Light-emitting devices

Abstract

To provide a novel light-emitting device having a microcavity structure, which is capable of improving the light-emitting efficiency more than ever before.SOLUTION: In a light-emitting device having a microcavity structure that emits light in the near-infrared region, one or both of a first electrode (reflective electrode) and a second electrode (semi-transparent semi-reflective electrode) exhibit higher reflectance for light in the near-infrared region (e.g., light of 850 nm) than for light in the visible light region (400 nm or more and less than 750 nm).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] One aspect of the present invention relates to a light-emitting device, a light-emitting apparatus, an electronic device, and a lighting apparatus. However, one aspect of the present invention is not limited thereto. That is, one aspect of the present invention relates to an article, a method, a manufacturing method, or a driving method. Alternatively, one aspect of the present invention relates to a process, a machine, a manufacture, or a composition of matter. [Background technology]

[0002] Light-emitting devices (also called light-emitting elements or organic EL elements), which consist of an EL layer sandwiched between a pair of electrodes, have properties such as being thin and lightweight, having fast response to input signals, and low power consumption, and displays that use these elements are attracting attention as next-generation flat panel displays.

[0003] In a light-emitting device, when a voltage is applied between a pair of electrodes, electrons and holes injected from each electrode recombine in the EL layer, causing the light-emitting substance (organic compound) contained in the EL layer to enter an excited state, and light is emitted when the excited state returns to the ground state. There are two types of excited states: singlet excited state (S * ) and triplet excited states (T * ) and emission from the singlet excited state is called fluorescence, and emission from the triplet excited state is called phosphorescence. The statistical generation ratio of these in a light-emitting device is S * :T * The ratio is thought to be 1:3. The emission spectrum obtained from a luminescent material is specific to that material, and by using different types of organic compounds as luminescent materials, it is possible to obtain light-emitting devices that emit light of a variety of colors.

[0004] Regarding such light-emitting devices, improvements to the device structure and material development have been carried out to improve the device characteristics, but in order to improve the light-emitting efficiency of light-emitting devices, it is important to improve the light extraction efficiency from the light-emitting device. To improve the light extraction efficiency from light-emitting devices, a method has been proposed in which a micro-optical resonator (microcavity) structure that utilizes the optical resonance effect between a pair of electrodes is adopted to increase the light intensity at a specific wavelength (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-182127 Summary of the Invention [Problem to be solved by the invention]

[0006] In light-emitting devices with a microcavity structure, it is preferable to use electrode materials with high reflectivity for the reflective electrode and semi-transparent / semi-reflective electrode. However, when the light emitted from the EL layer between the two electrodes is in the general visible light range (around 400 nm to 750 nm), using these highly reflective materials and increasing the film thickness to further increase reflectivity causes a problem of increased loss due to absorption of part of the light by the semi-transparent / semi-reflective electrode, resulting in reduced luminous efficiency. Therefore, in light-emitting devices that emit light in the general visible light range, efficiency has been improved by making the film thickness of the semi-transparent / semi-reflective electrode thinner.

[0007] Therefore, one aspect of the present invention provides a novel light-emitting device having a microcavity structure, which can improve the luminous efficiency compared to conventional light-emitting devices, and a novel light-emitting device having a microcavity structure, which can improve the reliability of the element.

[0008] Note that the description of these problems does not preclude the existence of other problems. Note that one embodiment of the present invention does not necessarily solve all of these problems. Note that problems other than these will become apparent from the description of the specification, drawings, claims, etc., and it is possible to extract other problems from the description of the specification, drawings, claims, etc. [Means for solving the problem]

[0009] Simulations have revealed that in light-emitting devices having a microcavity structure, when the light emitted from the EL layer is in the near-infrared region (around 750 nm to 1000 nm), and when highly reflective materials such as gold (Au), silver (Ag), or copper (Cu) are used for the electrodes of the light-emitting device, the semi-transmitting / semi-reflective electrode exhibits higher reflectivity for light in the near-infrared region than for light in the visible region within a specific thickness range. In this specification, the reflectivity of the reflective electrode for visible light (light with a wavelength of 400 nm or more but less than 750 nm) or near-infrared light (light with a wavelength of 750 nm or more but less than 1000 nm) is 40% to 100%, preferably 70% to 100%, and the reflectivity of the semi-transmitting / semi-reflective electrode for visible light or near-infrared light is 20% to 80%, preferably 40% to 70%.

[0010] Therefore, in a light-emitting device having a microcavity structure that emits light in the near-infrared region, a light-emitting device with high luminous efficiency can be obtained by using a highly reflective material for the reflective electrode of the light-emitting device, or for both the reflective electrode and the semi-transparent / semi-reflective electrode, and by setting the film thickness of the semi-transparent / semi-reflective electrode to 20 nm or more and 60 nm or less.

[0011] Furthermore, by increasing the thickness of the electrode within the above range compared to conventional methods, it is possible to form an electrode with high reflectivity while suppressing light absorption. Furthermore, by increasing the thickness, it is possible to reduce the resistance of the electrode, thereby obtaining a light-emitting device with high luminous efficiency and reduced driving voltage.

[0012] One embodiment of the present invention is a light-emitting device having an EL layer between a first electrode and a second electrode, the first electrode being a reflective electrode, and the second electrode being a semi-transparent semi-reflective electrode having both the functions of transmitting and reflecting light (particularly light in the near-infrared region (750 nm to 1000 nm)), in which the EL layer emits light in the near-infrared region, and one or both of the first electrode and the second electrode exhibit higher reflectance for light in the near-infrared region (e.g., light with a wavelength of 850 nm) than for light in the visible light region (e.g., light with a wavelength of 500 nm).

[0013] Another embodiment of the present invention is a light-emitting device having an EL layer between a first electrode and a second electrode, the first electrode being a reflective electrode, and the second electrode being a semi-transmissive / semi-reflective electrode having both the function of transmitting and reflecting light (particularly light in the near-infrared region (750 nm to 1000 nm)), in which the EL layer emits light in the near-infrared region, and one or both of the first electrode and the second electrode exhibits higher reflectivity for light in the near-infrared region (e.g., light with a wavelength of 850 nm) than for light in the visible light region (e.g., light with a wavelength of 500 nm), and the second electrode has a thickness of 20 nm to 60 nm, preferably 30 nm to 60 nm, and more preferably 40 nm to 50 nm.

[0014] In each of the above structures, it is preferable that an organic layer be provided in contact with the second electrode, and that the organic layer have a refractive index of 1.7 or more.

[0015] In the above-described configuration, the thickness of the organic layer is set to 80 nm or more and 160 nm or less, and more preferably 80 nm or more and 120 nm or less.

[0016] Another embodiment of the present invention is a light-emitting device including an EL layer between a first electrode and a second electrode, the first electrode being a reflective electrode, and the second electrode being a semi-transparent / semi-reflective electrode. The EL layer contains a light-emitting substance that has an emission peak in the near-infrared region (a wavelength range of 750 nm to 1000 nm), and the EL layer emits light with a longer wavelength than the emission peak of the light-emitting substance.

[0017] In each of the above configurations, the first electrode or the second electrode preferably includes at least one of gold (Au), silver (Ag), and copper (Cu).

[0018] In each of the above structures, the first electrode preferably exhibits a reflectance of 90% or more for light with a wavelength of 850 nm.

[0019] In each of the above configurations, the second electrode preferably exhibits a reflectance of 90% or more for light with a wavelength of 850 nm.

[0020] In each of the above structures, the light-emitting material is preferably a phosphorescent material.

[0021] In each of the above structures, the light-emitting substance is preferably an organometallic complex represented by the general formula (G1).

[0022] [ka]

[0023] In the above general formula (G1), R 1 ~R 11 each independently represents hydrogen or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent alkyl groups having 1 to 6 carbon atoms. 5 ~R 9 At least two of the groups represent an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, n is 2 or 3, and L represents a monoanionic ligand.

[0024] Note that one embodiment of the present invention includes not only a light-emitting device having the above-described light-emitting device, but also electronic devices to which the light-emitting device or light-emitting device is applied (specifically, electronic devices having a light-emitting device or light-emitting device and a connection terminal or an operation key) and lighting devices (specifically, lighting devices having a light-emitting device or light-emitting device and a housing). Therefore, the term "light-emitting device" in this specification refers to an image display device or a light source (including a lighting device). Furthermore, the term "light-emitting device" also includes a module in which a connector, such as an FPC (Flexible Printed Circuit) or a TCP (Tape Carrier Package), is attached to a light-emitting device, a module in which a printed wiring board is provided at the end of a TCP, or a module in which an IC (Integrated Circuit) is directly mounted on a light-emitting device by a COG (Chip On Glass) method. [Effects of the Invention]

[0025] According to one embodiment of the present invention, a novel light-emitting device having a microcavity structure can be provided, which can have improved luminous efficiency compared to conventional light-emitting devices.Furthermore, according to one embodiment of the present invention, a novel light-emitting device having a microcavity structure can be provided, which can have improved reliability.

[0026] Note that the description of these effects does not preclude the existence of other effects. Note that one embodiment of the present invention does not necessarily have all of these effects. Note that effects other than these will become apparent from the description in the specification, drawings, claims, etc., and it is possible to extract other effects from the description in the specification, drawings, claims, etc. [Brief explanation of the drawings]

[0027] [Figure 1] 1A and 1B are diagrams illustrating the structure of a light-emitting device. [Figure 2] FIG. 2 is a diagram illustrating the structure of a light-emitting device. [Figure 3]FIG. 3 is a diagram showing the simulation results of the reflectance of the electrode material. [Figure 4] FIG. 4 shows the results of a simulation of the EL emission spectrum emitted in the front direction. [Figure 5] FIG. 5 is a diagram showing the results of a simulation of the light extraction efficiency of the EL emission spectrum emitted in the front direction. [Figure 6] FIG. 6 is a diagram showing the simulation results of the peak intensity of the EL emission spectrum emitted in the front direction. [Figure 7] 7A and 7B are diagrams illustrating a light emitting device. [Figure 8] 8A, 8B, 8C, 8D, 8E, 8F, and 8G are diagrams illustrating electronic devices. [Figure 9] 9A, 9B, and 9C are diagrams illustrating electronic devices. [Figure 10] 10A and 10B are diagrams illustrating an automobile. [Figure 11] 11A and 11B are diagrams illustrating the lighting device. [Figure 12] FIG. 12 is a diagram illustrating a light-emitting device. [Figure 13] FIG. 13 is a graph showing the current density-radiant emittance characteristics of light-emitting device 1 and light-emitting device 2. As shown in FIG. [Figure 14] FIG. 14 is a graph showing the voltage-current density characteristics of light-emitting device 1 and light-emitting device 2. As shown in FIG. [Figure 15] FIG. 15 is a graph showing the current density-external quantum efficiency characteristics of light-emitting device 1 and light-emitting device 2. As shown in FIG. [Figure 16] FIG. 16 is a graph showing the voltage-radiant emittance characteristics of light-emitting device 1 and light-emitting device 2. As shown in FIG. [Figure 17] FIG. 17 is a diagram showing the spectral radiance of light-emitting device 1 and light-emitting device 2. As shown in FIG. [Figure 18] Figure 18 shows the emission spectrum of the organometallic complex, [Ir(dmdpbq)2(dpm)]. [Figure 19]FIG. 19 is a graph showing the viewing angle dependence of light-emitting device 1 and light-emitting device 2. In FIG. [Figure 20] FIG. 20 shows the reliability test results of the light emitting device 1 and the light emitting device 2. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and various changes in form and details are possible without departing from the spirit and scope of the present invention. Therefore, the present invention should not be interpreted as being limited to the description of the embodiments shown below.

[0029] For ease of understanding, the position, size, range, etc. of each component shown in the drawings may not represent the actual position, size, range, etc. Therefore, the disclosed invention is not necessarily limited to the position, size, range, etc. disclosed in the drawings, etc.

[0030] In addition, in this specification and the like, when describing the configuration of the invention using drawings, the same reference numerals are used in common between different drawings.

[0031] (Embodiment 1) In this embodiment, a light-emitting device according to one embodiment of the present invention will be described with reference to Fig. 1 and Fig. 2. Note that the same reference symbols are used in Fig. 1 and Fig. 2.

[0032] <Light-emitting device structure> 1 shows an example of a light-emitting device having an EL layer including a light-emitting layer between a pair of electrodes. Specifically, the device has a structure in which an EL layer 103 is sandwiched between a first electrode 101 and a second electrode 102. For example, when the first electrode 101 is an anode, the EL layer 103 has a structure in which a hole injection layer 111, a hole transport layer 112, a light-emitting layer 113, an electron transport layer 114, and an electron injection layer 115 are sequentially stacked as functional layers.

[0033] The light-emitting device according to one embodiment of the present invention has a micro-optical resonator (microcavity) structure, in which one of a pair of electrodes is a reflective electrode and the other is a semi-transparent / semi-reflective electrode, thereby repeatedly reflecting light and amplifying light of a wavelength corresponding to the distance between the electrodes (also referred to as the cavity length or optical path length). The cavity length can be changed by adjusting the thickness of the EL layer or the electrode. When adjusting the cavity length using an electrode, a transparent electrode such as ITO can be used. When adjusting the EL layer 103, the optical path length can be controlled by adjusting the thickness of the carrier transport layer or the carrier injection layer.

[0034] The light-emitting device may have either a top-emission structure or a bottom-emission structure. For example, in a light-emitting device having a top-emission structure as shown in FIG. 2, the first electrode 101 has reflectivity, and the second electrode 102 has semi-transmissive and semi-reflective properties, which have both optical transparency and reflectivity. Specifically, the first electrode 101 is a reflective electrode, and the reflectivity of the electrode for visible light or near-infrared light is 40% or more and 100% or less, preferably 70% or more and 100% or less. The second electrode 102 is a semi-transmissive and semi-reflective electrode, and the reflectivity of the electrode for visible light or near-infrared light is 20% or more and 80% or less, preferably 40% or more and 70% or less. Furthermore, these electrodes all have a resistivity of 1×10 -2 Preferably, the resistivity is Ωcm or less. Therefore, by adjusting the optical distance from the interface (reflective region) between the first electrode 101 and the EL layer 103 to the light-emitting layer 113 (light-emitting region) and the optical distance from the interface (reflective region) between the second electrode 102 and the EL layer 103 to the light-emitting layer 113 (light-emitting region), it is possible to increase the intensity of the desired light (wavelength) emitted from the light-emitting layer 113. Note that, in order to more effectively increase the light extraction efficiency, it is preferable that an organic compound layer (organic cap layer 105) having a molecular weight of 300 to 1200 is formed on the surface of the second electrode 102 (semi-transmissive-semi-reflective electrode) opposite to the surface facing the reflective electrode.

[0035] In a light-emitting device, providing an organic capping layer 105 in contact with the second electrode 102 can reduce the refractive index difference at the interface between the second electrode 102 and air, thereby improving light extraction efficiency. The organic capping layer 105 is preferably an organic compound layer with a molecular weight of 300 to 1200. It is also preferably made of a conductive organic material. When the second electrode 102 is a semi-transparent / semi-reflective electrode, a thin film is required to maintain a certain degree of light transparency, which may result in poor conductivity. Therefore, using a conductive material for the organic capping layer 105 can improve light extraction efficiency while ensuring conductivity and improving the yield of light-emitting device fabrication. An organic compound with low absorption in the desired wavelength range can be preferably used for the organic capping layer 105. The organic compound used for the EL layer 103 can also be used for the organic capping layer 105. In this case, the organic capping layer 105 can be deposited in the same deposition apparatus or deposition chamber as the EL layer 103, allowing for convenient deposition.

[0036] The optical distance from the interface (reflective region) between the first electrode 101 and the EL layer 103 to the light-emitting layer 113 (light-emitting region) is expressed as the product of the refractive index and the distance from the interface (reflective region) between the first electrode 101 and the EL layer 103 to the light-emitting layer 113 (light-emitting region). The optical distance from the interface (reflective region) between the second electrode 102 and the EL layer 103 to the light-emitting layer 113 (light-emitting region) is expressed as the product of the refractive index and the distance from the interface (reflective region) between the second electrode 102 and the EL layer 103 to the light-emitting layer 113 (light-emitting region).

[0037] Therefore, for example, when the refractive index of the first electrode (reflective electrode) 101 is smaller than the refractive index of the EL layer 103, the film thickness of the first electrode 101 can be adjusted so that the optical distance between the first electrode 101 and the second electrode 102 is approximately mλ / 2 (m is a natural number, and λ is the wavelength of the desired light), thereby increasing the intensity of the desired light (wavelength) emitted from the light-emitting layer 113. Note that the intensity of the desired light (wavelength) emitted from the light-emitting layer 113 can be increased by adjusting the thickness of one or more of the hole injection layer 111, the hole transport layer 112, the electron transport layer 114, and the electron injection layer 115.

[0038] Alternatively to the configuration shown in FIG. 2, the light emitting device may have a bottom emission structure in which the first electrode 101 is a semi-transmissive and semi-reflective electrode and the second electrode 102 is a reflective electrode.

[0039] <First electrode and second electrode> As described above, the light-emitting device according to one embodiment of the present invention preferably has a structure in which one of the first electrode 101 and the second electrode 102 is a semi-transparent / semi-reflective electrode and the other is a reflective electrode, in order to obtain high light-emitting efficiency.

[0040] As long as the electrodes fulfill their functions, the following materials can be used in combination. For example, metals, alloys, electrically conductive compounds, and mixtures thereof can be used. Specific examples include In-Sn oxide (ITO), In-Si-Sn oxide (ITSO), In-Zn oxide, and In-W-Zn oxide. Other metals that can be used include aluminum (Al), titanium (Ti), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), and neodymium (Nd), as well as alloys containing these metals in combination. Other examples that can be used include elements belonging to Group 1 or 2 of the periodic table (e.g., lithium (Li), cesium (Cs), calcium (Ca), and strontium (Sr)), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing appropriate combinations of these elements, as well as graphene.

[0041] Of the materials listed above, we conducted a simulation to see how the reflectance behaves with respect to the wavelength of light for gold (Au), silver (Ag), copper (Cu), and aluminum (Al), which have high reflectance. The results are shown in Figure 3.

[0042] The results in Figure 3 show that silver (Ag) exhibits high reflectivity with little effect on the reflectivity of light of different wavelengths, but that it exhibits higher reflectivity for light in the near-infrared region (750-1000 nm) above 750 nm than for light in the visible region (400-750 nm) below 750 nm. Gold (Au) and copper (Cu) also exhibit low reflectivity for light in the visible region (400-750 nm) below 750 nm, but high reflectivity for light in the near-infrared region (750-1000 nm) above 750 nm. Aluminum (Al), which is often used as a material for the reflective electrodes of light-emitting devices, exhibits high reflectivity for light in the visible region, but its reflectivity decreases for light with wavelengths above 750 nm, i.e., light in the near-infrared region.

[0043] Therefore, when the wavelength of light emitted from the light-emitting layer 113 of the light-emitting device is long-wavelength light of 750 nm or more, it is preferable to use gold (Au), silver (Ag), or copper (Cu) as the electrode material for the reflective electrode or semi-transparent / semi-reflective electrode. These electrode materials are preferable because they exhibit higher reflectance for light with a wavelength of 850 nm than for light with a wavelength of 500 nm. Furthermore, these electrode materials are preferable because they exhibit a reflectance of 90% or more at a wavelength of 850 nm.

[0044] Here, we used the light-emitting device 0 having the top-emission structure shown in Figure 2 as a model to simulate the change in the EL emission spectrum emitted in the front direction with changes in the film thickness of the second electrode 102, which is a semi-transmissive and semi-reflective electrode. The results are shown in Figure 4. The element structure of the light-emitting device 0 is also shown in Table 1 below. Note that the light-emitting layer 113 of the light-emitting device 0 contains an organometallic complex, [Ir(dmdpbq)2(dpm)], as a light-emitting substance. Therefore, the light obtained from the light-emitting layer 113 originates from the emission of [Ir(dmdpbq)2(dpm)]. However, optical adjustments are required with changes in the film thickness of the second electrode 102. Therefore, the film thicknesses of the hole-injection layer 111, the electron-injection layer 115, and the organic capping layer 105 are appropriately adjusted so that the emission intensity at a wavelength around 800 nm is maximized.

[0045] [Table 1]

[0046] As shown in FIG. 4 , optical adjustment was performed on the light-emitting device 0 according to the thickness of the second electrode 102. When the thickness of the second electrode 102 was 40 nm, the peak intensity of the EL emission spectrum at a wavelength of approximately 800 nm was maximized. Furthermore, when the thickness of the second electrode 102 was 30 nm or more and 60 nm or less, a narrowed EL emission spectrum was obtained. FIG. 5 shows the relationship between the area of ​​the EL emission spectrum in the front direction and the thickness of the second electrode 102 in the wavelength range of the simulation shown in FIG. 4 . The total amount of light emitted from the front direction was maximized when the thickness of the second electrode 102 was 20 nm or more and 40 nm or less. FIG. 6 shows the relationship between the peak intensity of the EL emission spectrum in the front direction and the thickness of the second electrode 102 in the wavelength range of the simulation shown in FIG. 4 . The peak intensity of the EL emission spectrum in the front direction was maximized when the thickness of the second electrode 102 was 20 nm or more and 60 nm or less. Therefore, the film thickness of the second electrode 102 is preferably 20 nm or more and 60 nm or less, more preferably 30 nm or more and 60 nm or less, and even more preferably 30 nm or more and 50 nm or less.

[0047] Furthermore, the simulation results show that when the emitted light has a wavelength of 750 nm or more, the thickness of the organic cap layer 105 is preferably 80 nm or more and 160 nm or less, and more preferably 80 nm or more and 120 nm or less.

[0048] These electrodes can be fabricated by sputtering or vacuum deposition.

[0049] <Hole injection layer> The hole injection layer 111 is a layer that injects holes from the first electrode 101, which is an anode, to the EL layer 103, and is a layer that contains an organic acceptor material or a material with high hole injection properties.

[0050] An organic acceptor material is a material that can generate holes in an organic compound by causing charge separation between the organic acceptor material and another organic compound whose LUMO level and HOMO level are close to each other. Therefore, compounds having electron-withdrawing groups (halogen groups or cyano groups), such as quinodimethane derivatives, chloranil derivatives, and hexaazatriphenylene derivatives, can be used as organic acceptor materials. For example, 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), 3,6-difluoro-2,5,7,7,8,8-hexacyanoquinodimethane, chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), etc. Among organic acceptor materials, HAT-CN is particularly suitable because of its high acceptor properties and stable film quality against heat. In addition, [3] radialene derivatives are preferred because of their extremely high electron-accepting properties. Specifically, α,α',α''-1,2,3-cyclopropanetriylidene tris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidene tris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidene tris[2,3,4,5,6-pentafluorobenzeneacetonitrile], and the like can be used.

[0051] Examples of materials with high hole injection properties include transition metal oxides such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. In addition, phthalocyanine-based compounds such as phthalocyanine (abbreviated as HPc) and copper phthalocyanine (abbreviated as CuPC) can also be used.

[0052] In addition to the above materials, we also developed low molecular weight compounds such as 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: MTDATA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), 4,4'-bis(N-{4-[N'-(3-methylphenyl)-N'-phenylamino]phenyl}-N-phenylamino)biphenyl (abbreviation: DNTPD), and 1,3,5-tris(N-(4-diphenylaminophenyl)-N-phenylamino)biphenyl (abbreviation: DNTPD). Aromatic amine compounds such as [N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), and 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1) can be used.

[0053] In addition, polymeric compounds (oligomers, dendrimers, polymers, etc.) such as poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD) can be used. Alternatively, polymeric compounds containing added acids, such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviation: PEDOT / PSS) and polyaniline / poly(styrenesulfonic acid) (PAni / PSS), can also be used.

[0054] Furthermore, a composite material containing a hole-transporting material and an acceptor material (electron-accepting material) can also be used as a material with high hole-injection properties. In this case, electrons are extracted from the hole-transporting material by the acceptor material, generating holes in the hole-injection layer 111, and the holes are injected into the light-emitting layer 113 via the hole-transporting layer 112. Note that the hole-injection layer 111 may be formed as a single layer made of a composite material containing a hole-transporting material and an acceptor material (electron-accepting material), or may be formed by laminating the hole-transporting material and the acceptor material (electron-accepting material) as separate layers.

[0055] The hole transport material is 1×10 -6 cm 2 A substance having a hole mobility of 1 / Vs or more is preferred. Note that other substances can be used as long as they have a higher hole transporting property than an electron transporting property.

[0056] The hole-transporting material is preferably a material with high hole-transporting properties, such as a π-electron-rich heteroaromatic compound. Examples of the π-electron-rich heteroaromatic compound include aromatic amine compounds (having a triarylamine skeleton), carbazole compounds (having no triarylamine skeleton), thiophene compounds (compounds having a thiophene skeleton), and furan compounds (compounds having a furan skeleton).

[0057] Examples of the aromatic amine compound include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB or α-NPD), N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (abbreviation: TPD), 4,4'-bis[N-(spiro-9,9'-bifluoren-2-yl)-N-phenylamino]biphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl- 3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), N-(9,9-dimethyl-9H-fluoren-2-yl)-N-{9,9-dimethyl-2-[N'-phenyl-N'-(9,9-dimethyl-9H-fluoren-2-yl)amino]-9H-fluoren-7-yl}phenylamine (abbreviation: DFLADFL), N-(9,9-dimethyl-2-diphenylamino-9H-fluoren-7-yl)diphenylamine (abbreviation: DPNF), 2-[N-(4-diphenylaminophenyl)-N-phenylamino] Spiro-9,9'-bifluorene (abbreviation: DPASF), 2,7-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-spiro-9,9'-bifluorene (abbreviation: DPA2SF), 4,4',4''-tris[N-(1-naphthyl)-N-phenylamino]triphenylamine (abbreviation: 1'-TNATA), 4,4',4''-tris(N,N-diphenylamino)triphenylamine (abbreviation: TDATA), 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino]triphenylamine (abbreviation: m-M TDATA), N,N'-di(p-tolyl)-N,N'-diphenyl-p-phenylenediamine (abbreviation: DTDPPA), 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviation: DPAB), N,N'-bis{4-[bis(3-methylphenyl)amino]phenyl}-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine (abbreviation: DNTPD), 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B), etc.

[0058] Furthermore, examples of aromatic amine compounds having a carbazolyl group include 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9-phenyl-9H-carbazol-3-amine (abbreviation: PCBiF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF), 4 ,4'-Diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBANB), 4,4'-Di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBNBB), 4-phenyldiphenyl-(9-phenyl-9H-carbazol-3-yl)amine (abbreviated as PCA1BP), N,N'-Bis(9-phenyl N,N',N''-triphenyl-N,N',N''-tris(9-phenylcarbazol-3-yl)benzene-1,3,5-triamine (abbreviation: PCA3B), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-bis(9,9-dimethyl-9H-fluoren- N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi(9H-fluorene)-2-amine (abbreviation: PCBNBSF), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-N-[4-(1-naphthyl)phenyl]-9H-fluorene-2-amine (abbreviation: PCBNBF), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]spiro-9,9'-Bifluoren-2-amine (abbreviation: PCBASF), 3-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA1), 3,6-bis[N-(9-phenylcarbazol-3-yl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzPCA2), 3-[N-(1-naphthyl)-N-(9-phenylcarbazol-3-yl)amino]-9-phenylcarbazole (abbreviation: PCzPCN1), 3-[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole (abbreviation: PCzDPA1), 3,6-bis[N-(4-diphenylaminophenyl)-N-phenylamino]-9-phenylcarbazole Examples of suitable fluorene compounds include PCzDPA2, 3,6-bis[N-(4-diphenylaminophenyl)-N-(1-naphthyl)amino]-9-phenylcarbazole (PCzTPN2), 2-[N-(9-phenylcarbazol-3-yl)-N-phenylamino]spiro-9,9'-bifluorene (PCASF), N-[4-(9H-carbazol-9-yl)phenyl]-N-(4-phenyl)phenylaniline (YGA1BP), N,N'-bis[4-(carbazol-9-yl)phenyl]-N,N'-diphenyl-9,9-dimethylfluorene-2,7-diamine (YGA2F), and 4,4',4''-tris(carbazol-9-yl)triphenylamine (TCTA).

[0059] Examples of the carbazole compound (not having a triarylamine skeleton) include 3-[4-(9-phenanthryl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPPn), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), and 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA). Further examples include bicarbazole derivatives (for example, 3,3'-bicarbazole derivatives), such as 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-bicarbazole (abbreviation: mBPCCBP), and 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP).

[0060] Examples of the thiophene compound (a compound having a thiophene skeleton) include 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II), 2,8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III), and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV).

[0061] Examples of the furan compounds (compounds having a furan skeleton) include 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II).

[0062] Other polymer compounds that can be used as hole-transporting materials include poly(N-vinylcarbazole) (abbreviation: PVK), poly(4-vinyltriphenylamine) (abbreviation: PVTPA), poly[N-(4-{N'-[4-(4-diphenylamino)phenyl]phenyl-N'-phenylamino}phenyl)methacrylamide] (abbreviation: PTPDMA), and poly[N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl)benzidine] (abbreviation: Poly-TPD).

[0063] However, the hole transporting material is not limited to the above, and one or more of various known materials may be used as the hole transporting material.

[0064] The acceptor material used for the hole-injection layer 111 can be an oxide of a metal belonging to Groups 4 to 8 of the periodic table. Specific examples include molybdenum oxide, vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, tungsten oxide, manganese oxide, and rhenium oxide. Among these, molybdenum oxide is particularly preferable because it is stable in the air, has low hygroscopicity, and is easy to handle. Alternatively, the organic acceptors described above can also be used.

[0065] The hole injection layer 111 can be formed using various known film formation methods, for example, vacuum deposition.

[0066] <Hole transport layer> The hole transport layer 112 is a layer that transports holes injected from the first electrode 101 by the hole injection layer 111 to the light-emitting layer 113. The hole transport layer 112 is a layer that contains a hole transport material. Therefore, the hole transport layer 112 can be made of the same material as can be used for the hole injection layer 111.

[0067] In the light-emitting device of one embodiment of the present invention, the light-emitting layer 113 preferably contains the same organic compound as that used for the hole-transport layer 112. This is because using the same organic compound for the hole-transport layer 112 and the light-emitting layer 113 allows holes to be efficiently transported from the hole-transport layer 112 to the light-emitting layer 113.

[0068] <Light-emitting layer> The light-emitting layer 113 is a layer containing a light-emitting substance (organic compound). The light-emitting substance that can be used for the light-emitting layer 113 is not particularly limited, and a light-emitting substance that converts singlet excitation energy into light in the visible light region (for example, a fluorescent light-emitting substance) or a light-emitting substance that converts triplet excitation energy into light in the visible light region (for example, a phosphorescent light-emitting substance or a TADF material) can be used. However, in the light-emitting device according to one embodiment of the present invention, when the EL layer emits light having an emission peak in the wavelength range of 750 nm to 1000 nm, the light-emitting layer preferably uses an organic compound (such as an organometallic complex) having an emission peak in the wavelength range of 750 nm to 1000 nm. For example, a phthalocyanine compound (central metal: aluminum, zinc, or the like), a naphthalocyanine compound, a diethylene compound (central metal: nickel), a quinone compound, a diimonium compound, an azo compound, or the like can also be used.

[0069] An example of an organometallic complex having an emission peak in the wavelength range of 750 nm or more and 1000 nm or less is an organometallic complex represented by the following general formula:

[0070] [ka]

[0071] In general formula (G1), R 1 ~R 11 each independently represents hydrogen or an alkyl group having 1 to 6 carbon atoms; R 1 ~R 4 At least two of R represent alkyl groups having 1 to 6 carbon atoms. 5 ~R 9At least two of the groups represent an alkyl group having 1 to 6 carbon atoms, X represents a substituted or unsubstituted benzene ring or naphthalene ring, n is 2 or 3, and L represents a monoanionic ligand.

[0072] In general formula (G1), examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, an isobutyl group, a tert-butyl group, a pentyl group, an isopentyl group, a sec-pentyl group, a tert-pentyl group, a neopentyl group, a hexyl group, an isohexyl group, a 3-methylpentyl group, a 2-methylpentyl group, a 2-ethylbutyl group, a 1,2-dimethylbutyl group, and a 2,3-dimethylbutyl group.

[0073] In general formula (G1), when the benzene ring or naphthalene ring has a substituent, the substituent can be an alkyl group having from 1 to 6 carbon atoms. The above description can be applied to the alkyl group having from 1 to 6 carbon atoms.

[0074] Examples of monoanionic ligands include monoanionic bidentate chelate ligands having a β-diketone structure, monoanionic bidentate chelate ligands having a carboxyl group, monoanionic bidentate chelate ligands having a phenolic hydroxyl group, monoanionic bidentate chelate ligands in which both coordinating elements are nitrogen, and bidentate ligands that form a metal-carbon bond with iridium by cyclometallation.

[0075] The monoanionic ligand is preferably any one of the general formulae (L1) to (L8).

[0076] [ka]

[0077] In general formulas (L1) to (L8), R 51 ~R 89each independently represents hydrogen, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a halogeno group, a vinyl group, a substituted or unsubstituted haloalkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, a substituted or unsubstituted alkylthio group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 13 carbon atoms; A 1 ~A 13 are independently sp bonds to nitrogen and hydrogen. 2 Hybridized carbon or substituted sp 2 It represents a hybrid carbon, and the substituent is any of an alkyl group having 1 to 6 carbon atoms, a halogeno group, a haloalkyl group having 1 to 6 carbon atoms, or a phenyl group.

[0078] Specific examples of the organometallic complex represented by the general formula (G1) include organometallic complexes represented by structural formulas (100) to (107), although the present invention is not limited thereto.

[0079] [ka]

[0080] Note that for the light-emitting layer 113, a substance that emits light of a color other than the above, such as blue, purple, blue-purple, green, yellow-green, yellow, orange, or red, can be used as appropriate.

[0081] The light-emitting layer 113 contains a light-emitting substance (guest material) and one or more organic compounds (host materials, etc.). However, it is preferable to use a substance having a larger energy gap than the light-emitting substance (guest material) as the organic compound (host material, etc.) used here. Note that examples of the one or more organic compounds (host materials, etc.) include organic compounds such as the hole-transporting material that can be used in the hole-transporting layer 112 described above and the electron-transporting material that can be used in the electron-transporting layer 114 described later.

[0082] In the case where the light-emitting layer 113 has a structure including a first organic compound, a second organic compound, and a light-emitting substance, an electron-transporting material can be used as the first organic compound, a hole-transporting material can be used as the second organic compound, and a phosphorescent material, a fluorescent material, a TADF material, or the like can be used as the light-emitting substance. In such a structure, a combination in which the first organic compound and the second organic compound form an exciplex is preferable.

[0083] The light-emitting layer 113 may have a structure in which a plurality of light-emitting layers containing different light-emitting substances are provided to emit different light colors (for example, white light obtained by combining light-emitting colors that are complementary to each other). Alternatively, one light-emitting layer may have a plurality of different light-emitting substances.

[0084] Note that examples of light-emitting substances that can be used for the light-emitting layer 113 include the following.

[0085] First, examples of luminescent substances that convert singlet excitation energy into luminescence include fluorescent substances (fluorescent substances).

[0086] Examples of fluorescent emitting substances that convert singlet excitation energy into luminescence include pyrene derivatives, anthracene derivatives, triphenylene derivatives, fluorene derivatives, carbazole derivatives, dibenzothiophene derivatives, dibenzofuran derivatives, dibenzoquinoxaline derivatives, quinoxaline derivatives, pyridine derivatives, pyrimidine derivatives, phenanthrene derivatives, naphthalene derivatives, etc. Pyrene derivatives are particularly preferred because of their high luminescence quantum yield. Specific examples of pyrene derivatives include N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(dibenzofuran-2-yl)-N,N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6FrAPrn), N,N'-bis(dibenzothiophen-2-yl)-N, N'-diphenylpyrene-1,6-diamine (abbreviation: 1,6ThAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-6-amine] (abbreviation: 1,6BnfAPrn), N,N'-(pyrene-1,6-diyl)bis[(N-phenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-02), N,N'-(pyrene-1,6-diyl)bis[(6,N-diphenylbenzo[b]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), and the like.

[0087] Other compounds include 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)phenyl N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), 4-(10-phenyl-9-anthryl)-4' -(9-Phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), 4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 2,5,8,11-tetra(tert-butyl)perylene (abbreviation: TBP), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenyl)-4-[4-(10-phenyl-9-anthryl)phenyl]-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPBA), perylene, 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), and the like can be used.

[0088] The luminescent material (fluorescent material) that converts singlet excitation energy into luminescence and can be used in the light-emitting layer 113 is not limited to the fluorescent material that exhibits an emission color (emission peak) in the visible light region described above, but can also be a fluorescent material that exhibits an emission color (emission peak) in part of the near-infrared light region (for example, a material that emits red light at 800 nm or more and 950 nm or less).

[0089] Next, examples of luminescent materials that convert triplet excitation energy into luminescence include phosphorescent materials and thermally activated delayed fluorescence (TADF) materials that exhibit thermally activated delayed fluorescence.

[0090] First, examples of phosphorescent materials, which are light-emitting materials that convert triplet excitation energy into light, include organometallic complexes, metal complexes (platinum complexes), and rare earth metal complexes. These materials exhibit different emission colors (emission peaks) depending on the material, and are appropriately selected and used as needed. Among phosphorescent materials, materials that exhibit emission colors (emission peaks) in the visible light region include the following materials.

[0091] Examples of phosphorescent materials that exhibit blue or green and have an emission spectrum with a peak wavelength of 450 nm or more and 570 nm or less (for example, in the case of blue, 450 nm or more and 495 nm or less is preferable, and in the case of green, 495 nm or more and 570 nm or less are preferable), include the following materials:

[0092] For example, tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN 2]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: [ organometallic complexes with a 4H-triazole skeleton, such as tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III) (abbreviated as [Ir(iPr5btz)3]), tris[3-(5-biphenyl)-5-isopropyl-4-phenyl-4H-1,2,4-triazolato]iridium(III), and tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]iridium(III). Organometallic complexes with a 1H-triazole skeleton, such as iridium(III) (abbreviation: [Ir(Mptz1-mp)3]) and tris(1-methyl-5-phenyl-3-propyl-1H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Prptz1-Me)3]), organometallic complexes with an imidazole skeleton, such as fac-tris[1-(2,6-diisopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]) and tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), and bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’] Organometallic complexes with a phenylpyridine derivative having an electron-withdrawing group as a ligand, such as iridium(III) acetylacetonate (abbreviation: FIr(acac)), are also included.

[0093] Examples of phosphorescent materials that exhibit green, yellow-green, or yellow and have an emission spectrum with a peak wavelength of 495 nm or more and 590 nm or less include the following substances. (For example, in the case of green, the peak wavelength is preferably 495 nm or more and 570 nm or less, in the case of yellow-green, the peak wavelength is preferably 530 nm or more and 570 nm or less, and in the case of yellow, the peak wavelength is preferably 570 nm or more and 590 nm or less.)

[0094] For example, 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: [I r(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6-(2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)2(acac)]), (acetylacetonato)bis{4,6-dimethyl-2-[6-(2,6-dimethylphenyl)-4-pyrimidinyl-κN 3]phenyl-κC}iridium(III) (abbreviation: [Ir(dmppm-dmp)2(acac)]) and (acetylacetonato)bis(4,6-diphenylpyrimidinato)iridium(III) (abbreviation: [Ir(dppm)2(acac)]). Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(3,5-dimethyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-Me)2(acac)]) and (acetylacetonato)bis(5-isopropyl-3-methyl-2-phenylpyrazinato)iridium(III) (abbreviation: [Ir(mppr-iPr)2(acac)]). 2’ ) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’ Organometallic iridium complexes with a pyridine skeleton, such as iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-phenyl-2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviation: [Ir(ppy)2(4dppy)]), bis[2-(2-pyridinyl-κN)phenyl-κC][2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC], [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium (abbreviation: [Ir(ppy)2(mdppy)]), and bis(2,4-diphenyl-1,3-oxazolato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(dpo)2(acac)]), bis{2-[4'-(perfluorophenyl)phenyl]pyridinato-N,C 2’}Iridium(III) acetylacetonate (abbreviation: [Ir(p-PF-ph)2(acac)]), bis(2-phenylbenzothiazolato-N,C 2’ ) iridium(III) acetylacetonate (abbreviated as [Ir(bt)2(acac)]), as well as rare earth metal complexes such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]).

[0095] Examples of phosphorescent materials that exhibit yellow, orange, or red and have an emission spectrum with a peak wavelength of 570 nm to 750 nm include the following materials: (For example, in the case of yellow, the peak wavelength is preferably 570 nm to 590 nm, in the case of orange, the peak wavelength is preferably 590 nm to 620 nm, and in the case of red, the peak wavelength is preferably 600 nm to 750 nm.)

[0096] For example, pyrimidinato]iridium(III) such as (diisobutyrylmethanato)bis[4,6-bis(3-methylphenyl)pyrimidinato]iridium(III) (abbreviation: [Ir(5mdppm)2(dibm)]), bis[4,6-bis(3-methylphenyl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(5mdppm)2(dpm)]), and (dipivaloylmethanato)bis[4,6-di(naphthalen-1-yl)pyrimidinato]iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]). Organometallic complexes with an imidine skeleton, (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-5-phenyl-2-pyrazinyl-κN]phenyl-κC}(2,6-dimethyl-3,5-heptanedionato-κN). 2O,O')iridium(III) (abbreviation: [Ir(dmdppr-P)2(dibm)]), bis{4,6-dimethyl-2-[5-(4-cyano-2,6-dimethylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κ) 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-dmCP)2(dpm)]), bis{4,6-dimethyl-2-[5-(5-cyano-2-methylphenyl)-3-(3,5-dimethylphenyl)-2-pyrazinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κN) 2 O,O')iridium(III) (abbreviation: [Ir(dmdppr-m5CP)2(dpm)]), (acetylacetonato)bis[2-methyl-3-phenylquinoxalinato-N,C 2’ ]iridium(III) (abbreviation: [Ir(mpq)2(acac)]), (acetylacetonato)bis(2,3-diphenylquinoxalinato-N,C 2’ )iridium(III) (abbreviation: [Ir(dpq)2(acac)]), (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and organometallic complexes with a pyrazine skeleton, such as 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)]), bis[4,6-dimethyl-2-(2-quinolinyl-κN)phenyl-κC](2,4-pentanedionato-κ 2These include organometallic complexes with a pyridine skeleton, such as (O,O')iridium(III) (abbreviation: [Ir(dmpqn)2(acac)]), platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrinplatinum(II) (abbreviation: [PtOEP]), and rare earth metal complexes such as tris(1,3-diphenyl-1,3-propanedionato)(monophenanthroline)europium(III) (abbreviation: [Eu(DBM)3(Phen)]) and tris[1-(2-thenoyl)-3,3,3-trifluoroacetonato](monophenanthroline)europium(III) (abbreviation: [Eu(TTA)3(Phen)]).

[0097] Next, the following materials can be used as TADF materials, which are light-emitting substances that convert triplet excitation energy into light emission. TADF materials are materials that can upconvert (reverse intersystem crossing) a triplet excited state to a singlet excited state with a small amount of thermal energy, and efficiently emit light (fluorescence) from the singlet excited state. Conditions for efficiently obtaining thermally activated delayed fluorescence include an energy difference between the triplet excitation level and the singlet excitation level of 0 eV or more and 0.2 eV or less, preferably 0 eV or more and 0.1 eV or less. Delayed fluorescence in TADF materials refers to light emission that has a spectrum similar to that of normal fluorescence, but has a significantly long lifetime. Its lifetime is 1×10 -6 seconds or more, preferably 1 x 10 -3 More than a second.

[0098] Specific examples of TADF materials include fullerenes and their derivatives, acridine derivatives such as proflavine, eosin, etc. Also included are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of metal-containing porphyrins include protoporphyrin-tin fluoride complex (abbreviation: SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (abbreviation: SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (abbreviation: SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (abbreviation: SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (abbreviation: SnF2(OEP)), etioporphyrin-tin fluoride complex (abbreviation: SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (abbreviation: PtCl2OEP).

[0099] Other examples include 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 2-{4-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: PCCzPTzn), 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ-TRZ), and 3-[4-(5-phenyl-5,10-dihydrophenazine- Heterocyclic compounds having one or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 10-phenyl-10H,10'H-spiro[acridine-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used.

[0100] In addition, a substance in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded is particularly preferable because the donor property of the π-electron-rich heteroaromatic ring and the acceptor property of the π-electron-deficient heteroaromatic ring are both strengthened, and the energy difference between the singlet excited state and the triplet excited state is reduced.

[0101] In the light-emitting layer 113, when the above-described light-emitting substances (light-emitting substances that convert singlet excitation energy into light emission in the visible light region (e.g., fluorescent light-emitting substances) or light-emitting substances that convert triplet excitation energy into light emission in the visible light region (e.g., phosphorescent light-emitting substances, TADF materials, etc.)) are used, in addition to these light-emitting substances (organic compounds), it is preferable to use the organic compounds shown below (some overlap with the above) from the viewpoint that combinations with are preferable.

[0102] First, when a fluorescent substance is used as the luminescent substance, it is preferable to use a combination of an organic compound such as a condensed polycyclic aromatic compound, such as an anthracene derivative, a tetracene derivative, a phenanthrene derivative, a pyrene derivative, a chrysene derivative, or a dibenzo[g,p]chrysene derivative.

[0103] Specific examples include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3,6-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: DPCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9,10-diphenylanthracene (abbreviation: DPAnth), N,N-diphenyl-9-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole-3-amine (abbreviation: DPAnth), Abbreviation: CzA1PA), 4-(10-phenyl-9-anthryl)triphenylamine (Abbreviation: DPhPA), YGAPA, PCAPA, N,9-diphenyl-N-{4-[4-(10-phenyl-9-anthryl)phenyl]phenyl}-9H-carbazol-3-amine (Abbreviation: PCAPBA), N-(9,10-diphenyl-2-anthryl)-N,9-diphenyl-9H-carbazol-3-amine (Abbreviation: 2PCAPA), 6,12-dimethoxy-5,11-diphenylchrysene, N,N,N',N',N'',N'',N''',N'''-o 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2-anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluorene-9 -yl)-biphenyl-4'-yl}-anthracene (abbreviation: FLPPA), 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 9,9'-bianthryl (abbreviation: BANT), 9,9'-(stilbene-3,3'-diyl)diphenanthrene (abbreviation: DPNS), 9,9'-(stilbene-4,4'-diyl)diphenanthrene (abbreviation: DPNS2), 1,3,Examples include 5-tri(1-pyrenyl)benzene (abbreviation: TPB3), 5,12-diphenyltetracene, and 5,12-bis(biphenyl-2-yl)tetracene.

[0104] When a phosphorescent substance is used as the light-emitting substance, it is preferable to combine it with an organic compound having a triplet excitation energy greater than the triplet excitation energy (energy difference between the ground state and the triplet excited state) of the light-emitting substance. In addition to such organic compounds, the above-mentioned organic compound (second organic compound) having a high hole-transporting property and an organic compound (first organic compound) having a high electron-transporting property may be used in combination.

[0105] In addition to these organic compounds, multiple organic compounds capable of forming an exciplex (e.g., a first organic compound and a second organic compound, a first host material and a second host material, or a host material and an assist material) may be used. When multiple organic compounds are used to form an exciplex, it is preferable to combine a compound that readily accepts holes (a hole-transporting material) with a compound that readily accepts electrons (an electron-transporting material), since this allows for efficient formation of the exciplex. Furthermore, by incorporating a phosphorescent material and an exciplex in the light-emitting layer, ExTET (Exciplex-Triplet Energy Transfer), which is the energy transfer from the exciplex to the light-emitting material, can be efficiently performed, thereby improving the luminous efficiency. Alternatively, a fluorescent material and an exciplex may be incorporated in the light-emitting layer.

[0106] The above materials may be used in combination with low-molecular-weight materials or polymeric materials. Specific examples of polymeric materials include poly(2,5-pyridinediyl) (abbreviated as PPy), poly[(9,9-dihexylfluorene-2,7-diyl)-co-(pyridine-3,5-diyl)] (abbreviated as PF-Py), and poly[(9,9-dioctylfluorene-2,7-diyl)-co-(2,2'-bipyridine-6,6'-diyl)] (abbreviated as PF-BPy). For film formation, known methods (such as vacuum deposition, coating, and printing) can be used as appropriate.

[0107] <Electron transport layer> The electron transport layer 114 is a layer that transports electrons injected from the second electrode 102 by the electron injection layer 115 described later to the light-emitting layer 113. The electron transport layer 114 is a layer that contains an electron transporting material. The electron transporting material used in the electron transport layer 114 has a concentration of 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or higher is preferred. Note that other substances can be used as long as they have a higher electron transporting property than hole transporting property. The electron transport layers (114, 114a, 114b) function as single layers, but can also have a stacked structure of two or more layers as needed to improve device characteristics.

[0108] As an organic compound that can be used for the electron transport layer 114, a material with high electron transport properties, such as a π-electron-deficient heteroaromatic compound, is preferable. Examples of the π-electron-deficient heteroaromatic compound include a compound having a benzofurodiazine skeleton in which a benzene ring is fused as an aromatic ring to a furan ring of the furodiazine skeleton, a compound having a naphthofurodiazine skeleton in which a naphthyl ring is fused as an aromatic ring to a furan ring of the furodiazine skeleton, a compound having a phenanthrofurodiazine skeleton in which a phenanthro ring is fused as an aromatic ring to a furan ring of the furodiazine skeleton, a compound having a benzothienodiazine skeleton in which a benzene ring is fused as an aromatic ring to a thieno ring of the thienodiazine skeleton, a compound having a naphthothienodiazine skeleton in which a naphthyl ring is fused as an aromatic ring to a thieno ring of the thienodiazine skeleton, and a compound having a phenanthrothienodiazine skeleton in which a phenanthro ring is fused as an aromatic ring to a thieno ring of the thienodiazine skeleton. Other examples include metal complexes having a quinoline skeleton, metal complexes having a benzoquinoline skeleton, metal complexes having an oxazole skeleton, metal complexes having a thiazole skeleton, as well as oxadiazole derivatives, triazole derivatives, imidazole derivatives, oxazole derivatives, thiazole derivatives, phenanthroline derivatives, quinoline derivatives having a quinoline ligand, benzoquinoline derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, pyridine derivatives, bipyridine derivatives, pyrimidine derivatives, and other nitrogen-containing heteroaromatic compounds.

[0109] Examples of electron transporting materials include 9-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr), 9-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9PCCzNfpr), and 9-[3-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mPCCzPNfp r), 9-[3-(9'-phenyl-2,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9mPCCzPNfpr-02), 10-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 10mDBtBPNfpr), 10-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 10PCCzNfpr), 12- [(3'-dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 12mDBtBPPnfpr), 9-[4-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pPCCzPNfpr), 9-[4-(9'-phenyl-2,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pPCCzPNfpr- 02), 9-[3'-(6-phenylbenzo[b]naphtho[1,2-d]furan-8-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9mBnfBPNfpr), 9-[3'-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9mDBtBPNfpr-02), 9-{3-[6-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), 11-(3-naphtho[1',2':4,5]furo[2,3-b]pyrazin-9-yl-phenyl)-12-phenylindolo[2,3-a]carbazole (abbreviation: 9mIcz(II)PNfpr), 3-naphtho[1',2':4,5]furo[2,3-b]pyrazin-9-yl-N,N-diphenylbenzenamine (abbreviation: 9mTPANfpr), 10-[4-(9'-phenyl-3,3'-biphenyl)- -9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 10mPCCzPNfpr), 11-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 10-[3-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2': 4,5]furo[2,3-b]pyrazine (abbreviation: 10pPCCzPNfpr), 9-[3-(7H-dibenzo[c,g]carbazol-7-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mcgDBCzPNfpr), 9-{3'-[6-(biphenyl-3-yl)dibenzothiophen-4-yl]biphenyl-3-yl}naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPN fpr-03), 9-{3'-[6-(biphenyl-4-yl)dibenzothiophen-4-yl]biphenyl-3-yl}naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9mDBtBPNfpr-04), 11-[3'-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviated as 11mDBtBPPnfpr-02), etc.

[0110] In addition, 4-[3-(dibenzothiophen-4-yl)phenyl]-8-(naphthalen-2-yl)-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8βN-4mDBtPBfpm), 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[(2 ,2'-binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), and the like can also be used.

[0111] Also, tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), bis(2-methyl-8-quinolinolato)(4-phenylphenolato)aluminum(III) (abbreviation: BAlq), bis(8-quinolinolato)zinc(II) (abbreviation: Zn Metal complexes having a quinoline skeleton or a benzoquinoline skeleton, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and bis[2-(2-hydroxyphenyl)benzothiazolato]zinc(II) (abbreviation: Zn(BTZ)2), can also be used.

[0112] In addition, oxadiazole derivatives such as 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), and 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), and 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ) triazole derivatives such as 3-(4-tert-butylphenyl)-4-(4-ethylphenyl)-5-(4-biphenylyl)-1,2,4-triazole (abbreviated as p-EtTAZ), imidazole derivatives (including benzimidazole derivatives) such as 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviated as TPBI) and 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviated as mDBTBIm-II), and 4,4'-bis(5-methylbenzene)- oxazole derivatives such as (2-oxazol-2-yl)stilbene (abbreviation: BzOs), phenanthroline derivatives such as bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), and 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 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: 2mDBTPDBq-II), and 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II). quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II), and 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 7mDBTPDBq-II).h]quinoxaline derivatives such as quinoxaline (abbreviation: 6mDBTPDBq-II) or dibenzoquinoxaline derivatives, pyridine derivatives such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 4,6-bis[3-(phenanthrene pyrimidine derivatives such as 2-{4-[3-(N-phenyl-9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), and 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm); PCCzPTzn-02, 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), Triazine derivatives such as [phenyl-1,3,5-triazin-2-yl]phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), etc. can be used.

[0113] Furthermore, polymer compounds such as PPy, PF-Py, and PF-BPy can also be used.

[0114] <Electron injection layer> The electron injection layer 115 is a layer for increasing the efficiency of electron injection from the cathode 102, and it is preferable to use a material for which the difference between the work function value of the material of the cathode 102 and the LUMO level value of the material used for the electron injection layer 115 is small (0.5 eV or less). Therefore, the electron injection layer 115 may be made of lithium, cesium, lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF2), 8-(quinolinolato)lithium (abbreviated as Liq), 2-(2-pyridyl)phenolatolithium (abbreviated as LiPP), 2-(2-pyridyl)-3-pyridinolatolithium (abbreviated as LiPPy), 4-phenyl-2-(2-pyridyl)phenolatolithium (abbreviated as LiPPP), lithium oxide (LiO x Alkali metals, alkaline earth metals, such as cesium carbonate, or compounds thereof can be used. Rare earth metal compounds, such as erbium fluoride (ErF3), can also be used.

[0115] 1B, a structure in which a plurality of EL layers are stacked between a pair of electrodes (also referred to as a tandem structure) can be formed by providing a charge generation layer 104 between two EL layers (103a, 103b). Note that in this embodiment, the hole injection layer (111), the hole transport layer (112), the light-emitting layer (113), the electron transport layer (114), and the electron injection layer (115) described in FIG. 8A have the same functions and materials as the hole injection layers (111a, 111b), the hole transport layers (112a, 112b), the light-emitting layers (113a, 113b), the electron transport layers (114a, 114b), and the electron injection layers (115a, 115b) described in FIG. 8B.

[0116] <Charge generation layer> The charge generation layer 104 in the light-emitting device of FIG. 1B has the function of injecting electrons into the EL layer 103a and injecting holes into the EL layer 103b when a voltage is applied between the first electrode (anode) 101 and the second electrode (cathode) 102. The charge generation layer 104 may be configured by adding an electron acceptor to a hole transporting material, or by adding an electron donor to an electron transporting material. Alternatively, both of these configurations may be stacked. By forming the charge generation layer 104 using the above-mentioned materials, it is possible to suppress an increase in driving voltage when EL layers are stacked.

[0117] When an electron acceptor is added to the hole-transporting material in the charge-generation layer 104, the material described in this embodiment can be used as the hole-transporting material. Examples of the electron acceptor include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ) and chloranil. Examples of the electron acceptor include oxides of metals belonging to Groups 4 to 8 of the periodic table. Specific examples include vanadium oxide, niobium oxide, tantalum oxide, chromium oxide, molybdenum oxide, tungsten oxide, manganese oxide, and rhenium oxide.

[0118] When the charge generation layer 104 has a structure in which an electron donor is added to an electron transporting material, the materials described in this embodiment can be used as the electron transporting material. As the electron donor, an alkali metal, an alkaline earth metal, a rare earth metal, or a metal belonging to Groups 2 and 13 of the periodic table, or an oxide or carbonate thereof can be used. Specifically, lithium (Li), cesium (Cs), magnesium (Mg), calcium (Ca), ytterbium (Yb), indium (In), lithium oxide, cesium carbonate, or the like can be preferably used. Alternatively, an organic compound such as tetrathianaphthacene can be used as the electron donor.

[0119] Although FIG. 1B shows a structure in which two EL layers 103 are stacked, a stack structure of three or more EL layers may be formed by providing a charge generation layer between different EL layers. Furthermore, the light-emitting layers 113 (113a, 113b) included in the EL layers (103, 103a, 103b) each contain a light-emitting substance or a combination of multiple substances, and can be configured to emit fluorescent or phosphorescent light of a desired emission color. When multiple light-emitting layers 113 (113a, 113b) are included, the light-emitting layers may emit different colors. In this case, different light-emitting substances and other substances may be used for the stacked light-emitting layers. For example, the light-emitting layer 113a can be blue, and the light-emitting layer 113b can be red, green, or yellow. Alternatively, the light-emitting layer 113a can be red, and the light-emitting layer 113b can be blue, green, or yellow. Furthermore, in the case of a structure in which three or more EL layers are stacked, the light-emitting layer (113a) of the first EL layer can be blue, the light-emitting layer (113b) of the second EL layer can be red, green, or yellow, and the light-emitting layer of the third EL layer can be blue. Alternatively, the light-emitting layer (113a) of the first EL layer can be red, the light-emitting layer (113b) of the second EL layer can be blue, green, or yellow, and the light-emitting layer of the third EL layer can be red. Note that other combinations of light-emitting colors can be used as appropriate, taking into consideration the brightness and characteristics of the multiple light-emitting colors.

[0120] <Substrate> The light-emitting device described in this embodiment mode can be formed on various substrates. Note that the type of substrate is not limited to a specific one. Examples of the substrate include a semiconductor substrate (for example, a single crystal substrate or a silicon substrate), an SOI substrate, a glass substrate, a quartz substrate, a plastic substrate, a metal substrate, a stainless steel substrate, a substrate having stainless steel foil, a tungsten substrate, a substrate having tungsten foil, a flexible substrate, a laminated film, paper containing a fibrous material, or a base film.

[0121] Examples of glass substrates include barium borosilicate glass, aluminoborosilicate glass, soda lime glass, etc. Examples of flexible substrates, laminated films, base films, etc. include plastics such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), synthetic resins such as acrylic resins, polypropylene, polyester, polyvinyl fluoride, polyvinyl chloride, polyamide, polyimide, aramid resin, epoxy resin, inorganic vapor deposition films, and papers.

[0122] The light-emitting device described in this embodiment can be manufactured by a vacuum process such as vapor deposition, or a solution process such as spin coating or ink-jet printing. When a vapor deposition method is used, a physical vapor deposition method (PVD method) such as sputtering, ion plating, ion beam deposition, molecular beam deposition, or vacuum deposition, or a chemical vapor deposition method (CVD method) can be used. In particular, the functional layers included in the EL layer of the light-emitting device (hole injection layers (111, 111a, 111b), hole transport layers (112, 112a, 112b), light-emitting layers (113, 113a, 113b), electron transport layers (114, 114a, 114b), electron injection layers (115, 115a, 115b), and charge generation layers (104, 104a, 104b)) can be formed by a deposition method (vacuum deposition method, etc.), a coating method (dip coating method, die coating method, bar coating method, spin coating method, spray coating method, etc.), a printing method (inkjet method, screen (stencil printing) method, offset (lithographic printing) method, flexography (relief printing) method, gravure method, microcontact method, nanoimprint method, etc.), or the like.

[0123] Note that when a functional layer included in the EL layer of the light-emitting device described above is formed using a composition for a light-emitting device according to one embodiment of the present invention, it is particularly preferable to use a vapor deposition method. For example, when three types of materials (a light-emitting substance, a first organic compound, and a second organic compound) are used to form the light-emitting layers (113, 113a, 113b), the same number of evaporation sources as the materials to be evaporated (three in this case) are used, and co-evaporation is performed by providing a first organic compound 401, a second organic compound 402, and a light-emitting substance 403 in each evaporation source, thereby forming the light-emitting layers (113, 113a, 113b) which are a mixed film of the three evaporation materials on the surface of the substrate 400. However, when a light-emitting device composition obtained by mixing the first organic compound and the second organic compound out of the three materials is used, even if three types of materials are used to form the light-emitting layers (113, 113a, 113b), it is possible to form the light-emitting layers (113, 113a, 113b) which are the same mixed film as the mixed film formed using three evaporation sources by using two evaporation sources and providing a light-emitting device composition 404 and a light-emitting substance 405 in each evaporation source, respectively.

[0124] However, because the composition for a light-emitting device is obtained by mixing compounds having specific molecular structures as described in the first embodiment, even if a plurality of unspecified compounds are mixed and deposited in a single deposition source, it is difficult to obtain film quality comparable to that obtained by co-deposition using different deposition sources for each compound. For example, problems may arise, such as changes in composition due to the fact that some of the mixed materials are deposited first, or the film quality (composition, film thickness, etc.) of the formed film may not be as desired. Furthermore, in mass production processes, problems such as complex equipment specifications and increased maintenance work may arise.

[0125] In this manner, it is preferable to use the composition for a light-emitting device according to one embodiment of the present invention as part of an EL layer or as the light-emitting layer, because this enables the manufacture of a light-emitting device with high productivity while maintaining the device characteristics and reliability of the light-emitting device.

[0126] The functional layers constituting the EL layers (103, 103a, 103b) of the light-emitting device shown in this embodiment (hole injection layers (111, 111a, 111b), hole transport layers (112, 112a, 112b), light-emitting layers (113, 113a, 113b, 113c), electron transport layers (114, 114a, 114b), electron injection layers (115, 115a, 115b), and charge generation layers (104, 104a, 104b)) are not limited to the materials described above, and other materials may be used in combination as long as they fulfill the functions of each layer. Examples of usable materials include high molecular weight compounds (oligomers, dendrimers, polymers, etc.), medium molecular weight compounds (compounds between low molecular weight and high molecular weight: molecular weight 400 to 4000), and inorganic compounds (quantum dot materials, etc.). As the quantum dot material, colloidal quantum dot materials, alloy type quantum dot materials, core-shell type quantum dot materials, core type quantum dot materials, etc. can be used.

[0127] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments.

[0128] (Embodiment 2) In this embodiment, a light-emitting device which is one embodiment of the present invention will be described.

[0129] By applying the element configuration of the light-emitting device according to one embodiment of the present invention, an active matrix light-emitting device or a passive matrix light-emitting device can be manufactured. Note that an active matrix light-emitting device has a configuration in which a light-emitting device and a transistor (FET) are combined. Therefore, both a passive matrix light-emitting device and an active matrix light-emitting device are included in one embodiment of the present invention. Note that the light-emitting device described in the other embodiments can be applied to the light-emitting device described in this embodiment.

[0130] In this embodiment mode, an active matrix light-emitting device will be described with reference to FIG.

[0131] 7A is a top view showing the light-emitting device, and FIG. 7B is a cross-sectional view taken along the chain line A-A' in FIG. 7A. The active matrix light-emitting device has a pixel portion 302, a driver circuit portion (source line driver circuit) 303, and driver circuit portions (gate line driver circuits) (304a, 304b) provided on a first substrate 301. The pixel portion 302 and the driver circuit portion (303, 304a, 304b) are sealed between the first substrate 301 and a second substrate 306 by a sealant 305.

[0132] Furthermore, routing wiring 307 is provided on the first substrate 301. The routing wiring 307 is electrically connected to an FPC 308, which is an external input terminal. The FPC 308 transmits external signals (e.g., video signals, clock signals, start signals, reset signals, etc.) and potentials to the drive circuit units (303, 304a, 304b). A printed wiring board (PWB) may be attached to the FPC 308. The state in which the FPC or PWB is attached is included in the light-emitting device.

[0133] Next, a cross-sectional structure is shown in FIG. 7B.

[0134] The pixel section 302 is formed by a plurality of pixels each having a FET (switching FET) 311, a FET (current control FET) 312, and a first electrode 313 electrically connected to the FET 312. The number of FETs each pixel has is not particularly limited, and can be appropriately provided as needed.

[0135] The FETs 309, 310, 311, and 312 are not particularly limited, and may be, for example, staggered or inverted staggered transistors, or may have a top-gate or bottom-gate transistor structure.

[0136] Note that the crystallinity of the semiconductor that can be used for these FETs 309, 310, 311, and 312 is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. Note that using a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0137] Examples of the semiconductors that can be used include Group 14 elements, compound semiconductors, oxide semiconductors, and organic semiconductors. Typically, semiconductors containing silicon, semiconductors containing gallium arsenide, and oxide semiconductors containing indium can be used.

[0138] The driver circuit unit 303 has an FET 309 and an FET 310. The FET 309 and the FET 310 may be formed of a circuit including transistors of the same polarity (either N-type or P-type), or may be formed of a CMOS circuit including N-type transistors and P-type transistors. Also, a configuration having an external driver circuit may be used.

[0139] The end of the first electrode 313 is covered with an insulator 314. The insulator 314 can be made of an organic compound such as a negative photosensitive resin or a positive photosensitive resin (acrylic resin), or an inorganic compound such as silicon oxide, silicon oxynitride, or silicon nitride. The upper or lower end of the insulator 314 preferably has a curved surface. This can improve the coverage of a film formed on the insulator 314.

[0140] An EL layer 315 and a second electrode 316 are stacked over the first electrode 313. The EL layer 315 has a light-emitting layer, a hole injection layer, a hole transport layer, an electron transport layer, an electron injection layer, a charge generation layer, and the like.

[0141] Note that the structures and materials described in other embodiments can be applied to the structure of the light-emitting device 317 shown in this embodiment. Although not shown here, the second electrode 316 is electrically connected to an FPC 308 that is an external input terminal.

[0142] Although only one light-emitting device 317 is shown in the cross-sectional view of FIG. 7B, multiple light-emitting devices are arranged in a matrix in the pixel region 302. Light-emitting devices capable of emitting three types of light (R, G, B) can be selectively formed in the pixel region 302 to form a light-emitting device capable of full-color display. In addition to the light-emitting devices capable of emitting three types of light (R, G, B), light-emitting devices capable of emitting, for example, white (W), yellow (Y), magenta (M), cyan (C), etc., may be formed. For example, by adding the light-emitting devices capable of emitting several of the above types of light to the light-emitting device capable of emitting three types of light (R, G, B), it is possible to obtain effects such as improved color purity and reduced power consumption. Furthermore, a light-emitting device capable of full-color display may be formed by combining the light-emitting devices with color filters. Color filters of red (R), green (G), blue (B), cyan (C), magenta (M), yellow (Y), etc. may be used.

[0143] The FETs (309, 310, 311, 312) and light-emitting device 317 on the first substrate 301 are provided in a space 318 surrounded by the first substrate 301, the second substrate 306, and the sealant 305, by bonding the second substrate 306 and the first substrate 301 together with the sealant 305. The space 318 may be filled with an inert gas (nitrogen, argon, etc.) or an organic substance (including the sealant 305).

[0144] The sealing material 305 can be made of epoxy resin or glass frit. It is preferable to use a material that is as moisture- and oxygen-impermeable as possible for the sealing material 305. The second substrate 306 can be made of the same material as the first substrate 301. Therefore, various substrates described in other embodiments can be used as appropriate. In addition to glass substrates and quartz substrates, plastic substrates made of FRP (Fiber-Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like can be used as the substrate. When glass frit is used as the sealing material, it is preferable that the first substrate 301 and the second substrate 306 are glass substrates from the viewpoint of adhesiveness.

[0145] In this manner, an active matrix light emitting device can be obtained.

[0146] When forming an active matrix light-emitting device on a flexible substrate, the FET and the light-emitting device may be formed directly on the flexible substrate. Alternatively, the FET and the light-emitting device may be formed on a separate substrate with a release layer, and then the FET and the light-emitting device may be peeled off at the release layer by applying heat, force, laser irradiation, or the like, and then transferred to the flexible substrate. The release layer may be, for example, a laminate of an inorganic film such as a tungsten film and a silicon oxide film, or an organic resin film such as polyimide. Flexible substrates include substrates on which transistors can be formed, as well as paper substrates, cellophane substrates, aramid film substrates, polyimide film substrates, cloth substrates (including natural fibers (silk, cotton, hemp), synthetic fibers (nylon, polyurethane, polyester), or recycled fibers (acetate, cupra, rayon, recycled polyester), etc.), leather substrates, and rubber substrates. Using these substrates can achieve excellent durability and heat resistance, as well as lightweight and thin designs.

[0147] Furthermore, the light-emitting device of an active matrix light-emitting device may be driven to emit light in a pulsed manner (for example, using a frequency of kHz or MHz) for display. Light-emitting devices formed using the above organic compounds have excellent frequency characteristics, which can shorten the driving time of the light-emitting device and reduce power consumption. Furthermore, heat generation is suppressed as the driving time is shortened, which can also reduce deterioration of the light-emitting device.

[0148] Note that the structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiment modes.

[0149] (Embodiment 3) In this embodiment, examples of various electronic devices and automobiles completed by applying a light-emitting device according to one embodiment of the present invention and a light-emitting device including the light-emitting device according to one embodiment of the present invention will be described. Note that the light-emitting device can be applied mainly to a display portion in the electronic devices described in this embodiment.

[0150] The electronic device shown in Figures 8A to 8E may have a housing 7000, a display unit 7001, a speaker 7003, an LED lamp 7004, operation keys 7005 (including a power switch or an operation switch), a connection terminal 7006, a sensor 7007 (including a function to measure force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substance, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared light), a microphone 7008, etc.

[0151] FIG. 8A shows a mobile computer, which may have a switch 7009, an infrared port 7010, etc. in addition to those described above.

[0152] FIG. 8B shows a portable image reproducing device (for example, a DVD reproducing device) equipped with a recording medium, which may have a second display unit 7002, a recording medium reading unit 7011, and the like in addition to the components described above.

[0153] FIG. 8C shows a digital camera with a television receiving function, which may have an antenna 7014, a shutter button 7015, an image receiving unit 7016, and the like in addition to the components described above.

[0154] FIG. 8D shows a mobile information terminal. The mobile information terminal has a function of displaying information on three or more sides of a display unit 7001. Here, an example is shown in which information 7052, information 7053, and information 7054 are displayed on different sides. For example, a user can check information 7053 displayed in a position that can be observed from above the mobile information terminal while the mobile information terminal is stored in a breast pocket of clothes. The user can check the display without taking the mobile information terminal out of the pocket and decide, for example, whether to answer a call.

[0155] FIG. 8E shows a portable information terminal (including a smartphone), which may have a display unit 7001, operation keys 7005, and the like in a housing 7000. The portable information terminal may also have a speaker 9003, a connection terminal 7006, a sensor 9007, and the like. The portable information terminal may also display text and image information on multiple surfaces. Here, an example is shown in which three icons 7050 are displayed. Information 7051, indicated by a dashed rectangle, may also be displayed on another surface of the display unit 7001. Examples of the information 7051 include notifications of incoming emails, SNS messages, phone calls, etc., the title of the email or SNS message, the sender's name, the date and time, the remaining battery level, and the strength of antenna reception. Alternatively, the icon 7050 may be displayed in the position where the information 7051 is displayed.

[0156] FIG. 8F shows a large television device (also referred to as a television or a television receiver), which may include a housing 7000, a display unit 7001, and the like. Here, the configuration is shown in which the housing 7000 is supported by a stand 7018. The television device can be operated using a separate remote control 7111 or the like. The display unit 7001 may be provided with a touch sensor, and operation may be performed by touching the display unit 7001 with a finger or the like. The remote control 7111 may have a display unit that displays information output from the remote control 7111. The channel and volume can be controlled using the operation keys or touch panel of the remote control 7111, and the image displayed on the display unit 7001 can be controlled.

[0157] The electronic devices shown in FIGS. 8A to 8F can have various functions. For example, they can have a function to display various information (still images, videos, text images, etc.) on a display unit, a touch panel function, a function to display a calendar, date, or time, a function to control processing using various software (programs), a wireless communication function, a function to connect to various computer networks using the wireless communication function, a function to send or receive various data using the wireless communication function, a function to read programs or data recorded on a recording medium and display them on a display unit, etc. Furthermore, electronic devices having multiple display units can have a function to primarily display image information on one display unit and primarily display text information on another display unit, or a function to display a stereoscopic image by displaying images taking parallax into account on multiple display units, etc. Furthermore, electronic devices having an image receiving unit can have a function to capture still images, a function to capture videos, a function to automatically or manually correct captured images, a function to save captured images on a recording medium (external or built-in to the camera), a function to display captured images on a display unit, etc. Note that the functions that the electronic devices shown in FIGS. 8A to 8F can have are not limited to these, and various other functions can be included.

[0158] FIG. 8G shows a wristwatch-type mobile information terminal, which can be used as, for example, a smartwatch. This wristwatch-type mobile information terminal includes a housing 7000, a display unit 7001, operation buttons 7022 and 7023, a connection terminal 7024, a band 7025, a microphone 7026, a sensor 7029, a speaker 7030, and the like. The display surface of the display unit 7001 is curved, and a display can be performed along the curved display surface. This mobile information terminal is also capable of hands-free communication through mutual communication with, for example, a wireless headset. Note that the connection terminal 7024 allows mutual data transmission with another information terminal and charging. Charging can also be performed by wireless power supply.

[0159] A display unit 7001 mounted on a housing 7000 that also serves as a bezel has a non-rectangular display area. The display unit 7001 can display an icon 7027 indicating the time, other icons 7028, and the like. The display unit 7001 may also be a touch panel (input / output device) equipped with a touch sensor (input device).

[0160] 8G can have various functions, such as a function to display various information (still images, videos, text images, etc.) on the display, a touch panel function, a function to display a calendar, date, or time, a function to control processing using various software (programs), a wireless communication function, a function to connect to various computer networks using the wireless communication function, a function to send or receive various data using the wireless communication function, a function to read out programs or data recorded on a recording medium and display it on the display, etc.

[0161] The housing 7000 may also have a speaker, sensors (including those with the function of measuring force, displacement, position, velocity, acceleration, angular velocity, rotation speed, distance, light, liquid, magnetism, temperature, chemical substances, sound, time, hardness, electric field, current, voltage, power, radiation, flow rate, humidity, gradient, vibration, odor, or infrared rays), a microphone, etc. inside.

[0162] Note that the light-emitting device which is one embodiment of the present invention can be used in each display portion of the electronic devices described in this embodiment, and the electronic devices can have a long lifetime.

[0163] 9A to 9C are examples of electronic devices to which a light-emitting device is applied. FIG. 9A shows a portable information terminal 9310 in an unfolded state. FIG. 9B shows the portable information terminal 9310 in a state in which it is changing from an unfolded state to a folded state. FIG. 9C shows the portable information terminal 9310 in a folded state. The portable information terminal 9310 has excellent portability in a folded state, and has excellent display visibility due to a seamless, wide display area in an unfolded state.

[0164] The display portion 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display portion 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). The display portion 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 hinges 9313. Note that the light-emitting device of one embodiment of the present invention can be used for the display portion 9311. Furthermore, an electronic device with a long life can be realized. A display region 9312 in the display portion 9311 is a display region located on a side surface of the portable information terminal 9310 in the folded state. Information icons, shortcuts of frequently used applications or programs, and the like can be displayed in the display region 9312, allowing the user to smoothly check information and start applications.

[0165] 10A and 10B show automobiles to which the light-emitting device is applied. That is, the light-emitting device can be provided integrally with the automobile. Specifically, the light-emitting device can be applied to the exterior lights 5101 (including the rear of the vehicle), tire wheels 5102, and part or all of the doors 5103 of the automobile shown in FIG. 10A. The light-emitting device can also be applied to the interior display unit 5104, steering wheel 5105, shift lever 5106, seat 5107, inner rearview mirror 5108, windshield 5109, and the like shown in FIG. 10B. It may also be applied to parts of other glass windows.

[0166] In this manner, an electronic device or an automobile to which the light-emitting device according to one embodiment of the present invention is applied can be obtained. In this case, the electronic device can have a long lifetime. The applicable electronic device or automobile is not limited to those described in this embodiment, and can be applied in any field.

[0167] Note that the structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiment modes.

[0168] (Fourth embodiment) In this embodiment, a lighting device manufactured using a light-emitting device which is one embodiment of the present invention or a light-emitting device which is a part of the light-emitting device, and its application examples will be described. Note that the structure of the lighting device will be described with reference to FIG.

[0169] 11A and 11B show examples of cross-sectional views of lighting devices. Fig. 11A shows a bottom-emission lighting device that extracts light on the substrate side, and Fig. 11B shows a top-emission lighting device that extracts light on the sealing substrate side.

[0170] 11A includes a light-emitting device 4002 on a substrate 4001. The substrate 4001 also includes a substrate 4003 having an uneven surface on the outer surface thereof. The light-emitting device 4002 includes a first electrode 4004, an EL layer 4005, and a second electrode 4006.

[0171] The first electrode 4004 is electrically connected to an electrode 4007, and the second electrode 4006 is electrically connected to an electrode 4008. An auxiliary wiring 4009 may be provided to be electrically connected to the first electrode 4004. An insulating layer 4010 is formed over the auxiliary wiring 4009.

[0172] The substrate 4001 and the sealing substrate 4011 are bonded together with a sealant 4012. A desiccant 4013 is preferably provided between the sealing substrate 4011 and the light-emitting device 4002. The substrate 4003 has projections and recesses as shown in FIG. 11A, which can improve the extraction efficiency of light generated in the light-emitting device 4002.

[0173] 11B includes a light-emitting device 4202 on a substrate 4201. The light-emitting device 4202 includes a first electrode 4204, an EL layer 4205, and a second electrode 4206.

[0174] The first electrode 4204 is electrically connected to the electrode 4207, and the second electrode 4206 is electrically connected to the electrode 4208. An auxiliary wiring 4209 may be provided to be electrically connected to the second electrode 4206. An insulating layer 4210 may be provided under the auxiliary wiring 4209.

[0175] The substrate 4201 and a sealing substrate 4211 having an uneven surface are bonded with a sealant 4212. A barrier film 4213 and a planarization film 4214 may be provided between the sealing substrate 4211 and the light-emitting device 4202. Note that the sealing substrate 4211 has unevenness as shown in FIG. 11B, which can improve the extraction efficiency of light generated in the light-emitting device 4202.

[0176] An example of an application of these lighting devices is a ceiling light for indoor lighting. Ceiling lights include direct ceiling-mounted lights and ceiling-embedded lights. Such lighting devices are constructed by combining a light-emitting device with a housing and a cover.

[0177] Other applications include footlights that can illuminate the floor and increase safety around the feet. Footlights are effective for use in bedrooms, staircases, and corridors, for example. In such cases, the size and shape can be adjusted appropriately depending on the size and structure of the room. Furthermore, a stationary lighting device can be created by combining a light-emitting device with a support base.

[0178] It can also be used as a sheet-type lighting device (sheet lighting). Sheet lighting is attached to a wall surface, so it does not take up much space and can be used for a wide range of purposes. It can also be easily made into a large-area product. It can also be used on curved walls and housings.

[0179] In addition to the above, a lighting device having a function as furniture can be obtained by applying the light-emitting device according to one embodiment of the present invention or a light-emitting device that is a part of the light-emitting device to a part of furniture installed in a room. As described above, various lighting devices using the light-emitting device according to one embodiment of the present invention can be obtained.

[0180] Furthermore, examples of applications manufactured by applying the light-emitting device according to one embodiment of the present invention or a light-emitting device that is a part thereof include a light source for a face recognition sensor, a light source for fingerprint recognition, a light source for a motion sensor in a dark place, a light source for a human vein sensor, a light source for a sensor that measures a saturated blood oxygen concentration of a living body, a light source for a sensor that measures the concentration of oxygenated hemoglobin, etc. Other application examples that make use of the features of the light-emitting device according to one embodiment of the present invention or a light-emitting device that is a part thereof are also included in one embodiment of the present invention.

[0181] The structure described in this embodiment mode can be used in appropriate combination with structures described in other embodiments. [Example]

[0182] In this example, light-emitting devices according to one embodiment of the present invention were fabricated, and the device characteristics are described. Light-emitting device 1 fabricated in this example has a microcavity structure adjusted to emit light having a maximum peak wavelength of about 800 nm in its emission spectrum, and light-emitting device 2 has a microcavity structure adjusted to emit light having a maximum peak wavelength of about 855 nm in its emission spectrum.

[0183] The specific element structure of the above-mentioned light-emitting device and its manufacturing method will be described below. The element structure of the light-emitting device described in this example is shown in Figure 12, and the specific configuration is shown in Table 2. The chemical formulas of the materials used in this example are shown below.

[0184] [Table 2]

[0185] [ka]

[0186] <Fabrication of light-emitting devices> <Fabrication of Light-Emitting Device 1 and Light-Emitting Device 2> The light-emitting device shown in this example has a structure in which a hole injection layer 911, a hole transport layer 912, a light-emitting layer 913, an electron transport layer 914, and an electron injection layer 915 are sequentially stacked on a first electrode 901 formed on a substrate 900, as shown in Figure 12, and a second electrode 903 is stacked on the electron injection layer 915.

[0187] First, a first electrode 901 was formed on a substrate 900. The electrode area was 4 mm 2The dimensions were 2 mm x 2 mm. A glass substrate was used for the substrate 900. The first electrode 901 was formed by forming a reflective electrode from an alloy film of silver (Ag), palladium (Pd), and copper (Cu) (Ag-Pd-Cu (APC) film) with a thickness of 100 nm by sputtering, and then forming a transparent electrode from indium tin oxide containing silicon oxide (ITSO) with a thickness of 10 nm by sputtering.

[0188] Here, as a pretreatment, the surface of the substrate was washed with water, baked at 200°C for 1 hour, and then subjected to UV ozone treatment for 370 seconds. -4 The substrate was introduced into a vacuum deposition apparatus whose internal pressure had been reduced to about Pa, and after vacuum baking at 170°C for 30 minutes in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0189] Next, a hole injection layer 911 was formed on the first electrode 901. The hole injection layer 911 was formed by evaporating 1×10 -4 After reducing the pressure to 10 Pa, 1,3,5-tri(dibenzothiophen-4-yl)benzene (abbreviation: DBT3P-II) and molybdenum oxide were co-evaporated at a mass ratio of DBT3P-II:molybdenum oxide = 2:1 to form a film having a thickness of 25 nm for light-emitting device 1 and a thickness of 30 nm for light-emitting device 2.

[0190] Next, a hole transport layer 912 was formed on the hole injection layer 911. The hole transport layer 912 was formed by vapor deposition using N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine (abbreviation: PCBBiF) to a thickness of 20 nm.

[0191] Next, a light-emitting layer 913 was formed on the hole-transporting layer 912 .

[0192] The light-emitting layer 913 contains 2-[3′-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II) and PCBBiF, as well as bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-2-benzo[g]quinoxalinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κC) as a guest material (phosphorescent light-emitting material). 2 Iridium(III) (abbreviated as [Ir(dmdpbq)2(dpm)]) was co-deposited at a weight ratio of 2mDBTBPDBq-II:PCBBiF:[Ir(dmdpbq)2(dpm)] = 0.7:0.3:0.1. The film thickness was 40 nm.

[0193] Next, an electron transport layer 914 was formed on the light emitting layer 913 .

[0194] The electron transport layer 914 was formed by evaporating the electron transport material 2mDBTBPDBq-II to a thickness of 20 nm, and then evaporating the electron transport material 2,9-bis(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBPhen) to a thickness of 75 nm for light-emitting device 1 and 85 nm for light-emitting device 2.

[0195] Next, an electron injection layer 915 was formed on the electron transport layer 914. The electron injection layer 915 was formed by vapor deposition using lithium fluoride (LiF) so as to have a film thickness of 1 nm.

[0196] Next, a second electrode 903 was formed on the electron injection layer 915. The second electrode 903 was formed by vapor deposition of silver (Ag) and magnesium (Mg) in a volume ratio of 1:0.1 and with a film thickness of 30 nm. In this example, the second electrode 903 functions as a cathode and is a semi-transparent / semi-reflective electrode that has the functions of reflecting and transmitting light. The light-emitting device shown in this example is a top-emission type light-emitting device that extracts light from the second electrode 903. Furthermore, an organic capping layer 904 was formed on the second electrode 903 to improve extraction efficiency. The organic capping layer 904 is preferably made of a material with a refractive index of 1.7 or higher; here, DBT3P-II was formed by vapor deposition to a thickness of 100 nm.

[0197] Through the above steps, a light-emitting device including an EL layer sandwiched between a pair of electrodes was formed over the substrate 900. Note that the hole injection layer 911, the hole transport layer 912, the light-emitting layer 913, the electron transport layer 914, and the electron injection layer 915 described in the above steps are functional layers that constitute the EL layer in one embodiment of the present invention. Furthermore, in all of the evaporation steps in the above-described manufacturing method, evaporation was performed using a resistance heating method.

[0198] The light-emitting device fabricated as described above is sealed with another substrate (not shown). When sealing using another substrate (not shown), another substrate (not shown) coated with a sealant that hardens when exposed to ultraviolet light is fixed on the substrate 900 in a glove box with a nitrogen atmosphere, and the substrates are bonded together so that the sealant adheres to the periphery of the light-emitting device formed on the substrate 900. During sealing, 365 nm ultraviolet light is applied at 6 J / cm. 2 The sealant was solidified by irradiation and then stabilized by heat treatment at 80°C for 1 hour.

[0199] <Operating characteristics of light-emitting devices> The operating characteristics of each light-emitting device were measured. The measurements were carried out at room temperature (an atmosphere maintained at 25°C). The current density-radiant emittance characteristics of each light-emitting device are shown in Figure 13, the voltage-current density characteristics in Figure 14, the current density-external quantum efficiency characteristics in Figure 15, and the voltage-radiant emittance characteristics in Figure 16. Table 3 below shows the results when the current density was 10 mA / cm 2 The main initial characteristic values ​​of each light-emitting device in the vicinity are shown below. Note that the radiant emittance, radiant flux, and external quantum efficiency were calculated using radiance, assuming that the light distribution characteristics of the device are Lambertian.

[0200] [Table 3]

[0201] In addition, each light-emitting device is supplied with 10 mA / cm 2 Figure 17 shows the EL emission spectra when a current was passed through the device at a current density of 1000 nm. A near-infrared spectroradiometer (SR-NIR, manufactured by Topcon Corporation) was used to measure the emission spectra. In Figure 17, each light-emitting device derives its emission from the organometallic complex [Ir(dmdpbq)2(dpm)] contained in the light-emitting layer 913, which has an emission peak wavelength of approximately 800 nm. However, because each light-emitting device has an optically tuned structure, Light-emitting Device 1 has an emission peak near 800 nm, and Light-emitting Device 2 has an emission peak near 855 nm. Each light-emitting device exhibits a line-narrowed EL emission spectrum due to the microcavity effect. The emission spectrum of the organometallic complex [Ir(dmdpbq)2(dpm)] is shown in Figure 18. The emission spectrum was measured using an absolute PL quantum yield measurement device (C11347-01, manufactured by Hamamatsu Photonics K.K.) at room temperature under a nitrogen atmosphere with a deoxygenated dichloromethane solution (0.010 mmol / L) placed in a quartz cell, which was then sealed.

[0202] 14 and 16, it can be seen that each light-emitting device is driven at a low voltage, and FIG. 15 shows that each light-emitting device emits light with high efficiency.

[0203] Light-emitting device 1 exhibits light emission with a strong peak intensity and particularly high luminous efficiency. Thus, one embodiment of the present invention provides a light-emitting device with a strong peak intensity and high luminous efficiency. Furthermore, light-emitting device 2 exhibits an EL emission spectrum with a peak wavelength longer than the emission peak wavelength of the organometallic complex [Ir(dmdpbq)2(dpm)] contained in light-emitting layer 913. Thus, one embodiment of the present invention provides a light-emitting device exhibiting an emission EL spectrum with a peak wavelength longer than the emission peak wavelength of the light-emitting substance.

[0204] In addition, each light-emitting device is supplied with 2.5mA / cm 3 The viewing angle dependence of the EL emission spectrum when a current was passed at a current density of 100 s is shown in Fig. 19. The EL emission spectrum was measured using a PMA-12 (manufactured by Hamamatsu Photonics KK).

[0205] 19, it was confirmed that light-emitting device 1 exhibited the strongest emission peak intensity when measured from the front (0°), and that the emission peak intensity tended to weaken as the angle increased from the front (0°) to the side (90°). On the other hand, it was confirmed that light-emitting device 2 tended to exhibit the greatest emission peak intensity when measured from an angle of 40° to the side rather than from the front (0°).

[0206] Furthermore, when the photon number ratio relative to the Lambertian was calculated from the EL emission spectra shown in Figure 19, it was 39.3% for Light-emitting Device 1 and 108.4% for Light-emitting Device 2. By multiplying this photon number ratio by the external quantum efficiency assumed for the Lambertian type shown in Table 3, accurate external quantum efficiency values ​​taking the viewing angle into account were obtained: 3.9% for Light-emitting Device 1 and 6.1% for Light-emitting Device 2. Therefore, from the relationship between the external quantum efficiency assumed for the Lambertian type and the external quantum efficiency taking the viewing angle into account, it can be seen that Light-emitting Device 1 has a stronger emission intensity when viewed from the front, and Light-emitting Device 2 has a stronger emission intensity in terms of total luminous flux.

[0207] The refractive index of DBT3P-II used in the organic cap layer 904 was measured at room temperature using a rotary compensator type multi-angle high-speed spectroscopic ellipsometer (M-2000U) manufactured by JA Woolam Corp. As a result, the ordinary refractive index (ordinary) of DBT3P-II at a wavelength of 633 nm was 1.80, and the extraordinary refractive index (extraordinary) was 1.73.

[0208] Furthermore, reliability tests were conducted on the light-emitting devices 1 and 2. The measurement results are shown in Figure 20. In Figure 20, the vertical axis represents the normalized intensity (%) when the initial light-emitting intensity is taken as 100%, and the horizontal axis represents the device operation time (h). The reliability tests were conducted at a current density of 75 mA / cm 2 The light-emitting device was driven.

[0209] The results of the reliability test showed that both light-emitting devices 1 and 2 exhibited high reliability. This is due to the effect of using an organometallic complex, [Ir(dmdpbq)2(dpm)], which emits light in the near-infrared region and has a stable excited state, in the light-emitting layer of the light-emitting device.

[0210] (Reference synthesis example 1) In this Reference Synthesis Example, the organometallic complex used in Example 1, bis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-2-benzo[g]quinoxalinyl-κN]phenyl-κC}(2,2,6,6-tetramethyl-3,5-heptanedionato-κN) 2 This article describes a method for synthesizing (O,O') iridium(III) (abbreviation: [Ir(dmdpbq)2(dpm)]).

[0211] [ka]

[0212] <Step 1: Synthesis of 2,3-bis-(3,5-dimethylphenyl)-2-benzo[g]quinoxaline (abbreviation: Hdmdpbq)> First, Hdmdpbq was synthesized. 3.20 g of 3,3',5,5'-tetramethylbenzyl, 1.97 g of 2,3-diaminonaphthalene, and 60 mL of ethanol were placed in a three-necked flask equipped with a reflux condenser. After replacing the atmosphere with nitrogen, the mixture was stirred at 90°C for 7.5 hours. After the specified time had elapsed, the solvent was distilled off. The product was then purified by silica gel column chromatography using toluene as the developing solvent to obtain the target product (yellow solid, yield 3.73 g, 79%). The synthesis scheme for Step 1 is shown in (a-1).

[0213] [ka]

[0214] Nuclear magnetic resonance spectroscopy of the yellow solid obtained in step 1 ( 1 The results of the analysis by H-NMR are shown below. From these results, it was found that Hdmdpbq was obtained.

[0215] of the obtained material 1 The 1 H NMR data is shown below. 1 H-NMR.δ(CD2Cl2):2.28(s,12H),7.01(s,2H),7.16(s,4H),7.56-7.58(m,2H),8.11-8.13(m,2H),8.74(s,2H).

[0216] Step 2: Synthesis of di-μ-chloro-tetrakis{4,6-dimethyl-2-[3-(3,5-dimethylphenyl)-2-benzo[g]quinoxalinyl-κN]phenyl-κC}diiridium(III) (abbreviation: [Ir(dmdpbq)Cl]) Next, 15 mL of 2-ethoxyethanol, 5 mL of water, 1.81 g of Hdmdpbq obtained in Step 1, and 0.66 g of iridium chloride hydrate (IrCl3·H2O) (Furuya Metal Co., Ltd.) were placed in a recovery flask equipped with a reflux condenser, and the atmosphere inside the flask was replaced with argon. The reaction was then carried out by irradiating with microwaves (2.45 GHz, 100 W) for 2 hours. After the specified time had elapsed, the resulting residue was suction filtered and washed with methanol to obtain the target product (black solid, 1.76 g, 81% yield). The synthesis scheme for Step 2 is shown in (a-2).

[0217] [ka]

[0218] Step 3: Synthesis of [Ir(dmdpbq)2(dpm)] Next, 20 mL of 2-ethoxyethanol, 1.75 g of [Ir(dmdpbq)Cl] obtained in step 2, 0.50 g of dipivaloylmethane (abbreviation: Hdpm), and 0.95 g of sodium carbonate were placed in a recovery flask equipped with a reflux condenser, and the atmosphere in the flask was replaced with argon. After that, microwave irradiation (2.45 GHz, 100 W) was performed for 3 hours.

[0219] The resulting residue was suction filtered with methanol and then washed with water and methanol. The resulting solid was purified by silica gel column chromatography using dichloromethane as a developing solvent and then recrystallized in a mixed solvent of dichloromethane and methanol to obtain the target product (dark green solid, yield 0.42 g, 21% yield). 0.41 g of the resulting dark green solid was purified by train sublimation. The conditions for sublimation purification were a pressure of 2.7 Pa and argon gas flow at a flow rate of 10.5 mL / min while heating the dark green solid to 300°C. After sublimation purification, a dark green solid was obtained in 78% yield. The synthesis scheme for Step 3 is shown in (a-3).

[0220] [ka]

[0221] Nuclear magnetic resonance spectroscopy of the dark green solid obtained in step 3 ( 1 The results of the analysis by H-NMR are shown below. From these results, it was found that [Ir(dmdpbq)2(dpm)] was obtained.

[0222] of the obtained material 1 The 1 H NMR data is shown below. 1 H-NMR.δ(CD2Cl2):0.75(s,18H),0.97(s,6H),2.01(s,6H),2.52(s,12H),4.86(s,1H),6.39(s,2H),7.15 (s,2H),7.31(s,2H),7.44-7.51(m,4H),7.80(d,2H),7.86(s,4H),8.04(d,2H),8.42(s,2H),8.58(s,2H). [Explanation of symbols]

[0223] 101: first electrode, 102: second electrode, 103: EL layer, 103a, 103b: EL layer, 104: charge generation layer, 105: organic cap layer, 111, 111a, 111b: hole injection layer, 112, 112a, 112b: hole transport layer, 113, 113a, 113b: light emitting layer, 114, 114a, 114b: electron transport layer, 115, 115a, 115b: electron injection layer, 200R, 200G, 200B: optical path, 201: first substrate, 202: transistor (FET), 203R, 203G, 203B, 203W: light emitting device, 204: EL layer, 205: second the substrate, 206R, 206G, 206B: color filters, 206R', 206G', 206B': color filters, 207: first electrode, 208: second electrode, 209: black layer (black matrix), 210R, 210G: conductive layer, 301: first substrate, 302: pixel section, 303: drive circuit section (source line drive circuit), 304a, 304b: drive circuit section (gate line drive circuit), 305: seal material, 306: second substrate, 307: routing wiring, 308: FPC, 309: FET, 310: FET, 311: FET, 312: FET, 313: first electrode electrode, 314: insulator, 315: EL layer, 316: second electrode, 317: light-emitting device, 318: space, 900: substrate, 901: first electrode, 902: EL layer, 903: second electrode, 904: organic cap layer, 911: hole injection layer, 912: hole transport layer, 913: light-emitting layer, 914: electron transport layer, 915: electron injection layer, 4000: lighting device, 4001: substrate, 4002: light-emitting device, 4003: substrate, 4004: first electrode, 4005: EL layer, 4006: second electrode, 4007: electrode, 4008: electrode, 4009: auxiliary wiring, 4010: insulating layer, 4011 : sealing substrate, 4012: sealing material, 4013: desiccant, 4200: lighting device, 4201: substrate, 4202: light-emitting device, 4204: first electrode, 4205: EL layer, 4206: second electrode, 4207: electrode, 4208: electrode, 4209: auxiliary wiring, 4210: insulating layer, 4211: sealing substrate, 4212: sealing material, 4213: barrier film, 4214: planarization film, , 5101: light, 5102: wheel, 5103: door, 5104: display unit, 5105: steering wheel, 5106: shift lever, 5107: seat, 5108: inner rearview mirror,5109: Windshield, 7000: Housing, 7001: Display unit, 7002: Second display unit, 7003: Speaker, 7004: LED lamp, 7005: Operation keys, 7006: Connection terminal, 7007: Sensor, 7008: Microphone, 7009: Switch, 7010: Infrared port, 7011: Recording medium reading unit, 7014: Antenna, 7015: Shutter switch button, 7016: image receiving unit, 7018: stand, 7022, 7023: operation buttons, 7024: connection terminal, 7025: band, 7026: microphone, 7029: sensor, 7030: speaker, 7052, 7053, 7054: information, 9310: mobile information terminal, 9311: display unit, 9312: display area, 9313: hinge, 9315: housing,

Claims

[Claim 1] 1. A light-emitting device having a light-emitting layer between a first electrode and a second electrode, the first electrode has a structure in which a reflective electrode and a transparent electrode are stacked, the second electrode is a semi-transmissive semi-reflective electrode, the reflective electrode, or both the reflective electrode and the second electrode, are made of an electrode material that exhibits a reflectance of 90% or more for light having a wavelength of 850 nm; the reflective electrode, or both the reflective electrode and the second electrode, comprises at least one of gold (Au), silver (Ag), and copper (Cu); the second electrode has a thickness of 30 nm or more and 60 nm or less; the light-emitting layer contains a light-emitting substance having an emission peak in a wavelength range of 750 nm or more and 1000 nm or less, The light-emitting device has an emission peak at a wavelength longer than that of the light-emitting substance.

Images