyl-2-(2-pyridyl)phenol (LiPPP), lithium oxide (LiOx), and cesium carbonate, can be used. In addition, rare earth metal compounds such as erbium fluoride (ErF3) can be used. Alternatively, an electron-electride compound can be used in the electron-injection layer 109. Examples of electron-electride compounds include mixed oxides of calcium and aluminum that have been used to add electrons at high concentrations.

[0033] Alternatively, a composite material formed by mixing an organic compound with an electron donor (donor) can be used in the electron injection layer 109. This composite material exhibits excellent electron injection and electron transport properties because electrons are generated in the organic compound through the electron donor. In this case, the organic compound is preferably a material with excellent performance in transporting the generated electrons; specifically, for example, an electron transport material (metal complex, heteroaromatic compound, etc.) used in the electron transport layer described later can be used. As the electron donor, any substance that provides electrons to the organic compound is acceptable. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Additionally, alkali metal oxides and alkaline earth metal oxides are preferred, such as lithium oxide, calcium oxide, and barium oxide. Furthermore, Lewisite such as magnesium oxide can also be used. Additionally, organic compounds such as tetrathiofulvalene (TTF) can also be used.

[0034] In addition to the materials described above, the electron injection layer 109 can also be a composite material made of a mixture of organic compounds and metals. Note that the organic compounds used here are preferably those with a LUMO (Lowest Unoccupied Molecular Orbital) energy level of -3.6 eV or higher and -2.3 eV or lower. Furthermore, non-shared electron pairs are preferred.

[0035] Therefore, as the above-mentioned organic compounds, it is preferable to use materials including heterocyclic compounds having non-shared electron pairs such as pyridine skeletons, diazine skeletons (pyrimidine, pyrazine, etc.) or triazine skeletons. Heterocyclic compounds having pyridine skeletons, heterocyclic compounds having diazine skeletons, and heterocyclic compounds having triazine skeletons will be described in detail later in this embodiment.

[0036] The metal used in the composite material formed by mixing the organic compound and the metal is preferably a transition metal belonging to Group 5, Group 7, Group 9 or Group 11 of the periodic table and a material belonging to Group 13, such as Ag, Cu, Al or In. Furthermore, a single-occupied molecular orbital (SOMO) is formed between the organic compound and the aforementioned metal.

[0037] Furthermore, the electron injection layer 109 may also have a stacked structure. The stacked structure may consist of multiple layers of different materials or multiple layers of different materials.

[0038] The materials that can be used in the electron injection layer 109 will be described in detail later in this embodiment.

[0039] In this embodiment, materials applicable to the first electrode 101, the second electrode 102, the hole injection / transport layer 104, the light-emitting layer 113, and the electron transport layer 108 will be described later. Note that the electron transport layer 108 may also have a stacked structure and may include a hole barrier layer to block holes from moving from the first electrode 101 side through the light-emitting layer 113 to the second electrode 102 side. Furthermore, as the material for forming the hole injection / transport layer 104, materials described later in this embodiment as the hole injection layer and the hole transport layer can be used. Note that the hole injection / transport layer 104 may be formed from a single layer or multiple layers. Furthermore, the hole injection layer and the hole transport layer may be formed separately. Alternatively, only one of the hole injection layer and the hole transport layer may be included instead of the hole injection / transport layer 104.

[0040] The electron injection layer 109 is part of the EL layer 103 and may have a different shape than the other layers of the EL layer 103 (hole injection / transport layer 104, light-emitting layer 113, and electron transport layer 108). Normally, when some layers of the EL layer have a different shape than other layers, the reliability and brightness of the light-emitting device may decrease because these other layers may be exposed to the atmosphere during the manufacturing process. However, when the electron injection layer 109 has a different shape than other layers, exposure to the atmosphere during the manufacturing process may occur after the electron transport layer 108 is formed on the top surface of the light-emitting layer 113. Therefore, exposure of the hole injection / transport layer 104 and the light-emitting layer 113 to the atmosphere can be prevented, thereby suppressing the decrease in the reliability and brightness of the light-emitting device 100. Therefore, in the light-emitting device 100, the electron injection layer 109 may have a different shape than the other layers of the EL layer 103 (hole injection / transport layer 104, light-emitting layer 113, and electron transport layer 108).

[0041] Note that when the electron transport layer 108 has multiple layers, even if exposure to the atmosphere or other conditions may occur after some layers of the electron transport layer 108 are formed and before other layers of the electron transport layer 108 are formed, it can sometimes suppress the decrease in reliability and brightness of the light-emitting device 100.

[0042] Figures 1B and 1C show examples of light-emitting devices 100 in which the electron injection layer 109 has a different shape from the other layers of the EL layer 103 (hole injection / transport layer 104, light-emitting layer 113 and electron transport layer 108).

[0043] As shown in FIG1B, the electron injection layer 109 and the second electrode 102 may have different shapes from the hole injection / transport layer 104, the light-emitting layer 113 and the electron transport layer 108. Since the electron injection layer 109 and the second electrode 102 can be used in multiple light-emitting devices, the manufacturing process of the light-emitting device 100 can be simplified, thereby increasing production volume.

[0044] As shown in FIG1B, the light-emitting device 100 may also include an insulating layer 107. The insulating layer 107 is in contact with a portion of the first electrode 101, the side surface of the hole injection / transport layer 104, the side surface of the light-emitting layer 113, and the side surface of the electron transport layer 108. In addition, the electron injection layer 109 is located on the side surface of the first electrode 101, the side surface of the hole injection / transport layer 104, the side surface of the light-emitting layer 113, and the side surface of the electron transport layer 108, separated by the insulating layer 107, and is in contact with the top surface of the electron transport layer 108 without being separated by the insulating layer 107. The second electrode 102 is located on the side surface of the hole injection / transport layer 104, the side surface of the light-emitting layer 113, and the side surface of the electron transport layer 108, separated by the insulating layer 107 and the electron injection layer 109, on the side surface of the first electrode 101, and on the top surface of the electron transport layer 108, separated by the electron injection layer 109. Note that the insulating layer 107 can also be said to be located between the side of the light-emitting layer 113 and the electron injection layer 109.

[0045] By having the second electrode 102 located on the side of the first electrode 101, the side of the hole injection / transport layer 104, the side of the light-emitting layer 113, and the side of the electron transport layer 108 through the insulating layer 107 and the electron injection layer 109, the conduction between the second electrode 102 and the hole injection / transport layer 104 and between the second electrode 102 and the first electrode 101 can be prevented.

[0046] It is not necessarily necessary to provide an insulating layer 107 in order to achieve the above-mentioned effect. Since the insulating layer 107 can protect the side (or end) of the hole injection / transmission layer 104, the side of the light-emitting layer 113 and the side of the electron transport layer 108, it is preferable.

[0047] It is preferable that the inclusion of the insulating layer 107 can further prevent the conduction between the second electrode 102 and the hole injection / transport layer 104, as well as the conduction between the second electrode 102 and the first electrode 101.

[0048] Therefore, the light-emitting device 100 can adopt various structures. For example, when multiple light-emitting devices 100 are arranged, the electron injection layers 109 of adjacent light-emitting devices 100 can be connected to each other and the second electrodes 102 can be connected to each other.

[0049] Materials that can be used as insulating layer 107 will be described in the following embodiments.

[0050] As shown in Figure 1C, the light-emitting layer 113 can also surround the hole injection / transport layer 104 by the following method: first, the hole injection / transport layer 104 is patterned (or only the hole injection layer is patterned); then, the light-emitting layer 113 and the electron transport layer 108 are stacked sequentially. At this time, since the light-emitting layer 113 is in contact with the top and side surfaces of the hole injection / transport layer 104, the electron injection layer 109 is not in contact with the side surfaces of the hole injection / transport layer 104, but is in contact with the side surfaces of the first electrode 101, the side surfaces of the light-emitting layer 113, and the side surfaces of the electron transport layer 108. In addition, the second electrode 102 is located on the side surfaces of the light-emitting layer 113 and the side and top surfaces of the electron transport layer 108, separated by the electron injection layer 109.

[0051] By having the end of the hole injection / transmission layer 104 surrounded by the light-emitting layer 113, even without the insulating layer 107, the conduction between the second electrode 102 and the hole injection / transmission layer 104 can be prevented.

[0052] Note that one embodiment of the present invention is not limited to the structures of FIG1B and FIG1C. For example, when an insulating layer is provided between adjacent light-emitting devices and the second electrode 102 and the electron injection layer 109 are formed on the insulating layer, sometimes the second electrode 102 and the electron injection layer 109 are not located on a part or all of the side of the first electrode 101, the side of the hole injection / transport layer 104, the side of the light-emitting layer 113, and the side of the electron transport layer 108.

[0053] Note that the structure of the light-emitting device according to one embodiment of the present invention is not limited to the structures shown in FIG1A to FIG1C. The basic structure of the light-emitting device will be described with reference to FIG2A to FIG2E.

[0054] <<Basic Structure of Light-Emitting Device>> The basic structure of the light-emitting device will be described. Figure 2A shows a light-emitting device with an EL layer having a light-emitting layer between a pair of electrodes. Specifically, an EL layer 103 is included between the first electrode 101 and the second electrode 102.

[0055] Figure 2B shows a light-emitting device with a stacked structure (series structure) comprising multiple (two layers in Figure 2B) EL layers (103a, 103b) between a pair of electrodes and a charge generation layer 106 between the EL layers. The series structure light-emitting device can realize a light-emitting device with low current stress and high reliability.

[0056] The charge generation layer 106 has the function of injecting electrons into one EL layer (103a or 103b) and injecting holes into the other EL layer (103b or 103a) when a potential difference is generated between the first electrode 101 and the second electrode 102. Thus, in FIG2B, when a voltage is applied in such a way that the potential of the first electrode 101 is higher than that of the second electrode 102, the charge generation layer 106 injects electrons into the EL layer 103a and injects holes into the EL layer 103b.

[0057] Furthermore, from the viewpoint of light extraction efficiency, the charge generation layer 106 is preferably transparent to visible light (specifically, the visible light transmittance of the charge generation layer 106 is 40% or more). In addition, it can function even if the conductivity of the charge generation layer 106 is lower than that of the first electrode 101 and the second electrode 102.

[0058] FIG2C shows the stacked structure of the EL layer 103 of a light-emitting device according to an embodiment of the present invention. Note that in this case, the first electrode 101 is used as the anode and the second electrode 102 is used as the cathode. The EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially stacked on the first electrode 101. Note that the light-emitting layer 113 may also be stacked with multiple light-emitting layers of different emitting colors. For example, a light-emitting layer containing a light-emitting material emitting red light, a light-emitting layer containing a light-emitting material emitting green light, and a light-emitting layer containing a light-emitting material emitting blue light may be stacked with or without separation from layers containing carrier transport materials. Alternatively, a light-emitting layer containing a light-emitting material emitting yellow light and a light-emitting layer containing a light-emitting material emitting blue light may be combined. Note that the stacked structure of the light-emitting layer 113 is not limited to the above structure. For example, the light-emitting layer 113 may also be stacked with multiple light-emitting layers of the same emitting color. For example, a first luminescent layer containing a blue-light-emitting material and a second luminescent layer containing a blue-light-emitting material can be stacked, with or without separation between layers containing carrier transport materials. When multiple luminescent layers of the same color are stacked, reliability can sometimes be improved compared to a single layer. Furthermore, in the tandem structure shown in FIG2B, which includes multiple EL layers, each EL layer is stacked sequentially from the anode side as described above. Additionally, when the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order of the EL layers 103 is reversed. Specifically, on the first electrode 101 of the cathode, 111 is the electron injection layer, 112 is the electron transport layer, 113 is the luminescent layer, 114 is the hole transport layer, and 115 is the hole injection layer.

[0059] By appropriately combining luminescent materials and multiple substances, the luminescent layer 113 in the EL layers (103, 103a, and 103b) can achieve fluorescent or phosphorescent emission with the desired emission color. Alternatively, the luminescent layer 113 can also have a stacked structure with different emission colors. In this case, different materials can be used as the luminescent materials and other substances for each luminescent layer. Alternatively, a structure can be adopted in which multiple EL layers (103a and 103b) as shown in FIG. 2B can have different emission colors. In this case, different materials can be used as the luminescent materials and other substances for each luminescent layer.

[0060] In addition, in a light-emitting device according to one embodiment of the present invention, for example, by making the first electrode 101 shown in FIG2C a reflective electrode, making the second electrode 102 a semi-transmissive and semi-reflective electrode and adopting an optical microcavity resonator (microcavity) structure, the light obtained from the light-emitting layer 113 in the EL layer 103 can resonate between the electrodes, thereby enhancing the light obtained through the second electrode 102.

[0061] When the first electrode 101 of the light-emitting device is a reflective electrode composed of a stacked structure of a reflective conductive material and a light-transmitting conductive material (transparent conductive film), optical adjustment can be performed by controlling the thickness of the transparent conductive film. Specifically, it is preferable to adjust it in such a way that when the wavelength of the light obtained from the light-emitting layer 113 is λ, the optical distance (product of thickness and refractive index) between the first electrode 101 and the second electrode 102 is mλ / 2 (note that m is an integer greater than or equal to 1) or a value close to it.

[0062] Furthermore, in order to amplify the desired light (wavelength: λ) obtained from the light-emitting layer 113, it is preferable to adjust the optical distance from the first electrode 101 to the region (light-emitting region) in the light-emitting layer 113 where the desired light can be obtained, and the optical distance from the second electrode 102 to the region (light-emitting region) in the light-emitting layer 113 where the desired light can be obtained, both to be (2m'+1)λ / 4 (note that m' is an integer greater than or equal to 1) or a value close to that. Note that the "light-emitting region" described here refers to the recombination region of holes and electrons in the light-emitting layer 113.

[0063] By performing the above optical adjustments, the spectrum of the specific monochromatic light that can be obtained from the light-emitting layer 113 can be narrowed, thereby obtaining light emission with good color purity.

[0064] Furthermore, in the above-described case, strictly speaking, the optical distance between the first electrode 101 and the second electrode 102 can be considered as the total thickness from the reflective region in the first electrode 101 to the reflective region in the second electrode 102. However, since it is difficult to accurately determine the positions of the reflective regions in the first electrode 101 and the second electrode 102, the above-described effect can be sufficiently obtained by assuming any position in the first electrode 101 and the second electrode 102 as a reflective region. Furthermore, strictly speaking, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be considered as the optical distance between the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer from which the desired light is obtained. However, since it is difficult to accurately determine the positions of the reflective region in the first electrode 101 and the light-emitting region in the light-emitting layer from which the desired light is obtained, the above-described effect can be sufficiently obtained by assuming any position in the first electrode 101 as a reflective region and any position in the light-emitting layer from which the desired light is obtained as a light-emitting region.

[0065] The light-emitting device shown in Figure 2D is a light-emitting device with a series structure and a microcavity structure, so different wavelengths of light (monochromatic light) can be extracted from each EL layer (103a, 103b). Therefore, it is not necessary to coat them separately (e.g., coating with R, G, B) to obtain different emission colors. Thus, high resolution can be easily achieved. In addition, it can be combined with a color layer (color filter). Furthermore, the emission intensity in the front direction with a specific wavelength can be enhanced, thereby achieving low power consumption.

[0066] The light-emitting device shown in Figure 2E is an example of the series-connected structure of the light-emitting device shown in Figure 2B. As shown in the figure, it has a structure in which three EL layers (103a, 103b, 103c) are stacked with charge-generating layers (106a, 106b) sandwiched between them. The three EL layers (103a, 103b, 103c) each include a light-emitting layer (113a, 113b, 113c), and the emission colors of each light-emitting layer can be freely combined. For example, light-emitting layers 113a and 113c can emit blue light, and light-emitting layer 113b can emit one or more of red, green, and yellow light. Alternatively, for example, light-emitting layers 113a and 113c can emit red light, and light-emitting layer 113b can emit one or more of blue, green, and yellow light.

[0067] Furthermore, in the light-emitting device of one embodiment of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (transparent electrode, semi-transmissive-semi-reflective electrode, etc.). When the light-transmitting electrode is a transparent electrode, the visible light transmittance of the transparent electrode is 40% or more. Furthermore, when the electrode is a semi-transmissive-semi-reflective electrode, the visible light reflectance of the semi-transmissive-semi-reflective electrode is 20% or more and 80% or less, preferably 40% or more and 70% or less. Additionally, the resistivity of these electrodes is preferably 1 × 10⁻² Ωcm or less.

[0068] Furthermore, in the light-emitting device of one embodiment of the present invention described above, when one of the first electrode 101 and the second electrode 102 is a reflective electrode (reflective electrode), the visible light reflectance of the reflective electrode is 40% or more and 100% or less, preferably 70% or more and 100% or less. Additionally, the resistivity of the electrode is preferably 1 × 10⁻² Ωcm or less.

[0069] <<Specific Structure of the Light-Emitting Device>> Next, the specific structure of a light-emitting device according to one embodiment of the present invention will be described with reference to FIGS. 2A to 2E. Furthermore, FIG. 2D, which has a series structure, will be described here. Note that the light-emitting devices of FIGS. 2A and 2C, which have a single structure, also have the same EL layer structure. Furthermore, in the case where the light-emitting device shown in FIG. 2D has a microcavity structure, a reflective electrode is formed as the first electrode 101, and a semi-transmissive / semi-reflective electrode is formed as the second electrode 102. Thus, the electrodes can be formed in a single layer or in a stack using a desired electrode material alone or using multiple electrode materials. Additionally, the second electrode 102 is formed after the EL layer 103b is formed, using the same material as described above.

[0070] <First Electrode and Second Electrode> The materials used to form the first electrode 101 and the second electrode 102 can be appropriately combined to satisfy the functions of the two electrodes. For example, metals, alloys, conductive compounds, and mixtures thereof can be appropriately used. Specifically, examples include In-Sn oxide (also known as ITO), In-Si-Sn oxide (also known as ITSO), In-Zn oxide, and In-W-Zn oxide. In addition to the above, 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 appropriately combined therein, can be used. In addition to the above, elements belonging to Group 1 or Group 2 of the periodic table (e.g., rare earth metals such as lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), europium (Eu), ytterbium (Yb), alloys of them appropriately combined, and graphene, etc., can be used.

[0071] In the light-emitting device shown in FIG2D, when the first electrode 101 is the anode, the hole injection layer 111a and the hole transport layer 112a of the EL layer 103a are sequentially deposited on the first electrode 101 by vacuum evaporation. After the EL layer 103a and the charge generation layer 106 are formed, the hole injection layer 111b and the hole transport layer 112b of the EL layer 103b are sequentially deposited on the charge generation layer 106 in the same manner as described above.

[0072] <Hole Injection Layer> The hole injection layer (111, 111a, 111b) is a layer in which holes are injected from the first electrode 101 of the anode and the charge generation layer (106, 106a, 106b) into the EL layer (103, 103a, 103b), and contains one or both of an organic acceptor material and a material with high hole injection capability.

[0073] Organic acceptor materials can generate holes in organic compounds by charge separation between them and other organic compounds whose HOMO energy level is close to the LUMO energy level. Therefore, compounds having electron-withdrawing groups (e.g., halogen or cyano groups) such as quinone dimethane derivatives, tetrachlorobenzoquinone derivatives, and hexaazatribenzene derivatives can be used as organic acceptor materials. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinone dimethyl ether (abbreviated as F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyano-p-quinone dimethyl ether, chloroquinone, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatribenzene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinone dimethyl ether (abbreviated as F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malonitrile can be used. In organic acceptor materials, compounds such as HAT-CN, in particular, with electron-withdrawing groups bonded to fused aromatic rings having multiple heteroatoms, exhibit high acceptor properties and thermal stability, making them especially desirable. In addition, [3] axylene derivatives containing electron-withdrawing groups (especially halogens such as fluorine groups or cyano groups) are preferred due to their very high electron acceptability. Specifically, the following can be used: α,α',α”-1,2,3-cycloalkyltrimethylenetri[4-cyano-2,3,5,6-tetrafluorophenylacetonitrile], α,α',α”-1,2,3-cyclopropyltrimethylenetri[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)phenylacetonitrile], α,α',α”-1,2,3-cycloalkyltrimethylenetri[2,3,4,5,6-pentafluorophenylacetonitrile], etc.

[0074] As a material with high hole injection capability, oxides of metals belonging to Groups 4 to 8 of the periodic table (such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, and other transition metal oxides) can be used. Specifically, examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferred because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. In addition to the above, phthalocyanine compounds such as phthalocyanine (abbreviated as H2Pc) or copper phthalocyanine (CuPc) can be used.

[0075] In addition, aromatic amine compounds of low molecular weight compounds such as 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviated as TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviated as MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N-N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4 '-Diamine (abbreviated as DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as PCzPCN1), etc.

[0076] In addition, polymeric compounds (oligomers, dendritic polymers, or polymers, etc.) can be used, such as poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD), etc. Alternatively, polymeric compounds containing acids can be used, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviated as PEDOT / PSS), polyaniline / poly(styrenesulfonic acid) (abbreviated as PAni / PSS), etc.

[0077] As a material with high hole injection capability, a composite material comprising a hole transport material and the aforementioned organic acceptor material (electron acceptor material) can also be used. In this case, electrons are extracted from the hole transport material by the organic acceptor material to generate a hole in the hole injection layer 111, and the hole is injected into the light-emitting layer 113 via the hole transport layer 112. Alternatively, the hole injection layer 111 can be a single layer composed of a composite material comprising a hole transport material and an organic acceptor material (electron acceptor material), or it can be a stack of layers formed using hole transport materials and organic acceptor materials (electron acceptor materials) respectively.

[0078] As a hole transport material, it is preferable to use a material with a hole mobility of 1×10⁻⁶ cm² / Vs or higher when the square root of the electric field strength [V / cm] is 600. Alternatively, any material other than the one mentioned above may be used as long as its hole transport capability is higher than its electron transport capability.

[0079] As a hole transport material, it is preferable to use materials with high hole transport properties such as π-electron-rich heteroaromatic compounds (e.g., carbazole derivatives, furan derivatives or thiophene derivatives) and aromatic amines (compounds containing aromatic amine skeletons).

[0080] As the above-mentioned carbazole derivatives (compounds having a carbazole skeleton), examples include bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives) and aromatic amines having a carbazole group.

[0081] Specifically, examples of the above-mentioned bicarbazole derivatives (e.g., 3,3'-bicarbazole derivatives) include 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 9,9'-bis(1,1'-biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9,9'-bis(1,1'-biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviated as BisBPCz), 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviated as mBPCCBP), and 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP), etc.

[0082] In addition, as aromatic amines having a carbazole group, examples specifically include 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-furo-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviated as: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-furo-2-amine (abbreviated as: PCBBiF), 4,4'-diphenyl-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as: PCBi1BP), 4-(1-naphthyl) 4,4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-bis(1-naphthyl)-4”-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCCNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl)-N,N'-diphenylphenyl-1,3-diamine (abbreviation: PCA2B), N,N',N”-triphenyl-N,N',N”-tri(9-phenylcarbazole-3-yl)phenyl-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H- Carbazole-3-yl)phenyl]furan-2-amine (abbreviated as: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-difuran-2-amine (abbreviated as: PCBASF), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviated as: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]- 9-Phenylecarbazole (abbreviated as PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzDPA2), 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (abbreviated as PCzTPN2), 2-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]spiro-9,9'-difenotan (abbreviated as PCASF), N-[4-(9H-carbazole-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviated as YGA1BP), N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfenotan-2,7-Diamine (abbreviated as YGA2F), 4,4',4”-Tris(carbazole-9-yl)triphenylamine (abbreviated as TCTA), etc.

[0083] Note that, in addition to the above, other examples of carbazole derivatives include 3-[4-(9-phenanthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviated as mCP), 4,4'-bis(N-carbazolyl)biphenyl (abbreviated as CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviated as CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), and 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated as CzPA), etc.

[0084] Specifically, examples of the above-mentioned furan derivatives (compounds having a furan skeleton) include 4,4',4”-(benzene-1,3,5-triyl)tris(dibenzofuran) (abbreviated as: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-en-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as: mmDBFFLBi-II).

[0085] Specifically, examples of the above-mentioned thiophene derivatives (compounds having a thiophene skeleton) include 1,3,5-tris(dibenzothiophene-4-yl)-benzene (abbreviated as: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-en-9-yl)phenyl]dibenzothiophene (abbreviated as: DBTFLP-III), and 4-[4-(9-phenyl-9H-en-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as: DBTFLP-IV), etc.

[0086] Specifically, examples of the aforementioned aromatic amines include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviated as TPD), 4,4'-bis[N-(spiro-9,9'-dien-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylen-9-yl)triphenylamine (abbreviated as BPAFLP), 4-phenyl-3'-(9-phenylen-9-yl)triphenylamine (abbreviated as mBPAFLP), and N-(9,9-dimethyl-9H-en-2-yl)-N -{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-en-2-yl)amino]-9H-en-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-en-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-dienyl (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-dienyl (abbreviation: DPA2SF), 4,4',4”-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4 ',4”-Tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4”-Tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m-MTDATA), N,N'-Di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), DNTPD, 1,3,5-Tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP) N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4”-phenyltriphenylamine (abbreviation: BnfBB1BP), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-benzidine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4”-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4”-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4”-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4”-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβ) NB-03), 4,4'-diphenyl-4”-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4”-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4”-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4”-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4”-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenyl)-4' -(2-naphthyl)-4”-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4”-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenyl)-4'-[4-(2-naphthyl)phenyl]-4”-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4”-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4- [3-Phenylacetyl-9H-carbazole-9-yl)phenyl]tri(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazole-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4”-phenyltriphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobis[9H-furan]-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobis[9H-furan]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobis[9H-furan]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-furan-2-yl)-9,9'-spirobis(9H-furan)-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-furan-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4 4'-[4-(9-phenylenzo-9-yl)phenyl]triphenylamine (abbreviated as BPAFLBi), N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-4-amine, N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-3-amine, N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-2-amine, N,N-bis(9,9-dimethyl-9H-enzo-2-yl)-9,9'-spirobis-9H-enzo-1-amine, etc.

[0087] In addition, as hole-transporting materials, polymeric compounds (oligomers, dendritic polymers, polymers, etc.) can be used, such as poly(N-vinylcarbazole) (PVK), poly(4-vinyltriphenylamine) (PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (Poly-TPD), etc. Alternatively, polymeric compounds containing acids can be used, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) or polyaniline / poly(styrenesulfonic acid) (PAni / PSS), etc.

[0088] Note that the hole transport material is not limited to the above-mentioned materials, and one or more combinations of known materials can be used as the hole transport material.

[0089] Note that the hole injection layers (111, 111a, 111b) can be formed using various known film formation methods, such as vacuum evaporation.

[0090] <Hole Transport Layer> The hole transport layers (112, 112a, 112b) are layers that transport holes injected from the first electrode 101 through the hole injection layers (111, 111a, 111b) to the light-emitting layers (113, 113a, 113b, 113c). Furthermore, the hole transport layers (112, 112a, 112b) are layers containing a hole-transporting material. Therefore, as the hole transport layers (112, 112a, 112b), a hole-transporting material suitable for use in the hole injection layers (111, 111a, 111b) can be used.

[0091] Note that in a light-emitting device according to one embodiment of the present invention, the same organic compound as that used in the hole transport layers (112, 112a, 112b) can be used in the light-emitting layers (113, 113a, 113b, 113c). Using the same organic compound in both the hole transport layers (112, 112a, 112b) and the light-emitting layers (113, 113a, 113b, 113c) is preferable because it allows for efficient hole transport from the hole transport layers (112, 112a, 112b) to the light-emitting layers (113, 113a, 113b, 113c).

[0092] <Emitting Layer> The emitting layers (113, 113a, 113b, 113c) are layers containing luminescent materials. For the luminescent materials that can be used in the emitting layers (113, 113a, 113b, 113c), materials exhibiting luminescent colors such as blue, purple, blue-violet, green, yellow-green, yellow, orange, and red can be appropriately used. Furthermore, when multiple emitting layers are included, by using different luminescent materials in each emitting layer, a structure exhibiting different luminescent colors can be achieved (for example, white light can be obtained by combining luminescent colors that are complementary colors). Moreover, a stacked structure in which one emitting layer contains different luminescent materials can also be used.

[0093] In addition, the light-emitting layers (113, 113a, 113b, 113c) may contain one or more organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0094] Note that when multiple host materials are used in the light-emitting layers (113, 113a, 113b, 113c), the newly added second host material is preferably a material with a band gap larger than that of the conventional guest material and the first host material. Furthermore, it is preferable that the lowest singlet excitation energy level (S1 level) of the second host material is higher than the S1 level of the first host material, and that the lowest singlet excitation energy level (T1 level) of the second host material is higher than the T1 level of the guest material. Furthermore, it is preferable that the lowest triplet excitation energy level (T1 level) of the second host material is higher than the T1 level of the first host material. By employing the above structure, an excited-state complex can be formed from the two host materials. Note that for efficient formation of the excited-state complex, it is particularly preferable to combine a compound that readily accepts holes (a hole-transporting material) and a compound that readily accepts electrons (an electron-transporting material). Furthermore, by employing the above structure, high efficiency, low voltage, and long lifetime can be achieved simultaneously.

[0095] Note that, as the organic compounds used as the aforementioned host materials (including the first host material and the second host material), as long as they meet the conditions for host materials used in the luminescent layer, organic compounds such as hole-transporting materials that can be used in the aforementioned hole transport layers (112, 112a, 112b) and electron transporting materials that can be used in the electron transport layers (114, 114a, 114b) described later can be used. Exciplexes formed from multiple organic compounds (the aforementioned first host material and the second host material) can also be used. Furthermore, exciplexes formed from multiple organic compounds in the excited state have the function of converting triple excitation energy into single excitation energy because the difference between the S1 and T1 energy levels is extremely small. As a combination of multiple organic compounds forming the exciplex, it is preferable, for example, that one has a π-electron-deficient heteroaryl ring and the other has a π-electron-rich heteroaryl ring. Furthermore, as one of the combinations forming the exciplex, phosphorescent materials such as iridium, rhodium, platinum-based organometallic complexes or metal complexes can also be used.

[0096] There are no particular restrictions on the luminescent material that can be used in the luminescent layer (113, 113a, 113b, 113c). A luminescent material that converts single excitation energy into light in the visible light region or a luminescent material that converts triple excitation energy into light in the visible light region can be used.

[0097] <<Luminescent Material Converting Single Excitation Energy into Luminescence>> Examples of luminescent materials that convert single excitation energy into luminescence for use in luminescent layers (113, 113a, 113b, 113c) include fluorescent materials (fluorescent materials), such as pyrene derivatives, anthracene derivatives, triphenylene derivatives, fenestration derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoline derivatives, quinoline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives. Pyrene derivatives, in particular, have a high luminescence quantum yield and are therefore preferred. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-en-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-en-9-yl)phenyl]pyrene-1,6-diamine (abbreviated as: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviated as: 1,6FrAPrn), and N,N'-bis(dibenzothiophene-2-yl)-N,N' N,N'-(pyrene-1,6-diamine) (abbreviated as: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviated as: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviated as: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviated as: 1,6BnfAPrn-03), etc.

[0098] In addition, 5,6-bis[4-(10-phenyl-9-anthrayl)phenyl]-2,2'-bipyridine (abbreviated as: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthrayl)biphenyl-4-yl]-2,2'-bipyridine (abbreviated as: PAPP2BPy), and N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine can be used. (Abbreviation: YGA2S), 4-(9H-carbazole-9-yl)-4'-(10-phenyl-9-anthrayl)triphenylamine (Abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthrayl)triphenylamine (Abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole-3-amine (Abbreviation: PCAPA), 4-( 10-Phenyl-9-anthrayl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCPAPA), 4-[4-(10-phenyl-9-anthrayl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCPABA), perylene, 2,5,8,11-tetra-(tertiary butyl)perylene (abbreviation: TBP), N,N”-(2-tertiary butyl anthracene-9,10-diyl di N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-9H-carbazole-3-amine (2PCAPPA), N-[4-(9,10-diphenyl-2-anthrayl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (2DPAPPA), etc.

[0099] In addition, N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthrayl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthrayl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthrayl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), and 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YG) can also be used. ABPhA), N,N,9-triphenylanthracene-9-amine (abbreviated as: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviated as: DPQd), fluorene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetraphenyl (abbreviated as: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]vinyl}-6-methyl-4H-pyran-4-ylidene)malonitrile (abbreviated as: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazin-9-yl)vinyl]-4H-pyran-4-ylidene}malonitrile (abbreviated as: DCM2), N,N,N ',N'-Tetra(4-methylphenyl)tetraphenyl-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetra(4-methylphenyl)acenaphthene[1,2-a]propadiene-3,10-diamine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]] Quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: DCJTB), 2-(2,6-bis{2-[4-(dimethylamino)phenyl]vinyl}-4H-pyran-4-ylidene)malonium (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinazine-9-yl)vinyl]-4H-pyran-4-ylidene}malonium (abbreviation: BisDCJTM), 1,6BnfAPrn-03, 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;[6,7-b']bisbenzofuran (abbreviated as: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-anilino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as: 3,10FrA2Nbf(IV)-02), etc. In particular, pyrene diamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 can be used.

[0100] <<Light-emitting material that converts triple excitation energy into light emission>> Next, as a light-emitting material that can be used in the light-emitting layer 113 to convert triple excitation energy into light emission, examples include phosphorescent materials (phosphorescent materials) or thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

[0101] A phosphorescent material is a compound that emits phosphorescence but not fluorescence at any temperature within a temperature range above low temperature (e.g., 77 K) and below room temperature (i.e., above 77 K and below 313 K). Preferably, the phosphorescent material contains a metallic element with strong spin-orbit interactions, such as organometallic complexes, metal complexes (platinum complexes), rare-earth metal complexes, etc. Specifically, it preferably contains a transition metal element, particularly preferably a platinum group element (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)), and especially preferably iridium. Iridium is preferred because it increases the probability of a direct transition between the singlet ground state and the triplet excited state.

[0102] <<phosphorescent substances (450nm or more and 570nm or less: blue or green)>>As phosphorescent substances that exhibit blue or green color and whose emission spectrum has a peak wavelength of 450nm or more and 570nm or less, the following substances can be cited.

[0103] For example, examples include tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviated as: [Ir(mpptz-dmp)3]), tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazole)iridium(III) (abbreviated as: [Ir(Mptz)3]), and tris[4-(3-biphenyl)-5-isopropyl-3-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as: [Ir(iPrptz-3b)3] Organometallic complexes with a 4H-triazole skeleton, such as tri[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(iPr5btz)3]); and organometallic complexes with a 1H-triazole skeleton, such as tri[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazole]iridium(III) (abbreviated as [Ir(Mptz1-mp)3]) and tri(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazole)iridium(III) (abbreviated as [Ir(Prptz1-Me)3]). Organometallic complexes with an imidazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazolium]iridium(III) (abbreviated as [Ir(iPrpmi)3]) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviated as [Ir(dmpimpt-Me)3]); and bis[2-(4',6'-difluorophenyl)pyridinium-N,C2']iridium(III)tetra(1-pyrazolyl)boron. Organometallic complexes with phenylpyridine derivatives having electron-withdrawing groups as ligands include acetones such as FIr6, bis[2-(4',6'-difluorophenyl)pyridin-N,C2']iridium(III)pyridinecarboxylate (FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridin-N,C2'}iridium(III)pyridinecarboxylate ([Ir(CF3ppy)2(pic)]), and bis[2-(4',6'-difluorophenyl)pyridin-N,C2']iridium(III)acetoacetone (FIr(acac)).

[0104] <<phosphorescent substances (495nm or higher and 590nm or lower: green or yellow)>>As phosphorescent substances that exhibit green or yellow color and whose emission spectrum has a peak wavelength of 495nm or higher and 590nm or lower, the following substances can be cited.

[0105] For example, examples include tris(4-methyl-6-phenylpyrimidine)iridium(III) (abbreviated as: [Ir(mppm)3]), tris(4-tert-butyl-6-phenylpyrimidine)iridium(III) (abbreviated as: [Ir(tBuppm)3]), (acetylacetone)bis(6-methyl-4-phenylpyrimidine)iridium(III) (abbreviated as: [Ir(mppm)2(acac)]), (acetylacetone)bis(6-tert-butyl-4-phenylpyrimidine)iridium(III) (abbreviated as: [Ir(tBuppm)2(acac)]), (acetylacetone)bis[6-(2-norborneol)-4-phenylpyrimidine]iridium(III) (abbreviated as: [Ir(nbppm)2( Organometallic iridium complexes with a pyrimidine skeleton, such as acetyl acetone bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidine]iridium(III) (abbreviated as [Ir(mpmppm)2(acac)]), acetyl acetone bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviated as [Ir(dmppm-dmp)2(acac)]), and acetyl acetone bis(4,6-diphenylpyrimidine)iridium(III) (abbreviated as [Ir(dppm)2(acac)]); acetyl acetone bis(3,5-dimethyl-2-phenylpyrazine)iridium Organometallic iridium complexes with a pyrazine skeleton, such as (III) (abbreviated as [Ir(mppr-Me)2(acac)]), (acetyl acetone)bis(5-isopropyl-3-methyl-2-phenylpyrazine)iridium(III) (abbreviated as [Ir(mppr-iPr)2(acac)]); tri(2-phenylpyridinium-N,C2')iridium(III) (abbreviated as [Ir(ppy)3]), bis(2-phenylpyridinium-N,C2')iridium(III)acetone (abbreviated as [Ir(ppy)2(acac)]), bis(benzo[h]quinoline)iridium(III)acetone (abbreviated as [Ir(bzq)2(acac)]), tri(benzo[h]quinoline Organometallic iridium complexes with a pyridine skeleton include iridium(III) (abbreviated as [Ir(bzq)3]), tris(2-phenylquinoline-N,C2')iridium(III) (abbreviated as [Ir(pq)3]), bis(2-phenylquinoline-N,C2')iridium(III)acetone (abbreviated as [Ir(pq)2(acac)]), bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-phenyl-2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviated as [Ir(ppy)2(4dppy)]), and bis[2-(2-pyridyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridyl-κN)phenyl-κC].Organometallic complexes such as bis(2,4-diphenyl-1,3-acetazol-N,C2')iridium(III)acetoacetone (abbreviated as [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridine-N,C2'}iridium(III)acetoacetone (abbreviated as [Ir(p-PF-ph)2(acac)]), and bis(2-phenylbenzothiazole-N,C2')iridium(III)acetoacetone (abbreviated as [Ir(bt)2(acac)]), and rare earth metal complexes such as tri(acetoacetone-(monoporphyrin)thiazolinium(III) (abbreviated as [Tb(acac)3(Phen)]).

[0106] <<phosphorescent substances (570nm or more and 750nm or less: yellow or red)>>As phosphorescent substances that exhibit yellow or red color and whose emission spectrum has a peak wavelength of 570nm or more and 750nm or less, the following substances can be cited.

[0107] For example, examples include (diisobutyramethane)bis[4,6-bis(3-methylphenyl)pyrimidinium]iridium(III) (abbreviated as: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinium](dineoptidomethane)iridium(III) (abbreviated as: [Ir(5mdppm)2(dpm)]), and (dineoptidomethane)bis[4,6-bis( Organometallic complexes with a pyrimidine skeleton, such as [Ir(d1npm)2(dpm)](naphthyl-1-yl)pyrimidinium(III) (abbreviated as [Ir(d1npm)2(dpm)]); bis(2,3,5-triphenylpyrazine)iridium(III) (abbreviated as [Ir(tppr)2(acac)], bis(2,3,5-triphenylpyrazine)(dineopentylmethane)iridium(III) (abbreviated as [Ir(tppr)2)2) (dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedione-κ2O,O')iridium(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3- (3,5-Dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedione-κ2O,O')iridium(III) (abbreviated as: [Ir(dmdppr-dmCP)2(dpm)]), bis[2-(5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN)-4,6-dimethylphenyl-κC] Organometallic complexes with a pyrazine skeleton, such as (2,2',6,6'-tetramethyl-3,5-heptadecyl-κ20,0')iridium(III) (abbreviated as [Ir(dmdppr-dmp)2(dpm)]), (acetylacetone)bis[2-methyl-3-phenylquinoxalinato]-N,C2']iridium(III) (abbreviated as [Ir(mpq)2(acac)]), (acetylacetone)bis(2,3-diphenylquinoxalinato)-N,C2']iridium(III) (abbreviated as [Ir(dpq)2(acac)]), (acetylacetone)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviated as [Ir(Fdpq)2(acac)]).Organometallic complexes with a pyridine skeleton, such as tris(1-phenylisoquinoline-N,C2')iridium(III) (abbreviated as [Ir(piq)3]), bis(1-phenylisoquinoline-N,C2')iridium(III)acetophenone (abbreviated as [Ir(piq)2(acac)]), and bis[4,6-dimethyl-2-(2-quinoline-κN)phenyl-κC](2,4-pentanedione-κ2O,O')iridium(III) (abbreviated as [Ir(dmpqn)2(acac)]); 2,3,7,8, Platinum complexes such as 12,13,17,18-octaethyl-21H,23H-violet platinum(II) (abbreviated as [PtOEP]); and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedione) europium(III) (abbreviated as [Eu(DBM)3(Phen)]) and tris[1-(2-thiophenecarboxyl)-3,3,3-trifluoroacetone] (abbreviated as [Eu(TTA)3(Phen)]).

[0108] <<TADF Material>> Furthermore, the following materials can be used as TADF materials. TADF materials refer to materials with a small energy difference between the S1 and T1 energy levels (preferably 0.2 eV or less) that can utilize minimal thermal energy to upconvert a triplet excited state into a singlet excited state (inverse intersystem crossing) and efficiently emit light (fluorescence) from the singlet excited state. The conditions for efficiently obtaining thermally activated delayed fluorescence are as follows: the energy difference between the triplet and singlet excited energy levels is 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. The delayed fluorescence emitted by TADF materials refers to luminescence with the same spectrum as ordinary fluorescence but with a very long lifetime. Its lifetime is 1 × 10⁻⁶ seconds or more, preferably 1 × 10⁻³ seconds or more.

[0109] Examples of TADF materials include fullerenes and their derivatives, acridine derivatives such as proflavin, and eosin. Additionally, examples include metallic violets containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metallic violet compounds include, for example, protoviolet-tin fluoride complex (SnF2(Proto IX)), mesoviolet-tin fluoride complex (SnF2(Meso IX)), hematoviolet-tin fluoride complex (SnF2(Hemato IX)), tetramethyl copropisyl tin fluoride complex (SnF2(Copro III-4Me)), octaethylviolet-tin fluoride complex (SnF2(OEP)), protoviolet-tin fluoride complex (SnF2(Etio I)), and octaethylviolet-platinum chloride complex (PtCl2OEP).

[0110] [Chemical Formula 1]

[0111] In addition to the above, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazole-11-yl)-1,3,5-triazine (abbreviated as: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as: PCCzPTzn), 2- [4-(10H-phenanthroline-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenanthroline-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-oxanthracene-9-one (abbreviation: ACR) XTN), bis[4-(9,9-dimethyl-9,10-dihydroacrylidine)phenyl] ion (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acrylidine-9,9'-anthraphen]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)benzofurano[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4- Heterocyclic compounds such as (9'-phenyl-3,3'-bi-9H-carbazole-9-yl)phenyl]benzofuran[3,2-d]pyrimidine (abbreviation: 4PCCzPBfpm), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), etc., possessing π-electron-rich and π-electron-deficient heterocyclic aromatic rings.

[0112] In addition, among substances in which π-electron-rich heteroaromatic rings and π-electron-deficient heteroaromatic rings are directly bonded, the donor nature of the π-electron-rich heteroaromatic ring and the acceptor nature of the π-electron-deficient heteroaromatic ring are both strong, and the energy difference between the singlet excited state and the triplet excited state becomes smaller, so it is particularly preferred.

[0113] [Chemical Formula 2]

[0114] In addition to the above, nanostructures of transition metal compounds with a perovskite structure can be cited as materials capable of converting triple excitation energy into luminescence. Metal halide perovskite nanostructures are particularly preferred. Nanoparticles and nanorods are preferred as such nanostructures.

[0115] In the light-emitting layers (113, 113a, 113b, 113c), as an organic compound (host material, etc.) that combines the above-mentioned light-emitting material (guest material), one or more substances whose band gap is larger than that of the light-emitting material (guest material) can be used.

[0116] <<Fluorescent Host Material>> When the luminescent material used in the luminescent layers (113, 113a, 113b, 113c) is a fluorescent luminescent material, the organic compound (host material) used in combination with the luminescent material is preferably an organic compound with a high energy level of its singlet excited state and a low energy level of its triplet excited state, or an organic compound with a high fluorescence quantum yield. Therefore, any organic compound that meets the above conditions can be used, such as the hole transport material (described above) and the electron transport material (described later) shown in this embodiment.

[0117] Although some of the content is repeated with the specific examples above, from the viewpoint that it is better to use it in combination with luminescent materials (fluorescent materials), examples of fused polycyclic aromatic compounds such as anthracene derivatives, fused tetrabenzene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives can be cited as organic compounds (main materials).

[0118] Specific examples of organic compounds (host materials) preferably used in combination with fluorescent luminescent materials include 9-phenyl-3-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviated as DPCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), 9,10-diphenylanthracene (abbreviated as DPANth), and N,N-diphenyl-9-[4-(10-phenyl-9-anthrayl]... [Phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthrayl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthrayl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviation: PCAPA), N-(9,10-diphenyl-2-anthrayl)-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylamine, N,N,N',N',N”,N”,N”',N”'-octaphenyldi Benzo[g,p]β-2,7,10,15-tetramine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthrayl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthrayl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthrayl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-en-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9 , 10-bis(3,5-diphenylphenyl)anthracene (abbreviated as DPPA), 9,10-bis(2-naphthyl)anthracene (abbreviated as DNA), 2-tert-butyl-9,10-bis(2-naphthyl)anthracene (abbreviated as t-BuDNA), 9,9'-bianthracene (abbreviated as BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviated as DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviated as DPNS2), 1,3,5-tris(1-pyrene)benzene (abbreviated as TPB3), 5,12-diphenyltetraphenyl, 5,12-bis(biphenyl-2-yl)tetraphenyl, etc.

[0119] <<Phosphorescent Host Material>> When the luminescent material used for the luminescent layers (113, 113a, 113b, 113c) is a phosphorescent luminescent material, the organic compound (host material) used in combination with the luminescent material should be an organic compound whose triple excitation energy (the energy difference between the ground state and the triple excited state) is greater than the triple excitation energy of the luminescent material. Note that when multiple organic compounds (e.g., a first host material and a second host material (or auxiliary material)) are used in combination with the luminescent material to form an excited-state complex, it is preferable to use these multiple organic compounds mixed with the phosphorescent luminescent material.

[0120] By employing such a structure, luminescence via ExTET (Exciplex-Triplet Energy Transfer), which utilizes energy transfer from excited-state complexes to luminescent materials, can be efficiently obtained. As a combination of multiple organic compounds, it is preferable to use a combination that readily forms excited-state complexes, and particularly preferably a combination of compounds that readily accept holes (hole-transporting materials) and compounds that readily accept electrons (electron-transporting materials).

[0121] Although some of the content is repeated with the specific examples above, from the viewpoint that it is better to use it in combination with luminescent materials (phosphorescent materials), the organic compounds (main materials, auxiliary materials) that can be cited are aromatic amines, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, zinc metal complexes and aluminum metal complexes, diazole derivatives, triazole derivatives, benzimidazole derivatives, quinoline derivatives, dibenzoquinoline derivatives, pyrimidine derivatives, triazine derivatives, pyridine derivatives, bipyridine derivatives, phenoline derivatives, etc.

[0122] Note that among the above-mentioned organic compounds, specific examples of aromatic amines and carbazole derivatives that are organic compounds with high hole transport properties can be given as materials that are the same as the specific examples of hole transport materials mentioned above, and these materials are preferably used as host materials.

[0123] In addition, as specific examples of dibenzothiophene derivatives and dibenzofuran derivatives of organic compounds with high hole transport properties among the above-mentioned organic compounds, 4-{3-[3-(9-phenyl-9H-en-9-yl)phenyl]phenyl}dibenzofuran (abbreviated as: mmDBFFLBi-II), 4,4',4”-(benzyl-1,3,5-triyl)tris(dibenzofuran) (abbreviated as: DBF3P-II), DBT3 P-II, 2,8-diphenyl-4-[4-(9-phenyl-9H-en-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), 4-[4-(9-phenyl-9H-en-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), 4-[3-(triphenyl-2-yl)phenyl]dibenzothiophene (abbreviated as mDBTPTp-II), etc., are preferred as host materials.

[0124] In the above, specific examples of metal complexes that are organic compounds (electron transport materials) with high electron transport properties can be given as follows: tris(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq), tris(4-methyl-8-hydroxyquinoline)aluminum(III) (abbreviated as Almq3), bis(10-hydroxybenzo[h]quinoline)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq); metal complexes having a quinoline skeleton or a benzoquinoline skeleton, etc., these materials are preferably used as host materials.

[0125] In addition, preferred host materials include bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ), which are metal complexes with benzothiazolyl ligands and thiazolyl ligands.

[0126] Furthermore, among the aforementioned organic compounds, specific examples of acediazole derivatives, triazole derivatives, benzimidazole derivatives, quinoline derivatives, dibenzoquinoline derivatives, and phenoline derivatives that are organic compounds (electron transport materials) with high electron transport properties include 2-(4-biphenyl)-5-(4-tertiary butylphenyl)-1,3,4-acediazole (abbreviated as: PBD), 1,3-bis[5-(p-tertiary butylphenyl)-1,3,4-acediazole-2-yl]benzene (abbreviated as: OXD-7), and 9-[4-(5-phenyl-1,3,4-acediazole-2-yl]benzene. [3-(4-Biphenyl)-4-phenyl-5-(4-tributylphenyl)-1,2,4-triazole (TAZ), 2,2',2”-(1,3,5-phenyltriyl)tris(1-phenyl-1H-benzimidazole) (TPBI), 2-[3-(dibenzothiophene-4-yl)phenyl]-1-phenyl-1H-benzimidazole (mDBTBIm-II), 4,4'-bis(5-methylbenzothiozol-2-yl)stilbene (BzOS), ruberin (Bphen) Copper Bath (BCP), 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenoline (NBphen), 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenoline] (mPPhen2P), 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (2mDBTBPDBq-II), 2-[3'-(9H- Carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,h]quinoline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviation: 6mDBTPDBq-II), etc., are preferred as host materials.

[0127] Furthermore, among the above, specific examples of heterocyclic compounds with a diazine skeleton, heterocyclic compounds with a triazine skeleton, and heterocyclic compounds with a pyridine skeleton that are organic compounds (electron transport materials) with high electron transport properties include 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothiophene)phenyl]pyrimidine (abbreviated as: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mCzP2Pm), 2 The following materials are preferred as host materials: 4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviated as mPCCzPTzn-02), 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy), and 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB).

[0128] In addition, as preferred host materials, poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylenyl-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), poly[(9,9-dioctylenyl-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) and other polymeric compounds can also be used.

[0129] Alternatively, bipolar organic compounds with high hole transport and high electron transport, such as 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviated as PCCzQz), can be used as the main material.

[0130] <Electron Transport Layer> The electron transport layers (114, 114a, 114b) are layers that transport electrons injected from the second electrode 102 and the charge generation layers (106, 106a, 106b) through the electron injection layers (115, 115a, 115b) described later to the light-emitting layers (113, 113a, 113b, 113c). Furthermore, the electron transport layers (114, 114a, 114b) are layers containing an electron transport material. Preferably, the electron transport material used for the electron transport layers (114, 114a, 114b) is a material having an electron mobility of 1×10⁻⁶ cm² / Vs or higher when the square root of the electric field strength [V / cm] is 600. In addition, any material other than the above-mentioned material can be used as long as its electron transportability is higher than its hole transportability. Furthermore, the electron transport layers (114, 114a, 114b) function even as a single layer, but when a stacked structure of two or more layers is used as required, the device characteristics can be improved.

[0131] <<Electron Transport Materials>> As electron transport materials that can be used in electron transport layers (114, 114a, 114b), organic compounds with a structure in which the furan ring and aromatic ring are fused together with a furan diazine skeleton, metal complexes with a quinoline skeleton, metal complexes with a benzoquinoline skeleton, metal complexes with a acetazole skeleton, metal complexes with a thiazole skeleton, etc., and materials with high electron transport properties such as acediazole derivatives, triazole derivatives, imidazole derivatives, acetazole derivatives, thiazole derivatives, phenoline derivatives, quinoline derivatives with quinoline ligands, benzoquinoline derivatives, quinoline derivatives, dibenzoquinoline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, nitrogen-containing heteroaromatic compounds, etc., can also be used.

[0132] Specific examples of electron transport materials include: 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviation: 2mDBTBPDBq-II), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indo[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophene-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 4 ... [Thiophen-4-yl)phenyl]-8-(naphthyl-2-yl)-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofurano[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 9-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]naphthyl[1',2':4,5]furano[2,3-b]pyrazine (Abbreviation: 9mDBtBPNfpr), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl-3-yl)]naphtho[1',2':4,5]furano[3,2-d]pyrimidine (Abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthyl)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (Abbreviation: 8(βN2)-4mDBtPBfpm), 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine Metal complexes with quinoline or benzoquinoline skeletons, such as bis(8BP-4mDBtPBfpm), tri(8-hydroxyquinoline)aluminum(III) (abbreviated as Alq3), Almq3, BeBq2, bis(2-methyl-8-hydroxyquinoline)(4-phenylphenol)aluminum(III) (abbreviated as BAlq), and bis(8-hydroxyquinoline)zinc(II) (abbreviated as Znq); and metal complexes with acetazole or thiazole skeletons, such as bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenol]zinc(II) (abbreviated as ZnBTZ).

[0133] Furthermore, in addition to metal complexes, acediazole derivatives such as PBD, OXD-7, and CO11 can also be used as electron transport materials; triazole derivatives such as TAZ and p-EtTAZ; imidazole derivatives (including benzimidazole derivatives) such as TPBI and mDBTBIm-II; acediazole derivatives such as BzOS; phen, BCP, NBphen, and mPPhen2P phendiazole derivatives; 2mDBTPDBq-II and 2mDBT... Quinoline derivatives or dibenzoquinoline derivatives such as BPDBq-II, 2mCzBPDBq, 2CzPDBq-III, 7mDBTPDBq-II, and 6mDBTPDBq-II; pyridine derivatives such as 35DCzPPy and TmPyPB; pyrimidine derivatives such as 4,6mPnP2Pm, 4,6mDBTP2Pm-II, and 4,6mCzP2Pm; and triazine derivatives such as PCCzPTzn and mPCCzPTzn-02.

[0134] In addition, as electron transport materials, polymers such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfuran-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfuran-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used.

[0135] In addition, the electron transport layer (114, 114a, 114b) can be a single layer or a stack of two or more layers containing the above-mentioned substances.

[0136] <Electron Injection Layer> The electron injection layer (115, 115a, 115b) is a layer containing a material with high electron injection capability. The electron injection layer (115, 115a, 115b) is a layer used to improve the efficiency of electron injection from the second electrode 102, and preferably uses a material whose work function value for the material used in the second electrode 102 is small (less than 0.5 eV) compared to the LUMO energy level value of the material used in the electron injection layer (115, 115a, 115b). Therefore, as electron injection layers (115, 115a, 115b), alkali metals, alkaline earth metals, or compounds thereof, such as lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), lithium 8-(hydroxyoxoline) (Liq), lithium 2-(2-pyridyl)phenol (LiPP), lithium 2-(2-pyridyl)-3-hydroxypyridine (LiPPy), lithium 4-phenyl-2-(2-pyridyl)phenol (LiPPP), lithium oxide (LiOx), and cesium carbonate, can be used. Additionally, rare earth metal compounds such as erbium fluoride (ErF3) can be used. Furthermore, electron compounds can also be used in the electron injection layers (115, 115a, 115b). Examples of electron compounds include mixed oxides of calcium and aluminum to which electrons are added at high concentrations. Alternatively, the materials constituting the electron transport layers (114, 114a, 114b) as described above can also be used.

[0137] Furthermore, a composite material formed by mixing an organic compound with an electron donor (donor) can also be used in the electron injection layer (115, 115a, 115b). This composite material exhibits excellent electron injection and electron transport properties because electrons are generated in the organic compound through the electron donor. In this case, the organic compound is preferably a material with excellent performance in transporting the generated electrons. Specifically, for example, an electron transport material (metal complex, heteroaromatic compound, etc.) used in the electron transport layer (114, 114a, 114b) as described above can be used. As the electron donor, any substance that provides electrons to the organic compound is acceptable. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Additionally, alkali metal oxides and alkaline earth metal oxides are preferred, such as lithium oxide, calcium oxide, and barium oxide. Furthermore, Lewisite such as magnesium oxide can also be used. Additionally, organic compounds such as tetrathiofulvalene (TTF) can also be used.

[0138] In addition, composite materials made of mixed organic compounds and metals can also be used for the electron injection layers (115, 115a, 115b). Note that the organic compounds used here are preferably those with a LUMO (Lowest Unoccupied Molecular Orbital) energy level of -3.6 eV or higher and -2.3 eV or lower. Furthermore, non-shared electron pairs are preferred.

[0139] Therefore, as the above-mentioned organic compound, it is preferable to use a material that includes heterocyclic compounds having non-shared electron pairs, such as those having a pyridine skeleton, a diazine skeleton (pyrimidine, pyrazine, etc.) or a triazine skeleton.

[0140] Note that examples of heterocyclic compounds with a pyridine skeleton include 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tris[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), copper bath (abbreviation: BCP), 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen), 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenanthroline] (abbreviation: mPPhen2P), and rubrogenthroline (abbreviation: Bphen).

[0141] Examples of heterocyclic compounds with a diazine skeleton include 2-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviated as: 2mDBTPDBq-II), 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviated as: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviated as: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoline (abbreviated as: 2CzPDBq-Ⅲ), and 7-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline. The following are examples of benzo[f,h]quinoline (abbreviated as: 7mDBTPDBq-II), 6-[3-(dibenzothiophene-4-yl)phenyl]dibenzo[f,h]quinoline (abbreviated as: 6mDBTPDBq-II), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothiophene)phenyl]pyrimidine (abbreviated as: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviated as: 4,6mCzP2Pm), 4-{3-[3'-(9H-carbazole-9-yl)]biphenyl-3-yl}benzofuran[3,2-d]pyrimidine (abbreviated as: 4mCzBPBfpm), etc.

[0142] Examples of heterocyclic compounds with a triazine skeleton include 2-{4-[3-(N-phenyl-9H-carbazo-3-yl)-9H-carbazo-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), 2,4,6-tris[3'-(pyridin-3-yl)biphenyl-3-yl]-1,3,5-triazine (abbreviated as TmPPPyTz), and 2,4,6-tris(2-pyridinyl)-1,3,5-triazine (abbreviated as 2Py3Tz).

[0143] As the metal, it is preferable to use a transition metal belonging to Group 5, Group 7, Group 9 or Group 11 of the periodic table and a material belonging to Group 13, for example, Ag, Cu, Al or In. In addition, at this time, a single occupied orbital (SOMO) is formed between the organic compound and the transition metal.

[0144] Furthermore, for example, when amplifying the light received from the light-emitting layer 113b, it is preferable to form the light so that the optical distance between the second electrode 102 and the light-emitting layer 113b is less than 1 / 4 of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, the optical distance can be adjusted by changing the thickness of the electron transport layer 114b or the electron injection layer 115b.

[0145] Furthermore, as shown in FIG2D, by providing a charge generation layer 106 between two EL layers (103a, 103b), a structure in which multiple EL layers are stacked between a pair of electrodes can be formed (also known as a series structure).

[0146] <Charge Generation Layer> The charge generation layer 106 has the function of injecting electrons into the EL layer 103a and holes into the EL layer 103b when a voltage is applied between the first electrode 101 (anode) and the second electrode 102 (cathode). The charge generation layer 106 may have a structure that adds an electron acceptor (acceptor) to the hole transport material (also called a P-type layer), or a structure that adds an electron donor (donor) to the electron transport material (also called an electron injection buffer layer). Alternatively, both of these structures may be stacked. Furthermore, an electron relay layer may be provided between the P-type layer and the electron injection buffer layer. Note that by using the above-described materials to form the charge generation layer 106, the rise in driving voltage caused by the stacking of EL layers can be suppressed.

[0147] When the charge generation layer 106 has a structure (P-type layer) that adds an electron acceptor to the hole transport material of the organic compound, the material shown in this embodiment can be used as the hole transport material. Examples of electron acceptors include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinone dimethane (abbreviated as F4-TCNQ) and chloroquinone. Furthermore, oxides of metals belonging to Groups 4 to 8 of the periodic table can be used. Specifically, examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide. The aforementioned acceptor materials can also be used. Additionally, the P-type layer can be a hybrid film formed by mixing a hole transport material and an electron acceptor, or a laminated film containing a hole transport material and an electron acceptor.

[0148] When the charge generation layer 106 has a structure (electron injection buffer layer) for adding an electron donor to the electron transport material, the material shown in this embodiment can be used as the electron transport material. Furthermore, alkali metals, alkaline earth metals, rare earth metals, or metals belonging to Groups 2 and 13 of the periodic table, and their oxides or carbonates, can be used as electron donors. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide (Li₂O), cesium carbonate, etc., are preferred. In addition, organic compounds such as tetrathianaphthacene can also be used as electron donors.

[0149] In the charge generation layer 106, when an electron relay layer is provided between the P-type layer and the electron injection buffer layer, the electron relay layer at least contains a material with electron transport properties and has the function of smoothly transferring electrons while preventing the interaction between the electron injection buffer layer and the P-type layer. Preferably, the LUMO energy level of the electron transport material contained in the electron relay layer is between the LUMO energy level of the acceptor material in the P-type layer and the LUMO energy level of the electron transport material contained in the electron transport layer in contact with the charge generation layer 106. Specifically, the LUMO energy level of the electron transport material in the electron relay layer is preferably -5.0 eV or higher, more preferably -5.0 eV or higher and -3.0 eV or lower. Furthermore, the electron transport material in the electron relay layer is preferably a phthalocyanine-based material or a metal complex having metal-oxygen bonds and aromatic ligands.

[0150] Although Figure 2D shows a structure with two stacked EL layers 103, it can be made into a stacked structure with more than three layers by setting a charge generation layer between different EL layers.

[0151] <Substrate> The light-emitting device shown in this embodiment can be formed on various substrates. Note that there is no specific limitation on the type of substrate. Examples of such substrates include semiconductor substrates (e.g., single-crystal substrates or silicon substrates), SOI substrates, glass substrates, quartz substrates, plastic substrates, metal substrates, stainless steel substrates, substrates containing stainless steel foil, tungsten substrates, substrates containing tungsten foil, flexible substrates, laminated films, paper or substrate films containing fibrous materials, etc.

[0152] Examples of glass substrates include barium borosilicate glass, aluminum borosilicate glass, and soda-lime glass. Examples of flexible substrates, laminating films, and substrate films include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyether ether (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aromatic polyamide, epoxy, inorganic vapor-deposited films, and paper.

[0153] In addition, when manufacturing the light-emitting device shown in this embodiment, vacuum processes such as vapor deposition, spin coating, and inkjet printing can be used. As vapor deposition methods, physical vapor deposition methods (PVD methods) such as sputtering, ion plating, ion beam vapor deposition, molecular beam vapor deposition, and vacuum vapor deposition, as well as chemical vapor deposition methods (CVD methods) can be used. In particular, functional layers (hole injection layers (111, 111a, 111b), hole transport layers (112, 112a, 112b), light-emitting layers (113, 113a, 113b, 113c), electron transport layers (114, 114a, 114b), electron injection layers (115, 115a, 115b)) and charge generation layers (106, 106a, 106b)) included in the EL layer of the light-emitting device can be formed using methods such as vapor deposition (vacuum vapor deposition), coating (dip coating, dye coating, rod coating, spin coating, spray coating, etc.), and printing (inkjet printing, screen printing, offset printing, flexographic printing, photogravure printing, micro-contact printing, etc.).

[0154] Note that when using the film-forming methods such as coating and printing described above, high molecular weight compounds (oligomers, dendritic polymers, polymers, etc.), medium molecular weight compounds (compounds between low and high molecular weight: molecular weight 400 or higher and 4000 or lower), and inorganic compounds (quantum dot materials, etc.) can be used. Note that as quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell quantum dot materials, and core-type quantum dot materials can be used.

[0155] The materials of each functional layer (hole injection layer (111, 111a, 111b), hole transport layer (112, 112a, 112b), light emission layer (113, 113a, 113b, 113c), electron transport layer (114, 114a, 114b), electron injection layer (115, 115a, 115b)) and charge generation layer (106, 106a, 106b)) constituting the EL layer (103, 103a, 103b) of the light-emitting device shown in this embodiment are not limited to the materials shown in this embodiment. Any materials that can satisfy the functions of each layer can be used in combination.

[0156] The structure shown in this embodiment can be used in combination with the structures shown in other embodiments as appropriate.

[0157] Embodiment 2 In this embodiment, a specific structural example and manufacturing method of a light-emitting device (also called a display panel) according to an embodiment of the present invention will be described.

[0158] <Structural Example 1 of Light-Emitting Device 700> The light-emitting device 700 shown in FIG3A includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. Furthermore, light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 disposed on a first substrate 510. The functional layer 520 includes, in addition to driving circuits GD and SD composed of multiple transistors, pixel circuits, etc., wiring that electrically connects them. Note that these driving circuits are electrically connected to light-emitting devices 550B, 550G, and 550R, and can drive these devices. Furthermore, the light-emitting device 700 includes an insulating layer 705 on the functional layer 520 and each light-emitting device, and the insulating layer 705 has the function of bonding the second substrate 770 and the functional layer 520. Furthermore, driving circuits GD and SD are described in Embodiment 3.

[0159] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 1. In particular, the different cases of the EL layer 103 in the structure shown in FIG2A are shown in each light-emitting device.

[0160] The light-emitting device 550B includes an electrode 551B, an electrode 552, an EL layer 103B, and an insulating layer 107B. Note that the specific structure of each layer is as shown in Embodiment 1. Furthermore, the EL layer 103B has a stacked structure composed of multiple layers with different functions, including a light-emitting layer. In FIG3A, only the hole injection / transport layer 104B, the light-emitting layer 113B, the electron transport layer 108B, and the electron injection layer 109 are shown among the layers included in the EL layer 103B, but the present invention is not limited thereto. Note that the hole injection / transport layer 104B shows a layer including the functions of the hole injection layer and the hole transport layer shown in Embodiment 1, and may also have a stacked structure. Note that in this specification, the hole injection / transport layer can be referred to as a layer as described above in any light-emitting device. Furthermore, the electron transport layer 108B may also have a stacked structure and may also include a hole barrier layer for blocking holes moving from the anode side through the light-emitting layer to the cathode side in a manner that contacts the light-emitting layer 113B. The electron injection layer 109 may also have a stacked structure, which may be partially or entirely formed using different materials.

[0161] As shown in FIG. 3A, the insulating layer 107B is formed on the electrode 551B with photoresist remaining on a portion of the EL layer 103B (in this embodiment, the electron transport layer 108B is formed on the light-emitting layer 113B). Therefore, the insulating layer 107B is formed in contact with the side (or end) of the portion of the EL layer 103B (described above). This suppresses the entry of oxygen, moisture, or their constituent elements from the side of the EL layer 103B into the interior. Note that the insulating layer 107B can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. The insulating layer 107B can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method, which has good coverage.

[0162] An electron injection layer 109 is formed by a layer covering a portion of the EL layer 103B (an electron transport layer 108B formed on the light-emitting layer 113B) and an insulating layer 107B. Note that the electron injection layer 109 is preferably a stacked structure with two or more layers having different resistances in the layers. For example, it may also have a structure with a first layer formed using only an electron transport material that contacts the electron transport layer 108B and a second layer formed using an electron transport material containing a metallic material thereon, or a structure that also includes a third layer formed using an electron transport material containing a metallic material between the first layer and the electron transport layer 108B.

[0163] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551B and 552 have overlapping areas. Furthermore, an EL layer 103B is included between electrodes 551B and 552. Thus, electron injection layer 109 is located on the side (or end) of a portion of EL layer 103B across insulating layer 107B, or electrode 552 is located on the side (or end) of a portion of EL layer 103B across electron injection layer 109 and insulating layer 107B. This prevents short circuits between EL layer 103B and electrode 552, and more specifically, between the hole injection / transport layer 104B included in EL layer 103B and electrode 552.

[0164] The EL layer 103B shown in FIG3A has the same structure as the EL layers 103, 103a, 103b and 103c described in Embodiment 1. In addition, the EL layer 103B can emit blue light, for example.

[0165] The light-emitting device 550G includes an electrode 551G, an electrode 552, an EL layer 103G, and an insulating layer 107G. Note that the specific structure of each layer is as shown in Embodiment 1. Furthermore, the EL layer 103G has a stacked structure composed of multiple layers with different functions, including a light-emitting layer. In FIG3A, only the hole injection / transport layer 104G, the light-emitting layer 113G, the electron transport layer 108G, and the electron injection layer 109 are shown among the layers included in the EL layer 103G, but the present invention is not limited thereto. Note that the hole injection / transport layer 104G shows a layer including the functions of the hole injection layer and the hole transport layer shown in Embodiment 1, and may also have a stacked structure.

[0166] Furthermore, the electron transport layer 108G may have a stacked structure, and may also include a hole barrier layer in a manner that contacts the light-emitting layer 113G to block holes from moving from the anode side through the light-emitting layer 113G to the cathode side. The electron injection layer 109 may also have a stacked structure, part or all of which may be formed using different materials.

[0167] As shown in FIG. 3A, the insulating layer 107G is formed on the electrode 551G with photoresist remaining on a layer formed on a portion of the EL layer 103G (in this embodiment, the electron transport layer 108G is formed on the light-emitting layer 113G). Therefore, the insulating layer 107G is formed in contact with the side (or end) of the layer (described above) of a portion of the EL layer 103G. This suppresses the entry of oxygen, moisture, or their constituent elements from the side of the EL layer 103G into the interior. Note that the insulating layer 107G can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. The insulating layer 107G can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method, which has good coverage.

[0168] An electron injection layer 109 is formed by a layer covering a portion of the EL layer 103G (an electron transport layer 108G formed on the light-emitting layer 113G) and an insulating layer 107G. Note that the electron injection layer 109 is preferably a stacked structure with two or more layers having different resistances in the layers. For example, it may also have a structure with a first layer formed using only an electron transport material in contact with the electron transport layer 108G and a second layer formed using an electron transport material containing a metallic material thereon, or a structure that also includes a third layer formed using an electron transport material containing a metallic material between the first layer and the electron transport layer 108G.

[0169] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551G and 552 have overlapping areas. Furthermore, an EL layer 103G is included between electrodes 551G and 552. Thus, electron injection layer 109 is located on the side (or end) of a portion of EL layer 103G across insulating layer 107G, or electrode 552 is located on the side (or end) of a portion of EL layer 103G across electron injection layer 109 and insulating layer 107G. This prevents short circuits between EL layer 103G and electrode 552, and more specifically, between the hole injection / transport layer 104G included in EL layer 103G and electrode 552.

[0170] The EL layer 103G shown in FIG3A has the same structure as the EL layers 103, 103a, 103b and 103c described in Embodiment 1. In addition, the EL layer 103G can emit green light, for example.

[0171] The light-emitting device 550R includes an electrode 551R, an electrode 552, an EL layer 103R, and an insulating layer 107R. Note that the specific structure of each layer is as shown in Embodiment 1. Furthermore, the EL layer 103R has a stacked structure composed of multiple layers with different functions, including a light-emitting layer. In FIG3A, only the hole injection / transport layer 104R, the light-emitting layer 113R, the electron transport layer 108R, and the electron injection layer 109 are shown among the layers included in the EL layer 103R, but the present invention is not limited thereto. Note that the hole injection / transport layer 104R shows a layer including the functions of the hole injection layer and the hole transport layer shown in Embodiment 1, and may also have a stacked structure. Note that in this specification, the hole injection / transport layer can be referred to as a layer as described above in any light-emitting device. Furthermore, the electron transport layer 108R may also have a stacked structure and may also include a hole barrier layer for blocking holes moving from the anode side through the light-emitting layer to the cathode side in a manner that contacts the light-emitting layer. The electron injection layer 109 may also have a stacked structure, which may be partially or entirely formed using different materials.

[0172] As shown in FIG3A, the insulating layer 107R is formed on the electrode 551R with photoresist remaining on a layer formed on a portion of the EL layer 103R (in this embodiment, the electron transport layer 108R is formed on the light-emitting layer 113R). Therefore, the insulating layer 107R is formed in contact with the side (or end) of the layer (described above) of a portion of the EL layer 103R. This suppresses the entry of oxygen, moisture, or their constituent elements from the side of the EL layer 103R into the interior. Note that the insulating layer 107R can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. The insulating layer 107R can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method, which has good coverage.

[0173] An electron injection layer 109 is formed by a layer covering a portion of the EL layer 103R (an electron transport layer 108R formed on the light-emitting layer 113R) and an insulating layer 107R. Note that the electron injection layer 109 is preferably a stacked structure with two or more layers having different resistances in the layers. For example, it may also have a structure with a first layer formed using only an electron transport material that contacts the electron transport layer 108R and a second layer formed using an electron transport material containing a metallic material thereon, or a structure that further includes a third layer formed using an electron transport material containing a metallic material between the first layer and the electron transport layer 108R.

[0174] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551R and 552 have overlapping areas. Furthermore, an EL layer 103R is included between electrodes 551R and 552. Thus, electron injection layer 109 is located on the side (or end) of a portion of EL layer 103R across insulating layer 107R, or electrode 552 is located on the side (or end) of a portion of EL layer 103R across electron injection layer 109 and insulating layer 107R. This prevents short circuit between EL layer 103R and electrode 552, and more specifically, prevents short circuit between the hole injection / transport layer 104R included in EL layer 103R and electrode 552.

[0175] The EL layer 103R shown in FIG3A has the same structure as the EL layers 103, 103a, 103b and 103c described in Embodiment 1. In addition, the EL layer 103R can emit red light, for example.

[0176] Gap 580 is included between EL layers 103B, EL layers 103G, and EL layers 103R. In each EL layer, since the conductivity of the hole injection layer, especially the hole transport region located between the anode and the light-emitting layer, is high in many cases, crosstalk sometimes occurs when the hole injection layer is formed as a layer shared in adjacent light-emitting devices. Therefore, as shown in this structural example, by providing gap 580 between each EL layer, crosstalk occurring between adjacent light-emitting devices can be suppressed.

[0177] In high-definition light-emitting devices (display panels) with a resolution exceeding 1000 ppi, crosstalk occurs when electrical conduction occurs between EL layers 103B, EL layers 103G, and EL layers 103R, thus narrowing the color gamut that the light-emitting device can display. By setting a gap 580 in high-definition display panels with a resolution exceeding 1000 ppi, preferably high-definition display panels with a resolution exceeding 2000 ppi, and more preferably ultra-high-definition display panels with a resolution exceeding 5000 ppi, a display panel capable of displaying vibrant colors can be provided.

[0178] Figure 3B is a top view of the light-emitting device shown in Figure 3A in the XY direction, and the cross-sectional view along line Y1-Y2 is equivalent to Figure 3A. As shown in Figure 3B, the partition wall 528 includes an opening 528B, an opening 528G, and an opening 528R. Note that, as shown in Figure 3A, the opening 528B overlaps with the electrode 551B, the opening 528G overlaps with the electrode 551G, and the opening 528R overlaps with the electrode 551R.

[0179] Note that since photolithography is used to form patterns in the separation process of these EL layers (EL layer 103B, EL layer 103G, and EL layer 103R), high-definition light-emitting devices (display panels) can be manufactured. Furthermore, the ends (side surfaces) of the EL layers (hole injection / transport layer, light-emitting layer, and electron transport layer) processed by photolithography have a shape with approximately the same surface (or, located on approximately the same plane). Additionally, the gap 580 between each EL layer is preferably 5 μm or less, more preferably 1 μm or less.

[0180] In the EL layer, since the conductivity of the hole injection layer, especially in the hole transport region located between the anode and the light-emitting layer, is high in many cases, crosstalk sometimes occurs when the hole injection layer is formed as a layer shared by adjacent light-emitting devices. Therefore, as shown in this structural example, crosstalk occurring between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layer.

[0181] <Example 1 of manufacturing method of light-emitting device> As shown in FIG4A, electrodes 551B, 551G and 551R are formed. For example, a conductive film is formed on the functional layer 520 formed on the first substrate 510, and the conductive film is processed into a specified shape by photolithography.

[0182] Note that conductive films can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD). CVD methods include plasma-enhanced chemical vapor deposition (PECVD) and thermal CVD. Additionally, metal-organic chemical vapor deposition (MOCVD) is one example of a thermal CVD method.

[0183] In addition to the photolithography method mentioned above, conductive films can also be processed using nanoimprinting, sandblasting, and peeling methods. Furthermore, island-shaped films can be directly formed using shadow masking methods such as metal masks.

[0184] There are typically two processing methods using photolithography. One method involves forming a photoresist mask on the film to be processed, processing the film by etching or the like, and then removing the photoresist mask. The other method involves forming a photosensitive film, and then exposing and developing it to process the film into the desired shape.

[0185] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365nm), g-line (wavelength 436nm), h-line (wavelength 405nm), or a mixture of these. Additionally, ultraviolet light, KrF laser, or ArF laser can also be used. Furthermore, immersion exposure can also be used. Additionally, extreme ultraviolet (EUV) light or X-rays can be used as the light for exposure. Furthermore, an electron beam can be used instead of the light used for exposure. When using extreme ultraviolet light, X-rays, or an electron beam, extremely fine processing can be performed, making it preferable. Note that when exposure is performed by scanning with a beam such as an electron beam, a photomask is not required.

[0186] As a thin film etching using a photoresist mask, dry etching, wet etching, sandblasting, etc. can be used.

[0187] Next, as shown in FIG4B, partition walls 528 are formed between electrodes 551B, 551G, and 551R. For example, an insulating film is formed covering electrodes 551B, 551G, and 551R, and an opening is formed using photolithography to expose a portion of electrodes 551B, 551G, and 551R, thereby forming partition walls 528. Note that inorganic materials, organic materials, or composite materials of inorganic and organic materials can be used as materials for partition walls 528. Specifically, inorganic oxide films, inorganic nitride films, or inorganic oxynitride films, or laminates of multiple films selected from the above, can be used. More specifically, silicon oxide films, films containing acrylic resin, or films containing polyimide, or laminates of multiple films selected from the above, can be used.

[0188] Next, as shown in FIG5A, a hole injection / transport layer 104B, a light-emitting layer 113B, and an electron transport layer 108B are formed on electrodes 551B, 551G, 551R, and the partition wall 528. For example, the hole injection / transport layer 104B, the light-emitting layer 113B, and the electron transport layer 108B are formed on electrodes 551B, 551G, 551R, and the partition wall 528 in a manner that covers them.

[0189] Next, as shown in FIG5B, the hole injection / transport layer 104B, the light-emitting layer 113B, and the electron transport layer 108B on electrode 551B are processed into a predetermined shape. For example, photoresist is formed using photolithography, and the hole injection / transport layer 104B, the light-emitting layer 113B, and the electron transport layer 108B on electrode 551G and the hole injection / transport layer 104B, the light-emitting layer 113B, and the electron transport layer 108B on electrode 551R are removed by etching, processed into a shape with sides (or exposed sides), in other words, processed into a strip shape extending in the direction intersecting the paper plane of the drawing (X-axis direction). Specifically, dry etching is performed using photoresist REG formed on the hole injection / transport layer 104B, the light-emitting layer 113B, and the electron transport layer 108B overlapping with electrode 551B (see FIG5B). Note that the partition wall 528 can be used as an etching stop layer.

[0190] Next, as shown in FIG5C, with the photoresist REG formed, a hole injection / transport layer 104G, a light-emitting layer 113G, and an electron transport layer 108G are formed on the photoresist REG, electrode 551G, electrode 551R, and separator 528. For example, the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer 108G are formed on the electrode 551G, electrode 551R, and separator 528 in a manner that covers them, using a vacuum evaporation method.

[0191] Next, as shown in FIG6A, the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer 108G on electrode 551G are processed into a predetermined shape. For example, photoresist is formed on the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer 108G on electrode 551G using photolithography, and the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer 108G on electrode 551B and the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer 108G on electrode 551R are removed by etching, and processed into a shape with sides (or exposed sides), in other words, processed into a strip shape extending in the direction (X-axis direction) intersecting the paper plane of the drawing. Specifically, dry etching is performed using photoresist REG formed on the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer 108G overlapping with electrode 551G. Note that the separator 528 can be used as an etch stop layer.

[0192] Next, as shown in FIG6B, with photoresist REG formed on electrodes 551B and 551G, a hole injection / transport layer 104R, a light-emitting layer 113R, and an electron transport layer 108R are formed on photoresist REG, electrode 551R, and separator 528. For example, the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R are formed on electrode 551R, photoresist REG, and separator 528 in a manner that covers them, using a vacuum evaporation method.

[0193] Next, as shown in FIG6C, the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R on electrode 551R are processed into a predetermined shape. For example, photoresist is formed on the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R on electrode 551R using photolithography, and the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R on electrode 551B and the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R on electrode 551G are removed by etching, and the shape is processed into a shape with sides (or exposed sides), in other words, processed into a strip shape extending in the direction (X-axis direction) intersecting the paper plane of the drawing. Specifically, dry etching is performed using photoresist REG formed on the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R overlapping with electrode 551R. Note that the separator 528 can be used as an etch stop layer.

[0194] Note that, as shown in Figures 5A, 5B, 5C, 6A, 6B and 6C, preferably, a hole injection / transport layer 104B, a light-emitting layer 113B and an electron transport layer 108B are initially formed on electrode 551B, followed by a hole injection / transport layer 104G, a light-emitting layer 113G and an electron transport layer 108G being formed on electrode 551G, and finally a hole injection / transport layer 104R, a light-emitting layer 113R and an electron transport layer 108R being formed on electrode 551R.

[0195] In the above process, when the hole injection / transport layer 104B, light-emitting layer 113B, and electron transport layer 108B on electrode 551G and the hole injection / transport layer 104B, light-emitting layer 113B, and electron transport layer 108B on electrode 551R are removed by etching, the surfaces of electrodes 551G and 551R are exposed to etching gas. Furthermore, when the hole injection / transport layer 104G, light-emitting layer 113G, and electron transport layer 108G on electrode 551R are removed by etching, the surface of electrode 551R is exposed to etching gas. Therefore, the surface of electrode 551B is not exposed to etching gas, but the surface of electrode 551G is exposed to etching gas once, and the surface of electrode 551R is exposed to etching gas twice.

[0196] The surface of the electrode is exposed to etching gas, which sometimes damages the electrode surface. Furthermore, using an electrode with a damaged surface to form a light-emitting device sometimes degrades the characteristics of the light-emitting device. Note that the degree to which the surface condition of the electrode affects the characteristics of the light-emitting device depends on the structure of the light-emitting device, the materials used, etc. When comparing light-emitting devices 550B, 550G, and 550R, light-emitting device 550B is most affected by the surface condition of the electrode.

[0197] At this time, by initially forming the hole injection / transport layer 104B, the light-emitting layer 113B and the electron transport layer 108B on the electrode 551B, the surface of the electrode 551B can be prevented from being exposed to the etching gas and the characteristics of the light-emitting device 550B, which is most affected by the surface state of the electrode, can be prevented from deteriorating.

[0198] Next, an insulating layer 107 is formed on the photoresist REG, the hole injection / transport layer 104B, the light-emitting layer 113B, the electron transport layer 108B, the hole injection / transport layer 104G, the light-emitting layer 113G, the electron transport layer 108G, the hole injection / transport layer 104R, the light-emitting layer 113R, the electron transport layer 108R, and the partition wall 528. For example, the insulating layer 107 is formed on the photoresist REG, the hole injection / transport layer 104B, the light-emitting layer 113B, the electron transport layer 108B, the hole injection / transport layer 104G, the light-emitting layer 113G, the electron transport layer 108G, the hole injection / transport layer 104R, the light-emitting layer 113R, the electron transport layer 108R, and the partition wall 528 in a manner that covers them. At this point, as shown in FIG6C, the insulating layer 107 is formed in contact with the sides of the hole injection / transport layer 104B, the light-emitting layer 113B, the electron transport layer 108B, the hole injection / transport layer 104G, the light-emitting layer 113G, the electron transport layer 108G, the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R. This prevents oxygen, moisture, or their constituent elements from entering the interior from the sides of the hole injection / transport layer 104B, the light-emitting layer 113B, the electron transport layer 108B, the hole injection / transport layer 104G, the light-emitting layer 113G, the electron transport layer 108G, the hole injection / transport layer 104R, the light-emitting layer 113R, and the electron transport layer 108R. Note that materials used for the insulating layer 107 can include, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride.

[0199] Next, as shown in FIG7A, the photoresist REG is removed to form an electron injection layer 109 on the insulating layers (107B, 107G, 107R) and the electron transport layers (108B, 108G, 108R). The electron injection layer 109 is formed, for example, by vacuum evaporation. Note that the electron injection layer 109 is located on the side of a portion of each EL layer (103B, 103G, 103R) across the insulating layers (107B, 107G, 107R) (note that this includes the hole injection / transport layers (104R, 104G, 104B), the light-emitting layers (113B, 113G, 113R), and the electron transport layers (108B, 108G, 108R)).

[0200] Next, as shown in FIG7B, electrode 552 is formed. Electrode 552 is formed, for example, by vacuum evaporation. Note that electrode 552 is formed on electron injection layer 109. Note that electrode 552 is located on the side (or end) of a portion of each EL layer (103B, 103G, 103R) across electron injection layer 109 and insulating layers (107B, 107G, 107R) (note that this includes hole injection / transport layers (104R, 104G, 104B), light-emitting layers (113B, 113G, 113R), and electron transport layers (108B, 108G, 108R)). This prevents short circuits between each EL layer (103B, 103G, 103R) and electrode 552, and more specifically, between the hole injection / transport layers (104B, 104G, 104R) included in each EL layer (103B, 103G, 103R) and electrode 552.

[0201] Through the above process, the EL layers 103B, EL layers 103G and EL layers 103R in the light-emitting devices 550B, 550G and 550R can be separated and processed.

[0202] Note that since photolithography is used to form patterns in the separation process of these EL layers (EL layer 103B, EL layer 103G, and EL layer 103R), high-definition light-emitting devices (display panels) can be manufactured. Furthermore, the ends (sides) of the EL layers (hole injection / transport layer, light-emitting layer, and electron transport layer) processed by photolithography have a shape that is substantially the same surface (or located on substantially the same plane).

[0203] In the EL layer, since the conductivity of the hole injection layer, especially in the hole transport region located between the anode and the light-emitting layer, is high in many cases, crosstalk sometimes occurs when the hole injection layer is formed as a layer shared by adjacent light-emitting devices. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layer.

[0204] <Example 2 of the structure of the light-emitting device 700> The light-emitting device 700 shown in FIG8 includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. Furthermore, light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 disposed on a first substrate 510. The functional layer 520 includes, in addition to driving circuits GD and SD composed of multiple transistors, wiring that electrically connects them. Note that these driving circuits are electrically connected to the light-emitting devices 550B, 550G, and 550R, and can drive these devices.

[0205] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 1. In particular, the different cases of the EL layer 103 in the structure shown in FIG2A are shown in each light-emitting device.

[0206] Note that the specific structure of each light-emitting device shown in Figure 8 is the same as that of light-emitting devices 550B, 550G and 550R described in Figures 3A and 3B.

[0207] As shown in Figure 8, the hole injection / transmission layer (104B, 104G, 104R) included in the EL layer (103B, 103G, 103R) of each light-emitting device (550B, 550G, 550R) is smaller than the other functional layers constituting the EL layer (103B, 103G, 103R) and is covered by the stacked functional layers.

[0208] Note that in this structure, each of the hole injection / transmission layers (104B, 104G, 104R) in each EL layer is completely separated by other functional layers, so there is no need to provide the insulating layer 107 shown in the structural example 1 (see Figure 3A) to prevent short circuit with electrode 552.

[0209] Furthermore, since each EL layer (EL layer 103B, EL layer 103G and EL layer 103R) of this structure is patterned using photolithography during the separation process, the ends (sides) of the processed EL layers (light-emitting layer and electron transport layer) become shapes with approximately the same surface (or located on approximately the same plane).

[0210] In the EL layer, since the conductivity of the hole injection layer, especially in the hole transport region located between the anode and the light-emitting layer, is high in many cases, crosstalk sometimes occurs when the hole injection layer is formed as a layer shared by adjacent light-emitting devices. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layer.

[0211] In this specification, etc., devices manufactured using a metal mask or FMM (Fine Metal Mask) are sometimes referred to as MM (Metal Mask) structure devices. Furthermore, in this specification, devices manufactured without a metal mask or FMM are referred to as MML (Metal Mask Less) structure devices.

[0212] Furthermore, in this specification, the structure in which light-emitting devices of each color (here, blue (B), green (G), and red (R)) are separately formed or coated with light-emitting layers is sometimes referred to as an SBS (Side By Side) structure. Additionally, in this specification, a light-emitting device capable of emitting white light is sometimes referred to as a white light-emitting device. A white light-emitting device, combined with a color layer (e.g., a color filter), can realize a display device that displays in full color.

[0213] Furthermore, light-emitting devices can be broadly classified into single-structure and series-structure devices. A preferred single-structure device has the following structure: an EL layer is included between a pair of electrodes, and this EL layer includes one or more light-emitting layers. To obtain white light emission, the light-emitting layers are selected such that the light emission of each of the two or more light-emitting layers is in a complementary color relationship. For example, by making the light emission color of the first light-emitting layer complementary to the light emission color of the second light-emitting layer, a structure in which the light-emitting device as a whole emits white light can be obtained. The same applies to light-emitting devices including three or more light-emitting layers.

[0214] The series-connected device preferably has the following structure: two or more EL layers are included between a pair of electrodes, and each EL layer includes one or more light-emitting layers. To obtain white light emission, a structure is used to combine the light emitted from the light-emitting layers of the multiple EL layers to obtain white light emission. Note that the structure for obtaining white light emission is the same as the structure in the single-structure device. Furthermore, in the series-connected device, it is preferable to provide an intermediate layer such as a charge-generating layer between the multiple EL layers.

[0215] Furthermore, when comparing the aforementioned white light-emitting devices (single-structure or series-structure) and SBS structure light-emitting devices, the SBS structure light-emitting device exhibits lower power consumption than the white light-emitting device. Therefore, an SBS structure light-emitting device is preferable when power consumption reduction is desired. On the other hand, the manufacturing process for white light-emitting devices is simpler than that for SBS structure light-emitting devices, thereby reducing manufacturing costs or increasing manufacturing yield, making it preferable.

[0216] <Structural Example 3 of Light-Emitting Device 700> The light-emitting device 700 shown in FIG9A includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. Furthermore, light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 disposed on a first substrate 510. The functional layer 520 includes, in addition to driving circuits GD and SD composed of multiple transistors, wiring that electrically connects them. Note that these driving circuits are electrically connected to light-emitting devices 550B, 550G, and 550R, and can drive these devices.

[0217] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 1. In particular, it is shown that each light-emitting device commonly includes an EL layer 103 having the structure shown in FIG. 2B, a so-called series structure.

[0218] The light-emitting device 550B includes an electrode 551B, an electrode 552, EL layers (103P, 103Q), a charge-generating layer 106B, and an insulating layer 107, and has the stacked structure shown in FIG. 9A. Note that the specific structure of each layer is as shown in Embodiment 1. Furthermore, the electrode 551B overlaps with the electrode 552. In addition, the EL layers 103P and 103Q are stacked with the charge-generating layer 106B sandwiched between them, and the EL layers 103P, 103Q, and 106B are included between the electrode 551B and the electrode 552. Note that the EL layers 103P and 103Q, like the EL layers 103, 103a, 103b, and 103c described in Embodiment 1, have a stacked structure composed of multiple layers with different functions, including a light-emitting layer. Furthermore, the EL layer 103P can emit blue light, for example, and the EL layer 103Q can emit yellow light, for example.

[0219] In FIG. 9A, only the hole injection / transport layer 104P is shown in the layers included in EL layer 103P, and only the hole injection / transport layer 104Q, the light-emitting layer 113Q, the electron transport layer 108Q, and the electron injection layer 109 are shown in the layers included in EL layer 103Q. However, one embodiment of the present invention is not limited thereto. For convenience, when describing layers that may also be included in each EL layer, EL layers (EL layer 103P and EL layer 103Q) will sometimes be used. Furthermore, the electron transport layer may also have a stacked structure and may include a hole barrier layer to block holes from moving from the anode side through the light-emitting layer to the cathode side. The electron injection layer 109 may also have a stacked structure, part or all of which may be formed using different materials.

[0220] As shown in FIG9A, the insulating layer 107 is formed on the electrode 551B with photoresist remaining on a portion of the EL layer 103Q (in this embodiment, the electron transport layer 108Q is formed on the light-emitting layer 113Q). Therefore, the insulating layer 107 is formed in contact with the side (or end) of the portion of the EL layer 103Q (described above), the EL layer 103P, and the charge generation layer 106B. This suppresses the entry of oxygen, moisture, or their constituent elements into the interior from the side of the EL layer 103P, the EL layer 103Q, and the charge generation layer 106B. Note that the insulating layer 107 can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. The insulating layer 107 can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method for better coverage.

[0221] An electron injection layer 109 is formed by a layer covering a portion of the EL layer 103Q (an electron transport layer 108Q formed on the light-emitting layer 113Q) and an insulating layer 107. Note that the electron injection layer 109 is preferably a stacked structure of two or more layers having different resistances in the layers. For example, it may also have a structure with a first layer formed using only an electron transport material in contact with the electron transport layer 108Q and a second layer formed using an electron transport material containing a metallic material thereon, or a structure that also includes a third layer formed using an electron transport material containing a metallic material between the first layer and the electron transport layer 108Q.

[0222] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551B and 552 include overlapping regions. Furthermore, EL layers 103P, 103Q, and charge generation layer 106B are included between electrodes 551B and 552. Therefore, electron injection layer 109 is located on the sides (or ends) of EL layers 103Q, EL layers 103P, and charge generation layer 106B, separated by insulating layer 107, or electrode 552 is located on the sides (or ends) of EL layers 103Q, EL layers 103P, and charge generation layer 106B, separated by electron injection layer 109 and insulating layer 107. This prevents short circuits between EL layer 103P and electrode 552, and more specifically, between the hole injection / transport layer 104P included in EL layer 103P and electrode 552. Furthermore, it can prevent short circuits between the EL layer 103Q and the electrode 552, and more specifically, between the hole injection / transport layer 104Q included in the EL layer 103Q and the electrode 552. Additionally, it can prevent short circuits between the charge generation layer 106B and the electrode 552.

[0223] The light-emitting device 550G includes an electrode 551G, an electrode 552, an EL layer (103P, 103Q), a charge-generating layer 106G, and an insulating layer 107, and has the stacked structure shown in FIG. 9A. Note that the specific structure of each layer is as shown in Embodiment 1. Furthermore, the electrode 551G overlaps with the electrode 552. In addition, the EL layer 103P and the EL layer 103Q are stacked with the charge-generating layer 106G sandwiched between them, and the EL layer 103P, the EL layer 103Q, and the charge-generating layer 106G are included between the electrode 551G and the electrode 552.

[0224] As shown in FIG9A, the insulating layer 107 is formed on the electrode 551G with photoresist remaining on a portion of the EL layer 103Q (in this embodiment, the electron transport layer 108Q is formed on the light-emitting layer 113Q). Therefore, the insulating layer 107 is formed in contact with the side (or end) of the portion of the EL layer 103Q (described above), the EL layer 103P, and the charge generation layer 106G. This suppresses the entry of oxygen, moisture, or their constituent elements into the interior from the side of the EL layer 103P, the EL layer 103Q, and the charge generation layer 106G. Note that the insulating layer 107 can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. The insulating layer 107 can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method, which has good coverage.

[0225] An electron injection layer 109 is formed by a layer covering a portion of the EL layer 103Q (an electron transport layer 108Q formed on the light-emitting layer 113Q) and an insulating layer 107. Note that the electron injection layer 109 is preferably a stacked structure with two or more layers having different resistances in the layers. For example, it may also have a structure with a first layer formed using only an electron transport material in contact with the electron transport layer 108Q and a second layer formed using an electron transport material containing a metallic material thereon, or a structure that also includes a third layer formed using an electron transport material containing a metallic material between the first layer and the electron transport layer 108Q.

[0226] Electrode 552 is formed on electron injection layer 109. Note that electrode 551G and electrode 552 include overlapping regions. Furthermore, EL layer 103P, EL layer 103Q, and charge generation layer 106G are included between electrode 551G and electrode 552. Therefore, electron injection layer 109 is located on the side (or end) of EL layer 103Q, EL layer 103P, and charge generation layer 106G with the insulating layer 107 in between, or electrode 552 is located on the side (or end) of EL layer 103Q, EL layer 103P, and charge generation layer 106G with the electron injection layer 109 and the insulating layer 107 in between. This prevents short circuit between EL layer 103P and electrode 552, and more specifically, between the hole injection / transport layer 104P included in EL layer 103P and electrode 552. Furthermore, it can prevent short circuits between the EL layer 103Q and the electrode 552, and more specifically, between the hole injection / transport layer 104Q included in the EL layer 103Q and the electrode 552. Additionally, it can prevent short circuits between the charge generation layer 106G and the electrode 552.

[0227] The light-emitting device 550R includes an electrode 551R, an electrode 552, an EL layer (103P, 103Q), a charge-generating layer 106R, and an insulating layer 107, and has the stacked structure shown in FIG. 9A. Note that the specific structure of each layer is as shown in Embodiment 1. Furthermore, the electrode 551R overlaps with the electrode 552. In addition, the EL layer 103P and the EL layer 103Q are stacked with the charge-generating layer 106R sandwiched between them, and the EL layer 103P, the EL layer 103Q, and the charge-generating layer 106R are included between the electrode 551R and the electrode 552.

[0228] As shown in FIG9A, the insulating layer 107 is formed on the electrode 551R with photoresist remaining on a portion of the EL layer 103Q (in this embodiment, the electron transport layer 108Q is formed on the light-emitting layer 113Q). Therefore, the insulating layer 107 is formed in contact with the side (or end) of the portion of the EL layer 103Q (described above), the EL layer 103P, and the charge generation layer 106R. This suppresses the entry of oxygen, moisture, or their constituent elements into the interior from the side of the EL layer 103P, the EL layer 103Q, and the charge generation layer 106R. Note that the insulating layer 107 can be made of, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride. The insulating layer 107 can be formed using sputtering, CVD, MBE, PLD, ALD, etc., and is preferably formed using the ALD method, which has good coverage.

[0229] An electron injection layer 109 is formed by a layer covering a portion of the EL layer 103Q (an electron transport layer 108Q formed on the light-emitting layer 113Q) and an insulating layer 107. Note that the electron injection layer 109 is preferably a stacked structure with two or more layers having different resistances in the layers. For example, it may also have a structure with a first layer formed using only an electron transport material that contacts the electron transport layer 108Q and a second layer formed using an electron transport material containing a metallic material thereon, or a structure that also includes a third layer formed using an electron transport material containing a metallic material between the first layer and the electron transport layer 108Q.

[0230] Electrode 552 is formed on electron injection layer 109. Note that electrodes 551R and 552 have overlapping areas. Furthermore, EL layers 103P, EL layers 103Q, and charge generation layer 106R are included between electrodes 551R and 552. Thus, electron injection layer 109 is located on the side (or end) of EL layers 103Q, EL layers 103P, and charge generation layer 106R, separated by insulating layer 107, or electrode 552 is located on the side (or end) of EL layers 103Q, EL layers 103P, and charge generation layer 106R, separated by electron injection layer 109 and insulating layer 107. This prevents short circuits between EL layer 103P and electrode 552, and more specifically, between the hole injection / transport layer 104P included in EL layer 103P and electrode 552. Furthermore, it can prevent short circuits between the EL layer 103Q and the electrode 552, and more specifically, between the hole injection / transport layer 104Q included in the EL layer 103Q and the electrode 552. Additionally, it can prevent short circuits between the charge generation layer 106R and the electrode 552.

[0231] Note that when the EL layer (103P, 103Q) and charge generation layer (106B, 106G, 106R) included in each light-emitting device are processed separately for each light-emitting device, the ends (sides) of the processed EL layer (EL layer 103P, hole injection / transport layer 104Q, light-emitting layer 113Q and electron transport layer 108Q) and charge generation layer 106 are shaped to have approximately the same surface (or, located on approximately the same plane) due to the patterning using photolithography.

[0232] The EL layer (103P, 103Q) and charge generation layer (106B, 106G, 106R) included in each light-emitting device are respectively separated by a gap 580 between adjacent light-emitting devices. Since the hole injection layer and charge generation layer (106B, 106G, 106R) included in the hole transport region of the EL layer (103P, 103Q) have high conductivity in many cases, crosstalk sometimes occurs when the hole injection layer and charge generation layer (106B, 106G, 106R) are formed as layers shared by adjacent light-emitting devices. Therefore, as shown in this structural example, crosstalk occurring between adjacent light-emitting devices can be suppressed by providing the gap 580.

[0233] In high-definition light-emitting devices (display panels) with a resolution exceeding 1000 ppi, crosstalk occurs when electrical conduction occurs between EL layers 103B, EL layers 103G, and EL layers 103R, thus narrowing the color gamut that the light-emitting device can display. By setting a gap 580 in high-definition display panels with a resolution exceeding 1000 ppi, preferably high-definition display panels with a resolution exceeding 2000 ppi, and more preferably ultra-high-definition display panels with a resolution exceeding 5000 ppi, a display panel capable of displaying vibrant colors can be provided.

[0234] In this structural example, light-emitting devices 550B, 550G, and 550R all emit white light. Therefore, the second substrate 770 includes a color layer CFB, a color layer CFG, and a color layer CFR. Note that these color layers can also partially overlap, as shown in FIG9A. By partially overlapping the aforementioned color layers, the overlapping portion can also be used as a light-shielding film. In this structural example, for example, the color layer CFB uses a material that preferentially transmits blue light (B), the color layer CFG uses a material that preferentially transmits green light (G), and the color layer CFR uses a material that preferentially transmits red light (R).

[0235] Figure 9B shows the structure of light-emitting device 550B when it emits white light, light-emitting device 550G, and light-emitting device 550R. An EL layer 103P and an EL layer 103Q are stacked on an electrode 551B with a charge generation layer 106B sandwiched between them. In addition, the EL layer 103P includes a light-emitting layer 113B that emits blue light EL (1), and the EL layer 103Q includes a light-emitting layer 113G that emits green light EL (2) and a light-emitting layer 113R that emits red light EL (3).

[0236] Note that a color conversion layer can be used instead of the color layer described above. For example, nanoparticles, quantum dots, etc., can be used for the color conversion layer.

[0237] For example, a color conversion layer that converts blue light to green light can be used instead of the color layer CFG. This allows the blue light emitted by the light-emitting device 550G to be converted into green light. Alternatively, a color conversion layer that converts blue light to red light can be used instead of the color layer CFR. This allows the blue light emitted by the light-emitting device 550R to be converted into red light.

[0238] <Example 4 of the structure of the light-emitting device 700> The light-emitting device (display panel) 700 shown in FIG10 includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. Furthermore, the light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 disposed on a first substrate 510. The functional layer 520 includes, in addition to driving circuits GD and SD composed of multiple transistors, wiring that electrically connects them. Note that these driving circuits are electrically connected to the light-emitting devices 550B, 550G, and 550R, and can drive these devices.

[0239] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 1. In particular, this is suitable for cases where each light-emitting device commonly includes an EL layer 103 having the structure shown in FIG. 2B, the so-called series structure.

[0240] Note that the specific structure of each light-emitting device shown in Figure 10 is the same as that of light-emitting devices 550B, 550G and 550R described in Figure 9A. These devices all emit white light.

[0241] Note that the light-emitting device shown in this structural example differs from the light-emitting device shown in FIG9A in that it includes color layers CFB, CFG and CFR formed on each light-emitting device on the first substrate 510.

[0242] That is, each light-emitting device electrode 552 formed on the first substrate 510 includes an insulating layer 573, and the insulating layer 573 includes a color layer CFB, a color layer CFG and a color layer CFR.

[0243] Furthermore, an insulating layer 705 is included on the color layers CFB, CFG, and CFR. The insulating layer 705 includes a region sandwiched between the first substrate 510 and the second substrate 770 on the side near the color layers (CFB, CFG, and CFR). The first substrate 510 is provided with a functional layer 520, various light-emitting devices (550B, 550G, and 550R), and the color layers CFB, CFG, and CFR. The insulating layer 705 has the function of bonding the first substrate 510 and the second substrate 770.

[0244] Note that the above-mentioned insulating layer 573 and insulating layer 705 may be made of inorganic materials, organic materials or a mixture of inorganic and organic materials.

[0245] Note that inorganic oxide films, inorganic nitride films, or inorganic oxynitride films, or stacked materials containing multiple films selected from these films, can be used as inorganic materials. For example, silicon oxide films, silicon nitride films, silicon oxynitride films, aluminum oxide films, or films containing stacked materials containing multiple films selected from these films can be used. Furthermore, silicon nitride films are dense films and have excellent impurity diffusion suppression capabilities. Alternatively, oxide semiconductors (e.g., IGZO films) can have a stacked structure of an aluminum oxide film and an IGZO film on that aluminum oxide film.

[0246] As an organic material, polyester, polyolefin, polyamide, polyimide, polycarbonate, polysiloxane or acrylic acid, or laminates or composites of multiple resins selected from the above resins can be used. Alternatively, reaction-curing adhesives, light-curing adhesives, thermosetting adhesives and / or anaerobic adhesives can be used.

[0247] <Example 2 of manufacturing method of light-emitting device> Next, the manufacturing method of the light-emitting device shown in FIG10 will be described with reference to FIG11A to FIG11C and FIG12A and FIG12B.

[0248] As shown in FIG11A, an EL layer 103P (including a hole injection / transport layer 104P), a charge generation layer 106 that becomes a charge generation layer (106B, 106G, 106R), a hole injection / transport layer 104Q, a light-emitting layer 113Q, and an electron transport layer 108Q are formed on the electrodes (551B, 551G, 551R) and the partition wall 528 (see FIG4B) formed on the first substrate 510 in such a way as to cover them.

[0249] Next, as shown in FIG11B, the EL layer 103P (including the hole injection / transport layer 104P), charge generation layer 106, hole injection / transport layer 104Q, light-emitting layer 113Q, and electron transport layer 108Q on the electrodes (551B, 551G, 551R) are processed into a predetermined shape. For example, photoresist REG is formed on the hole injection / transport layer 104Q, light-emitting layer 113Q, and electron transport layer 108Q on the electrodes (551G, 551B, 551R) using photolithography, and the portion on which the photoresist REG is not formed is removed by etching, thus processing it into a shape with sides (or exposed sides), in other words, processing it into a strip shape extending in the direction intersecting the plane of the paper (X-axis direction) of the drawing. Specifically, dry etching is performed using the photoresist REG formed on the electron transport layer 108Q (see FIG11C). Note that the separator 528 can be used as an etching stop layer.

[0250] Next, an insulating layer 107 is formed on the photoresist REG, the EL layer 103P, the charge generation layers (106B, 106G, 106R), the hole injection / transport layer 104Q, the light-emitting layer 113Q, the electron transport layer 108Q, and the separator 528. For example, the insulating layer 107 is formed on the photoresist REG, the EL layer 103P, the charge generation layers (106B, 106G, 106R), the hole injection / transport layer 104Q, the light-emitting layer 113Q, the electron transport layer 108Q, and the separator 528 in a manner that covers them, using the ALD method. At this time, the insulating layer 107 is formed in contact with the side surfaces of the EL layer 103P, the charge generation layers (106B, 106G, 106R), the hole injection / transport layer 104Q, the light-emitting layer 113Q, and the electron transport layer 108Q, as shown in FIG11C. This prevents oxygen, moisture, or their constituent elements from entering the interior from the sides of the EL layer 103P, the charge generation layers (106B, 106G, 106R), the hole injection / transport layer 104Q, the light-emitting layer 113Q, and the electron transport layer 108Q. Note that materials used for the insulating layer 107 can include, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxynitride.

[0251] Next, as shown in FIG12A, the photoresist REG is removed to form an electron injection layer 109 on the insulating layer 107, the electron transport layer 108Q, and the separator 528. The electron injection layer 109 is formed, for example, by vacuum evaporation. Note that the electron injection layer 109 is located on the side of a portion of the EL layers 103P and 103Q (hole injection / transport layer 104Q, light-emitting layer 113Q, and electron transport layer 108Q) and the charge generation layers (106B, 106G, 106R) across the insulating layer 107.

[0252] Next, an electrode 552 is formed on the electron injection layer 109. The electrode 552 is formed, for example, by vacuum evaporation. Note that the electrode 552 is located on the side (or end) of a portion of the EL layers 103P and 103Q (hole injection / transport layer 104Q, light-emitting layer 113Q, and electron transport layer 108Q) and the charge generation layers (106B, 106G, 106R) across the electron injection layer 109 and the insulating layer 107. This prevents short circuits between each EL layer (103P, 103Q) and the electrode 552, and more specifically, between the hole injection / transport layers (104P, 104Q) included in each EL layer (103P, 103Q) and the electrode 552.

[0253] As described above, the EL layer 103P (including hole injection / transport layer 104P), charge generation layers (106B, 106G, 106R), and a portion of the EL layer 103Q (including hole injection / transport layer 104Q, light emission layer 113Q, and electron transport layer 108Q) of the light emission devices 550B, 550G, and 550R can be formed by patterning using a single photolithography method.

[0254] As the material used for the electron injection layer 109, the hole transport material described in Embodiment 1 can be used.

[0255] Note that the electron injection layer 109 is also formed on the side exposed during the etching process of the EL layer 103P (including the hole injection / transport layer 104P), the charge generation layers (106B, 106G, 106R) and the EL layer 103Q (including the hole injection / transport layer 104Q and the electron transport layer 108Q).

[0256] Electrode 552 is formed on electron injection layer 109. Note that electrode 552 is located on the side of EL layer 103P (including hole injection / transport layer 104P), charge generation layers (106B, 106G, 106R), and a portion of EL layer 103Q (including hole injection / transport layer 104Q, light-emitting layer 113Q, and electron transport layer 108Q) separated by insulating layer 107. This prevents short circuits between EL layer 103P and electrode 552, and more specifically, between the hole injection / transport layer 104P included in EL layer 103P and electrode 552. Furthermore, it prevents short circuits between EL layer 103Q and electrode 552, and more specifically, between the hole injection / transport layer 104Q included in EL layer 103Q and electrode 552. Additionally, it prevents short circuits between charge generation layers (106B, 106G, 106R) and electrode 552.

[0257] Next, insulating layer 573, color layer CFB, color layer CFG, color layer CFR and insulating layer 705 are formed (see Figure 12B).

[0258] For example, a planar film and a dense film are stacked to form an insulating layer 573. Specifically, a planar film is formed using a coating method, and a dense film is stacked on the planar film using a chemical vapor deposition method or an atomic layer deposition method (ALD). As a result, a high-quality insulating layer 573 with few defects can be formed.

[0259] For example, a color layer CFB, a color layer CFG, and a color layer CFR are formed into a specified shape using a color photoresist. Note that the process is performed such that the color layer CFR overlaps the color layer CFB on the partition wall 528. This suppresses the phenomenon of light emitted by a light-emitting device entering an adjacent light-emitting device.

[0260] The insulating layer 705 may be made of inorganic materials, organic materials, or composite materials of inorganic and organic materials.

[0261] Note that when the EL layer (103P, 103Q) and charge generation layer (106B, 106G, 106R) included in each light-emitting device are processed separately for each light-emitting device, a high-definition light-emitting device (display panel) can be manufactured by patterning using photolithography. In addition, the ends (sides) of the EL layer processed by patterning using photolithography have a shape having approximately the same surface (or located on approximately the same surface).

[0262] In many cases, the hole injection layer and charge generation layer (106B, 106G, 106R) included in the hole transport region of the EL layer (103P, 103Q) have high conductivity. Therefore, when the hole injection layer and charge generation layer (106B, 106G, 106R) are formed as layers shared by adjacent light-emitting devices, crosstalk sometimes occurs. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layers.

[0263] <Structural Example 5 of Light-Emitting Device 700> The light-emitting device (display panel) 700 shown in FIG13 includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. Furthermore, the light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 disposed on a first substrate 510. The functional layer 520 includes, in addition to driving circuits GD and SD composed of multiple transistors, wiring that electrically connects them. Note that these driving circuits are electrically connected to the light-emitting devices 550B, 550G, and 550R, and can drive these devices.

[0264] Note that light-emitting devices 550B, 550G, and 550R have the device structure shown in Embodiment 1. In particular, this is suitable for cases where each light-emitting device commonly includes an EL layer 103 having the structure shown in FIG. 2B, the so-called series structure.

[0265] As shown in FIG13, a gap 580 is included between each light-emitting device, for example, between light-emitting device 550B and light-emitting device 550G. Therefore, an insulating layer 540 is formed in the gap 580.

[0266] For example, by performing patterning using photolithography, after separating and forming the EL layer 103P (including the hole injection / transport layer 104P), the charge generation layers (106B, 106G, 106R), and the EL layer 103Q (including the hole injection / transport layer 104Q), an insulating layer 540 can be formed in the gap 580 on the partition wall 528 using photolithography. Furthermore, an electrode 552 can be formed on the EL layer 103Q (including the hole injection / transport layer 104Q) and the insulating layer 540.

[0267] Note that in this structure, since each EL layer is completely separated by the insulating layer 540, it is not necessary to set the insulating layer 107 shown in structural example 3 (see Figure 9A).

[0268] Note that when the EL layers (103P, 103Q) and charge generation layers (106B, 106G, 106R) included in each light-emitting device are processed separately for each light-emitting device, a high-definition light-emitting device (display panel) can be manufactured by patterning using photolithography. Furthermore, the ends (sides) of the EL layers processed by patterning using photolithography have a shape having approximately the same surface (or located on approximately the same surface).

[0269] In many cases, the hole injection layer and charge generation layer (106B, 106G, 106R) included in the hole transport region of the EL layer (103P, 103Q) have high conductivity. Therefore, when the hole injection layer and charge generation layer (106B, 106G, 106R) are formed as layers shared by adjacent light-emitting devices, crosstalk sometimes occurs. Therefore, as shown in this structural example, crosstalk between adjacent light-emitting devices can be suppressed by performing patterning using photolithography to separate the EL layers.

[0270] The structure shown in this embodiment can be used in combination with the structures shown in other embodiments as appropriate.

[0271] Embodiment 3 In this embodiment, a light-emitting device according to an embodiment of the present invention will be described with reference to FIGS. 14A to 16B. Note that the light-emitting device 700 shown in FIGS. 14A to 16B includes the light-emitting device shown in Embodiment 1. Furthermore, since the light-emitting device 700 described in this embodiment can be used in the display section of electronic devices, etc., it can also be referred to as a display panel.

[0272] The light-emitting device 700 described in this embodiment includes a display area 231 as shown in FIG14A, and the display area 231 includes a group of pixels 703(i,j). In addition, as shown in FIG14B, there is a group of pixels 703(i+1,j) that include adjacent groups of pixels 703(i,j).

[0273] Note that pixel 703(i,j) can use multiple pixels. For example, multiple pixels that display different hues can be used. Note that each of the multiple pixels can be referred to as a subpixel. Alternatively, multiple subpixels can be grouped together and referred to as pixels.

[0274] Thus, additive or subtractive color mixing can be performed on the colors displayed by the multiple pixels. In addition, colors with hues that cannot be displayed by individual pixels can be displayed.

[0275] Specifically, the pixel 702B(i,j) that displays blue, the pixel 702G(i,j) that displays green, and the pixel 702R(i,j) that displays red can be used for pixel 703(i,j). Furthermore, each of the pixels 702B(i,j), 702G(i,j), and 702R(i,j) can be referred to as a sub-pixel.

[0276] Alternatively, pixels that display white or the like can be added to the above set and used for pixel 703(i,j). Alternatively, each of the pixels that display cyan, magenta, and yellow can be used as a sub-pixel for pixel 703(i,j).

[0277] In addition to the above-mentioned set, pixels that emit infrared light can also be used for pixels 703(i,j). Specifically, pixels that emit light containing wavelengths of 650 nm or more and 1000 nm or less can be used for pixels 703(i,j).

[0278] The display area 231 shown in FIG14A is surrounded by drive circuits GD and SD. It also includes terminals 519 electrically connected to drive circuits GD and SD. Terminals 519 may, for example, be electrically connected to flexible printed circuit FPC1 (see FIG16A and FIG16B).

[0279] Note that the driving circuit GD has the function of supplying a first selection signal and a second selection signal. For example, the driving circuit GD is electrically connected to the conductive films G1(i) and G2(i) described later and supplies the first selection signal and the second selection signal respectively. The driving circuit SD has the function of supplying an image signal and a control signal, and the control signal has a first level and a second level. For example, the driving circuit SD is electrically connected to the conductive films S1g(j) and S2g(j) described later and supplies the image signal and the control signal respectively.

[0280] As shown in FIG16A, the light-emitting device 700 includes a functional layer 520 between the first substrate 510 and the second substrate 770. In addition to the aforementioned driving circuits GD and SD, the functional layer 520 also includes wiring that electrically connects them. FIG16A shows the structure of the functional layer 520 including pixel circuits 530B(i,j), pixel circuits 530G(i,j) and driving circuits GD, but is not limited to this structure.

[0281] Each pixel circuit included in the functional layer 520 (e.g., pixel circuit 530B(i,j) and pixel circuit 530G(i,j) shown in FIG. 16A) is electrically connected to each light-emitting device formed on the functional layer 520 (e.g., light-emitting device 550B(i,j) and light-emitting device 550G(i,j) shown in FIG. 16A). Furthermore, an insulating layer 705 is provided on the functional layer 520 and each light-emitting device, and the insulating layer 705 has the function of adhering the second substrate 770 to the functional layer 520.

[0282] Note that the second substrate 770 can be a substrate having touch sensors in a matrix configuration. For example, a substrate including an electrostatic capacitive touch sensor or an optical touch sensor can be used as the second substrate 770. Thus, the light-emitting device of one embodiment of the present invention can be used as a touch panel.

[0283] Figure 15A shows the specific structure of pixel circuit 530G(i,j).

[0284] As shown in Figure 15A, the pixel circuit 530G(i,j) includes switch SW21, switch SW22, transistor M21, capacitor C21, and node N21. Additionally, the pixel circuit 530G(i,j) includes node N22, capacitor C22, and switch SW23.

[0285] The transistor M21 includes a gate electrode electrically connected to node N21, a first electrode electrically connected to the light-emitting device 550G(i,j), and a second electrode electrically connected to the conductive film ANO.

[0286] The switch SW21 includes a first terminal electrically connected to node N21, a second terminal electrically connected to conductive film S1g(j), and has the function of controlling the on state or the off state according to the potential of conductive film G1(i).

[0287] The switch SW22 includes a first terminal electrically connected to the conductive film S2g(j) and has the function of controlling the on state or the off state according to the potential of the conductive film G2(i).

[0288] Capacitor C21 includes a conductive film electrically connected to node N21 and a conductive film electrically connected to the second electrode of switch SW22.

[0289] Thus, the image signal can be stored in node N21. Furthermore, the potential of node N21 can be changed using switch SW22. Additionally, the intensity of the light emitted by the light-emitting device 550G(i,j) can be controlled using the potential of node N21.

[0290] Next, FIG15B shows an example of a specific structure of the transistor M21 illustrated in FIG15A. Note that, as transistor M21, a bottom-gate transistor or a top-gate transistor, etc., can be appropriately used.

[0291] The transistor shown in FIG15B includes a semiconductor film 508, a conductive film 504, an insulating film 506, a conductive film 512A, and a conductive film 512B. The transistor is formed, for example, on the insulating film 501C.

[0292] The semiconductor film 508 includes a region 508A electrically connected to the conductive film 512A and a region 508B electrically connected to the conductive film 512B. The semiconductor film 508 includes a region 508C between the regions 508A and 508B.

[0293] The conductive film 504 includes a region that overlaps with the region 508C, and the conductive film 504 has the function of a gate electrode.

[0294] The insulating film 506 includes a region sandwiched between the semiconductor film 508 and the conductive film 504. The insulating film 506 functions as a gate insulating film.

[0295] The conductive film 512A has one of the functions of a source electrode and a drain electrode, and the conductive film 512B has the other of the functions of a source electrode and a drain electrode.

[0296] Alternatively, the conductive film 524 can be used for a transistor. The conductive film 524 includes a region in which a semiconductor film 508 is sandwiched between it and the conductive film 504. The conductive film 524 functions as a second gate electrode. An insulating film 501D is sandwiched between the semiconductor film 508 and the conductive film 524 and functions as a second gate insulating film.

[0297] In the process of forming a semiconductor film for a transistor used in a pixel circuit, a semiconductor film for a transistor used in a driving circuit can also be formed. For example, a semiconductor film having the same composition as the semiconductor film in the transistor of the pixel circuit can be used in a driving circuit.

[0298] In addition, semiconductors containing Group 14 elements can be used in semiconductor film 508. Specifically, semiconductors containing silicon can be used in semiconductor film 508.

[0299] Furthermore, hydrogenated amorphous silicon can be used in the semiconductor film 508. Alternatively, microcrystalline silicon or the like can be used in the semiconductor film 508. Thus, for example, a light-emitting device with less display non-uniformity can be provided compared to a light-emitting device (or display panel) using polycrystalline silicon in the semiconductor film 508. Alternatively, it is easier to scale up the light-emitting device.

[0300] Furthermore, polycrystalline silicon can be used in the semiconductor film 508. This allows, for example, a higher field-effect mobility than that achieved with a transistor using hydrogenated amorphous silicon in the semiconductor film 508. Furthermore, for example, a higher driving capability than that achieved with a transistor using hydrogenated amorphous silicon in the semiconductor film 508 can be achieved. Alternatively, for example, a higher pixel aperture ratio than that achieved with a transistor using hydrogenated amorphous silicon in the semiconductor film 508 can be achieved.

[0301] Alternatively, for example, higher reliability can be achieved than that of transistors using hydrogenated amorphous silicon in semiconductor film 508.

[0302] Alternatively, for example, the temperature required to manufacture the transistor can be lower than that required for a transistor using single-crystal silicon.

[0303] Alternatively, the semiconductor film for the transistor used in the driving circuit and the semiconductor film for the transistor used in the pixel circuit can be formed using the same process. Alternatively, the driving circuit can be formed on the same substrate as the substrate on which the pixel circuit is formed. Alternatively, the number of components constituting the electronic device can be reduced.

[0304] Furthermore, monocrystalline silicon can be used in the semiconductor film 508. This allows, for example, a higher resolution than that achieved with hydrogenated amorphous silicon in the semiconductor film 508. Alternatively, for example, a light-emitting device with less display inhomogeneity can be provided compared to a light-emitting device with polycrystalline silicon in the semiconductor film 508. Alternatively, for example, smart glasses or head-mounted displays can be provided.

[0305] Furthermore, metal oxides can be used in the semiconductor film 508. Therefore, compared to pixel circuits using transistors with hydrogenated amorphous silicon in the semiconductor film, the time the pixel circuit can maintain the image signal can be extended. Specifically, flicker can be suppressed, and a selection signal can be supplied at a frequency of less than 30 Hz, preferably less than 1 Hz, and more preferably less than 1 time / min. As a result, eye fatigue for users of electronic devices can be reduced. Additionally, power consumption for driving can be reduced.

[0306] In addition, oxide semiconductors can be used in semiconductor film 508. Specifically, oxide semiconductors containing indium, oxide semiconductors containing indium, gallium and zinc, or oxide semiconductors containing indium, gallium, zinc and tin can be used in semiconductor film 508.

[0307] By using oxide semiconductors in the semiconductor film, a transistor with a smaller leakage current in the off state can be obtained compared to a transistor using hydrogenated amorphous silicon in the semiconductor film. Therefore, it is preferable to use a transistor using oxide semiconductors in the semiconductor film as a switch, etc. Note that a circuit using an oxide semiconductor transistor in the semiconductor film as a switch can maintain the potential of the floating node for a longer period of time compared to a circuit using a hydrogenated amorphous silicon transistor in the semiconductor film as a switch.

[0308] Although Figure 16A shows a light-emitting device with a structure that extracts light from the second substrate 770 side (top-emitting type), a light-emitting device with a structure that extracts light from the first substrate 510 side (bottom-emitting type), as shown in Figure 16B, can also be used. Note that in the bottom-emitting type light-emitting device, the first electrode 101 is used as a semi-transmissive and semi-reflective electrode, and the second electrode 102 is used as a reflective electrode.

[0309] Although Figures 16A and 16B illustrate an active matrix type light-emitting device, the structure of the light-emitting device shown in Embodiment 1 can also be used in the passive matrix type light-emitting device shown in Figures 17A and 17B.

[0310] Figure 17A is a perspective view showing a passive matrix type light-emitting device, and Figure 17B is a cross-sectional view along line XY in Figure 17A. In Figures 17A and 17B, an EL layer 955 is disposed between electrodes 952 and 956 on the substrate 951. The end of electrode 952 is covered by an insulating layer 953. An isolation layer 954 is disposed on the insulating layer 953. The sidewalls of the isolation layer 954 have an inclination such that the spacing between one sidewall and the other sidewall becomes narrower closer to the substrate surface. That is, the cross-section of the isolation layer 954 in the short axis direction is trapezoidal, and the lower base (the side in contact with the insulating layer 953) is shorter than the upper base. In this way, by providing the isolation layer 954, malfunctions of the light-emitting device caused by static electricity, etc., can be prevented.

[0311] The structure shown in this embodiment can be used in combination with the structures shown in other embodiments.

[0312] Embodiment 4 In this embodiment, the structure of an electronic device according to an embodiment of the present invention will be described with reference to FIGS. 18A to 20B.

[0313] Figures 18A to 20B are diagrams illustrating the structure of an electronic device according to one embodiment of the present invention. Figure 18A is a block diagram of the electronic device, and Figures 18B to 18E are perspective views illustrating the structure of the electronic device. Figures 19A to 19E are perspective views illustrating the structure of the electronic device. Figures 20A and 20B are perspective views illustrating the structure of the electronic device.

[0314] The electronic device 5200B described in this embodiment includes an arithmetic unit 5210 and an input / output unit 5220 (see Figure 18A).

[0315] The computing device 5210 has the function of being supplied with operation data and the function of supplying image data according to the operation data.

[0316] The input / output device 5220 includes a display unit 5230, an input unit 5240, a detection unit 5250, and a communication unit 5290, and has the functions of supplying operation data and receiving image data. In addition, the input / output device 5220 has the functions of supplying detection data, supplying communication data, and receiving communication data.

[0317] The input unit 5240 has the function of supplying operation data. For example, the input unit 5240 supplies operation data according to the operation of the user of the electronic device 5200B.

[0318] Specifically, keyboards, hardware buttons, pointing devices, touch sensors, illuminance sensors, camera devices, audio input devices, gaze input devices, posture detection devices, etc., can be used in the input unit 5240.

[0319] The display unit 5230 includes a display panel and has the function of displaying image data. For example, the display panel described in Embodiment 2 can be used in the display unit 5230.

[0320] The testing unit 5250 has the function of supplying testing data. For example, it has the function of supplying testing data using the environment surrounding the testing electronic device.

[0321] Specifically, illuminance sensors, camera devices, posture detection devices, pressure sensors, human body sensors, etc., can be used in the detection unit 5250.

[0322] The communications unit 5290 has the function of supplying communications data and the function of supplying communications data. For example, it has the function of connecting with other electronic devices or communications networks via wireless or wired communications. Specifically, it has the functions of wireless local area network communications, telephone communications, and short-range wireless communications.

[0323] Figure 18B shows an electronic device having an outline along a cylindrical column or the like. As an example, a digital signage unit or the like can be cited. The display panel of one embodiment of the present invention can be used in the display unit 5230. Note that it may also have a function to change the display method according to the illumination of the usage environment. Furthermore, it has a function to sense the presence of a human body and change the displayed content. Therefore, it can be installed, for example, on a column of a building. Alternatively, it can display advertisements or guides.

[0324] Figure 18C shows an electronic device with the function of generating image data based on the trajectory of an indicator used by the user. Examples include electronic blackboards, electronic message boards, and digital signage. Specifically, a display panel with a diagonal length of 20 inches or more, preferably 40 inches or more, and more preferably 55 inches or more can be used. Alternatively, multiple display panels can be arranged to form a single display area. Alternatively, multiple display panels can be arranged to form a multi-screen display panel.

[0325] Figure 18D shows an electronic device that can receive data from other devices and display it on the display unit 5230. Wearable electronic devices can be cited as an example. Specifically, several options can be displayed, or the user can select several options and reply to the sender of the data. Furthermore, for example, it has a function to change the display method according to the illumination of the usage environment. This, for example, can reduce the power consumption of the wearable electronic device. Additionally, for example, images can be displayed on the wearable electronic device in a way that allows for suitable use even in environments with strong external light, such as outdoors on a sunny day.

[0326] FIG18E shows an electronic device including a display section 5230 having a gently curved side surface along the casing. As an example, a mobile phone can be cited. Furthermore, the display section 5230 includes a display panel, which, for example, has the function of displaying on its front, sides, top, and back. Thus, for example, data can be displayed not only on the front of the mobile phone, but also on the sides, top, and back of the mobile phone.

[0327] Figure 19A shows an electronic device that can receive data from the Internet and display it on the display unit 5230. A smartphone can be cited as an example. For instance, notifications can be viewed on the display unit 5230. Furthermore, the notifications can be sent to other devices. In addition, for example, it has a function to change the display method according to the ambient light level. This reduces the power consumption of the smartphone. Furthermore, for example, images can be displayed on the display unit 5230 in a way that allows for suitable use of the smartphone even in environments with strong external light, such as outdoors on a sunny day.

[0328] Figure 19B shows an electronic device that can use a remote control as an input unit 5240. As an example, a television system can be cited. For instance, data can be received from a radio station or the Internet and displayed on the display unit 5230. Additionally, a detection unit 5250 can capture images of the user. Furthermore, the user's image can be transmitted. Additionally, the user's viewing history can be obtained and provided to a cloud service. Furthermore, recommendation information can be obtained from the cloud service and displayed on the display unit 5230. Furthermore, programs or moving images can be displayed based on the recommendation information. Additionally, for example, it has a function to change the display method according to the ambient light level. Thus, the television system can be used appropriately even in environments with strong external light entering the room on sunny days, allowing images to be displayed on the display unit 5230.

[0329] Figure 19C shows an electronic device that can receive teaching materials from the Internet and display them on the display unit 5230. A tablet computer can be used as an example. Furthermore, a report can be input using the input unit 5240 and sent to the Internet. Additionally, the grading results or evaluations of the report can be obtained from a cloud service and displayed on the display unit 5230. Furthermore, appropriate teaching materials can be selected based on the evaluations and displayed on the display unit 5230.

[0330] For example, image signals can be received from other electronic devices and displayed on the display unit 5230. Alternatively, the display unit 5230 can be mounted on a stand or similar fixture and used as a secondary display. For example, images can be displayed on the display unit 5230 in a way that allows for suitable use of electronic devices even in bright outdoor environments such as on a sunny day.

[0331] Figure 19D shows an electronic device including multiple display units 5230. As an example, a digital camera can be cited. For example, an image captured using the detection unit 5250 can be displayed on the display unit 5230. Furthermore, the captured image can be displayed on the display unit 5230. Additionally, the captured image can be edited using the input unit 5240. Furthermore, text can be added to the captured image. Furthermore, it can be sent to the Internet. Additionally, it has a function to change the shooting conditions according to the ambient light level. Thus, for example, the subject can be displayed on the display unit 5230 in a way that allows for suitable viewing even in bright outdoor environments such as on a sunny day.

[0332] Figure 19E shows an electronic device that can control other electronic devices by using other electronic devices as slaves and using the electronic device of this embodiment as a master. As an example, a portable personal computer can be cited. For example, a portion of the image data can be displayed on the display unit 5230 and another portion of the image data can be displayed on the display unit of another electronic device. Furthermore, an image signal can be supplied. In addition, data written from the input unit of another electronic device can be obtained using the communication unit 5290. Thus, for example, a portable personal computer can be used to utilize a larger display area.

[0333] Figure 20A shows an electronic device including a detection unit 5250 that detects acceleration or orientation. An example could be a goggle-type electronic device. The detection unit 5250 can provide data on the user's position or the direction the user is facing. Furthermore, the electronic device can generate image data for the right eye and image data for the left eye based on the user's position or the direction the user is facing. Additionally, the display unit 5230 includes a display area for the right eye and a display area for the left eye. Thus, for example, a realistic virtual reality space image can be displayed on the display unit 5230.

[0334] Figure 20B shows an electronic device including a camera and a detection unit 5250 for detecting acceleration or orientation. An example is an eyeglass-type electronic device. The detection unit 5250 can provide data on the user's position or the direction the user is facing. Furthermore, the electronic device can generate image data based on the user's position or the direction the user is facing. Thus, for example, data can be added to and displayed on a real-world landscape. Additionally, images of augmented reality can be displayed on the eyeglass-type electronic device.

[0335] Note that this embodiment can be appropriately combined with other embodiments shown in this specification.

[0336] Embodiment 5 In this embodiment, the structure of using the light-emitting device shown in Embodiment 2 in a lighting device will be described with reference to FIGS. 21A and 21B. Note that FIG. 21A is a cross-sectional view along line ef of the top view of the lighting device shown in FIG. 21B.

[0337] In the lighting device of this embodiment, a first electrode 401 is formed on a light-transmitting substrate 400 that serves as a support. The first electrode 401 corresponds to the first electrode 101 in Embodiment 1. When light is extracted from the first electrode 401 side, the first electrode 401 is formed using a light-transmitting material.

[0338] Additionally, a pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0339] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the structure of the EL layer 103 in Embodiment 1 or the structure of the combination of EL layers 103a, 103b, 103c and charge generation layers 106 (106a, 106b). Note that their structures are described in the respective descriptions.

[0340] A second electrode 404 is formed by covering the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in Embodiment 1. When light is extracted from the first electrode 401 side, the second electrode 404 is formed using a material with high reflectivity. Voltage is supplied to the second electrode 404 by connecting the second electrode 404 to the pad 412.

[0341] As described above, the lighting device shown in this embodiment includes a light-emitting device comprising a first electrode 401, an EL layer 403, and a second electrode 404. Since this light-emitting device is a high-efficiency light-emitting device, the lighting device of this embodiment can be a low-power lighting device.

[0342] A lighting device is manufactured by fixing a substrate 400, on which a light-emitting device with the above-described structure is formed, and a sealing substrate 407 using sealing materials 405 and 406. Alternatively, only one of the sealing materials 405 and 406 may be used. Furthermore, the inner sealing material 406 (not shown in FIG. 21B) may be mixed with a desiccant, thereby absorbing moisture and improving reliability.

[0343] Furthermore, by providing the pad 412 and a portion of the first electrode 401 in a manner that extends to the outside of the sealing materials 405 and 406, they can be used as external input terminals. Alternatively, an IC chip 420, on which a converter or the like is mounted, can also be provided on the external input terminal.

[0344] Embodiment 6 In this embodiment, an application example of a lighting device manufactured using a light-emitting device or a part thereof according to an embodiment of the present invention will be described with reference to FIG22.

[0345] As an indoor lighting fixture, the ceiling spotlight 8001 can be used. The ceiling spotlight 8001 is available in direct mounting type and recessed type. This lighting fixture is manufactured by combining a light-emitting device with a housing or cover. In addition, it can also be used in pendant lights (lighting fixtures suspended from the ceiling by wires).

[0346] Furthermore, the floor lamp 8002 illuminates the ground, improving safety underfoot. For example, it is effective in bedrooms, staircases, and corridors. In this case, the size and shape of the floor lamp can be appropriately changed according to the size and structure of the room. Additionally, the floor lamp 8002 can also be a mounted lighting device formed by combining a light-emitting device and a bracket.

[0347] Furthermore, the sheet lighting 8003 is a thin-film lighting device. Because it is used by attaching it to the wall, it does not take up space and can be used for various purposes. In addition, it is easy to achieve large-area coverage. In addition, it can also be attached to curved walls and casings.

[0348] Alternatively, a lighting device 8004 can be used where the light from the light source is controlled to travel only in the desired direction.

[0349] The table lamp 8005 includes a light source 8006, which can be a light-emitting device or a part thereof of an embodiment of the present invention as the light source 8006.

[0350] By using a light-emitting device of one embodiment of the present invention or a light-emitting element thereof in a part of indoor furniture other than those described above, a lighting device with furniture functions can be provided.

[0351] As described above, a wide variety of lighting devices suitable for light-emitting devices can be obtained. Furthermore, such lighting devices are included in one embodiment of the present invention.

[0352] The structure shown in this embodiment can be appropriately combined with the structures shown in other embodiments. Example 1

[0353] In this embodiment, the device structure, manufacturing method, and characteristics of light-emitting device 1 and light-emitting device 2, which are blue fluorescent light-emitting devices manufactured as an embodiment of the present invention, are described. Note that regarding device characteristics, a comparison of device characteristics is performed by manufacturing a comparative light-emitting device 3 and a reference light-emitting device 4. Figure 23 shows the device structure of the light-emitting device used in this embodiment, and Table 1 shows the specific structure. In addition, the chemical formulas of the materials used in this embodiment are shown below.

[0354]

[0355] [Chemical Formula 3]

[0356] <<Manufacturing of Light-Emitting Device>> As shown in FIG23, the light-emitting devices shown in this embodiment all have the following structure: a hole injection layer 911, a hole transport layer 912, a light-emitting layer 913, an electron transport layer 914, and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a substrate 900, and a second electrode 903 is stacked on the electron injection layer 915. In addition, each light-emitting device has a device structure using the same material in each functional layer as shown in Table 1. However, the fabrication processes of these light-emitting devices are somewhat different. In the reference light-emitting device 4, the first electrode 901 to the second electrode 903 and the capping layer (CAP) 904 are formed continuously. On the other hand, in light-emitting device 1, after forming the electron transport layer 914-2, it is temporarily exposed to a nitrogen atmosphere (dew point of -78.0°C, moisture concentration of 0.8 ppm, oxygen concentration of 1 ppm) for 1 hour (also known as N2 exposure treatment), and then the electron injection layer 915, the second electrode 903, and the capping layer 904 are formed sequentially. Furthermore, in light-emitting device 2, after forming the electron transport layer 914-1, it is temporarily exposed to a nitrogen atmosphere (dew point of -78.0°C, moisture concentration of 0.8 ppm, oxygen concentration of 1 ppm) for 1 hour, and then the electron transport layer 914-2, the electron injection layer 915, the second electrode 903, and the capping layer 904 are formed sequentially. Furthermore, in the comparative light-emitting device 3, after the light-emitting layer 913 is formed, it is temporarily exposed to a nitrogen atmosphere (dew point of -78.0°C and moisture concentration of 0.8 ppm and oxygen concentration of 1 ppm) for 1 hour, and then the electron transport layer 914 (914-1, 914-2), the electron injection layer 915, the second electrode 903 and the capping layer 904 are formed sequentially.

[0357] First, a first electrode 901 is formed on a substrate 900. The electrode area is 4 mm² (2 mm × 2 mm). A glass substrate is used as the substrate 900. Furthermore, the first electrode 901 is formed by depositing a 10 nm thick indium tin oxide (ITSO) containing silicon oxide using a sputtering method, followed by depositing a 100 nm thick silver (Ag) layer using a sputtering method, and then depositing a 10 nm thick ITSO layer.

[0358] Here, as a pretreatment, the surface of the substrate 900 is washed with water, calcined at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. Then, the substrate is placed in a vacuum evaporation apparatus whose internal pressure is reduced to about 1×10-4 Pa, and vacuum calcined at 170°C for 30 minutes in the heating chamber of the vacuum evaporation apparatus, and then the substrate is cooled for about 30 minutes.

[0359] Next, a hole injection layer 911 is formed on the first electrode 901. After reducing the pressure inside the vacuum evaporation apparatus to 1×10-4 Pa, a co-evaporation is performed with N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-furo-2-amine (abbreviated as: PCBBiF) and an electron acceptor material (OCHD-003) containing fluorine with a molecular weight of 672 at a weight ratio of PCBBiF:OCHD-003=1:0.03 and a thickness of 10 nm, thereby forming the hole injection layer 911.

[0360] Next, a hole transport layer 912 (hole transport layer 912-1 and hole transport layer 912-2) is formed on the hole injection layer 911. First, hole transport layer 912-1 is formed by vapor deposition using PCBBiF with a thickness of 97.5 nm. Next, hole transport layer 912-2 is formed by vapor deposition using N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviated as: DBfBB1TP) with a thickness of 10 nm.

[0361] Next, a light-emitting layer 913 is formed on the hole transport layer 912.

[0362] Aside from 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviated as αN-βNPAnth), 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02) was used as the guest material (fluorescent material) and co-deposited at a weight ratio of αN-βNPAnth:3,10PCA2Nbf(IV)-02=1:0.015 to form the luminescent layer 913. The thickness was set to 25 nm. Note that, for comparison light-emitting device 3, the surface of the luminescent layer 913 was temporarily exposed to a nitrogen atmosphere (dew point -78.0°C, moisture concentration: 0.8 ppm, oxygen concentration: 1 ppm) for 1 hour for N2 exposure treatment.

[0363] Next, an electron transport layer 914 (electron transport layer 914-1 and electron transport layer 914-2) is formed on the light-emitting layer 913.

[0364] 2-[3'-(9,9-dimethyl-9H-furo-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTzn) with a thickness of 20 nm was vapor-deposited to form an electron transport layer 914-1.

[0365] In the light-emitting device 2, the surface of the electron transport layer 914-1 is temporarily exposed to a nitrogen atmosphere (dew point -78.0°C, moisture concentration: 0.8 ppm, oxygen concentration: 1 ppm) for 1 hour for N2 exposure treatment. Next, the electron transport layer 914-2 is formed by co-evaporation using 2-{4-[9,10-bis(naphthyl-2-yl)-2-anthrayl]phenyl}-1-phenyl-1H-benzimidazole (ZADN) and 8-hydroxyquinoline-lithium (Liq) at a weight ratio of ZADN:Liq = 1:1 and a thickness of 15 nm. Note that in the light-emitting device 1, the surface of the electron transport layer 914-2 is temporarily exposed to a nitrogen atmosphere (moisture concentration: 1 ppm, oxygen concentration: 1 ppm) for 1 hour for N2 exposure treatment.

[0366] Next, an electron injection layer 915 is formed on the electron transport layer 914. The electron injection layer 915 is formed by evaporating lithium fluoride (LiF) with a thickness of 1 nm.

[0367] Next, a second electrode 903 is formed on the electron injection layer 915. The second electrode 903 is formed by co-evaporation of silver (Ag) and magnesium (Mg) in a weight ratio of Ag:Mg = 1:0.1. Note that the thickness is set to 15 nm. Note that in this embodiment, the second electrode 903 is transparent and is used as a cathode.

[0368] Through the above process, a top-emitting light-emitting device is formed on the substrate 900 with an EL layer 902 sandwiched between a pair of electrodes and extracting light from the second electrode 903. Note that the reference light-emitting device 4 shown in Table 1 is a light-emitting device that has not been exposed to a nitrogen atmosphere (N2 exposure) even once in this process. Note that the hole injection layer 911, hole transport layer 912, light-emitting layer 913, electron transport layer 914, and electron injection layer 915 described in the above process are functional layers of the EL layer constituting one embodiment of the present invention. Furthermore, all vapor deposition processes of the manufacturing method shown in this embodiment use a vapor deposition method utilizing resistance heating.

[0369] Furthermore, the light-emitting device manufactured as described above includes a capping layer (CAP) 904 on the second electrode 903. Note that the capping layer 904 is formed by vapor deposition of 4,4',4”-(benzene-1,3,5-triyl)tris(dibenzothiophene) (abbreviated as: DBT3P-II) with a thickness of 80 nm.

[0370] Note that the device formed to the capping layer is sealed by another substrate (not shown). When sealing with another substrate (not shown), the other substrate (not shown) coated with a sealant that cures under ultraviolet light is fixed to substrate 900 in a glove box under a nitrogen atmosphere, and the substrates are bonded to each other in such a way that the sealant is adhered around the light-emitting device formed on substrate 900. During sealing, the sealant is stabilized by irradiating with 365 nm ultraviolet light at 6 J / cm2 and by heat treatment at 80°C for 1 hour.

[0371] <<Operating Characteristics of Light-Emitting Devices>> The operating characteristics of each manufactured light-emitting device were measured. These measurements were performed at room temperature. Furthermore, as a result of the operating characteristics of each light-emitting device, Figure 24 shows the luminance-current density characteristic, Figure 25 shows the luminance-voltage characteristic, Figure 26 shows the current efficiency-luminance characteristic, Figure 27 shows the current density-voltage characteristic, and Figure 28 shows the blue index (BI)-luminance characteristic. Note that luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (manufactured by Topcon, SR-UL1R).

[0372] Note that the blue index (BI) shown in Figure 28 is the value obtained by dividing the current efficiency (cd / A) by the y chromaticity, and is one of the indicators representing the luminous emission characteristics of blue light. Blue light emission tends to have higher color purity with lower y chromaticity. High-purity blue light emission can present a wider range of blue even with a small luminance component. When using high-purity blue light emission, the brightness required to present blue is reduced, thus achieving the effect of reducing power consumption. Therefore, as a method of representing the efficiency of blue light emission, it is appropriate to use BI, which takes into account y chromaticity as one of the indicators of blue purity. It can be said that the higher the BI of the light-emitting device, the better the efficiency of the blue light-emitting device used in the display.

[0373] As can be seen from the above results, the current efficiency and power efficiency of the light-emitting device 1 and the light-emitting device 2 shown in Figures 24 to 28 are slightly different on the low brightness side, but on the high brightness side that affects the characteristics of the light-emitting device, they have the same good luminous efficiency as the reference light-emitting device 4.

[0374] Figure 29 shows the emission spectra of each light-emitting device when a current density (10 mA / cm2 to 15 mA / cm2) is applied to emit light at a brightness of approximately 1000 cd / m2. As can be seen from Figure 29, the emission spectra of these light-emitting devices have a peak near 460 nm, which all originate from the emission of 3,10PCA2Nbf(IV)-O2 contained in the light-emitting layer 913.

[0375] Next, reliability tests were performed on light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4. Figure 30 shows the results of the reliability tests. In Figure 30, the vertical axis represents the normalized brightness (%) when the initial brightness is 100%, and the horizontal axis represents the driving time (h) of the device. Note that a constant current density driving test was performed as a reliability test, that is, the brightness change was measured at a constant current density of 50 mA / cm2 at room temperature. As can be seen from the results shown in Figure 30, light-emitting device 1, which was exposed to N2 after the formation of electron transport layer 914-2, and light-emitting device 2, which was exposed to N2 after the formation of electron transport layer 914-1, exhibited the same level of high reliability as reference light-emitting device 4, which was not exposed to nitrogen atmosphere (N2 exposure) even once during the manufacturing process of the light-emitting device. On the other hand, comparison light-emitting device 3, which was exposed to N2 after the formation of light-emitting layer 913, exhibited low reliability compared to light-emitting device 1 and light-emitting device 2. Therefore, in the formation of the EL layer of a blue fluorescent light-emitting device, as long as the formation of functional layers such as the electron transport layer 914 on the light-emitting layer 913 is not immediately after its formation, even N2 exposure will not easily affect the reliability of the light-emitting device. From this result, it can be seen that atmospheric exposure and pattern formation using photolithography can be performed as long as the functional layers such as the electron transport layer 914 formed on the light-emitting layer 913 are completed. In other words, in the manufacture of multiple light-emitting devices, pattern formation using photolithography can be performed after the formation of functional layers such as the electron transport layer 914, and the subsequently formed functional layers can be used in the formation of a common layer in multiple light-emitting devices, thereby simplifying the process. Example 2

[0376] In this embodiment, the device structure, manufacturing method, and characteristics of a blue fluorescent light-emitting device 5, which is a light-emitting device manufactured as an embodiment of the present invention, are described. In the light-emitting device 5, the surface of the electron transport layer 914-2 is temporarily exposed to a nitrogen atmosphere (moisture concentration: 0.5 ppm, oxygen concentration: 4 ppm) for 1 hour for N2 exposure treatment, and then the electron injection layer 915, the second electrode 903, and the capping layer 904 are formed sequentially. Note that, in order to compare device characteristics, a reference light-emitting device 6 is manufactured without any exposure to a nitrogen atmosphere (N2 exposure). FIG23 shows the device structure of the light-emitting device used in this embodiment, and Table 2 shows the specific structure. In addition, the chemical formulas of the materials used in this embodiment are shown below. Furthermore, the device is manufactured in the same manner as in Example 1.

[0377]

[0378] [Chemical Formula 4]

[0379] The above chemical formulas show 2-[3'-(dibenzothiophene-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoline (abbreviation: 2mDBTBPDBq-II) and 2,9-bis(naphthyl-2-yl)-4,7-diphenyl-1,10-phenoline (abbreviation: NBPhen).

[0380] <<Operating Characteristics of Light-Emitting Devices>> The operating characteristics of each manufactured light-emitting device were measured. These measurements were performed at room temperature. Furthermore, as a result of the operating characteristics of each light-emitting device, Figure 31 shows the luminance-current density characteristic, Figure 32 shows the luminance-voltage characteristic, Figure 33 shows the current efficiency-luminance characteristic, Figure 34 shows the current density-voltage characteristic, and Figure 35 shows the blue index (BI)-luminance characteristic. Note that luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (manufactured by Topcon, SR-UL1R).

[0381] As can be seen from the above results, the current efficiency and power efficiency of the light-emitting device 5 shown in this embodiment are slightly different on the low brightness side in the initial characteristics shown in Figures 31 to 35, but on the high brightness side that affects the characteristics of the light-emitting device, it has the same good luminous efficiency as the reference light-emitting device 6.

[0382] Figure 36 shows the emission spectra of each light-emitting device when a current density (10 mA / cm2 to 20 mA / cm2) is applied to emit light at a brightness of approximately 1000 cd / m2. As can be seen from Figure 36, the emission spectra of these light-emitting devices have a peak near 457 nm, which all originate from the emission of 3,10PCA2Nbf(IV)-O2 contained in the light-emitting layer 913.

[0383] Next, reliability tests were performed on the light-emitting device 5 and the reference light-emitting device 6. Figure 37 shows the results of the reliability tests. In Figure 37, the vertical axis represents the normalized brightness (%) when the initial brightness is 100%, and the horizontal axis represents the driving time (h) of the device. Note that the reliability test was performed using a constant current density drive test, that is, the brightness change was measured at a constant current density of 50 mA / cm2 at room temperature. As can be seen from the results shown in Figure 37, the light-emitting device 5, which was exposed to N2 after the formation of the electron transport layer 914-2, exhibits the same high reliability as the reference light-emitting device 6, which was not exposed to nitrogen atmosphere (N2 exposure) even once during the fabrication process of the light-emitting device. Therefore, in the formation of the EL layer of the blue fluorescent light-emitting device, as long as it is after the formation of functional layers such as the electron transport layer 914, N2 exposure is unlikely to affect the reliability of the light-emitting device. As long as the functional layers such as the electron transport layer 914 are formed, atmospheric exposure and pattern formation using photolithography can be performed. In other words, in the fabrication of multiple light-emitting devices, patterning using photolithography can be performed after the formation of functional layers such as electron transport layers. Furthermore, the subsequently formed functional layers can be used in the formation of common layers across multiple light-emitting devices, thereby simplifying the manufacturing process. Example 3

[0384] In this embodiment, the device structure, manufacturing method, and characteristics of a red phosphorescent light-emitting device 7, manufactured as an embodiment of the present invention, are described. In the light-emitting device 7, the surface of the electron transport layer 914-2 is temporarily exposed to a nitrogen atmosphere (dew point around -80°C, moisture concentration: 0.5 ppm, oxygen concentration: 3 ppm) for 1 hour for N2 exposure treatment, and then the electron injection layer 915, the second electrode 903, and the capping layer 904 are formed sequentially. Note that, for comparison of device characteristics, a reference light-emitting device 8 is manufactured without any exposure to a nitrogen atmosphere (N2 exposure). Figure 23 shows the device structure of the light-emitting device used in this embodiment, and Table 3 shows the specific structure. In addition, the chemical formulas of the materials used in this embodiment are shown below. Furthermore, the device is manufactured in the same manner as in Example 1.

[0385]

[0386] [Chemical Formula 5]

[0387] In the above chemical formula, 9-[(3'-dibenzothiophene-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furano[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr) is shown.

[0388] <<Operating Characteristics of Light-Emitting Devices>> The operating characteristics of each manufactured light-emitting device were measured. These measurements were performed at room temperature. Furthermore, as a result of the operating characteristics of each light-emitting device, Figure 38 shows the luminance-current density characteristics, Figure 39 shows the luminance-voltage characteristics, Figure 40 shows the current efficiency-luminance characteristics, and Figure 41 shows the current density-voltage characteristics. Note that luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (manufactured by Topcon, SR-UL1R).

[0389] As can be seen from the above results, the light-emitting device 7 shown in this embodiment has the same good luminous efficiency as the reference light-emitting device 8 in the initial characteristics shown in Figures 38 to 41.

[0390] Figure 42 shows the emission spectra of each light-emitting device when a current density (10 mA / cm2 to 20 mA / cm2) is applied to emit light at a brightness of approximately 1000 cd / m2. As can be seen from Figure 42, the emission spectra of these light-emitting devices have a peak near 624 nm, which all originate from the emission of the red phosphorescent dopant OCPG-006 contained in the light-emitting layer 913.

[0391] Next, reliability tests were performed on the light-emitting device 7 and the reference light-emitting device 8. Figure 43 shows the results of the reliability tests. In Figure 43, the vertical axis represents the normalized brightness (%) when the initial brightness is 100%, and the horizontal axis represents the driving time (h) of the device. Note that the reliability test was performed using a constant current density drive test, that is, the brightness change was measured at a constant current density of 50 mA / cm2 at room temperature. As can be seen from the results shown in Figure 43, the light-emitting device 7, which was exposed to N2 after the formation of the electron transport layer 914-2, exhibits the same high reliability as the reference light-emitting device 8, which was not exposed to nitrogen atmosphere (N2 exposure) even once during the fabrication process of the light-emitting device. Therefore, in the formation of the EL layer of the red phosphorescent light-emitting device, as long as the functional layers such as the electron transport layer 914 are formed, N2 exposure is unlikely to affect the reliability of the light-emitting device. From this result, it can be seen that atmospheric exposure and pattern formation using photolithography can be performed as long as the functional layers such as the electron transport layer 914 are formed. In other words, in the fabrication of multiple light-emitting devices, patterning using photolithography can be performed after the formation of functional layers such as electron transport layers. Furthermore, the subsequently formed functional layers can be used in the formation of common layers across multiple light-emitting devices, thereby simplifying the manufacturing process. Example 4

[0392] In this embodiment, the device structure, manufacturing method, and characteristics of a green phosphorescent light-emitting device 9, which is a light-emitting device manufactured according to an embodiment of the present invention, are described. In the light-emitting device 9, the surface of the electron transport layer 914-2 is temporarily exposed to a nitrogen atmosphere (dew point around -80°C, moisture concentration: 0.5 ppm, oxygen concentration: 3 ppm) for 1 hour for N2 exposure treatment, and then the electron injection layer 915, the second electrode 903, and the capping layer 904 are formed sequentially. Note that, in order to compare device characteristics, a reference light-emitting device 10 is manufactured without any exposure to a nitrogen atmosphere (N2 exposure). FIG23 shows the device structure of the light-emitting device used in this embodiment, and Table 4 shows the specific structure. In addition, the chemical formulas of the materials used in this embodiment are shown below. Furthermore, the device is manufactured in the same manner as in Example 1.

[0393]

[0394] [Chemical Formula 6]

[0395] In the above chemical formula, 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophene-4-yl)phenyl]-[1]benzofurano[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), [2-d3-methyl-(2-pyridyl-κN)benzofurano[2,3-b]pyridin-κC]bis[2-(2-pyridyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(mbfpypy-d3)]), and 9-phenyl-9H-3-(9-phenyl-9H-carbazole-3-yl)carbazole (abbreviation: PCCP) are shown.

[0396] <<Operating Characteristics of Light-Emitting Devices>> The operating characteristics of each manufactured light-emitting device were measured. These measurements were performed at room temperature (atmosphere maintained at 25°C). Furthermore, as a result of the operating characteristics of each light-emitting device, Figure 44 shows the luminance-current density characteristics, Figure 45 shows the luminance-voltage characteristics, Figure 46 shows the current efficiency-luminance characteristics, and Figure 47 shows the current density-voltage characteristics. Note that luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (manufactured by Topcon, SR-UL1R).

[0397] As can be seen from the above results, the light-emitting device 9 shown in this embodiment has the same good luminous efficiency as the reference light-emitting device 10 in the initial characteristics shown in Figures 44 to 47.

[0398] Figure 48 shows the emission spectra of each light-emitting device when a current density (10 mA / cm2 to 20 mA / cm2) is applied to emit light at a brightness of approximately 1000 cd / m2. As can be seen from Figure 48, the emission spectra of these light-emitting devices have a peak near 528 nm, which all originate from the luminescence of the green phosphorescent dopant [Ir(ppy)2(mbfpypy-d3)] contained in the light-emitting layer 913.

[0399] Next, reliability tests were performed on the light-emitting device 9 and the reference light-emitting device 10. Figure 49 shows the results of the reliability tests. In Figure 49, the vertical axis represents the normalized brightness (%) when the initial brightness is 100%, and the horizontal axis represents the driving time (h) of the device. Note that the reliability test was performed using a constant current density drive test, that is, the brightness change was measured at a constant current density of 50 mA / cm2 at room temperature. As can be seen from the results shown in Figure 49, the light-emitting device 9, which was exposed to N2 after the formation of the electron transport layer 914-2, exhibits the same high reliability as the reference light-emitting device 10, which was not exposed to nitrogen atmosphere (N2 exposure) even once during the fabrication process of the light-emitting device. Therefore, in the formation of the EL layer of the green phosphorescent light-emitting device, as long as it is after the formation of functional layers such as the electron transport layer 914, N2 exposure is unlikely to affect the reliability of the light-emitting device. As can be seen from the above results, atmospheric exposure and pattern formation using photolithography can be performed after the formation of functional layers such as the electron transport layer 914. In other words, in the fabrication of multiple light-emitting devices, patterning using photolithography can be performed after the formation of functional layers such as electron transport layers. Furthermore, the subsequently formed functional layers can be used in the formation of common layers across multiple light-emitting devices, thereby simplifying the manufacturing process. Example 5

[0400] In this embodiment, the device structure, manufacturing method, and characteristics of light-emitting devices 11 and 12, which are red phosphorescent light-emitting devices manufactured as an embodiment of the present invention, will be described. In light-emitting device 11, after forming electron transport layer 914-2, patterning using photolithography is performed, and then electron injection layer 915, second electrode 903, and capping layer 904 are formed sequentially. Furthermore, in light-emitting device 12, similarly to light-emitting device 100 described using FIG. 1B in Embodiment 1, after forming electron transport layer 914-2, patterning using photolithography is performed, and then insulating films protecting the sides (or ends) of hole injection layer 911, hole transport layer 912, light-emitting layer 913, electron transport layer 914-1, and electron transport layer 914-2 are formed. Note that, for comparison of device characteristics, a reference light-emitting device 13 without photolithography patterning is manufactured. FIG. 23 shows the device structure of the light-emitting device used in this embodiment, and Table 5 shows the specific structure. In addition, the chemical formulas of the materials used in this embodiment are shown below.

[0401]

[0402] [Chemical Formula 7]

[0403] In the above chemical formula, 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoline (abbreviation: 2mpPCBPDBq) and bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedione-κ2O,O')iridium(III) (abbreviation: Ir(dmdppr-P)2(dibm)) are shown.

[0404] <<Operating Characteristics of Light-Emitting Devices>> The operating characteristics of each manufactured light-emitting device were measured. These measurements were performed at room temperature. Furthermore, as a result of the operating characteristics of each light-emitting device, Figure 50 shows the luminance-current density characteristics, Figure 51 shows the luminance-voltage characteristics, Figure 52 shows the current efficiency-luminance characteristics, Figure 53 shows the current density-voltage characteristics, Figure 54 shows the power efficiency-luminance characteristics, and Figure 55 shows the external quantum efficiency-luminance characteristics. Note that luminance, CIE chromaticity, and emission spectrum were measured at room temperature using a spectroradiometer (manufactured by Topcon, SR-UL1R).

[0405] As can be seen from the above results, the light-emitting device 11 and the light-emitting device 12 formed by using the photolithography method have good initial characteristics.

[0406] In the brightness-voltage characteristics shown in Figure 51, the voltage of the light-emitting device 11 is higher than that of the reference light-emitting device 13, while the voltage of the light-emitting device 12 is equal to that of the reference light-emitting device 13. It can be seen that by forming an insulating film on the sides (or ends) of the hole injection layer 911, hole transport layer 912, light-emitting layer 913, electron transport layer 914-1, and electron transport layer 914-2 after pattern formation using photolithography, the voltage of the light-emitting device can be suppressed from increasing.

[0407] Figure 56 shows the emission spectra of each light-emitting device when a current density (10 mA / cm2 to 20 mA / cm2) is applied to emit light at a brightness of approximately 1000 cd / m2. As can be seen from Figure 56, the emission spectra of these light-emitting devices have a peak near 635 nm, which all originate from the emission of the red phosphorescent dopant Ir(dmdppr-P)2(dibm) contained in the light-emitting layer 913.

[0408] Next, reliability tests were performed on light-emitting device 11, light-emitting device 12, and comparison light-emitting device 13. Figure 57 shows the results of the reliability tests. In Figure 57, the vertical axis represents the normalized brightness (%) when the initial brightness is 100%, and the horizontal axis represents the driving time (h) of the device. Note that a constant current density driving test was performed as a reliability test, that is, the brightness change was measured at a constant current density of 50 mA / cm2 at room temperature.

[0409] As shown in Figure 57, the reliability of light-emitting devices 11 and 12 is not significantly different from that of the reference light-emitting device 13. Therefore, in the formation of the EL layer of the light-emitting device, as long as it is performed after the formation of functional layers such as the electron transport layer 914, even if patterning using photolithography is performed, it is not likely to affect the reliability of the light-emitting device. In other words, in the manufacturing of multiple light-emitting devices, patterning using photolithography can be performed after the formation of functional layers such as the electron transport layer, and the functional layers formed thereafter can be used in the formation of a common layer in multiple light-emitting devices, thereby simplifying the process. [Simplified Explanation of the Diagram]

[0027] [Figures 1A] to [Figures 1C] are diagrams illustrating the structure of the light-emitting device according to the embodiment; [Figures 2A] to [Figures 2E] are diagrams illustrating the structure of the light-emitting device according to the embodiment; [Figures 3A] and [Figures 3B] are diagrams illustrating the structure of the light-emitting device according to the embodiment; [Figures 4A] and [Figures 4B] are diagrams illustrating a method for manufacturing the light-emitting device according to the embodiment; [Figures 5A] to [Figures 5C] are diagrams illustrating a method for manufacturing the light-emitting device according to the embodiment; [Figures 6A] to [Figures 6C] are diagrams illustrating a method for manufacturing the light-emitting device according to the embodiment; [Figures 7A] and [Figures 7B] are diagrams illustrating a method for manufacturing the light-emitting device according to the embodiment; [Figure 8] is a diagram illustrating a light-emitting device according to the embodiment; [Figures 9A] and [Figures 9B] are diagrams illustrating a light-emitting device and a light-emitting apparatus according to the embodiment; [Figure 10] is a diagram illustrating a light-emitting device according to the embodiment; [Figures 11A] to [Figures 11C] are diagrams illustrating a method for manufacturing the light-emitting device according to the embodiment; [Figure 12A] and [Figure 12B] are diagrams illustrating a method for manufacturing a light-emitting device according to an embodiment; [Figure 13] is a diagram illustrating a light-emitting device according to an embodiment; [Figure 14A] and [Figure 14B] are diagrams illustrating a light-emitting device according to an embodiment; [Figure 15A] and [Figure 15B] are diagrams illustrating a light-emitting device according to an embodiment; [Figure 16A] and [Figure 16B] are diagrams illustrating a light-emitting device according to an embodiment; [Figure 17A] and [Figure 17B] are diagrams illustrating a light-emitting device according to an embodiment; [Figure 18A] to [Figure 18E] are diagrams illustrating an electronic device according to an embodiment; [Figure 19A] to [Figure 19E] are diagrams illustrating an electronic device according to an embodiment; [Figure 20A] and [Figure 20B] are diagrams illustrating an electronic device according to an embodiment; [Figure 21A] and [Figure 21B] are diagrams illustrating an electronic device according to an embodiment; [Figure 22] is a diagram illustrating an electronic device according to an embodiment. [Figure 23] is a diagram showing the structure of the light-emitting devices used in Examples 1 to 4; [Figure 24] is the brightness-current density characteristic of light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4; [Figure 25] is the brightness-voltage characteristic of light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4; [Figure 26] is the current efficiency-brightness characteristic of light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4; [Figure 27] is the current density-voltage characteristic of light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4; [Figure 28] is the blue index-brightness characteristic of light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4; [Figure 29] is the emission spectrum of light-emitting device 1, light-emitting device 2, comparison light-emitting device 3, and reference light-emitting device 4;[Figure 30] is a graph showing the reliability of light-emitting device 1, light-emitting device 2, comparative light-emitting device 3, and reference light-emitting device 4; [Figure 31] is the brightness-current density characteristic of light-emitting device 5 and reference light-emitting device 6; [Figure 32] is the brightness-voltage characteristic of light-emitting device 5 and reference light-emitting device 6; [Figure 33] is the current efficiency-brightness characteristic of light-emitting device 5 and reference light-emitting device 6; [Figure 34] is the current density-voltage characteristic of light-emitting device 5 and reference light-emitting device 6; [Figure 35] is the blue index-brightness characteristic of light-emitting device 5 and reference light-emitting device 6; [Figure 36] is the emission spectrum of light-emitting device 5 and reference light-emitting device 6; [Figure 37] is a graph showing the reliability of light-emitting device 5 and reference light-emitting device 6; [Figure 38] is the brightness-current density characteristic of light-emitting device 7 and reference light-emitting device 8; [Figure 39] is the brightness-voltage characteristic of light-emitting device 7 and reference light-emitting device 8; [Figure 40] is the current efficiency-brightness characteristic of light-emitting device 7 and reference light-emitting device 8. [Figure 41] shows the current density-voltage characteristics of light-emitting device 7 and reference light-emitting device 8; [Figure 42] shows the emission spectra of light-emitting device 7 and reference light-emitting device 8; [Figure 43] shows the reliability of light-emitting device 7 and reference light-emitting device 8; [Figure 44] shows the luminance-current density characteristics of light-emitting device 9 and reference light-emitting device 10; [Figure 45] shows the luminance-voltage characteristics of light-emitting device 9 and reference light-emitting device 10; [Figure 46] shows the current efficiency-luminance characteristics of light-emitting device 9 and reference light-emitting device 10; [Figure 47] shows the current density-voltage characteristics of light-emitting device 9 and reference light-emitting device 10; [Figure 48] shows the emission spectra of light-emitting device 9 and reference light-emitting device 10; [Figure 49] shows the reliability of light-emitting device 9 and reference light-emitting device 10; [Figure 50] shows the luminance-current density characteristics of light-emitting device 11, light-emitting device 12 and reference light-emitting device 13; [Figure 51] shows the luminance-voltage characteristics of light-emitting device 11, light-emitting device 12 and reference light-emitting device 13. [Figure 52] shows the current efficiency-luminance characteristics of light-emitting devices 11, 12, and 13; [Figure 53] shows the current density-voltage characteristics of light-emitting devices 11, 12, and 13; [Figure 54] shows the power efficiency-luminance characteristics of light-emitting devices 11, 12, and 13; [Figure 55] shows the external quantum efficiency-luminance characteristics of light-emitting devices 11, 12, and 13; [Figure 56] shows the emission spectra of light-emitting devices 11, 12, and 13; [Figure 57] shows the reliability of light-emitting devices 11, 12, and 13.

Claims

1. A light-emitting device, comprising: a second electrode with an EL layer sandwiched on a first electrode, wherein: The EL layer includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. The hole injection layer is on the first electrode, the hole transport layer is on the hole injection layer, the light-emitting layer is on the hole transport layer, the electron transport layer is on the light-emitting layer, an insulating layer is in contact with the sides of the light-emitting layer and the electron transport layer, the electron injection layer is on the electron transport layer and the insulating layer, and the electron injection layer is in contact with the electron transport layer and the insulating layer.

2. A light-emitting device, comprising: a second electrode with an EL layer sandwiched on a first electrode, wherein: The EL layer includes a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. The hole injection layer is on the first electrode, the hole transport layer is on the hole injection layer, the light-emitting layer is on the hole transport layer, the electron transport layer is on the light-emitting layer, an insulating layer is in contact with the sides of the hole injection layer, the light-emitting layer, and the electron transport layer, the electron injection layer is on the electron transport layer and the insulating layer, the electron injection layer is in contact with the electron transport layer and the insulating layer, and the second electrode is on the insulating layer.

3. The light-emitting device as requested in item 1 or 2, wherein, The electron-injection layer comprises a composite material consisting of a mixture of organic compounds and electron donors, or a composite material consisting of a mixture of organic compounds and any one of alkali metals, alkaline earth metals, rare earth metals, and metals belonging to Group 5, Group 7, Group 9, Group 11, or Group 13 of the periodic table.

4. A light-emitting device comprising: a light-emitting device as claimed in claim 1 or 2; and at least one of a transistor and a substrate.

5. An electronic device comprising: a light-emitting device as claimed in claim 4; and at least one of a sensor, an operation button, a speaker, and a microphone.

6. A lighting device comprising: a light-emitting device as claimed in claim 4; and a housing.

7. A light-emitting device comprising adjacent first light-emitting devices and second light-emitting devices, wherein: The first light-emitting device includes a second electrode with a first EL layer sandwiched on a first electrode. The first EL layer includes a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, and an electron injection layer. The first hole injection layer is on the first electrode. The first hole transport layer is on the first hole injection layer. The first light-emitting layer is on the first hole transport layer. The first electron transport layer is on the first light-emitting layer. A first insulating layer is in contact with the sides of the first light-emitting layer and the first electron transport layer. The electron injection layer is on the first electron transport layer. The second light-emitting device includes a second electrode with a second EL layer sandwiched on a third electrode. The second EL layer includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and the electron injection layer. The second hole injection layer is on the third electrode. The second hole transport layer is on the second hole injection layer. The second light-emitting layer is on the second hole transport layer. The second electron transport layer is on the second light-emitting layer. A second insulating layer is in contact with the sides of the second light-emitting layer and the second electron transport layer. The electron injection layer is on the first electron transport layer and the second electron transport layer, and the electron injection layer is in contact with the first electron transport layer, the second electron transport layer, the first insulating layer and the second insulating layer.

8. A light-emitting device comprising adjacent first light-emitting devices and second light-emitting devices, wherein: The first light-emitting device includes a second electrode with a first EL layer sandwiched on a first electrode. The first EL layer includes a first hole injection layer, a first hole transport layer, a first light-emitting layer, a first electron transport layer, and an electron injection layer. The first hole injection layer is on the first electrode. The first hole transport layer is on the first hole injection layer. The first light-emitting layer is on the first hole transport layer. The first electron transport layer is on the first light-emitting layer. The electron injection layer is on the first electron transport layer. The second light-emitting device includes a second electrode with a second EL layer sandwiched on a third electrode. The second EL layer includes a second hole injection layer, a second hole transport layer, a second light-emitting layer, a second electron transport layer, and the electron injection layer. The second hole injection layer is on the third electrode. The second hole transport layer is on the second hole injection layer. The second light-emitting layer is on the second hole transport layer. The second electron transport layer is on the second light-emitting layer. The electron injection layer is on the first electron transport layer and the second electron transport layer. The electron injection layer is in contact with the first electron transport layer, the second electron transport layer, and the insulating layer, and the insulating layer is also in contact with the side of the first hole injection layer, the side of the first light-emitting layer, the side of the first electron transport layer, the side of the second hole injection layer, the side of the second light-emitting layer, and the side of the second electron transport layer.

9. The light-emitting device as claimed in item 7 or 8, wherein, The second electrode is located on the side of the first light-emitting layer and the second light-emitting layer, separated by the electron injection layer.

10. The light-emitting device as claimed in claim 7 or 8, wherein, The second electrode is located on the side of the first electron transport layer, the second electron transport layer, the first light-emitting layer, and the second light-emitting layer, separated by the electron injection layer.

11. The light-emitting device as claimed in item 7 or 8, wherein, The electron-injection layer comprises a composite material consisting of a mixture of organic compounds and electron donors, or a composite material consisting of a mixture of organic compounds and any one of alkali metals, alkaline earth metals, rare earth metals, or metals belonging to Group 5, Group 7, Group 9, Group 11, or Group 13 of the periodic table.

12. The light-emitting device as claimed in claim 7, wherein, The electron injection layer is on the first insulating layer.

13. The light-emitting device as claimed in claim 8, wherein, The electron injection layer is on the insulating layer.

14. An electronic device comprising: a light-emitting device as claimed in claim 7 or 8; and at least one of a sensor, an operation button, a speaker, and a microphone.

15. A lighting device comprising: a light-emitting device as claimed in claim 7 or 8; and a housing.

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