Light-emitting device and light-emitting apparatus

Abstract

To provide a light-emitting device having high heat resistance in a manufacturing process.SOLUTION: The light-emitting device has an EL layer between an anode and a cathode. The EL layer has at least a light-emitting layer and an electron transport layer. The electron transport layer has a first electron transport layer in contact with the light-emitting layer, and a second electron transport layer in contact with the first electron transport layer. The first electron transport layer contains a first heteroaromatic compound having at least one heteroaromatic ring. The second electron transport layer contains a second heteroaromatic compound having at least one heteroaromatic ring and different from the first heteroaromatic compound. The first heteroaromatic compound has a temperature difference between the crystallization temperature (Tpc) in a powder state and the crystallization temperature (Ttc) in a thin film state of 20°C or less. The second heteroaromatic compound has a difference between the crystallization temperature (Tpc) in a powder state and the crystallization temperature (Ttc) in a thin film state of 100°C or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] One aspect of the present invention relates to light-emitting devices, light-emitting apparatuses, light-receiving apparatuses, display devices, electronic devices, lighting apparatuses, and electronic devices. However, one aspect of the present invention is not limited to the above-mentioned technical field. The technical field of one aspect of the invention disclosed herein relates to a product, a method, or a method of manufacture. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. More specifically, examples of the technical field of one aspect of the present invention disclosed herein include semiconductor devices, display devices, liquid crystal display devices, light-emitting devices, lighting apparatuses, energy storage devices, memory devices, imaging devices, methods for driving them, or methods for manufacturing them. [Background technology]

[0002] The practical application of light-emitting devices (organic EL devices) that utilize electroluminescence (EL) using organic compounds is progressing. The basic structure of these light-emitting devices is an organic compound layer (EL layer) containing a light-emitting material sandwiched between a pair of electrodes. By applying a voltage to this device, carriers are injected, and by utilizing the recombination energy of these carriers, light emission can be obtained from the light-emitting material.

[0003] Because these light-emitting devices are self-emissive, using them as pixels in a display offers advantages over liquid crystal displays, such as higher visibility and the elimination of the need for a backlight, making them suitable as flat-panel display elements. Furthermore, displays using such light-emitting devices can be manufactured to be thin and lightweight, which is a significant advantage. Another characteristic is their extremely fast response speed.

[0004] Furthermore, since these light-emitting devices can form a light-emitting layer continuously in two dimensions, they can produce light in a planar manner. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs and LEDs, or line light sources such as fluorescent lamps, and therefore has high value as a planar light source that can be applied to lighting and other applications.

[0005] While displays and lighting devices using light-emitting devices are suitable for various electronic devices, research and development are underway to find light-emitting devices with even better characteristics.

[0006] Various methods are known for manufacturing light-emitting devices, but one method for creating high-resolution light-emitting devices is to form a light-emitting layer without using a fine metal mask. One example of this is a method for manufacturing an organic EL display (Patent Document 1) which includes the steps of: depositing a first luminescent organic material containing a mixture of a host material and a dopant material on top of an electrode array including first and second pixel electrodes formed on top of an insulating substrate to form a first light-emitting layer as a continuous film extending over a display area including the electrode array; irradiating the portion of the first light-emitting layer located above the first pixel electrode with ultraviolet light without irradiating the portion of the first light-emitting layer located above the first pixel electrode with ultraviolet light; depositing a second luminescent organic material containing 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 extending over a display area; and forming a counter electrode on top of the second light-emitting layer.

[0007] Furthermore, as one example of an organic EL device, Non-Patent Document 1 discloses a method for manufacturing an organic optoelectronic device using standard UV photolithography (Non-Patent Document 1). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-160473

Non-Patent Literature

[0009]

Non-Patent Literature 1

Summary of the Invention

Problems to be Solved by the Invention

[0010] One aspect of the present invention aims to provide a light-emitting device with high heat resistance. Another aspect of the present invention aims to provide a light-emitting device with high heat resistance in the manufacturing process. Or, another aspect of the present invention aims to provide a highly reliable light-emitting device. Or, one aspect of the present invention aims to provide a light-emitting device, a light-emitting device, an electronic device, a display device, and an electronic device with low power consumption, respectively. Or, one aspect of the present invention aims to provide a light-emitting device, a light-emitting device, an electronic device, a display device, and an electronic device with low power consumption and high reliability.

[0011] [[ID=2​​​​​​​One aspect of the present invention has an EL layer between an anode and a cathode. The EL layer has at least a light-emitting layer and an electron transport layer. The electron transport layer has a first electron transport layer in contact with the light-emitting layer and a second electron transport layer in contact with the first electron transport layer. The first electron transport layer has a first heteroaromatic compound having at least one heteroaromatic ring. The second electron transport layer has at least one heteroaromatic ring and a second heteroaromatic compound different from the first heteroaromatic compound. The first heteroaromatic compound has a temperature difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin-film state within 20 °C. The second heteroaromatic compound has a difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin-film state within 100 °C. It is a light-emitting device.

[0013] Note that the crystallization temperature (Tpc) in the powder state as described above refers to the crystallization temperature obtained as a result of performing thermal analysis (differential scanning calorimetry) using a powder (solid) of an organic compound.

[0014] Also, the crystallization temperature (Ttc) in the thin-film state as described above is defined in this specification as the temperature at which a change in film quality is observed when a thin film formed by vapor-depositing a powder (solid) of an organic compound is heated. When the film quality changes, a part or all of the transparent film changes to white (or the color of the material) and the transparency decreases. This state is observed with a microscope or the like to determine the temperature at which the film quality changes.

[0015] Also, in the above configuration, the heteroaromatic ring preferably has any one of a pyridine ring, a diazine ring, a triazine ring, or a polyazole ring.

[0016] Also, in the above configuration, the heteroaromatic ring preferably has a condensed heteroaromatic ring having a condensed ring structure.

[0017] Furthermore, in the above configuration, the condensed heteroaromatic ring is preferably one of the following: a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phlodiazine ring, or a benzimidazole ring.

[0018] Furthermore, in the above configuration, the heteroaromatic ring is preferably one of the following: a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, a pyridine ring, a phenanthroline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a benzimidazole ring, a benzoflopyrimidine ring, or a benzoflopyrazine ring.

[0019] Furthermore, in addition to the light-emitting devices described above, cases in which a layer containing an organic compound (e.g., a cap layer) is in contact with the electrode are also included as light-emitting devices and are included in the present invention.

[0020] Another aspect of the present invention is a light-emitting device having a light-emitting device, transistor, or substrate having any of the above-described configurations.

[0021] Another aspect of the present invention comprises an adjacent first light-emitting device and a second light-emitting device, wherein the first light-emitting device has a second electrode sandwiching a first EL layer on a first electrode, the first EL layer comprises at least a first light-emitting layer, a first electron transport layer, a second electron transport layer, and a first electron injection layer, the first light-emitting layer having the first electron transport layer and the second electron transport layer, and the sides of the first light-emitting layer, the sides of the first electron transport layer, and the sides of the second electron transport layer are in contact with each other. The second light-emitting device has a first insulating layer, a first electron injection layer on a second electron transport layer, the first insulating layer is located between the side surface of the first light-emitting layer, the side surface of the first electron transport layer, and the side surface of the second electron transport layer and the first electron injection layer, the second light-emitting device has a second electrode sandwiched between a second EL layer on a third electrode, the second EL layer has at least a second light-emitting layer, a third electron transport layer, a fourth electron transport layer and a second electron injection layer, and the second light-emitting device has a third electron transport layer and The second electron transport layer has a fourth electron transport layer, and a second insulating layer is in contact with the sides of the second light-emitting layer, the sides of the third electron transport layer, and the sides of the fourth electron transport layer, and a first electron injection layer is on the fourth electron transport layer, the second insulating layer is located between the sides of the second light-emitting layer, the sides of the third electron transport layer, and the sides of the fourth electron transport layer and the first electron injection layer, and the first electron transport layer and the third electron transport layer have a first heteroaromatic compound having at least one heteroaromatic ring, and the second electron The electron transport layer and the fourth electron transport layer each have at least one heteroaromatic ring and a second heteroaromatic compound different from the first heteroaromatic compound, wherein the first heteroaromatic compound has a temperature difference of 20°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state, and the second heteroaromatic compound has a temperature difference of 100°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state.

[0022] In the above configuration, it is preferable that the heteroaromatic ring has one of the following skeletons: pyridine, diazine, triazine, or polyazole.

[0023] Furthermore, in the above configuration, it is preferable that the heteroaromatic ring has a fused heteroaromatic ring structure.

[0024] Furthermore, in the above configuration, the condensed heteroaromatic ring is preferably one of the following: a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phlodiazine ring, or a benzimidazole ring.

[0025] Another aspect of the present invention is an electronic device having a light-emitting device, a detection unit, an input unit, or a communication unit having any of the above-described configurations.

[0026] Another aspect of the present invention is a lighting device having a light-emitting device and a housing having any of the above-described configurations.

[0027] Furthermore, one aspect of the present invention includes a light-emitting device or a light-receiving device having a light-emitting device, and further includes an illumination device having a light-emitting device or a light-receiving device. Accordingly, in this specification, a light-emitting device or a light-receiving device refers to an image display device or a light source (including an illumination device). In addition, modules to which connectors such as FPC (Flexible printed circuit) or TCP (Tape Carrier Package) are attached, modules to which a printed circuit board is provided at the end of a TCP, or modules to which an IC (Integrated Circuit) is directly mounted on a light-emitting device using the COG (Chip On Glass) method are all included as light-emitting devices.

[0028] In this specification, the terms "source" and "drain" of a transistor are interchangeable depending on 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. For convenience, this specification sometimes describes the connection relationships of a transistor assuming that the source and drain are fixed, but in reality, the terms "source" and "drain" are interchangeable according to the potential relationship described above.

[0029] In this specification, the source of a transistor refers to the source region, which is part of the semiconductor film that functions as the active layer, or the source electrode connected to the semiconductor film. Similarly, the drain of a transistor refers to the drain region, which is part of the semiconductor film, or the drain electrode connected to the semiconductor film. The gate refers to the gate electrode.

[0030] In this specification, a state in which transistors are connected in series means, for example, a state in which only one source or drain of the first transistor is connected to only one source or drain of the second transistor. A state in which transistors are connected in parallel means a state in which one source or drain of the first transistor is connected to one source or drain of the second transistor, and the other source or drain of the first transistor is connected to the other source or drain of the second transistor.

[0031] In this specification, "connection" means an electrical connection, corresponding to a state in which current, voltage, or potential can be supplied or transmitted. Therefore, a connected state does not necessarily refer to a direct connection, but also includes a state indirectly connected through circuit elements such as wiring, resistors, diodes, and transistors, so that current, voltage, or potential can be supplied or transmitted.

[0032] In this specification, even when components that appear independent in a circuit diagram are connected, in reality, a single conductive film may combine the functions of multiple components, for example, when a portion of the wiring functions as an electrode. In this specification, "connection" includes such cases where a single conductive film combines the functions of multiple components. [Effects of the Invention]

[0033] One aspect of the present invention can provide a light-emitting device with high heat resistance. Another aspect of the present invention can provide a light-emitting device with high heat resistance in the manufacturing process. Alternatively, another aspect of the present invention can provide a highly reliable light-emitting device. Alternatively, one aspect of the present invention can provide a light-emitting device, light-emitting apparatus, electronic device, display device, and electronic device with low power consumption. Alternatively, one aspect of the present invention can provide a light-emitting device, light-emitting apparatus, electronic device, display device, electronic device, and lighting apparatus with low power consumption and high reliability.

[0034] Furthermore, the description of these effects does not preclude the existence of other effects. Moreover, one aspect of the present invention does not necessarily have to possess all of these effects. Other effects will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other effects from the description in the specification, drawings, and claims. [Brief explanation of the drawing]

[0035] [Figure 1] Figures 1(A) to 1(C) illustrate the configuration of a light-emitting device according to an embodiment. [Figure 2] Figures 2(A) to 2(E) illustrate the configuration of a light-emitting device according to an embodiment. [Figure 3] Figures 3(A) to 3(D) illustrate a light-emitting device according to an embodiment. [Figure 4]Figures 4(A) to 4(C) illustrate a method for manufacturing a light-emitting device according to an embodiment. [Figure 5] Figures 5(A) to 5(C) illustrate a method for manufacturing a light-emitting device according to an embodiment. [Figure 6] Figures 6(A) to 6(C) illustrate a method for manufacturing a light-emitting device according to an embodiment. [Figure 7] Figures 7(A) to 7(C) illustrate a method for manufacturing a light-emitting device according to an embodiment. [Figure 8] Figure 8 is a diagram illustrating a light-emitting device according to an embodiment. [Figure 9] Figures 9(A) to 9(F) illustrate the apparatus and pixel arrangement according to the embodiment. [Figure 10] Figures 10(A) to 10(C) illustrate the pixel circuit according to the embodiment. [Figure 11] Figures 11(A) and 11(B) illustrate a light-emitting device according to an embodiment. [Figure 12] Figures 12(A) to 12(E) illustrate the electronic device according to the embodiment. [Figure 13] Figures 13(A) to 13(E) illustrate the electronic device according to the embodiment. [Figure 14] Figures 14(A) and 14(B) illustrate an electronic device according to an embodiment. [Figure 15] Figures 15(A) and 15(B) illustrate a lighting device according to an embodiment. [Figure 16] Figure 16 is a diagram illustrating a lighting device according to an embodiment. [Figure 17] Figure 17 illustrates the light-emitting device and light-receiving device according to the embodiment. [Figure 18] Figure 18 is a photograph relating to an embodiment. [Figure 19] Figure 19 is a photograph relating to an example. [Figure 20] Figure 20 is a photograph relating to an example. [Figure 21] Figure 21 is a diagram illustrating the configuration of a light-emitting device according to an embodiment. [Figure 22] Figure 22 shows the current-voltage characteristics of light-emitting device 1 and light-emitting device 2. [Figure 23] Figure 23 shows the current efficiency-luminance characteristics of light-emitting device 1 and light-emitting device 2. [Figure 24] Figure 24 shows the current-voltage characteristics of comparative light-emitting device 3 and comparative light-emitting device 4. [Figure 25] Figure 25 shows the current efficiency-luminance characteristics of comparative light-emitting device 3 and comparative light-emitting device 4. [Figure 26] Figure 26 shows the emission spectra of light-emitting device 1, light-emitting device 2, reference light-emitting device 3, and reference light-emitting device 4. [Modes for carrying out the invention]

[0036] The embodiments of the present invention will be described in detail below with reference to the drawings. However, it will be readily apparent to those skilled in the art that the present invention is not limited to the following description, and that its form and details can be modified in various ways without departing from the spirit and scope of the present invention. Accordingly, the present invention shall not be interpreted as being limited to the contents of the embodiments shown below.

[0037] (Embodiment 1) This embodiment describes a light-emitting device that is one aspect of the present invention. By using the device configuration shown in this embodiment, it is possible to provide a light-emitting device that is less susceptible to influences on its characteristics caused by processes including heat treatment during the manufacturing process, in other words, a light-emitting device with high heat resistance.

[0038] Figure 1(A) shows the structure of a light-emitting device 100 according to one embodiment of the present invention. As shown in Figure 1(A), the light-emitting device 100 has a first electrode 101 and a second electrode 102, and has an EL layer 103 in which a hole injection / transport layer 104, a light-emitting layer 113, a first electron transport layer 108-1, a second electron transport layer 108-2, and an electron injection layer 109 are sequentially stacked between the first electrode 101 and the second electrode 102. That is, the electron transport layer of the light-emitting device 100 has a structure in which the first electron transport layer 108-1 and the second electron transport layer 108-2 are stacked.

[0039] The first electron transport layer 108-1 comprises a heteroaromatic compound having at least one heteroaromatic ring. Note that heteroaromatic compounds are included in organic compounds. Furthermore, it is preferable that the heteroaromatic compound used in the first electron transport layer 108-1 has a temperature difference of 20°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state.

[0040] Furthermore, the second electron transport layer 108-2 has at least one heteroaromatic ring and contains a heteroaromatic compound different from the heteroaromatic compound used in the first electron transport layer 108-1. It is also preferable that the heteroaromatic compound used in the second electron transport layer 108-2 has a difference of 100°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state.

[0041] Furthermore, the heteroaromatic ring has one of the following: a pyridine ring, a diazine ring, a triazine ring, or a polyazole ring. The diazine ring includes pyrimidine rings, pyrazine rings, and pyridazine rings. Additionally, the heteroaromatic ring includes fused heteroaromatic rings having a fused ring structure.

[0042] Furthermore, examples of condensed heteroaromatic rings include quinoline rings, benzoquinoline rings, quinoxaline rings, dibenzoquinoxaline rings, quinazoline rings, benzoquinazoline rings, dibenzoquinazoline rings, phenanthroline rings, benzophrodiazine rings (e.g., benzoflopyrimidine rings and benzoflopyrazine rings), and benzimidazole rings. For example, quinoline rings, benzoquinoline rings, and phenanthroline rings contain the structure of a pyridine ring. Also, quinoxaline rings, dibenzoquinoxaline rings, and benzoflopyrazine rings contain the structure of a pyrazine ring. Furthermore, quinazoline rings, benzoquinazoline rings, dibenzoquinazoline rings, and benzoflopyrimidine rings contain the structure of a pyrimidine ring.

[0043] As heteroaromatic compounds that can be used in the first electron transport layer 108-1 and the second electron transport layer 108-2, specific examples of heteroaromatic compounds having the heteroaromatic ring described above, or heteroaromatic compounds having a condensed heteroaromatic ring, can be appropriately combined from the materials shown in Embodiment 2, in which the difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state falls within the range described above.

[0044] Furthermore, as heteroaromatic compounds that can be used in the first electron transport layer 108-1 or the second electron transport layer 108-2, one or more heteroaromatic compounds represented by the following structural formulas (101) to (116) can be used in combination, provided that the above-mentioned temperature conditions are met.

[0045] [ka]

[0046] [ka]

[0047] Figures 1(B) and 1(C) show an example of the specific structure of the light-emitting device 100 shown in Figure 1(A). Figure 1(B) shows a structure in which a hole injection / transport layer 104, a light-emitting layer 113, a first electron transport layer 108-1, a second electron transport layer 108-2, and an electron injection layer 109 are sequentially stacked on a first electrode 101. As can be seen from the cross-sectional view in Figure 1(B), the ends (or sides) of the hole injection / transport layer 104, light-emitting layer 113, first electron transport layer 108-1, and second electron transport layer 108-2 are inward from the ends (or sides) of the first electrode 101. Furthermore, the structure has such that the ends (or sides) of the hole injection / transport layer 104, the light-emitting layer 113, the first electron transport layer 108-1, and the second electron transport layer 108-2 are in contact with a part and ends (or sides) of the first electrode 101 and the insulating layer 107.

[0048] Furthermore, by providing the insulating layer 107, the edges (or sides) of the hole injection / transport layer 104, the edges (or sides) of the light-emitting layer 113, the edges (or sides) of the first electron transport layer 108-1, and the edges (or sides) of the second electron transport layer 108-2 can be protected. This suppresses damage to each layer during the manufacturing process and prevents electrical connections due to contact between different layers.

[0049] The electron injection layer 109 is part of the EL layer 103, but as shown in Figure 1(B), it has a different shape from the other layers of the EL layer 103 (hole injection / transport layer 104, light-emitting layer 113, first electron transport layer 108-1, and second electron transport layer 108-2). However, the electron injection layer 109 and the second electrode 102 can have the same shape. Since the electron injection layer 109 and the second electrode 102 can be layers common to multiple light-emitting devices, the manufacturing process of the light-emitting device 100 can be simplified and throughput can be improved.

[0050] Alternatively, the light-emitting device may have a structure as shown in Figure 1(C). On the first electrode 101, a hole injection / transport layer 104, a light-emitting layer 113, a first electron transport layer 108-1, a second electron transport layer 108-2, and an electron injection layer 109 are sequentially stacked, covering the first electrode 101. The ends of the hole injection / transport layer 104, the light-emitting layer 113, the first electron transport layer 108-1, and the second electron transport layer 108-2 are located outside the end (or side) of the first electrode 101 in the cross-sectional view of Figure 1(C). Furthermore, the ends of the hole injection / transport layer 104, the light-emitting layer 113, the first electron transport layer 108-1, and the second electron transport layer 108-2 are in contact with the insulating layer 107.

[0051] The insulating layer 107 is in contact with the ends (or sides) of the hole injection / transport layer 104, the ends (or sides) of the light-emitting layer 113, the ends (or sides) of the first electron transport layer 108-1, and the ends (or sides) of the second electron transport layer 108-2, respectively. The insulating layer 107 is also located between the ends (or sides) of the hole injection / transport layer 104, the ends (or sides) of the light-emitting layer 113, the ends (or sides) of the first electron transport layer 108-1, and the ends (or sides) of the second electron transport layer 108-2 and the second insulating layer 140. Furthermore, an electron injection layer 109 is provided on the second insulating layer 140, the insulating layer 107, and the second electron transport layer 108-2. The second insulating layer 140 can be made of an organic compound or an inorganic compound.

[0052] When an organic compound is used for the second insulating layer 140, for example, acrylic resin, polyimide resin, epoxy resin, polyamide resin, polyimidoamide resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used. A photosensitive resin may also be used. As the photosensitive resin, a positive-type material or a negative-type material can be used.

[0053] By using a photosensitive resin as the second insulating layer 140, the second insulating layer 140 can be fabricated solely through the exposure and development processes in the manufacturing process, thereby reducing the impact on other layers due to dry etching or wet etching. Furthermore, using a negative-type photosensitive resin is preferable because it may allow the photomask (exposure mask) used in other processes to be reused.

[0054] In the device structures shown in Figures 1(B) and 1(C), when a pattern is formed during the manufacturing process to shape a portion of the EL layer 103 into a desired form, heat is applied to the processed surface, and it may also be exposed to the atmosphere. This can lead to problems such as crystallization of the processed layer, potentially reducing the reliability and brightness of the light-emitting device. In contrast, the light-emitting device 100 shown in this embodiment 1 uses the surface of a highly heat-resistant electron transport layer (the surface after the second electron transport layer 108-2 is laminated on the first electron transport layer 108-1) as the processed surface during the manufacturing process, thereby suppressing crystallization of the electron transport layer that becomes the processed surface. In this case, since the electron injection layer 109, which is part of the EL layer 103, is formed after the electron transport layer is formed, the structure of the electron injection layer 109 is different from that of the other layers of the EL layer 103 (hole injection / transport layer 104, light-emitting layer 113, first electron transport layer 108-1, and second electron transport layer 108-2).

[0055] The light-emitting device 100 having the shape shown in Figures 1(B) and 1(C) is an example of a device structure that can be patterned by such a manufacturing method, but is not limited to this as long as it has a structure having a first electron transport layer 108-1 and a second electron transport layer 108-2. By having a device structure that is one aspect of the present invention, it is possible to provide a light-emitting device that suppresses a decrease in efficiency and a deterioration in reliability.

[0056] Note that the insulating layer 107 shown in Figures 1(B) and 1(C) may be omitted if unnecessary. For example, if the conductivity between the electron injection layer 109 and the hole injection / transport layer 104 is sufficiently small, the light-emitting device 100 may not have an insulating layer 107.

[0057] The materials that can be used as the first electrode 101, the second electrode 102, the hole injection / transport layer 104, the light-emitting layer 113, the electron injection layer 109, and the insulating layer 107 are materials that will be described in later embodiments.

[0058] The electron transport layers (108-1, 108-2) having a multilayer structure in the EL layer of the light-emitting device shown in this embodiment can improve the heat resistance of the light-emitting device. In other words, the electron transport layers (108-1, 108-2) having a multilayer structure can effectively suppress morphological changes due to thinning.

[0059] Furthermore, when the heteroaromatic compounds contained in the electron transport layers (108-1, 108-2) having the above-described layered structure have fused heteroaromatic rings as heteroaromatic rings, the thermophysical properties such as the glass transition temperature (Tg) and crystallization temperature (Tc) are improved compared to when the layer contains a large amount of heteroaromatic compounds that do not have fused heteroaromatic rings.

[0060] Even when a thin film (monofilm) is formed using only one type of heteroaromatic compound containing a condensed heteroaromatic ring, and a seemingly stable glassy state is achieved, it can be difficult to maintain this state due to strong intermolecular interactions. In other words, in a thin film (monofilm) formed using only one type of heteroaromatic compound, where the glassy state should be maintained at temperatures below Tg, crystallization that would not normally occur can be observed due to exposure to air or stimulation at low temperatures below Tg. If the glassy state of the thin film (monofilm) cannot be maintained at temperatures below Tg in this way, a problem arises in the fabrication of light-emitting devices where the organic EL layer formation process includes steps that require processing in air, as the organic EL layer may crystallize during the process, affecting the characteristics of the light-emitting device.

[0061] However, in one aspect of the present invention, the light-emitting device has electron transport layers (108-1, 108-2) having a stacked structure, and therefore its crystallization can be suppressed. Thus, in one aspect of the present invention, the light-emitting device can prevent the phenomenon of the film crystallizing below Tg due to the interaction between the stacked electron transport layers (108-1, 108-2). This can also be seen from the results shown in Examples 1 and 2.

[0062] Furthermore, in the above-mentioned light-emitting device, by using a laminated structure for the electron transport layers, the interaction between the laminated electron-transporting materials, which suppresses crystallization due to heat, is effective when the following conditions are met. Specifically, it is preferable to use a heteroaromatic compound for the first electron transport layer 108-1 in contact with the light-emitting layer, where the temperature difference between the crystallization temperature in the powder state (Tpc) and the crystallization temperature in the thin film state (Ttc) is 20°C or less, and to use a heteroaromatic compound for the second electron transport layer 108-2 formed in contact with the first electron transport layer 108-1, where the difference between the crystallization temperature in the powder state (Tpc) and the crystallization temperature in the thin film state (Ttc) is 100°C or less. With such a device configuration, even if a heating treatment is performed on the surface of the second electron transport layer 108-2, or a heating treatment is performed in the atmosphere, the crystallization of the materials used in the first electron transport layer 108-1 and the second electron transport layer 108-2 can be suppressed. Therefore, by adopting the structure of a light-emitting device according to one aspect of the present invention, even if the manufacturing process involves heat treatment during the formation of the organic EL layer or heat treatment in the atmosphere, it is possible to suppress the characteristics of the manufactured light-emitting device, thus offering the advantage of a high degree of process flexibility.

[0063] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0064] (Embodiment 2) In this embodiment, other configurations of the light-emitting device shown in Embodiment 1 will be explained using Figures 2(A) to 2(E).

[0065] ≪Basic Structure of Light-Emitting Devices≫ The basic structure of a light-emitting device will be described. Figure 2(A) shows a light-emitting device having an EL layer containing a light-emitting layer between a pair of electrodes. Specifically, it has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102.

[0066] Furthermore, Figure 2(B) shows a light-emitting device with a stacked structure (tandem structure) having multiple (two layers in Figure 2(B)) EL layers (103a, 103b) between a pair of electrodes, and a charge generation layer 106 between the EL layers. A light-emitting device with a tandem structure can realize a highly efficient light-emitting device without changing the amount of current.

[0067] The charge generation layer 106 has the function of injecting electrons into one EL layer (103a or 103b) and holes into the other EL layer (103b or 103a) when a potential difference is created between the first electrode 101 and the second electrode 102. Therefore, in Figure 2(B), when a voltage is applied to the first electrode 101 such that the potential is higher than that of the second electrode 102, electrons are injected from the charge generation layer 106 into EL layer 103a and holes are injected into EL layer 103b.

[0068] Furthermore, from the viewpoint of light extraction efficiency, it is preferable that the charge generation layer 106 is transparent to visible light (specifically, the transmittance of visible light to the charge generation layer 106 is 40% or more). In addition, the charge generation layer 106 can function even if its conductivity is lower than that of the first electrode 101 and the second electrode 102.

[0069] Figure 2(C) shows the laminated structure of the EL layer 103 of a light-emitting device according to one embodiment of the present invention. In this case, the first electrode 101 functions as an anode and the second electrode 102 functions as a 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 laminated on the first electrode 101. The light-emitting layer 113 may be a configuration in which multiple light-emitting layers of different emission colors are laminated. For example, a light-emitting layer containing a red light-emitting material, a light-emitting layer containing a green light-emitting material, and a light-emitting layer containing a blue light-emitting material may be laminated, or laminated via a layer having a carrier transport material. Alternatively, a combination of a light-emitting layer containing a yellow light-emitting material and a light-emitting layer containing a blue light-emitting material may be used. However, the laminated structure of the light-emitting layer 113 is not limited to the above. For example, the light-emitting layer 113 may be a structure in which multiple light-emitting layers of the same emission color are stacked. For example, a first light-emitting layer containing a blue light-emitting material and a second light-emitting layer containing a blue light-emitting material may be stacked, or a structure in which they are stacked via a layer having a carrier transport material. In the case of a structure in which multiple light-emitting layers of the same emission color are stacked, reliability can be increased compared to a single-layer structure. Also, even when there are multiple EL layers as in the tandem structure shown in Figure 2(B), each EL layer is stacked sequentially from the anode side as described above. Furthermore, if the first electrode 101 is the cathode and the second electrode 102 is the anode, the stacking order of the EL layer 103 is reversed. Specifically, on the first electrode 101, which is the cathode, 111 is an electron injection layer, 112 is an electron transport layer, 113 is a light-emitting layer, 114 is a hole transport layer, and 115 is a hole injection layer.

[0070] The light-emitting layers 113 contained in the EL layers (103, 103a, 103b) each contain a light-emitting material and a combination of multiple materials as appropriate, and can be configured to produce fluorescence emission or phosphorescence emission exhibiting a desired emission color. Alternatively, the light-emitting layers 113 may be arranged in a laminated structure with different emission colors. In this case, the light-emitting material and other materials used in each laminated light-emitting layer may be different materials. Alternatively, a configuration may be used in which different emission colors can be obtained from multiple EL layers (103a, 103b) as shown in Figure 2(B). In this case as well, the light-emitting material and other materials used in each light-emitting layer may be different materials.

[0071] Furthermore, in a light-emitting device according to one aspect of the present invention, for example, by using a reflective electrode as the first electrode 101 shown in Figure 2(C) and a semi-transparent / semi-reflective electrode as the second electrode 102, and by using a micro-cavity structure, the light emitted from the light-emitting layer 113 contained in the EL layer 103 can be resonated between the two electrodes, thereby strengthening the light emitted from the second electrode 102.

[0072] Furthermore, if the first electrode 101 of the light-emitting device is a reflective electrode consisting of a laminated structure of a reflective conductive material and a translucent conductive material (transparent conductive film), optical adjustment can be performed by controlling the film thickness of the transparent conductive film. Specifically, it is preferable to adjust the optical distance (product of film thickness and refractive index) between the first electrode 101 and the second electrode 102 to be mλ / 2 (where m is a natural number) or close to it, with respect to the wavelength λ of light obtained from the light-emitting layer 113.

[0073] 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 of the light-emitting layer 113 where the desired light is obtained (light-emitting region), and the optical distance from the second electrode 102 to the region of the light-emitting layer 113 where the desired light is obtained (light-emitting region), so that they are (2m'+1)λ / 4 (where m' is a natural number) or close to it. The light-emitting region referred to here is the region in the light-emitting layer 113 where holes and electrons recombine.

[0074] By performing such optical adjustments, the spectrum of specific monochromatic light obtained from the light-emitting layer 113 can be narrowed, resulting in emission with good color purity.

[0075] However, in the above case, the optical distance between the first electrode 101 and the second electrode 102 can be precisely defined as the total thickness from the reflective region of the first electrode 101 to the reflective region of the second electrode 102. However, since it is difficult to precisely determine the reflective regions of the first electrode 101 and the second electrode 102, the above effects can be sufficiently obtained by assuming that any position on the first electrode 101 and the second electrode 102 is the reflective region. Furthermore, the optical distance between the first electrode 101 and the light-emitting layer from which the desired light is obtained can be precisely defined as the optical distance between the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which the desired light is obtained. However, since it is difficult to precisely determine the reflective region of the first electrode 101 and the light-emitting region of the light-emitting layer from which the desired light is obtained, the above effects can be sufficiently obtained by assuming that any position on the first electrode 101 is the reflective region and any position on the light-emitting layer from which the desired light is obtained is the light-emitting region.

[0076] The light-emitting device shown in Figure 2(D) is a light-emitting device having a tandem structure and a microcavity structure, which allows for the extraction of light of different wavelengths (monochromatic light) from each EL layer (103a, 103b). Therefore, color separation (e.g., RGB) to obtain different emission colors is unnecessary. Consequently, high resolution can be easily achieved. It can also be combined with a colored layer (color filter). Furthermore, it is possible to strengthen the emission intensity in the front direction at a specific wavelength, thereby reducing power consumption.

[0077] The light-emitting device shown in Figure 2(E) is an example of a tandem-structured light-emitting device shown in Figure 2(B). As shown in the figure, it has a structure in which three EL layers (103a, 103b, 103c) are stacked with charge generation layers (106a, 106b) in between. Each of the three EL layers (103a, 103b, 103c) has a light-emitting layer (113a, 113b, 113c), and the light-emitting colors of each light-emitting layer can be freely combined. For example, light-emitting layer 113a can be blue, light-emitting layer 113b can be red, green, or yellow, and light-emitting layer 113c can be blue. Alternatively, light-emitting layer 113a can be red, light-emitting layer 113b can be blue, green, or yellow, and light-emitting layer 113c can be red.

[0078] In the light-emitting device according to one aspect of the present invention described above, at least one of the first electrode 101 and the second electrode 102 is a light-transmitting electrode (such as a transparent electrode or a semi-transparent / semi-reflective electrode). If the light-transmitting electrode is a transparent electrode, the transmittance of visible light of the transparent electrode shall be 40% or more. If it is a semi-transparent / semi-reflective electrode, the reflectance of visible light of the semi-transparent / semi-reflective electrode shall be 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, the resistivity of these electrodes shall be 1 × 10⁻⁶. -2 It is preferable to keep it below Ωcm.

[0079] Furthermore, in the light-emitting device according to one aspect of the present invention described above, if 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. In addition, the resistivity of this electrode is 1 × 10⁻⁶. -2 It is preferable to keep it below Ωcm.

[0080] ≪Specific structure of a light-emitting device≫ Next, a specific structure of a light-emitting device according to one aspect of the present invention will be described. Here, we will use Figure 2(D), which has a tandem structure, for explanation. The same applies to the EL layer configuration for the single-structure light-emitting devices shown in Figures 2(A) and 2(C). Furthermore, if the light-emitting device shown in Figure 2(D) has a microcavity structure, the first electrode 101 is formed as a reflective electrode, and the second electrode 102 is formed as a semi-transparent / semi-reflective electrode. Thus, one or more desired electrode materials can be used and formed as a single layer or in a stacked manner. The second electrode 102 is formed after the EL layer 103b is formed, by selecting an appropriate material.

[0081] <First electrode and second electrode> As materials for forming the first electrode 101 and the second electrode 102, any combination of the following materials can be used as long as the functions of both electrodes described above are met. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used as appropriate. Specifically, these include In-Sn oxide (also called ITO), In-Si-Sn oxide (also called ITSO), In-Zn oxide, and In-W-Zn oxide. In addition, metals such as aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), and alloys containing these in appropriate combinations can also be used. In addition, elements belonging to Group 1 or Group 2 of the periodic table not exemplified above (for example, lithium (Li), cesium (Cs), calcium (Ca), strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these in appropriate combinations, as well as graphene and other materials can be used.

[0082] In the light-emitting device shown in Figure 2(D), 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 laminated on the first electrode 101 by vacuum deposition. 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 similarly sequentially laminated on the charge generation layer 106.

[0083] <Hole injection layer> The hole injection layers (111, 111a, 111b) are layers that inject holes from the first electrode 101, which is the anode, and the charge generation layers (106, 106a, 106b) into the EL layers (103, 103a, 103b), and are layers that contain organic acceptor material and material with high hole injection potential.

[0084] Organic acceptor materials are materials that can generate holes in an organic compound by separating its charge from other organic compounds whose LUMO level and HOMO level are close in value. Therefore, compounds having electron-withdrawing groups (halogen groups or cyano groups), such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives, can be used as organic acceptor materials. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexazatriphenylene (abbreviated as HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviated as F6-TCNNQ), 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyrene-2-ylidene)malononitrile, etc. can be used. Furthermore, among organic acceptor materials, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are particularly suitable because they have high acceptability and stable film properties with respect to heat. In addition, radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) [3] are also preferred because they have very high electron-accepting properties. Specifically, α,α',α''-1,2,3-cyclopropanetriylidenates[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenates[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenates[2,3,4,5,6-pentafluorobenzeneacetonitrile] can be used.

[0085] Furthermore, as materials with high hole injection potential, oxides of metals belonging to groups 4 through 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 preferred because it is stable in the atmosphere, has low hygroscopicity, and is easy to handle. In addition, phthalocyanine compounds such as phthalocyanine (abbreviated as H2Pc) or copper phthalocyanine (abbreviated as CuPc) can be used.

[0086] In addition to the above materials, the low molecular weight compounds 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5- Aromatic amine compounds such as tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0087] Furthermore, polymer compounds (oligomers, dendrimers, polymers, etc.) 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), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD) can be used. Alternatively, polymer compounds to which acids such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviated as PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS) can be added can also be used.

[0088] Furthermore, as a material with high hole injection capabilities, a mixed material containing a hole transport material and the aforementioned organic acceptor material (electron-accepting material) can also be used. In this case, electrons are extracted from the hole transport material by the organic acceptor material, generating holes in the hole injection layer 111, and these holes are injected into the light-emitting layer 113 via the hole transport layer 112. The hole injection layer 111 may be formed as a single layer of a mixed material containing a hole transport material and an organic acceptor material (electron-accepting material), or it may be formed by laminating the hole transport material and the organic acceptor material (electron-accepting material) in separate layers.

[0089] Furthermore, for hole-transporting materials, the hole mobility at which the square root of the electric field strength [V / cm] is 600 is 1 × 10⁻⁶. -6 cm 2 A material having a hole mobility of / Vs or higher is preferred. However, any material that has higher hole transport than electron transport can be used.

[0090] Furthermore, preferred hole-transporting materials include compounds having a π-electron-rich heteroaromatic ring (e.g., carbazole derivatives, furan derivatives, or thiophene derivatives) and aromatic amines (organic compounds having an aromatic amine skeleton), which are materials with high hole-transporting properties.

[0091] Examples of the above-mentioned carbazole derivatives (organic compounds having a carbazole ring) include bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives) and aromatic amines having a carbazolyl group.

[0092] Furthermore, specific examples of the above-mentioned bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives) include 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), 9,9'-bis(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 BismBPCz), 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).

[0093] Furthermore, examples of aromatic amines having the above-mentioned carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazole-3-amine (abbreviated as PCBiF), and N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3- [9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazole-3-yl) Diphenylamine (abbreviation: PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazole-3-yl)amine (abbreviation: PCA1BP), N,N'-bis(9-phenylcarbazole-3-yl)-N,N'-diphenylbenzene-1,3-diamine (abbreviation: PCA2B), N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazole-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9 ,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-Bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3,[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-Bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA2), 3,6-Bis[N-(4-diphenylaminophenyl)-N-(1 Examples include -naphthyl)amino]-9-phenylcarbazole (abbreviation: PCzTPN2), 2-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (abbreviation: PCASF), N-[4-(9H-carbazole-9-yl)phenyl]-N-(4-phenyl)phenylaniline (abbreviation: YGA1BP), N,N'-bis[4-(carbazole-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (abbreviation: YGA2F), and 4,4',4''-tris(carbazole-9-yl)triphenylamine (abbreviation: TCTA).

[0094] In addition to the above, other examples of carbazole derivatives include 3-[4-(9-phenanthryl)-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'-di(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-anthracenyl)phenyl]-9H-carbazole (abbreviated as CzPA).

[0095] Furthermore, specific examples of the above-mentioned furan derivatives (organic compounds having a furan ring) include 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II).

[0096] Furthermore, specific examples of the above-mentioned thiophene derivatives (organic compounds having a thiophene ring) include 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV).

[0097] Furthermore, the above aromatic amines specifically 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'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviated as BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as BPAFLP), and 4-phenyl-3 '-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9 ,9'-bifluorene (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]spiro-9,9'-bifluorene (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-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenyl Min (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: BBAαNβNB-03), 4,4'-diphenyl-4''-(7-phenyl)na Phthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4' '-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazole-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazole-9-yl)phenyl]tris(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'-spirobio[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis([1,1'-bi Phenyl]-4-yl)-9,9'-spirobio[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis([1,1'-biphenyl]-4-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluorene-2-yl)-9,9'-spirobio[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), N,N-bis(9,9-dimethyl-9H-fluoren-2- Examples include N,N-bis(9,9-dimethyl-9H-fluoren-4-amine), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-2-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-9H-fluoren-1-amine, etc.

[0098] In addition, polymer compounds (oligomers, dendrimers, polymers, etc.) 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), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD) can be used as hole transport materials. Alternatively, polymer compounds to which acids such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviated as PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS) can be added can also be used.

[0099] However, the hole transport material is not limited to the above, and various known materials may be used as a hole transport material by combining one or more of them.

[0100] The hole injection layers (111, 111a, 111b) can be formed using various known film deposition methods, for example, by vacuum deposition.

[0101] <Hole transport layer> The hole transport layers (112, 112a, 112b) are layers that transport holes injected from the first electrode 101 by the hole injection layers (111, 111a, 111b) to the light-emitting layers (113, 113a, 113b). The hole transport layers (112, 112a, 112b) are layers containing a hole-transporting material. Therefore, the hole transport layers (112, 112a, 112b) can use the same hole-transporting material that can be used in the hole injection layers (111, 111a, 111b).

[0102] In one embodiment of the present invention, the same organic compound used in the hole transport layer (112, 112a, 112b) can be used in the light-emitting layer (113, 113a, 113b). Using the same organic compound in both the hole transport layer (112, 112a, 112b) and the light-emitting layer (113, 113a, 113b) is preferable because it allows for more efficient transport of holes from the hole transport layer (112, 112a, 112b) to the light-emitting layer (113, 113a, 113b).

[0103] <Luminous layer> The light-emitting layers (113, 113a, 113b) are layers containing a light-emitting material. The light-emitting material that can be used in the light-emitting layers (113, 113a, 113b) can be any material that exhibits a light-emitting color such as blue, purple, blue-violet, green, yellow-green, yellow, orange, or red. Furthermore, if there are multiple light-emitting layers, a configuration exhibiting different light-emitting colors can be achieved by using different light-emitting materials in each layer (for example, white light emission obtained by combining complementary light-emitting colors). Additionally, a laminated structure in which each light-emitting layer contains a different light-emitting material is also possible.

[0104] Furthermore, the light-emitting layers (113, 113a, 113b) may contain one or more types of organic compounds (host materials, etc.) in addition to the light-emitting substance (guest material).

[0105] Furthermore, when multiple host materials are used in the light-emitting layers (113, 113a, 113b), it is preferable to use a material with a larger energy gap than the energy gaps of the existing guest material and the first host material as the newly added second host material. It is also 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 triplet 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. With this configuration, an excitation complex can be formed using two types of host materials. In order to efficiently form the excitation complex, it is particularly preferable to combine a compound that readily accepts holes (hole transport material) with a compound that readily accepts electrons (electron transport material). This configuration also enables the simultaneous achievement of high efficiency, low voltage, and long lifespan.

[0106] The organic compounds used as the host material (including the first and second host materials) can be hole-transporting materials that can be used in the aforementioned hole-transporting layers (112, 112a, 112b), or electron-transporting materials that can be used in the electron-transporting layers (114, 114a, 114b) described later, as long as they satisfy the conditions for being a host material used in the light-emitting layer. An excited complex composed of multiple types of organic compounds (the first and second host materials) may also be used. An excited complex (also called an exciplex) that forms an excited state with multiple types of organic compounds has an extremely small difference between the S1 and T1 levels and functions as a TADF material that can convert triplet excitation energy into singlet excitation energy. Furthermore, as a combination of multiple types of organic compounds that form an excited complex, for example, it is preferable that one has a π-electron-deficient heteroaromatic ring and the other has a π-electron-rich heteroaromatic ring. Furthermore, as a combination for forming the excitation complex, one of the components may be a phosphorescent material such as an iridium, rhodium, or platinum-based organometallic complex, or a metal complex.

[0107] There are no particular limitations on the luminescent material that can be used in the luminescent layers (113, 113a, 113b). A luminescent material that converts singlet excitation energy into visible light emission, or a luminescent material that converts triplet excitation energy into visible light emission, can be used.

[0108] <<Luminescent material that converts singlet excitation energy into light emission>> Examples of luminescent materials that can be used in the light-emitting layers (113, 113a, 113b) to convert singlet excitation energy into light include the following fluorescent materials (fluorescent materials). For example, pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, and naphthalene derivatives are examples. Pyrene derivatives are particularly preferred because they have a high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophen-2-yl)-N, Examples include N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), and N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03).

[0109] Also, 5,6-bis[4-(10-phenyl-9-antryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-antryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazole-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazole (9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazole-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'- (9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-antryl)phenyl]-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl) Nilen)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviated as DPABPA), N,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), etc. can be used.

[0110] Also, N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazole-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPABPhA), 9,10-bis(1,1'-biphenyl -2-yl)-N-[4-(9H-carbazole-9-yl)phenyl]-N-phenylanthracene-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracene-9-amine (abbreviation: DPhAPhA), coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubren, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6-methyl-4H-pyran-4-yl DCM1)propanedinitrile, 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-diamine (p -mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB), 2-(2,6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-Bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), 1,6BnfAP Examples include rn-03, 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), and 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02). In particular, pyrenediamine compounds such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03 can be used.

[0111] <<Luminescent material that converts triplet excitation energy into light emission>> Next, examples of light-emitting materials that can be used in the light-emitting layer 113 to convert triplet excitation energy into light include phosphorescent materials (phosphorescent materials) or thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

[0112] A phosphorescent material is a compound that exhibits phosphorescence and does not fluoresce at any temperature range above low temperatures (e.g., 77K) and below room temperature (i.e., between 77K and 313K). The phosphorescent material preferably contains a metal element with strong spin-orbit interaction, and examples include organometallic complexes, metal complexes (platinum complexes), and rare earth metal complexes. Specifically, transition metal elements are preferred, and particularly platinum group elements (ruthenium (Ru), rhodium (Rh), palladium (Pd), osmium (Os), iridium (Ir), or platinum (Pt)) are preferred. The presence of iridium is especially preferable because it increases the transition probability involved in the direct transition between the singlet ground state and the triplet excited state.

[0113] ≪Phosphorescent materials (450nm to 570nm: blue or green)≫ Examples of phosphorescent materials that exhibit blue or green light and have a peak wavelength of emission spectrum between 450 nm and 570 nm include the following:

[0114] For example, Tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]), Tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]), Tris[4-(3-biphenyl [Ir(iPrptz-3b)3], Tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPr5btz)3]), organometallic complexes having a 4H-triazole ring such as Tris[3-methyl-1-( Organometallic complexes having a 1H-triazole ring, such as 2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), and fac-tris[1-(2,6-diisopropyl Organometallic complexes having an imidazole ring, such as phenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridineto]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), and bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) tetrakis(1-pyrazolyl) borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: Firpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinate-N,C 2’ Iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinate-N,C 2’Examples include organometallic complexes that use phenylpyridine derivatives having electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as Fir(acac)).

[0115] ≪Phosphorescent materials (495nm to 590nm: green or yellow)≫ Examples of phosphorescent materials that exhibit a green or yellow color and have a peak wavelength of emission spectrum between 495 nm and 590 nm include the following:

[0116] For example, organometallic iridium complexes having a pyrimidine ring such as tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]); organometallic iridium complexes having a pyrazine ring such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]); tris(2-phenylpyridinato-N,C 2’ )iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinate)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinate)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinate-N,C) 2’ Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C) 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC] Iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl [-κN)phenyl-κC], [2-d3-methyl-8-(2-pyridinyl-κN)benzofl[2,3-b]pyridinyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), [2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzofl [2,3-b]pyridinyl-7-yl-κC]bis[5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC]iridium(III) (abbreviation: Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridinyl-κN)benzofloflo[2,3-b]pyridinyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC Organometallic iridium complexes having a pyridine ring, such as iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)), [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mdppy)), and bis(2,4-diphenyl-1,3-oxazolato-N,C 2’Iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinate-N,C 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolat-N,C) 2’ Examples include organometallic complexes such as iridium(III) acetylacetonate (abbreviated as [Ir(bt)2(acac)]), as well as rare earth metal complexes such as tris(acetylacetonate)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]).

[0117] ≪Phosphorescent materials (570nm to 750nm: yellow or red)≫ Examples of phosphorescent materials that exhibit a yellow or red color and have a peak wavelength of emission spectrum between 570 nm and 750 nm include the following:

[0118] For example, (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), (dipivaloylmethanato)bis[4,6-di(naphthalene-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), and other pyramidal compounds. Organometallic complexes having a limidine ring: (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κ 2O,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-pyradinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ 2 O,O') Iridium(III) (abbreviation: [Ir(dmdppr-dmCP)2(dpm)]), bis[2-(5-(2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN)-4,6-dimethylphenyl-κC](2,2',6,6'-tetramethyl-3,5-heptanedionato-κ 2 O,O') Iridium(III) (abbreviation: [Ir(dmdppr-dmp)2(dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C 2’ Iridium(III) (abbreviation: [Ir(mpq)2(acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C) 2’ Organometallic complexes having a pyrazine ring, such as iridium(III) (abbreviation: [Ir(dpq)2(acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and tris(1-phenylisoquinolinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C) 2’ Iridium(III) acetylacetonate (abbreviation: [Ir(piq)2(acac)]), and bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ 2Examples include organometallic complexes having a pyridine ring, such as O,O')iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviation: [PtOEP]), tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), and rare earth metal complexes such as tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]).

[0119] ≪TADF material≫ Furthermore, the following materials can be used as TADF materials. A TADF material is a material in which the difference between the S1 level and the T1 level is small (preferably 0.2 eV or less), the triplet excited state can be upconverted to the singlet excited state with a small amount of thermal energy (reverse intersystem crossing), and the emission (fluorescence) from the singlet excited state is efficiently exhibited. Furthermore, conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excited energy level and the singlet excited energy level being 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. In addition, delayed fluorescence in TADF materials refers to emission that has a spectrum similar to normal fluorescence but with a remarkably long lifetime. Its lifetime is 1 × 10⁻⁶ -6 For more than a second, preferably 1 × 10⁻⁶ seconds. -3 It is more than a second.

[0120] Examples of TADF materials include fullerenes and their derivatives, acridine derivatives such as proflavin, and eosin. Also, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd) are also included. Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complexes (abbreviated as SnF2(Proto IX)), mesoporphyrin-tin fluoride complexes (abbreviated as SnF2(Meso IX)), hematoporphyrin-tin fluoride complexes (abbreviated as SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complexes (abbreviated as SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complexes (abbreviated as SnF2(OEP)), etioporphyrin-tin fluoride complexes (abbreviated as SnF2(Etio I)), and octaethylporphyrin-platinum chloride complexes (abbreviated as PtCl2OEP).

[0121] [ka]

[0122] Other examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviated as PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviated as PCCzPTzn), and 2-[4-(10H-phenoxy [Sadin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviation: ACRXTN), bis[4-(9, 9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), 4-(9'-phenyl-3,3'-bi-9H-carbazole-9-yl)benzoflo[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm), 4-[4-(9'-phenyl-3,3'- Hetero-aromatic compounds having π-electron-rich hetero-aromatic compounds and π-electron-deficient hetero-aromatic compounds such as bi-9H-carbazole-9-yl)phenyl]benzofl[3,2-d]pyrimidine (abbreviation: 4PCCzPBfpm) and 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02) may also be used.

[0123] Furthermore, a material in which a π-electron-rich heteroaromatic compound and a π-electron-deficient heteroaromatic compound are directly bonded is particularly preferable because both the donor properties of the π-electron-rich heteroaromatic compound and the acceptor properties of the π-electron-deficient heteroaromatic compound become stronger, and the energy difference between the singlet excited state and the triplet excited state becomes smaller. In addition, a TADF material (TADF100) in which the singlet excited state and the triplet excited state are in thermal equilibrium may be used as the TADF material. Since such a TADF material has a shorter luminescence lifetime (excitation lifetime), it is possible to suppress the decrease in efficiency in the high-brightness region of the light-emitting element.

[0124] [ka]

[0125] In addition to the above, other materials that have the function of converting triplet excitation energy into light emission include nanostructures of transition metal compounds having a perovskite structure. Nanostructures of metal halogen perovskites are particularly preferred. Nanoparticles and nanorods are preferred as such nanostructures.

[0126] In the light-emitting layers (113, 113a, 113b, 113c), the organic compounds (host materials, etc.) used in combination with the light-emitting material (guest material) described above may be one or more materials having an energy gap larger than the energy gap of the light-emitting material (guest material).

[0127] ≪Host materials for fluorescence emission≫ When the light-emitting material used in the light-emitting layer (113, 113a, 113b, 113c) is a fluorescent light-emitting material, it is preferable to use an organic compound (host material) that has a large singlet excited state energy level and a small triplet excited state energy level, or an organic compound with a high fluorescence quantum yield. Therefore, any organic compound that satisfies these conditions can be used, such as the hole transport material (described above) and electron transport material (described below) shown in this embodiment.

[0128] Although some of these overlap with the specific examples mentioned above, from the perspective of preferred combinations with luminescent substances (fluorescent substances), examples of organic compounds (host materials) include condensed polycyclic aromatic compounds such as anthracene derivatives, tetracene derivatives, phenanthrene derivatives, pyrene derivatives, chrysene derivatives, and dibenzo[g,p]chrysene derivatives.

[0129] Specific examples of organic compounds (host materials) that are preferable to use in combination with fluorescent luminescent substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviated as DPCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), and 9,10-diphenylanthracene (abbreviated as :DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazole-3-amine (abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-di Phenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)-biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracene-9-yl)dibenzofuran, 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAn Examples include 1-[4-(10-[1,1'-biphenyl]-4-yl-9-anthracenyl)phenyl]-2-ethyl-1H-benzimidazole (abbreviated as EtBImPBPhA), 9,9'-biantryl (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-tri(1-pyrenyl)benzene (abbreviated as TPB3), 5,12-diphenyltetracene, and 5,12-bis(biphenyl-2-yl)tetracene.

[0130] ≪Host materials for phosphorescence≫ Furthermore, when the luminescent material used in the luminescent layers (113, 113a, 113b, 113c) is a phosphorescent material, it is sufficient to select an organic compound (host material) to combine with it that has a triplet excitation energy greater than the triplet excitation energy of the luminescent material (the energy difference between the ground state and the triplet excited state). When using multiple organic compounds (for example, a first host material and a second host material (or assist material), etc.) in combination with the luminescent material to form an excited complex, it is preferable to mix these multiple organic compounds with the phosphorescent material.

[0131] This configuration allows for efficient emission using ExTET (Exciplex-Triplet Energy Transfer), which is energy transfer from the excited complex to the luminescent material. The combination of organic compounds should ideally be one that readily forms an excited complex, and a combination of a compound that readily accepts holes (hole transport material) and a compound that readily accepts electrons (electron transport material) is particularly preferable.

[0132] In addition, although some of these overlap with the specific examples mentioned above, from the perspective of preferred combinations with luminescent substances (phosphorescent substances), suitable organic compounds (host materials, assist materials) include aromatic amines (organic compounds having an aromatic amine skeleton), carbazole derivatives (organic compounds having a carbazole ring), dibenzothiophene derivatives (organic compounds having a dibenzothiophene ring), dibenzofuran derivatives (organic compounds having a dibenzofuran ring), oxadiazole derivatives (organic compounds having an oxadiazole ring), triazole derivatives (organic compounds having a triazole ring), and benzimidazole derivatives (benzo- Examples include organic compounds having a midazole ring, quinoxaline derivatives (organic compounds having a quinoxaline ring), dibenzoquinoxaline derivatives (organic compounds having a dibenzoquinoxaline ring), pyrimidine derivatives (organic compounds having a pyrimidine ring), triazine derivatives (organic compounds having a triazine ring), pyridine derivatives (organic compounds having a pyridine ring), bipyridine derivatives (organic compounds having a bipyridine ring), phenanthroline derivatives (organic compounds having a phenanthroline ring), phlodiazine derivatives (organic compounds having a phlodiazine ring), zinc and aluminum-based metal complexes, etc.

[0133] Furthermore, among the above-mentioned organic compounds, specific examples of aromatic amines and carbazole derivatives, which are organic compounds with high hole transport properties, are the same as the specific examples of hole transport materials described above, and all of these are preferred as host materials.

[0134] Furthermore, among the above organic compounds, specific examples of dibenzothiophene derivatives and dibenzofuran derivatives, which are organic compounds with high hole transport properties, include 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), DBT3P-II, and 2,8-diphenyl Examples include nyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviated as DBTFLP-III), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and 4-[3-(triphenylene-2-yl)phenyl]dibenzothiophene (abbreviated as mDBTPTp-II), all of which are preferred as host materials.

[0135] Other preferred host materials include metal complexes having oxazole-based or thiazole ligands such as bis[2-(2-benzoxazolyl)phenolate]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenolate]zinc(II) (abbreviated as ZnBTZ).

[0136] Furthermore, among the above organic compounds, specific examples of organic compounds with high electron transport properties, such as oxadiazole derivatives, triazole derivatives, benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, and phenanthroline derivatives, include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviation: OXD-7), and 9-[4-(5-phenyl -1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 4,4'-bis(5-methylbenzoxazole- Organic compounds containing heteroaromatic rings with polyazole rings, such as 2-yl)stilbene (abbreviation: BzOS), and pyridine rings such as vasophenanthroline (abbreviation: Bphen), vasocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2-(1,3-phenylene)bis[9-phenyl-1,10-phenanthroline] (abbreviation: mPPhen2P), and 2,2'-[biphenyl]-4,4'-diylbis[1,10-phenanthroline] (abbreviation: Phen2BP). Organic compounds containing a heteroaromatic ring having , 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazole-9-yl)phenyl]dibenzo[f,Examples include [h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), and all of these are preferred as host materials.

[0137] Furthermore, among the above organic compounds, specific examples of organic compounds with high electron transport capabilities include pyridine derivatives, diazine derivatives (including pyrimidine derivatives, pyrazine derivatives, and pyridazine derivatives), triazine derivatives, and phlodiazine derivatives, such as 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and 4,6-bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine. (Abbreviation: 4,6mCzP2Pm), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (Abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazol (Abbreviation: mPCCzPTzn-02), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (Abbreviation: 35DCzPPy), 1,3,5- Li[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 9,9'-[pyrimidine-4,6-diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofl[3,2-d]pi Limidine (abbreviation: 8BP-4mDBtPBfpm), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-[(3'-dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]flo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylene-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobio(9H-fluoren)-2-yl]-1 ,3,5-triazine (abbreviation: BP-SFTzn), 2,6-bis(4-naphthalene-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzothiophenyl]-2-phenyl-9H-carbazole (abbreviation: PC Examples include organic compounds containing heteroaromatic rings having a diazine ring, such as DBfTzn, 2-[1,1'-biphenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1''-terphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviated as mBP-TPDBfTzn), 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2PPm), and 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm), all of which are preferred as host materials.

[0138] Furthermore, among the above organic compounds, specific examples of metal complexes that are organic compounds with high electron transport properties include zinc or aluminum-based metal complexes such as tris(8-quinolinolato)aluminum(III) (abbreviated as Alq), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviated as Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviated as BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), bis(8-quinolinolato)zinc(II) (abbreviated as Znq), and metal complexes having a quinoline ring or a benzoquinoline ring, all of which are preferred as host materials.

[0139] Other polymer compounds such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) are also preferred as host materials.

[0140] Furthermore, there are bipolar organic compounds that are highly hole-transporting and highly electron-transporting, such as 9-phenyl-9'-(4-phenyl-2-quinazolinyl)-3,3'-bi-9H-carbazole (abbreviation: PCCzQz), 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), and 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1 Organic compounds having a diazine ring, such as -b]carbazole (abbreviation: mINc(II)PTzn), 11-(4-[1,1'-biphenyl]-4-yl-6-phenyl-1,3,5-triazine-2-yl)-11,12-dihydro-12-phenyl-indoro[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), and 7-[4-(9-phenyl-9H-carbazole-2-yl)quinazoline-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), can also be used as host materials.

[0141] <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) by the electron injection layers (115, 115a, 115b), described later, to the light-emitting layers (113, 113a, 113b). In one embodiment of the present invention, the light-emitting device can improve heat resistance by having a laminated structure for the electron transport layers. Furthermore, the electron-transporting material used in the electron transport layers (114, 114a, 114b) has an electron mobility of 1 × 10⁻¹⁰ at a square root of 600 electric field strength [V / cm]. -6 cm 2 A material having an electron mobility of / Vs or higher is preferred. However, any material with higher electron transport capabilities than hole transport can be used. Furthermore, the electron transport layer (114, 114a, 114b) can function as a single layer, but it may also be a laminated structure of two or more layers. Since the above mixed material has heat resistance, performing the photolithography process on an electron transport layer using this material can suppress the influence of the thermal process on the device characteristics.

[0142] ≪Electron transport material≫ As electron-transporting materials that can be used in the electron transport layers (114, 114a, 114b), organic compounds with high electron transport properties can be used, for example, heteroaromatic compounds can be used. A heteroaromatic compound is a cyclic compound that contains at least two different elements in its ring. The ring structure can include 3-membered rings, 4-membered rings, 5-membered rings, 6-membered rings, etc., but 5-membered rings or 6-membered rings are particularly preferred, and heteroaromatic compounds that contain one or more of the elements carbon, nitrogen, oxygen, or sulfur are preferred. Nitrogen-containing heteroaromatic compounds (nitrogen-containing heteroaromatic compounds) are particularly preferred, and it is preferable to use materials with high electron transport properties (electron-transporting materials) such as nitrogen-containing heteroaromatic compounds or π-electron-deficient heteroaromatic compounds containing them.

[0143] Heteroaromatic compounds are organic compounds that have at least one heteroaromatic ring.

[0144] Furthermore, a heteroaromatic ring contains one of the following: a pyridine ring, a diazine ring, a triazine ring, a polyazole ring, an oxazole ring, or a thiazole ring. Heteroaromatic rings containing a diazine ring include heteroaromatic rings containing a pyrimidine ring, a pyrazine ring, or a pyridazine ring. Heteroaromatic rings containing a polyazole ring include heteroaromatic rings containing an imidazole ring, a triazole ring, or an oxadiazole ring.

[0145] Furthermore, heteroaromatic rings include fused heteroaromatic rings having a fused ring structure. Examples of fused heteroaromatic rings include quinoline rings, benzoquinoline rings, quinoxaline rings, dibenzoquinoxaline rings, quinazoline rings, benzoquinazoline rings, dibenzoquinazoline rings, phenanthroline rings, phlodiazine rings, and benzimidazole rings.

[0146] Examples of heteroaromatic compounds include, among heteroaromatic compounds containing one or more of nitrogen, oxygen, or sulfur in addition to carbon, heteroaromatic compounds having a five-membered ring structure such as heteroaromatic compounds having an imidazole ring, heteroaromatic compounds having a triazole ring, heteroaromatic compounds having an oxazole ring, heteroaromatic compounds having an oxadiazole ring, heteroaromatic compounds having a thiazole ring, and heteroaromatic compounds having a benzimidazole ring.

[0147] Furthermore, among heteroaromatic compounds that contain one or more elements other than carbon, such as nitrogen, oxygen, or sulfur, examples of heteroaromatic compounds having a six-membered ring structure include heteroaromatic compounds having heteroaromatic rings such as pyridine rings, diazine rings (including pyrimidine rings, pyrazine rings, pyridazine rings, etc.), triazine rings, and polyazole rings. Note that while heteroaromatic compounds with a structure in which pyridine rings are linked, examples include heteroaromatic compounds having a bipyridine structure and heteroaromatic compounds having a terpyridine structure.

[0148] Furthermore, examples of heteroaromatic compounds having a fused ring structure that partially includes the above-mentioned six-membered ring structure include heteroaromatic compounds having fused heteroaromatic rings such as quinoline rings, benzoquinoline rings, quinoxaline rings, dibenzoquinoxaline rings, phenanthroline rings, phlodiazine rings (including structures in which an aromatic ring is fused to the furan ring of a phlodiazine ring), and benzimidazole rings.

[0149] Specific examples of heteroaromatic compounds having the above-mentioned five-membered ring structure (polyazole ring (including imidazole ring, triazole ring, oxadiazole ring), oxazole ring, thiazole ring, benzimidazole ring, etc.) include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), and 3-(4-biphenylyl)-4-phenyl Examples include phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviated as p-EtTAZ), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazole-2-yl)stilbene (abbreviated as BzOS).

[0150] Specific examples of heteroaromatic compounds having the above-mentioned six-membered ring structure (including heteroaromatic rings having pyridine rings, diazine rings, triazine rings, etc.) include heteroaromatic compounds containing a pyridine ring, such as 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and 2-{4-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}-4,6-diphenyl-1,3,5- Triazine (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazine-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylene-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine ( (Abbreviation: mTpBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluorene)-2-yl]-1,3,5-triazine (Abbreviation: BP-SFTzn), 2,6-bis(4-naphthalene-1-ylphenyl)-4-[4-(3-pyridyl)phenyl]pyrimidine (Abbreviation: 2,4NP-6PyPPm), 9-[4-(4,6-diphenyl-1,3,5-triazine-2-yl)-2-dibenzothiophenyl]-2-phenyl-9H-carbazole (Abbreviation: PCDBfTzn), 2-[1,1'-bi Heteroaromatic compounds containing heteroaromatic rings having a triazine ring, such as phenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1''-terphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviation: mBP-TPDBfTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), mFBPTzn, 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-Bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-Bis[3-(9H-carbazole-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 4,6mCzBP2Pm, 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6mBP-4Cz2 PPm), 4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalene-2-yl)-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8BP-4mDBtPBfpm, 9mDBtBP Nfpr, 9pmDBtBPNfpr, 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzoflo[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl- Examples include heteroaromatic compounds containing a heteroaromatic ring having a diazine (pyrimidine) ring, such as 3-yl)naphtho[1',2':4,5]flo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm) and 8-[(2,2'-binaphthalene)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm). Note that the above aromatic compounds containing heteroaromatic rings include heteroaromatic compounds having condensed heteroaromatic rings.

[0151] Other examples include 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 6,6'(P-Bqn)2BPy), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviation: 2,6(NP-PPm)2Py), and 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazole-9-yl)phenyl]-2-phenylpyrimidine (abbreviation: 6 Examples include heteroaromatic compounds containing heteroaromatic rings having a diazine (pyrimidine) ring, such as mBP-4Cz2PPm, and heteroaromatic compounds containing heteroaromatic rings having a triazine ring, such as 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2,4,6-tris(2-pyridyl)-1,3,5-triazine (abbreviation: 2Py3Tz), and 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenantrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn).

[0152] Specific examples of heteroaromatic compounds having a fused ring structure that partially includes a 6-membered ring structure (heteroaromatic compounds having a fused ring structure) include bathophenanthroline (abbreviation: Bphen), vasocuproin (abbreviation: BCP), 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), and 2,2'-(1,3-phenylene)bis[9-phen [Phenyl-1,10-phenanthroline] (abbreviation: mPPhen2P), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation: 2,6(P-Bqn)2Py), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline [biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPD Examples include heteroaromatic compounds having a quinoxaline ring, such as Bq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2mpPCBPDBq, etc.

[0153] In addition to the heteroaromatic compounds shown above, the following metal complexes can be used in the electron transport layers (114, 114a, 114b). Examples include metal complexes having a quinoline ring or benzoquinoline ring, such as tris(8-quinolinolato)aluminum(III) (abbreviated as Alq3), Almq3, 8-quinolinolatritium(I) (abbreviated as Liq), BeBq2, bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviated as BAlq), and bis(8-quinolinolato)zinc(II) (abbreviated as Znq); and metal complexes having an oxazole ring or thiazole ring, such as bis[2-(2-benzoxazollyl)phenolato]zinc(II) (abbreviated as ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviated as ZnBTZ).

[0154] Furthermore, polymer compounds such as poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy) can also be used as electron transport materials.

[0155] Furthermore, the electron transport layers (114, 114a, 114b) may be not only single layers, but also have a structure in which two or more layers made of the above material are stacked.

[0156] <Electron injection layer> The electron injection layers (115, 115a, 115b) are layers containing a material with high electron injection capabilities. Furthermore, the electron injection layers (115, 115a, 115b) are layers for increasing the electron injection efficiency from the second electrode 102, and it is preferable to use a material in which the difference between the work function value of the material used for the second electrode 102 and the LUMO level value of the material used for the electron injection layers (115, 115a, 115b) is small (0.5 eV or less). Therefore, the electron injection layers 115, 115a, and 115b) contain lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-(quinolinolato)lithium (abbreviated as Liq), 2-(2-pyridyl)phenolate (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatritium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolate (abbreviated as LiPPP), and lithium oxide (LiO2). x Alkali metals such as cesium carbonate, alkaline earth metals, or compounds thereof can be used. Rare earth metals such as ytterbium (Yb) or rare earth metal compounds such as erbium fluoride (ErF3) can also be used. The electron injection layers (115, 115a, 115b) may be formed by mixing multiple types of the above materials, or by stacking multiple types of the above materials. Electrides may also be used in the electron injection layers (115, 115a, 115b). Examples of electrides include substances obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum. The materials that constitute the electron transport layers (114, 114a, 114b) described above can also be used.

[0157] Furthermore, a mixed material comprising an organic compound and an electron donor may be used in the electron injection layers (115, 115a, 115b). Such a mixed material exhibits excellent electron injection and electron transport properties because electrons are generated in the organic compound by the electron donor. In this case, the organic compound is preferably a material with excellent electron transport properties, and specifically, for example, electron transport materials (metal complexes and heteroaromatic compounds, etc.) used in the electron transport layers (114, 114a, 114b) described above can be used. The electron donor can be any substance that exhibits electron-donating properties to the organic compound. Specifically, alkali metals, alkaline earth metals, and rare earth metals are preferred, such as lithium, cesium, magnesium, calcium, erbium, and ytterbium. Alkali metal oxides and alkaline earth metal oxides are also preferred, such as lithium oxide, calcium oxide, and barium oxide. Lewis bases such as magnesium oxide can also be used. Furthermore, organic compounds such as tetrathiafulvalene (abbreviated as TTF) can also be used. Furthermore, multiple layers of these materials may be used.

[0158] In addition, a mixed material consisting of an organic compound and a metal may be used for the electron injection layers (115, 115a, 115b). The organic compound used here preferably has a LUMO (Lowest Unoccupied Molecular Orbital) level of -3.6 eV or higher and -2.3 eV or lower. Furthermore, a material having lone pairs of electrons is preferred.

[0159] Therefore, as the organic compound used in the above-mentioned mixed material, a mixed material obtained by mixing a heteroaromatic compound with a metal, as described above for use in an electron transport layer, may be used. Preferred heteroaromatic compounds include materials having lone pairs of electrons, such as heteroaromatic compounds having a 5-membered ring structure (imidazole ring, triazole ring, oxazole ring, oxadiazole ring, thiazole ring, benzimidazole ring, etc.), heteroaromatic compounds having a 6-membered ring structure (pyridine ring, diazine ring (including pyrimidine ring, pyrazine ring, pyridazine ring, etc.), triazine ring, bipyridine ring, terpyridine ring, etc.), and heteroaromatic compounds having a fused ring structure that partially includes a 6-membered ring structure (quinoline ring, benzoquinoline ring, quinoxaline ring, dibenzoquinoxaline ring, phenanthroline ring, etc.). Specific materials have been described above, so further explanation is omitted here.

[0160] Furthermore, it is preferable to use transition metals belonging to Group 5, Group 7, Group 9, or Group 11 of the periodic table and materials belonging to Group 13 as the metals used in the above-mentioned mixed material, such as Ag, Cu, Al, or In. In this case, the organic compound forms a half-occupied orbital (SOMO) with the transition metal.

[0161] For example, when amplifying the light obtained from the light-emitting layer 113b, it is preferable to form the optical distance between the second electrode 102 and the light-emitting layer 113b to be less than 1 / 4 of the wavelength λ of the light emitted by the light-emitting layer 113b. In this case, this can be adjusted by changing the film thickness of the electron transport layer 114b or the electron injection layer 115b.

[0162] Furthermore, as shown in the light-emitting device in Figure 2(D), 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 (also called a tandem structure) can be created.

[0163] <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 (anode) 101 and the second electrode (cathode) 102. The charge generation layer 106 may be configured with electron acceptors added to a hole transport material, or with electron donors added to an electron transport material. Alternatively, both of these configurations may be laminated. By forming the charge generation layer 106 using the materials described above, the increase in driving voltage when the EL layers are laminated can be suppressed.

[0164] In the charge generation layer 106, if an electron acceptor is added to a hole-transporting material which is an organic compound, the material shown in this embodiment can be used as the hole-transporting material. Examples of electron acceptors include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, etc. Other examples include oxides of metals belonging to groups 4 through 8 of the periodic table. Specifically, examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide.

[0165] Furthermore, in the charge generation layer 106, if an electron donor is added to the electron transport material, the material shown in this embodiment can be used as the electron transport material. As the electron donor, alkali metals, alkaline earth metals, rare earth metals, or metals belonging to groups 2 and 13 of the periodic table, as well as their oxides and carbonates, can be used. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, etc., are preferred. Organic compounds such as tetrathianaphthalene may also be used as electron donors.

[0166] Although Figure 2(D) shows a configuration in which two EL layers 103 are stacked, a stacked structure of three or more EL layers may be used by providing a charge generation layer between different EL layers.

[0167] <Circuit board> The light-emitting device shown in this embodiment can be formed on various substrates. The type of substrate is not limited to any particular type. Examples of 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 with stainless steel foil, tungsten substrates, substrates with tungsten foil, flexible substrates, laminated films, paper containing fibrous materials, or base films.

[0168] Examples of glass substrates include barium borosilicate glass, aluminobrosilicate glass, or soda-lime glass. Examples of flexible substrates, laminated films, and base films include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, or polyvinyl chloride, polyamide, polyimide, aramid, epoxy resins, inorganic vapor-deposited films, or paper.

[0169] In this embodiment, the light-emitting device can be fabricated using vapor-phase methods such as vapor deposition, spin coating, and liquid-phase methods such as inkjet. When using vapor deposition, physical vapor deposition methods (PVD) such as sputtering, ion plating, ion beam deposition, molecular beam deposition, and vacuum deposition, or chemical vapor deposition (CVD) can be used. In particular, the various functional layers included in the EL layer of the light-emitting device (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115) can be formed by methods such as vapor deposition (vacuum deposition, etc.), coating (dip coating, die coating, bar coating, spin coating, spray coating, etc.), and printing (inkjet, screen printing, offset printing, flexographic printing, gravure printing, microcontact printing, etc.).

[0170] Furthermore, when applying the above-mentioned coating method, printing method, or other film formation method, polymer compounds (oligomers, dendrimers, polymers, etc.), medium-molecular-weight compounds (compounds in the intermediate region between low-molecular-weight and high-molecular-weight compounds: molecular weight 400 to 4000), inorganic compounds (quantum dot materials, etc.) can be used. As for quantum dot materials, colloidal quantum dot materials, alloy-type quantum dot materials, core-shell type quantum dot materials, core-type quantum dot materials, etc., can be used.

[0171] The layers constituting the EL layer 103 of the light-emitting device shown in this embodiment (hole injection layer 111, hole transport layer 112, light-emitting layer 113, electron transport layer 114, electron injection layer 115) are not limited to the materials shown in this embodiment, and other materials can be used in combination as long as they can satisfy the function of each layer.

[0172] In this specification, the terms "layer" and "film" may be used interchangeably as appropriate.

[0173] The configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0174] (Embodiment 3) This embodiment describes a specific configuration example and manufacturing method of a light-emitting device (also called a display panel) which is one aspect of the present invention.

[0175] <Example of configuration of light-emitting device 700 1> The light-emitting device 700 shown in Figure 3(A) includes light-emitting devices 550B, 550G, 550R, and a partition wall 528. The light-emitting devices 550B, 550G, 550R, and the partition wall 528 are formed on a functional layer 520 provided on a first substrate 510. The functional layer 520 includes drive circuits GD and SD, each composed of multiple transistors, as well as wiring for their electrical connection. These drive circuits are, for example, electrically connected to the light-emitting devices 550B, 550G, and 550R, respectively, and can drive them. The light-emitting device 700 also 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 functional layer 520 to the second substrate 770.

[0176] The light-emitting devices 550B, 550G, and 550R have the device structures shown in Embodiment 1 and Embodiment 2. That is, the EL layer 103 in the structure shown in Figure 2(A) is different for each light-emitting device.

[0177] In this specification, a structure in which different light-emitting layers are created or painted using light-emitting devices of each color (e.g., blue (B), green (G), and red (R)) may be referred to as an SBS (Side By Side) structure. In the light-emitting device 700 shown in Figure 3(A), light-emitting devices 550B, 550G, and 550R are arranged in this order, but one aspect of the present invention is not limited to this configuration. For example, in the light-emitting device 700, these light-emitting devices may be arranged in the order of light-emitting device 550R, light-emitting device 550G, and light-emitting device 550B.

[0178] As shown in Figure 3(A), the light-emitting device 550B has an electrode 551B, an electrode 552, and an EL layer 103B. The specific configuration of each layer is as shown in Embodiment 1 and Embodiment 2. The EL layer 103B has a laminated structure consisting of multiple layers with different functions, including the light-emitting layer. In Figure 3(A), only the hole injection / transport layer 104B, the electron transport layer (108B-1\108B-2) having a laminated structure of a first electron transport layer (108B-1) and a second electron transport layer (108B-2), and the electron injection layer 109 are shown among the layers included in the EL layer 103B including the light-emitting layer, but the present invention is not limited to these. The hole injection / transport layer 104B refers to a layer having the functions of the hole injection layer and hole transport layer as shown in Embodiment 2, and may have a laminated structure. In this specification, the hole injection / transport layer can be interpreted in this way in any light-emitting device.

[0179] The electron transport layer (108B-1\108B-2) has the configuration described in Embodiment 1. It may also have a function to block holes moving from the anode side through the light-emitting layer to the cathode side. Furthermore, the electron injection layer 109 may also have a laminated structure formed using some or all different materials.

[0180] Furthermore, as shown in Figure 3(A), insulating layers 107 may be formed on the sides (or edges) of the holes injection / transport layer 104B, the light-emitting layer, and the electron transport layer (108B-1\108B-2) among the layers included in the EL layer 103B, which includes the light-emitting layer. The insulating layer 107 is formed in contact with the sides (or edges) of the EL layer 103B. This suppresses the intrusion of oxygen and moisture, or substances containing their constituent elements, into the interior from the sides of the EL layer 103B. For example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxide nitride can be used for the insulating layer 107. The insulating layer 107 may also be formed by laminating the aforementioned materials. Sputtering, CVD, MBE, PLD, ALD, etc. can be used to form the insulating layer 107, but the ALD method, which has good coverage, is more preferable.

[0181] Furthermore, an electron injection layer 109 is formed covering a portion of the EL layer 103B (light-emitting layer 113B, hole injection / transport layer 104B, and electron transport layer (108B-1\108B-2)) and the insulating layer 107. The electron injection layer 109 may also be a laminated structure of two or more layers with different electrical resistances within the layers.

[0182] Furthermore, electrode 552 is formed on the electron injection layer 109. Electrode 551B and electrode 552 have overlapping regions. Additionally, an EL layer 103B is present between electrode 551B and electrode 552.

[0183] Furthermore, the EL layer 103B shown in Figure 3(A) has the same configuration as the EL layer 103 described in Embodiment 2. In addition, the EL layer 103B can emit, for example, blue light.

[0184] As shown in Figure 3(A), the light-emitting device 550G has an electrode 551G, an electrode 552, and an EL layer 103G. The specific configuration of each layer is as shown in Embodiment 1 and Embodiment 2. The EL layer 103G has a laminated structure consisting of multiple layers with different functions, including the light-emitting layer. In Figure 3(A), only the hole injection / transport layer 104G, the electron transport layer (108G-1\108G-2) having a laminated structure of a first electron transport layer (108G-1) and a second electron transport layer (108G-2), and the electron injection layer 109 are shown among the layers included in the EL layer 103G including the light-emitting layer, but the present invention is not limited to these. The hole injection / transport layer 104G refers to a layer having the functions of a hole injection layer and a hole transport layer as shown in Embodiment 2, and may have a laminated structure.

[0185] The electron transport layer (108G-1\108G-2) has the configuration described in Embodiment 1. It may also have a function to block holes that move from the anode side through the light-emitting layer to the cathode side. Furthermore, the electron injection layer 109 may also have a laminated structure formed using some or all different materials.

[0186] Furthermore, as shown in Figure 3(A), insulating layers 107 may be formed on the sides (or edges) of the holes injection / transport layer 104G, the light-emitting layer, and the electron transport layer (108G-1\108G-2) among the layers included in the EL layer 103G which contains the light-emitting layer. The insulating layer 107 is formed in contact with the sides (or edges) of the EL layer 103G. This suppresses the penetration of oxygen and moisture, or their constituent elements, into the interior from the sides of the EL layer 103G. For example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon nitride oxide can be used for the insulating layer 107. Also, 107 may be formed by laminating the aforementioned materials. Furthermore, sputtering, CVD, MBE, PLD, ALD, etc. can be used to form the insulating layer 107, but the ALD method, which has good coverage, is more preferable.

[0187] Furthermore, an electron injection layer 109 is formed covering a portion of the EL layer 103G (light-emitting layer 113G, hole injection / transport layer 104G, and electron transport layer (108G-1\108G-2)) and the insulating layer 107. The electron injection layer 109 may also be a laminated structure of two or more layers with different electrical resistances within the layers.

[0188] Furthermore, electrode 552 is formed on the electron injection layer 109. Electrode 551G and electrode 552 have overlapping regions. Additionally, an EL layer 103G is present between electrode 551G and electrode 552.

[0189] Furthermore, the EL layer 103G shown in Figure 3(A) has the same configuration as the EL layer 103 described in Embodiment 2. In addition, the EL layer 103G can emit, for example, green light.

[0190] As shown in Figure 3(A), the light-emitting device 550R has an electrode 551R, an electrode 552, and an EL layer 103R. The specific configuration of each layer is as shown in Embodiment 1 and Embodiment 2. The EL layer 103R has a laminated structure consisting of multiple layers with different functions, including the light-emitting layer 113R. In Figure 3(A), only the hole injection / transport layer 104R, the electron transport layer (108R-1\108R-2) having a laminated structure of a first electron transport layer (108R-1) and a second electron transport layer (108R-2), and the electron injection layer 109 are shown among the layers included in the EL layer 103R including the light-emitting layer, but the present invention is not limited to these. Note that the hole injection / transport layer 104R refers to a layer having the functions of a hole injection layer and a hole transport layer as shown in Embodiment 2, and may have a laminated structure.

[0191] The electron transport layer (108R-1\108R-2) has the configuration described in Embodiment 1. It may also have a function to block holes that move from the anode side through the light-emitting layer to the cathode side. Furthermore, the electron injection layer 109 may also have a laminated structure formed using some or all different materials.

[0192] Furthermore, as shown in Figure 3(A), insulating layers 107 may be formed on the sides (or edges) of the holes injection / transport layer 104R, the light-emitting layer, and the electron transport layer (108R-1\108R-2) among the layers included in the EL layer 103R, which includes the light-emitting layer. The insulating layer 107 is formed in contact with the sides (or edges) of the EL layer 103R. This suppresses the penetration of oxygen and moisture, or their constituent elements, into the interior from the sides of the EL layer 103R. For example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon oxide nitride can be used for the insulating layer 107. The insulating layer 107 may also be formed by laminating the aforementioned materials. Sputtering, CVD, MBE, PLD, ALD, etc. can be used to form the insulating layer 107, but the ALD method, which has good coverage, is more preferable.

[0193] Furthermore, an electron injection layer 109 is formed covering a portion of the EL layer 103R (the light-emitting layer, the hole injection / transport layer 104R, and the electron transport layer (108R-1\108R-2)) and the insulating layer 107. The electron injection layer 109 may also be a laminated structure of two or more layers with different electrical resistances within the layers.

[0194] Furthermore, electrode 552 is formed on the electron injection layer 109. Electrode 551R and electrode 552 have overlapping regions. Additionally, an EL layer 103R is present between electrode 551R and electrode 552.

[0195] Furthermore, the EL layer 103R shown in Figure 3(A) has the same configuration as the EL layer 103 described in Embodiment 2. In addition, the EL layer 103R can emit, for example, red light.

[0196] There is a partition wall 528 between each of the EL layers 103B, 103G, and 103R. As shown in Figure 3(A), the EL layers of each light-emitting device (EL layer 103B, EL layer 103G, EL layer 103R) and the partition wall 528 are in contact at the sides (or ends) via the insulating layer 107.

[0197] In each EL layer, the hole injection layer, particularly the hole transport region located between the anode and the light-emitting layer, often has high conductivity. Therefore, if it is formed as a common layer for adjacent light-emitting devices, it can cause crosstalk. Accordingly, as shown in this example configuration, by providing a partition wall 528 made of insulating material between each EL layer, it is possible to suppress the occurrence of crosstalk between adjacent light-emitting devices.

[0198] Furthermore, in the manufacturing method described in this embodiment, the side (or edge) of the EL layer is exposed during the patterning process. As a result, the EL layer is more susceptible to deterioration due to the intrusion of oxygen and water from the side (or edge) of the EL layer. Therefore, by providing the partition wall 528, it is possible to suppress the deterioration of the EL layer during the manufacturing process.

[0199] Furthermore, by providing the partition wall 528, it is possible to flatten the recess formed between adjacent light-emitting devices. Flattening the recess helps to suppress disconnection of the electrodes 552 formed on each EL layer. As the insulating material used to form the partition wall 528, organic materials such as acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimidoamide resin, silicon resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins can be used. Alternatively, organic materials such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin may be used. Photosensitive resins such as photoresists can also be used. The photosensitive resin can be either a positive-type or negative-type material.

[0200] By using a photosensitive resin, the partition wall 528 can be fabricated using only the exposure and development processes. Alternatively, the partition wall 528 may be formed using a negative-type photosensitive resin (e.g., a resist material). Furthermore, when an insulating layer having an organic material is used as the partition wall 528, it is preferable to use a material that absorbs visible light. By using a material that absorbs visible light for the partition wall 528, the light emitted from the EL layer can be absorbed by the partition wall 528, thereby suppressing light (stray light) that may leak into adjacent EL layers. Therefore, a display panel with high display quality can be provided.

[0201] Furthermore, the difference between the height of the upper surface of the partition wall 528 and the height of the upper surface of any of the EL layers 103B, EL layer 103G, and EL layer 103R is preferably 0.5 times or less the thickness of the partition wall 528, and more preferably 0.3 times or less. Also, for example, the partition wall 528 may be provided such that the upper surface of any of the EL layers 103B, EL layer 103G, and EL layer 103R is higher than the upper surface of the partition wall 528. Also, for example, the partition wall 528 may be provided such that the upper surface of the partition wall 528 is higher than the upper surface of the light-emitting layer of the EL layer 103B, EL layer 103G, and EL layer 103R.

[0202] In a high-resolution light-emitting device (display panel) with a resolution exceeding 1000 ppi, if electrical conductivity is detected between the EL layer 103B, EL layer 103G, and EL layer 103R, a crosstalk phenomenon occurs, narrowing the color gamut that the light-emitting device can display. By providing a partition wall 528 in a high-resolution display panel exceeding 1000 ppi, preferably a high-resolution display panel exceeding 2000 ppi, and more preferably an ultra-high-resolution display panel exceeding 5000 ppi, a display panel capable of displaying vivid colors can be provided.

[0203] Furthermore, Figures 3(B) and 3(C) show schematic top views of the light-emitting device 700 corresponding to the dashed line Ya-Yb in the cross-sectional view of Figure 3(A). That is, light-emitting devices 550B, 550G, and 550R are arranged in a matrix. Figure 3(B) shows a so-called stripe arrangement in which light-emitting devices of the same color are arranged in the X direction. In the Y direction, which intersects with the X direction, light-emitting devices of different colors are arranged. Note that the arrangement method of the light-emitting devices is not limited to this, and arrangement methods such as delta arrangement and zigzag arrangement may be applied, or pentile arrangement and diamond arrangement may be used.

[0204] Furthermore, since the separation process of each EL layer (EL layer 103B, EL layer 103G, and EL layer 103R) is performed using photolithography to form patterns, a high-definition light-emitting device (display panel) can be manufactured. In addition, the edges (sides) of the EL layers processed by the photolithography pattern formation have a shape that is substantially the same surface (or substantially located on the same plane). At this time, the width (SE) of the gap 580 between each EL layer is preferably 5 μm or less, and more preferably 1 μm or less.

[0205] In EL layers, the hole injection layer, particularly the hole transport region located between the anode and the light-emitting layer, often has high conductivity. Therefore, if it is formed as a common layer for adjacent light-emitting devices, it can cause crosstalk. Consequently, by separating the EL layer using photolithography, as shown in this example configuration, it is possible to suppress the occurrence of crosstalk between adjacent light-emitting devices.

[0206] Furthermore, Figure 3(D) is a schematic cross-sectional view corresponding to the dashed line C1-C2, which includes region 150 in Figures 3(B) and 3(C). Figure 3(D) shows a connection portion 130 where the connecting electrode 551C and electrode 552 are electrically connected. At the connection portion 130, electrode 552 is provided in contact with the connecting electrode 551C. In addition, a partition wall 528 is provided covering the end of the connecting electrode 551C.

[0207] <Example 1 of a manufacturing method for a light-emitting device> As shown in Figure 4(A), electrodes 551B, 551G, and 551R are formed. For example, a conductive film is formed on a functional layer 520 formed on the first substrate 510, and then processed into a predetermined shape using photolithography.

[0208] Conductive films can be formed using methods such as sputtering, chemical vapor deposition (CVD), molecular beam epitaxy (MBE), vacuum deposition, pulsed laser deposition (PLD), and atomic layer deposition (ALD). CVD methods include plasma-enhanced CVD (PECVD) and thermal CVD. One type of thermal CVD is metal-organic CVD (MOCVD).

[0209] In addition to the photolithography method described above, conductive films may also be processed using nanoimprint lithography, sandblasting, lift-off methods, etc. Island-like thin films may also be directly formed using a film deposition method that utilizes a shielding mask such as a metal mask.

[0210] There are two main methods of photolithography. One method involves forming a resist mask on a thin film to be processed, processing the thin film by etching or other means, and then removing the resist mask. The other method involves forming a photosensitive thin film, then exposing and developing it to process the thin film into a desired shape. The former method involves heat treatment steps such as heating after resist coating (PAB: Pre-Applied Bake) and heating after exposure (PEB: Post-Exposure Bake). In one aspect of the present invention, lithography is used not only for processing conductive films but also for processing thin films (films made of organic compounds, or films containing organic compounds in part) used to form an EL layer.

[0211] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture thereof. Other options include ultraviolet light, KrF laser light, or ArF laser light. Exposure may also be performed using immersion lithography. Furthermore, extreme ultraviolet (EUV) light or X-rays may be used as the light source for exposure. An electron beam can also be used instead of light for exposure. Using extreme ultraviolet light, X-rays, or an electron beam is preferable because it allows for extremely fine processing. Note that a photomask is not required when exposure is performed by scanning a beam such as an electron beam.

[0212] For etching thin films using a resist mask, methods such as dry etching, wet etching, and sandblasting can be used.

[0213] Next, as shown in Figure 4(B), a portion of the EL layer 103B is formed on electrodes 551B, 551G, and 551R. In Figure 4(B), the EL layer 103B includes the hole injection / transport layer 104B, the light-emitting layer 113B, and the electron transport layer (108B-1 / 108B-2). These portions of the EL layer 103B can be formed, for example, using a vacuum deposition method, on electrodes 551B, 551G, and 551R, covering them. Furthermore, a sacrificial layer 110B is formed on the electron transport layer (108B-1 / 108B-2), which is part of the EL layer 103B.

[0214] The sacrificial layer 110B can be a film with high resistance to etching of the EL layer 103B, i.e., a film with a high etching selectivity ratio. Furthermore, it is preferable that the sacrificial layer 110B has a laminated structure of a first sacrificial layer and a second sacrificial layer with different etching selectivity ratios. Additionally, the sacrificial layer 110B can be a film that can be removed by a wet etching method that causes minimal damage to the EL layer 103B. Oxalic acid can be used as the etching material for wet etching.

[0215] As the sacrificial layer 110B, for example, an inorganic film such as a metal film, alloy film, metal oxide film, semiconductor film, or inorganic insulating film can be used. Furthermore, the sacrificial layer 110B can be formed by various film deposition methods such as sputtering, vapor deposition, CVD, and ALD.

[0216] As the sacrificial layer 110B, metal materials such as gold, silver, platinum, magnesium, nickel, tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, titanium, aluminum, yttrium, zirconium, and tantalum, or alloy materials containing such metal materials, can be used. In particular, it is preferable to use low-melting-point materials such as aluminum or silver.

[0217] Furthermore, metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also written as IGZO) can be used as the sacrificial layer 110B. In addition, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can be used. Alternatively, indium tin oxide containing silicon can also be used.

[0218] Furthermore, element M (where M is one or more selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, or magnesium) may be used instead of gallium. In particular, it is preferable that M be one or more selected from gallium, aluminum, or yttrium.

[0219] Furthermore, inorganic insulating materials such as aluminum oxide, hafnium oxide, and silicon oxide can be used as the sacrificial layer 110B.

[0220] Furthermore, it is preferable to use a material that is soluble in a solvent that is at least chemically stable to the EL layer 103B and is located at the top (electron transport layer (108B-1\108B-2)) as the sacrificial layer 110B. In particular, a material that is soluble in water or alcohol can be suitably used for the sacrificial layer 110B. When forming the sacrificial layer 110B, it is preferable to dissolve the material in a solvent such as water or alcohol, apply it using a wet deposition method, and then perform a heat treatment to evaporate the solvent. At this time, performing the heat treatment under a reduced pressure atmosphere is preferable because it allows the solvent to be removed at a low temperature and in a short time, thereby reducing thermal damage to a part of the EL layer 103B.

[0221] Furthermore, when the sacrificial layer 110B is to be made into a laminated structure, the layer formed from the above-mentioned material can be designated as the first sacrificial layer, and a second sacrificial layer can be formed on top of it to create a laminated structure.

[0222] In this case, the second sacrificial layer is a film used as a hard mask when etching the first sacrificial layer. Furthermore, the first sacrificial layer is exposed during processing of the second sacrificial layer. Therefore, the first and second sacrificial layers are selected based on a combination of films that have a high etching selectivity ratio for each other. Thus, the film that can be used for the second sacrificial layer can be selected according to the etching conditions for both the first and second sacrificial layers.

[0223] For example, when dry etching using a fluorine-containing gas (also called a fluorine-based gas) is used for etching the second sacrificial layer, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, alloys containing molybdenum and niobium, or alloys containing molybdenum and tungsten can be used for the second sacrificial layer. Here, metal oxide films such as IGZO and ITO can be used for the first sacrificial layer as films that allow for a higher selectivity ratio for etching (i.e., a slower etching rate) compared to dry etching using the above-mentioned fluorine-based gas.

[0224] However, the second sacrificial layer can be selected from a variety of materials, depending on the etching conditions of the first sacrificial layer and the etching conditions of the second sacrificial layer. For example, it can be selected from among the films that can be used for the first sacrificial layer.

[0225] Furthermore, a nitride film can be used as the second sacrificial layer. Specifically, nitrides such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, and germanium nitride can be used.

[0226] Alternatively, an oxide film can be used as the second sacrificial layer. Typically, oxide films or oxynitride films such as silicon oxide, silicon oxynitride, aluminum oxide, aluminum oxynitride, hafnium oxide, and hafnium oxynitride can be used.

[0227] Next, as shown in Figure 4(C), a resist is applied to the sacrificial layer 110B, and the resist is formed into the desired shape (resist mask: REG) using photolithography. Note that this method involves heat treatment steps such as heating after resist application (PAB: Pre-Applied Bake) and heating after exposure (PEB: Post-Exposure Bake). For example, the PAB temperature is around 100°C, and the PEB temperature is around 120°C. Therefore, the light-emitting device must be able to withstand these processing temperatures.

[0228] Next, using the obtained resist mask REG, a portion of the sacrificial layer 110B not covered by the resist mask REG is removed by etching. After removing the resist mask REG, a portion of the EL layer 103B not covered by the sacrificial layer 110B is removed by etching. The EL layer 103B on electrode 551G and the EL layer 103B on electrode 551R are removed by etching to process the material into a shape with sides (or with exposed sides) or a strip shape extending in a direction intersecting the plane of the paper. Specifically, dry etching is performed using the sacrificial layer 110B with a pattern formed on the EL layer 103B overlapping electrode 551B. If the sacrificial layer 110B has a laminated structure with the first sacrificial layer and the second sacrificial layer, a portion of the second sacrificial layer may be etched with the resist mask REG, then the resist mask REG is removed, and the second sacrificial layer is used as a mask to etch a portion of the first sacrificial layer and process the EL layer 103B into a predetermined shape. These etching processes yield the shape shown in Figure 5(A).

[0229] Next, as shown in Figure 5(B), a portion of the EL layer 103G is formed on the sacrificial layer 110B, electrode 551G, and electrode 551R. In Figure 5(B), the EL layer 103G is formed up to the hole injection / transport layer 104G, the light-emitting layer 113G, and the electron transport layer (108G-1\108G-2). These EL layers 103G can be formed, for example, by vacuum deposition on the sacrificial layer 110B, electrode 551G, and electrode 551R, covering them.

[0230] Next, as shown in Figure 5(C), a sacrificial layer 110G is formed on the electron transport layer (108G-1\108G-2), which is part of the EL layer 103G. A resist is applied on the sacrificial layer 110G, and the resist is formed into a desired shape (resist mask: REG) using photolithography. A portion of the sacrificial layer 110G not covered by the obtained resist mask is removed by etching. After removing the resist mask, a portion of the EL layer 103G not covered by the sacrificial layer is removed by etching. A portion of the EL layer 103G on electrode 551B and a portion of the EL layer 103G on electrode 551R are removed by etching to process the material into a shape with sides (or exposed sides), or a strip shape extending in a direction intersecting the plane of the paper, as shown in Figure 6(A). Furthermore, if the sacrificial layer 110G has a laminated structure with the first sacrificial layer and the second sacrificial layer described above, a portion of the second sacrificial layer may be etched with a resist mask, then the resist mask may be removed, and the second sacrificial layer may be used as a mask to etch a portion of the first sacrificial layer, thereby processing a portion of the EL layer 103G into a predetermined shape.

[0231] Next, as shown in Figure 6(B), a portion of the EL layer 103R is formed on the sacrificial layer 110B, the sacrificial layer 110G, and the electrode 551R. In Figure 6(B), the EL layer 103R includes the hole injection / transport layer 104R, the light-emitting layer, and the electron transport layer (108R-1\108R-2). These portions of the EL layer 103R can be formed, for example, by vacuum deposition on the sacrificial layer 110B, the sacrificial layer 110G, and the electrode 551R, covering them.

[0232] Next, as shown in Figure 6(C), a sacrificial layer 110R is formed on the electron transport layer (108R-1\108R-2), which is part of the EL layer 103R. A resist is applied on the sacrificial layer 110R, and the resist is formed into a desired shape (resist mask: REG) using photolithography. A portion of the sacrificial layer 110R not covered by the obtained resist mask is removed by etching. After removing the resist mask, a portion of the EL layer 103R not covered by the sacrificial layer is removed by etching. A portion of the EL layer 103R on electrode 551B and a portion of the EL layer 103R on electrode 551G are removed by etching to process the material into a shape with sides (or with exposed sides) or a strip shape extending in a direction intersecting the paper plane. Furthermore, if the sacrificial layer 110G has a laminated structure with the first sacrificial layer and the second sacrificial layer, a portion of the second sacrificial layer may be etched with a resist mask, then the resist mask may be removed, and the second sacrificial layer may be used as a mask to etch a portion of the first sacrificial layer, thereby processing a portion of the EL layer 103G into a predetermined shape. In addition, while leaving the sacrificial layers (110B, 110G, 110R) on the EL layers (103B, 103G, 103R) intact, an insulating layer 107 is formed on the sacrificial layers (110B, 110G, 110R) to obtain the shape shown in Figure 7(A).

[0233] For example, the ALD method can be used to form the insulating layer 107. In this case, the insulating layer 107 is formed in contact with the side surfaces of each EL layer (103B, 103G, 103R), as shown in Figure 7(A). This suppresses the penetration of oxygen and moisture, or their constituent elements, into the interior from the side surfaces of each EL layer (103B, 103G, 103R). As for the material used for the insulating layer 107, for example, aluminum oxide, magnesium oxide, hafnium oxide, gallium oxide, indium gallium zinc oxide, silicon nitride, or silicon nitride oxide can be used.

[0234] Next, as shown in Figure 7(B), after removing the sacrificial layers (110B, 110G, 110R), a partition wall 528 is formed on the insulating layer (107B, 107G, 107R), and an electron injection layer 109 is formed on the partition wall 528 and the electron transport layers (108B-1\108B-2, 108G-1\108G-2, 108R-1\108R-2). The electron injection layer 109 is formed, for example, using a vacuum deposition method. Note that the electron injection layer 109 is formed on the electron transport layers (108B-1\108B-2, 108G-1\108G-2, 108R-1\108R-2). Furthermore, the electron injection layer 109 has a structure in which it is in contact with the hole injection / transport layers (104R, 104G, 104B), light-emitting layers (113R, 113G, 113B), and electron transport layers (108B-1\108B-2, 108G-1\108G-2, 108R-1\108R-2), which are part of each EL layer (103B, 103G, 103R), via an insulating layer (107B, 107G, 107R) at its side surface (or end).

[0235] Next, as shown in Figure 7(C), an electrode 552 is formed. The electrode 552 is formed, for example, by vacuum deposition. The electrode 552 is formed on the electron injection layer 109. The electrode 552 has a structure that contacts the side (or edge) of each EL layer (103B, 103G, 103R) (however, the EL layers (103B, 103G, 103R) shown in Figure 7(C) include hole injection / transport layers (104R, 104G, 104B), an emissive layer, and electron transport layers (108B-1\108B-2, 108G-1\108G-2, 108R-1\108R-2)) via the electron injection layer 109 and insulating layers (107B, 107G, 107R). This prevents electrical short circuits between each EL layer (103B, 103G, 103R) and the electrode 552, or more specifically, between the hole injection / transport layers (104B, 104G, 104R) of each EL layer (103B, 103G, 103R) and the electrode 552.

[0236] Through the above process, the EL layers 103B, 103G, and 103R of the light-emitting devices 550B, 550G, and 550R can be separated.

[0237] Furthermore, since the separation process of these EL layers (EL layer 103B, EL layer 103G, and EL layer 103R) is performed using photolithography to form patterns, a high-definition light-emitting device (display panel) can be manufactured. In addition, the edges (sides) of the EL layers processed by photolithography have a shape that is substantially the same surface (or is located substantially on the same plane).

[0238] In EL layers, the hole injection layer, particularly the hole transport region located between the anode and the light-emitting layer, often has high conductivity. Therefore, if it is formed as a common layer for adjacent light-emitting devices, it can cause crosstalk. Consequently, by separating the EL layer using photolithography, as shown in this example configuration, it is possible to suppress the occurrence of crosstalk between adjacent light-emitting devices.

[0239] <Example of configuration of light-emitting device 700 2> The light-emitting device 700 shown in Figure 8 includes light-emitting devices 550B, 550G, 550R, and a partition wall 532. The light-emitting devices 550B, 550G, 550R, and the partition wall 532 are formed on a functional layer 520 provided on a first substrate 510. The functional layer 520 includes drive circuits GD and SD, each composed of multiple transistors, as well as wiring to electrically connect them. These drive circuits are, for example, electrically connected to and capable of driving the light-emitting devices 550B, 550G, and 550R, respectively.

[0240] The light-emitting devices 550B, 550G, and 550R have the device structures shown in Embodiment 1 and Embodiment 2. In particular, Figure 2(A) shows a case where the EL layer 103 in the structure shown differs for each light-emitting device.

[0241] The specific configurations of each light-emitting device shown in Figure 8 are the same as those of light-emitting devices 550B, 550G, and 550R described in Figure 3.

[0242] As shown in Figure 8, each light-emitting device (550B, 550G, 550R) has an EL layer (103B, 103G, 103R) which includes a hole injection / transport layer (104B, 104G, 104R), a light-emitting layer (113B, 113G, 113R), an electron transport layer (108B-1\108B-2, 108G-1\108G-2, 108R-1\108R-2), and an electron injection layer 109, respectively.

[0243] Furthermore, since each EL layer in this configuration (EL layer 103B, EL layer 103G, and EL layer 103R) is patterned using photolithography during the separation process, the edges (sides) of the processed EL layers have a shape in which they are approximately the same surface (or are located on approximately the same plane).

[0244] Each light-emitting device has an EL layer (EL layer 103B, EL layer 103G, and EL layer 103R) with a gap 580 between adjacent light-emitting devices. Here, if the gap 580 is expressed as SE as the distance between the EL layers of adjacent light-emitting devices, a smaller distance SE allows for a higher aperture ratio and higher resolution. On the other hand, a larger distance SE allows for greater tolerance of manufacturing process variations between adjacent light-emitting devices, thereby increasing the manufacturing yield. Since the light-emitting devices manufactured according to this specification are suitable for miniaturization processes, the distance SE between the EL layers of adjacent light-emitting devices can be 0.5 μm or more and 5 μm or less, preferably 1 μm or more and 3 μm or less, more preferably 1 μm or more and 2.5 μm or less, and even more preferably 1 μm or more and 2 μm or less. Typically, the distance SE is preferably 1 μm or more and 2 μm or less (for example, 1.5 μm or nearby).

[0245] In EL layers, the hole injection layer, particularly the hole transport region located between the anode and the light-emitting layer, often has high conductivity. Therefore, if it is formed as a common layer for adjacent light-emitting devices, it can cause crosstalk. Consequently, by separating the EL layer using photolithography, as shown in this example configuration, it is possible to suppress the occurrence of crosstalk between adjacent light-emitting devices.

[0246] In this specification, devices fabricated using a metal mask or FMM (Fine Metal Mask, a high-resolution metal mask) may be referred to as MM (Metal Mask) structured devices. Furthermore, in this specification, devices fabricated without using a metal mask or FMM may be referred to as MML (Metal Maskless) structured devices. Because MML structured light-emitting devices are fabricated without a metal mask, they offer greater design flexibility in terms of pixel arrangement and pixel shape compared to FMM or MM structured light-emitting devices.

[0247] Furthermore, the island-shaped EL layers in MML structured light-emitting devices are not formed by the pattern on the metal mask, but rather by processing after the EL layer has been deposited. Therefore, it is possible to realize light-emitting devices with higher resolution or higher aperture ratios than before. In addition, since the EL layer can be manufactured separately for each color, it is possible to realize light-emitting devices with extremely vivid colors, high contrast, and high display quality. Moreover, by providing a sacrificial layer on top of the EL layer, the damage the EL layer receives during the manufacturing process can be reduced, thereby increasing the reliability of the light-emitting device.

[0248] In the case of processing the above light-emitting layer into an island shape, a structure in which the EL layer laminated up to the light-emitting layer is processed using a photolithography method can be considered. In the case of such a structure, the light-emitting layer may be damaged (such as damage caused by processing), and the reliability may be significantly impaired. Therefore, when manufacturing the display panel according to one aspect of the present invention, it is preferable to use a method in which a sacrificial layer or the like is formed on a layer located above the light-emitting layer (for example, a carrier transport layer or a carrier injection layer, more specifically, an electron transport layer or an electron injection layer, etc.) and the light-emitting layer is processed into an island shape. By applying this method, a highly reliable display panel can be provided.

[0249] The configuration shown in the present embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0250] (Embodiment 4) In the present embodiment, the apparatus 720 will be described with reference to FIGS. 9 to 11. The apparatus 720 shown in FIGS. 9 to 11 is a light-emitting device because it has the light-emitting devices shown in Embodiment 1 and Embodiment 2. However, the apparatus 720 described in the present embodiment can also be referred to as a display panel or a display device because it can be applied to a display unit of an electronic device or the like. Further, in the case of a configuration including the above light-emitting device as a light source and a light-receiving device capable of receiving light from the light-emitting device, it can also be referred to as a light-emitting and light-receiving device. These light-emitting devices, display panels, display devices, and light-emitting and light-receiving devices are configured to have at least a light-emitting device.

[0251] Furthermore, the light-emitting device, display panel, display device, and light-receiving device of this embodiment can be high-resolution or large-screen. Therefore, the light-emitting device, display panel, display device, and light-receiving device of this embodiment can be used in electronic devices with relatively large screens, such as television systems, desktop or notebook personal computers, computer monitors, digital signage, and large game machines such as pachinko machines, as well as in the display units of digital cameras, digital video cameras, digital photo frames, mobile phones, portable game consoles, smartphones, smartwatches, tablet devices, personal information terminals, and audio playback devices.

[0252] Figure 9(A) shows a top view of these devices (including light-emitting devices, display panels, display devices, and light-receiving devices) 720.

[0253] In Figure 9(A), the device 720 has a configuration in which substrates 710 and 711 are bonded together. The device 720 also has a display area 701, a circuit 704, and wiring 706, etc. The display area 701 has multiple pixels, and as shown in Figure 9(A), pixel 703(i,j) has an adjacent pixel 703(i+1,j) as shown in Figure 9(B).

[0254] Furthermore, as shown in Figure 9(A), the device 720 shows an example in which an IC (integrated circuit) 712 is provided on the substrate 710 using a COG (Chip On Glass) method or a COF (Chip On Film) method. For example, an IC having a scan line drive circuit or a signal line drive circuit can be used as IC 712. Figure 9(A) shows a configuration in which an IC having a signal line drive circuit is used as IC 712, and circuit 704 has a scan line drive circuit.

[0255] The wiring 706 has the function of supplying signals and power to the display area 701 and the circuit 704. These signals and power are input to the wiring 706 from an external source via the FPC (Flexible Printed Circuit) 713, or from the IC 712. The device 720 may be configured without an IC. Alternatively, the IC may be mounted on the FPC using a COF (Cable Oven) method or the like.

[0256] Figure 9(B) shows pixels 703(i,j) and 703(i+1,j) of the display area 701. That is, pixel 703(i,j) can be configured to have multiple subpixels, each having a light-emitting device that emits a different color. Alternatively, in addition to the above, it can also be configured to include multiple subpixels having light-emitting devices that emit the same color. For example, a pixel can be configured to have three types of subpixels. Examples of these three subpixels include subpixels of three colors: red (R), green (G), and blue (B); or subpixels of three colors: yellow (Y), cyan (C), and magenta (M). Alternatively, a pixel can be configured to have four types of subpixels. Examples of these four subpixels include subpixels of four colors: R, G, B, and white (W); or subpixels of four colors: R, G, B, and Y. Specifically, it can be a pixel 703(i,j) composed of sub-pixels 702B(i,j) that display blue, sub-pixels 702G(i,j) that display green, and sub-pixels 702R(i,j) that display red.

[0257] Furthermore, the sub-pixel may be configured to have not only a light-emitting device but also a light-receiving device. When the sub-pixel is configured to have a light-receiving device, the device 720 is also called a light-receiving device.

[0258] Figures 9(C) to 9(F) show pixel 703(i,j) which includes a sub-pixel 702PS(i,j) with a light-receiving device, illustrating various layout examples. The pixel arrangement shown in Figure 9(C) is a stripe arrangement, and the pixel arrangement shown in Figure 9(D) is a matrix arrangement. The pixel arrangement shown in Figure 9(E) has a configuration where three sub-pixels (sub-pixel R, sub-pixel G, and sub-pixel PS) are arranged vertically next to one sub-pixel (sub-pixel B). The pixel arrangement shown in Figure 9(F) has a configuration where three vertically elongated sub-pixels G, B, and R are arranged horizontally, with sub-pixel PS and a horizontally elongated sub-pixel IR arranged horizontally below them. The wavelength of light detected by sub-pixel 702PS(i,j) is not particularly limited, but it is preferable that the light-receiving device of sub-pixel 702PS(i,j) is sensitive to the light emitted by the light-emitting device of sub-pixel 702R(i,j), sub-pixel 702G(i,j), sub-pixel 702B(i,j), or sub-pixel 702IR(i,j). For example, it is preferable to detect one or more of the following wavelengths: blue, violet, blue-violet, green, yellow-green, yellow, orange, red, and infrared.

[0259] Furthermore, as shown in Figure 9(F), a sub-pixel 702IR(i,j) that emits infrared light may be added to the above pair and designated as pixel 703(i,j). Specifically, a sub-pixel that emits light including light with a wavelength of 650 nm to 1000 nm may be used as pixel 703(i,j).

[0260] Furthermore, the arrangement of subpixels is not limited to the configuration shown in Figure 9, and various methods can be applied. Examples of subpixel arrangements include stripe arrangements, S-stripe arrangements, matrix arrangements, delta arrangements, Bayer arrangements, and pentile arrangements.

[0261] Furthermore, the top surface shape of a sub-pixel can be, for example, a triangle, a quadrilateral (including rectangles and squares), a pentagon, or other polygons with rounded corners, an ellipse, or a circle. The top surface shape of a sub-pixel referred to here corresponds to the top surface shape of the light-emitting area of ​​a light-emitting device.

[0262] Furthermore, if the pixel is configured to have both a light-emitting device and a light-receiving device, the pixel has a light-receiving function, allowing it to detect contact or proximity of an object while displaying an image. For example, instead of displaying an image with all of the subpixels of the light-emitting device, some of the subpixels can emit light as a light source, while the remaining subpixels display an image.

[0263] Furthermore, it is preferable that the light-receiving area of ​​the sub-pixel 702PS(i,j) is smaller than the light-emitting area of ​​the other sub-pixels. The smaller the light-receiving area, the narrower the imaging range, which allows for suppression of blur in the imaging result and improvement of resolution. Therefore, by using the sub-pixel 702PS(i,j), high-definition or high-resolution imaging can be performed. For example, the sub-pixel 702PS(i,j) can be used to perform imaging for personal authentication using fingerprints, palm prints, irises, pulse patterns (including vein patterns and arterial patterns), or faces.

[0264] Furthermore, the sub-pixel 702PS(i,j) can be used as a touch sensor (also called a direct touch sensor) or a near-touch sensor (also called a hover sensor, hover-touch sensor, non-contact sensor, or touchless sensor). For example, it is preferable that the sub-pixel 702PS(i,j) detect infrared light. This enables touch detection even in dark places.

[0265] Here, a touch sensor or near-touch sensor can detect the proximity or contact of an object (such as a finger, hand, or pen). A touch sensor can detect an object when the light-receiving device and the object are in direct contact. A near-touch sensor can detect an object even if the object does not come into contact with the light-receiving device. For example, it is preferable that the light-receiving device can detect an object when the distance between the light-receiving device and the object is in the range of 0.1 mm to 300 mm, preferably 3 mm to 50 mm. With this configuration, it becomes possible to operate the light-receiving device without the object directly touching it, in other words, it becomes possible to operate the light-receiving device without contact (touchless). With the above configuration, the risk of the light-receiving device becoming dirty or scratched can be reduced, or it becomes possible to operate the light-receiving device without the object directly touching any dirt (e.g., dust, bacteria, or viruses) attached to the display device.

[0266] Furthermore, in order to perform high-resolution imaging, it is preferable that sub-pixels 702PS(i,j) be provided on all pixels of the light-receiving device. On the other hand, when sub-pixels 702PS(i,j) are used in touch sensors or near-touch sensors, the accuracy required is not as high as when imaging fingerprints, so it is sufficient to provide them on some of the pixels of the light-receiving device. The detection speed can be increased by reducing the number of sub-pixels 702PS(i,j) in the light-receiving device to the number of sub-pixels 702R(i,j), etc.

[0267] Next, an example of a pixel circuit for a subpixel having a light-emitting device will be explained with reference to Figure 10(A). The pixel circuit 530 shown in Figure 10(A) has a light-emitting device (EL) 550, transistors M15, M16, M17, and a capacitive element C3. A light-emitting diode can be used as the light-emitting device 550. In particular, it is preferable to use the light-emitting device described in Embodiment 1 and Embodiment 2 as the light-emitting device 550.

[0268] In Figure 10(A), transistor M15 has its gate electrically connected to wiring VG, one of its source or drain electrically connected to wiring VS, and the other of its source or drain electrically connected to one electrode of capacitive element C3 and the gate of transistor M16. One of the source or drain of transistor M16 is electrically connected to wiring V4, and the other is electrically connected to the anode of light-emitting device 550 and one of the source or drain of transistor M17. Transistor M17 has its gate electrically connected to wiring MS, and the other of its source or drain electrically connected to wiring OUT2. The cathode of light-emitting device 550 is electrically connected to wiring V5.

[0269] Constant potentials are supplied to wiring V4 and wiring V5, respectively. The anode side of the light-emitting device 550 can be set to a high potential, and the cathode side to a lower potential than the anode side. Transistor M15 is controlled by a signal supplied to wiring VG and functions as a selection transistor to control the selected state of the pixel circuit 530. Transistor M16 also functions as a drive transistor that controls the current flowing to the light-emitting device 550 according to the potential supplied to its gate. When transistor M15 is conducting, the potential supplied to wiring VS is supplied to the gate of transistor M16, and the luminescence brightness of the light-emitting device 550 can be controlled according to that potential. Transistor M17 is controlled by a signal supplied to wiring MS and has the function of outputting the potential between transistor M16 and the light-emitting device 550 to the outside via wiring OUT2.

[0270] Furthermore, it is preferable to use transistors in which the semiconductor layer on which the channel is formed is made of metal oxide (oxide semiconductor) for transistors M11, M12, M13, and M14, as well as transistors M15, M16, and M17, which are located in the pixel circuit 530 in Figure 10(A).

[0271] Transistors using metal oxides with a wider bandgap and lower carrier density than silicon can achieve an extremely small off-current. Therefore, due to this small off-current, it is possible to hold the charges accumulated in the capacitive element connected in series with the transistor over a long period of time. Therefore, particularly for transistors M11, M12, and M15 connected in series to capacitive element C2 or capacitive element C3, it is preferable to use transistors with an oxide semiconductor applied. Also, for other transistors as well, the manufacturing cost can be reduced by using transistors with an oxide semiconductor applied.

[0272] Also, transistors M11 to M17 can use transistors with silicon applied to the semiconductor in which the channel is formed. Particularly, by using highly crystalline silicon such as single crystal silicon or polycrystalline silicon, high field-effect mobility can be achieved, enabling faster operation, which is preferable.

[0273] Also, among transistors M11 to M17, a configuration may be adopted in which transistors with an oxide semiconductor applied are used for one or more of them, and transistors with silicon applied are used for the rest.

[0274] Next, an example of a pixel circuit of a sub-pixel having a light-receiving device will be described with reference to FIG. 10(B). The pixel circuit 531 shown in FIG. 10(B) includes a light-receiving device (PD) 560, transistors M11, M12, M13, M14, and a capacitive element C2. Here, an example using a photodiode is shown as the light-receiving device (PD) 560.

[0275] In Figure 10(B), the photodetector (PD) 560 has its anode electrically connected to wiring V1 and its cathode electrically connected to either the source or drain of transistor M11. Transistor M11 has its gate electrically connected to wiring TX and its other source or drain electrically connected to one electrode of capacitive element C2, one source or drain of transistor M12, and the gate of transistor M13. Transistor M12 has its gate electrically connected to wiring RES and its other source or drain electrically connected to wiring V2. Transistor M13 has its source or drain electrically connected to wiring V3 and its other source or drain electrically connected to either the source or drain of transistor M14. Transistor M14 has its gate electrically connected to wiring SE1 and its other source or drain electrically connected to wiring OUT1.

[0276] Constant potentials are supplied to wirings V1, V2, and V3, respectively. When the photodetector (PD) 560 is driven in reverse bias, a higher potential is supplied to wiring V2 than to wiring V1. Transistor M12 is controlled by a signal supplied to wiring RES and has the function of resetting the potential of the node connected to the gate of transistor M13 to the potential supplied to wiring V2. Transistor M11 is controlled by a signal supplied to wiring TX and has the function of controlling the timing at which the potential of the above node changes according to the current flowing through the photodetector (PD) 560. Transistor M13 functions as an amplifying transistor that provides an output according to the potential of the above node. Transistor M14 is controlled by a signal supplied to wiring SE and functions as a selection transistor for reading the output according to the potential of the above node with an external circuit connected to wiring OUT1.

[0277] Note that in Figures 10(A) and 10(B), the transistors are shown as n-channel transistors, but p-channel transistors can also be used.

[0278] It is preferable that the transistors in pixel circuit 530 and the transistors in pixel circuit 531 be formed side by side on the same substrate. In particular, it is preferable to configure the transistors in pixel circuit 530 and the transistors in pixel circuit 531 to be mixed within a single region and arranged periodically.

[0279] Furthermore, it is preferable to provide one or more layers having either or both transistors and / or capacitive elements in a position that overlaps with the light-receiving device (PD) 560 or the light-emitting device (EL) 550. This reduces the effective area occupied by each pixel circuit, enabling the realization of a high-definition light-receiving or display unit.

[0280] Next, Figure 10(C) shows an example of a specific transistor structure that can be applied to the pixel circuit described in Figures 10(A) and 10(B). Note that bottom-gate transistors or top-gate transistors can be used as appropriate.

[0281] The transistor shown in Figure 10(C) has 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 an insulating film 501C. The transistor also has an insulating film 516 (insulating film 516A and insulating film 516B) and an insulating film 518.

[0282] The semiconductor film 508 has a region 508A that is electrically connected to the conductive film 512A, and a region 508B that is electrically connected to the conductive film 512B. The semiconductor film 508 has a region 508C between regions 508A and 508B.

[0283] The conductive film 504 has a region that overlaps with region 508C, and the conductive film 504 has the function of a gate electrode.

[0284] The insulating film 506 has a region sandwiched between the semiconductor film 508 and the conductive film 504. The insulating film 506 functions as a first gate insulating film.

[0285] The conductive film 512A has either the function of a source electrode or the function of a drain electrode, and the conductive film 512B has either the function of a source electrode or the function of a drain electrode.

[0286] Furthermore, the conductive film 524 can be used in a transistor. The conductive film 524 has a region in which the semiconductor film 508 is sandwiched between it and the conductive film 504. The conductive film 524 functions as a second gate electrode. The insulating film 501D is sandwiched between the semiconductor film 508 and the conductive film 524 and functions as a second gate insulating film.

[0287] The insulating film 516 functions, for example, as a protective film covering the semiconductor film 508. Specifically, the insulating film 516 can include films containing silicon oxide, silicon oxide nitride, silicon nitride, silicon nitride, aluminum oxide, hafnium oxide, yttrium oxide, zirconium oxide, gallium oxide, tantalum oxide, magnesium oxide, lanthanum oxide, cerium oxide, or neodymium oxide.

[0288] The insulating film 518 is preferably made of a material that has the function of suppressing the diffusion of, for example, oxygen, hydrogen, water, alkali metals, alkaline earth metals, etc. Specifically, as the insulating film 518, for example, silicon nitride, silicon oxynitride, aluminum nitride, aluminum oxynitride, etc. are available. Furthermore, it is preferable that the number of nitrogen atoms is greater than the number of oxygen atoms in silicon oxynitride and aluminum oxynitride, respectively.

[0289] Furthermore, in the process of forming the semiconductor film used for the transistors in the pixel circuit, the semiconductor film used for the transistors in the drive circuit can also be formed. For example, a semiconductor film with the same composition as the semiconductor film used for the transistors in the pixel circuit can be used in the drive circuit.

[0290] Furthermore, the semiconductor film 508 preferably comprises, for example, indium, M (where M is one or more selected from gallium, aluminum, silicon, boron, yttrium, tin, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium), and zinc. In particular, it is preferable that M is one or more selected from aluminum, gallium, yttrium, and tin.

[0291] In particular, it is preferable to use an oxide containing indium (In), gallium (Ga), and zinc (Zn) (also written as IGZO) as the semiconductor film 508. Alternatively, it is preferable to use an oxide containing indium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium, gallium, tin, and zinc. Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), and zinc (Zn) (also written as IAZO). Alternatively, it is preferable to use an oxide containing indium (In), aluminum (Al), gallium (Ga), and zinc (Zn) (also written as IAGZO).

[0292] When the semiconductor film is an In-M-Zn oxide, it is preferable that the atomic ratio of In in the In-M-Zn oxide is greater than or equal to the atomic ratio of M. Possible atomic ratios of metal elements in such an In-M-Zn oxide include: In:M:Zn=1:1:1 or near that composition, In:M:Zn=1:1:1.2 or near that composition, In:M:Zn=1:3:2 or near that composition, In:M:Zn=1:3:4 or near that composition, In:M:Zn=2:1:3 or near that composition, In:M:Zn=3:1:2 or near that composition, and In:M:Zn=4:2:3 Examples include compositions near the desired atomic ratio, such as In:M:Zn=4:2:4.1 or near that ratio, In:M:Zn=5:1:3 or near that ratio, In:M:Zn=5:1:6 or near that ratio, In:M:Zn=5:1:7 or near that ratio, In:M:Zn=5:1:8 or near that ratio, In:M:Zn=6:1:6 or near that ratio, In:M:Zn=5:2:5 or near that ratio, etc. Note that "nearby composition" includes a range of ±30% of the desired atomic ratio.

[0293] For example, when describing a composition with an atomic ratio of In:Ga:Zn = 4:2:3 or a similar ratio, it includes cases where, when the atomic ratio of In is 4, the atomic ratio of Ga is between 1 and 3, and the atomic ratio of Zn is between 2 and 4. Also, when describing a composition with an atomic ratio of In:Ga:Zn = 5:1:6 or a similar ratio, it includes cases where, when the atomic ratio of In is 5, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is between 5 and 7. Furthermore, when describing a composition with an atomic ratio of In:Ga:Zn = 1:1:1 or a similar ratio, it includes cases where, when the atomic ratio of In is 1, the atomic ratio of Ga is greater than 0.1 and 2 or less, and the atomic ratio of Zn is greater than 0.1 and 2 or less.

[0294] The crystallinity of the semiconductor material used in the transistor is not particularly limited; amorphous semiconductors, crystalline semiconductors (microcrystalline semiconductors, polycrystalline semiconductors, single-crystal semiconductors, or semiconductors with crystalline regions in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0295] Furthermore, it is preferable that the semiconductor layer of the transistor has a metal oxide (also called an oxide semiconductor). Examples of crystalline oxide semiconductors include CAAC (c-axis-aligned crystalline)-OS and nc (nanocrystalline)-OS.

[0296] Alternatively, a transistor using silicon as the channel-forming region (Si transistor) may be used. Examples of silicon include single-crystal silicon (single-crystal Si), polycrystalline silicon, and amorphous silicon. In particular, a transistor having low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) in the semiconductor layer (hereinafter also referred to as an LTPS transistor) can be used. LTPS transistors have high field-effect mobility and good frequency characteristics.

[0297] By using Si transistors such as LTPS transistors, circuits that need to be driven at high frequencies (e.g., source driver circuits) can be fabricated on the same board as the display unit. This simplifies the external circuits mounted on the light-emitting device, reducing component and mounting costs.

[0298] OS transistors have extremely high field-effect mobility compared to transistors using amorphous silicon. Furthermore, OS transistors exhibit remarkably low source-drain leakage current (hereinafter also referred to as off-current) in the off state, allowing them to retain charge stored in a capacitor connected in series with the transistor for extended periods. Additionally, the application of OS transistors can reduce the power consumption of light-emitting devices.

[0299] Furthermore, the off-current value of an OS transistor per 1 μm channel width at room temperature is 1 aA (1 × 10⁻¹⁰). -18 A) Below, 1zA(1×10 -21 A) Less than or equal to 1yA(1×10 -24A) It can be less than or equal to the following. Note that the off-current value of a Si transistor per 1 μm of channel width at room temperature is 1 fA (1 × 10⁻¹⁰). -15 A) More than 1pA (1×10 -12 A) The answer is as follows. Therefore, it can be said that the off-current of an OS transistor is about 10 orders of magnitude lower than that of a Si transistor.

[0300] Furthermore, to increase the luminescence brightness of the light-emitting device included in the pixel circuit, it is necessary to increase the amount of current flowing through the light-emitting device. To achieve this, it is necessary to increase the source-drain voltage of the drive transistor included in the pixel circuit. Compared to Si transistors, OS transistors have a higher breakdown voltage between the source and drain, so a higher voltage can be applied between the source and drain of an OS transistor. Therefore, by using an OS transistor as the drive transistor included in the pixel circuit, the amount of current flowing through the light-emitting device can be increased, thereby increasing the luminescence brightness of the light-emitting device.

[0301] Furthermore, when the transistor operates in the saturation region, OS transistors exhibit smaller changes in source-drain current in response to changes in gate-source voltage compared to Si transistors. Therefore, by using OS transistors as driving transistors in the pixel circuit, the current flowing between the source and drain can be precisely controlled by changes in gate-source voltage, thereby controlling the amount of current flowing to the light-emitting device. This allows for a wider range of tonal gradations in the pixel circuit.

[0302] Furthermore, in terms of the saturation characteristics of the current flowing when a transistor operates in the saturation region, OS transistors can supply a more stable current (saturation current) than Si transistors, even when the source-drain voltage gradually increases. Therefore, by using OS transistors as driving transistors, a stable current can be supplied to the light-emitting device even if there are variations in the current-voltage characteristics of the EL device. In other words, when operating in the saturation region, the source-drain current remains almost unchanged even when the source-drain voltage is increased, thus stabilizing the luminescence brightness of the light-emitting device.

[0303] As described above, by using OS transistors in the drive transistors included in the pixel circuit, it is possible to achieve "suppression of black level floating," "increase in luminescence brightness," "multi-gradation," and "suppression of variations in light-emitting devices."

[0304] Alternatively, the semiconductor film used for the transistors in the drive circuit can be formed using the same process as the semiconductor film used for the transistors in the pixel circuit. Alternatively, the drive 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.

[0305] Furthermore, silicon may be used for the semiconductor film 508. Examples of silicon include single-crystal silicon, polycrystalline silicon, and amorphous silicon. In particular, it is preferable to use a transistor having low-temperature polysilicon (LTPS (Low Temperature Poly Silicon)) in the semiconductor layer (hereinafter also referred to as an LTPS transistor). LTPS transistors have high field-effect mobility and good frequency characteristics.

[0306] By using silicon-based transistors such as LTPS transistors, circuits that need to be driven at high frequencies (e.g., source driver circuits) can be fabricated on the same circuit board as the display unit. This simplifies the external circuits implemented in the light-emitting device, reducing component and mounting costs.

[0307] Furthermore, it is preferable to use a transistor (hereinafter also called an OS transistor) in which a metal oxide (hereinafter also called an oxide semiconductor) is used as the semiconductor in which the channel is formed. Compared to transistors using amorphous silicon, OS transistors have extremely high field-effect mobility. In addition, OS transistors have a remarkably small source-drain leakage current (hereinafter also called an off-current) in the off state, and can retain the charge stored in a capacitor connected in series with the transistor for a long period of time. Moreover, by applying OS transistors, the power consumption of the light-emitting device can be reduced.

[0308] By using LTPS transistors in some of the transistors included in the pixel circuit and OS transistors in others, it is possible to realize a light-emitting device with low power consumption and high driving capability. A more preferable example is to apply OS transistors to transistors that function as switches to control conduction and non-conduction between wiring, and LTPS transistors to transistors that control current. A configuration that combines both LTPS transistors and OS transistors is sometimes referred to as LTPO. By using LTPO, it is possible to realize a display panel with low power consumption and high driving capability.

[0309] For example, one of the transistors provided in the pixel circuit functions as a transistor for controlling the current flowing to the light-emitting device, and can also be called a drive transistor. One of the source and drain of the drive transistor is electrically connected to the pixel electrode of the light-emitting device. It is preferable to use an LTPS transistor for this drive transistor. This makes it possible to increase the current flowing to the light-emitting device in the pixel circuit.

[0310] On the other hand, another transistor provided in the pixel circuit functions as a switch to control the selection and deselection of pixels, and can also be called a selection transistor. The gate of the selection transistor is electrically connected to the gate line, and one of the source and drain is electrically connected to the source line (signal line). It is preferable to use an OS transistor for the selection transistor. This makes it possible to maintain the gradation of pixels even when the frame frequency is significantly reduced (e.g., 1 fps or less), and thus power consumption can be reduced by stopping the driver when displaying still images.

[0311] When an oxide semiconductor is used as the semiconductor film, the device 720 has a configuration in which an oxide semiconductor is used as the semiconductor film and a light-emitting device with an MML (metal maskless) structure. This configuration makes it possible to make the leakage current that can flow through the transistor and the leakage current that can flow between adjacent light-emitting elements (also called lateral leakage current or side leakage current) extremely low. Furthermore, with the above configuration, when an image is displayed on the display device, the observer can observe one or more of the following: image sharpness, image clarity, high saturation, and high contrast ratio. Moreover, by making the leakage current that can flow through the transistor and the lateral leakage current between light-emitting elements extremely low, it is possible to achieve a display (also called true black display) with as little light leakage (so-called black floating) that may occur when displaying black as possible.

[0312] In particular, among light-emitting devices with an MML structure, applying the SBS structure described above results in a configuration where the layer provided between light-emitting elements (for example, an organic layer used in common between light-emitting elements, also called a common layer) is separated, making it possible to achieve a display with no side leakage or extremely low side leakage.

[0313] Furthermore, the transistor configuration used in the display panel can be appropriately selected according to the screen size of the display panel. For example, when single-crystal Si transistors are used as the transistors in the display panel, it can be applied to screen sizes with a diagonal size of 0.1 inches to 3 inches. When LTPS transistors are used as the transistors in the display panel, it can be applied to screen sizes with a diagonal size of 0.1 inches to 30 inches, preferably 1 inch to 30 inches. When LTPO (a configuration combining LTPS transistors and OS transistors) is used in the display panel, it can be applied to screen sizes with a diagonal size of 0.1 inches to 50 inches, preferably 1 inch to 50 inches. When OS transistors are used as the transistors in the display panel, it can be applied to screen sizes with a diagonal size of 0.1 inches to 200 inches, preferably 50 inches to 100 inches.

[0314] Furthermore, single-crystal Si transistors are extremely difficult to enlarge due to the size of the single-crystal Si substrate. Similarly, LTPS transistors require laser crystallization during the manufacturing process, making it difficult to accommodate larger screen sizes (typically exceeding 30 inches diagonally). On the other hand, OS transistors are not subject to the constraints of using laser crystallization during the manufacturing process, or can be manufactured at relatively low process temperatures (typically below 450°C), making them suitable for relatively large display panels (typically between 50 and 100 inches diagonally). LTPO transistors can be applied to display panel sizes in the range between those using LTPS and OS transistors (typically between 1 and 50 inches diagonally).

[0315] Next, Figures 11(A) and 11(B) show cross-sectional views of the apparatus.

[0316] Figures 11(A) and 11(B) show cross-sectional views when the device shown in Figure 9(A) is a light-emitting device. Specifically, they show cross-sectional views when a portion of the area including the FPC 713 and wiring 706 is cut, and a portion of the display area 701 including pixels 703(i,j) is cut. Figure 11(A) shows a light-emitting device with a structure that extracts light from the top of the drawing (towards the second substrate 770) (top emission type), and Figure 11(B) shows a light-emitting device with a structure that extracts light from the bottom of the drawing (towards the first substrate 510) (bottom emission type).

[0317] In Figure 11(A), the device (light-emitting device) 700 has a functional layer 520 between the first substrate 510 and the second substrate 770. The functional layer 520 includes the transistors (M15, M16, M17) and capacitive elements (C3) mentioned above, as well as wiring (VS, VG, V4, V5) that electrically connects them. In Figure 11(A), the functional layer 520 is shown to include a pixel circuit 530B(i,j) and a pixel circuit 530G(i,j) and a drive circuit GD, but is not limited to this configuration.

[0318] Furthermore, each pixel circuit of the functional layer 520 (for example, pixel circuits 530B(i,j) and 530G(i,j) shown in Figure 11(A)) is electrically connected to each light-emitting device formed on the functional layer 520 (for example, light-emitting devices 550B(i,j) and 550G(i,j) shown in Figure 11(A)). Specifically, light-emitting device 550B(i,j) is electrically connected to pixel circuit 530B(i,j) via wiring 591B, and light-emitting device 550G(i,j) is electrically connected to pixel circuit 530G(i,j) via wiring 591G. In addition, 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 bonding the second substrate 770 and the functional layer 520.

[0319] Furthermore, the second substrate 770 can be a substrate equipped with touch sensors in a matrix. For example, a substrate equipped with a capacitive touch sensor or an optical touch sensor can be used as the second substrate 770. This allows the light-emitting device according to one embodiment of the present invention to be used as a touch panel.

[0320] Furthermore, although Figures 11(A) and 11(B) describe an active matrix type light-emitting device, the configuration of the light-emitting device shown in Embodiment 1 and Embodiment 2 may also be applied to a passive matrix type light-emitting device.

[0321] (Embodiment 5) In this embodiment, the configuration of an electronic device according to one aspect of the present invention will be explained with reference to Figures 12(A) to 14(B).

[0322] Figures 12(A) to 14(B) illustrate the configuration of an electronic device according to one embodiment of the present invention. Figure 12(A) is a block diagram of the electronic device, and Figures 12(B) to 12(E) are perspective views illustrating the configuration of the electronic device. Figures 13(A) to 13(E) are perspective views illustrating the configuration of the electronic device, and Figures 14(A) and 14(B) are perspective views illustrating the configuration of the electronic device.

[0323] The electronic device 5200B described in this embodiment includes a computing device 5210 and an input / output device 5220 (see Figure 12(A)).

[0324] The arithmetic unit 5210 has a function to receive operation information and a function to supply image information based on the operation information.

[0325] The input / output device 5220 includes a display unit 5230, an input unit 5240, a detection unit 5250, a communication unit 5290, a function for supplying operation information, and a function for supplying image information. Furthermore, the input / output device 5220 also includes a function for supplying detection information, a function for supplying communication information, and a function for receiving communication information.

[0326] The input unit 5240 has the function of supplying operation information. For example, the input unit 5240 supplies operation information based on the operation of the user of the electronic device 5200B.

[0327] Specifically, the input unit 5240 can use a keyboard, hardware buttons, pointing device, touch sensor, illuminance sensor, imaging device, voice input device, eye-tracking device, posture detection device, etc.

[0328] The display unit 5230 has the function of displaying a display panel and image information. For example, the display panel described in Embodiment 3 can be used in the display unit 5230.

[0329] The detection unit 5250 has the function of supplying detection information. For example, it has the function of detecting the surrounding environment in which electronic equipment is being used and supplying it as detection information.

[0330] Specifically, illuminance sensors, imaging devices, posture detection devices, pressure sensors, and human presence sensors can be used in the detection unit 5250.

[0331] The communication unit 5290 has functions for receiving and supplying communication information. For example, it has functions for connecting with other electronic devices or communication networks via wireless or wired communication. Specifically, it has functions such as wireless local area communication, telephone communication, and short-range wireless communication.

[0332] Figure 12(B) shows an electronic device having an external shape that follows a cylindrical column or the like. One example is digital signage. A display panel, which is one aspect of the present invention, can be applied to the display unit 5230. It may also have a function to change the display method according to the illumination of the usage environment. It may also have a function to change the display content when a person is detected. This allows it to be installed, for example, on a building column, or to display advertisements or information.

[0333] Figure 12(C) shows an electronic device that has the function of generating image information based on the trajectory of a pointer used by the user. Examples include electronic whiteboards, electronic bulletin boards, and electronic signboards. 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.

[0334] Figure 12(D) shows an electronic device that can receive information from other devices and display it on the display unit 5230. One example is a wearable electronic device. Specifically, it can display several options, or the user can select several options and send them back to the information sender. Alternatively, it can have a function to change the display method according to the illumination of the usage environment. This can reduce the power consumption of the wearable electronic device, for example. Alternatively, it can display images on the wearable electronic device so that it can be used suitably even in environments with strong ambient light, such as outdoors on a sunny day.

[0335] Figure 12(E) shows an electronic device having a display unit 5230 with a curved surface that gently curves along the side of the housing. One example is a mobile phone. The display unit 5230 includes a display panel, which has the function of displaying on, for example, the front, side, top, and back. This allows information to be displayed not only on the front of the mobile phone, but also on the sides, top, and back.

[0336] Figure 13(A) shows an electronic device that can receive information from the internet and display it on the display unit 5230. One example is a smartphone. For example, a message that has been created can be viewed on the display unit 5230. Alternatively, a message that has been created can be sent to another device. Alternatively, for example, it has a function to change the display method according to the illumination of the usage environment. This can reduce the power consumption of the smartphone. Alternatively, for example, an image can be displayed on the smartphone so that it can be used suitably even in environments with strong ambient light, such as outdoors on a sunny day.

[0337] Figure 13(B) shows an electronic device that can use a remote controller as an input unit 5240. One example is a television system. For example, it can receive information from a broadcasting station or the internet and display it on the display unit 5230. Alternatively, it can photograph the user using the detection unit 5250. Alternatively, it can transmit the user's video. Alternatively, it can acquire the user's viewing history and provide it to a cloud service. Alternatively, it can acquire recommendation information from a cloud service and display it on the display unit 5230. Alternatively, it can display a program or video based on the recommendation information. Alternatively, for example, it has a function to change the display method according to the illumination of the usage environment. This makes it possible to display images on the television system so that it can be used effectively even when strong sunlight shines into the room on a sunny day.

[0338] Figure 13(C) shows an electronic device that can receive educational materials from the internet and display them on the display unit 5230. An example of such a device is a tablet computer. Using the input unit 5240, a report can be entered and sent to the internet. Alternatively, the correction results or evaluations of the report can be obtained from a cloud service and displayed on the display unit 5230. Or, based on the evaluation, suitable educational materials can be selected and displayed.

[0339] For example, the display unit 5230 can receive image signals from other electronic devices and display them. Alternatively, it can be propped up on a stand or the like and used as a sub-display. This allows images to be displayed on the tablet computer in a way that is suitable for use even in environments with strong ambient light, such as outdoors on a sunny day.

[0340] Figure 13(D) shows an electronic device having multiple display units 5230. One example is a digital camera. For example, the display unit 5230 can display an image while the detection unit 5250 is capturing it. Alternatively, the captured image can be displayed on the detection unit. Alternatively, the captured image can be decorated using the input unit 5240. Alternatively, a message can be attached to the captured image. Alternatively, it can be transmitted to the internet. Alternatively, it has a function to change the shooting conditions according to the illumination of the usage environment. This makes it possible to display the subject on the digital camera so that it can be viewed favorably even in environments with strong ambient light, such as outdoors on a sunny day.

[0341] Figure 13(E) shows an electronic device that can control other electronic devices by using the electronic device of this embodiment as a master and using other electronic devices as slaves. One example is a portable personal computer. For example, part of the image information can be displayed on the display unit 5230 and the other part of the image information can be displayed on the display unit of the other electronic device. Alternatively, an image signal can be supplied. Alternatively, information to be written can be obtained from the input unit of the other electronic device using the communication unit 5290. This allows, for example, a portable personal computer to utilize a wide display area.

[0342] Figure 14(A) shows an electronic device having a detection unit 5250 that detects acceleration or direction. An example is a goggle-type electronic device. The detection unit 5250 can supply information relating to the user's position or the direction the user is facing. Alternatively, the electronic device can generate image information for the right eye and image information for the left eye based on the user's position or the direction the user is facing. Alternatively, the display unit 5230 has a display area for the right eye and a display area for the left eye. This allows, for example, the display of an immersive virtual reality space on a goggle-type electronic device.

[0343] Figure 14(B) shows an electronic device having an imaging device and a detection unit 5250 that detects acceleration or direction. An example is a glasses-type electronic device. The detection unit 5250 can supply information relating to the user's position or the direction the user is facing. Alternatively, the electronic device can generate image information based on the user's position or the direction the user is facing. This allows, for example, information to be attached to and displayed on a real-world landscape. Alternatively, images of an augmented reality space can be displayed on the glasses-type electronic device.

[0344] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0345] (Embodiment 6) In this embodiment, a configuration in which the light-emitting devices described in Embodiment 1 and Embodiment 2 are used as an illumination device will be explained with reference to Figure 15. Figure 15(A) is a cross-sectional view of the line segment ef in the top view of the illumination device shown in Figure 15(B).

[0346] In this embodiment, the lighting device has a first electrode 401 formed on a translucent substrate 400 which serves as a support. The first electrode 401 corresponds to the first electrode 101 in Embodiments 1 and 2. When light is extracted from the first electrode 401 side, the first electrode 401 is formed from a translucent material.

[0347] A pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0348] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the configuration of the EL layer 103 in Embodiment 1 and Embodiment 2. Please refer to the respective descriptions for details on these configurations.

[0349] 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 and Embodiment 2. When light emission is extracted from the first electrode 401 side, the second electrode 404 is formed of a material with high reflectivity. Voltage is supplied to the second electrode 404 by connecting it to the pad 412.

[0350] As described above, the lighting device shown in this embodiment has a light-emitting device having a first electrode 401, an EL layer 403, and a second electrode 404. Since this light-emitting device is a light-emitting device with high luminous efficiency, the lighting device in this embodiment can be a lighting device with low power consumption.

[0351] The lighting device is completed by fixing and sealing the substrate 400, on which the light-emitting device having the above configuration is formed, and the sealing substrate 407 using sealing materials (405, 406). Either sealing material 405 or 406 may be used. In addition, a desiccant can be mixed into the inner sealing material 406 (not shown in Figure 15(B)), which allows for the adsorption of moisture and leads to improved reliability.

[0352] Furthermore, by extending the pad 412 and a portion of the first electrode 401 outside the sealing materials 405 and 406, it can be used as an external input terminal. Alternatively, an IC chip 420 with a converter or the like may be placed on top of it.

[0353] (Embodiment 7) In this embodiment, an example of an application of a lighting device manufactured by applying a light-emitting device, or a light-emitting device which is a part thereof, which is one aspect of the present invention, will be explained with reference to Figure 16.

[0354] For indoor lighting, it can be used as a ceiling light 8001. The ceiling light 8001 is available in both surface-mounted and recessed ceiling types. Such lighting devices are constructed by combining a light-emitting device with a housing and cover. It can also be used as a cord pendant type (suspended from the ceiling by a cord).

[0355] Furthermore, the 8002 footlight illuminates the floor surface, enhancing safety underfoot. For example, it is effective for use in bedrooms, stairwells, and corridors. In such cases, the size and shape can be appropriately changed according to the size and structure of the room. It can also be configured as a freestanding lighting device consisting of a light-emitting device and a support base.

[0356] Furthermore, the sheet-type lighting 8003 is a thin, sheet-shaped lighting device. Because it is attached to a wall surface, it does not take up much space and can be used in a wide range of applications. It can also be easily made to cover a large area. It can also be used on curved walls or enclosures.

[0357] Alternatively, a lighting device 8004 can be used in which the light from the light source is controlled to flow only in a desired direction.

[0358] Furthermore, the desk lamp 8005 has a light source 8006, and as the light source 8006, a light-emitting device that is a part of the present invention or a light-emitting device that is a part thereof can be applied.

[0359] In addition to the above, by applying a light-emitting device, or a light-emitting device that is a part thereof, according to one aspect of the present invention, to a part of the furniture installed in the room, it is possible to create a lighting device that also functions as furniture.

[0360] As described above, various lighting devices can be obtained by applying a light-emitting device. These lighting devices are included in one aspect of the present invention.

[0361] Furthermore, the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments.

[0362] (Embodiment 8) In this embodiment, a light-emitting device and a light-receiving device applicable to a display device according to one aspect of the present invention will be described with reference to Figure 17.

[0363] Figure 17(A) shows a schematic cross-sectional view of the light-emitting device 805a and the light-receiving device 805b of a display device 810 according to one aspect of the present invention.

[0364] The light-emitting device 805a has a function of emitting light (hereinafter also referred to as the light-emitting function). The light-emitting device 805a has an electrode 801a, an EL layer 803a, and an electrode 802. Preferably, the light-emitting device 805a is a light-emitting device (organic EL device) that utilizes organic EL as shown in Embodiment 1 and Embodiment 2. Therefore, the EL layer 803a sandwiched between the electrode 801a and the electrode 802 has at least a light-emitting layer. The light-emitting layer has a light-emitting material. By applying a voltage between the electrode 801a and the electrode 802, light is emitted from the EL layer 803a. In addition to the light-emitting layer, the EL layer 803a may have various layers such as a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a carrier (hole or electron) blocking layer, and a charge generation layer.

[0365] The light-receiving device 805b has a function to detect light (hereinafter also referred to as the light-receiving function). For example, the light-receiving device 805b can be a pn-type or pin-type photodiode. The light-receiving device 805b has an electrode 801b, a light-receiving layer 803b, and an electrode 802. The light-receiving layer 803b, sandwiched between electrodes 801b and 802, has at least an active layer. The light-receiving layer 803b can also be made of the same materials used for various layers of the EL layer 803a described above (hole injection layer, hole transport layer, light-emitting layer, electron transport layer, electron injection layer, carrier (hole or electron) blocking layer, charge generation layer, etc.). The light-receiving device 805b functions as a photoelectric conversion device and can generate charge from light incident on the light-receiving layer 803b, which can then be extracted as an electric current. At this time, a voltage may be applied between electrodes 801b and 802. The amount of charge generated is determined based on the amount of light incident on the light-receiving layer 803b.

[0366] The light-receiving device 805b has the function of detecting visible light. The light-receiving device 805b is sensitive to visible light. It is even more preferable that the light-receiving device 805b has the function of detecting both visible light and infrared light. It is preferable that the light-receiving device 805b is sensitive to both visible light and infrared light.

[0367] In this specification, the wavelength range for blue (B) is defined as 400 nm to less than 490 nm, and blue (B) light is defined as having at least one emission spectral peak in this wavelength range. The wavelength range for green (G) is defined as 490 nm to less than 580 nm, and green (G) light is defined as having at least one emission spectral peak in this wavelength range. The wavelength range for red (R) is defined as 580 nm to less than 700 nm, and red (R) light is defined as having at least one emission spectral peak in this wavelength range. In this specification, the wavelength range for visible light is defined as 400 nm to less than 700 nm, and visible light is defined as having at least one emission spectral peak in this wavelength range. The wavelength range for infrared (IR) is defined as 700 nm to less than 900 nm, and infrared (IR) light is defined as having at least one emission spectral peak in this wavelength range.

[0368] The active layer of the light-receiving device 805b includes a semiconductor. Examples of such semiconductors include inorganic semiconductors such as silicon, and organic semiconductors containing organic compounds. It is preferable to use an organic semiconductor device (or organic photodiode) as the light-receiving device 805b, which includes an organic semiconductor in its active layer. Organic photodiodes are easily made thinner, lighter, and larger in area, and offer greater freedom in shape and design, making them applicable to various display devices. Furthermore, using an organic semiconductor allows the EL layer 803a of the light-emitting device 805a and the light-receiving layer 803b of the light-receiving device 805b to be formed using the same method (e.g., vacuum deposition), and common manufacturing equipment can be used, which is preferable. Note that an organic compound, according to one aspect of the present invention, can be used for the light-receiving layer 803b of the light-receiving device 805b.

[0369] In one aspect of the present invention, a display device preferably uses an organic EL device as the light-emitting device 805a and an organic photodiode as the light-receiving device 805b. The organic EL device and the organic photodiode can be formed on the same substrate. Therefore, an organic photodiode can be incorporated into a display device using an organic EL device. In addition to the function of displaying images, the display device according to one aspect of the present invention also has one or both of the functions of imaging and sensing.

[0370] Electrodes 801a and 801b are provided on the same plane. Figure 17(A) shows a configuration in which electrodes 801a and 801b are provided on the substrate 800. Electrodes 801a and 801b can be formed, for example, by processing a conductive film formed on the substrate 800 into island shapes. In other words, electrodes 801a and 801b can be formed through the same process.

[0371] The substrate 800 can be a heat-resistant substrate capable of withstanding the formation of the light-emitting device 805a and the light-receiving device 805b. When an insulating substrate is used as the substrate 800, glass substrates, quartz substrates, sapphire substrates, ceramic substrates, organic resin substrates, etc., can be used. In addition, semiconductor substrates such as single-crystal semiconductor substrates made of silicon or silicon carbide, polycrystalline semiconductor substrates, compound semiconductor substrates such as silicon germanium, and SOI substrates can be used.

[0372] In particular, it is preferable to use a substrate 800 on which a semiconductor circuit including semiconductor elements such as transistors is formed on the aforementioned insulating substrate or semiconductor substrate. It is preferable that the semiconductor circuit constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), etc. In addition to the above, an arithmetic circuit, a memory circuit, etc. may also be configured.

[0373] Furthermore, electrode 802 is an electrode made of a layer common to both the light-emitting device 805a and the light-receiving device 805b. Of these electrodes, the electrode that emits light or receives light as an incident electrode preferably uses a conductive film that transmits visible light and infrared light. The electrode that does not emit light or receives light as an incident electrode preferably uses a conductive film that reflects visible light and infrared light.

[0374] In one embodiment of the present invention, the electrode 802 in the display device functions as one of the electrodes of the light-emitting device 805a and the light-receiving device 805b.

[0375] Figure 17(B) shows the case where electrode 801a of the light-emitting device 805a has a higher potential than electrode 802. In this case, electrode 801a functions as the anode of the light-emitting device 805a, and electrode 802 functions as the cathode. Also, electrode 801b of the light-receiving device 805b has a lower potential than electrode 802. In Figure 17(B), to make the direction of current flow clearer, the circuit symbol for the light-emitting diode is shown to the left of the light-emitting device 805a, and the circuit symbol for the photodiode is shown to the right of the light-receiving device 805b. Furthermore, the direction of carrier (electron and hole) flow is schematically indicated by arrows within each device.

[0376] In the configuration shown in Figure 17(B), when a first potential is supplied to electrode 801a via the first wiring, a second potential is supplied to electrode 802 via the second wiring, and a third potential is supplied to electrode 801a via the third wiring in the light-emitting device 805a, the relationship between the magnitudes of each potential is first potential > second potential > third potential.

[0377] Figure 17(C) also shows the case where electrode 801a of the light-emitting device 805a has a lower potential than electrode 802. In this case, electrode 801a functions as the cathode of the light-emitting device 805a, and electrode 802 functions as the anode. Also, electrode 801b of the light-receiving device 805b has a lower potential than electrode 802 and a higher potential than electrode 801a. In Figure 17(C), to make the direction of current flow clearer, the circuit symbol for the light-emitting diode is shown to the left of the light-emitting device 805a, and the circuit symbol for the photodiode is shown to the right of the light-receiving device 805b. Furthermore, the direction of carrier (electron and hole) flow is schematically indicated by arrows within each device.

[0378] In the configuration shown in Figure 17(C), when a first potential is supplied to electrode 801a via the first wiring in the light-emitting device 805a, a second potential is supplied to electrode 802 via the second wiring, and a third potential is supplied to electrode 801a via the third wiring, the relationship between the magnitudes of each potential is second potential > third potential > first potential.

[0379] In this embodiment, the resolution of the light-receiving device 805b is 100 ppi or more, preferably 200 ppi or more, more preferably 300 ppi or more, more preferably 400 ppi or more, and even more preferably 500 ppi or more, and can be 2000 ppi or less, 1000 ppi or less, or 600 ppi or less. In particular, by arranging the light-receiving device 805b with a resolution of 200 ppi or more and 600 ppi or less, preferably 300 ppi or more and 600 ppi or less, it can be suitably used for fingerprint imaging. When performing fingerprint authentication using a display device according to one aspect of the present invention, increasing the resolution of the light-receiving device 805b allows for the extraction of fingerprint feature points (Minutia) with high accuracy, for example, thereby improving the accuracy of fingerprint authentication. Furthermore, a resolution of 500 ppi or more is preferable because it allows compliance with standards such as those of the National Institute of Standards and Technology (NIST). Assuming the resolution of the light-receiving device is 500 ppi, each pixel would be 50.8 μm in size, which is sufficient resolution to capture the width of a fingerprint (typically between 300 μm and 500 μm).

[0380] Furthermore, the configuration shown in this embodiment can be used in appropriate combination with the configurations shown in other embodiments. [Examples]

[0381] In this example, four types of materials were used to create thin films by depositing one or two of the materials onto a glass substrate. Samples with different film structures (single-layer films, multilayer films, mixed films, etc.) were prepared, and heat resistance tests were performed on each sample. The thermal properties of the materials used in this example are shown in Table 1, and their structural formulas are shown below. For differential scanning calorimetry (DSC measurement), the thermal properties were measured using a PerkinElmer Pyris1DSC. In this specification, the results shown in Table 1 (Ttc) are referred to as the crystallization temperature (Ttc) in the thin film state.

[0382] [Table 1]

[0383] [ka]

[0384] Next, the methods for preparing the samples (Sample 1 to Sample 7) are shown.

[0385] First, a sample layer was formed on a glass substrate using a vacuum deposition apparatus, and the sample was obtained by cutting it into a 2cm x 2cm square shape. Next, the sample was introduced into a bell jar type heater (Shibata Scientific Co., Ltd. Bell Jar Type Vacuum Oven BV-001), the pressure was reduced to about 10 hPa, and then it was fired for 1 hour at a set temperature in the range of 80°C to 190°C. After 1 hour, the substrate was cooled to 40°C, and after being released into the atmosphere, the sample was removed with tweezers.

[0386] The sample layer of Sample 1 is a monolayer film using one type of heteroaromatic compound. It was formed by depositing 2,9-di(2-naphthyl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBPhen) onto a glass substrate to a thickness of 10 nm.

[0387] The sample layer of Sample 2 is a monolayer film using one type of heteroaromatic compound. It was formed by depositing 2-[4'-(9-phenyl-9H-carbazole-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviated as 2mpPCBPDBq) onto a glass substrate to a thickness of 10 nm.

[0388] The sample layer of Sample 3 is a monolayer film using one type of heteroaromatic compound. It was formed by depositing 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofl[3,2-d]pyrimidine (abbreviated as 8BP-4mDBtPBfpm) onto a glass substrate to a thickness of 10 nm.

[0389] The sample layer of Sample 4 is a monolayer film using one type of heteroaromatic compound. It was formed by depositing 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as 6,6'(P-Bqn)2BPy) onto a glass substrate to a thickness of 10 nm.

[0390] The sample layer of Sample 5 is a multilayer film using multiple heteroaromatic compounds. It was formed by depositing 2mpPCBPDBq at a depth of 10 nm on a glass substrate, followed by depositing NBPhen at a depth of 10 nm.

[0391] The sample layer of Sample 6 is a multilayer film using multiple heteroaromatic compounds. It was formed by depositing 8BP-4mDBtPBfpm at a depth of 10 nm on a glass substrate, followed by depositing 6,6'(P-Bqn)2BPy at a depth of 10 nm.

[0392] The sample layer of Sample 7 is a multilayer film using multiple heteroaromatic compounds. It was formed by depositing 10 nm of 8BP-4mDBtPBfpm onto a glass substrate, followed by depositing 10 nm of NBPhen.

[0393] Each sample prepared using this method was observed visually and with an optical microscope (Olympus Corporation Semiconductor / FPD Inspection Microscope MX61L).

[0394] Photographs of the samples prepared in this example (observed under dark-field conditions at 100x magnification) are shown in Figures 18 to 20.

[0395] The structure of each sample and the crystallization results based on Figures 18 to 20 are shown in Table 2 below. In Table 2, ○ indicates that no crystals were formed (no crystallization), △ indicates that some crystallization occurred (some crystallization present), and × indicates that crystals were formed (crystallization present). Specifically, a △ is judged when a white line is visible only at the edge of the thin film, with an edge width of approximately 20 μm being judged as △, and anything wider as ×.

[0396] [Table 2]

[0397] From the above results, Sample 1:NBPhen, a single film of one type of heteroaromatic compound, does not crystallize up to high temperatures (crystallization begins around 140°C or 150°C), forming a thin film with relatively good heat resistance. However, in the case of Sample 5:2mpPCBPDBq\NBPhen, which is laminated with the material of Sample 2:2mpPCBPDBq, which has poor heat resistance, the heat resistance is significantly reduced. Similarly, in the case of Sample 7:8BP-4mDBtPBfpm\NBPhen, which is laminated with the material of Sample 1:NBPhen, which has good heat resistance, the heat resistance is also significantly reduced.

[0398] On the other hand, in the case of sample 6: 8BP-4mDBtPBfpm\6,6'(P-Bqn)2BPy, which was created by laminating the material of sample 3: 8BP-4mDBtPBfpm, which has good heat resistance, and the material of sample 4: 6,6'(P-Bqn)2BPy, which has relatively good heat resistance, good heat resistance was obtained.

[0399] Furthermore, the above results show that when examining the difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state, 8BP-4mDBtPBfpm used in Sample 3 has a temperature of approximately 0°C, NBPhen used in Sample 1 has a temperature of approximately 170°C, 2mpPCBPDBq used in Sample 2 has a temperature of approximately 20°C, and 6,6'(P-Bqn)2BPy used in Sample 4 has a temperature of approximately 50°C. This suggests that, not only for single films but also for multilayer films, if a material with a small temperature difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state (in this example, 8BP-4mDBtPBfpm used in Sample 3) is formed first, it is possible to form a film (multilayer film) that is less affected by heat.

[0400] In other words, materials with a small difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state (specifically, preferably 20°C or less) can maintain a thermally stable film surface because the thin film state is less affected by heat.

[0401] Here, Table 3 below shows the specific physical properties of Sample 5, Sample 6, and Sample 7, as shown in Table 2.

[0402] [Table 3]

[0403] From the results in Table 2, among the samples shown in Table 3, sample 6 is suitable for devices formed including a thermal process. Specifically, in comparison with samples 5 and 7, sample 6 preferably uses a material in which the difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state (|Tpc of powder - Ttc of thin film|) is 20°C or less for the first layer of the laminated film, and a material in which the |Tpc of powder - Ttc of thin film| is 100°C or less, more preferably 50°C or less for the second layer of the laminated film. When the first and second layers are used as electron transport layers in a light-emitting device, the first layer is formed in contact with the light-emitting layer, and the second layer is formed in contact with the first layer.

[0404] Therefore, by using a material that can maintain such a heat-stable film surface in a light-emitting device (preferably an EL layer, and more preferably a light-emitting layer, an electron transport layer, or an electron injection layer), it is possible to provide a highly heat-resistant light-emitting device or organic semiconductor device that is less affected by heat treatment during the manufacturing process. [Examples]

[0405] From the results of Example 1, it was found that heat resistance is improved by layering a first heteroaromatic compound, in which the temperature difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state is within 20°C, and a second heteroaromatic compound, in which the temperature difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state is within 100°C. Therefore, in this example, a light-emitting device was fabricated using these materials as an electron transport layer, and the relationship between heat resistance and device characteristics was confirmed.

[0406] In this embodiment, the light-emitting device is constructed such that the electron transport layer has a stacked structure, the first electron transport layer in contact with the light-emitting layer has a first heteroaromatic compound whose crystallization temperature (Tpc) in the powder state and crystallization temperature (Ttc) in the thin film state are within 20°C, and the second electron transport layer in contact with the first electron transport layer has a second heteroaromatic compound whose crystallization temperature (Tpc) in the powder state and crystallization temperature (Ttc) in the thin film state are within 100°C.

[0407] Specifically, a light-emitting device 1 having the above configuration and a comparative light-emitting device 3 not having the above configuration were fabricated, and the characteristics of each light-emitting device were compared. The device structure and its characteristics are described below. In this embodiment, after obtaining the device characteristics (voltage, current, brightness, chromaticity, EL spectrum) of light-emitting device 1, a device obtained by baking light-emitting device 1 on a hot plate set to 120°C for 1 hour was designated as light-emitting device 2. Similarly, after obtaining the device characteristics (voltage, current, brightness, chromaticity, EL spectrum) of comparative light-emitting device 3, a device obtained by baking comparative light-emitting device 3 on a hot plate set to 120°C for 1 hour was designated as comparative light-emitting device 4. The specific configurations of these light-emitting devices 1, 2, 3, and 4 are shown in Table 4. The chemical formulas of the materials used in this embodiment are shown below.

[0408] [Table 4]

[0409] [ka]

[0410] <Fabrication of each light-emitting device> As shown in Figure 21, each light-emitting device in this embodiment has a structure in which a hole injection layer 911, a hole transport layer 912, a light-emitting layer 913, an electron transport layer 914 (first electron transport layer 914-1, second electron transport layer 914-2), and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a substrate 900, a second electrode 903 is stacked on the electron injection layer 915, and a cap layer 904 is stacked on the second electrode 903.

[0411] First, a first electrode 901 was formed on the substrate 900. The electrode area was 4 mm². 2 The dimensions were set to (2mm x 2mm). A glass substrate was used for substrate 900. The first electrode 901 was formed by sequentially depositing silver to a thickness of 100nm and indium tin oxide (ITSO) containing silicon oxide to a thickness of 10nm using a sputtering method.

[0412] Here, as a pretreatment, the surface of the substrate was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. After that, 10 -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa. After vacuum firing at 170°C for 60 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0413] Next, a hole injection layer 911 was formed on the first electrode 901. The hole injection layer 911 was deposited in a vacuum deposition apparatus. -4After reducing the pressure to Pa, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as PCBBiF), represented by the above structural formula (i), and an electron acceptor material (OCHD-003) containing fluorine with a molecular weight of 672 were co-deposited at a weight ratio of 1:0.03 (=PCBBiF:OCHD-003) to form a 10 nm layer.

[0414] Next, a hole transport layer 912 was formed on the hole injection layer 911. The hole transport layer 912 was formed using PCBBiF by deposition at a 135 nm layer.

[0415] Next, a light-emitting layer 913 was formed on the hole transport layer 912.

[0416] The luminescent layer 913 contains 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzoflo[3,2-d]pyrimidine (abbreviated as 8BP-4mDBtPBfpm), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviated as βNCCP), and [2-d3-methyl-(2-pyridinyl-κN)benzo [2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as [Ir(ppy)2(mbfpypy-d3)]) was co-deposited with iridium(III) in a weight ratio of 8BP-4mDBtPBfpm:βNCCP:[Ir(ppy)2(mbfpypy-d3)]=0.6:0.4:0.05 to form a film thickness of 55 nm.

[0417] Next, an electron transport layer 914 was formed on the light-emitting layer 913. In this embodiment, the electron transport layer 914 has a laminated structure consisting of a first electron transport layer 914-1 and a second electron transport layer 914-2.

[0418] Light-emitting devices 1 and 2 were formed by depositing 8BP-4mDBtPBfpm as the first electron transport layer 914-1 to a thickness of 20 nm. Next, the second electron transport layer 914-2 was formed by depositing 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviated as 6,6'(P-Bqn)2BPy) to a thickness of 10 nm. The 8BP-4mDBtPBfpm used in the first electron transport layer 914-1 of light-emitting devices 1 and 2 has a temperature difference of 20°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state. Furthermore, the 6,6'(P-Bqn)2BPy used in the second electron transport layer 914-2 of light-emitting device 1 and light-emitting device 2 has a temperature difference of 100°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state.

[0419] Comparative light-emitting devices 3 and 4 were formed by depositing 8BP-4mDBtPBfpm as the first electron transport layer 914-1 to a thickness of 20 nm. Next, the second electron transport layer 914-2 was formed using 2,9-di(naphthalene-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviated as NBphen) to a thickness of 10 nm. The 8BP-4mDBtPBfpm used in the first electron transport layer 914-1 of comparative light-emitting devices 3 and 4 has a temperature difference of 20°C or less between its crystallization temperature (Tpc) in the powder state and its crystallization temperature (Ttc) in the thin film state. Furthermore, the NBphen used in the second electron transport layer 914-2 of comparative light-emitting devices 3 and 4 has a temperature difference of approximately 170°C between its crystallization temperature in powder state (Tpc) and its crystallization temperature in thin film state (Ttc).

[0420] Next, an electron injection layer 915 was formed on the electron transport layer 914. The electron injection layer 915 was formed by depositing lithium fluoride (LiF) to a thickness of 1 nm.

[0421] Next, a second electrode 903 was formed on the electron injection layer 915. The second electrode 903 was formed by co-evaporation using Ag and Mg in a weight ratio of 1:0.1 and with a film thickness of 15 nm. In this embodiment, the second electrode 903 functions as a cathode.

[0422] Next, a cap layer 904 was formed on the second electrode 903. The cap layer 904 was formed by depositing 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviated as DBT3P-II) to a thickness of 80 nm.

[0423] Through the above steps, light-emitting device 1, light-emitting device 2, comparative light-emitting device 3, and comparative light-emitting device 4 were fabricated, respectively. 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 steps are functional layers that constitute the EL layer in one aspect of the present invention. Furthermore, in the deposition steps of the above-described fabrication method, a deposition method using resistance heating was used for all steps.

[0424] Each fabricated light-emitting device was sealed in a glove box under a nitrogen atmosphere to prevent exposure to the air (sealant was applied around the element, UV treatment was performed during sealing, and heat treatment was performed at 80°C for 1 hour).

[0425] Finally, as mentioned above, light-emitting device 2 and comparative light-emitting device 4 are devices that underwent a heating treatment for 1 hour on a hot plate set to 120°C after obtaining the device characteristics of light-emitting device 1 and comparative light-emitting device 3.

[0426] Figure 22 shows the current-voltage characteristics of light-emitting device 1 and light-emitting device 2, Figure 23 shows the current efficiency-luminance characteristics of light-emitting device 1 and light-emitting device 2, Figure 24 shows the current-voltage characteristics of comparative light-emitting device 3 and comparative light-emitting device 4, Figure 25 shows the current efficiency-luminance characteristics of comparative light-emitting device 3 and comparative light-emitting device 4, and Figure 26 shows the emission spectra of light-emitting device 1, light-emitting device 2, comparative light-emitting device 3, and comparative light-emitting device 4. In addition, the emission spectra of light-emitting device 1, light-emitting device 2, comparative light-emitting device 3, and comparative light-emitting device 4 at 1000 cd / m² are shown. 2 Table 5 shows the main characteristics of the vicinity. Luminance, CIE chromaticity, and emission spectrum were measured using a spectroradiometer (Topcon SR-UL1R) at room temperature.

[0427] [Table 5]

[0428] As shown in Figure 22, it was found that in the case of light-emitting devices with the structures of light-emitting device 1 and light-emitting device 2, the effect of heat treatment on the current-voltage characteristics was almost negligible. In contrast, in the case of light-emitting devices with the structures of comparative light-emitting device 3 and comparative light-emitting device 4 shown in Figure 24, it was found that heat treatment caused changes in carrier injection and transport properties, resulting in an effect on the current-voltage characteristics.

[0429] Furthermore, as shown in Figure 23, it was found that for light-emitting devices with the structures of light-emitting device 1 and light-emitting device 2, the effect of heat treatment on the current efficiency-luminance characteristics was almost negligible. In contrast, for light-emitting devices with the structures of comparative light-emitting device 3 and comparative light-emitting device 4 shown in Figure 25, heat treatment changed the carrier balance, making carrier recombination more likely to occur on the low-luminance side of the current efficiency-luminance characteristics, thus affecting efficiency improvement. Moreover, in the EL spectra shown in Figure 26, no change in the EL spectra was observed for light-emitting devices with the structures of light-emitting device 1 and light-emitting device 2. On the other hand, a change in the EL spectra was observed for light-emitting devices with the structures of comparative light-emitting device 3 and comparative light-emitting device 4.

[0430] Generally, it is desirable that the device characteristics do not change even when the device is heated. In other words, since the light-emitting device according to one aspect of the present invention does not show any change in characteristics due to heating, it can be said to be a light-emitting device that has heat resistance in the manufacturing process. [Explanation of Symbols]

[0431] GD drive circuit IR subpixel M11 Transistor M12 Transistor M13 Transistor M14 Transistor M15 Transistor M16 Transistor M17 Transistor MS Wiring PS sub-pixels REG Resist Mask RES wiring SD drive circuit SE1 Wiring SE distance Si single crystal TX wiring VG wiring VS wiring 100 Light-emitting devices 100A Light-Emitting Device 100B Light-Emitting Device 100C Light-emitting Device 101 First electrode 102 Second electrode 103 EL layer 103a EL layer 103b EL layer 103B EL layer 103G EL layer 103R EL layer 104 Hole injection / transport layer 104B Hole Injection / Transport Layer 104G Hole Injection / Transport Layer 104R Hole Injection / Transport Layer 107 Insulating layer 107B Insulating layer 107G insulating layer 107R Insulating layer 108B-1, 108G-1, 108R-1: First electron transport layer 108B-2, 108G-2, 108R-2: Second electron transport layer 108B-1\108B-2 Electron transport layer 108G-1\108G-2 Electron transport layer 108R-1\108R-2 Electron transport layer 109 Electron injection layer 111 Hole injection layer 111a Hole injection layer 111b Hole injection layer 112 Hole transport layer 112a Hole transport layer 112b Hole transport layer 113 Emitting layer 113a Light-emitting layer 113b Emitting layer 113c emissive layer 113B Emitting layer 113G emissive layer 113R emissive layer 114 Electron transport layer 114a Electron transport layer 114b Electron transport layer 115 Electron injection layer 115a Electron injection layer 115b Electron injection layer 128 Bulkhead 150 areas 140 Second insulating layer 400 circuit boards 401 First electrode 403 EL layer 404 Second electrode 405 sealant 406 Sealant 407 Sealing substrate 412 pads 420 IC chips 501C insulating film 501D insulating film 504 Conductive film 506 Insulating film 508 Semiconductor film 508A area 508B area 508C area 510 First substrate 512A Conductive film 512B Conductive film 516 Insulating film 516A insulating film 516B insulating film 518 Insulating Film 520 Functional Layers 524 Conductive film 528 Bulkhead 530 pixel circuit 531 pixel circuit 530B Pixel Circuit 530G Pixel Circuit 532 Bulkhead 550 Light-emitting devices 550B Light-Emitting Device 550G Light-emitting Device 550R Light-Emitting Device 551B Electrode 551C connecting electrode 551G electrode 551R electrode 552 Electrode 580 Gap 591G Wiring 591B Wiring 700 Light-emitting devices 701 Display area 702G sub-pixels 702PS sub-pixels 702R sub-pixel 703 pixels 704 Circuit 705 Insulating layer 706 Wiring 710 circuit board 711 circuit board 712 IC 713 FPC 720 equipment 770 circuit boards 800 circuit boards 801a electrode 801b electrode 802 Electrode 803a EL layer 803b Photosensitive layer 805a Light-emitting device 805b Light receiving device 810 Display device 900 circuit boards 901 First electrode 903 Second electrode 904 Cap layer 911 Hole injection layer 912 Hole transport layer 913 Emitting layer 914 Electron transport layer 915 Electron injection layer 930 Insulating layer 950 Light-emitting devices 951 circuit board 952 Electrode 953 Insulating layer 954 Partition layer 955 EL layer 956 Electrode 5200B Electronic equipment 5210 Arithmetic unit 5220 Input / Output Device 5230 Display section 5240 Input Section 5250 Detection Unit 5290 Communications Department 8001 Ceiling Light 8002 Footlight 8003 Sheet-type lighting 8004 Lighting device 8005 Desk Lamp 8006 light source

Claims

1. having an EL layer between an anode and a cathode, the EL layer having at least a light-emitting layer and an electron transport layer, the electron transport layer having a first electron transport layer in contact with the light-emitting layer and a second electron transport layer in contact with the first electron transport layer, the first electron transport layer having a first heteroaromatic compound having at least one heteroaromatic ring, the second electron transport layer having at least one heteroaromatic ring and a second heteroaromatic compound different from the first heteroaromatic compound, the temperature difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state of the first heteroaromatic compound being within 20 °C, the second heteroaromatic compound having a difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state within 100 °C, a light-emitting device.

2. In claim 1, the heteroaromatic ring having any one of a pyridine ring, a diazine ring, a triazine ring, or a polyazole ring, a light-emitting device.

3. In claim 1 or claim 2, the heteroaromatic ring having a condensed heteroaromatic ring having a condensed ring structure, a light-emitting device.

4. In claim 3, the condensed heteroaromatic ring being any one of a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phthalazine ring, a benzimidazole ring, a light-emitting device.

5. In claim 1, The complex aromatic ring is any one of a pyrimidine ring, a pyrazine ring, a pyridazine ring, a triazine ring, a pyridine ring, a phenanthroline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a benzimidazole ring, a benzofuropyrimidine ring, or a benzofuropyrazine ring, and the light-emitting device.

6. A light-emitting device having the light-emitting device according to claim 1 or claim 2.

7. Having an adjacent first light-emitting device and a second light-emitting device, The first light-emitting device has a second electrode sandwiching a first EL layer on a first electrode, The first EL layer has at least a first light-emitting layer, a first electron transport layer, a second electron transport layer, and a first electron injection layer, The first electron transport layer is provided on the first light-emitting layer, and the second electron transport layer is provided on the first electron transport layer, A first insulating layer is provided in contact with side surfaces of the first light-emitting layer, the first electron transport layer, and the second electron transport layer, The first electron injection layer is provided on the second electron transport layer, The first insulating layer is located between side surfaces of the first light-emitting layer, the first electron transport layer, and the second electron transport layer and the first electron injection layer, The second light-emitting device has the second electrode sandwiching a second EL layer on a third electrode, The second EL layer has at least a second light-emitting layer, a third electron transport layer, a fourth electron transport layer, and a second electron injection layer, The third electron transport layer and the fourth electron transport layer are provided on the second light-emitting layer, A second insulating layer is provided in contact with side surfaces of the second light-emitting layer, the third electron transport layer, and the fourth electron transport layer, The first electron injection layer is provided on the fourth electron transport layer, The second insulating layer is located between the side surfaces of the second light-emitting layer, the third electron transport layer, and the fourth electron transport layer, and the first electron injection layer. The first electron transport layer and the third electron transport layer have a first heteroaromatic compound having at least one heteroaromatic ring. The second electron transport layer and the fourth electron transport layer have at least one heteroaromatic ring and have a second heteroaromatic compound different from the first heteroaromatic compound. For the first heteroaromatic compound, the temperature difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state is within 20 °C. The second heteroaromatic compound has a difference between the crystallization temperature (Tpc) in the powder state and the crystallization temperature (Ttc) in the thin film state within 100 °C, a light-emitting device.

8. In claim 7, The heteroaromatic ring has any one of a pyridine skeleton, a diazine skeleton, a triazine skeleton, or a polyazole skeleton, a light-emitting device.

9. In claim 7 or claim 8, The heteroaromatic ring has a condensed heteroaromatic ring having a condensed ring structure, a light-emitting device.

10. In claim 9, The condensed heteroaromatic ring is any one of a quinoline ring, a benzoquinoline ring, a quinoxaline ring, a dibenzoquinoxaline ring, a quinazoline ring, a benzoquinazoline ring, a dibenzoquinazoline ring, a phenanthroline ring, a phthalazine ring, a benzimidazole ring, a light-emitting device.

Images