Light-emitting devices

Abstract

To provide a novel light-emitting device that offers superior convenience, usefulness, or reliability. [Solution] A light-emitting device having a function to emit light, a first electrode, a second electrode, and a unit, wherein the light has a maximum peak at wavelength (lambda), the second electrode has a region that overlaps with the first electrode, and the unit has a region sandwiched between the first electrode and the second electrode. The unit comprises a first layer, a second layer, and a third layer, the first layer having a region sandwiched between the second layer and the third layer, and the first layer containing a light-emitting material. The second layer comprises a fourth layer and a fifth layer, the fifth layer having a region sandwiched between the fourth layer and the first layer. The fourth layer contains a first organic compound, the first organic compound having a first refractive index for light with wavelength (lambda), the fifth layer is in contact with the fourth layer, the fifth layer contains a second organic compound, the second organic compound having a second refractive index for light with wavelength (lambda), the second refractive index being smaller than the first refractive index.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a light-emitting device, a light-emitting apparatus, a display device, an electronic device, or a lighting apparatus.

[0002] Furthermore, 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, method, or method of manufacture. Alternatively, one aspect of the present invention relates to a process, machine, manufacture, or composition of matter. More specifically, examples of the technical field of one aspect of the present invention disclosed herein include semiconductor devices, display devices, light-emitting devices, energy storage devices, memory devices, methods for driving them, or methods for manufacturing them. [Background technology]

[0003] The practical application of light-emitting devices (organic electroluminescent 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 (holes and electrons) are injected, and by utilizing the recombination energy of these carriers, light emission can be obtained from the light-emitting material.

[0004] 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.

[0005] 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 or 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.

[0006] While displays or 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.

[0007] One of the problems often raised when discussing organic EL devices is their low light extraction efficiency. In particular, attenuation due to reflection caused by differences in refractive index between adjacent layers is a major factor in reducing the efficiency of the device. To mitigate this effect, a configuration has been proposed in which a layer made of a low refractive index material is formed inside the EL layer (see, for example, Patent Document 1).

[0008] Light-emitting devices with this configuration can achieve higher light extraction efficiency, and consequently higher external quantum efficiency, than light-emitting devices with conventional configurations. However, forming such a low refractive index layer within the EL layer without adversely affecting other important properties of the light-emitting device is not easy. This is because there is a trade-off between a low refractive index and high carrier transportability or reliability when used in a light-emitting device. This problem stems from the fact that carrier transportability or reliability in organic compounds largely depends on the presence of unsaturated bonds, and organic compounds with many unsaturated bonds tend to have high refractive indices. [Prior art documents] [Patent Documents]

[0009] [Patent Document 1] U.S. Patent Application Publication No. 2020 / 0176692 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] One aspect of the present invention aims to provide a novel light-emitting device that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel light-emitting apparatus that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel display device that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel electronic device that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel lighting device that is superior in convenience, usefulness, or reliability. Alternatively, it aims to provide a novel light-emitting device, a novel light-emitting apparatus, a novel display device, a novel electronic device, or a novel lighting device.

[0011] Furthermore, the description of these problems does not preclude the existence of other problems. Moreover, one aspect of the present invention does not need to solve all of these problems. Other problems will naturally become apparent from the description in the specification, drawings, and claims, and it is possible to extract other problems from the description in the specification, drawings, and claims. [Means for solving the problem]

[0012] (1) One aspect of the present invention is a light-emitting device having a function for emitting light, a first electrode, a second electrode, and a unit, wherein the light comprises a first spectrum φ1, and the first spectrum φ1 has a maximum peak at wavelength λ.

[0013] The second electrode has a region that overlaps with the first electrode, the unit has a region sandwiched between the first electrode and the second electrode, and the unit comprises a first layer, a second layer and a third layer.

[0014] The first layer comprises a region sandwiched between the second and third layers, and the first layer contains a luminescent material.

[0015] The second layer comprises a fourth layer and a fifth layer, and the fifth layer comprises a region sandwiched between the fourth layer and the first layer.

[0016] The fourth layer contains a first organic compound CTM1, which has a first refractive index n1 for light with a wavelength λ1 nm.

[0017] The fifth layer is in contact with the fourth layer, and the fifth layer contains the second organic compound CTM2. The second organic compound CTM2 has a second refractive index n2 for light with wavelength λ, and the second refractive index n2 is between 1.4 and 1.75.

[0018] (2) Another aspect of the present invention is a light-emitting device having a function for emitting light, a first electrode, a second electrode, and a unit, wherein the light comprises a first spectrum φ1, and the first spectrum φ1 has a maximum peak at a wavelength λ1 nm.

[0019] The second electrode has a region that overlaps with the first electrode, the unit has a region sandwiched between the first electrode and the second electrode, and the unit comprises a first layer, a second layer and a third layer.

[0020] The first layer comprises a region sandwiched between the second and third layers, and the first layer contains a luminescent material.

[0021] The second layer comprises a fourth layer and a fifth layer, and the fifth layer comprises a region sandwiched between the fourth layer and the first layer.

[0022] The fourth layer contains a first organic compound CTM1, which has a first refractive index n1 for light with a wavelength λ1 nm.

[0023] The fifth layer is in contact with the fourth layer, and the fifth layer contains the second organic compound CTM2, which has a second refractive index n2 for light with a wavelength of λ1 nm. Furthermore, the second refractive index n2 is smaller than the first refractive index n1.

[0024] (3) Another aspect of the present invention is the above-mentioned light-emitting device, wherein the first refractive index n1 has a difference of 0.1 or more and 1.0 or less between it and the second refractive index n2.

[0025] (4) Another aspect of the present invention is a light-emitting device having a first electrode, a second electrode, and a unit.

[0026] The second electrode has a region that overlaps with the first electrode, the unit has a region sandwiched between the first electrode and the second electrode, and the unit comprises a first layer, a second layer and a third layer.

[0027] The first layer comprises a region sandwiched between the second and third layers, and the first layer contains a luminescent material, which emits photoluminescent light. This photoluminescent light comprises a second spectrum φ2, which has a maximum peak at a wavelength λ2 nm.

[0028] The second layer comprises a region sandwiched between the first electrode and the first layer, the second layer comprises a fourth layer and a fifth layer, and the fifth layer comprises a region sandwiched between the fourth layer and the first layer.

[0029] The fourth layer contains a first organic compound CTM1, which has a first refractive index n1 for light with a wavelength λ2nm.

[0030] The fifth layer is in contact with the fourth layer, and the fifth layer contains the second organic compound CTM2. The second organic compound CTM2 has a second refractive index n2 for light with a wavelength λ2nm, and the second refractive index n2 is between 1.4 and 1.75.

[0031] (5) Another aspect of the present invention is a light-emitting device having a first electrode, a second electrode, and a unit.

[0032] The second electrode has a region that overlaps with the first electrode, the unit has a region sandwiched between the first electrode and the second electrode, and the unit comprises a first layer, a second layer and a third layer.

[0033] The first layer comprises a region sandwiched between the second and third layers, and the first layer contains a luminescent material, which emits photoluminescent light. This photoluminescent light comprises a second spectrum φ2, which has a maximum peak at a wavelength λ2 nm.

[0034] The second layer comprises a fourth layer and a fifth layer, and the fifth layer comprises a region sandwiched between the fourth layer and the first layer.

[0035] The fourth layer contains a first organic compound CTM1, which has a first refractive index n1 for light with a wavelength λ2nm.

[0036] The fifth layer is in contact with the fourth layer, and the fifth layer contains the second organic compound CTM2, which has a second refractive index n2 for light with a wavelength λ2nm. Furthermore, the second refractive index n2 is smaller than the first refractive index n1.

[0037] (6) Another aspect of the present invention is the above-mentioned light-emitting device, wherein the first refractive index n1 has a difference of 0.1 or more and 1.0 or less between it and the second refractive index n2.

[0038] (7) Another aspect of the present invention is a light-emitting device having a first electrode, a second electrode, and a unit.

[0039] The second electrode has a region that overlaps with the first electrode, the unit has a region sandwiched between the first electrode and the second electrode, and the unit comprises a first layer, a second layer and a third layer.

[0040] The first layer comprises a region sandwiched between the second and third layers, and the first layer contains a luminescent material that emits photoluminescent light. This photoluminescent light comprises a third spectrum φ3, which has a maximum peak at a wavelength λ3 nm.

[0041] The second layer comprises a region sandwiched between the first electrode and the first layer, the second layer comprises a fourth layer and a fifth layer, and the fifth layer comprises a region sandwiched between the fourth layer and the first layer.

[0042] The fourth layer contains a first organic compound CTM1, which has a first refractive index n1 for light with a wavelength λ3nm.

[0043] The fifth layer is in contact with the fourth layer, and the fifth layer contains the second organic compound CTM2. The second organic compound CTM2 has a second refractive index n2 for light with a wavelength λ3nm, and the second refractive index n2 is between 1.4 and 1.75.

[0044] (8) Another aspect of the present invention is a light-emitting device having a first electrode, a second electrode, and a unit.

[0045] The second electrode has a region that overlaps with the first electrode, the unit has a region sandwiched between the first electrode and the second electrode, and the unit comprises a first layer, a second layer and a third layer.

[0046] The first layer comprises a region sandwiched between the second and third layers, and the first layer contains a luminescent material that emits photoluminescent light. This photoluminescent light has a third spectrum φ3, which has a maximum peak at a wavelength λ3 nm.

[0047] The second layer comprises a fourth layer and a fifth layer, and the fifth layer comprises a region sandwiched between the fourth layer and the first layer.

[0048] The fourth layer contains a first organic compound CTM1, which has a first refractive index n1 for light with a wavelength λ3nm.

[0049] The fifth layer is in contact with the fourth layer, and the fifth layer contains the second organic compound CTM2, which has a second refractive index n2 for light with a wavelength λ3nm. Furthermore, the second refractive index n2 is smaller than the first refractive index n1.

[0050] (9) Another aspect of the present invention is the above-described light-emitting device wherein the first refractive index n1 has a difference of 0.1 or more and 1.0 or less between it and the second refractive index n2.

[0051] This allows for a change in refractive index between the fourth and fifth layers. Alternatively, the change in refractive index can be used to reflect light. Alternatively, the reflected light can be used to enhance the light emitted from the first layer. Alternatively, the efficiency of extracting light from the light-emitting device can be increased. Alternatively, the luminous efficiency of the light-emitting device can be increased. As a result, a novel light-emitting device with superior convenience, usefulness, or reliability can be provided.

[0052] (10) Another aspect of the present invention is the above-mentioned light-emitting device, wherein the fourth layer has a distance d between it and the first layer, and the distance is 20 nm or more and 120 nm or less.

[0053] (11) Another aspect of the present invention is the above-described light-emitting device, wherein the fourth layer has a distance d between it and the first layer, the first layer has a thickness t, and the distance d is within the range of thickness t, wavelength λ1 nm, second refractive index n2 and the following formula (1).

[0054]

number

[0055] This allows for a change in refractive index between the fourth and fifth layers. Alternatively, light can be reflected using the change in refractive index. Alternatively, the phase of the reflected light can be made to reinforce the light emitted from the first layer. Alternatively, a part of a micro-resonator structure can be formed inside the unit. Alternatively, the saturation of the emitted color can be increased. Alternatively, the efficiency of extracting light from the light-emitting device can be increased. Alternatively, the luminous efficiency of the light-emitting device can be increased. As a result, a novel light-emitting device with superior convenience, usefulness, or reliability can be provided.

[0056] (12) Another aspect of the present invention is the above-described light-emitting device wherein the fifth layer is in contact with the first layer, and the fifth layer has a function of suppressing the movement of carriers from the first layer to the fourth layer.

[0057] (13) In another aspect of the present invention, the second organic compound CTM2 is the above-mentioned light-emitting device having hole transport properties.

[0058] The second organic compound CTM2 has a first lowest unoccupied molecular orbital level (abbreviated as LUMO level), the first layer contains a host material, the host material has a second LUMO level, and the second LUMO level is lower than the first LUMO level.

[0059] (14) Another aspect of the present invention is the above-described light-emitting device in which the second organic compound CTM2 is an amine compound.

[0060] (15) Another aspect of the present invention is the above-described light-emitting device in which the first organic compound CTM1 is an amine compound.

[0061] (16) Another aspect of the present invention is the above-described light-emitting device in which the second organic compound CTM2 is a monoamine compound.

[0062] The monoamine compound comprises a group of aromatic groups and a nitrogen atom, the group of aromatic groups comprising a first aromatic group, a second aromatic group, and a third aromatic group.

[0063] The nitrogen atom is bonded to the first, second, and third aromatic groups, and the group of aromatic groups has substituents, which include sp3 carbons. The sp3 carbons form bonds with other atoms via sp3 hybrid orbitals, and sp3 carbons account for between 23% and 55% of the carbons in the monoamine compound.

[0064] (17) Another aspect of the present invention is a light-emitting device having the above-mentioned light-emitting device and a transistor or substrate.

[0065] (18) Another aspect of the present invention is a display device having the above-mentioned light-emitting device and a transistor or substrate.

[0066] (19) Another aspect of the present invention is a lighting device having the above-mentioned light-emitting device and a housing.

[0067] (20) Another aspect of the present invention is an electronic device having the above-mentioned display device, a sensor, an operation button, a speaker or a microphone.

[0068] In the drawings attached to this specification, components are classified by function and shown as independent blocks in block diagrams. However, in reality, it is difficult to completely separate components by function, and a single component may be involved in multiple functions.

[0069] In this specification, the term "light-emitting device" includes image display devices using light-emitting elements. Furthermore, modules in which a connector, such as an anisotropic conductive film or TCP (Tape Carrier Package), is attached to a light-emitting element, modules in which a printed circuit board is provided at the end of the TCP, or modules in which an IC (integrated circuit) is directly mounted to a light-emitting element using the COG (Chip On Glass) method may also be included as light-emitting devices. Additionally, lighting fixtures and the like may have light-emitting devices. [Effects of the Invention]

[0070] According to one aspect of the present invention, it is possible to provide a novel light-emitting device that is excellent in convenience, usefulness, or reliability. Alternatively, it is possible to provide a novel light-emitting apparatus that is excellent in convenience, usefulness, or reliability. Alternatively, it is possible to provide a novel display device that is excellent in convenience, usefulness, or reliability. Alternatively, it is possible to provide a novel electronic device that is excellent in convenience, usefulness, or reliability. Alternatively, it is possible to provide a novel lighting device that is excellent in convenience, usefulness, or reliability. Alternatively, it is possible to provide a novel light-emitting device, a novel light-emitting apparatus, a novel display device, a novel electronic device, or a novel lighting device.

[0071] 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]

[0072] [Figure 1] Figures 1A to 1D illustrate the configuration of a light-emitting device according to an embodiment. [Figure 2] Figures 2A and 2B illustrate the configuration of a light-emitting device according to an embodiment. [Figure 3] Figure 3 is a diagram illustrating the configuration of a functional panel according to an embodiment. [Figure 4] Figures 4A and 4B are conceptual diagrams of an active matrix type light-emitting device. [Figure 5] Figures 5A and 5B are conceptual diagrams of an active matrix type light-emitting device. [Figure 6] Figure 6 is a conceptual diagram of an active matrix type light-emitting device. [Figure 7] Figures 7A and 7B are conceptual diagrams of a passive matrix type light-emitting device. [Figure 8] Figures 8A and 8B are diagrams representing lighting devices. [Figure 9] Figures 9A, 9B1, 9B2, and 9C are diagrams representing electronic devices. [Figure 10] Figures 10A to 10C are diagrams representing electronic devices. [Figure 11] Figure 11 is a diagram representing a lighting device. [Figure 12] Figure 12 is a diagram representing a lighting device. [Figure 13] Figure 13 is a diagram representing an in-vehicle display device and lighting system. [Figure 14] Figures 14A to 14C are diagrams representing electronic devices. [Figure 15] Figures 15A to 15C illustrate the configuration of a light-emitting device according to an embodiment. [Figure 16] Figure 16 illustrates the current density-luminance characteristics of the light-emitting device according to the embodiment. [Figure 17] Figure 17 illustrates the brightness-current efficiency characteristics of the light-emitting device according to the embodiment. [Figure 18] Figure 18 illustrates the voltage-luminance characteristics of the light-emitting device according to the embodiment. [Figure 19] Figure 19 illustrates the voltage-current characteristics of the light-emitting device according to the embodiment. [Figure 20] Figure 20 illustrates the luminance-blue index characteristics of the light-emitting device according to the embodiment. [Figure 21] Figure 21 is a diagram illustrating the emission spectrum of a light-emitting device according to an embodiment. [Figure 22] Figure 22 illustrates the current density-luminance characteristics of the light-emitting device according to the embodiment. [Figure 23] Figure 23 illustrates the brightness-current efficiency characteristics of the light-emitting device according to the embodiment. [Figure 24] Figure 24 illustrates the voltage-luminance characteristics of the light-emitting device according to the embodiment. [Figure 25] Figure 25 illustrates the voltage-current characteristics of the light-emitting device according to the embodiment. [Figure 26]Figure 26 illustrates the luminance-external quantum efficiency characteristics of the light-emitting device according to the embodiment. [Figure 27] Figure 27 illustrates the emission spectrum of the light-emitting device according to the embodiment. [Modes for carrying out the invention]

[0073] A light-emitting device having a function to emit light, a first electrode, a second electrode, and a unit, wherein the light has a maximum peak at wavelength λ, the second electrode has a region overlapping with the first electrode, and the unit has a region sandwiched between the first electrode and the second electrode. The unit comprises a first layer, a second layer, and a third layer, the first layer having a region sandwiched between the second and third layers, and the first layer containing a light-emitting material. The second layer comprises a fourth layer and a fifth layer, the fifth layer having a region sandwiched between the fourth layer and the first layer. The fourth layer contains a first organic compound, the first organic compound having a first refractive index for light with wavelength λ, the fifth layer is in contact with the fourth layer, and the fifth layer contains a second organic compound, the second organic compound having a second refractive index for light with wavelength λ, the second refractive index being smaller than the first refractive index.

[0074] This can increase luminous efficiency, or even reliability. As a result, it is possible to provide novel light-emitting devices that are superior in convenience, usefulness, or reliability.

[0075] Embodiments will be described in detail 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 is not to be interpreted as being limited to the contents of the embodiments shown below. In the configuration of the invention described below, the same reference numerals are used in common across different drawings for the same parts or parts having similar functions, and repeated descriptions are omitted.

[0076] (Embodiment 1) In this embodiment, the configuration of a light-emitting device 150 according to one aspect of the present invention will be described with reference to Figure 1.

[0077] Figure 1A is a diagram illustrating the configuration of a light-emitting device according to one aspect of the present invention, Figure 1B is a diagram illustrating the spectrum of light emitted by a light-emitting device according to one aspect of the present invention, and Figure 1C is a diagram illustrating a part of the configuration of Figure 1A.

[0078] <Example Configuration of Light-Emitting Device 150 1> The light-emitting device 150 described in this embodiment has the function of emitting light EL1, and includes an electrode 101, an electrode 102, and a unit 103 (see Figure 1A). The light EL1 has a spectrum φ1, and the spectrum φ1 has a maximum peak at a wavelength λ1 nm (see Figure 1B). The electrode 102 has a region that overlaps with the electrode 101.

[0079] 《Example Configuration of Unit 103》 Unit 103 comprises a region sandwiched between electrodes 101 and 102, and includes layers 111, 112, and 113.

[0080] 《Example of Layer 111 Configuration 1》 Layer 111 comprises a region sandwiched between layers 112 and 113, and layer 111 contains a host material and a luminescent material.

[0081] 《Example of Layer 112 Configuration 1》 For example, a material with carrier transport properties can be used in layer 112. Specifically, a material with hole transport properties can be used in layer 112. It is preferable to use a material in layer 112 that has a larger band gap than the luminescent material contained in layer 111. This makes it possible to suppress energy transfer from excitons generated in layer 111 to layer 112.

[0082] [Example 1 of a material with hole transport properties] The hole mobility is 1 × 10⁻⁶. -6 cm 2Materials with a Vs of / Vs or higher can be suitably used as materials with hole transport properties.

[0083] For example, amine compounds or organic compounds having a π-electron-rich heteroaromatic ring skeleton can be used in hole-transporting materials. Specifically, compounds having an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, a furan skeleton, etc., can be used. Compounds having an aromatic amine skeleton or a carbazole skeleton are particularly preferred because they offer good reliability, high hole transportability, and contribute to reducing the driving voltage.

[0084] Examples of compounds having an aromatic amine skeleton include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviated as NPB), 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), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), and 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviated as PCBA1BP). ,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)triphenylamine (abbreviation: PCBNBB), 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), etc. can be used.

[0085] Examples of compounds having a carbazole skeleton include 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), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviated as PCCP), and the like.

[0086] Examples of compounds having a thiophene skeleton 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), 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviated as DBTFLP-IV), and others.

[0087] Examples of compounds having a furan skeleton include 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II), 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II), and others.

[0088] 《Example of Layer 112 Configuration 2》 Layer 112 comprises layers 112A and 112B, with layer 112B having a region sandwiched between layers 112A and 111.

[0089] 《Example of Layer 112A Configuration 1》 Layer 112A contains material CTM1. Material CTM1 has a refractive index n1 for light with a wavelength of λ1 nm.

[0090] 《Example of Layer 112B Configuration 1》 Layer 112B is in contact with layer 112A, and layer 112B contains material CTM2. Material CTM2 has a refractive index n2 for light with a wavelength λ1 nm, and the refractive index n2 is smaller than the refractive index n1.

[0091] This allows the refractive index to be changed between layers 112A and 112B. Alternatively, light can be reflected using the change in refractive index. Alternatively, the reflected light can be used to enhance the light emitted from layer 111. Alternatively, the efficiency of extracting light from the light-emitting device can be increased. Alternatively, the luminous efficiency of the light-emitting device can be increased. As a result, a novel light-emitting device with superior convenience, usefulness, or reliability can be provided.

[0092] Example 1 of material CTM2 Furthermore, materials with a refractive index of 1.4 to 1.75 can be suitably used in material CTM2.

[0093] For example, a hole-transporting material having a paraphotonic refractive index of 1.50 to 1.75 in the blue light emission region (455 nm to 465 nm), or a paraphotonic refractive index of 1.45 to 1.70 in 633 nm light, which is commonly used for refractive index measurement, can be used as material CTM2.

[0094] Furthermore, if anisotropy is present in the material, the refractive index for ordinary light and the refractive index for extraordinary light may differ. If the thin film to be measured is in such a state, anisotropy analysis can be performed to separate the refractive index for ordinary light and the refractive index for extraordinary light and calculate the refractive index of each. In this specification, if both ordinary and extraordinary refractive indices are present in the measured material, the ordinary refractive index is used as the index.

[0095] [Example 2 of materials with hole transport properties] One example of a material possessing hole transport properties is a monoamine compound having a first aromatic group, a second aromatic group, and a third aromatic group, wherein these first, second, and third aromatic groups are bonded to the same nitrogen atom.

[0096] The monoamine compound preferably has a ratio of 23% to 55% of the total number of carbon atoms in the molecule that form bonds via sp3 hybrid orbitals. 1Preferably, the compound is such that the integrated value of signals below 4 ppm exceeds the integrated value of signals at 4 ppm or higher in the result of measuring the monoamine compound by 1H-NMR.

[0097] Further, the monoamine compound preferably has at least one fluorene skeleton, and one or more of the first aromatic group, the second aromatic group, and the third aromatic group are fluorene skeletons.

[0098] Examples of the material having the above hole transporting property include organic compounds having structures such as the following general formula (G h1 1) to (G h1 4).

[0099]

Chemical formula

[0100] In the above general formula (G h1 1), Ar 1 , Ar 2 each independently represents a benzene ring or a substituent in which two or three benzene rings are bonded to each other. However, one or both of Ar 1 , Ar 2 has one or more hydrocarbon groups having 1 to 12 carbon atoms in which carbon forms bonds only with sp3 hybrid orbitals, and the total number of carbon atoms contained in all the hydrocarbon groups bonded to Ar 1 and Ar 2 is 8 or more, and the total number of carbon atoms contained in all the hydrocarbon groups bonded to either Ar 1 or Ar 2 is 6 or more. When a plurality of linear alkyl groups having 1 or 2 carbon atoms are bonded to Ar 1 or Ar 2 as hydrocarbon groups, the linear alkyl groups may be bonded to each other to form a ring.

[0101]

Chemical formula

[0102] The above general formula (G h1 In (2), m and r each independently represent 1 or 2, and m+r is 2 or 3. Also, t represents an integer from 0 to 4, and is preferably 0. 5 represents either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. Note that when m is 2, the type of substituents, the number of substituents, and the bond positions of the two phenylene groups may be the same or different, and when r is 2, the type of substituents, the number of substituents, and the bond positions of the two phenyl groups may be the same or different. Also, when t is an integer from 2 to 4, multiple R 5 Each of them may be the same or different, R 5 In this case, adjacent groups may be bonded to each other to form a ring.

[0103] [ka]

[0104] The above general formula (G h1 2) and (G h1 In 3), n and p each independently represent 1 or 2, and n+p is 2 or 3. s represents an integer from 0 to 4, and is preferably 0. Also, R 4 n represents either hydrogen or a hydrocarbon group having 1 to 3 carbon atoms. When n is 2, the type of substituents, the number of substituents, and the position of the bonds on the two phenylene groups may be the same or different. When p is 2, the type of substituents, the number of substituents, and the position of the bonds on the two phenyl groups may be the same or different. Also, when s is an integer from 2 to 4, multiple R 4 These can be the same or different.

[0105] [ka]

[0106] The above general formula (G h12)~(G h1 In 4), R 10 ~R 14 and R 20 ~R 24 Each of these independently represents a hydrocarbon group with 1 to 12 carbon atoms, in which hydrogen or carbon atoms form bonds solely through sp3 hybrid orbitals. 10 ~R 14 At least 3 of and R 20 ~R 24 It is preferable that at least 3 of them are hydrogen. As hydrocarbon groups having 1 to 12 carbon atoms in which carbon atoms form bonds only with sp3 hybrid orbitals, tert-butyl groups and cyclohexyl groups are preferred. However, R 10 ~R 14 and R 20 ~R 24 The total amount of carbon contained in is 8 or more, and R 10 ~R 14 or R 20 ~R 24 The total number of carbon atoms in either of the two is 6 or more. 4 , R 10 ~R 14 and R 20 ~R 24 In this case, adjacent groups may be bonded to each other to form a ring.

[0107] Also, the above general formula (G h1 1)~(G h1 4) In this case, u represents an integer from 0 to 4, and is preferably 0. If u is an integer from 2 to 4, multiple R 3 These can be the same or different. Also, R 1 , R 2 and R 3 Each of these independently represents an alkyl group having 1 to 4 carbon atoms, R 1 and R 2 They may be joined to each other to form a ring.

[0108] Furthermore, one of the materials having hole transport properties is preferably an arylamine compound having at least one aromatic group, wherein the aromatic group has first to third benzene rings and at least three alkyl groups. The first to third benzene rings are bonded in this order, and the first benzene ring is directly bonded to the nitrogen of the amine.

[0109] Furthermore, the first benzene ring may have substituted or unsubstituted phenyl groups, and it is preferable that it has unsubstituted phenyl groups. Also, the second or third benzene ring may have phenyl groups substituted with alkyl groups.

[0110] Furthermore, of the first to third benzene rings, two or more benzene rings, preferably all of them, do not have hydrogen directly bonded to the carbon atoms at positions 1 and 3. Instead, hydrogen is bonded to one of the first to third benzene rings, the alkyl-substituted phenyl group, the three alkyl groups, or the nitrogen atom of the amine.

[0111] Furthermore, the arylamine compound preferably has a second aromatic group. The second aromatic group is preferably an unsubstituted monocycle or a substituted or unsubstituted fused ring of three or fewer rings, and more preferably a substituted or unsubstituted fused ring of three or fewer rings, with the fused ring having 6 to 13 carbon atoms forming the ring, and even more preferably a group having a fluorene ring. Dimethylfluorenyl is preferred as the second aromatic group.

[0112] Furthermore, it is preferable that the above arylamine compound further has a third aromatic group. The third aromatic group is a group having one to three substituted or unsubstituted benzene rings.

[0113] The at least three alkyl groups mentioned above, and the alkyl group substituted for the phenyl group, are preferably chain alkyl groups having 2 to 5 carbon atoms. In particular, branched chain alkyl groups having 3 to 5 carbon atoms are preferred, and t-butyl groups are even more preferred.

[0114] Examples of materials with hole transport properties as described above include the following (G h2 1)~(G h2 Examples of organic compounds having a structure like that in 3) are given.

[0115] [ka]

[0116] Note that the above general formula (G h2 1) In Ar 101 represents a substituted or unsubstituted benzene ring, or a substituent consisting of two or three substituted or unsubstituted benzene rings bonded to each other.

[0117] [ka]

[0118] Note that the above general formula (G h2 In (2), x and y each independently represent 1 or 2, and x+y is 2 or 3. Also, R 109 represents an alkyl group with 1 to 4 carbon atoms, and w represents an integer from 0 to 4. Also, R 141 ~R 145 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or a cycloalkyl group having 5 to 12 carbon atoms. If w is 2 or more, there are multiple R 109 These may be the same or different. Also, if x is 2, the type of substituents, the number of substituents, and the position of the bond on the two phenylene groups may be the same or different. Also, if y is 2, the two R 141 ~R 145The types and number of substituents on the phenyl group having the same substituent may be the same or different.

[0119] [ka]

[0120] Note that the above general formula (G h2 3) In R 101 ~R 105 Each of these independently represents one of the following: hydrogen, a C1 to C6 alkyl group, a C6 to C12 cycloalkyl group, or a substituted or unsubstituted phenyl group.

[0121] Also, the above general formula (G h2 1)~(G h2 3) In R 106 , R 107 and R 108 Each of these independently represents an alkyl group having 1 to 4 carbon atoms, and v represents an integer from 0 to 4. Note that if v is 2 or greater, multiple R groups are used. 108 These can be the same or different. Also, R 111 ~R 115 One of the substituents is represented by the above general formula (g1), and the remaining ones each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, and a substituted or unsubstituted phenyl group. In addition, in the above general formula (g1), R 121 ~R 125 One of the substituents is represented by the above general formula (g2), and the remaining ones each independently represent one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, and a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms. In addition, in the above general formula (g2), R 131 ~R 135 Each of these independently represents one of the following: hydrogen, an alkyl group having 1 to 6 carbon atoms, or a phenyl group substituted with an alkyl group having 1 to 6 carbon atoms. 111 ~R 115 , R 121 ~R 125 and R 131 ~R 135Of these, at least 3 or more are alkyl groups having 1 to 6 carbon atoms, and R 111 to R 115 The number of substituted or unsubstituted phenyl groups is 1 or less, and R 121 to R 125 and R 131 to R 135 The number of phenyl groups substituted with alkyl groups having 1 to 6 carbon atoms is 1 or less. Also, among at least two combinations of the three combinations of R 112 and R 114 , R 122 and R 124 , and R 132 and R 134 in at least one of the combinations, at least one R is other than hydrogen.

[0122] Specifically, N,N-bis(4-cyclohexylphenyl)-N-(9,9-dimethyl-9H-fluoren-2yl)amine (abbreviation: dchPAF), N-(4-cyclohexylphenyl)-N-(3'',5''-diter-butyl-1,1''-biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2yl)amine (abbreviation: mmtBuBichPAF), N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-N-(4-cyclohexylphenyl)-9,9- Dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF), N-[(3,3',5'-t-butyl)-1,1'-biphenyl-5-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBichPAF), N-(1,1'-biphenyl-2-yl)-N-[(3,3',5'-tri-t-butyl)-1,1'-biphenyl-5-yl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBioFBi), N-(4-tert-butyl N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPtBuPAF), N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-02), N-(4-cyclohexylphenyl)-N-(3,3'',5' ,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-02), N-(1,1'-biphenyl-2-yl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-03), N-(4-cyclohexylphenyl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-03), etc., can be used in material CTM2.

[0123] Example of material CTM1 Furthermore, a material having a refractive index difference of 0.1 to 1.0 between its refractive index n2 and that of material CTM2 can be suitably used for material CTM1. Preferably, a material having a refractive index difference of 0.15 to 1.0 between its refractive index n2 and that of material CTM2 can be used for material CTM1. Even more preferably, a material having a refractive index difference of 0.2 to 1.0 between its refractive index n2 and that of material CTM2 can be used for material CTM1. Specifically, a material appropriately selected from the above-mentioned hole-transporting materials can be used for material CTM1.

[0124] <Example configuration of light-emitting device 150 2> The light-emitting device 150 described in this embodiment differs from the configuration example 1 of the light-emitting device 150 in that layer 111 emits photoluminescent light, and this photoluminescent light has a second spectrum φ2. Here, the differences will be described in detail, and the above description will be used as a reference for parts where a similar configuration can be used.

[0125] 《Example of Layer 111 Configuration 2》 Layer 111 emits photoluminescent light, which comprises a second spectrum φ2. The second spectrum φ2 has a maximum peak at a wavelength λ2 nm.

[0126] 《Example of Layer 112A Configuration 2》 Layer 112A contains material CTM1. Material CTM1 has a refractive index n1 for light with a wavelength λ2nm.

[0127] 《Example of Layer 112B Configuration 2》 Layer 112B is in contact with layer 112A, and layer 112B contains material CTM2. Material CTM2 has a refractive index n2 for light with a wavelength λ2nm, and the refractive index n2 is smaller than the refractive index n1.

[0128] <Example configuration of light-emitting device 150 3> The light-emitting device 150 described in this embodiment differs from the configuration example 1 of the light-emitting device 150 in that layer 111 includes a light-emitting material, the light-emitting material emits photoluminescent light, and the photoluminescent light has a third spectrum φ3. Here, the differences will be described in detail, and the above description will be used as a reference for parts where a similar configuration can be used.

[0129] 《Example of Layer 111 Configuration 3》 Layer 111 contains a luminescent material, which emits photoluminescent light. This photoluminescent light also comprises a third spectrum φ3, which has a maximum peak at a wavelength λ3 nm. The photoluminescence of the luminescent material can be observed, for example, when the luminescent material is dissolved in a solvent. For instance, the photoluminescence of the luminescent material can be observed when dissolved in a polar solvent, a nonpolar solvent, or water. Specifically, toluene, dichloromethane, acetonitrile, etc., can be used as solvents. Toluene is particularly suitable.

[0130] 《Example of Layer 112A Configuration 3》 Layer 112A contains material CTM1. Material CTM1 has a refractive index n1 for light with a wavelength λ3nm.

[0131] 《Example of Layer 112B Configuration 3》 Layer 112B is in contact with layer 112A, and layer 112B contains material CTM2. Material CTM2 has a refractive index n2 for light with a wavelength λ3nm, and the refractive index n2 is smaller than the refractive index n1.

[0132] 《Example of Layer 112A Configuration 4》 Furthermore, layer 112A has a distance d between it and layer 111. For example, the distance d is between 20 nm and 120 nm.

[0133] 《Example Configuration of Unit 103 2》 Furthermore, the light-emitting device 150 described in this embodiment has a configuration of unit 103 that is represented by the following equation. In the equation, d is the distance between layer 112A and layer 111, t is the thickness of layer 111, λ is the wavelength of the maximum peak in the emission spectrum, and n2 is the refractive index of material CTM2 for light with wavelength λnm (see Figure 1A).

[0134]

number

[0135] Furthermore, the wavelength λ1nm at which the maximum peak is observed in the spectrum of light emitted by the light-emitting device 150 can be used as the wavelength λnm. Alternatively, the wavelength λ2nm at which the maximum peak is observed in the spectrum of photoluminescent light emitted by layer 111 can be used as the wavelength λnm. Alternatively, the wavelength λ3nm at which the maximum peak is observed in the spectrum of photoluminescent light emitted by the luminescent material contained in layer 111 can be used as the wavelength λnm.

[0136] This allows the refractive index to be changed between layers 112A and 112B. Alternatively, light can be reflected using the change in refractive index. Alternatively, the phase of the reflected light can be made to a phase that reinforces the light emitted from layer 111. Alternatively, a part of a micro-resonator structure can be formed inside unit 103. Alternatively, the saturation of the emitted color can be increased. Alternatively, the efficiency of extracting light from the light-emitting device can be increased. Alternatively, the luminous efficiency of the light-emitting device can be increased. As a result, a novel light-emitting device with superior convenience, usefulness, or reliability can be provided.

[0137] 《Example of Layer 112 Configuration 4》 Furthermore, in one aspect of the present invention, layer 112B is in contact with layer 111, and layer 112B has a function to suppress the movement of carriers from layer 111 to layer 112A. For example, layer 112B has a function to suppress the movement of electrons.

[0138] Example 2 of material CTM2 Material CTM2 possesses hole transport properties and has a LUMO level LUMO1 (see Figure 1C).

[0139] 《Example of Layer 111 Configuration 4》 Layer 111 contains host material. The host material (HOST) has a LUMO level LUMO2, which is lower than the LUMO level LUMO1.

[0140] This makes it possible to suppress the movement of electrons from layer 111 to layer 112A. Alternatively, it can increase the probability of electrons and holes recombining in layer 111. Alternatively, it can increase luminescence efficiency. Alternatively, it can improve reliability. As a result, it is possible to provide a novel light-emitting device that is superior in convenience, usefulness, or reliability.

[0141] 《Example of Layer 113 Configuration 1》 For example, electron-transporting materials, materials with an anthracene skeleton, and mixed materials can be used for layer 113. Layer 113 can also be referred to as an electron transport layer. It is preferable to use a material with a larger band gap for layer 113 than the luminescent material contained in layer 111. This suppresses energy transfer from excitons generated in layer 111 to layer 113.

[0142] [Materials with electron transport properties] For example, metal complexes or organic compounds having a π-electron-deficient heteroaromatic ring skeleton can be used as electron-transporting materials.

[0143] Under the condition that the square root of the electric field strength [V / cm] is 600, the electron mobility is 1 × 10⁻⁶. -7 cm2 / Vs or more, 5×10 -5 cm 2 Materials with a Vs of 0.5 / Vs or less can be suitably used as electron-transporting materials. This allows for control of electron transport in the electron transport layer, control of the amount of electrons injected into the light-emitting layer, or prevention of the light-emitting layer becoming electron-excessive.

[0144] Examples of metal complexes that can be used include 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), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviated as ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviated as ZnBTZ), and the like.

[0145] Organic compounds having a π-electron-deficient heteroaromatic ring skeleton include, for example, heterocyclic compounds having a polyazole skeleton, heterocyclic compounds having a diazine skeleton, heterocyclic compounds having a pyridine skeleton, and heterocyclic compounds having a triazine skeleton. In particular, heterocyclic compounds having a diazine skeleton or a pyridine skeleton are preferred due to their good reliability. Furthermore, heterocyclic compounds having a diazine (pyrimidine or pyrazine) skeleton have high electron transport properties, which can reduce the driving voltage.

[0146] Examples of heterocyclic compounds having a polyazole skeleton include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviated as PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviated as TAZ), and 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazole-2-yl]benzene (abbreviated as O XD-7), 9-[4-(5-phenyl-1,3,4-oxadiazole-2-yl)phenyl]-9H-carbazole (abbreviated as CO11), 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), etc. can be used.

[0147] Examples of heterocyclic compounds having a diazine skeleton include 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), and 2-[3'-(9H-carbazole-9-yl)biphenyl-3-yl]dibenzo[f,h Quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthren-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzo[h]quinazoline (abbreviation: 4,8mDBtP2Bqn), etc. can be used.

[0148] Examples of heterocyclic compounds having a pyridine skeleton include 3,5-bis[3-(9H-carbazole-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), and others.

[0149] Examples of heterocyclic compounds having a triazine skeleton include 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn) and 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1,3,5-triazine (abbreviation: BP- SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), etc. can be used.

[0150] [Materials containing an anthracene skeleton] Organic compounds having an anthracene skeleton can be used in layer 113. In particular, organic compounds containing both an anthracene skeleton and a heterocyclic skeleton can be preferably used.

[0151] For example, an organic compound containing both an anthracene skeleton and a nitrogen-containing five-membered ring skeleton can be used. Alternatively, an organic compound containing both a nitrogen-containing five-membered ring skeleton with two heteroatoms in the ring and an anthracene skeleton can be used. Specifically, pyrazole rings, imidazole rings, oxazole rings, thiazole rings, etc., can be suitably used as the heterocyclic skeleton.

[0152] For example, an organic compound containing both an anthracene skeleton and a nitrogen-containing six-membered ring skeleton can be used. Alternatively, an organic compound containing both a nitrogen-containing six-membered ring skeleton with two heteroatoms in the ring and an anthracene skeleton can be used. Specifically, pyrazine rings, pyrimidine rings, pyridazine rings, etc., can be suitably used as the heterocyclic skeleton.

[0153] [Example of mixed material composition] Furthermore, a material composed of a mixture of multiple substances can be used in layer 113. Specifically, a mixed material containing an alkali metal, alkali metal compound, or alkali metal complex and an electron-transporting substance can be used in layer 113. It is more preferable that the highest occupied molecular orbital level (abbreviated as HOMO level) of the electron-transporting material is -6.0 eV or higher.

[0154] Furthermore, the mixed material can be suitably used in layer 113 in combination with a configuration in which the composite material is used in layer 104. For example, a composite material of a substance having acceptor properties and a material having hole transport properties can be used in layer 104. Specifically, a composite material of a substance having acceptor properties and a substance having a relatively deep HOMO level HOMO1 between -5.7 eV and -5.4 eV can be used in layer 104 (see Figure 1D). In particular, the mixed material can be suitably used in layer 113 in combination with a configuration in which the composite material is used in layer 104. This can improve the reliability of the light-emitting device.

[0155] Furthermore, the configuration in which the mixed material is used as layer 113 and the composite material as layer 104 can be suitably combined with a configuration in which a hole-transporting material is used as layer 112. For example, a material having a HOMO level HOMO2 in the range of -0.2 eV to 0 eV relative to the relatively deep HOMO level HOMO1 can be used as layer 112 (see Figure 1D). This can improve the reliability of the light-emitting device.

[0156] A configuration in which alkali metals, alkali metal compounds, or alkali metal complexes are present in the thickness direction of layer 113 with a concentration difference (including cases where the concentration is zero) is preferred.

[0157] For example, metal complexes containing an 8-hydroxyquinolinate structure can be used. Alternatively, methyl-substituted metal complexes containing an 8-hydroxyquinolinate structure (e.g., 2-methyl-substituted or 5-methyl-substituted) can also be used.

[0158] As metal complexes containing the 8-hydroxyquinolinate structure, 8-hydroxyquinolinate-lithium (abbreviated as Liq), 8-hydroxyquinolinate-sodium (abbreviated as Naq), etc., can be used. In particular, monovalent metal ion complexes are preferred, among lithium complexes, and Liq is more preferred.

[0159] 《Example of Layer 113 Configuration 2》 Layer 113 comprises layer 113A and layer 113B, with layer 113A having a region sandwiched between layer 113B and layer 111.

[0160] 《Example of Layer 113B Configuration 1》 Layer 113B contains material CTM12. Material CTM12 has a refractive index n12 for light with a wavelength λ1 nm.

[0161] 《Example of Layer 113A Configuration》 Layer 113A is in contact with layer 113B, and layer 113A contains material CTM11. Material CTM11 has a refractive index n11 for light with a wavelength λ1nm, and the refractive index n11 is smaller than the refractive index n12.

[0162] Example 1 of material CTM11 Furthermore, materials with a refractive index of 1.4 to 1.75 can be suitably used in material CTM11.

[0163] For example, an electron-transporting material having a paraphotonic refractive index of 1.50 to 1.75 in the blue light emission region (455 nm to 465 nm), or a paraphotonic refractive index of 1.45 to 1.70 in 633 nm light, which is commonly used for refractive index measurement, can be used as material CTM11.

[0164] Furthermore, if anisotropy is present in the material, the refractive index for ordinary light and the refractive index for extraordinary light may differ. If the thin film to be measured is in such a state, anisotropy analysis can be performed to separate the refractive index for ordinary light and the refractive index for extraordinary light and calculate the refractive index of each. In this specification, if both ordinary and extraordinary refractive indices are present in the measured material, the ordinary refractive index is used as the index.

[0165] [Materials with electron transport properties] One example of an electron-transporting material is an organic compound having at least one six-membered heteroaromatic ring containing one to three nitrogen atoms, multiple aromatic hydrocarbon rings with 6 to 14 carbon atoms forming the ring, at least two of which are benzene rings, and multiple hydrocarbon groups that form bonds with sp3 hybrid orbitals.

[0166] Furthermore, it is preferable that the proportion of carbon atoms forming bonds via sp3 hybrid orbitals relative to the total number of carbon atoms in the molecule of such an organic compound is 10% to 60%, and more preferably 10% to 50%. Alternatively, such an organic compound may be 1 It is preferable that the integral value of signals less than 4 ppm in the measurement of the organic compound by 1H-NMR is at least half the integral value of signals of 4 ppm or more.

[0167] Furthermore, it is preferable that the hydrocarbon groups forming bonds in all sp3 hybrid orbitals of the organic compound are bonded to an aromatic hydrocarbon ring having 6 to 14 carbon atoms that forms the above-mentioned ring, and that the LUMO of the organic compound is not distributed in that aromatic hydrocarbon ring.

[0168] The following general formula (G e1 1) or (G e1 The organic compound represented in 2) is preferred.

[0169] [ka]

[0170] In the formula, A represents a six-membered heteroaromatic ring containing 1 to 3 nitrogen atoms, and is preferably a pyridine ring, pyrimidine ring, pyrazine ring, pyridazine ring, or triazine ring.

[0171] Also, R 200 This includes hydrogen, an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or a group of the formula (G e1 It represents any of the substituents represented in 1-1).

[0172] R 201 ~R 215 At least one of the members is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C10 alicyclic group, a substituted or unsubstituted C6 to C14 aromatic hydrocarbon group forming a ring, or a substituted or unsubstituted pyridyl group. 201 , R 203 , R 205 , R 206 , R 208 , R 210 , R 211 , R 213 and R 215 It is preferable that is hydrogen. The substituted phenyl group has one or two substituents, each substituent independently being one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring.

[0173] Note that the above general formula (G e1 The organic compound represented in 1) has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the proportion of the total number of carbon atoms that form bonds in sp3 hybrid orbitals relative to the total number of carbon atoms in the molecule is between 10% and 60%.

[0174] Furthermore, the following general formula (G e1 The organic compound represented in 2) is preferred.

[0175] [ka]

[0176] In the formula, Q 1 ~Q 3 Two or three of them represent N, and Q 1 ~Q 3 If two of them are N, the remaining one represents CH.

[0177] Also R 201 ~R 215 At least one of the members is a substituted phenyl group, and the others each independently represent one of the following: hydrogen, a C1 to C6 alkyl group, a C3 to C10 alicyclic group, a substituted or unsubstituted C6 to C14 aromatic hydrocarbon group forming a ring, or a substituted or unsubstituted pyridyl group. 201 , R 203 , R 205 , R 206 , R 208 , R 210 , R 211 , R 213 and R 215 It is preferable that is hydrogen. The substituted phenyl group has one or two substituents, each substituent independently being one of the following: an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring.

[0178] Note that the above general formula (G e1 The organic compound represented in 2) preferably has multiple hydrocarbon groups selected from alkyl groups having 1 to 6 carbon atoms and alicyclic groups having 3 to 10 carbon atoms, and the proportion of carbon atoms forming bonds in sp3 hybrid orbitals relative to the total number of carbon atoms in the molecule is preferably 10% to 60%.

[0179] Also, the above general formula (G e1 1) or (G e1 In the organic compound represented by (2), the substituted phenyl group is of the following formula (G e1It is preferable that the group is represented by 1-2).

[0180] [ka]

[0181] In the formula, α represents a substituted or unsubstituted phenylene group, and is preferably a meta-substituted phenylene group. Furthermore, if the meta-substituted phenylene group has one substituent, it is preferable that this substituent is also meta-substituted. The substituent is preferably a C1 to C6 alkyl group or a C3 to C10 alicyclic group, more preferably a C1 to C6 alkyl group, and even more preferably a t-butyl group.

[0182] R 220 This represents an alkyl group having 1 to 6 carbon atoms, an alicyclic group having 3 to 10 carbon atoms, or an aromatic hydrocarbon group having 6 to 14 carbon atoms that forms a substituted or unsubstituted ring.

[0183] Furthermore, j and k represent 1 to 2. Note that when j is 2, the multiple αs may be the same or different. Also, when k is 2, multiple R 220 These can be the same or different. Note that R 220 The substituent is preferably a phenyl group, and is a phenyl group having a C1 to C6 alkyl group or a C3 to C10 alicyclic group at one or both of its two meta positions. More preferably, the substituents on one or both of the two meta positions of the phenyl group are C1 to C6 alkyl groups, and even more preferably t-butyl groups.

[0184] Specifically, 2-{(3’,5’-di-tert-butyl)-1,1’-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3,5-triazine (abbreviation: mmtBumBP-dmmtBuPTzn), 2-{(3’,5’-di-tert-butyl)-1,1’-biphenyl-3-yl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumBPTzn), 2-(3,3’’,5,5’’-tetra-tert-butyl-1,1’:3’,1’’-terphenyl-5-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumTPTzn), 2-{(3’,5’-di-tert-butyl)-1,1’-biphenyl-3-yl}-4,6-bis(3,5-di-tert-butylphenyl)-1,3-pyrimidine (abbreviation: mmtBumBP-dmmtBuPPm), 2-(3,3’’,5’,5’’-tetra-tert-butyl-1,1’:3’,1’’-terphenyl-5-yl)-4,6-diphenyl-1,3,5-triazine (abbreviation: mmtBumTPTzn-02), etc. can be used for Material CTM11.

[0185] 《Examples of Material CTM12》 In addition, materials having a difference of 0.1 or more and 1.0 or less from the refractive index n11 of Material CTM11 can be preferably used for Material CTM12. Further preferably, materials having a difference of 0.15 or more and 1.0 or less from the refractive index n11 of Material CTM11 can be used for Material CTM12. More preferably, materials having a difference of 0.2 or more and 1.0 or less from the refractive index n11 of Material CTM11 can be used for Material CTM12. Specifically, materials appropriately selected from the above materials having electron transporting properties can be used for Material CTM12.

[0186] 《Configuration Example 2 of Layer 113B》 In addition, Layer 113B has a distance d2 from Layer 111. For example, the distance d2 is 20 nm or more and 120 nm or less.

[0187] 《Configuration Example 3 of Unit 103》 In addition, the light-emitting device 150 described in this embodiment has a relationship in which the configuration of the unit 103 is represented by the following formula. In the formula, d2 is the distance between the layer 113B and the layer 111, t is the thickness of the layer 111, λ is the wavelength of the maximum peak of the emission spectrum, and n11 is the refractive index of the material CTM11 with respect to light having a wavelength of λ nm (see FIG. 1A).

[0188] [Number]

[0189] Note that, in the spectrum of the light emitted by the light-emitting device 150, the wavelength λ1 nm at which the maximum peak is observed can be used as the wavelength λ nm. Alternatively, in the spectrum of the photoluminescence light emitted by the layer 111, the wavelength λ2 nm at which the maximum peak is observed can be used as the wavelength λ nm. Alternatively, in the spectrum of the photoluminescence light emitted by the light-emitting material contained in the layer 111, the wavelength λ3 nm at which the maximum peak is observed can be used as the wavelength λ nm.

[0190] Thereby, the luminous efficiency can be increased. As a result, a novel light-emitting device excellent in convenience, usefulness, or reliability can be provided.

[0191] <Example 3 of the Configuration of Layer 113> In addition, in one aspect of the present invention, the layer 113A is in contact with the layer 111, and the layer 113A has a function of suppressing the movement of carriers from the layer 111 toward the layer 113B. For example, the layer 113A has a function of suppressing the movement of holes.

[0192] <Example 2 of Material CTM11> The material CTM11 has electron transporting properties, and the material CTM11 has a HOMO level HOMO3.

[0193] <Example 5 of the Configuration of Layer 111> The layer 111 contains a host material. The host material has a HOMO level HOMO4, and the HOMO level HOMO4 is higher than the HOMO level HOMO3.

[0194] This makes it possible to suppress the movement of electrons from layer 111 to layer 113B, or to increase the probability of electrons and holes recombining in layer 111, or to increase luminescence efficiency, or to improve reliability. As a result, it is possible to provide a novel light-emitting device that is superior in convenience, usefulness, or reliability.

[0195] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0196] (Embodiment 2) In this embodiment, the configuration of a light-emitting device 150 according to one aspect of the present invention will be described with reference to Figure 1A.

[0197] <Example configuration of light-emitting device 150> The light-emitting device 150 described in this embodiment includes an electrode 101, an electrode 102, and a unit 103. Electrode 102 has a region that overlaps with electrode 101, and unit 103 has a region sandwiched between electrode 101 and electrode 102.

[0198] <Example configuration of Unit 103> Unit 103 comprises layers 111, 112, and 113 (see Figure 1A).

[0199] Layer 111 includes a region sandwiched between layers 112 and 113, layer 112 includes a region sandwiched between electrode 101 and layer 111, and layer 113 includes a region sandwiched between electrode 102 and layer 111.

[0200] For example, a layer selected from functional layers such as an emissive layer, a hole transport layer, an electron transport layer, and a carrier block layer can be used in unit 103. Furthermore, a layer selected from functional layers such as a hole injection layer, an electron injection layer, an exciton block layer, and a charge generation layer can also be used in unit 103.

[0201] 《Example of Layer 111 Configuration 1》 For example, a light-emitting material, or a light-emitting material and a host material, can be used for layer 111. Layer 111 can also be referred to as a light-emitting layer. It is preferable to position layer 111 in a region where holes and electrons recombine. This allows the energy generated by carrier recombination to be efficiently emitted as light. It is also preferable to position layer 111 away from metals used in electrodes, etc. This suppresses quenching caused by metals used in electrodes, etc.

[0202] For example, fluorescent materials, phosphorescent materials, or materials exhibiting thermally delayed fluorescence (TADF) (also known as TADF materials) can be used as luminescent materials. This allows the energy generated by carrier recombination to be released from the luminescent material as photo-EL1 (see Figure 1A).

[0203] [Fluorescent material] A fluorescent material can be used in layer 111. For example, the fluorescent materials exemplified below can be used in layer 111. However, this is not limited to these examples, and various known fluorescent materials can be used in layer 111.

[0204] Specifically, 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'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyren-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren- 9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-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), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N ,9-diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviation: DBC1), coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazole-3-amine (abbreviation: 2PCAPA), 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: 2DPA BPhA), 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-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinoridine-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluorantene-3,10-di Amine (abbreviation: 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]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. can be used.,

[0205] In particular, condensed aromatic diamine compounds represented by pyrene diamine compounds such as 1,6FLPAPrn or 1,6mMemFLPAPrn, 1,6BnfAPrn-03 are preferable because they have high hole trapping properties and are excellent in luminescence efficiency or reliability.,

[0206] [Phosphorescent luminescent substance] A phosphorescent luminescent substance can be used for layer 111. For example, the phosphorescent luminescent substances exemplified below can be used for layer 111. Note that it is not limited thereto, and various known phosphorescent luminescent substances can be used for layer 111.,

[0207] For example, organometallic iridium complexes having a 4H-triazole skeleton, organometallic iridium complexes having a 1H-triazole skeleton, organometallic iridium complexes having an imidazole skeleton, organometallic iridium complexes with a phenylpyridine derivative having an electron-withdrawing group as a ligand, organometallic iridium complexes having a pyrimidine skeleton, organometallic iridium complexes having a pyrazine skeleton, organometallic iridium complexes having a pyridine skeleton, rare earth metal complexes, platinum complexes, etc., can be used in layer 111.

[0208] [Phosphorescent material (blue)] Examples of organometallic iridium complexes having a 4H-triazole skeleton include tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazole-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)-5-isopropyl-3-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(iPrptz-3b)3]), etc.

[0209] Examples of organometallic iridium complexes having a 1H-triazole skeleton include tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III) (abbreviation: [Ir(Mptz1-mp)3]), tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), etc.

[0210] Examples of organometallic iridium complexes having an imidazole skeleton include fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridine]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), etc.

[0211] Examples of organometallic iridium complexes using phenylpyridine derivatives having electron-withdrawing groups as ligands include 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’ Iridium(III) acetylacetonate (abbreviated as FIracac), etc., can be used.

[0212] These compounds exhibit blue phosphorescence and have emission wavelength peaks between 440 nm and 520 nm.

[0213] [Phosphorescent material (green)] Examples of organometallic iridium complexes having a pyrimidine skeleton include tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [ Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]), etc. can be used.

[0214] Examples of organometallic iridium complexes having a pyrazine skeleton include (acetylacetonato)bis(3,5-dimethyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]), (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyradinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]), etc.

[0215] Examples of organometallic iridium complexes having a pyridine skeleton include tris(2-phenylpyridinato-N,C) 2’ Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinate-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)]), [2-d3-methyl-(2-pyridinyl-κN)benzoflou[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridyl-κN2)phenyl-κ]iridium(III) (abbreviation: [Ir(5mppy-d3)2(mbfpypy-d3)]), [2-d3-methyl-(2-pyridinyl-κN)benzoflou[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)), etc. can be used.

[0216] Examples of rare earth metal complexes include tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviation: [Tb(acac)3(Phen)]).

[0217] These compounds primarily exhibit green phosphorescence and have emission wavelength peaks between 500 nm and 600 nm. Furthermore, organometallic iridium complexes with a pyrimidine skeleton are remarkably superior in terms of reliability or luminescence efficiency.

[0218] [Phosphorescent material (red)] Examples of organometallic iridium complexes having a pyrimidine skeleton include (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), bis[4,6-di(naphthalene-1-yl)pyrimidinato](dipvaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), etc.

[0219] Examples of organometallic iridium complexes having a pyrazine skeleton include (acetylacetonato)bis(2,3,5-triphenylpyradinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyradinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), etc.

[0220] Examples of organometallic iridium complexes having a pyridine skeleton include 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)]), etc., can be used.

[0221] Examples of rare earth metal complexes that can be used include tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]), tris[1-(2-tenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]), etc.

[0222] Examples of platinum complexes that can be used include 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (abbreviated as PtOEP).

[0223] These compounds exhibit red phosphorescence and have an emission peak between 600 nm and 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton produce red emission with a chromaticity suitable for use in display devices.

[0224] [Substances exhibiting thermally activated delayed fluorescence (TADF)] TADF material can be used for layer 111. For example, the TADF material exemplified below can be used as the luminescent material. However, it is not limited to this, and various known TADF materials can be used as the luminescent material.

[0225] TADF materials have a small difference between the S1 and T1 energy levels, allowing for reverse intersystem crossing (upconversion) from a triplet excited state to a singlet excited state with minimal thermal energy. This enables efficient generation of singlet excited states from triplet excited states. Furthermore, the triplet excitation energy can be converted into luminescence.

[0226] Furthermore, an excited complex (also called an exciplex) that forms an excited state with two types of substances 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.

[0227] Furthermore, the phosphorescence spectrum observed at low temperatures (e.g., 77K to 10K) can be used as an indicator of the T1 level. For TADF materials, when a tangent is drawn at the short-wavelength tail of the fluorescence spectrum and the energy at the wavelength of the extrapolation is taken as the S1 level, and when a tangent is drawn at the short-wavelength tail of the phosphorescence spectrum and the energy at the wavelength of the extrapolation is taken as the T1 level, it is preferable that the difference between S1 and T1 is 0.3 eV or less, and more preferably 0.2 eV or less.

[0228] Furthermore, when using TADF material as a light-emitting material, it is preferable that the S1 level of the host material is higher than the S1 level of the TADF material. Also, it is preferable that the T1 level of the host material is higher than the T1 level of the TADF material.

[0229] For example, fullerenes and their derivatives, acridines and their derivatives, eosin derivatives, etc., can be used as TADF materials. In addition, metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd), etc., can be used as TADF materials.

[0230] Specifically, the following can be used: protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), octaethylporphyrin-platinum chloride complex (PtCl2OEP), etc., whose structural formulas are shown below.

[0231] [ka]

[0232] Furthermore, for example, heterocyclic compounds having one or both of a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring can be used as TADF materials.

[0233] Specifically, the structural formulas are as follows: 2-(biphenyl-4-yl)-4,6-bis(12-phenylindoro[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazol (abbreviation: PCCzTzn), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazine-10-yl)phenyl] -4,6-diphenyl-1,3,5-triazine (abbreviated as PXZ-TRZ), 3-[4-(5-phenyl-5,10-dihydrophenazine-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviated as PPZ-3TPT), 3-(9,9-dimethyl-9H-acridine-10-yl)-9H-xanthene-9-one (abbreviated as ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviated as DMAC-DPS), 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviated as ACRSA), etc. can be used.

[0234] [ka]

[0235] The heterocyclic compound is preferred because it has both a π-electron-excess heteroaromatic ring and a π-electron-deficient heteroaromatic ring, resulting in high electron transport and hole transport properties. In particular, among the skeletons having a π-electron-deficient heteroaromatic ring, the pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, the benzoflopyrimidine skeleton, benzothienopyrimidine skeleton, benzoflopyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptability and are reliable.

[0236] Furthermore, among skeletons having a π-electron-excess heteroaromatic ring, the acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are stable and reliable, and therefore it is preferable to have at least one of these skeletons. Dibenzofuran is preferred as the furan skeleton, and dibenzothiophene is preferred as the thiophene skeleton. Indole, carbazole, indrocarbazole, bicarbazole, and 3-(9-phenyl-9H-carbazole-3-yl)-9H-carbazole are particularly preferred as the pyrrole skeleton.

[0237] Furthermore, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because both the electron-donating and electron-accepting properties of the π-electron-rich heteroaromatic ring are strengthened, resulting in a smaller energy difference between the S1 and T1 levels, thus efficiently obtaining thermally activated delayed fluorescence. Alternatively, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used instead of the π-electron-deficient heteroaromatic ring. Additionally, aromatic amine skeletons, phenazine skeletons, and the like can be used as the π-electron-rich skeleton.

[0238] Furthermore, as π-electron-deficient skeletons, xanthene skeletons, thioxanthene dioxide skeletons, oxadiazole skeletons, triazole skeletons, imidazole skeletons, anthraquinone skeletons, boron-containing skeletons such as phenylborane or volanthrene, aromatic rings or heteroaromatic rings having a nitrile group or cyano group such as benzonitrile or cyanobenzene, carbonyl skeletons such as benzophenone, phosphine oxide skeletons, sulfone skeletons, and the like can be used.

[0239] Thus, a π-electron-deficient skeleton and a π-electron-excess skeleton can be used instead of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-excess heteroaromatic ring.

[0240] 《Example of Layer 111 Configuration 2》 Materials with carrier transport properties can be used as host materials. For example, materials with hole transport properties, materials with electron transport properties, substances that exhibit thermally delayed fluorescence (TADF), materials with an anthracene skeleton, and mixed materials can be used as host materials.

[0241] [Materials with hole transport properties] The hole mobility is 1 × 10⁻⁶. -6 cm 2 Materials with a Vs of / Vs or higher can be suitably used as materials with hole transport properties.

[0242] For example, a hole-transporting material that can be used in layer 112 can be used in layer 111. Specifically, a hole-transporting material that can be used in a hole-transporting layer can be used in layer 111.

[0243] [Materials with electron transport properties] For example, an electron-transporting material that can be used in layer 113 can be used in layer 111. Specifically, an electron-transporting material that can be used in an electron transport layer can be used in layer 111.

[0244] [Materials containing an anthracene skeleton] Organic compounds having an anthracene skeleton can be used as host materials. In particular, organic compounds having an anthracene skeleton are suitable when fluorescent materials are used as the light-emitting material. This makes it possible to realize light-emitting devices with good luminescence efficiency and durability.

[0245] Among organic compounds having an anthracene skeleton, organic compounds having a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, are preferred because they are chemically stable. Furthermore, when the host material has a carbazole skeleton, it is preferred because the hole injection and transport properties are enhanced. In particular, when the host material contains a dibenzocarbazole skeleton, the HOMO becomes about 0.1 eV shallower than that of carbazole, making it easier for holes to enter, and it is also preferred because it has excellent hole transport properties and high heat resistance. From the viewpoint of hole injection and transport properties, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of a carbazole skeleton.

[0246] Therefore, substances having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton, substances having both a 9,10-diphenylanthracene skeleton and a benzocarbazole skeleton, and substances having both a 9,10-diphenylanthracene skeleton and a dibenzocarbazole skeleton are preferred as host materials.

[0247] For example, 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-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-phenyl-3-[4-(10-phenyl [Lu-9-anthryl)phenyl]-9H-carbazole (abbreviated as PCzPA), 9-[4-(10-phenyl-9-antracenyl)phenyl]-9H-carbazole (abbreviated as CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviated as cgDBCzPA), 3-[4-(1-naphthyl)phenyl]-9-phenyl-9H-carbazole (abbreviated as PCPN), etc. can be used.

[0248] In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA exhibit very good characteristics.

[0249] [Substances exhibiting thermally activated delayed fluorescence (TADF)] TADF material can be used for layer 111. For example, the TADF material exemplified below can be used as the host material. However, it is not limited to this, and various known TADF materials can be used as the host material.

[0250] When a TADF material is used as the host material, the triplet excitation energy generated by the TADF material can be converted into singlet excitation energy through reverse intersystem crossing. Furthermore, the excitation energy can be transferred to the light-emitting material. In other words, the TADF material functions as an energy donor, and the light-emitting material functions as an energy acceptor. This can increase the luminescence efficiency of the light-emitting device.

[0251] This is particularly effective when the light-emitting material is a fluorescent material. Furthermore, in order to obtain high luminescence efficiency, it is preferable that the S1 level of the TADF material is higher than that of the fluorescent material. Also, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material. Therefore, it is preferable that the T1 level of the TADF material is higher than that of the fluorescent material.

[0252] Furthermore, it is preferable to use a TADF material that exhibits emission that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material. This is preferable because it allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient emission.

[0253] Furthermore, for singlet excitation energy to be efficiently generated from triplet excitation energy by reverse intersystem crossing, it is preferable that carrier recombination occurs in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to the triplet excitation energy of the fluorescent substance. To achieve this, it is preferable that the fluorescent substance has protecting groups around the luminescent phosphoform (the skeleton that causes luminescence). Preferred protecting groups are substituents without π bonds, and saturated hydrocarbons are preferred. Specifically, examples include alkyl groups having 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups having 3 to 10 carbon atoms, and trialkylsilyl groups having 3 to 10 carbon atoms. It is even more preferable to have multiple protecting groups. Substituents without π bonds have poor carrier transport function, and therefore can increase the distance between the TADF material and the luminescent phosphoform of the fluorescent substance with little effect on carrier transport or carrier recombination.

[0254] Here, the term "luminescent phosphat" refers to the group of atoms (skeleton) that causes light emission in a fluorescent material. The luminescent phosphat preferably has a skeleton with π bonds, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring.

[0255] Examples of condensed aromatic rings or condensed heteroaromatic rings include phenanthrene skeletons, stilbene skeletons, acridone skeletons, phenoxazine skeletons, and phenothiazine skeletons. In particular, fluorescent materials having naphthalene skeletons, anthracene skeletons, fluorene skeletons, chrysene skeletons, triphenylene skeletons, tetracene skeletons, pyrene skeletons, perylene skeletons, coumarin skeletons, quinacridone skeletons, and naphthobisbenzofuran skeletons are preferred because they have high fluorescence quantum yields.

[0256] For example, TADF material, which can be used as a luminescent material, can be used as a host material.

[0257] [Example of mixed material composition 1] Furthermore, a material composed of a mixture of multiple substances can be used as the host material. For example, a material with electron-transporting properties and a material with hole-transporting properties can be used in the mixture. The weight ratio of the material with hole-transporting properties to the material with electron-transporting properties in the mixture should be such that the ratio of material with hole-transporting properties to the material with electron-transporting properties is 1:19 to 19:1. This allows for easy adjustment of the carrier transport properties of layer 111. In addition, the recombination region can be easily controlled.

[0258] [Example of mixed material composition 2] Materials mixed with phosphorescent materials can be used as host materials. When using fluorescent materials as the light-emitting material, the phosphorescent material can be used as an energy donor to supply excitation energy to the fluorescent material.

[0259] A mixed material containing a material that forms an excited complex can be used as the host material. For example, a material in which the emission spectrum of the formed excited complex overlaps with the wavelength of the lowest-energy absorption band of the luminescent substance can be used as the host material. This allows for smoother energy transfer and improved luminescence efficiency, or it can suppress the driving voltage.

[0260] A phosphorescent material can be used in at least one of the materials forming the excitation complex. This allows for the utilization of reverse intersystem crossing. Alternatively, the triplet excitation energy can be efficiently converted to the singlet excitation energy.

[0261] For a combination of materials to form an excited complex, it is preferable that the HOMO level of the hole-transporting material is higher than or equal to the HOMO level of the electron-transporting material. Alternatively, it is preferable that the LUMO level of the hole-transporting material is higher than or equal to the LUMO level of the electron-transporting material. This allows for efficient formation of the excited complex. The LUMO and HOMO levels of the materials can be derived from their electrochemical properties (reduction potential and oxidation potential). Specifically, the reduction potential and oxidation potential can be measured using cyclic voltammetry (CV) measurement.

[0262] The formation of excited complexes can be confirmed, for example, by comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film made by mixing these materials, and observing that the emission spectrum of the mixed film shifts to a longer wavelength than the emission spectra of each individual material (or has a new peak on the longer wavelength side). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and the transient PL of a mixed film made by mixing these materials, and observing differences in the transient response, such as the transient PL lifetime of the mixed film having a longer lifetime component or a larger proportion of the delayed component than the transient PL lifetime of each individual material. Furthermore, the transient PL mentioned above can be replaced with transient electroluminescence (EL). That is, the formation of excited complexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and the transient EL of a mixed film made by mixing these materials, and observing the differences in the transient response.

[0263] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0264] (Embodiment 3) In this embodiment, the configuration of a light-emitting device 150 according to one aspect of the present invention will be described with reference to Figure 1A.

[0265] <Example configuration of light-emitting device 150> The light-emitting device 150 described in this embodiment includes an electrode 101, an electrode 102, a unit 103, and a layer 104. Electrode 102 has a region that overlaps with electrode 101, and unit 103 has a region sandwiched between electrode 101 and electrode 102. Layer 104 also has a region sandwiched between electrode 101 and unit 103. For example, the configuration described in Embodiment 1 and Embodiment 2 can be used for unit 103.

[0266] <Example configuration of electrode 101> For example, conductive materials can be used for the electrode 101. Specifically, metals, alloys, conductive compounds, and mixtures thereof can be used for the electrode 101. For example, materials with a work function of 4.0 eV or higher can be suitably used.

[0267] For example, indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, tungsten oxide, and indium oxide containing zinc oxide (IWZO) can be used.

[0268] In addition, for example, gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or nitrides of metallic materials (e.g., titanium nitride) can be used. Alternatively, graphene can be used.

[0269] Example of Layer 104 configuration For example, a material with hole-injection properties can be used for layer 104. Layer 104 can also be referred to as a hole-injection layer.

[0270] Specifically, a material with acceptor properties can be used in layer 104. Alternatively, a composite material of a material with acceptor properties and a material with hole transport properties can be used in layer 104. This makes it easier to inject holes, for example, from electrode 101. Alternatively, it can reduce the driving voltage of the light-emitting device.

[0271] [Substances with acceptability] Organic and inorganic compounds can be used as acceptor materials. Acceptor materials can extract electrons from adjacent hole transport layers or hole transport materials by applying an electric field.

[0272] For example, compounds having electron-withdrawing groups (halogen or cyano groups) can be used as acceptor materials. Furthermore, organic compounds with acceptor properties are easily vapor-deposited and readily formed into films. This can increase the productivity of light-emitting devices.

[0273] Specifically, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviated as F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (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.

[0274] In particular, compounds in which an electron-withdrawing group is bonded to a condensed aromatic ring having multiple heteroatoms, such as HAT-CN, are thermally stable and therefore preferred.

[0275] Furthermore, radialene derivatives having electron-withdrawing groups (especially halogen groups such as fluoro groups or cyano groups) [3] are preferred because they have very high electron-accepting properties.

[0276] 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], α,α',α''-1,2,3-cyclopropanetriylidenates[2,3,4,5,6-pentafluorobenzeneacetonitrile], etc., can be used.

[0277] Furthermore, molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc., can be used as acceptor materials.

[0278] Furthermore, phthalocyanine-based complex compounds such as phthalocyanine (abbreviated as H2Pc) or copper phthalocyanine (CuPc), and compounds having an aromatic amine skeleton such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD) can be used.

[0279] Furthermore, polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (PEDOT / PSS) can be used.

[0280] [Example of composite material composition 1] Furthermore, materials composed of multiple types of substances can be used as materials with hole injection properties. For example, a material with acceptor properties and a material with hole transport properties can be used as a composite material. This allows not only materials with large work functions but also materials with small work functions to be used for the electrode 101. Alternatively, the material to be used for the electrode 101 can be selected from a wide range of materials, regardless of the work function.

[0281] For example, compounds having an aromatic amine skeleton, carbazole derivatives, aromatic hydrocarbons, aromatic hydrocarbons having a vinyl group, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used as hole transport materials in composite materials. Furthermore, if the hole mobility is 1 × 10⁻⁶ -6 cm 2 Materials with a Vs of 1 / V or higher can be suitably used as materials with hole transport properties in composite materials.

[0282] Furthermore, materials with relatively deep HOMO levels can be suitably used as hole-transporting materials in composite materials. Specifically, it is preferable that the HOMO level is between -5.7 eV and -5.4 eV, as this facilitates the injection of holes into unit 103, or into layer 112, or improves the reliability of the light-emitting device.

[0283] Examples of compounds having an aromatic amine skeleton include N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviated as DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviated as DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviated as DPA3B).

[0284] Examples of carbazole derivatives include 3-[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA1), 3,6-bis[N-(9-phenylcarbazole-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviated as PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazole-3-yl)amino]-9-phenyl Carbazole (abbreviated as PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviated as CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviated as TCPB), 9-[4-(N-carbazolyl)]phenyl-10-phenylanthracene (abbreviated as CzPA), 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene, etc. can be used.

[0285] Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), and 2-tert-butyl-9,10 -Bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, 2,5,8,11-tetra(tert-butyl)perylene, pentacene, coronene, etc. can be used.

[0286] Examples of aromatic hydrocarbons having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviated as DPVBi), 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviated as DPVPA), and the like.

[0287] Examples of polymer compounds that can be used include poly(N-vinylcarbazole) (abbreviated as PVK), poly(4-vinyltriphenylamine) (abbreviated as PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviated as PTPDMA), poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviated as Poly-TPD), and the like.

[0288] Furthermore, for example, substances comprising any of the carbazole skeleton, dibenzofuran skeleton, dibenzothiophene skeleton, and anthracene skeleton can be suitably used as hole-transporting materials in composite materials. In addition, substances comprising aromatic amines having substituents including a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group can be used as hole-transporting materials in composite materials. Moreover, using a substance having an N,N-bis(4-biphenyl)amino group can improve the reliability of light-emitting devices.

[0289] Examples of these materials include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)-4''-phenyltriphenylamine (abbreviation: BnfBB1BP), and 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''-diphenyltriphenylamine (abbreviation: BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-0 3) 4,4'-diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-Diphenyl-4''-(5;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4 ''-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-diphenyl-4'-(2-naphthyl)-4''-{9-(4-biphenylyl)carbazole)}triphenylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi(9H-fluorene)-2-amine (abbreviation: PCBNBSF), N,N-bis(4-biphenylyl)-9 ,9'-Spirobi[9H-Fluorene]-2-amine (abbreviation: BBASF), N,N-Bis(1,1'-Biphenyl-4-yl)-9,9'-Spirobi[9H-Fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-Biphenyl-2-yl)-N-(9,9-Dimethyl-9H-Fluorene-2-yl)-9,9'-Spirobi(9H-Fluorene)-4-amine (abbreviation: oFBiSF), N-(4-Biphenyl)-N-(Dibenzofuran-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-[4-(9-phenyl [Fluoren-9-yl)phenyl]triphenylamine (abbreviation: BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl (Lu)-4''-(9-phenyl-9H-carbazole-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]spiro-9,9'-bifluoren-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9H-fluoren-2-amine (abbreviation: PCBBiF), N,N-bis(9,9- Dimethyl-9H-fluoren-2-yl)-9,9'-spirobio-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. can be used.

[0290] [Example of composite material composition 2] For example, a composite material containing an acceptor, a hole transporter, and an alkali metal fluoride or alkaline earth metal fluoride can be used as a hole injection material. In particular, a composite material in which fluorine atoms make up 20% or more of the atomic ratio can be suitably used. This can lower the refractive index of layer 104. Alternatively, a layer with a low refractive index can be formed inside the light-emitting device. Alternatively, the external quantum efficiency of the light-emitting device can be improved.

[0291] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0292] (Embodiment 4) In this embodiment, the configuration of a light-emitting device 150 according to one aspect of the present invention will be described with reference to Figure 1A.

[0293] <Example configuration of light-emitting device 150> The light-emitting device 150 described in this embodiment includes an electrode 101, an electrode 102, a unit 103, and a layer 105. Electrode 102 has a region that overlaps with electrode 101, and unit 103 has a region sandwiched between electrode 101 and electrode 102. Layer 105 also has a region sandwiched between unit 103 and electrode 102. For example, the configuration described in any of Embodiments 1 to 3 can be used for unit 103.

[0294] <Example configuration of electrode 102> For example, conductive materials can be used for electrode 102. Specifically, metals, alloys, conductive compounds, and mixtures thereof can be used for electrode 102. For example, a material with a smaller work function than electrode 101 can be suitably used for electrode 102. Specifically, a material with a work function of 3.8 eV or less is preferred.

[0295] For example, elements belonging to Group 1 of the periodic table, elements belonging to Group 2 of the periodic table, rare earth metals, and alloys containing these can be used for the electrode 102.

[0296] Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), strontium (Sr), europium (Eu), ytterbium (Yb), and alloys containing these elements (MgAg, AlLi) can be used for electrode 102.

[0297] Example of Layer 105 configuration For example, an electron-injection material can be used for layer 105. Layer 105 can also be referred to as an electron-injection layer.

[0298] Specifically, a donor material can be used in layer 105. Alternatively, a composite material of a donor material and an electron-transporting material can be used in layer 105. Alternatively, an electride can be used in layer 105. This makes it easier to inject electrons, for example, from electrode 102. Alternatively, not only materials with a small work function but also materials with a large work function can be used in electrode 102. Alternatively, a material for electrode 102 can be selected from a wide range of materials, regardless of the work function. Specifically, Al, Ag, ITO, silicon, or indium oxide-tin oxide containing silicon oxide can be used in electrode 102. Alternatively, the driving voltage of the light-emitting device can be reduced.

[0299] [Substances with donor properties] For example, alkali metals, alkaline earth metals, rare earth metals, or compounds thereof (oxides, halides, carbonates, etc.) can be used as donor substances. Alternatively, organic compounds such as tetratianaphthalene (abbreviated as TTN), nickerosene, and decamethylnickerosene can also be used as donor substances.

[0300] Examples of alkali metal compounds (including oxides, halides, and carbonates) that can be used include lithium oxide, lithium fluoride (LiF), cesium fluoride (CsF), lithium carbonate, cesium carbonate, 8-hydroxyquinolinatolithium (abbreviated as Liq), etc.

[0301] As alkaline earth metal compounds (including oxides, halides, and carbonates), calcium fluoride (CaF2), etc., can be used.

[0302] [Examples of composite material compositions] Furthermore, materials composed of multiple types of substances can be used as materials with electron injection properties. For example, a donor substance and an electron transport material can be used as a composite material. Also, for example, an electron transport material that can be used in unit 103 can be used as a composite material.

[0303] Furthermore, a composite material can be made from a microcrystalline alkali metal fluoride and an electron-transporting material. Alternatively, a composite material can be made from a microcrystalline alkaline earth metal fluoride and an electron-transporting material. In particular, a composite material containing 50 wt% or more of alkali metal fluoride or alkaline earth metal fluoride can be suitably used. Alternatively, a composite material containing an organic compound having a bipyridine skeleton can be suitably used. This can lower the refractive index of layer 104, or improve the external quantum efficiency of the light-emitting device.

[0304] [Electride] For example, a material obtained by adding a high concentration of electrons to a mixed oxide of calcium and aluminum can be used as an electron-injection material.

[0305] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0306] (Embodiment 5) In this embodiment, the configuration of a light-emitting device 150 according to one aspect of the present invention will be described with reference to Figure 2A.

[0307] Figure 2A is a cross-sectional view illustrating the configuration of a light-emitting device according to one embodiment of the present invention.

[0308] <Example configuration of light-emitting device 150> Furthermore, the light-emitting device 150 described in this embodiment includes an electrode 101, an electrode 102, a unit 103, and an intermediate layer 106 (see Figure 2A). Electrode 102 has a region that overlaps with electrode 101, and unit 103 has a region sandwiched between electrode 101 and electrode 102. The intermediate layer 106 has a region sandwiched between unit 103 and electrode 102.

[0309] 《Example of the configuration of the intermediate layer 106》 The intermediate layer 106 comprises layer 106A and layer 106B. Layer 106B includes a region sandwiched between layer 106A and electrode 102.

[0310] 《Example of Layer 106A Configuration》 For example, an electron-transporting material can be used for layer 106A. Layer 106A can also be referred to as an electron relay layer. Using layer 106A allows the layer in contact with the anode side of layer 106A to be separated from the layer in contact with the cathode side of layer 106A. This reduces the interaction between the layer in contact with the anode side of layer 106A and the layer in contact with the cathode side of layer 106A. Electrons can be smoothly supplied to the layer in contact with the anode side of layer 106A.

[0311] A material having a LUMO level between the LUMO level of an acceptor material contained in the layer in contact with the anode side of layer 106A and the LUMO level of a material contained in the layer in contact with the cathode side of layer 106A can be suitably used in layer 106A.

[0312] For example, a material having a LUMO level in the range of -5.0 eV or higher, preferably -5.0 eV to -3.0 eV, can be used for layer 106A.

[0313] Specifically, phthalocyanine-based materials can be used in layer 106A. Alternatively, metal complexes having metal-oxygen bonds and aromatic ligands can be used in layer 106A.

[0314] Example of layer 106B configuration For example, a material that supplies electrons to the anode side and holes to the cathode side when a voltage is applied can be used for layer 106B. Specifically, electrons can be supplied to unit 103 located on the anode side. Layer 106B can also be called a charge generation layer.

[0315] Specifically, a hole-injection material that can be used in layer 104 can be used in layer 106B. For example, a composite material can be used in layer 106B. Alternatively, for example, a laminated film obtained by laminating a film containing the composite material with a film containing a hole-transporting material can be used in layer 106B.

[0316] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0317] (Embodiment 6) In this embodiment, the configuration of a light-emitting device 150 according to one aspect of the present invention will be described with reference to Figure 2B.

[0318] Figure 2B is a cross-sectional view illustrating the configuration of a light-emitting device according to one embodiment of the present invention, which has a configuration different from that shown in Figure 2A.

[0319] <Example configuration of light-emitting device 150> The light-emitting device 150 described in this embodiment includes an electrode 101, an electrode 102, a unit 103, an intermediate layer 106, and a unit 103(12) (see Figure 2B). Electrode 102 has a region that overlaps with electrode 101, unit 103 has a region sandwiched between electrode 101 and electrode 102, and intermediate layer 106 has a region sandwiched between unit 103 and electrode 102. Unit 103(12) also has a region sandwiched between intermediate layer 106 and electrode 102.

[0320] The configuration comprising the intermediate layer 106 and multiple units is sometimes referred to as a stacked light-emitting device or a tandem light-emitting device. This allows for high-brightness light emission while maintaining a low current density. Alternatively, reliability can be improved. Alternatively, the drive voltage can be reduced when comparing devices with the same brightness. Alternatively, power consumption can be suppressed.

[0321] 《Example configuration of Unit 103(12)》 The configuration that can be used in unit 103 can also be used in unit 103(12). In other words, the light-emitting device 150 has multiple stacked units. Note that the number of stacked units is not limited to two, and three or more units can be stacked.

[0322] The same configuration as unit 103 can be used for unit 103(12). Alternatively, a different configuration from unit 103 can be used for unit 103(12).

[0323] For example, a configuration in unit 103(12) with a different emission color from that of unit 103 can be used. Specifically, a unit 103 that emits red and green light and a unit 103(12) that emits blue light can be used. This makes it possible to provide a light-emitting device that emits light of a desired color. For example, a light-emitting device that emits white light can be provided.

[0324] 《Example of the configuration of the intermediate layer 106》 The intermediate layer 106 has the function of supplying electrons to one of the units 103 or 103(12) and holes to the other. For example, the intermediate layer 106 described in Embodiment 5 can be used.

[0325] <Method for fabricating the light-emitting device 150> For example, the electrodes 101, 102, unit 103, intermediate layer 106, and unit 103(12) can be formed using dry, wet, vapor deposition, droplet ejection, coating, or printing methods. Furthermore, different methods can be used to form each component.

[0326] Specifically, the light-emitting device 150 can be manufactured using a vacuum deposition system, an inkjet system, a coating system such as a spin coater, a gravure printing system, an offset printing system, a screen printing system, and the like.

[0327] For example, electrodes can be formed using a wet method or a sol-gel method with a paste of a metallic material. Specifically, an indium oxide-zinc oxide film can be formed by sputtering using a target containing 1 to 20 wt% zinc oxide relative to indium oxide. Alternatively, an indium oxide (IWZO) film containing tungsten oxide and zinc oxide can be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide relative to indium oxide.

[0328] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0329] (Embodiment 7) In this embodiment, the configuration of a light-emitting panel 700 according to one aspect of the present invention will be described with reference to Figure 3.

[0330] <Example configuration of the light-emitting panel 700> The light-emitting panel 700 described in this embodiment has a light-emitting device 150 and a light-emitting device 150(2) (Figure 3).

[0331] For example, the light-emitting devices described in Embodiments 1 to 6 can be used in the light-emitting device 150.

[0332] <Example configuration of light-emitting device 150(2)> The light-emitting device 150(2) described in this embodiment has an electrode 101(2), an electrode 102, and a unit 103(2) (see Figure 3). Electrode 102 has a region that overlaps with electrode 101(2). Note that a part of the configuration of the light-emitting device 150 can be used as a part of the configuration of the light-emitting device 150(2). This allows for the commonality of some components, or simplifies the manufacturing process.

[0333] 《Example configuration of Unit 103(2)》 Unit 103(2) comprises a region sandwiched between electrodes 101(2) and 102, and unit 103(2) comprises a layer 111(2).

[0334] Unit 103(2) comprises a single-layer structure or a multi-layer structure. For example, layers selected from functional layers such as a hole transport layer, an electron transport layer, a carrier block layer, and an exciton block layer can be used in Unit 103(2).

[0335] Unit 103(2) includes a region where electrons injected from one electrode recombine with holes injected from the other electrode. For example, it includes a region where holes injected from electrode 101(2) recombine with electrons injected from electrode 102.

[0336] 《Example of Layer 111(2) Configuration 1》 Layer 111(2) contains a light-emitting material and a host material. Layer 111(2) can also be called a light-emitting layer. It is preferable to position layer 111(2) in a region where holes and electrons recombine. This allows the energy generated by carrier recombination to be efficiently emitted as light. It is also preferable to position layer 111(2) away from metals used in electrodes, etc. This suppresses the quenching phenomenon caused by metals used in electrodes, etc.

[0337] For example, a different luminescent material can be used in layer 111(2) than the luminescent material used in layer 111. Specifically, luminescent materials with different emission colors can be used in layer 112(2). This allows for the arrangement of light-emitting devices with different hues. Alternatively, additive color mixing can be performed using multiple light-emitting devices with different hues. Or, colors with hues that cannot be displayed by individual light-emitting devices can be represented.

[0338] For example, a light-emitting device that emits blue light, a light-emitting device that emits green light, and a light-emitting device that emits red light can be placed on the functional panel. Alternatively, a light-emitting device that emits white light, a light-emitting device that emits yellow light, and a light-emitting device that emits infrared light can be placed on the functional panel.

[0339] This embodiment can be appropriately combined with other embodiments shown in this specification.

[0340] (Embodiment 8) This embodiment describes a light-emitting device using a light-emitting device described in any one of Embodiments 1 to 6.

[0341] In this embodiment, a light-emitting device manufactured using a light-emitting device described in any one of Embodiments 1 to 6 will be described with reference to Figure 4. Figure 4A is a top view showing the light-emitting device, and Figure 4B is a cross-sectional view obtained by cutting Figure 4A along lines AB and CD. This light-emitting device includes a drive circuit section (source line drive circuit 601), a pixel section 602, and a drive circuit section (gate line drive circuit 603), all indicated by dotted lines, to control the light emission of the light-emitting device. Furthermore, 604 is a sealing substrate, and 605 is a sealing material, with the area enclosed by the sealing material 605 being a space 607.

[0342] The routing wiring 608 is for transmitting signals input to the source line drive circuit 601 and the gate line drive circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from the FPC (flexible printed circuit) 609, which serves as an external input terminal. Although only the FPC is shown in this illustration, a printed circuit board (PWB) may be attached to this FPC. In this specification, the light-emitting device includes not only the light-emitting device itself, but also the state in which the FPC or PWB is attached to it.

[0343] Next, the cross-sectional structure will be explained using Figure 4B. A drive circuit section and a pixel section are formed on the element substrate 610, and here, the source line drive circuit 601, which is the drive circuit section, and one pixel in the pixel section 602 are shown.

[0344] The element substrate 610 may be manufactured using a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or other materials, as well as a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, or acrylic resin.

[0345] The structure of the transistor used in the pixel or driving circuit is not particularly limited. For example, it may be an inverse staggered transistor or a staggered transistor. It may also be a top-gate or bottom-gate transistor. The semiconductor material used for the transistor is not particularly limited; for example, silicon, germanium, silicon carbide, gallium nitride, etc., can be used. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn metal oxide, may be used.

[0346] 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 having a crystalline region in part) may be used. Using a crystalline semiconductor is preferable because it can suppress the degradation of transistor characteristics.

[0347] Here, it is preferable to use oxide semiconductors for semiconductor devices such as transistors used in the pixels or driving circuits described above, as well as transistors used in touch sensors and the like, which will be described later. In particular, it is preferable to use oxide semiconductors with a wider bandgap than silicon. By using oxide semiconductors with a wider bandgap than silicon, the current in the off state of the transistor can be reduced.

[0348] The above oxide semiconductor preferably contains at least indium (In) or zinc (Zn). More preferably, it is an oxide semiconductor containing an oxide represented as an In-M-Zn oxide (where M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0349] In particular, it is preferable to use an oxide semiconductor film as the semiconductor layer, which has multiple crystalline portions, the c-axis of which is oriented perpendicular to the surface on which the semiconductor layer is formed or to the upper surface of the semiconductor layer, and which does not have grain boundaries between adjacent crystalline portions.

[0350] By using such materials as semiconductor layers, fluctuations in electrical properties can be suppressed, enabling the realization of highly reliable transistors.

[0351] Furthermore, due to its low off-current, the transistor having the aforementioned semiconductor layer can retain the charge stored in the capacitor via the transistor for a long period of time. By applying such transistors to pixels, it becomes possible to maintain the gradation of the image displayed in each display area while simultaneously stopping the drive circuit. As a result, electronic devices with extremely reduced power consumption can be realized.

[0352] It is preferable to provide an undercoat to stabilize the characteristics of the transistor. As the undercoat, an inorganic insulating film such as a silicon oxide film, silicon nitride film, silicon oxynitride film, or silicon nitride film can be used and fabricated as a single layer or in layers. The undercoat can be formed using sputtering, CVD (Chemical Vapor Deposition) (plasma CVD, thermal CVD, MOCVD (Metal Organic CVD), etc.), ALD (Atomic Layer Deposition), coating, printing, etc. Note that the undercoat may be omitted if not necessary.

[0353] Note that FET623 is one of the transistors formed in the source line drive circuit 601. The drive circuit can be formed using various CMOS, PMOS, or NMOS circuits. In this embodiment, a driver-integrated type with the drive circuit formed on the substrate is shown, but this is not necessarily required, and the drive circuit can be formed externally instead of on the substrate.

[0354] Furthermore, although the pixel section 602 is formed by a plurality of pixels including a switching FET 611 and a current control FET 612 and a first electrode 613 electrically connected to its drain, it is not limited to this, and the pixel section may be a combination of three or more FETs and a capacitive element.

[0355] Furthermore, an insulator 614 is formed to cover the end of the first electrode 613. This can be formed by using a positive-type photosensitive acrylic resin film.

[0356] Furthermore, in order to ensure good coverage of the EL layer and the like that will be formed later, a curved surface with curvature is formed at the upper or lower end of the insulator 614. For example, when a positive-type photosensitive acrylic resin is used as the material for the insulator 614, it is preferable to have a curved surface with a radius of curvature (0.2 μm or more and 3 μm or less) only at the upper end of the insulator 614. In addition, either a negative-type photosensitive resin or a positive-type photosensitive resin can be used as the insulator 614.

[0357] An EL layer 616 and a second electrode 617 are formed on the first electrode 613, respectively. Here, it is desirable to use a material with a large work function for the first electrode 613 which functions as an anode. For example, in addition to single-layer films such as ITO film, silicon-containing indium tin oxide film, indium oxide film containing 2 wt% to 20 wt% zinc oxide, titanium nitride film, chromium film, tungsten film, Zn film, and Pt film, a laminate of titanium nitride film and a film mainly composed of aluminum, or a three-layer structure of titanium nitride film, a film mainly composed of aluminum, and titanium nitride film can be used. Furthermore, a laminated structure has low resistance as wiring, good ohmic contact can be obtained, and it can function as an anode.

[0358] Furthermore, the EL layer 616 is formed by various methods such as vapor deposition using a vapor deposition mask, inkjet printing, and spin coating. The EL layer 616 includes the configuration described in any one of Embodiments 1 to 6. Other materials constituting the EL layer 616 may be low molecular weight compounds or high molecular weight compounds (including oligomers and dendrimers).

[0359] Furthermore, it is preferable to use a material with a small work function (such as Al, Mg, Li, Ca, or alloys or compounds thereof (MgAg, MgIn, AlLi, etc.)) for the second electrode 617, which is formed on the EL layer 616 and functions as a cathode. When light generated in the EL layer 616 is transmitted through the second electrode 617, it is preferable to use a laminate of a thin metal film and a transparent conductive film (such as ITO, indium oxide containing 2 wt% to 20 wt% zinc oxide, indium tin oxide containing silicon, zinc oxide (ZnO), etc.) as the second electrode 617.

[0360] The first electrode 613, the EL layer 616, and the second electrode 617 form the light-emitting device 618. This light-emitting device is the light-emitting device described in any one of Embodiments 1 to 6. Although the pixel portion is made up of multiple light-emitting devices, the light-emitting device in this embodiment may contain a mixture of light-emitting devices described in any one of Embodiments 1 to 6 and light-emitting devices having other configurations.

[0361] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with the sealing material 605, the light-emitting device 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealing material 605. The space 607 is filled with a filler material, which may be an inert gas (such as nitrogen or argon) or a sealing material. A recess is formed in the sealing substrate, and a desiccant is placed therein to suppress deterioration due to the effects of moisture, which is a preferred configuration.

[0362] Furthermore, it is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as impermeable to moisture or oxygen as possible. In addition to glass substrates or quartz substrates, plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, or acrylic resin can be used as the material for the sealing substrate 604.

[0363] Although not shown in Figure 4, a protective film may be provided on the second electrode. The protective film may be formed of an organic resin film or an inorganic insulating film. Alternatively, the protective film may be formed to cover the exposed portion of the sealing material 605. Furthermore, the protective film can be provided to cover the surface and sides of the pair of substrates, the sealing layer, the insulating layer, and other exposed sides.

[0364] The protective film can be made of a material that is impermeable to impurities such as water. Therefore, it is possible to effectively suppress the diffusion of impurities such as water from the outside to the inside.

[0365] Materials that constitute the protective film can include oxides, nitrides, fluorides, sulfides, ternary compounds, metals, or polymers. For example, materials containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, or indium oxide, or materials containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, nitrides containing titanium and aluminum, oxides containing titanium and aluminum, oxides containing aluminum and zinc, sulfides containing manganese and zinc, sulfides containing cerium and strontium, oxides containing erbium and aluminum, oxides containing yttrium and zirconium, etc.

[0366] It is preferable to form the protective film using a film deposition method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using the ALD method for the protective film. By using the ALD method, it is possible to form a dense protective film with reduced defects such as cracks or pinholes, or a protective film with a uniform thickness. Furthermore, it is possible to reduce the damage inflicted on the processed workpiece when forming the protective film.

[0367] For example, by forming a protective film using the ALD method, a uniform and defect-free protective film can be formed on surfaces with complex uneven shapes, or on the top, sides, and back surfaces of a touch panel.

[0368] As described above, a light-emitting device can be obtained using the light-emitting device described in any one of Embodiments 1 to 6.

[0369] Since the light-emitting device in this embodiment uses the light-emitting device described in any one of Embodiments 1 to 6, a light-emitting device with good characteristics can be obtained. Specifically, since the light-emitting device described in any one of Embodiments 1 to 6 has good luminous efficiency, it is possible to make a light-emitting device with low power consumption.

[0370] Figure 5 shows an example of a light-emitting device that is made full-color by forming a light-emitting device that emits white light and providing a colored layer (color filter), etc. Figure 5A shows the substrate 1001, the underlayer insulating film 1002, the gate insulating film 1003, the gate electrodes 1006, 1007, 1008, the first interlayer insulating film 1020, the second interlayer insulating film 1021, the peripheral part 1042, the pixel part 1040, the drive circuit part 1041, the first electrodes 1024W, 1024R, 1024G, 1024B of the light-emitting device, the partition wall 1025, the EL layer 1028, the second electrode 1029 of the light-emitting device, the sealing substrate 1031, the sealing material 1032, etc.

[0371] In Figure 5A, the colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) are provided on a transparent substrate 1033. A black matrix 1035 may also be provided. The transparent substrate 1033 on which the colored layers and black matrix are provided is aligned and fixed to the substrate 1001. The colored layers and black matrix 1035 are covered with an overcoat layer 1036. In Figure 5A, there is an emissive layer that emits light to the outside without passing through the colored layers, and an emissive layer that emits light to the outside by passing through each colored layer. Light that does not pass through the colored layers is white, and light that passes through the colored layers is red, green, and blue, so an image can be represented with four colored pixels.

[0372] Figure 5B shows an example in which colored layers (red colored layer 1034R, green colored layer 1034G, and blue colored layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. Thus, the colored layers may also be provided between the substrate 1001 and the encapsulating substrate 1031.

[0373] Furthermore, although the light-emitting device described above is a bottom-emission type device that extracts light from the substrate 1001 on which the FET is formed, it may also be a top-emission type device that extracts light from the sealing substrate 1031. A cross-sectional view of the top-emission type light-emitting device is shown in Figure 6. In this case, the substrate 1001 can be a substrate that does not transmit light. The process is the same as for the bottom-emission type light-emitting device until the connecting electrode that connects the FET and the anode of the light-emitting device is fabricated. After that, a third interlayer insulating film 1037 is formed covering the electrode 1022. This insulating film may also play a planarization role. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film, as well as other known materials.

[0374] The first electrodes 1024W, 1024R, 1024G, and 1024B of the light-emitting device are designated as anodes here, but they may also be cathodes. Furthermore, in the case of a top-emission type light-emitting device as shown in Figure 6, it is preferable that the first electrodes be reflective electrodes. The configuration of the EL layer 1028 shall be as described as unit 103 in any one of Embodiments 1 to 6, and shall be an element structure that produces white light emission.

[0375] In the top emission structure shown in Figure 6, sealing can be performed with a sealing substrate 1031 having colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B). A black matrix 1035 may be provided on the sealing substrate 1031 so as to be located between pixels. The colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) or the black matrix may be covered with an overcoat layer 1036. The sealing substrate 1031 should be a translucent substrate. In addition, although an example of full-color display using four colors, red, green, blue, and white, is shown here, it is not particularly limited, and full-color display may be performed using four colors, red, yellow, green, and blue, or three colors, red, green, and blue.

[0376] In top-emission type light-emitting devices, a microcavity structure can be suitably applied. A light-emitting device having a microcavity structure is obtained by using a reflective electrode as the first electrode and a semi-transparent / semi-reflective electrode as the second electrode. There is at least an EL layer between the reflective electrode and the semi-transparent / semi-reflective electrode, and there is at least a light-emitting layer that forms a light-emitting region.

[0377] The reflective electrode has a visible light reflectance of 40% to 100%, preferably 70% to 100%, and its resistivity is 1 × 10⁻⁶. -2 The film thickness is assumed to be Ωcm or less. Furthermore, the semi-transparent / semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and its resistivity is 1 × 10⁻⁶. -2 Assume the membrane is less than Ωcm in diameter.

[0378] The light emitted from the light-emitting layer contained in the EL layer is reflected by the reflective electrode and the semi-transparent / semi-reflective electrode, causing resonance.

[0379] This light-emitting device allows you to change the optical distance between the reflective electrode and the semi-transparent / semi-reflective electrode by changing the thickness of the transparent conductive film or the aforementioned composite material, carrier transport material, etc. This makes it possible to strengthen light of resonant wavelengths and attenuate light of non-resonant wavelengths between the reflective electrode and the semi-transparent / semi-reflective electrode.

[0380] Furthermore, since the light reflected back by the reflective electrode (first reflected light) interferes significantly with the light that directly enters the semi-transparent / semi-reflective electrode from the light-emitting layer (first incident light), it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number greater than or equal to 1, and λ is the wavelength of the light emission to be amplified). By adjusting this optical distance, the phases of the first reflected light and the first incident light can be aligned, and the light emission from the light-emitting layer can be further amplified.

[0381] In the above configuration, the EL layer may have a structure with multiple light-emitting layers or a structure with a single light-emitting layer. For example, it may be applied to a configuration in which multiple EL layers are provided in a single light-emitting device with a charge generation layer in between, and one or more light-emitting layers are formed in each EL layer, in combination with the tandem light-emitting device configuration described above.

[0382] By incorporating a microcavity structure, it becomes possible to enhance the emission intensity in the front direction at specific wavelengths, thereby reducing power consumption. Furthermore, in the case of a light-emitting device that displays images using four sub-pixels of red, yellow, green, and blue, in addition to the brightness enhancement effect of yellow emission, a microcavity structure tailored to the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with excellent characteristics.

[0383] Since the light-emitting device in this embodiment uses the light-emitting device described in any one of Embodiments 1 to 6, a light-emitting device with good characteristics can be obtained. Specifically, since the light-emitting device described in any one of Embodiments 1 to 6 has good luminous efficiency, it is possible to make a light-emitting device with low power consumption.

[0384] Up to this point, we have described an active matrix type light-emitting device, but from here on we will describe a passive matrix type light-emitting device. Figure 7 shows a passive matrix type light-emitting device manufactured by applying the present invention. Figure 7A is a perspective view of the light-emitting device, and Figure 7B is a cross-sectional view of Figure 7A cut along the X and Y lines. In Figure 7, an EL layer 955 is provided on the substrate 951 between electrodes 952 and 956. The ends of electrodes 952 are covered with an insulating layer 953. A partition layer 954 is provided on the insulating layer 953. The side walls of the partition layer 954 have a slope such that the distance between one side wall and the other side wall narrows as they get closer to the substrate surface. In other words, the cross-section of the partition layer 954 in the short-side direction is trapezoidal, with the bottom side (facing the same direction as the surface direction of the insulating layer 953 and in contact with the insulating layer 953) being shorter than the top side (facing the same direction as the surface direction of the insulating layer 953 and not in contact with the insulating layer 953). By providing the partition layer 954 in this way, it is possible to prevent malfunctions of the light-emitting device caused by static electricity, etc. Furthermore, even in a passive matrix type light-emitting device, if the light-emitting device described in any one of Embodiments 1 to 6 is used, it is possible to make a light-emitting device with good reliability or a light-emitting device with low power consumption.

[0385] As described above, the light-emitting device is suitable for use as a display device for representing images because it is possible to control each of the numerous minute light-emitting devices arranged in a matrix.

[0386] Furthermore, this embodiment can be freely combined with other embodiments.

[0387] (Embodiment 9) In this embodiment, an example of using the light-emitting device described in any one of Embodiments 1 to 6 as an illumination device will be described with reference to Figure 8. Figure 8B is a top view of the illumination device, and Figure 8A is a cross-sectional view of ef in Figure 8B.

[0388] 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 any one of Embodiments 1 to 6. When light is extracted from the first electrode 401 side, the first electrode 401 is formed from a translucent material.

[0389] A pad 412 for supplying voltage to the second electrode 404 is formed on the substrate 400.

[0390] An EL layer 403 is formed on the first electrode 401. The EL layer 403 corresponds to the configuration of unit 103 in any one of Embodiments 1 to 6, or to a configuration combining unit 103(12) and the intermediate layer 106. Please refer to the relevant description for details on these configurations.

[0391] A second electrode 404 is formed by covering the EL layer 403. The second electrode 404 corresponds to the second electrode 102 in any one of Embodiments 1 to 6. 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.

[0392] 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.

[0393] 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 and 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 8B), which allows for the adsorption of moisture and leads to improved reliability.

[0394] 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.

[0395] As described above, the lighting device described in this embodiment uses the light-emitting device described in any one of Embodiments 1 to 6 as the EL element, and can be a lighting device with low power consumption.

[0396] (Embodiment 10) This embodiment describes an example of an electronic device that includes a light-emitting device described in any one of Embodiments 1 to 6 as part of it. The light-emitting device described in any one of Embodiments 1 to 6 has good luminous efficiency and is a light-emitting device with low power consumption. As a result, the electronic device described in this embodiment can be an electronic device having a light-emitting part with low power consumption.

[0397] Examples of electronic devices to which the above-mentioned light-emitting devices are applied include television equipment (also called televisions or television receivers), monitors for computers, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game consoles, personal digital assistants, sound playback devices, and large game machines such as pachinko machines. Specific examples of these electronic devices are shown below.

[0398] Figure 9A shows an example of a television system. The television system has a display unit 7103 incorporated into a housing 7101. This figure also shows a configuration in which the housing 7101 is supported by a stand 7105. The display unit 7103 is capable of displaying images, and the display unit 7103 is configured by arranging the light-emitting devices described in any one of Embodiments 1 to 6 in a matrix.

[0399] The television system can be operated using the operation switches on the housing 7101 or a separate remote control unit 7110. The operation keys 7109 on the remote control unit 7110 allow for channel or volume control, and the image displayed on the display unit 7103 can be controlled. Alternatively, the remote control unit 7110 may be configured to include a display unit 7107 that displays information output from the remote control unit 7110.

[0400] The television system shall consist of a receiver or modem. The receiver will be able to receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it will also be possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0401] Figure 9B1 shows a computer, which includes a main unit 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, etc. This computer is manufactured by arranging the light-emitting devices described in any one of Embodiments 1 to 6 in a matrix and using them for the display unit 7203. The computer in Figure 9B1 may also take the form shown in Figure 9B2. The computer in Figure 9B2 has a second display unit 7210 instead of the keyboard 7204 and pointing device 7206. The second display unit 7210 is a touch panel, and input can be performed by operating the input display shown on the second display unit 7210 with a finger or a dedicated pen. In addition to the input display, the second display unit 7210 can also display other images. The display unit 7203 may also be a touch panel. The two screens are connected by a hinge, which prevents problems such as scratching or damaging the screens when storing or transporting the device.

[0402] Figure 9C shows an example of a mobile terminal. The mobile terminal includes a display unit 7402 incorporated into a housing 7401, as well as operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. The mobile terminal has a display unit 7402 made by arranging the light-emitting devices described in any one of Embodiments 1 to 6 in a matrix.

[0403] The mobile terminal shown in Figure 9C can also be configured to allow information input by touching the display unit 7402 with a finger or other object. In this case, operations such as making a phone call or composing an email can be performed by touching the display unit 7402 with a finger or other object.

[0404] The display unit 7402 has three main modes. The first is a display mode that primarily displays images, the second is an input mode that primarily inputs information such as text, and the third is a display + input mode that combines the display mode and the input mode.

[0405] For example, when making a phone call or composing an email, the display unit 7402 should be set to a text input mode, which primarily focuses on text input, and the user should input the characters displayed on the screen. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display unit 7402.

[0406] Furthermore, by providing a detection device with a tilt sensor such as a gyroscope or accelerometer inside the mobile terminal, the orientation of the mobile terminal (portrait or landscape) can be determined, and the screen display of the display unit 7402 can be automatically switched accordingly.

[0407] Furthermore, the screen mode can be switched by touching the display unit 7402 or by operating the operation button 7403 on the housing 7401. It is also possible to switch modes depending on the type of image displayed on the display unit 7402. For example, if the image signal displayed on the display unit is video data, it can be switched to display mode; if it is text data, it can be switched to input mode.

[0408] Furthermore, in input mode, the system may detect a signal detected by the optical sensor of the display unit 7402 and, if there is no input via touch operation on the display unit 7402 for a certain period of time, control may be made to switch the screen mode from input mode to display mode.

[0409] The display unit 7402 can also function as an image sensor. For example, by touching the display unit 7402 with the palm or finger, palm prints, fingerprints, etc., can be captured to perform user authentication. Furthermore, by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light in the display unit, finger veins, palm veins, etc., can also be captured.

[0410] Figure 10A is a schematic diagram showing an example of a cleaning robot.

[0411] The cleaning robot 5100 has a display 5101 on its top surface, multiple cameras 5102 on its sides, a brush 5103, and control buttons 5104. Although not shown in the illustration, the cleaning robot 5100 also has wheels, a suction port, etc. on its underside. The cleaning robot 5100 is also equipped with various sensors, including an infrared sensor, an ultrasonic sensor, an accelerometer, a piezoelectric sensor, a light sensor, and a gyroscope. Furthermore, the cleaning robot 5100 is equipped with a means of wireless communication.

[0412] The cleaning robot 5100 is self-propelled, can detect dirt 5120, and can suck up the dirt through a suction port located on its underside.

[0413] Furthermore, the cleaning robot 5100 can analyze images captured by the camera 5102 to determine the presence or absence of obstacles such as walls, furniture, or steps. If the image analysis detects objects that could become entangled in the brush 5103, such as wiring, it can stop the brush 5103 from rotating.

[0414] The display 5101 can display information such as the remaining battery level or the amount of dirt collected. The path taken by the cleaning robot 5100 may also be displayed on the display 5101. Alternatively, the display 5101 may be a touch panel, and operation buttons 5104 may be provided on the display 5101.

[0415] The cleaning robot 5100 can communicate with a portable electronic device 5140, such as a smartphone. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can check the status of the room even when they are away from home. In addition, the display on the display 5101 can be checked on a portable electronic device such as a smartphone.

[0416] A light-emitting device according to one aspect of the present invention can be used in a display 5101.

[0417] The robot 2100 shown in Figure 10B includes a computing unit 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a movement mechanism 2108.

[0418] The microphone 2102 has the function of detecting the user's voice and ambient sounds. The speaker 2104 has the function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and speaker 2104.

[0419] The display 2105 has the function of displaying various types of information. The robot 2100 can display the information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may also be a detachable information terminal, and by installing it in a fixed position on the robot 2100, charging and data transfer can be made possible.

[0420] The upper camera 2103 and the lower camera 2106 have the function of imaging the area around the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of obstacles in the direction of travel when the robot 2100 moves forward using the movement mechanism 2108. The robot 2100 can recognize its surrounding environment and move safely using the upper camera 2103, the lower camera 2106 and the obstacle sensor 2107. The light-emitting device according to one aspect of the present invention can be used in the display 2105.

[0421] Figure 10C shows an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, operation keys (including a power switch or operation switch), connection terminals 5006, a sensor 5007 (including functions for measuring force, displacement, position, velocity, acceleration, angular velocity, rotational speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared radiation), a microphone 5008, a display unit 5002, a support unit 5012, an earphone 5013, etc.

[0422] A light-emitting device according to one aspect of the present invention can be used in the display unit 5001 and the display unit 5002.

[0423] Figure 11 shows an example in which the light-emitting device described in any one of Embodiments 1 to 6 is used in a desk lamp, which is a lighting device. The desk lamp shown in Figure 11 has a housing 2001 and a light source 2002, and the lighting device described in Embodiment 9 may be used as the light source 2002.

[0424] Figure 12 shows an example of using the light-emitting device described in any one of Embodiments 1 to 6 as an indoor lighting device 3001. Since the light-emitting device described in any one of Embodiments 1 to 6 is a light-emitting device with high luminous efficiency, it can be used as a lighting device with low power consumption. Furthermore, since the light-emitting device described in any one of Embodiments 1 to 6 can be made to cover a large area, it can be used as a large-area lighting device. In addition, since the light-emitting device described in any one of Embodiments 1 to 6 is thin, it can be used as a thin lighting device.

[0425] The light-emitting device described in any one of Embodiments 1 to 6 can also be mounted on the windshield or dashboard of an automobile. Figure 13 shows one embodiment in which the light-emitting device described in any one of Embodiments 1 to 6 is used on the windshield or dashboard of an automobile. Display areas 5200 to 5203 are display areas provided using the light-emitting device described in any one of Embodiments 1 to 6.

[0426] Display area 5200 and display area 5201 are display devices equipped with a light-emitting device according to any one of Embodiments 1 to 6, which is installed on the windshield of an automobile. The light-emitting device according to any one of Embodiments 1 to 6 can be made into a so-called see-through display device, where the opposite side is visible, by making the first electrode and the second electrode from translucent electrodes. If the display is in a see-through state, it can be installed on the windshield of an automobile without obstructing the view. When providing transistors for driving, it is preferable to use translucent transistors such as organic transistors made of organic semiconductor materials or transistors using oxide semiconductors.

[0427] The display area 5202 is a display device equipped with a light-emitting device described in any one of Embodiments 1 to 6, which is provided on the pillar. By displaying images from an imaging means provided on the vehicle body on the display area 5202, the field of view obstructed by the pillar can be supplemented. Similarly, the display area 5203 provided on the dashboard can compensate for blind spots and enhance safety by displaying images from an imaging means provided on the outside of the vehicle, which is obstructed by the vehicle body. By displaying images to supplement the parts that are not visible, safety checks can be performed more naturally and without discomfort.

[0428] Display area 5203 can also provide various information by displaying navigation information, speedometer or RPM, mileage, fuel gauge, gear status, air conditioning settings, etc. The display items or layout can be changed as needed to suit the user's preferences. This information can also be provided in display areas 5200 to 5202. Furthermore, display areas 5200 to 5203 can also be used as illumination devices.

[0429] Figures 14A to 14C also show a foldable portable information terminal 9310. Figure 14A shows the portable information terminal 9310 in its unfolded state. Figure 14B shows the portable information terminal 9310 in an intermediate state, either unfolded or folded. Figure 14C shows the portable information terminal 9310 in its folded state. The portable information terminal 9310 offers excellent portability in its folded state and excellent readability of the display due to its seamless, wide display area in its unfolded state.

[0430] The functional panel 9311 is supported by three housings 9315 connected by a hinge 9313. The functional panel 9311 may also be a touch panel (input / output device) equipped with a touch sensor (input device). Furthermore, the functional panel 9311 can be reversibly transformed from an unfolded state to a folded state of the portable information terminal 9310 by bending the two housings 9315 via the hinge 9313. A light-emitting device according to one aspect of the present invention can be used in the functional panel 9311.

[0431] Furthermore, the configuration shown in this embodiment can be used by appropriately combining the configurations shown in Embodiments 1 to 6.

[0432] As described above, the scope of application of the light-emitting device equipped with the light-emitting device described in any one of Embodiments 1 to 6 is extremely broad, and this light-emitting device can be applied to electronic devices in all fields. By using the light-emitting device described in any one of Embodiments 1 to 6, it is possible to obtain electronic devices with low power consumption.

[0433] This embodiment can be appropriately combined with other embodiments shown in this specification. [Examples]

[0434] In this embodiment, one embodiment of the present invention, described with reference to Figures 15 to 27, will be explained.

[0435] Figure 15 is a diagram illustrating the configuration of a light-emitting device according to one embodiment of the present invention. Figure 15A is a diagram illustrating the configuration of light-emitting device 1, Figure 15B is a diagram illustrating the configuration of light-emitting device 2, and Figure 15C is a diagram illustrating a part of the configuration of the light-emitting device.

[0436] Figure 16 illustrates the current density-luminance characteristics of light-emitting device 1 and comparative light-emitting device 1.

[0437] Figure 17 illustrates the luminance-current efficiency characteristics of light-emitting device 1 and comparative light-emitting device 1.

[0438] Figure 18 illustrates the voltage-luminance characteristics of light-emitting device 1 and comparison light-emitting device 1.

[0439] Figure 19 illustrates the voltage-current characteristics of light-emitting device 1 and comparison light-emitting device 1.

[0440] Figure 20 illustrates the luminance-blue index characteristics of light-emitting device 1 and comparison light-emitting device 1.

[0441] Figure 21 shows the light-emitting device 1 and the comparative light-emitting device 1 at 1000 cd / m². 2 This diagram illustrates the emission spectrum when the light source is emitted at a specific brightness level.

[0442] <Light-emitting device 1> The light-emitting device 1 described in this embodiment has the function of emitting light EL1, and includes an electrode 101, an electrode 102, and a unit 103 (see Figure 15A).

[0443] Optical EL1 has a spectrum φ1, which has a maximum peak at a wavelength λ1 nm.

[0444] Electrode 102 has a region that overlaps with electrode 101. Unit 103 has a region sandwiched between electrode 101 and electrode 102, and unit 103 comprises layers 111, 112, and 113.

[0445] Layer 111 comprises a region sandwiched between layers 112 and 113, and layer 111 contains a light-emitting material.

[0446] Layer 112 comprises layer 112A and layer 112B. Layer 112B includes a region sandwiched between layer 112A and layer 111, and layer 112B is in contact with layer 112A.

[0447] Layer 112A has a refractive index of 2.02 for light with a wavelength of 460 nm.

[0448] Layer 112B has a refractive index of 1.69 for light with a wavelength of 460 nm, and the refractive index of 1.69 is in the range of 1.4 to 1.75, which is smaller than the refractive index of 2.02.

[0449] Furthermore, a refractive index of 1.69 is 0.33 different from a refractive index of 2.02.

[0450] Furthermore, the light-emitting device 1 fabricated in this embodiment has a layer 111 with a thickness of 25 nm, and a layer 112A is separated from layer 111 by a distance of 45 nm.

[0451] When the distance d is 45 nm, the thickness t is 25 nm, the wavelength λ is 460 nm, and the refractive index n² is 1.69, the value of (d + t / 2) × n² is 97.125 nm. Also, the value of 0.5 × 0.25 × 460 nm is 57.5 nm, and the value of 1.5 × 0.25 × 460 nm is 172.5 nm. That is, 97.125 nm is in the range of 57.5 nm to 172.5 nm.

[0452] Configuration of Light-Emitting Device 1 Table 1 shows the configuration of the light-emitting device 1. The structural formulas of the materials used in the light-emitting device described in this embodiment are shown below.

[0453] [Table 1]

[0454] [ka]

[0455] 《Method for fabricating light-emitting device 1》 The light-emitting device 1 described in this embodiment was fabricated using a method comprising the following steps.

[0456] [Step 1] In the first step, a reflective film REF was formed. Specifically, it was formed by sputtering using silver (Ag) as the target.

[0457] The reflective film REF contains Ag and has a thickness of 100 nm.

[0458] [Step 2] In the second step, a conductive film TCF was formed on the reflective film REF. Specifically, it was formed by sputtering using indium tin oxide (ITSO) containing silicon or silicon oxide as the target.

[0459] The conductive film TCF contains ITSO and has a thickness of 10 nm and 4 mm2 It has an area of ​​(2mm x 2mm).

[0460] Next, the substrate on which the electrodes 101 were formed was washed with water, fired at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber within the vacuum deposition apparatus. After that, the substrate was allowed to cool for about 30 minutes.

[0461] [Step 3] In the third step, a layer 104 was formed on the electrode 101. Specifically, the material was co-deposited using a resistance heating method.

[0462] Layer 104 contains 4,4'-bis(dibenzothiophen-4-yl)-4''-(9-phenyl-9H-carbazole-2-yl)triphenylamine (abbreviated as PCBDBtBB-02) and an electron acceptor material (abbreviated as OCHD-001) in a ratio of PCBDBtBB-02:OCHD-001 = 1:0.1 (by weight), and has a thickness of 10 nm.

[0463] [Step 4] In the fourth step, layer 112A was formed on layer 104. Specifically, material CTM1 was deposited using the resistance heating method.

[0464] Layer 112A contains PCBDBtBB-02 and has a thickness of 70 nm. Furthermore, PCBDBtBB-02 has a refractive index of 2.02 for light with a wavelength of 460 nm.

[0465] [Step 5] In the fifth step, layer 112B was formed on layer 112A. Specifically, material CTM2 was deposited using the resistance heating method.

[0466] Furthermore, the material CTM2 used was N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as mmtBumTPoFBi-02). Layer 112B contains mmtBumTPoFBi-02 and has a thickness of 35 nm. In addition, mmtBumTPoFBi-02 has a refractive index of 1.69 for light with a wavelength of 460 nm.

[0467] [Step 6] In the sixth step, layer 112C was formed on layer 112B. Specifically, the material was deposited using the resistance heating method.

[0468] Layer 112C includes PCBDBtBB-02 and has a thickness of 10 nm.

[0469] [Step 7] In the seventh step, layer 111 was formed on layer 112C. Specifically, the material was co-deposited using the resistance heating method.

[0470] Layer 111 contains 2-(10-phenyl-9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviated as Bnf(II)PhA) and 3,10-bis[N-(9-phenyl-9H-carbazole-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviated as 3,10PCA2Nbf(IV)-02) in a weight ratio of Bnf(II)PhA:3,10PCA2Nbf(IV)-02 = 1:0.015 and has a thickness of 25 nm.

[0471] [Step 8] In the eighth step, layer 113A was formed on layer 111. Specifically, the material was deposited using the resistance heating method.

[0472] Layer 113A contains 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mFBPTzn) and has a thickness of 10 nm.

[0473] [Step 9] In the ninth step, layer 113B was formed on layer 113A. Specifically, the material was co-deposited using the resistance heating method.

[0474] Layer 113B contains 2-[3-(2,6-dimethyl-3-pyridinyl)-5-(9-phenantrenyl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviated as mPn-mDMePyPTzn) and 8-hydroxyquinolinatolithium (abbreviated as Liq) in a ratio of mPn-mDMePyPTzn:Liq = 1:1 (by weight), and has a thickness of 20 nm.

[0475] [Step 10] In the tenth step, layer 105 was formed on layer 113B. Specifically, the material was deposited using the resistance heating method.

[0476] Layer 105 contains LiF and has a thickness of 1 nm.

[0477] [Step 11] In the 11th step, an electrode 102 was formed on layer 105. Specifically, the material was co-deposited using a resistance heating method.

[0478] The electrode 102 contains Ag and Mg in an Ag:Mg = 10:1 (volume ratio) and has a thickness of 15 nm.

[0479] [Step 12] In the twelfth step, a layer CAP was formed on electrode 102. Specifically, the material was deposited using a resistance heating method.

[0480] The layer CAP contains 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene)) (abbreviated as DBT3P-II) and has a thickness of 70 nm.

[0481] Operating characteristics of the light-emitting device 1 When power was supplied, the light-emitting device 1 emitted light EL1 (see Figure 15A). The operating characteristics of the light-emitting device 1 were measured (see Figures 16 to 21). The measurements were performed at room temperature using a spectroradiometer (Topcon UR-UL1R).

[0482] Light-emitting device 1 has a brightness of 1000 cd / m². 2 Table 2 shows the main initial characteristics when the device is emitting light at a certain level. The initial characteristics of comparative light-emitting device 1 are also listed in Table 2, and its configuration will be described later.

[0483] [Table 2]

[0484] The Blue Index (BI) is a value obtained by dividing the current efficiency (cd / A) by the y-chromaticity, and is one of the indicators that represent the emission characteristics of blue light emission. Blue light emission tends to have higher color purity as the y-chromaticity decreases. High-color-purity blue light emission can express a wide range of blue colors even with a small luminance component, and by using high-color-purity blue light emission, the required luminance to express blue decreases, resulting in a reduction in power consumption. For this reason, the BI, which takes into account the y-chromaticity, one of the indicators of blue purity, is suitably used as a means of representing the efficiency of blue light emission, and it can be said that light-emitting devices with a higher BI are more efficient as blue light-emitting devices used in displays.

[0485] Light-emitting device 1 was found to exhibit excellent characteristics. For example, light-emitting device 1 was able to achieve the same brightness as comparative light-emitting device 1 at the same driving voltage and with a lower current density than comparative light-emitting device 1 (see Table 2). Alternatively, light-emitting device 1 was able to achieve the same brightness with lower power consumption than comparative light-emitting device 1. Furthermore, light-emitting device 1 showed higher current efficiency than comparative light-emitting device 1 (see Table 2 and Figure 17). In addition, light-emitting device 1 showed a blue index approximately 1.07 times higher than comparative light-emitting device 1 (see Table 2 and Figure 20). As a result, a novel light-emitting device with superior convenience, usefulness, and reliability was provided.

[0486] (Reference example 1) The comparative light-emitting device 1 described in this embodiment differs from light-emitting device 1 in the thickness of layer 112B and the material CTM2 used for layer 112B. Specifically, it differs from light-emitting device 1 in that PCBDBtBB-02 is used for material CTM2 instead of mmtBumTPoFBi-02. In other words, layers 112A, 112B, and 112C were formed in a single region using the same material for materials CTM1 and CTM2.

[0487] 《Method for fabricating comparative light-emitting device 1》 A comparative light-emitting device 1 was fabricated using a method comprising the following steps.

[0488] Note that the fabrication method for comparative light-emitting device 1 differs from that of light-emitting device 1 in that, in the step of forming layer 112B, PCBDBtBB-02 is used instead of mmtBumTPoFBi-02, and a thickness of 30 nm is used instead of 35 nm. In other words, layers 112A, 112B, and 112C are formed using PCBDBtBB-02, and the total thickness is 110 nm. Here, the differences will be explained in detail, and the above explanation will be used as a reference for parts where the same method is used.

[0489] [Step 5] In the fifth step, layer 112B was formed on layer 112A. Specifically, the material was deposited using the resistance heating method.

[0490] Layer 112B includes PCBDBtBB-02 and has a thickness of 30 nm.

[0491] Table 2 shows the main initial characteristics of comparative light-emitting device 1. [Examples]

[0492] In this embodiment, a light-emitting device 2 according to one aspect of the present invention, which was fabricated, will be described with reference to Figures 22 to 27.

[0493] Figure 22 illustrates the current density-luminance characteristics of the light-emitting device 2.

[0494] Figure 23 illustrates the luminance-current efficiency characteristics of the light-emitting device 2.

[0495] Figure 24 illustrates the voltage-luminance characteristics of the light-emitting device 2.

[0496] Figure 25 illustrates the voltage-current characteristics of the light-emitting device 2.

[0497] Figure 26 illustrates the luminance-external quantum efficiency characteristics of light-emitting device 2. The external quantum efficiency was calculated from the luminance, assuming that the light distribution characteristics of the light-emitting device are Lambertsian.

[0498] Figure 27 shows the light-emitting device 2 at 1000 cd / m². 2 This diagram illustrates the emission spectrum when the light source is emitted at a specific brightness level.

[0499] <Light-emitting device 2> The light-emitting device 2 described in this embodiment has the function of emitting light EL1, and includes an electrode 101, an electrode 102, and a unit 103 (see Figure 15B).

[0500] Optical EL1 has a spectrum φ1, which has a maximum peak at a wavelength λ1 nm.

[0501] Electrode 102 has a region that overlaps with electrode 101. Unit 103 has a region sandwiched between electrode 101 and electrode 102, and unit 103 comprises layers 111, 112, and 113.

[0502] Layer 111 comprises a region sandwiched between layers 112 and 113, and layer 111 contains a light-emitting material.

[0503] Layer 112 comprises layer 112A and layer 112B. Layer 112B includes a region sandwiched between layer 112A and layer 111, and layer 112B is in contact with layer 112A.

[0504] Layer 112A has a refractive index of 1.86 for light with a wavelength of 530 nm.

[0505] Layer 112B has a refractive index of 1.67 for light with a wavelength of 530 nm, and a refractive index of 1.67 is smaller than a refractive index of 1.86.

[0506] Furthermore, a refractive index of 1.67 is 0.19 different from a refractive index of 1.86.

[0507] Furthermore, the light-emitting device 2 fabricated in this embodiment has layer 111 with a thickness of 40 nm, and layer 112A has a distance of 40 nm between it and layer 111.

[0508] When the distance d is 40 nm, the thickness t is 40 nm, the wavelength λ is 530 nm, and the refractive index n² is 1.67, the value of (d + t / 2) × n² is 100.2 nm. Also, the value of 0.5 × 0.25 × 530 nm is 66.25 nm, and the value of 1.5 × 0.25 × 530 nm is 198.75 nm. That is, 100.2 nm is in the range of 66.25 nm to 198.75 nm.

[0509] Furthermore, in the light-emitting device 2, layer 112B has a function to suppress the movement of carriers from layer 111 to layer 112A. Specifically, it has a function to suppress the movement of electrons.

[0510] Configuration of Light-Emitting Device 2 Table 3 shows the configuration of the light-emitting device 2. The structural formula of the material used in the light-emitting device described in this embodiment is shown below. Note that Ir(ppy)2(mbfpypy-d3) in the table represents Ir(ppy)2(mbfpypy-d3).

[0511] [Table 3]

[0512] [ka]

[0513] 《Method for fabricating light-emitting device 2》 The light-emitting device 2 described in this embodiment was fabricated using a method comprising the following steps.

[0514] [Step 1] In the first step, electrode 101 was formed. Specifically, it was formed by sputtering using indium tin oxide (ITSO) containing silicon or silicon oxide as the target.

[0515] Electrode 101 contains ITSO and has a thickness of 110 nm and 4 mm 2 It has an area of ​​(2mm x 2mm).

[0516] Next, the substrate on which the electrodes 101 were formed was washed with water, fired at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. -4 The substrate was introduced into a vacuum deposition apparatus where the internal pressure was reduced to approximately Pa, and vacuum firing was performed at 170°C for 30 minutes in the heating chamber within the vacuum deposition apparatus. After that, the substrate was allowed to cool for about 30 minutes.

[0517] [Step 2] In the second step, a layer 104 was formed on the electrode 101. Specifically, the material was co-deposited using a resistance heating method.

[0518] Layer 104 contains N-(1,1'-biphenyl-4-yl)-9,9-dimethyl-N-[4-(9-phenyl-9H-carbazole-3-yl)phenyl]-9H-fluoren-2-amine (abbreviated as PCBBiF) and OCHD-001 in a weight ratio of PCBBiF:OCHD-001 = 1:0.03 and has a thickness of 10 nm.

[0519] [Step 3] In the third step, layer 112A was formed on layer 104. Specifically, material CTM1 was deposited using the resistance heating method.

[0520] Layer 112A contains PCBBiF and has a thickness of 100 nm. Furthermore, PCBBiF has a refractive index of 1.86 for light with a wavelength of 530 nm.

[0521] [Step 4] In the fourth step, layer 112B was formed on layer 112A. Specifically, material CTM2 was deposited using the resistance heating method.

[0522] Layer 112B contains N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-4-yl)-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as mmtBumTPchPAF-04) and has a thickness of 40 nm. Furthermore, mmtBumTPchPAF-04 has a refractive index of 1.67 for light with a wavelength of 530 nm.

[0523] [Step 5] In the fifth step, layer 111 was formed on layer 112B. Specifically, the material was co-deposited using the resistance heating method.

[0524] Layer 111 contains 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), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), and [2-d3-methyl-(2- It contains pyridinyl-κN)benzofl[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: Ir(ppy)2(mbfpypy-d3)) in the ratio BP-Icz(II)Tzn:PCCP:Ir(ppy)2(mbfpypy-d3) = 0.5:0.5:0.10 (by weight) and has a thickness of 40 nm.

[0525] [Step 6] In the sixth step, layer 113A was formed on layer 111. Specifically, the material was deposited using a resistance heating method.

[0526] Layer 113A contains mFBPTzn and has a thickness of 10 nm.

[0527] [Step 7] In the seventh step, layer 113B was formed on layer 113A. Specifically, the material was co-deposited using the resistance heating method.

[0528] Layer 113B contains mPn-mDMePyPTzn and Liq in a ratio of mPn-mDMePyPTzn:Liq = 1:1 (by weight) and has a thickness of 25 nm.

[0529] [Step 8] In the eighth step, layer 105 was formed on layer 113B. Specifically, the material was deposited using the resistance heating method.

[0530] Layer 105 contains Liq and has a thickness of 1 nm.

[0531] [Step 9] In the ninth step, an electrode 102 was formed on layer 105. Specifically, the material was deposited using a resistance heating method.

[0532] Electrode 102 contains Al and has a thickness of 200 nm.

[0533] Operating characteristics of the light-emitting device 2 When power was supplied, the light-emitting device 2 emitted light EL1 (see Figure 15B). The operating characteristics of the light-emitting device 1 were measured (see Figures 22 to 27). The measurements were performed at room temperature.

[0534] Light-emitting device 2 has a brightness of 1000 cd / m². 2 Table 4 shows the main initial characteristics when the light is emitted to a certain degree.

[0535] [Table 4]

[0536] The light-emitting device 2 was found to exhibit excellent characteristics. For example, light-emitting device 2 showed extremely high current efficiency (see Table 2 and Figure 23). Furthermore, light-emitting device 2 showed extremely high external quantum efficiency (see Table 2 and Figure 26). As a result, we were able to provide a novel light-emitting device with superior convenience, usefulness, and reliability.

[0537] <<Synthesis Example 1>> This embodiment describes a method for synthesizing the low refractive index hole transport material described in Embodiment 1.

[0538] First, we will explain the detailed synthesis method of N,N-bis(4-cyclohexylphenyl)-N-(9,9-dimethyl-9H-fluoren-2yl)amine (abbreviated as dchPAF). The structure of dchPAF is shown below.

[0539] [ka]

[0540] <Step 1: Synthesis of N,N-bis(4-cyclohexylphenyl)-N-(9,9-dimethyl-9H-fluoren-2yl)amine (abbreviation: dchPAF)> 10.6 g (51 mmol) of 9,9-dimethyl-9H-fluoren-2-amine, 18.2 g (76 mmol) of 4-cyclohexyl-1-bromobenzene, 21.9 g (228 mmol) of sodium tert-butoxide, and 255 mL of xylene were placed in a three-necked flask. After degassing under reduced pressure, the flask was purged with nitrogen. The mixture was heated and stirred to approximately 50°C. Here, 370 mg (1.0 mmol) of allyl palladium chloride dimer(II) (abbreviated as [(Allyl)PdCl]2) and 1660 mg (4.0 mmol) of di-tert-butyl (1-methyl-2,2-diphenylcyclopropyl)phosphine (abbreviated as cBRIDP®) were added, and the mixture was heated at 120°C for about 5 hours. After that, the temperature of the flask was returned to about 60°C, and about 4 mL of water was added to precipitate the solid. The precipitated solid was filtered off. The filtrate was concentrated, and the resulting solution was purified by silica gel column chromatography. The resulting solution was concentrated to obtain a concentrated toluene solution. This toluene solution was added dropwise to ethanol and reprecipitation occurred. The precipitate was filtered at about 10°C, and the resulting solid was dried under reduced pressure at about 80°C to obtain 10.1 g of the target white solid in a yield of 40%. The synthesis scheme of dchPAF in Step 1 is shown below.

[0541] [ka]

[0542] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 1 above ( 1 The results of the analysis by 1H-NMR are shown below. From this, it was found that dchPAF was successfully synthesized in this synthesis example.

[0543] 1H-NMR.δ(CDCl3):7.60(d,1H,J=7.5Hz),7.53(d,1H,J=8.0Hz),7.37(d,2H,J=7 .5Hz),7.29(td,1H,J=7.5Hz,1.0Hz),7.23(td,1H,J=7.5Hz,1.0Hz),7.19(d,1H ,J=1.5Hz),7.06(m,8H),6.97(dd,1H,J=8.0Hz,1.5Hz),2.41-2.51(brm,2H),1. 79-1.95(m,8H),1.70-1.77(m,2H),1.33-1.45(brm,14H),1.19-1.30(brm,2H).

[0544] Similarly, organic compounds represented by structural formulas (101) to (105) below were synthesized.

[0545] [ka]

[0546] [ka]

[0547] Nuclear magnetic resonance spectroscopy of the above organic compounds ( 1 The results of the analysis (using 1H-NMR) are shown below.

[0548] Structural formula (101) N-(4-cyclohexylphenyl)-N-(3'',5''-diter-butyl-1,1''-biphenyl-4-yl)-N-(9,9-dimethyl-9H-fluoren-2yl)amine (abbreviation: mmtBuBichPAF) 1H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.57(d,1H,J=8.0Hz),7.44-7.49(m,2H) ,7.37-7.42(m,4H),7.31(td,1H,J=7.5Hz,2.0Hz),7.23-7.27(m,2H),7.15-7.19( m,2H),7.08-7.14(m,4H),7.05(dd,1H,J=8.0Hz,2.0Hz),2.43-2.53(brm,1H),1. 81-1.96(m,4H),1.75(d,1H,J=12.5Hz),1.32-1.48(m,28H),1.20-1.31(brm,1H).

[0549] Structural formula (102): N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF) 1 H-NMR (300MHz, CDCl3): δ=7.63(d,J=6.6Hz,1H),7.58(d,J=8.1Hz,1H),7.4 2-7.37(m,4H),7.36-7.09(m,14H),2.55-2.39(m,1H),1.98-1.20(m,51H).

[0550] Structural formula (103) N-[(3,3',5'-t-butyl)-1,1'-biphenyl-5-yl]-N-(4-cyclohexylphenyl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBichPAF) 1H-NMR.δ(CDCl3):7.63(d,1H,J=7.5Hz),7.56(d,1H,J=8.5Hz),7.37-40(m, 2H),7.27-7.32(m,4H),7.22-7.25(m,1H),7.16-7.19(brm,2H),7.08-7.15 (m,4H),7.02-7.06(m,2H),2.43-2.51(brm,1H),1.80-1.93(brm,4H),1.71 -1.77(brm,1H),1.36-1.46(brm,10H),1.33(s,18H),1.22-1.30(brm,10H).

[0551] Structural formula (104) N-(1,1'-biphenyl-2-yl)-N-[(3,3',5'-tri-t-butyl)-1,1'-biphenyl-5-yl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumBioFBi) 1 H-NMR.δ(CDCl3):7.57(d,1H,J=7.5Hz),7.40-7.47(m,2H),7.32-7.39(m,4H),7.27-7.31(m,2H ),7.27-7.24(m,5H),6.94-7.09(m,6H),6.83(brs,2H),1.33(s,18H),1.32(s,6H),1.20(s,9H).

[0552] Structural formula (105) N-(4-tert-butylphenyl)-N-(3,3'',5,5''-tetra-t-butyl-1,1':3',1''-terphenyl-5'-yl)-9,9,-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPtBuPAF) 1 H-NMR.δ(CDCl3):7.64(d,1H,J=7.5Hz),7.59(d,1H,J=8.0Hz),7.38-7.43(m,4H),7.29-7.36(m,8H) ,7.24-7.28(m,3H),7.19(d,2H,J=8.5Hz),7.13(dd,1H,J=1.5Hz,8.0Hz),1.47(s,6H),1.32(s,45H).

[0553] Structural formula (106) N-(1,1'-biphenyl-2-yl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-02) 1 H-NMR.δ(CDCl3):7.56(d,1H,J=7.4Hz),7.50(dd,1H,J=1.7Hz),7.33-7.46(m,11H),7.27-7.29(m,2H),7.22(dd,1H,J=2.3Hz),7 .15(d,1H,J=6.9Hz),6.98-7.07(m,7H),6.93(s,1H),6.84(d,1H,J=6.3Hz),1.38(s,9H),1.37(s,18H),1.31(s,6H),1.20(s,9H).

[0554] Structural formula (107) N-(4-cyclohexylphenyl)-N-(3,3'',5',5''-tetra-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-02) 1 H-NMR.δ(CDCl3):7.62(d,1H,J=7.5Hz),7.56(d,1H,J=8.0Hz),7.50(dd,1H,J=1.7Hz),7.4 6-7.47(m,2H),7.43(dd,1H,J=1.7Hz),7.37-7.39(m,3H),7.29-7.32(m,2H),7.23-7.25(m ,2H),7.20(dd,1H,J=1.7Hz),7.09-7.14(m,5H),7.05(dd,1H,J=2.3Hz),2.46(brm,1H),1. 83-1.88(m,4H),1.73-1.75(brm,1H),1.42(s,6H),1.38(s,9H),1.36(s,18H),1.29(s,9H)

[0555] Structural formula (108) N-(1,1'-biphenyl-2-yl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPoFBi-03) 1 H-NMR.δ(CDCl3):7.55(d,1H,J=7.4Hz),7.50(dd,1H,J=1.7Hz),7.42-7.43(m,3H),7.27-7.39(m,10H),7.18-7.25(m,4H),7.00-7.12 (m,4H),6.97(dd,1H,J=6.3Hz,1.7Hz),6.93(d,1H,J=1.7Hz),6.82(dd,1H,J=7.3Hz,2.3Hz),1.37(s,9H),1.36(s,18H),1.29(s,6H).

[0556] Structural formula (109) N-(4-cyclohexylphenyl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-5-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: mmtBumTPchPAF-03) 1 H-NMR.δ(CDCl3):7.62(d,1H,J=7.5Hz),7.56(d,1H,J=8.6Hz),7.51(dd,1H,J=1.7Hz),7.48(dd,1H,J=1.7Hz),7.46(dd,1H,J=1.7Hz),7.42(dd,1 H,J=1.7Hz),7.37-7.39(m,4H),7.27-7.33(m,2H),7.23-7.25(m,2H),7. 05-7.13(m,7H),2.46(brm,1H),1.83-1.90(m,4H),1.73-1.75(brm,1H), 1.41(s,6H),1.37(s,9H),1.35(s,18H).

[0557] All of the above substances have an ordinary refractive index of 1.50 to 1.75 in the blue light emission region (455 nm to 465 nm), or an ordinary refractive index of 1.45 to 1.70 in 633 nm light, which is commonly used for measuring refractive index.

[0558] ≪Synthesis Example 2≫ This embodiment describes a method for synthesizing the low refractive index hole transport material described in Embodiment 1.

[0559] The synthesis method for N-(4-cyclohexylphenyl)-N-(3'',5',5''-tri-t-butyl-1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine (abbreviated as mmtBumTPchPAF-04) is described below. The structure of mmtBumTPchPAF-04 is shown below.

[0560] [ka]

[0561] <Step 1: Synthesis of 4-bromo-3'',5',5''-tri-tert-butyl-1,1':3',1''-terphenyl> 9.0 g (20.1 mmol) of 2-(3',5,5'-tri-tert-butyl[1,1'-biphenyl]-3-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane, 6.8 g (24.1 mmol) of 1-bromo-4-iodobenzene, 8.3 g (60.3 mmol) of potassium carbonate, 100 mL of toluene, 40 mL of ethanol, and 30 mL of tap water were placed in a three-necked flask. After degassing under reduced pressure, the flask was purged with nitrogen, and 91 mg (0.40 mmol) of palladium acetate and 211 mg (0.80 mmol) of triphenylphosphine were added. This mixture was heated at 80°C for approximately 4 hours. After returning to room temperature, the mixture was separated into an organic layer and an aqueous layer. Magnesium sulfate was added to this solution, and the water was dried and the solution was concentrated. The resulting hexane solution was purified by silica gel column chromatography to obtain 6.0 g of the target white solid in a yield of 62.5%. The synthesis scheme for 4-bromo-3'',5',5''-tri-tert-butyl-1,1':3',1''-terphenyl in Step 1 is shown below.

[0562] [ka]

[0563] <Step 2: Synthesis of mmtBumTPchPAF-04> In a three-necked flask, 3.0 g (6.3 mmol) of 4-bromo-3'', 5',5''-tri-tert-butyl-1,1':3',1''-terphenyl obtained in Step 1, 2.3 g (6.3 mmol) of N-(4-cyclohexylphenyl)-N-(9,9-dimethyl-9H-fluoren-2yl)amine, 1.8 g (18.9 mmol) of sodium tert butoxide, and 32 mL of toluene were placed. After degassing under reduced pressure, the flask was purged with nitrogen, and 72 mg (0.13 mmol) of bis(dibenzylideneacetone)palladium(0) and 76 mg (0.38 mmol) of tri-tert-butylphosphine were added. This mixture was heated at 80°C for approximately 2 hours. After that, the flask temperature was reduced to approximately 60°C, approximately 1 mL of water was added, and the precipitated solid was filtered off and washed with toluene. The filtrate was concentrated, and the resulting toluene solution was purified by silica gel column chromatography. The obtained solution was concentrated to obtain a concentrated toluene solution. Ethanol was added to this toluene solution and concentrated under reduced pressure to obtain an ethanol suspension. The solid precipitated in this ethanol suspension was filtered at approximately 20°C, and the obtained solid was dried under reduced pressure at approximately 80°C to obtain 4.1 g of the target white solid in a yield of 85%. The synthesis scheme of mmtBumTPchPAF-04 in Step 2 is shown below.

[0564] [ka]

[0565] Furthermore, nuclear magnetic resonance spectroscopy of the white solid obtained in step 2 above ( 1 The results of the analysis by 1H-NMR are shown below. From this, it was found that mmtBumTPchPAF-04 was successfully synthesized in this synthesis example.

[0566] 11H-NMR. δ (CDCl3): 7.63 (d, 1H, J = 7.5 Hz), 7.52 - 7.59 (m, 7H), 7.44 - 7.45 (m, 4H), 7.39 (d, 1H, J = 7.4 Hz), 7.31 (dd, 1H, J = 7.4 Hz), 7.19 (d, 2H, J = 6.6 Hz), 7.12 (m, 4H), 7.07 (d, 1H, J = 9.7 Hz), 2.48 (brm, 1H), 1.84 - 1.93 (brm, 4H), 1.74 - 1.76 (brm, 1H), 1.43 (s, 18H), 1.39 (brm, 19H), 1.24 - 1.30 (brm, 1H).

Description of Symbols

[0567] CAP: layer, 101: electrode, 102: electrode, 103: unit, 104: layer, 105: layer, 106: intermediate layer, 106A: layer, 106B: layer, 111: layer, 112: layer, 112A: layer, 112B: layer, 112C: layer, 113: layer, 113A: layer, 113B: layer, 150: light-emitting device, 400: substrate, 401: electrode, 403: EL layer, 404: electrode, 405: sealant, 406: sealant, 407: encapsulation substrate, 412: pad, 420: IC chip, 601: source line drive circuit, 602: pixel section, 603: gate line drive circuit, 604: encapsulation substrate, 605: 607: Space, 608: Wiring, 610: Element substrate, 611: Switching FET, 612: Current control FET, 613: Electrode, 614: Insulator, 616: EL layer, 617: Electrode, 618: Light-emitting device, 623: FET, 700: Light-emitting panel, 951: Substrate, 952: Electrode, 953: Insulating layer, 954: Partition layer, 955: EL layer, 956: Electrode, 1001: Substrate, 1002: Underlying insulating film, 1003: Gate insulating film, 1006: Gate electrode, 1007: Gate electrode, 1008: Gate electrode, 1020: Interlayer insulating film, 1021: Interlayer insulating film, 1022: Electrode, 1024B: Electrode, 1024G: Electrode, 1024R: Electrode, 1024W: Electrode, 1025: Partition, 1028: EL layer, 1029: Electrode, 1031: Encapsulation substrate, 1032: Sealing material, 1033: Substrate, 1034B: Coloring layer, 1034G: Coloring layer, 1034R: Coloring layer, 1035: Black matrix, 1036: Overcoat layer, 1037: Interlayer insulating film, 1040: Pixel section, 1041: Drive circuit section, 1042: Peripheral section, 2001: Housing, 2002: Light source, 2100: Robot, 2101: Illuminance sensor, 2102: Microphone, 2103: Upper part Camera, 2104: Speaker, 2105: Display, 2106: Lower camera, 2107: Obstacle sensor, 2108: Moving mechanism, 2110: Processing unit, 3001: Lighting device, 5000: Enclosure, 5001: Display unit, 5002: Display unit, 5003: Speaker, 5004: LED lamp, 5006: Connection terminal, 5007: Sensor, 5008: Microphone, 5012: Support unit, 5013: Earphone, 5100: Cleaning robot, 5101: Display, 5102: Camera, 5103: Brush, 5104: Operation button, 5120: Dust, 5140: Portable electronic device,5200: Display area, 5201: Display area, 5202: Display area, 5203: Display area, 7101: Enclosure, 7103: Display unit, 7105: Stand, 7107: Display unit, 7109: Operation keys, 7110: Remote control unit, 7201: Main unit, 7202: Enclosure, 7203: Display unit, 7204: Keyboard, 7205: External connection port, 7206: Pointing device, 7210: Display unit, 7401: Enclosure, 7402: Display unit, 7403: Operation buttons, 7404: External connection port, 7405: Speaker, 7406: Microphone, 9310: Portable information terminal, 9311: Function panel, 9313: Hinge, 9315: Enclosure,

Claims

1. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 500 nm and 600 nm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm.

2. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 500 nm and 600 nm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

3. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 500 nm and 600 nm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

4. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 500 nm and 600 nm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of the wavelength λnm is 1.4 or more and 1.75 or less.

5. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a photoluminescent material and a fourth organic compound, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 500 nm and 600 nm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The fourth organic compound is a compound having an anthracene skeleton and a heterocyclic skeleton, or a compound having a π-electron-deficient heteroaromatic ring skeleton, in the light-emitting device.

6. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 600 nm and 700 nm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm.

7. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 600 nm and 700 nm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

8. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 600 nm and 700 nm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

9. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a light-emitting material that emits photoluminescent light, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 600 nm and 700 nm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of the wavelength λnm is 1.4 or more and 1.75 or less.

10. It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer comprises a photoluminescent material and a fourth organic compound, The spectrum of the aforementioned photoluminescent light has a maximum peak at a wavelength λnm, and the wavelength λnm is between 600 nm and 700 nm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The fourth organic compound is a compound having an anthracene skeleton and a heterocyclic skeleton, or a compound having a π-electron-deficient heteroaromatic ring skeleton, in the light-emitting device.

11. A light-emitting device having the function of emitting green light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm.

12. A light-emitting device having the function of emitting green light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

13. A light-emitting device having the function of emitting green light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

14. A light-emitting device having the function of emitting green light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of the wavelength λnm is 1.4 or more and 1.75 or less.

15. A light-emitting device having the function of emitting green light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer in the precedent comprises a luminescent material and a fourth organic compound, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The fourth organic compound is a compound having an anthracene skeleton and a heterocyclic skeleton, or a compound having a π-electron-deficient heteroaromatic ring skeleton, in the light-emitting device.

16. A light-emitting device having the function of emitting red light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm.

17. A light-emitting device having the function of emitting red light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of an aromatic amine skeleton, a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

18. A light-emitting device having the function of emitting red light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer, a fifth layer, and a sixth layer. The fifth layer comprises a region sandwiched between the fourth layer and the sixth layer, The sixth layer comprises a region sandwiched between the fifth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The sixth layer has a third organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The third organic compound is a light-emitting device having at least one of a carbazole skeleton, a thiophene skeleton, and a furan skeleton.

19. A light-emitting device having the function of emitting red light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. A light-emitting device wherein the refractive index of the thin film of the second organic compound for light of the wavelength λnm is 1.4 or more and 1.75 or less.

20. A light-emitting device having the function of emitting red light, It has an anode, a cathode, a first layer, and a second layer. The first layer comprises a region sandwiched between the second layer and the cathode, The second layer comprises a region sandwiched between the anode and the first layer, The first layer in the precedent comprises a luminescent material and a fourth organic compound, The spectrum of the aforementioned light has a maximum peak at wavelength λnm. The aforementioned second layer comprises a fourth layer and a fifth layer, The fifth layer comprises a region sandwiched between the fourth layer and the first layer, The fourth layer has the first organic compound, The fifth layer has a second organic compound, The refractive index of the thin film of the second organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the first organic compound for light of wavelength λnm. The fourth organic compound is a compound having an anthracene skeleton and a heterocyclic skeleton, or a compound having a π-electron-deficient heteroaromatic ring skeleton, in the light-emitting device.

21. In any one of claims 1 to 20, A light-emitting device in which the difference between the refractive index of the thin film of the first organic compound for light of wavelength λnm and the refractive index of the thin film of the second organic compound for light of wavelength λnm is 0.1 or more and 1.0 or less.

22. In any one of claims 1 to 21, It has a third layer, The third layer comprises a region sandwiched between the first layer and the cathode, The third layer has a fifth organic compound, The fifth organic compound is a light-emitting device having at least one diazine ring or triazine ring.

23. In any one of claims 1 to 21, It has a third layer and a seventh layer, The third layer comprises a region sandwiched between the first layer and the seventh layer, The seventh layer comprises a region sandwiched between the third layer and the cathode, The third layer has a fifth organic compound, The seventh layer has the sixth organic compound, A light-emitting device wherein the refractive index of the thin film of the fifth organic compound for light of wavelength λnm is smaller than the refractive index of the thin film of the sixth organic compound for light of wavelength λnm.

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