Organic semiconductor device, organic el device, light-emitting apparatus, electronic equipment, and lighting apparatus

Abstract

To suppress an increase in a voltage in an organic semiconductor device having a step of forming an aluminum oxide film on an organic semiconductor layer.SOLUTION: An organic semiconductor device includes a first electrode, a second electrode, an organic semiconductor layer, and a buffer layer, and the organic semiconductor layer is positioned between the first electrode and the second electrode, the buffer layer is positioned between the organic semiconductor layer and the second electrode, and the side surface of the organic semiconductor layer and the side surface of the buffer layer have substantially the same surface.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Organic EL devices (organic EL elements) that utilize electroluminescence (EL) using organic compounds are becoming more and more practical. The basic structure of these organic EL devices is a pair of electrodes sandwiching an organic compound layer (EL layer) containing a light-emitting material between them. By applying a voltage to this device, carriers are injected, and the recombination energy of these carriers is utilized to emit light from the light-emitting material.

[0003] Because such organic EL devices are self-luminous, when used as display pixels, they offer advantages such as higher visibility and no need for backlighting compared to liquid crystal displays, making them particularly suitable for flat panel displays. Another major advantage of displays using such organic EL devices is that they can be fabricated to be thin and lightweight. Another feature is their extremely fast response time.

[0004] Furthermore, these organic EL devices can emit light continuously in two dimensions, making it possible to obtain surface light emission. This is a feature that is difficult to obtain with point light sources such as incandescent bulbs and LEDs, or linear light sources such as fluorescent lamps, making them highly useful as surface light sources for lighting applications.

[0005] Thus, light-emitting devices using organic EL devices are suitable for a variety of electronic devices, but research and development is ongoing to find organic EL devices with even better characteristics.

[0006] In order to obtain a light-emitting device with higher resolution using an organic EL device, research is being conducted into patterning of organic layers by photolithography using photoresist, etc., instead of vapor deposition using a metal mask. By using photolithography, a high-resolution light-emitting device with an EL layer spacing of several μm can be obtained (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2018-521459 Summary of the Invention [Problem to be solved by the invention]

[0008] When patterning an organic layer by photolithography, an aluminum oxide film may be used as a mask layer for the organic layer. Aluminum oxide films are suitable as mask layers for organic layers because they are less likely to cause significant damage to the organic layer during deposition or removal. However, even though they are less susceptible to significant damage, prolonged exposure of the surface of the organic layer to the processing conditions used to remove the aluminum oxide film can lead to deterioration of the organic layer. On the other hand, if the aluminum oxide film remains on the surface of the organic layer, it may result in a higher voltage for the subsequently fabricated device.

[0009] Therefore, an object of one embodiment of the present invention is to suppress an increase in voltage in an organic semiconductor device having a step of forming an aluminum oxide film in contact with an organic semiconductor layer, or to provide an organic semiconductor device having good characteristics in an organic semiconductor device having a step of forming an aluminum oxide film in contact with an organic semiconductor layer. [Means for solving the problem]

[0010] One aspect of the present invention is an organic semiconductor device having a first electrode, a second electrode, a first organic semiconductor layer, and a buffer layer, wherein the first organic semiconductor layer is located between the first electrode and the second electrode, the buffer layer is located between the first organic semiconductor layer and the second electrode, and a side surface of the first organic semiconductor layer and a side surface of the buffer layer are approximately flush with each other.

[0011] Another embodiment of the present invention is an organic semiconductor device having the above structure, wherein the buffer layer contains a metal.

[0012] Another embodiment of the present invention is an organic semiconductor device having the above structure, in which the buffer layer contains an organometallic compound.

[0013] Another embodiment of the present invention is an organic semiconductor device in which, in each of the above structures, the buffer layer contains an organic compound.

[0014] Another aspect of the present invention is an organic semiconductor device having any of the above structures, wherein the buffer layer is formed by laminating a first buffer layer and a second buffer layer.

[0015] Another embodiment of the present invention is an organic semiconductor device having any of the above structures, which further includes a second organic semiconductor layer, which is located between the buffer layer and the second electrode, and whose side surface is not flush with the side surface of the first organic semiconductor layer and the side surface of the buffer layer.

[0016] Another embodiment of the present invention is an organic EL device comprising a first electrode, a second electrode, a first organic semiconductor layer, and a buffer layer, wherein the first organic semiconductor layer has an emitting layer, the first organic semiconductor layer is located between the first electrode and the second electrode, the buffer layer is located between the first organic semiconductor layer and the second electrode, and a side surface of the first organic semiconductor layer and a side surface of the buffer layer are on approximately the same surface.

[0017] Another embodiment of the present invention is an organic EL device having the above structure, wherein the buffer layer contains a metal.

[0018] Another embodiment of the present invention is an organic EL device having the above structure, wherein the buffer layer contains an organometallic compound.

[0019] Another aspect of the present invention is an organic EL device having any of the above structures, wherein the buffer layer contains an organic compound.

[0020] Another aspect of the present invention is an organic EL device having any of the above configurations, wherein the buffer layer is formed by laminating a first buffer layer and a second buffer layer.

[0021] Another embodiment of the present invention is an organic EL device having any of the above structures, further comprising a second organic semiconductor layer, the second organic semiconductor layer being located between the buffer layer and the second electrode, and the side surface of the second organic semiconductor layer not being flush with the side surface of the first organic semiconductor layer and the side surface of the buffer layer.

[0022] Another embodiment of the present invention is a light-emitting device including the organic EL device having any of the above structures and a transistor or a substrate.

[0023] Another embodiment of the present invention is an electronic device including a light-emitting device having any of the above structures and a detection unit, an input unit, or a communication unit.

[0024] Another embodiment of the present invention is a lighting device including a light-emitting device having any of the above structures and a housing.

[0025] In this specification, the term "light-emitting device" includes an image display device using an organic EL device. The term "light-emitting device" may also include a module in which a connector, such as an anisotropic conductive film or TCP (Tape Carrier Package), is attached to an organic EL device, a module in which a printed wiring board is provided at the end of the TCP, or a module in which an IC (integrated circuit) is directly mounted on an organic EL device using a COG (Chip On Glass) method. Furthermore, lighting fixtures and the like may include a light-emitting device. [Effects of the Invention]

[0026] In one embodiment of the present invention, in an organic semiconductor device having a processing step by photolithography on an organic semiconductor layer, damage to the organic semiconductor layer during processing by photolithography can be suppressed, and an increase in voltage of the organic semiconductor device can be suppressed. Alternatively, in one embodiment of the present invention, in an organic semiconductor device having a processing step by photolithography on an organic semiconductor layer, damage to the organic semiconductor layer during processing by photolithography can be suppressed, and an organic semiconductor device with good characteristics can be provided.

[0027] 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]

[0028] [Figure 1] 1A to 1C illustrate an organic semiconductor device according to one embodiment of the present invention. [Figure 2] 2(A) and 2(B) are diagrams illustrating an organic semiconductor device. [Figure 3] 3(A) to 3(C) are diagrams showing conventional configurations of membranes. [Figure 4] 4(A) to 4(E) are diagrams showing a film processing method. [Figure 5] 5(A) to 5(D) are diagrams showing a film processing method. [Figure 6] 6(A) to 6(D) are diagrams showing a light emitting device. [Figure 7] FIG. 7 is a diagram illustrating a light emitting device. [Figure 8] 8(A) to 8(F) are diagrams showing a method for fabricating an organic EL device and a light-emitting device. [Figure 9] 9(A) to 9(F) are diagrams illustrating a method for fabricating an organic EL device and a light-emitting device. [Figure 10] FIG. 10 is a diagram showing an organic EL device. [Figure 11] 11(A) and 11(B) are diagrams showing an active matrix light emitting device. [Figure 12] 12(A) and 12(B) are diagrams showing an active matrix light emitting device. [Figure 13] FIG. 13 is a diagram showing an active matrix light emitting device. [Figure 14] 14A to 14D are diagrams showing electronic devices. [Figure 15] 15(A) to 15(C) are diagrams showing electronic devices. [Figure 16] FIG. 16 is a diagram showing an in-vehicle display device and a lighting device. [Figure 17] 17(A) and 17(B) are diagrams showing electronic devices. [Figure 18] 18(A) to 18(C) are diagrams showing electronic devices. [Figure 19] FIG. 19 shows the luminance-current density characteristics of the light-emitting device 1. [Figure 20] FIG. 20 shows the current efficiency-luminance characteristics of the light-emitting device 1. [Figure 21] FIG. 21 shows the luminance-voltage characteristics of the light-emitting device 1. [Figure 22] FIG. 22 shows the current-voltage characteristics of the light-emitting device 1. [Figure 23] FIG. 23 shows the emission spectrum of the light-emitting device 1. [Figure 24] FIG. 24 is a graph showing the change in luminance with respect to the driving time of the light-emitting device 1. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0029] 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 it will be readily understood by those skilled in the art that various changes in form and details can be made 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.

[0030] In this specification, etc., a device fabricated using a metal mask or an FMM (fine metal mask, high-resolution metal mask) may be referred to as a device with an MM (metal mask) structure. In addition, in this specification, etc., a device fabricated without using a metal mask or an FMM may be referred to as a device with an MML (metal maskless) structure.

[0031] Furthermore, in this specification and the like, a film that has not undergone shape processing after deposition is generally referred to as a "film," and a film that has undergone shape processing is generally referred to as a "layer." However, these terms are used solely for the purpose of making it easier to understand the progress of the process, and there is no significant difference between them, so "film" can be read as a "layer" and "layer" as a "film." In particular, when describing a film that has not undergone a processing step, both terms are considered to have the same meaning.

[0032] (Embodiment 1) In this embodiment, an organic semiconductor device according to one embodiment of the present invention will be described.

[0033] 1A to 1C show a structure of an organic semiconductor device 100, which is an example of an organic semiconductor device according to one embodiment of the present invention.

[0034] As shown in FIG. 1(A), the organic semiconductor device 100 has a first electrode 101 and a second electrode 102 provided on an insulating layer 160, an organic semiconductor layer 151 sandwiched between the first electrode 101 and the second electrode 102, and a buffer layer 152 sandwiched between the organic semiconductor layer 151 and the second electrode 102.

[0035] Both the organic semiconductor layer 151 and the buffer layer 152 are layers processed by photolithography in the manufacturing process of the organic semiconductor device 100. Therefore, the side surfaces (ends) of the organic semiconductor layer 151 and the side surfaces (ends) of the buffer layer 152 are substantially flush with each other. In other words, the side surfaces (ends) of the organic semiconductor layer 151 and the side surfaces (ends) of the buffer layer 152 are located on substantially the same plane.

[0036] The buffer layer 152 is a layer for protecting the organic semiconductor layer 151 in the manufacturing process of the organic semiconductor device 100. By forming the buffer layer 152, damage to the organic semiconductor layer 151 can be suppressed, and the organic semiconductor device 100 can be prevented from being subjected to high voltage. As a result, it is possible to realize an organic semiconductor device with ultra-high definition and excellent characteristics that has been processed by photolithography. Processing by photolithography will be described in detail in Embodiment 2.

[0037] Materials that can be used for the buffer layer 152 include materials that are heat-resistant or stable. Furthermore, it is preferable to use a material that is unlikely to significantly deteriorate device characteristics (e.g., increase in voltage) when the buffer layer 152 is provided between the organic semiconductor layer 151 and the second electrode 102. Furthermore, when light generated in the organic semiconductor layer 151 is emitted from the second electrode 102 side, it is preferable to use a material that satisfies the above-mentioned conditions and provides a desired transmittance (e.g., a transmittance of preferably 40% or more, more preferably a transmittance of 50% or more) for the buffer layer 152. Examples of materials that are heat-resistant or stable, unlikely to significantly deteriorate device characteristics, and provide a desired transmittance include metals, organometallic compounds, and organic compounds with electron transport properties.

[0038] Examples of metals that can be used include aluminum (Al), titanium (Ti), vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), gallium (Ga), germanium (Ge), zinc (Zn), indium (In), tin (Sn), molybdenum (Mo), tantalum (Ta), tungsten (W), palladium (Pd), gold (Au), platinum (Pt), silver (Ag), yttrium (Y), neodymium (Nd), zirconium (Zr), europium (Eu), and ytterbium (Yb), as well as alloys containing appropriate combinations of these metals. 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)) that are not listed above, rare earth metals such as rubidium (Rb) and magnesium (Mg), and alloys containing appropriate combinations of these, as well as graphene.

[0039] As the organometallic compound, for example, a phthalocyanine-based complex compound such as copper phthalocyanine (abbreviated as CuPc) or zinc phthalocyanine (abbreviated as ZnPc) can be used.

[0040] In addition, organometallic compounds such as tris(8-quinolinolato)aluminum(III) (abbreviation: Alq3), tris(4-methyl-8-quinolinolato)aluminum(III) (abbreviation: Almq3), 8-quinolinolatolithium(I) (abbreviation: Liq), bis(10-hydroxybenzo[h]quinolinato)beryllium(II) (abbreviation: BeBq2), and bis(2-methyl-8-quinolinolato)(4-phenylphenolato)alum(II) were also used. Examples of usable complexes include metal complexes having a quinoline ring or a benzoquinoline ring, such as aluminum(III) (abbreviation: BAlq) and bis(8-quinolinolato)zinc(II) (abbreviation: Znq), and metal complexes having an oxazole ring or a thiazole ring, such as bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO) and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ).

[0041] Examples of organic compounds having electron transport properties include perylene derivatives and nitrogen-containing condensed aromatic compounds.

[0042] Specific examples of perylene derivatives include 3,4,9,10-perylenetetracarboxylic dianhydride (abbreviation: PTCDA), 3,4,9,10-perylenetetracarboxylic-bis-benzimidazole (abbreviation: PTCBI), N,N'-dioctyl-3,4,9,10-perylenetetracarboxylic diimide (abbreviation: PTCDI-CH), N,N'-dihexyl-3,4,9,10-perylenetetracarboxylic diimide (abbreviation: Hex-PTCDI), and N,N'-dimethyl-3,4,9,10-perylenetetracarboxylic diimide (abbreviation: Me-PTCDI).

[0043] Specific examples of the nitrogen-containing condensed aromatic compound include benzimidazole derivatives, quinoxaline derivatives, dibenzoquinoxaline derivatives, quinazoline derivatives, and phenanthroline derivatives.More specifically, organic compounds containing heteroaromatic rings with polyazole rings, such as 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI) and 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), and 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: Bphen), Organic compounds containing heteroaromatic rings with a pyridine ring, such as 2,2-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P), 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviation: 2mPCCzPDBq), and 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II). , 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl-9H-carbazol-9-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2CzPDBq-III), 7-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h] Examples include quinoxaline (abbreviation: 7mDBTPDBq-II), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 2-{4-[9,10-di(2-naphthyl)-2-anthryl]phenyl}-1-phenyl-1H-benzimidazole (abbreviation: ZADN), and 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq).

[0044] The thickness of the buffer layer 152 is preferably 0.1 nm to 5 nm, and more preferably 0.5 nm to 3 nm. By using the buffer layer 152 with such a thickness, the organic semiconductor layer 151 can be sufficiently protected and the organic semiconductor device 100 can be prevented from being subjected to high voltage during the manufacturing process of the organic semiconductor device 100.

[0045] The organic semiconductor device 100 may be provided with multiple buffer layers. The organic semiconductor device 100 shown in FIG. 1B has a buffer layer 152 formed by stacking a buffer layer 152-1 and a buffer layer 152-2. For example, an organometallic compound may be used for both the buffer layer 152-1 and the buffer layer 152-2. Alternatively, for example, Alq3 or Liq may be used for the buffer layer 152-1, and a phthalocyanine complex compound may be used for the buffer layer 152-2.

[0046] The buffer layer 152 may be a mixed layer formed by mixing two or more materials selected from the above-mentioned materials. When multiple buffer layers are stacked, some or all of them may be mixed layers.

[0047] In the organic semiconductor device 100, it is preferable to use a highly heat-resistant material for the organic semiconductor layer 151, and it is more preferable to use a highly heat-resistant material for the uppermost surface of the organic semiconductor layer 151. In addition to providing the buffer layer 152, by configuring the organic semiconductor layer 151 in this way, damage to the organic semiconductor layer 151 can be further suppressed, and the organic semiconductor device 100 can be more effectively prevented from becoming high voltage.

[0048] Examples of highly heat-resistant materials that can be used for the organic semiconductor layer 151 include the nitrogen-containing condensed aromatic compounds described above. However, organic compounds containing a heteroaromatic ring with a pyridine ring are more preferable, and mPPhen2P is even more preferable. Compared to NBphen, which is also an organic compound containing a heteroaromatic ring with a pyridine ring, mPPhen2P has higher heat resistance and is more effective in suppressing the increase in voltage of the organic semiconductor device 100. Therefore, mPPhen2P can be suitably used for the organic semiconductor layer 151.

[0049] 1(C), the organic semiconductor device 100 may have a layer 156 between the buffer layer 152 and the second electrode 102. A material with high carrier injection properties can be used for the layer 156. Such a configuration can further prevent the organic semiconductor device 100 from requiring high voltage. The layer 156 is provided after the organic semiconductor layer 151 and the buffer layer 152 are formed by photolithography in the manufacturing process of the organic semiconductor device 100. Therefore, the side surfaces (edges) of the layer 156 do not need to be substantially flush with the side surfaces (edges) of the organic semiconductor layer 151 and the buffer layer 152.

[0050] 2A, the organic semiconductor device of one embodiment of the present invention can have a structure such as a photoelectric conversion device such as a solar cell or a photosensor, which includes an organic semiconductor layer 151 including a first electrode 165, a second electrode 166, and a photoelectric conversion layer 167, and a buffer layer 152, which are provided over an insulating layer 160. Alternatively, as shown in FIG. 2B, the organic semiconductor device can have a structure such as an organic EL device, which includes an organic semiconductor layer 151 including a first electrode 165, a second electrode 166, and a light-emitting layer 168, and a buffer layer 152, which are provided over an insulating layer 160.

[0051] The structure of this embodiment can be used in appropriate combination with structures of other embodiments.

[0052] (Embodiment 2) In this embodiment, a method for processing a buffer layer and an organic semiconductor layer included in an organic semiconductor device according to one embodiment of the present invention will be described with reference to FIGS.

[0053] One method widely used to fabricate organic semiconductor films into a specified shape is vacuum deposition using a metal mask (mask deposition). However, with the recent trend toward higher density and higher definition, mask deposition is reaching its limit in terms of finer definition due to various reasons, including issues with alignment accuracy and the spacing between the substrate. On the other hand, by using photolithography to process the shape of organic semiconductor films, it is possible to form more precise patterns. Furthermore, because it is easy to fabricate large-area films, research into the processing of organic semiconductor films using photolithography is also progressing.

[0054] However, in order to process the shape of an organic semiconductor film using photolithography, many problems must be overcome, such as the effect of exposure of the organic semiconductor film to the atmosphere, the effect of light irradiation when exposing a photosensitive resin, the effect of the developer to which the exposed photosensitive resin is exposed when developing it, and the effect of forming a metal film when a metal film is formed to reduce the effect of the developer.

[0055] These effects are considered problematic because they can cause situations such as the organic semiconductor film itself disappearing or the surface of the organic semiconductor film being damaged, resulting in a significant deterioration in the characteristics of devices fabricated thereafter.

[0056] One way to solve the above-mentioned problems is to provide an aluminum oxide film 153a as a protective film on the organic semiconductor film 151a, as shown in Figure 3(A), and then perform the problematic process described above. The aluminum oxide film can be formed densely and has a high ability to block liquids and gases, making it possible to suppress the adverse effects of the process described above. Furthermore, the aluminum oxide film can be formed and removed using a method that causes minimal damage to the organic semiconductor film, making it extremely suitable as a protective film for the organic semiconductor film 151a.

[0057] As a method for forming the aluminum oxide film, atomic layer deposition (ALD) is preferred because it allows the formation of a denser film and causes less damage to the organic semiconductor film.

[0058] As described above, the aluminum oxide film is a film that inflicts relatively little damage on the organic semiconductor film during its formation and removal, and can be suitably used as a protective film when processing the organic semiconductor film by photolithography. However, if the surface of the organic semiconductor film is excessively exposed to the aluminum oxide film removal process, the surface 151s of the organic semiconductor film 151a may be damaged, as shown in FIG. 3(B), which may lead to deterioration of the organic semiconductor properties. Therefore, it is preferable to spend as little time as possible removing the aluminum oxide.

[0059] To minimize the removal process, the process can be terminated when all the aluminum oxide has been removed from the organic semiconductor film. However, determining when the aluminum oxide has been removed from the organic semiconductor film is extremely difficult. Furthermore, if the aluminum oxide film has in-plane variations in quality, the etching process (the aluminum oxide removal process) can result in in-plane variations in the etching rate. As shown in Figure 3(C), even if some portions of the aluminum oxide film are successfully removed, aluminum oxide film 153r may remain in other areas. In particular, when forming an aluminum oxide film on an organic film using the ALD method, the in-plane variations described above are likely to occur because high temperatures cannot be used for film formation. This can result in the partial formation of residual aluminum oxide film 153r. Residual aluminum oxide on the organic semiconductor film can increase the driving voltage of the device to be fabricated later. Furthermore, excessive etching to completely remove the residual aluminum oxide film 153r is highly undesirable because it can result in side etching of aluminum oxide that should be left in the process (aluminum oxide that is not removed) in the direction of adjacent pixels.

[0060] Therefore, in one embodiment of the present invention, a buffer film 152a is provided between the organic semiconductor film 151a and the aluminum oxide film 153a to facilitate removal of the aluminum oxide film.

[0061] First, an organic semiconductor film 151a is formed on an underlayer 150 (FIG. 4(A)). The underlayer 150 may be an insulating film or a conductive film depending on the device to be fabricated thereafter. The organic semiconductor film 151a may be formed by a dry method such as vapor deposition, or by a wet method such as spin coating.

[0062] Next, a buffer film 152a is formed on the organic semiconductor film 151a (FIG. 4(A)). The buffer film 152a may be made of the same material as that described in Embodiment 1 as being usable for the buffer layer 152. The buffer film 152a is preferably formed by vacuum deposition.

[0063] Subsequently, an aluminum oxide film 153a is formed on the buffer film 152a (FIG. 4(A)). The aluminum oxide film 153a is preferably formed by a method that causes minimal damage to the organic semiconductor film 151a, and is preferably formed by the ALD method.

[0064] It is preferable to form a metal film or metal compound film 154a on the aluminum oxide film 153a (FIG. 4(B)). The presence of the buffer film 152a and the aluminum oxide film 153a can suppress damage to the organic semiconductor film 151a, so a film formation method that causes relatively large damage to the surface on which the metal film or metal compound film 154a is formed, such as sputtering. Examples of materials that can be used to form the metal film or metal compound film 154a include metals or metal compounds such as silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, alloys containing molybdenum and niobium, and alloys containing molybdenum and tungsten, as well as metal oxides such as indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO). Furthermore, indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide), etc. can also be used. Alternatively, indium tin oxide containing silicon can also be used.

[0065] Thereafter, a photosensitive resin is applied onto the metal film or metal compound film 154a to form a resin film 155a (FIG. 4(C)). The photosensitive resin may be a positive resist or a negative resist.

[0066] Next, the resin is exposed to light in accordance with its photosensitivity and developed to form a photomask layer 155 (FIG. 4(D)). The metal or metal compound film 154a is etched using the photomask layer 155 to form the metal or metal compound layer 154 (FIG. 4(E)). The metal or metal compound film 154a may be etched by wet etching or dry etching. It is preferable to select and use etching conditions that provide a higher selectivity for the metal or metal compound film 154a than the aluminum oxide film 153a.

[0067] After the metal layer or metal compound layer 154 is formed, the photomask layer 155 is removed (FIG. 5(A)). By forming the metal film or metal compound film 154a, the aluminum oxide film 153a, and the buffer film 152a on the organic semiconductor film 151a, the organic semiconductor film 151a is not adversely affected, such as being lost or damaged, during the processes of forming and removing the photomask layer 155, and therefore an organic semiconductor device with excellent characteristics can be fabricated.

[0068] Thereafter, etching is performed using the metal layer or metal compound layer 154 as a mask to form the organic semiconductor layer 151, the buffer layer 152, and the aluminum oxide layer 153 (FIG. 5(B)). These etchings may be performed by wet etching or dry etching, but dry etching is preferred.

[0069] After processing of the organic semiconductor layer 151 is completed, the metal layer or metal compound layer 154 is removed (FIG. 5(C)). The metal layer or metal compound layer 154 may be removed by etching, which may be wet etching or dry etching, but dry etching is preferred. The etching is preferably performed under conditions that provide a higher selective ratio for the metal layer or metal compound layer 154 than the aluminum oxide layer 153.

[0070] Finally, the aluminum oxide layer 153 is removed (FIG. 5(D)). The aluminum oxide layer 153 can be removed by etching, which may be wet etching or dry etching, but is preferably wet etching using an alkaline solution or an acidic solution. The presence of the buffer layer 152 on the organic semiconductor layer 151 prevents the surface of the organic semiconductor layer 151 from being exposed to an alkaline solution or an acidic solution, thereby preventing deterioration of the characteristics.

[0071] If a material highly soluble in water is used for the buffer layer 152, after removing a certain amount of the aluminum oxide layer 153, the remaining aluminum oxide layer 153 may be removed by treating it with water or a liquid containing water as a solvent. The removal method involves immersing the layer in water or a liquid containing water as a solvent for a certain period of time, followed by rinsing with a shower of pure water. Water is preferred as the liquid used for removal, as it causes less damage to the organic semiconductor layer 151.

[0072] When removing the aluminum oxide layer 153, a part of the buffer layer 152 may be removed at the same time.

[0073] The organic semiconductor layer 151 processed by such a process suffers little damage from processing, and can therefore be made into an organic semiconductor device with good characteristics. Furthermore, the aluminum oxide film 153r can be prevented from remaining on the surface of the organic semiconductor layer 151, which can prevent the organic semiconductor device to be fabricated subsequently from requiring high voltage.

[0074] The structure of this embodiment can be used in appropriate combination with structures of other embodiments.

[0075] (Embodiment 3) [Example of manufacturing method] In this embodiment, an example of a method for manufacturing an organic semiconductor device according to one embodiment of the present invention will be described with reference to the drawings. Here, a light-emitting device 450 as shown in FIG. 6 will be described as an example. The light-emitting device 450 is a light-emitting device including an organic EL device in which the organic semiconductor layer in Embodiment 1 or 2 is an EL layer. That is, what will be referred to as an EL layer hereinafter corresponds to the above-described organic semiconductor layer. Note that by using an organic semiconductor layer including a photoelectric conversion layer instead of the EL layer of the organic EL device, the device can also be used as a photosensor. A photosensor and an organic EL device may be included simultaneously in the light-emitting device.

[0076] 6A shows a schematic top view of a light-emitting device 450. The light-emitting device 450 includes a plurality of blue organic EL devices 110B, a plurality of green organic EL devices 110G, and a plurality of red organic EL devices 110R. In FIG. 6A, the light-emitting regions of the respective organic EL devices are labeled with R, G, and B to easily distinguish between the respective organic EL devices.

[0077] The organic EL devices 110B, 110G, and 110R are arranged in a matrix. Fig. 6(A) shows a so-called stripe arrangement in which organic EL devices of the same color are arranged in one direction. Note that the arrangement of the organic EL devices is not limited to this, and other arrangements such as a delta arrangement or a zigzag arrangement may also be used, or a pentile arrangement may also be used.

[0078] Organic EL device 110B, organic EL device 110G, and organic EL device 110R are arranged in the X direction. Organic EL devices of the same color are arranged in the Y direction that intersects with the X direction.

[0079] Organic EL device 110B, organic EL device 110G, and organic EL device 110R are organic EL devices having the configurations described in the first and second embodiments.

[0080] FIG. 6(B) is a schematic cross-sectional view corresponding to the dashed-dotted line A1-A2 in FIG. 6(A), and FIG. 6(C) is a schematic cross-sectional view corresponding to the dashed-dotted line B1-B2.

[0081] 6(B) shows cross sections of organic EL devices 110B, 110G, and 110R. The organic EL device 110B has a first electrode 101B (pixel electrode), a first EL layer 120B, a buffer layer 152B, a second EL layer 121 (electron injection layer), and a second electrode 102 (common electrode). The organic EL device 110G has a first electrode 101G (pixel electrode), a first EL layer 120G, a buffer layer 152G, a second EL layer 121, and a second electrode 102. The organic EL device 110R has a first electrode 101R (pixel electrode), a first EL layer 120R, a buffer layer 152R, a second EL layer 121, and a second electrode 102. The second EL layer 121 and the second electrode 102 are provided in common to the organic EL device 110B, the organic EL device 110G, and the organic EL device 110R. The second EL layer 121 and the second electrode 102 can also be referred to as common layers. In the present embodiment, an example will be described in which the first electrode 101 is an anode and the second electrode 102 is a cathode.

[0082] The first EL layer 120B of the organic EL device 110B contains a light-emitting organic compound that emits light having an intensity in at least the blue wavelength range. The first EL layer 120G of the organic EL device 110G contains a light-emitting organic compound that emits light having an intensity in at least the green wavelength range. The first EL layer 120R of the organic EL device 110R contains a light-emitting organic compound that emits light having an intensity in at least the red wavelength range.

[0083] The first EL layer 120B, the first EL layer 120G, and the first EL layer 120R each have at least an emitting layer and may additionally have one or more of a hole blocking layer, an electron injection layer, an electron transport layer, a hole transport layer, a hole injection layer, an electron blocking layer, an exciton blocking layer, and the like. The second EL layer 121 does not have an emitting layer. The second EL layer 121 is preferably an electron injection layer. The first EL layer 120B, the first EL layer 120G, and the first EL layer 120R correspond to the organic semiconductor layer 151 in the organic semiconductor device 100 described in Embodiment 1. The second EL layer 121 corresponds to the layer 156 described in Embodiment 1. If the surfaces of the first EL layer 120B, the first EL layer 120G, and the first EL layer 120R on the second electrode side also function as an electron injection layer, the second EL layer 121 does not need to be provided.

[0084] The first electrode 101B, the first electrode 101G, and the first electrode 101R are provided for each organic EL device, respectively. The second electrode 102 and the second EL layer 121 are preferably provided as a continuous layer common to each organic EL device.

[0085] A conductive film that is translucent to visible light is used for either the first electrode 101 or the second electrode 102, and a conductive film that is reflective is used for the other. By making the first electrode 101 translucent and the second electrode 102 reflective, a bottom-emission display device can be obtained. Conversely, by making each first electrode 101 reflective and the second electrode 102 translucent, a top-emission display device can be obtained. Note that by making both each first electrode and the second electrode 102 translucent, a dual-emission display device can also be obtained. The organic EL device of this embodiment is suitable for a top-emission organic EL device.

[0086] A first EL layer 120B, a first EL layer 120G, and a first EL layer 120R are provided to cover the edges of the first electrode 101B, the first electrode 101G, and the first electrode 101R, respectively. A buffer layer 152B is provided on the first EL layer 120B. A buffer layer 152G is provided on the first EL layer 120G. A buffer layer 152R is provided on the first EL layer 120R. An insulating layer 125 is provided to cover the edges of the first EL layer 120B, the first EL layer 120G, the first EL layer 120R, the buffer layer 152B, the buffer layer 152G, and the buffer layer 152R. In other words, the insulating layer 125 has openings that overlap with the first electrode 101B, the first electrode 101G, and the first electrode 101R, the first EL layer 120B, the first EL layer 120G, the first EL layer 120R, the buffer layer 152B, the buffer layer 152G, and the buffer layer 152R. Edges of the openings in the insulating layer 125 are preferably tapered. Note that the edges of the first electrode 101B, the first electrode 101G, and the first electrode 101R do not necessarily have to be covered with the first EL layer 120B, the first EL layer 120G, and the first EL layer 120R, respectively.

[0087] The first EL layer 120B, the first EL layer 120G, and the first EL layer 120R have regions in contact with the upper surfaces of the first electrode 101B, the first electrode 101G, and the first electrode 101R, respectively. Ends of the first EL layer 120B, the first EL layer 120G, the first EL layer 120R, the buffer layer 152B, the buffer layer 152G, and the buffer layer 152R are located under the insulating layer 125. The upper surfaces of the buffer layer 152B on the first EL layer 120B, the buffer layer 152G on the first EL layer 120G, and the buffer layer 152R on the first EL layer 120R have regions in contact with the second EL layer 121 (or the second electrode 102 in the case where a second EL layer is not provided).

[0088] FIG. 7 is a modification of FIG. 6(B). In FIG. 7, the ends of the first electrode 101B, the first electrode 101G, and the first electrode 101R have a tapered shape that widens toward the substrate side, improving the coverage of a film formed thereon. The ends of the first electrode 101B, the first electrode 101G, and the first electrode 101R are covered with the first EL layer 120B, the first EL layer 120G, and the first EL layer 120R, respectively. A buffer layer 152B is formed covering the first EL layer 120B. A buffer layer 152G is formed covering the first EL layer 120G. A buffer layer 152R is formed covering the first EL layer 120R. This serves to prevent the EL layers from being damaged when etching is performed by photolithography. Furthermore, the edges of first EL layer 120B, first EL layer 120G, and first EL layer 120R are each covered with insulating layer 126. An insulating layer 108 is provided in a region between organic EL device 110B, organic EL device 110G, and organic EL device 110R and located on insulating layer 126. The edges of insulating layer 108 have a gently tapered shape, which can prevent discontinuity of second EL layer 121 and second electrode 102, which will be formed later.

[0089] As shown in FIGS. 6B and 7, a gap is provided between the two EL layers of organic EL devices of different colors. In this way, it is preferable that the first EL layer 120B, the first EL layer 120G, and the first EL layer 120R are arranged so as not to contact each other. This effectively prevents current from flowing through two adjacent EL layers, which would otherwise cause unintended light emission. This improves contrast and realizes a display device with high display quality. Furthermore, by using photolithography, the gap between the edges of the opposing EL layers of adjacent organic EL devices (e.g., organic EL device 110B and organic EL device 110G) can be set to 2 μm or more and 5 μm or less. This can also be interpreted as the gap between the light-emitting layers included in the EL layer. It is difficult to achieve a gap of less than 10 μm using a metal mask formation method.

[0090] In this way, by fabricating a light-emitting device using a photolithography method, the area of ​​a non-light-emitting region that may exist between two organic EL devices can be significantly reduced, and the aperture ratio can be significantly increased. For example, in a display device according to one embodiment of the present invention, the aperture ratio can be 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, or even 90% or more, but less than 100%.

[0091] Increasing the aperture ratio of a display device can improve the reliability of the display device. More specifically, when the lifespan of a display device using an organic EL device and having an aperture ratio of 10% is taken as the standard, the lifespan of a display device having an aperture ratio of 20% (i.e., an aperture ratio twice as high as the standard) is approximately 3.25 times longer, and the lifespan of a display device having an aperture ratio of 40% (i.e., an aperture ratio four times as high as the standard) is approximately 10.6 times longer. As such, as the aperture ratio increases, the current density flowing through the organic EL device can be reduced, thereby improving the lifespan of the display device. In the display device described in this embodiment, the aperture ratio can be increased, thereby improving the display quality of the display device. Furthermore, as the aperture ratio of the display device increases, an excellent effect is achieved, such as a significant improvement in the reliability (especially the lifespan) of the display device.

[0092] 6C shows an example in which the first EL layer 120R is formed so as to be separated for each organic EL device in the Y direction. While FIG. 6C shows a cross section of the organic EL device 110R as an example, the organic EL device 110G and the organic EL device 110B may also have a similar shape. The EL layer may be continuous in the Y direction, with the first EL layer 120R formed in a strip shape. Forming the first EL layer 120R and the like in a strip shape eliminates the need for a space to separate them, reducing the area of ​​the non-light-emitting region between the organic EL devices and increasing the aperture ratio.

[0093] A barrier layer 131 is provided on the second electrode 102 to cover the organic EL device 110B, the organic EL device 110G, and the organic EL device 110R. The barrier layer 131 has a function of preventing impurities that could adversely affect each organic EL device from diffusing from above.

[0094] The barrier layer 131 may have, for example, a single-layer structure or a multilayer structure including at least an inorganic insulating film. Examples of the inorganic insulating film include oxide films or nitride films such as a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, an aluminum oxide film, an aluminum oxynitride film, and a hafnium oxide film. Alternatively, the barrier layer 131 may be made of a semiconductor material such as indium gallium oxide or indium gallium zinc oxide.

[0095] Alternatively, the barrier layer 131 may be a laminated film of an inorganic insulating film and an organic insulating film. For example, a configuration in which an organic insulating film is sandwiched between a pair of inorganic insulating films is preferable. Furthermore, it is preferable that the organic insulating film functions as a planarizing film. This allows the upper surface of the organic insulating film to be flat, improving the coverage of the inorganic insulating film thereon and enhancing the barrier properties. Furthermore, since the upper surface of the barrier layer 131 is flat, when a structure (e.g., a color filter, a touch sensor electrode, or a lens array) is provided above the barrier layer 131, the influence of uneven shapes caused by the structure below can be reduced, which is preferable.

[0096] 6(A) also shows a connection electrode 101C that is electrically connected to the second electrode 102. The connection electrode 101C is given a potential (e.g., an anode potential or a cathode potential) to be supplied to the second electrode 102. The connection electrode 101C is provided outside the display area where the organic EL devices 110B and the like are arranged. In addition, in FIG. 6(A), the second electrode 102 is shown by a dashed line.

[0097] The connection electrode 101C can be provided along the periphery of the display area. For example, it may be provided along one side of the periphery of the display area, or it may be provided over two or more sides of the periphery of the display area. That is, when the top surface of the display area has a rectangular shape, the top surface of the connection electrode 101C can have a strip shape, an L-shape, a U-shape (square bracket shape), a square shape, or the like.

[0098] Fig. 6(D) is a schematic cross-sectional view corresponding to the dashed-dotted line C1-C2 in Fig. 6(A). Fig. 6(D) shows a connection portion 130 where the connection electrode 101C and the second electrode 102 are electrically connected. In the connection portion 130, the second electrode 102 is provided in contact with the connection electrode 101C, and a barrier layer 131 is provided covering the second electrode 102. In addition, an insulating layer 125 is provided covering the end of the connection electrode 101C.

[0099] 8(A) to 9(F) are schematic cross-sectional views illustrating the steps of the above-described method for manufacturing the light-emitting device 450. Also shown on the right side of each of these views are schematic cross-sectional views of the connection portion 130 and its vicinity.

[0100] The thin films (insulating films, semiconductor films, conductive films, etc.) that make up the display device can be formed using methods such as sputtering, chemical vapor deposition (CVD), vacuum evaporation, pulsed laser deposition (PLD), and atomic layer deposition (ALD). CVD methods include plasma enhanced chemical vapor deposition (PECVD) and thermal CVD. One type of thermal CVD method is metal organic chemical vapor deposition (MOCVD).

[0101] Furthermore, thin films (insulating films, semiconductor films, conductive films, etc.) that constitute the display device can be formed by methods such as spin coating, dipping, spray coating, inkjet, dispensing, screen printing, offset printing, doctor knife method, slit coating, roll coating, curtain coating, and knife coating.

[0102] Furthermore, when processing the thin films that constitute the display device, photolithography or the like can be used.

[0103] There are two typical photolithography methods: one is to form a resist mask on the thin film to be processed, process the thin film by etching or the like, and then remove the resist mask; the other is to form a photosensitive thin film, and then process the thin film into the desired shape by exposure and development.

[0104] In photolithography, the light used for exposure can be, for example, i-line (wavelength 365 nm), g-line (wavelength 436 nm), h-line (wavelength 405 nm), or a mixture of these. Other light sources that can be used include ultraviolet light, KrF laser light, and ArF laser light. Exposure can also be performed using immersion exposure technology. Light sources that can be used for exposure include extreme ultraviolet (EUV) light, X-rays, and the like. Electron beams can also be used instead of light for exposure. Extreme ultraviolet light, X-rays, or electron beams are preferred because they enable extremely fine processing. When exposure is performed by scanning a beam such as an electron beam, a photomask is not required.

[0105] For etching the thin film, dry etching, wet etching, sandblasting, or the like can be used.

[0106] [Preparation of the substrate 200] A substrate having heat resistance sufficient to withstand at least subsequent heat treatment can be used as the substrate 200. When an insulating substrate is used as the substrate 200, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, an organic resin substrate, or the like can be used. Also, a semiconductor substrate such as a single crystal semiconductor substrate made of silicon, silicon carbide, or the like, a polycrystalline semiconductor substrate, a compound semiconductor substrate such as silicon germanium, or an SOI substrate can be used.

[0107] In particular, it is preferable to use a substrate in which a semiconductor circuit including semiconductor elements such as transistors is formed on the semiconductor substrate or insulating substrate as the substrate 200. The semiconductor circuit preferably constitutes, for example, a pixel circuit, a gate line driving circuit (gate driver), a source line driving circuit (source driver), etc. In addition to the above, an arithmetic circuit, a memory circuit, etc. may also be constituted.

[0108] [Formation of First Electrodes 101B, 101G, 101R, and Connection Electrode 101C] Next, the first electrode 101B, the first electrode 101G, the first electrode 101R, and the connection electrode 101C are formed on the substrate 200. First, a conductive film to be the pixel electrode (first electrode) is formed, a resist mask is formed by photolithography, and unnecessary portions of the conductive film are removed by etching. After that, the resist mask is removed, whereby the first electrode 101B, the first electrode 101G, the first electrode 101R, and the connection electrode 101C can be formed (FIG. 8(A)).

[0109] When a conductive film reflective to visible light is used as each pixel electrode, it is preferable to use a material (such as silver or aluminum) with as high a reflectivity as possible across the entire wavelength range of visible light. This not only increases the light extraction efficiency of the organic EL device but also improves color reproducibility. When a conductive film reflective to visible light is used as each pixel electrode, a so-called top-emission light-emitting device can be achieved, in which light is extracted in the direction away from the substrate. When a light-transmitting conductive film is used as each pixel electrode, a so-called bottom-emission light-emitting device can be achieved, in which light is extracted toward the substrate.

[0110] [Formation of EL film 120Bb] Subsequently, an EL film 120Bb, which will later become the first EL layer 120B, is formed on the first electrode 101B, the first electrode 101G, and the first electrode 101R (FIG. 8(B)).

[0111] The EL film 120Bb has at least a light-emitting layer containing a light-emitting material. In addition, the EL film 120Bb may have a structure in which one or more films functioning as an electron injection layer, an electron transport layer, a charge generation layer, a hole transport layer, or a hole injection layer are stacked. The EL film 120Bb can be formed by, for example, a vapor deposition method, a sputtering method, an inkjet method, or the like. However, the method is not limited to these, and any known film formation method can be used as appropriate.

[0112] For example, the EL film 120Bb is preferably a laminated film in which a hole injection layer, a hole transport layer, a light-emitting layer, and an electron transport layer are laminated in this order. In this case, a film having an electron injection layer can be used as the second EL layer 121 to be formed later.

[0113] It is preferable that the EL film 120Bb is formed so as not to be provided on the connection electrode 101C. For example, when the EL film 120Bb is formed by vapor deposition (or sputtering), it is preferable that the EL film 120Bb is formed using a shielding mask so as not to be formed on the connection electrode 101C, or that the EL film 120Bb is removed in a subsequent etching step.

[0114] [Formation of buffer film 148a] Next, a buffer film 148a is formed to cover the EL film 120Bb. The buffer film 148a is preferably formed using a shielding mask so as not to be deposited on the connection electrode 101C, or it is preferably removed in a subsequent etching step.

[0115] The buffer film 148a is formed using the metals, organometallic compounds, organic compounds having electron transport properties, etc., as described in the first embodiment. Organometallic compounds are particularly suitable as materials for the buffer film 148a, which is formed to protect the EL film 120Bb and facilitate the removal of the aluminum oxide film to be formed later. Forming the buffer film 148a can prevent the organic EL device from operating at a high voltage. It can also suppress deterioration of the characteristics of the organic EL device.

[0116] [Formation of Aluminum Oxide Film 144a] Subsequently, an aluminum oxide film 144a is formed to cover the buffer film 148a and the connection electrode 101C. The aluminum oxide film 144a is preferably formed using a shielding mask so as not to be deposited on the connection electrode 101C, or is preferably removed in a subsequent etching step.

[0117] The aluminum oxide film 144a can be a film that is highly resistant to etching of each EL film, such as the EL film 120Bb, i.e., a film with a high etching selectivity. The aluminum oxide film 144a can also be a film that has a high etching selectivity with respect to a protective film, such as a metal film or metal compound film 146a (described later). Furthermore, the aluminum oxide film 144a can be a film that can be removed by wet etching, which causes minimal damage to each EL film.

[0118] The aluminum oxide film 144a can be formed by various film formation methods such as sputtering, vapor deposition, CVD, and ALD. However, it is preferable to use the ALD method, since it is possible to obtain a dense film with high barrier properties against atmospheric components such as oxygen or water and liquids such as water.

[0119] [Formation of Metal Film or Metal Compound Film 146a] Subsequently, a metal film or metal compound film 146a is formed on the aluminum oxide film 144a (FIG. 8(B)).

[0120] The metal film or metal compound film 146a is a film used as a hard mask when etching the aluminum oxide film 144a later. Furthermore, when processing the metal film or metal compound film 146a later, the aluminum oxide film 144a is exposed. Therefore, a combination of films with a high etching selectivity between the aluminum oxide film 144a and the metal film or metal compound film 146a is selected. Therefore, a film that can be used for the metal film or metal compound film 146a can be selected depending on the etching conditions for the aluminum oxide film 144a and the metal film or metal compound film 146a.

[0121] For example, when dry etching using a gas containing fluorine (also called a fluorine-based gas) is used to etch the metal film or metal compound film 146a, silicon, silicon nitride, silicon oxide, tungsten, titanium, molybdenum, tantalum, tantalum nitride, an alloy containing molybdenum and niobium, an alloy containing molybdenum and tungsten, etc. can be used for the metal film or metal compound film 146a. Here, examples of films that can achieve a large etching selectivity (i.e., a slower etching rate) compared to dry etching using the fluorine-based gas include metal oxide films.

[0122] Examples of metal oxides that can be used include indium gallium zinc oxide (In-Ga-Zn oxide, also referred to as IGZO). Other examples include indium oxide, indium zinc oxide (In-Zn oxide), indium tin oxide (In-Sn oxide), indium titanium oxide (In-Ti oxide), indium tin zinc oxide (In-Sn-Zn oxide), indium titanium zinc oxide (In-Ti-Zn oxide), and indium gallium tin zinc oxide (In-Ga-Sn-Zn oxide). Alternatively, silicon-containing indium tin oxide can be used.

[0123] It is also possible to use a metal oxide using an element M (wherein M is one or more elements selected from aluminum, silicon, boron, yttrium, copper, vanadium, beryllium, titanium, iron, nickel, germanium, zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum, tungsten, and magnesium) instead of the gallium. In particular, it is preferable that M is one or more elements selected from gallium, aluminum, and yttrium.

[0124] However, the metal film or metal compound film 146a is not limited to this, and can be selected from various materials depending on the etching conditions of the aluminum oxide film 144a and the etching conditions of the metal film or metal compound film 146a. For example, it can be selected from films that can be used for the aluminum oxide film 144a.

[0125] The metal film or metal compound film 146a may be, for example, a nitride film, such as silicon nitride, aluminum nitride, hafnium nitride, titanium nitride, tantalum nitride, tungsten nitride, gallium nitride, or germanium nitride.

[0126] Alternatively, an oxide film can be used as the metal film or metal compound film 146a. Typically, an oxide film or an oxynitride film such as silicon oxide, silicon oxynitride, aluminum oxynitride, hafnium oxide, or hafnium oxynitride can be used.

[0127] Alternatively, the metal film or metal compound film 146a may be an organic film that can be used for the EL film 120Bb, etc. Using such an organic film is preferable because it allows the film formation equipment to be shared with the EL film 120Bb, etc.

[0128] [Formation of resist mask 143a] Subsequently, resist masks 143a are formed on the metal film or metal compound film 146a at positions overlapping with the first electrode 101B and the connection electrode 101C (FIG. 8C).

[0129] The resist mask 143a can be made of a resist material containing a photosensitive resin, such as a positive resist material or a negative resist material.

[0130] If the resist mask 143a is formed on the aluminum oxide film 144a without the metal film or metal compound film 146a, defects such as pinholes in the aluminum oxide film 144a may cause the EL film 120Bb to dissolve in the solvent of the resist material. By using the metal film or metal compound film 146a, such defects can be prevented.

[0131] When a film that is less likely to cause defects such as pinholes is used for the aluminum oxide film 144a, the resist mask 143a may be formed directly on the aluminum oxide film 144a without using the metal film or metal compound film 146a.

[0132] [Etching of Metal Film or Metal Compound Film 146a] Subsequently, a portion of the metal or metal compound film 146a that is not covered by the resist mask 143a is removed by etching to form a strip-shaped or island-shaped metal or metal compound layer 147a. At this time, the metal or metal compound layer 147a is also formed on the connection electrode 101C.

[0133] When etching the metal film or metal compound film 146a, it is preferable to use etching conditions with a high selectivity so that the aluminum oxide film 144a is not removed by the etching. The metal film or metal compound film 146a can be etched by wet etching or dry etching, but using dry etching can prevent the pattern of the metal film or metal compound film 146a from shrinking.

[0134] [Removal of resist mask 143a] Subsequently, the resist mask 143a is removed (FIG. 8(D)).

[0135] The resist mask 143a can be removed by wet etching or dry etching. In particular, the resist mask 143a is preferably removed by dry etching (also called plasma ashing) using oxygen gas as an etching gas.

[0136] At this time, the resist mask 143a is removed while the EL film 120Bb is still covered with the aluminum oxide film 144a, so that the effect on the EL film 120Bb is suppressed. In particular, if the EL film 120Bb comes into contact with oxygen, it may have an adverse effect on the electrical characteristics, so this is suitable for etching using oxygen gas, such as plasma ashing.

[0137] [Etching of Aluminum Oxide Film 144a] Next, using the metal layer or metal compound layer 147a as a mask, a portion of the aluminum oxide film 144a that is not covered by the metal layer or metal compound layer 147a is removed by etching to form a strip-shaped aluminum oxide layer 145a (FIG. 8(E)). At the same time, the aluminum oxide layer 145a is also formed on the connection electrode 101C.

[0138] The aluminum oxide film 144a can be etched by wet etching or dry etching, but dry etching is preferable because it can prevent the pattern from shrinking.

[0139] [Etching of EL film 120Bb and metal layer or metal compound layer 147a] Subsequently, the metal layer or metal compound layer 147a is removed by etching, and at the same time, a part of the buffer film 148a not covered with the aluminum oxide layer 145a and a part of the EL film 120Bb are also removed by etching to form a strip-shaped buffer layer 152B and a first EL layer 120B (FIG. 8(F)). At this time, the metal layer or metal compound layer 147a on the connection electrode 101C is also removed.

[0140] Etching the buffer film 148a, the EL film 120Bb, and the metal layer or metal compound layer 147a in the same process is preferable because it simplifies the process and reduces the manufacturing cost of the display device.

[0141] In particular, dry etching using an etching gas that does not contain oxygen as a main component is preferable for etching the EL film 120Bb. This suppresses deterioration of the EL film 120Bb and realizes a highly reliable display device. Examples of etching gases that do not contain oxygen as a main component include noble gases such as CF4, C4F8, SF6, CHF3, Cl2, H2O, BCl3, H2, and He. Alternatively, a mixture of any of the above gases and a diluent gas that does not contain oxygen can be used as the etching gas.

[0142] The EL film 120Bb and the metal or metal compound layer 147a may be etched separately. In this case, the EL film 120Bb may be etched first, or the metal or metal compound layer 147a may be etched first.

[0143] At this point, the first EL layer 120B and the connection electrode 101C are covered with the aluminum oxide layer 145a.

[0144] [Formation of the first EL layer 120G and the first EL layer 120R] By repeating the same steps, an island-shaped first EL layer 120G, a buffer layer 152G, a first EL layer 120R, a buffer layer 152R, and island-shaped aluminum oxide layers 145b and 145c can be formed (FIG. 9(A)).

[0145] [Formation of insulating layer 126b] Subsequently, the insulating layer 126b is formed over the aluminum oxide layer 145a, the aluminum oxide layer 145b, and the aluminum oxide layer 145c (FIG. 9B). The insulating layer 126b can be formed in the same manner as the aluminum oxide layer 145a, the aluminum oxide layer 145b, and the aluminum oxide layer 145c.

[0146] [Formation of insulating layer 125b] After that, the insulating layer 125b is formed to cover the insulating layer 126b (FIG. 9C). The insulating layer 125b may be formed using a photosensitive organic resin. Examples of the organic material include acrylic resin, polyimide resin, epoxy resin, imide resin, polyamide resin, polyimideamide resin, silicone resin, siloxane resin, benzocyclobutene resin, phenol resin, and precursors of these resins. The insulating layer 125b may be formed using an organic material such as polyvinyl alcohol (PVA), polyvinyl butyral, polyvinylpyrrolidone, polyethylene glycol, polyglycerin, pullulan, water-soluble cellulose, or alcohol-soluble polyamide resin. The photosensitive resin may be a photoresist. The photosensitive resin may be a positive-type material or a negative-type material.

[0147] The insulating layer 125b is preferably subjected to heat treatment after application. The heat treatment is performed at a temperature lower than the heat resistance temperature of the EL layer. The substrate temperature during the heat treatment may be 50°C or higher and 200°C or lower, preferably 60°C or higher and 150°C or lower, and more preferably 70°C or higher and 120°C or lower. This allows the solvent contained in the insulating layer 125b to be removed.

[0148] Next, exposure and development are performed to form openings in the insulating layer 125b in areas that overlap with the first electrodes 101B, 101G, and 101R and the first EL layers 120B, 120G, and 120R, thereby forming the insulating layer 125 (FIG. 9(D)). When a positive acrylic resin is used for the insulating layer 125b, visible light or ultraviolet light may be irradiated using a mask onto the areas where the insulating layer 125b is to be removed.

[0149] When visible light is used for exposure, it is preferable that the visible light includes i-line (wavelength 365 nm). Visible light including g-line (wavelength 436 nm) or h-line (wavelength 405 nm) may also be used.

[0150] When an acrylic resin is used for the insulating layer 125b, it is preferable to use an alkaline solution as a developer, such as an aqueous solution of tetramethylammonium hydroxide (TMAH).

[0151] After that, it is preferable to expose the entire substrate to visible light or ultraviolet light to irradiate the insulating layer 125. The energy density of the exposure is 0 mJ / cm 2 Larger, 800mJ / cm 2 It is sufficient to set it to 0 mJ / cm 2 Larger, 500mJ / cm 2 The following is preferable. By performing such exposure after development, the transparency of the insulating layer 125 can be improved in some cases. Furthermore, the substrate temperature required for heat treatment in a later step for transforming the end portions of the insulating layer 125 into a tapered shape can be reduced in some cases.

[0152] Next, heat treatment is performed to transform the insulating layer 125b into an insulating layer 125 having tapered side surfaces. The heat treatment is performed at a temperature lower than the heat resistance temperature of the EL layer. The substrate temperature during the heat treatment is 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 130°C. The substrate temperature during the heat treatment in this step is preferably higher than that during the heat treatment performed after the application of the insulating layer 125. This can also improve the corrosion resistance of the insulating layer 125.

[0153] Next, a portion of insulating layer 126b exposed by forming an opening in insulating layer 125b is removed by wet etching, and at the same time, portions of aluminum oxide layer 145a, aluminum oxide layer 145b, and aluminum oxide layer 145c that are not covered by insulating layer 125b are removed by wet etching (Figure 9(E)).

[0154] For example, it is preferable to use wet etching using a tetramethylammonium hydroxide solution (TMAH), diluted hydrofluoric acid, oxalic acid, phosphoric acid, acetic acid, nitric acid, or a mixture of these.

[0155] When buffer layers 152B, 152G, and 152R are made of materials that are highly soluble in water, insulating layer 126b, aluminum oxide layer 145a, aluminum oxide layer 145b, and aluminum oxide layer 145c may be oxidized and removed to some extent by wet etching, and then the remaining insulating layer 126b, aluminum oxide layer 145a, aluminum oxide layer 145b, and aluminum oxide layer 145c may be removed by treating with water or a liquid containing water as a solvent. Because it is not necessary to completely remove aluminum oxide layer 145a, aluminum oxide layer 145b, and aluminum oxide layer 145c by wet etching, the EL layer is hardly damaged in the process of removing aluminum oxide layer 145a, aluminum oxide layer 145b, and aluminum oxide layer 145c.

[0156] Alternatively, it is preferable to remove parts of the insulating layer 126b, the aluminum oxide layer 145a, the aluminum oxide layer 145b, and the aluminum oxide layer 145c by dissolving them in a solvent such as water or alcohol. Here, various alcohols such as ethyl alcohol, methyl alcohol, isopropyl alcohol (IPA), and glycerin can be used as the alcohol capable of dissolving the aluminum oxide layer 145a, the aluminum oxide layer 145b, and the aluminum oxide layer 145c.

[0157] When removing parts of insulating layer 126b, aluminum oxide layer 145a, aluminum oxide layer 145b, and aluminum oxide layer 145c, parts of buffer layer 152B, buffer layer 152G, and buffer layer 152R may be removed at the same time.

[0158] Furthermore, parts of the insulating layer 126b, the aluminum oxide layer 145a, the aluminum oxide layer 145b, and the aluminum oxide layer 145c that are covered with the insulating layer 125 may remain as the insulating layer 126 and the aluminum oxide layer 145 without being removed by etching.

[0159] Furthermore, after removing portions of the insulating layer 126b, the aluminum oxide layer 145a, the aluminum oxide layer 145b, and the aluminum oxide layer 145c, it is preferable to perform drying treatment to remove water contained inside and adsorbed on the surfaces of the buffer layer 152B, the buffer layer 152G, the buffer layer 152R, the first EL layer 120B, the first EL layer 120G, and the first EL layer 120R. For example, it is preferable to perform heat treatment in an inert gas atmosphere or a reduced-pressure atmosphere. The heat treatment can be performed at a substrate temperature of 50°C to 200°C, preferably 60°C to 150°C, and more preferably 70°C to 120°C. A reduced-pressure atmosphere is preferable because it enables drying at a lower temperature.

[0160] In this manner, the first EL layer 120B, the first EL layer 120G, and the first EL layer 120R can be separately produced.

[0161] [Formation of the second EL layer 121] Subsequently, the second EL layer 121 is formed to cover the buffer layer 152B, the buffer layer 152G, the buffer layer 152R, and the insulating layer 125.

[0162] The second EL layer 121 can be formed by the same method as the EL film 120Bb, etc. When the second EL layer 121 is formed by evaporation, it is preferable to use a shielding mask so that the second EL layer 121 is not formed on the connection electrode 101C.

[0163] [Formation of the second electrode 102] Subsequently, the second electrode 102 is formed to cover the second EL layer 121 and the connection electrode 101C (FIG. 9(F)).

[0164] The second electrode 102 can be formed by a film formation method such as evaporation or sputtering. Alternatively, a film formed by evaporation and a film formed by sputtering may be stacked. In this case, the second electrode 102 is preferably formed so as to encompass a region where the electron-injection layer 115 is to be formed. That is, the second electrode 102 can have an edge portion overlapping with the second electrode 102. The second electrode 102 is preferably formed using a shielding mask.

[0165] The second electrode 102 is electrically connected to the connection electrode 101C outside the display area.

[0166] [Formation of Barrier Layer] Next, a barrier layer is formed on the second electrode 102. The inorganic insulating film used as the protective layer is preferably formed by sputtering, PECVD, or ALD. The ALD method is particularly preferred because it has excellent step coverage and is less likely to cause defects such as pinholes. The organic insulating film is preferably formed by inkjet printing, which allows for the formation of a uniform film in a desired area.

[0167] In this manner, a light-emitting device can be manufactured.

[0168] In the above description, the second electrode 102 and the second EL layer 121 are formed to have different top surface shapes; however, they may be formed in the same region.

[0169] The structure of this embodiment can be used in appropriate combination with structures of other embodiments.

[0170] (Fourth embodiment) In this embodiment, the configuration of an organic EL device, which is an organic semiconductor device having an EL layer as an organic semiconductor layer, will be described with reference to Fig. 10. The organic EL device is an organic semiconductor device including a configuration including an EL layer having a light-emitting layer between a first electrode 101 and a second electrode 102.

[0171] 10 shows a structure in which the buffer layer 152 is located between the electron-transport layer 114 and the electron-injection layer 115; however, the present invention is not limited thereto, and the buffer layer 152 may be located, for example, between the electron-injection layer 115 and the second electrode 102. The buffer layer 152 may have the structure described in Embodiment 1.

[0172] One of the first electrode 101 and the second electrode 102 functions as an anode, and the other functions as a cathode. Figure 10 explains an example in which the first electrode 101 is the anode.

[0173] The anode is preferably formed using a metal, alloy, conductive compound, or mixture thereof with a large work function (specifically, 4.0 eV or higher). Specific examples include indium tin oxide (ITO), indium tin oxide containing silicon or silicon oxide, indium zinc oxide, and indium oxide containing tungsten oxide and zinc oxide (IWZO). These conductive metal oxide films are usually formed by sputtering, but they may also be prepared by applying a sol-gel method. For example, indium zinc oxide may be formed by sputtering using a target containing indium oxide and 1 to 20 wt% zinc oxide. Indium oxide containing tungsten oxide and zinc oxide (IWZO) can also be formed by sputtering using a target containing indium oxide and 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide. Other examples of materials that can be used for the anode include gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), and nitrides of metal materials (e.g., titanium nitride). Graphene can also be used for the anode. By using a composite material (described later) in the layer of the EL layer 103 that contacts the anode, it becomes possible to select an electrode material regardless of the work function.

[0174] The EL layer 103 preferably has a stacked layer structure, but the stacked layer structure is not particularly limited, and various layer structures such as a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, an electron injection layer, a carrier blocking layer (hole blocking layer, electron blocking layer), an exciton blocking layer, and a charge generation layer can be applied. Note that any of the layers may not be provided. In this embodiment, a structure including 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 as shown in FIG. 10 will be specifically described below.

[0175] The hole-injection layer 111 is a layer containing a substance having acceptor properties. As the substance having acceptor properties, either an organic compound or an inorganic compound can be used.

[0176] As the acceptor substance, a compound having an electron-withdrawing group (a halogen group or a cyano group) can be used, and examples thereof include 7,7,8,8-tetracyano-2,3,5,6-tetrafluoroquinodimethane (abbreviation: F4-TCNQ), chloranil, 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (abbreviation: HAT-CN), 1,3,4,5,7,8-hexafluorotetracyano-naphthoquinodimethane (abbreviation: F6-TCNNQ), and 2-(7-dicyanomethylene-1,3,4,5,6,8,9,10-octafluoro-7H-pyren-2-ylidene)malononitrile. In particular, compounds in which an electron-withdrawing group is bonded to a fused aromatic ring having multiple heteroatoms, such as HAT-CN, are preferred because of their thermal stability. Radialene derivatives having an electron-withdrawing group (especially a halogen group such as a fluoro group or a cyano group) are also preferred because of their extremely high electron-accepting properties. Specific examples include α,α',α''-1,2,3-cyclopropanetriylidenetris[4-cyano-2,3,5,6-tetrafluorobenzeneacetonitrile], α,α',α''-1,2,3-cyclopropanetriylidenetris[2,6-dichloro-3,5-difluoro-4-(trifluoromethyl)benzeneacetonitrile], and α,α',α''-1,2,3-cyclopropanetriylidenetris[2,3,4,5,6-pentafluorobenzeneacetonitrile]. In addition to the organic compounds described above, other materials having acceptor properties can be used, such as molybdenum oxide, vanadium oxide, ruthenium oxide, tungsten oxide, manganese oxide, etc. The hole injection layer 111 can also be formed using phthalocyanine complex compounds such as phthalocyanine (abbreviated as HPc) and copper phthalocyanine (abbreviated as CuPc), aromatic amine compounds such as 4,4'-bis[N-(4-diphenylaminophenyl)-N-phenylamino]biphenyl (abbreviated as DPAB) and N,N'-bis[4-bis(3-methylphenyl)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviated as DNTPD), or polymers such as poly(3,4-ethylenedioxythiophene) / poly(styrenesulfonic acid) (abbreviated as PEDOT / PSS).A substance having acceptor properties can extract electrons from an adjacent hole transport layer (or hole transport material) when an electric field is applied.

[0177] Among substances having acceptor properties, organic compounds having acceptor properties are easy to use because they can be easily vapor-deposited and formed into a film.

[0178] Furthermore, a composite material in which the above-mentioned acceptor substance is contained in a material having a hole-transporting property can also be used for the hole-injection layer 111. Note that by using a composite material in which the acceptor substance is contained in a material having a hole-transporting property, a material for forming an electrode can be selected regardless of the work function. In other words, not only a material with a high work function but also a material with a low work function can be used for the anode.

[0179] As a material having hole transport properties to be used in the composite material, various organic compounds such as aromatic amine compounds, carbazole derivatives, aromatic hydrocarbons, and polymer compounds (oligomers, dendrimers, polymers, etc.) can be used. Note that as a material having hole transport properties to be used in the composite material, -6 cm 2 A substance having a hole mobility of 1 / Vs or more is preferred. Specific examples of organic compounds that can be used as a material having a hole transport property in a composite material are listed below.

[0180] Examples of aromatic amine compounds that can be used in composite materials include 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)aminophenyl]-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: DNTPD), and 1,3,5-tris[N-(4-diphenylaminophenyl)-N-phenylamino]benzene (abbreviation: DPA3B). Specific examples of the carbazole derivative include 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, and Examples of suitable carbazoles include carbazole (abbreviation: PCzPCN1), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 1,3,5-tris[4-(N-carbazolyl)phenyl]benzene (abbreviation: TCPB), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), and 1,4-bis[4-(N-carbazolyl)phenyl]-2,3,5,6-tetraphenylbenzene.Examples of aromatic hydrocarbons include 2-tert-butyl-9,10-di(2-naphthyl)anthracene (abbreviation: t-BuDNA), 2-tert-butyl-9,10-di(1-naphthyl)anthracene, 9,10-bis(3,5-diphenylphenyl)anthracene (abbreviation: DPPA), 2-tert-butyl-9,10-bis(4-phenylphenyl)anthracene (abbreviation: t-BuDBA), 9,10-di(2-naphthyl)anthracene (abbreviation: DNA), 9,10-diphenylanthracene (abbreviation: DPAnth), 2-tert-butylanthracene (abbreviation: t-BuAnth), 9,10-bis(4-methyl-1-naphthyl)anthracene (abbreviation: DMNA), 2-tert- Examples of suitable anthracene include butyl-9,10-bis[2-(1-naphthyl)phenyl]anthracene, 9,10-bis[2-(1-naphthyl)phenyl]anthracene, 2,3,6,7-tetramethyl-9,10-di(1-naphthyl)anthracene, 2,3,6,7-tetramethyl-9,10-di(2-naphthyl)anthracene, 9,9'-bianthryl, 10,10'-diphenyl-9,9'-bianthryl, 10,10'-bis(2-phenylphenyl)-9,9'-bianthryl, 10,10'-bis[(2,3,4,5,6-pentaphenyl)phenyl]-9,9'-bianthryl, anthracene, tetracene, rubrene, perylene, and 2,5,8,11-tetra(tert-butyl)perylene. Pentacene and coronene may also be used. The aromatic hydrocarbon having a vinyl group may also have a vinyl skeleton. Examples of the aromatic hydrocarbon having a vinyl group include 4,4'-bis(2,2-diphenylvinyl)biphenyl (abbreviation: DPVBi) and 9,10-bis[4-(2,2-diphenylvinyl)phenyl]anthracene (abbreviation: DPVPA). Note that the organic compound of one embodiment of the present invention can also be used.

[0181] In addition, polymer compounds 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 also be used.

[0182] The hole-transporting material used in the composite material preferably has a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, or an anthracene skeleton. In particular, aromatic amines having a substituent containing a dibenzofuran ring or a dibenzothiophene ring, aromatic monoamines having a naphthalene ring, or aromatic monoamines in which a 9-fluorenyl group is bonded to the nitrogen of the amine via an arylene group may be used. Furthermore, it is preferable that these organic compounds have an N,N-bis(4-biphenyl)amino group, as this allows for the fabrication of organic EL devices with long life. Specific examples of such organic compounds include N-(4-biphenyl)-6,N-diphenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BnfABP), N,N-bis(4-biphenyl)-6-phenylbenzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf), 4,4'-bis(6-phenylbenzo[b]naphtho[1,2-d]furan-8-i N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-6-amine (abbreviation: BBABnf(6)), N,N-bis(4-biphenyl)benzo[b]naphtho[1,2-d]furan-8-amine (abbreviation: BBABnf(8)), N,N-bis(4-biphenyl)benzo[b]naphtho[2,3-d]furan Ran-4-amine (abbreviation: BBABnf(II)(4)), N,N-bis[4-(dibenzofuran-4-yl)phenyl]-4-amino-p-terphenyl (abbreviation: DBfBB1TP), N-[4-(dibenzothiophen-4-yl)phenyl]-N-phenyl-4-biphenylamine (abbreviation: ThBA1BP), 4-(2-naphthyl)-4',4''-diphenyltriphenylamine (abbreviation: : BBAβNB), 4-[4-(2-naphthyl)phenyl]-4',4''-diphenyltriphenylamine (abbreviation: BBAβNBi), 4,4'-diphenyl-4''-(6;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB), 4,4'-diphenyl-4''-(7;1'-binaphthyl-2-yl)triphenylamine (abbreviation: BBAαNβNB-03), 4,4'-Diphenyl-4''-(7-phenyl)naphthyl-2-yltriphenylamine (abbreviation: BBAPβNB-03), 4,4'-diphenyl-4''-(6;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B), 4,4'-diphenyl-4''-(7;2'-binaphthyl-2-yl)triphenylamine (abbreviation: BBA(βN2)B-03), 4,4'-diphenyl-4''-(4;2'-binaphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB), 4,4'-diphenyl-4''-(5;2'-binaphthyl-2-yl)triphenylamine naphthyl-1-yl)triphenylamine (abbreviation: BBAβNαNB-02), 4-(4-biphenylyl)-4'-(2-naphthyl)-4''-phenyltriphenylamine (abbreviation: TPBiAβNB), 4-(3-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: mTPBiAβNBi), 4-(4-biphenylyl)-4'-[4-(2-naphthyl)phenyl]-4''-phenyltriphenylamine (abbreviation: TPBiAβNBi), 4-phenyl-4'-(1-naphthyl)triphenylamine amine (abbreviation: αNBA1BP), 4,4'-bis(1-naphthyl)triphenylamine (abbreviation: αNBB1BP), 4,4'-diphenyl-4''-[4'-(carbazol-9-yl)biphenyl-4-yl]triphenylamine (abbreviation: YGTBi1BP), 4'-[4-(3-phenyl-9H-carbazol-9-yl)phenyl]tris(1,1'-biphenyl-4-yl)amine (abbreviation: YGTBi1BP-02), 4-[4'-(carbazol-9-yl)biphenyl-4-yl]-4'-(2-naphthyl)-4''-phenyltriphenylamine Nylamine (abbreviation: YGTBiβNB), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-[4-(1-naphthyl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBNBSF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: BBASF), N,N-bis(biphenyl-4-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: BBASF(4)), N-(1,1'-biphenyl-2-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi[9H-fluorene]-4-amine (abbreviation: oFBiSF), N-(4-biphenyl)-N-(9,9-dimethyl-9H-fluoren-2-yl)dibenzofuran-4-amine (abbreviation: FrBiF), N-[4-(1-naphthyl)phenyl]-N-[3-(6-phenyldibenzofuran-4-yl)phenyl]-1-naphthylamine (abbreviation: mPDBfBNBN), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-furan phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-[4-(9-phenylfluoren-9-yl)phenyl]triphenylamine (abbreviated as BPAFLBi), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 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 PCBBi1BP), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-dimethyl-9H-fluoren-2-amine (abbreviation: PCBASF), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluoren]-2-amine (abbreviation: PCBASF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-2-amine Examples of suitable amines include PCBBiF (abbreviation: PCBBiF), N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-4-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-3-amine, N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-2-amine, and N,N-bis(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobi-9H-fluoren-1-amine.

[0183] It is more preferable that the material having hole transport properties used in the composite material has a relatively deep HOMO (Highest Occupied Molecular Orbital) level of −5.7 eV or more and −5.4 eV or less. When the material having hole transport properties used in the composite material has a relatively deep HOMO level, injection of holes into the hole transport layer 112 becomes easy, and an organic EL device with a long lifetime can be easily obtained. Furthermore, when the material having hole transport properties used in the composite material has a relatively deep HOMO level, induction of holes is appropriately suppressed, and an organic EL device with a long lifetime can be obtained.

[0184] The refractive index of the layer can be reduced by further mixing an alkali metal or alkaline earth metal fluoride with the composite material (preferably with a fluorine atom ratio of 20% or more in the layer), which also allows a layer with a low refractive index to be formed inside the EL layer 103, thereby improving the external quantum efficiency of the organic EL device.

[0185] By forming the hole injection layer 111, the hole injection property becomes good, and an organic EL device with a low driving voltage can be obtained.

[0186] The hole transport layer 112 is formed by including a material having a hole transport property. -6 cm 2 It is preferable that the hole mobility is / Vs or more.

[0187] Examples of the material having hole transport properties include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'-spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: BPAFLP), 4-phenyl-3'-(9 -phenylfluoren-9-yl)triphenylamine (abbreviated as mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviated as PCBA1BP), 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 PCBANB), compounds with an aromatic amine skeleton such as 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF); 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP); 4,4'-di(N-carbazolyl)biphenyl; phenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), 9,9'-bis(biphenyl-4-yl)-3,3'-bi-9H-carbazole (abbreviation: BisBPCz), 9,9'-bis(1,1'-biphenyl-3-yl)-3,3'-bi-9H-carbazole (abbreviation: BismBPCz), 9-(1,1'-biphenyl-3-yl)-9'-(1,1'-biphenyl-4-yl)-9H,9'H-3,3'-Bicarbazole (abbreviation: mBPCCBP), 9-(2-naphthyl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: βNCCP), 9-(3-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCmBP), 9-(4-biphenyl)-9'-(2-naphthyl)-3,3'-bi-9H-carbazole (abbreviation: βNCCBP), 9,9'-di-2-naphthyl-3,3'-9H,9'H-bicarbazole (abbreviation: :BisβNCz), 9-(2-naphthyl)-9'-[1,1':4',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-3-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-5'-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':4',1"- terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, 9-(2-naphthyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-phenyl-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole (abbreviation: PCCzTp), 9,9'-bis(triphenylene-2 -yl)-3,3'-9H,9'H-bicarbazole, 9-(4-biphenyl)-9'-(triphenylen-2-yl)-3,3'-9H,9'H-bicarbazole, 9-(triphenylen-2-yl)-9'-[1,1':3',1"-terphenyl]-4-yl-3,3'-9H,9'H-bicarbazole, and other compounds having a carbazole skeleton; 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II); 2,Examples of suitable compounds include compounds having a thiophene skeleton, such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton, such as 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. Note that the substances listed as materials having hole transport properties used in the composite material of the hole injection layer 111 can also be suitably used as materials for forming the hole transport layer 112.

[0188] The light-emitting layer 113 preferably contains a light-emitting substance and a first organic compound. It may further contain a second organic compound. The light-emitting layer 113 may also contain other materials. It may also be a stack of two layers with different compositions. It is preferable that the first organic compound is an organic compound having an electron-transporting property, and the second organic compound is an organic compound having a hole-transporting property.

[0189] The light-emitting substance may be a fluorescent substance, a phosphorescent substance, or a substance that exhibits thermally activated delayed fluorescence (TADF).

[0190] Examples of materials that can be used as the fluorescent substance in the light-emitting layer 113 include the following: In addition, fluorescent substances other than these can also be used.

[0191] 5,6-bis[4-(10-phenyl-9-anthryl)phenyl]-2,2'-bipyridine (abbreviation: PAP2BPy), 5,6-bis[4'-(10-phenyl-9-anthryl)biphenyl-4-yl]-2,2'-bipyridine (abbreviation: PAPP2BPy), N,N'-diphenyl-N,N'-bis[4-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine (abbreviation: 1,6FLPAPrn), N,N'-bis(3-methylphenyl)-N,N'-bis[3-(9-phenyl-9H-fluoren-9-yl)phenyl]pyrene-1,6-diamine )phenyl]pyrene-1,6-diamine (abbreviation: 1,6mMemFLPAPrn), N,N'-bis[4-(9H-carbazol-9-yl)phenyl]-N,N'-diphenylstilbene-4,4'-diamine (abbreviation: YGA2S), 4-(9H-carbazol-9-yl)-4'-(10-phenyl-9-anthryl)triphenylamine (abbreviation: YGAPA), 4-(9H-carbazol-9-yl)-4'-(9,10-diphenyl-2-anthryl)triphenylamine (abbreviation: 2YGAPPA), N,9-diphenyl-N-[4-( 10-phenyl-9-anthryl)phenyl]-9H-carbazol-3-amine (abbreviation: PCAPA), perylene, 2,5,8,11-tetra-tert-butylperylene (abbreviation: TBP), 4-(10-phenyl-9-anthryl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBAPA), N,N''-(2-tert-butylanthracene-9,10-diyldi-4,1-phenylene)bis[N,N',N'-triphenyl-1,4-phenylenediamine] (abbreviation: DPABPA), N,9 -diphenyl-N-[4-(9,10-diphenyl-2-anthryl)phenyl]-9H-carbazol-3-amine (abbreviated as 2PCAPPA), N-[4-(9,10-diphenyl-2-anthryl)phenyl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviated as 2DPAPPA), N,N,N',N',N'',N'',N''',N'''-octaphenyldibenzo[g,p]chrysene-2,7,10,15-tetraamine (abbreviated as DBC1), Coumarin 30, N-(9,10-diphenyl-2-anthryl)-N,9-Diphenyl-9H-carbazol-3-amine (abbreviation: 2PCAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,9-diphenyl-9H-carbazol-3-amine (abbreviation: 2PCABPhA), N-(9,10-diphenyl-2-anthryl)-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPAPA), N-[9,10-bis(1,1'-biphenyl-2-yl)-2-anthryl]-N,N',N'-triphenyl-1,4-phenylenediamine (abbreviation: 2DPA BPhA), 9,10-bis(1,1'-biphenyl-2-yl)-N-[4-(9H-carbazol-9-yl)phenyl]-N-phenylanthracen-2-amine (abbreviation: 2YGABPhA), N,N,9-triphenylanthracen-9-amine (abbreviation: DPhAPhA), Coumarin 545T, N,N'-diphenylquinacridone (abbreviation: DPQd), rubrene, 5,12-bis(1,1'-biphenyl-4-yl)-6,11-diphenyltetracene (abbreviation: BPT), 2-(2-{2-[4-(dimethylamino)phenyl]ethenyl}-6 -methyl-4H-pyran-4-ylidene)propanedinitrile (abbreviation: DCM1), 2-{2-methyl-6-[2-(2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCM2), N,N,N',N'-tetrakis(4-methylphenyl)tetracene-5,11-diamine (abbreviation: p-mPhTD), 7,14-diphenyl-N,N,N',N'-tetrakis(4-methylphenyl)acenaphtho[1,2-a]fluoranthene-3,10-diamine amine (abbreviation: p-mPhAFD), 2-{2-isopropyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTI), 2-{2-tert-butyl-6-[2-(1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: DCJTB),6-Bis{2-[4-(dimethylamino)phenyl]ethenyl}-4H-pyran-4-ylidene)propanedinitrile (abbreviation: BisDCM), 2-{2,6-bis[2-(8-methoxy-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H-benzo[ij]quinolizin-9-yl)ethenyl]-4H-pyran-4-ylidene}propanedinitrile (abbreviation: BisDCJTM), N,N'-diphenyl-N,N'-(1,6-pyren-diyl)bis[(6-phenylbenzo[b ]naphtho[1,2-d]furan)-8-amine] (abbreviation: 1,6BnfAPrn-03), 3,10-bis[N-(9-phenyl-9H-carbazol-2-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10PCA2Nbf(IV)-02), 3,10-bis[N-(dibenzofuran-3-yl)-N-phenylamino]naphtho[2,3-b;6,7-b']bisbenzofuran (abbreviation: 3,10FrA2Nbf(IV)-02), etc. In particular, condensed aromatic diamine compounds, such as pyrenediamine compounds, such as 1,6FLPAPrn, 1,6mMemFLPAPrn, and 1,6BnfAPrn-03, are preferred because of their high hole-trapping properties, excellent luminous efficiency, and reliability.

[0192] When a phosphorescent material is used as the light-emitting material in the light-emitting layer 113, examples of materials that can be used include the following.

[0193] Organometallic iridium complexes having a pyrimidine skeleton, 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 bis[4,6-di(naphthalen-1-yl)pyrimidinato](dipivaloylmethanato)iridium(III) (abbreviation: [Ir(d1npm)2(dpm)]), ( Organometallic iridium complexes with a pyrazine skeleton, such as (acetylacetonato)bis(2,3,5-triphenylpyrazinato)iridium(III) (abbreviation: [Ir(tppr)2(acac)]), bis(2,3,5-triphenylpyrazinato)(dipivaloylmethanato)iridium(III) (abbreviation: [Ir(tppr)2(dpm)]), and (acetylacetonato)bis[2,3-bis(4-fluorophenyl)quinoxalinato]iridium(III) (abbreviation: [Ir(Fdpq)2(acac)]), and tris(1-phenylisoquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(piq)3]), bis(1-phenylisoquinolinato-N,C 2’) iridium(III) acetylacetonate (abbreviated as [Ir(piq)2(acac)]), (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[7-(1-methylethyl)-1-isoquinolinyl-κN]phenyl-κC]iridium(III), and (3,7-diethyl-4,6-nonanedionato-κO4,κO6)bis[2,4-dimethyl-6-[5-(1-methylethyl)-2-quinolinyl-κN]phenyl-κC]iridium(III). In addition to iridium complexes, platinum complexes such as 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(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)]) are also useful. These complexes have emission peaks in the wavelength range from 600 nm to 700 nm. Furthermore, organometallic iridium complexes with a pyrazine skeleton can emit red light with good chromaticity. Other known red phosphorescent materials can also be used.

[0194] organometallic iridium complexes having a 4H-triazole skeleton, such as tris{2-[5-(2-methylphenyl)-4-(2,6-dimethylphenyl)-4H-1,2,4-triazol-3-yl-κN2]phenyl-κC}iridium(III) (abbreviation: [Ir(mpptz-dmp)3]) and tris(5-methyl-3,4-diphenyl-4H-1,2,4-triazolato)iridium(III) (abbreviation: [Ir(Mptz)3]); Organometallic iridium complexes with a 1H-triazole skeleton, such as tris[3-methyl-1-(2-methylphenyl)-5-phenyl-1H-1,2,4-triazolato]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]), and fac-tris[1-(2,6-di (isopropylphenyl)-2-phenyl-1H-imidazole]iridium(III) (abbreviation: [Ir(iPrpmi)3]), tris[3-(2,6-dimethylphenyl)-7-methylimidazo[1,2-f]phenanthridinato]iridium(III) (abbreviation: [Ir(dmpimpt-Me)3]), tris(2-[1-{2,6-bis(1-methylethyl)phenyl}-1H-imidazol-2-yl-κN3]-4-cyano organometallic iridium complexes with an imidazole skeleton such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), organometallic complexes with a benzimidazolidene skeleton such as tris[(6-tert-butyl-3-phenyl-2H-imidazo[4,5-b]pyrazin-1-yl-κC2)phenyl-κC]iridium(III) (abbreviation: [Ir(cb)3]), and organometallic complexes with a benzimidazolidene skeleton such as bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) tetrakis(1-pyrazolyl)borate (abbreviation: FIr6), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ]iridium(III) picolinate (abbreviation: FIrpic), bis{2-[3',5'-bis(trifluoromethyl)phenyl]pyridinato-N,C 2’}iridium(III) picolinate (abbreviation: [Ir(CF3ppy)2(pic)]), bis[2-(4',6'-difluorophenyl)pyridinato-N,C 2’ ] Organometallic iridium complexes with phenylpyridine derivatives bearing electron-withdrawing groups as ligands, such as iridium(III) acetylacetonate (abbreviated as FIracac), are compounds that exhibit blue phosphorescence, with peak emission in the wavelength range from 440 nm to 520 nm.

[0195] Also, tris(4-methyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)3]), tris(4-t-butyl-6-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)3]), (acetylacetonato)bis(6-methyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(mppm)2(acac)]), (acetylacetonato)bis(6-tert-butyl-4-phenylpyrimidinato)iridium(III) (abbreviation: [Ir(tBuppm)2(acac)]), (acetylacetonato)bis[6-(2-norbornyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(nbppm)2(acac)]), (acetylacetonato)bis[5-methyl-6- Organometallic iridium complexes with a pyrimidine skeleton, such as (2-methylphenyl)-4-phenylpyrimidinato]iridium(III) (abbreviation: [Ir(mpmppm)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)]), and tris(2-phenylpyridinato-N,C 2’) Iridium(III) (abbreviation: [Ir(ppy)3]), bis(2-phenylpyridinato-N,C 2’ ) Iridium(III) acetylacetonate (abbreviation: [Ir(ppy)2(acac)]), bis(benzo[h]quinolinato)iridium(III) acetylacetonate (abbreviation: [Ir(bzq)2(acac)]), tris(benzo[h]quinolinato)iridium(III) (abbreviation: [Ir(bzq)3]), tris(2-phenylquinolinato-N,C 2’ ) Iridium(III) (abbreviation: [Ir(pq)3]), bis(2-phenylquinolinato-N,C 2’) Iridium(III) acetylacetonate (abbreviation: [Ir(pq)2(acac)]), [2-d3-methyl-8-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviation: Ir(5mppy-d3)2(mbfpypy-d3)), [2-(methyl-d3)-8-[4-(1-methylethyl-1-d)-2-pyridinyl-κN]benzo [furo[2,3-b]pyridin-7-yl-κC]bis[5-(methyl-d3)-2-[5-(methyl-d3)-2-pyridinyl-κN]phenyl-κC]iridium(III) (abbreviated as Ir(5mtpy-d6)2(mbfpypy-iPr-d4)), [2-d3-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(ppy)2(mbfpy py-d3)), [2-(4-d3-methyl-5-phenyl-2-pyridinyl-κN2)phenyl-κC]bis[2-(5-d3-methyl-2-pyridinyl-κN2)phenyl-κC]iridium(III) (abbreviated as [Ir(5mppy-d3)2(mdppy-d3)]), [2-methyl-(2-pyridinyl-κN)benzofuro[2,3-b]pyridine-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as [Ir(ppy Examples include organometallic iridium complexes with a pyridine skeleton, such as [2-(4-methyl-5-phenyl-2-pyridinyl-κN)phenyl-κC]bis[2-(2-pyridinyl-κN)phenyl-κC]iridium(III) (abbreviated as Ir(ppy)2(mdppy)), and rare earth metal complexes, such as tris(acetylacetonato)(monophenanthroline)terbium(III) (abbreviated as [Tb(acac)3(Phen)]). These compounds primarily exhibit green phosphorescence, with an emission peak in the wavelength range from 500 nm to 600 nm. Organometallic iridium complexes with a pyrimidine skeleton are particularly preferred due to their outstanding reliability and luminous efficiency.

[0196] TADF materials include fullerene and its derivatives, acridine and its derivatives, eosin derivatives, etc. Also available are metal-containing porphyrins containing magnesium (Mg), zinc (Zn), cadmium (Cd), tin (Sn), platinum (Pt), indium (In), or palladium (Pd). Examples of the metal-containing porphyrin include protoporphyrin-tin fluoride complex (SnF2(Proto IX)), mesoporphyrin-tin fluoride complex (SnF2(Meso IX)), hematoporphyrin-tin fluoride complex (SnF2(Hemato IX)), coproporphyrin tetramethyl ester-tin fluoride complex (SnF2(Copro III-4Me)), octaethylporphyrin-tin fluoride complex (SnF2(OEP)), etioporphyrin-tin fluoride complex (SnF2(Etio I)), and octaethylporphyrin-platinum chloride complex (PtCl2OEP), all of which are shown in the following structural formulas.

[0197] [ka]

[0198] In addition, 2-(biphenyl-4-yl)-4,6-bis(12-phenylindolo[2,3-a]carbazol-11-yl)-1,3,5-triazine (abbreviation: PIC-TRZ), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-9H,9'H-3,3'-bicarbazole (abbreviation: PCCzTzn), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviation: PCCzPTzn), and 2-[4-(10H-phenoxazin-10-yl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: PXZ), which are shown in the following structural formulas, are also available. Heterocyclic compounds having either or both of a π-electron rich heteroaromatic ring and a π-electron deficient heteroaromatic ring, such as 3-[4-(5-phenyl-5,10-dihydrophenazin-10-yl)phenyl]-4,5-diphenyl-1,2,4-triazole (abbreviation: PPZ-3TPT), 3-(9,9-dimethyl-9H-acridin-10-yl)-9H-xanthen-9-one (abbreviation: ACRXTN), bis[4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]sulfone (abbreviation: DMAC-DPS), and 10-phenyl-10H,10'H-spiro[acridin-9,9'-anthracene]-10'-one (abbreviation: ACRSA), can also be used. The heterocyclic compound has a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring, and therefore has high electron transport and hole transport properties, and is therefore preferred. Among the skeletons having a π-electron-deficient heteroaromatic ring, pyridine skeleton, diazine skeleton (pyrimidine skeleton, pyrazine skeleton, pyridazine skeleton), and triazine skeleton are preferred because they are stable and reliable. In particular, benzofuropyrimidine skeleton, benzothienopyrimidine skeleton, benzofuropyrazine skeleton, and benzothienopyrazine skeleton are preferred because they have high acceptor properties and good reliability. Furthermore, among the skeletons having a π-electron-rich heteroaromatic ring, acridine skeleton, phenoxazine skeleton, phenothiazine skeleton, furan skeleton, thiophene skeleton, and pyrrole skeleton are preferred because they are stable and reliable. Furthermore, a dibenzofuran skeleton is preferred as a furan skeleton, and a dibenzothiophene skeleton is preferred as a thiophene skeleton.Particularly preferred pyrrole skeletons include an indole skeleton, a carbazole skeleton, an indolocarbazole skeleton, a bicarbazole skeleton, and a 3-(9-phenyl-9H-carbazol-3-yl)-9H-carbazole skeleton. Substances in which a π-electron-rich heteroaromatic ring and a π-electron-deficient heteroaromatic ring are directly bonded are particularly preferred because the electron-donating property of the π-electron-rich heteroaromatic ring and the electron-accepting property of the π-electron-deficient heteroaromatic ring are both enhanced, thereby reducing the energy difference between the S1 level and the T1 level, thereby enabling efficient thermally activated delayed fluorescence. Instead of the π-electron-deficient heteroaromatic ring, an aromatic ring bonded to an electron-withdrawing group such as a cyano group may be used. Examples of π-electron-rich skeletons that can be used include aromatic amine skeletons and phenazine skeletons. Examples of usable π-electron-deficient skeletons include a xanthene skeleton, a thioxanthene dioxide skeleton, an oxadiazole skeleton, a triazole skeleton, an imidazole skeleton, an anthraquinone skeleton, a boron-containing skeleton such as phenylborane or boranthrene, an aromatic ring having a nitrile group or a cyano group such as benzonitrile or cyanobenzene, a heteroaromatic ring, a carbonyl skeleton such as benzophenone, a phosphine oxide skeleton, a sulfone skeleton, etc. In this way, a π-electron-deficient skeleton and a π-electron-rich skeleton can be used in place of at least one of a π-electron-deficient heteroaromatic ring and a π-electron-rich heteroaromatic ring.

[0199] [ka]

[0200] Alternatively, TADF materials may be used, which are capable of extremely fast and reversible intersystem crossing and emit light according to a thermal equilibrium model between singlet and triplet excited states. These TADF materials have an extremely short emission lifetime (excitation lifetime) for TADF materials, and can suppress efficiency decline in the high-brightness region of organic EL devices. Specific examples include materials with the molecular structure shown below.

[0201] [ka]

[0202] TADF materials are materials with a small difference between the S1 and T1 levels, and have the ability to convert triplet excitation energy to singlet excitation energy through reverse intersystem crossing. Therefore, triplet excitation energy can be upconverted to singlet excitation energy (reverse intersystem crossing) using a small amount of thermal energy, allowing for efficient generation of a singlet excited state. Triplet excitation energy can also be converted into light emission.

[0203] Furthermore, exciplexes (also known as exciplexes), which form an excited state with two types of substances, have an extremely small difference between the S1 and T1 levels and function as TADF materials that can convert triplet excitation energy into singlet excitation energy.

[0204] The phosphorescence spectrum observed at low temperatures (for example, 77 K to 10 K) can be used as an indicator of the T1 level. For a TADF material, when a tangent line is drawn at the base of the fluorescence spectrum on the short wavelength side and the energy of the wavelength of the extrapolated line is defined as the S1 level, and a tangent line is drawn at the base of the phosphorescence spectrum on the short wavelength side and the energy of the wavelength of the extrapolated line is defined as the T1 level, the difference between S1 and T1 is preferably 0.3 eV or less, and more preferably 0.2 eV or less.

[0205] When a TADF material is used as a light-emitting material, the S1 level of the host material is preferably higher than the S1 level of the TADF material, and the T1 level of the host material is preferably higher than the T1 level of the TADF material.

[0206] Examples of electron transport materials used in the host material include metal complexes such as 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: Znq), bis[2-(2-benzoxazolyl)phenolato]zinc(II) (abbreviation: ZnPBO), and bis[2-(2-benzothiazolyl)phenolato]zinc(II) (abbreviation: ZnBTZ), and organic compounds having a π-electron-deficient heteroaromatic ring. Examples of organic compounds having a π-electron-deficient heteroaromatic ring include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4 -oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl)phenyl]-9H-carbazole (abbreviation: CO11), 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1- Organic compounds containing heteroaromatic rings with polyazole skeletons such as phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), 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: 2mDB TBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 2,4-Bis[4-(1-naphthyl)phenyl]-6-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as 2,4NP-6PyPPm), 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2PPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviated as 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)phenyl]pyrimidine quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 11-[(3'-dibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviation: 11mDBtBPPnfpr), 11-[(3'-dibenzothiophen-4-yl)biphenyl-4-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine, 11-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]phenanthro[9',10':4 ,5]furo[2,3-b]pyrazine, 12-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenanthro[9',10':4,5]furo[2,3-b]pyrazine (abbreviated as 12PCCzPnfpr), 9-[(3'-9-phenyl-9H-carbazol-3-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9pmPCBPNfpr), 9-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 9PCCzNfpr), 10-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviated as 10PCCzNfpr), 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-(9,9-dimethylfluoren-2-yl)dibenzothiophen-4-yl]phenyl}naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mFDBtPNfpr), 9-[3'-(6-phenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfpr-02), 9-[3-(9'-phenyl-3,3'-bi-9H-carbazol-9-yl)phenyl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mPCCzPNfpr), 9-[3'-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2': Organic compounds containing heteroaromatic rings with a diazine skeleton, such as 4,5]furo[2,3-b]pyrazine and 11-[3'-(2,8-diphenyldibenzothiophen-4-yl)biphenyl-3-yl]phenanthro[9',10':4,5]furo[2,3-b]pyrazine; organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviated as 35DCzPPy) and 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviated as TmPyPB); organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 2-[3'-(9,9-dimethyl -9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1,3,5-triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine mBnfBPTzn-02), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-[3'-(triphenylen-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,Examples of suitable organic compounds include those containing heteroaromatic rings with a triazine skeleton, such as [5-triazin-2-yl]-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn) and 2-[1,1'-biphenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1''-terphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviation: mBP-TPDBfTzn). Among the above, organic compounds containing heteroaromatic rings with a diazine skeleton, organic compounds containing heteroaromatic rings with a pyridine skeleton, and organic compounds containing heteroaromatic rings with a triazine skeleton are preferred due to their high reliability. In particular, organic compounds containing heteroaromatic rings with a diazine (pyrimidine, pyrazine) skeleton and organic compounds containing heteroaromatic rings with a triazine skeleton have high electron transport properties and contribute to reduced driving voltage.

[0207] As the hole transport material used as the host material, an organic compound having an amine skeleton and a π-electron-rich heteroaromatic ring can be used. Examples of the organic compound having an amine skeleton and a π-electron-rich heteroaromatic ring include 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (abbreviation: NPB), N,N'-diphenyl-N,N'-bis(3-methylphenyl)-4,4'-diaminobiphenyl (abbreviation: TPD), N,N'-bis(9,9'spirobi[9H-fluoren]-2-yl)-N,N'-diphenyl-4,4'-diaminobiphenyl (abbreviation: BSPB), 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylbiphenyl (abbreviation: BSPB), and 4-phenyl-4'-(9-phenylfluoren-9-yl)triphenylbiphenyl (abbreviation: BSPB). 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4-phenyl-3'-(9-phenylfluoren-9-yl)triphenylamine (abbreviation: mBPAFLP), 4-phenyl-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBA1BP), 4,4'-diphenyl-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBBi1BP), 4-(1-naphthyl)-4'-(9-phenyl-9H-carbazol-3-yl)triphenylamine Aromatic compounds such as 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBANB), 4,4'-di(1-naphthyl)-4''-(9-phenyl-9H-carbazol-3-yl)triphenylamine (abbreviation: PCBNBB), 9,9-dimethyl-N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]fluoren-2-amine (abbreviation: PCBAF), and N-phenyl-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi[9H-fluorene]-2-amine (abbreviation: PCBASF) Compounds with aromatic amine skeletons, 1,3-bis(N-carbazolyl)benzene (abbreviation: mCP), 4,4'-di(N-carbazolyl)biphenyl (abbreviation: CBP), 3,6-bis(3,5-diphenylphenyl)-9-phenylcarbazole (abbreviation: CzTP), 3,3'-bis(9-phenyl-9H-carbazole) (abbreviation: PCCP), N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-bis(9,9-dimethyl-9H-fluoren-2-yl)amine (abbreviation: PCBFF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-(9,9-dimethyl-9H-fluoren-2-yl)-9,9-dimethyl-9H-fluoren-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren- N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9-diphenyl-9H-fluoren-4-amine, N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluoren)-2-amine (abbreviated as PCBBiSF), N-(1,1'-biphenyl-4-yl)-N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-9,9'-spirobi(9H-fluoren)-2-amine N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-2-amine compounds having a carbazole skeleton such as N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':3',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-4-amine, N-[4-(9-phenyl-9H-carbazol-3-yl)phenyl]-N-(1,1':4',1''-terphenyl-4-yl)-9,9-dimethyl-9H-fluoren-4-amine, 4,4',4''-(benzene-1,3,5-triyl)tri(dibenzothiophene) (abbreviation: DBT3P-II), 2,Examples of suitable compounds include compounds having a thiophene skeleton, such as 8-diphenyl-4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]dibenzothiophene (abbreviation: DBTFLP-III) and 4-[4-(9-phenyl-9H-fluoren-9-yl)phenyl]-6-phenyldibenzothiophene (abbreviation: DBTFLP-IV), and compounds having a furan skeleton, such as 4,4′,4″-(benzene-1,3,5-triyl)tri(dibenzofuran) (abbreviation: DBF3P-II) and 4-{3-[3-(9-phenyl-9H-fluoren-9-yl)phenyl]phenyl}dibenzofuran (abbreviation: mmDBFFLBi-II). Among the above, compounds having an aromatic amine skeleton and compounds having a carbazole skeleton are preferred because they have good reliability, high hole transport properties, and contribute to reducing driving voltage. In addition, the organic compounds listed as examples of materials having hole transport properties in the hole transport layer 112 can also be used as the hole transport material of the host.

[0208] By mixing an electron transport material and a hole transport material, the transport property of the light-emitting layer 113 can be easily adjusted, and the recombination region can be easily controlled. Also, a TADF material can be used as an electron transport material or a hole transport material.

[0209] The TADF materials that can be used as host materials are the same as those listed above. When a TADF material is used as a host material, the triplet excitation energy generated in the TADF material is converted to singlet excitation energy through reverse intersystem crossing, and the energy is then transferred to the light-emitting material, thereby increasing the luminous efficiency of the organic EL device. In this case, the TADF material functions as the energy donor, and the light-emitting material functions as the energy acceptor.

[0210] This is very effective when the luminescent material is a fluorescent luminescent material. In this case, in order to obtain high luminous efficiency, the S1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. In addition, the T1 level of the TADF material is preferably higher than the S1 level of the fluorescent luminescent material. Therefore, the T1 level of the TADF material is preferably higher than the T1 level of the fluorescent luminescent material.

[0211] It is also preferable to use a TADF material that emits light that overlaps with the wavelength of the lowest-energy absorption band of the fluorescent material, as this allows for smooth transfer of excitation energy from the TADF material to the fluorescent material, resulting in efficient light emission.

[0212] Furthermore, to efficiently generate singlet excitation energy from triplet excitation energy through reverse intersystem crossing, carrier recombination is preferred in the TADF material. It is also preferable that the triplet excitation energy generated in the TADF material does not transfer to triplet excitation energy in the fluorescent material. To achieve this, the fluorescent material preferably has a protecting group around the luminophore (the skeleton responsible for light emission) of the fluorescent material. The protecting group is preferably a substituent without a π bond, and is preferably a saturated hydrocarbon. Specific examples include alkyl groups with 3 to 10 carbon atoms, substituted or unsubstituted cycloalkyl groups with 3 to 10 carbon atoms, and trialkylsilyl groups with 3 to 10 carbon atoms. Multiple protecting groups are even more preferred. Substituents without a π bond have poor carrier transport properties, allowing for the distance between the TADF material and the luminophore of the fluorescent material to be increased without significantly affecting carrier transport and carrier recombination. Here, the term "luminophore" refers to the atomic group (skeleton) responsible for light emission in the fluorescent material. The luminophore preferably has a skeleton having a π bond, preferably contains an aromatic ring, and preferably has a fused aromatic ring or a fused heteroaromatic ring. Examples of the fused aromatic ring or the fused heteroaromatic ring include a phenanthrene skeleton, a stilbene skeleton, an acridone skeleton, a phenoxazine skeleton, and a phenothiazine skeleton. In particular, fluorescent substances having a naphthalene skeleton, an anthracene skeleton, a fluorene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a pyrene skeleton, a perylene skeleton, a coumarin skeleton, a quinacridone skeleton, or a naphthobisbenzofuran skeleton are preferred because of their high fluorescence quantum yield.

[0213] When a fluorescent emitting substance is used as the emitting substance, a material having an anthracene skeleton is suitable as the host material. Using a substance having an anthracene skeleton as the host material for a fluorescent emitting substance makes it possible to realize an emitting layer with both excellent luminous efficiency and durability. As a substance having an anthracene skeleton to be used as a host material, a diphenylanthracene skeleton, particularly a 9,10-diphenylanthracene skeleton, is preferred due to its chemical stability. Furthermore, host materials having a carbazole skeleton are preferred because of their enhanced hole injection and transport properties. However, host materials containing a benzocarbazole skeleton, in which a benzene ring is further condensed to carbazole, are even more preferred because their HOMO is approximately 0.1 eV shallower than that of carbazole, facilitating hole insertion. In particular, host materials containing a dibenzocarbazole skeleton are preferred because their HOMO is approximately 0.1 eV shallower than that of carbazole, facilitating hole insertion, and also exhibiting excellent hole transport properties and high heat resistance. Therefore, a more preferable host material is a substance having both a 9,10-diphenylanthracene skeleton and a carbazole skeleton (or a benzocarbazole skeleton or a dibenzocarbazole skeleton). Note that, from the viewpoint of the hole injection / transport property, a benzofluorene skeleton or a dibenzofluorene skeleton may be used instead of the carbazole skeleton.Examples of such substances include 9-phenyl-3-[4-(10-phenyl-9-anthryl)phenyl]-9H-carbazole (abbreviation: PCzPA), 3-[4-(1-naphthyl)-phenyl]-9-phenyl-9H-carbazole (abbreviation: PCPN), 9-[4-(10-phenyl-9-anthracenyl)phenyl]-9H-carbazole (abbreviation: CzPA), 7-[4-(10-phenyl-9-anthryl)phenyl]-7H-dibenzo[c,g]carbazole (abbreviation: cgDBCzPA), 6-[3-(9,10-diphenyl-2 -anthryl)phenyl]-benzo[b]naphtho[1,2-d]furan (abbreviation: 2mBnfPPA), 9-phenyl-10-{4-(9-phenyl-9H-fluoren-9-yl)biphenyl-4'-yl}anthracene (abbreviation: FLPPA), 9-(1-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: αN-βNPAnth), 9-(1-naphthyl)-10-(2-naphthyl)anthracene (abbreviation: α,β-ADN), 2-(10-phenylanthracen-9-yl)dibenzofuran, 2-(10-phenyl -9-anthracenyl)-benzo[b]naphtho[2,3-d]furan (abbreviation: Bnf(II)PhA), 9-(2-naphthyl)-10-[3-(2-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 1-[4-(10-[1,1'-biphenyl]-4-yl-9-anthracenyl)phenyl]-2-ethyl-1H-benzimidazole (abbreviation: EtBImPBPhA), 2,9-di(1-naphthyl)-10-phenylanthracene (abbreviation: 2αN-αNPhA), 9-(1-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: βN-mβNPAnth), 9-(2-naphthyl)-10-[3-(1-naphthyl)phenyl]anthracene (abbreviation: αN-mαNPAnth), 9-(1-naphthyl)-10-[4-(1-naphthyl)phenyl]anthracene (abbreviation: αN-αNPAnth), 9-(2-naphthyl)-10-[4-(2-naphthyl)phenyl]anthracene (abbreviation: βN-βNPAnth), 2-(1-naphthyl)-9-(2-naphthyl)-10-phenylanthracene (abbreviation: 2αN-βNPh), and the like.In particular, CzPA, cgDBCzPA, 2mBnfPPA, and PCzPA are preferable choices because they exhibit very good properties.

[0214] A phosphorescent material can be used as part of the mixed material. The phosphorescent material can be used as an energy donor that provides excitation energy to a fluorescent material when the fluorescent material is used as a light-emitting material.

[0215] The mixed materials may also form an exciplex. The exciplex is preferably selected from a combination that forms an exciplex that emits light that overlaps with the wavelength of the lowest-energy absorption band of the light-emitting material, because this allows for smooth energy transfer and efficient light emission. Furthermore, this configuration is also preferable because it reduces the driving voltage.

[0216] At least one of the materials forming the exciplex may be a phosphorescent material, which allows efficient conversion of triplet excitation energy into singlet excitation energy through reverse intersystem crossing.

[0217] A combination of materials that efficiently form an exciplex is preferably one in which the HOMO level of the hole-transporting material is equal to or higher than the HOMO level of the electron-transporting material. Furthermore, it is also preferable that the LUMO (Lowest Unoccupied Molecular Orbital) level of the hole-transporting material is equal to or higher than the LUMO level of the electron-transporting material. The LUMO and HOMO levels of the materials can be derived from the electrochemical properties (reduction potential and oxidation potential) of the materials measured by cyclic voltammetry (CV).

[0218] The formation of exciplexes can be confirmed by, for example, comparing the emission spectra of a hole-transporting material, an electron-transporting material, and a mixed film of these materials and observing the phenomenon that the emission spectrum of the mixed film is shifted to longer wavelengths than the emission spectra of each material (or has a new peak at longer wavelengths). Alternatively, it can be confirmed by comparing the transient photoluminescence (PL) of a hole-transporting material, the transient PL of an electron-transporting material, and a mixed film of these materials and observing differences in transient response, such as the transient PL lifetime of the mixed film having a longer-lived component or a larger proportion of delayed components than the transient PL lifetimes of the individual materials. The above-mentioned transient PL can also be interpreted as transient electroluminescence (EL). In other words, the formation of exciplexes can also be confirmed by comparing the transient EL of a hole-transporting material, the transient EL of an electron-transporting material, and a mixed film of these materials and observing differences in transient response.

[0219] When a hole-blocking layer is provided, the hole-blocking layer is in contact with the light-emitting layer 113 and contains an organic compound that has electron-transporting properties and can block holes. The organic compound constituting the hole-blocking layer is preferably a material that has excellent electron-transporting properties, poor hole-transporting properties, and a deep HOMO level. Specifically, the hole-blocking layer has a HOMO level that is 0.5 eV or more deeper than the HOMO level of the material contained in the light-emitting layer 113, and an electron mobility at a square root of an electric field strength [V / cm] of 600 is 1×10 -6 cm 2 A substance having an electron mobility of 1 / Vs or higher is preferred.

[0220] In particular, 2-{3-[3-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq), 2-{3-[2-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCzPDBq-02), 2-{3-[3-(N-phenyl-9H-carbazol-2-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline (abbreviated as 2mPCCz PDBq-03), 2-{3-[3-(N-(3,5-di-tert-butylphenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}dibenzo[f,h]quinoxaline, 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviated as mPCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviated as mPCCzPTzn-02 ), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviated as PCCzPTzn), 9-(4,6-diphenyl-1,3,5-triazin-2-yl)-9'-phenyl-3,3'-bi-9H-carbazole (abbreviated as PCCzTzn(CzT)), 9-[3-(4,6-diphenyl-pyrimidin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole (abbreviated as 2PCCzPPm), 9-(4,6-diphenyl-pyrimidin-2-yl)-9 '-Phenyl-3,3'-bi-9H-carbazole (abbreviation: 2PCCzPm), 4-[2-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]benzofuro[3,2-d]pyrimidine (abbreviation: 4PCCzBfpm-02), 4-{3-[3-(N-phenyl-9H-carbazole-3-yl)-9H-carbazole-9-yl]phenyl}benzo[h]quinazoline, and 9-[3-(2,6-diphenyl-pyridin-4-yl)phenyl]-9'-phenyl-3,3'-bi-9H-carbazole are preferred because they have good heat resistance.

[0221] When other materials are used for the hole blocking layer, an organic compound having a HOMO level deeper than the HOMO level of the material contained in the light-emitting layer 113 may be used from among materials that can be used for the hole transport layer described later.

[0222] The electron transport layer 114 is an organic compound having electron transport properties, and has an electron mobility of 1×10 when the square root of the electric field strength [V / cm] is 600. -6 cm 2 A substance having an electron mobility of 1 / Vs or more is preferred. Note that other substances can be used as long as they have a higher electron transporting property than holes. Note that the organic compound is preferably an organic compound having a π-electron-deficient heteroaromatic ring. The organic compound having a π-electron-deficient heteroaromatic ring is preferably one or more of, for example, an organic compound having a heteroaromatic ring with a polyazole skeleton, an organic compound having a heteroaromatic ring with a pyridine skeleton, an organic compound having a heteroaromatic ring with a diazine skeleton, and an organic compound having a heteroaromatic ring with a triazine skeleton.

[0223] Specific examples of organic compounds having a π-electron-deficient heteroaromatic ring that can be used in the electron transport layer include 2-(4-biphenylyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (abbreviation: PBD), 3-(4-biphenylyl)-4-phenyl-5-(4-tert-butylphenyl)-1,2,4-triazole (abbreviation: TAZ), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene (abbreviation: OXD-7), 9-[4-(5-phenyl-1,3,4-oxadiazol-2-yl]benzene] (abbreviation: OXD-8), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene] (abbreviation: OXD-9), 1,3-bis[5-(p-tert-butylphenyl)-1,3,4-oxadiazol-2-yl]benzene] (abbreviation: OXD-1 ... Organic compounds with an azole skeleton, such as 2,2',2''-(1,3,5-benzenetriyl)tris(1-phenyl-1H-benzimidazole) (abbreviation: TPBI), 2-[3-(dibenzothiophen-4-yl)phenyl]-1-phenyl-1H-benzimidazole (abbreviation: mDBTBIm-II), and 4,4'-bis(5-methylbenzoxazol-2-yl)stilbene (abbreviation: BzOs), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridinium, benzene (abbreviation: 35DCzPPy), 1,3,5-tri[3-(3-pyridyl)phenyl]benzene (abbreviation: TmPyPB), 3,5-bis[3-(9H-carbazol-9-yl)phenyl]pyridine (abbreviation: 35DCzPPy), bathophenanthroline (abbreviation: Bphen), bathocuproine (abbreviation: BCP), 2,9-di(naphthalen-2-yl)-4,7-diphenyl-1,10-phenanthroline (abbreviation: NBphen), 2,2'-(1,3-phenylene)bis(9-phenyl-1,10-phenanthroline) (abbreviation: mPPhen2P) Organic compounds containing heteroaromatic rings with a pyridine skeleton, such as 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4'-(9-phenyl-9H-carbazol-3-yl)-3,1'-biphenyl-1-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mpPCBPDBq), 2-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTPDBq-II), 2-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mDBTBPDBq-II), 2-[3'-(9H-carbazol-9-yl)biphenyl-3-yl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), 2-[4-(3,6-diphenyl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 2mCzBPDBq), phenyl-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), 6-[3-(dibenzothiophen-4-yl)phenyl]dibenzo[f,h]quinoxaline (abbreviation: 6mDBTPDBq-II), 9-[3'-(dibenzothiophen-4-yl)biphenyl-3-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9mDBtBPNfp r), 9-[(3'-dibenzothiophen-4-yl)biphenyl-4-yl]naphtho[1',2':4,5]furo[2,3-b]pyrazine (abbreviation: 9pmDBtBPNfpr), 4,6-bis[3-(phenanthrene-9-yl)phenyl]pyrimidine (abbreviation: 4,6mPnP2Pm), 4,6-bis[3-(4-dibenzothienyl)phenyl]pyrimidine (abbreviation: 4,6mDBTP2Pm-II), 4,6-bis[3-(9H-carbazol-9-yl)phenyl]pyrimidine (abbreviation: 4,6mCzP2Pm), 9,9'-[pyrimidine-4,6 -diylbis(biphenyl-3,3'-diyl)]bis(9H-carbazole) (abbreviation: 4,6mCzBP2Pm), 8-(1,1'-biphenyl-4-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8BP-4mDBtPBfpm), 3,8-bis[3-(dibenzothiophen-4-yl)phenyl]benzofuro[2,3-b]pyrazine (abbreviation: 3,8mDBtP2Bfpr), 4,8-bis[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mDBtP2Bfpm), 8-[3'-(dibenzothiophen-4-yl)(1,1'-biphenyl-3-yl)]naphtho[1',2':4,5]furo[3,2-d]pyrimidine (abbreviation: 8mDBtBPNfpm), 8-[(2,2'-binaphthalen)-6-yl]-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8(βN2)-4mDBtPBfpm), 2,2'-(pyridine-2,6-diyl)bis(4-phenylbenzo[h]quinazoline) (abbreviation 2,6(P-Bqn)2Py), 2,2'-(pyridine-2,6-diyl)bis{4-[4-(2-naphthyl)phenyl]-6-phenylpyrimidine} (abbreviated as 2,6(NP-PPm)2Py), 6-(1,1'-biphenyl-3-yl)-4-[3,5-bis(9H-carbazol-9-yl)phenyl]-2-phenylpyrimidine (abbreviated as 6mBP-4Cz2PPm), 2,4-bis[4-(1-naphthyl)phenyl]-6-[4-(3-pyridyl)phenyl]pyrimidine (abbreviated as 2,4NP-6PyPPm), 4-[3,5-bis(9H-carbazol-9-yl)phenyl]pyrimidine [4-(9-phenyl-9H-carbazol-9-yl)phenyl]-2-phenyl-6-(1,1'-biphenyl-4-yl)pyrimidine (abbreviation: 6BP-4Cz2PPm), 7-[4-(9-phenyl-9H-carbazol-2-yl)quinazolin-2-yl]-7H-dibenzo[c,g]carbazole (abbreviation: PC-cgDBCzQz), 8-(1,1':4',1"-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)phenyl]-[1]benzofuro[3,2-d]pyrimidine (abbreviation: 8mpTP-4mDBtPBfpm), 4,8-bis[3-(dibenz[ 4,8mCzP2Bfpm), 8-(1,1':4',1"-terphenyl-3-yl)-4-[3-(dibenzothiophen-4-yl)biphenyl-4-yl]-benzofuro[3,2-d]pyrimidine, 4,8-bis[3-(9H-carbazol-9-yl)phenyl]-benzofuro[3,2-d]pyrimidine (abbreviation: 4,8mCzP2Bfpm), 8-(1,1':4',1"-terphenyl-3-yl)-4-[3-(9-phenyl-9H-carbazol-3-yl)phenyl]-benzofuro[3,2-d]pyrimidine, 8-(1,1'-biphenyl-4-yl)-4-[3-(9-phenyl-9H-carbazol-3-yl)biphenyl-3-yl]-benzofuro[3,2-d]pyrimidine, 8-(1,1'-biphenyl-4-yl)-4-{3-[2-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}benzofuro[3,2-d]pyrimidine, 8-phenyl-4-{3-[2-(N-phenyl-9H-carbazol-3-yl)-9H-carbazol-9-yl]phenyl}benzofuro Organic compounds with a diazine skeleton such as [3,2-d]pyrimidine, 8-(1,1'-biphenyl-4-yl)-4-(3,5-di-9H-carbazol-9-yl-phenyl)benzofuro[3,2-d]pyrimidine, 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 2-[(1,1'-biphenyl)-4-yl]-4-phenyl-6-[9,9'-spirobi(9H-fluoren)-2-yl]-1,3,5 -triazine (abbreviation: BP-SFTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-8-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn), 2-{3-[3-(benzo[b]naphtho[1,2-d]furan-6-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mBnfBPTzn-02), 9-[4-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-3,3'-bi-9H-ca carbazole (abbreviation: PCCzPTzn), 9-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-9'-phenyl-2,3'-bi-9H-carbazole (abbreviation: mPCCzPTzn-02), 2-[3'-(9,9-dimethyl-9H-fluoren-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mFBPTzn), 5-[3-(4,6-diphenyl-1,3,5-triazin-2-yl)phenyl]-7,7-dimethyl-5H,7H-indeno[2,1-b]carbazole (abbreviation: mINc(II)PTzn), 2-{3-[3-(dibenzothiophen-4-yl)phenyl]phenyl}-4,6-diphenyl-1,3,5-triazine (abbreviation: mDBtBPTzn), 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine (abbreviation: TmPPPyTz), 2-[3-(2,6-dimethyl-3-pyridyl)-5-(9-phenanthryl)phenyl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mPn-mDMePyPTzn), 11-[4-(biphenyl-4-yl)-6-phenyl-1,3,5-triazin-2-yl]-11,12-dihydro-12-phenylin Examples of organic compounds having a triazine skeleton include dolo[2,3-a]carbazole (abbreviation: BP-Icz(II)Tzn), 2-[3'-(triphenylen-2-yl)-1,1'-biphenyl-3-yl]-4,6-diphenyl-1,3,5-triazine (abbreviation: mTpBPTzn), 3-[9-(4,6-diphenyl-1,3,5-triazin-2-yl)-2-dibenzofuranyl]-9-phenyl-9H-carbazole (abbreviation: PCDBfTzn), and 2-[1,1'-biphenyl]-3-yl-4-phenyl-6-(8-[1,1':4',1''-terphenyl]-4-yl-1-dibenzofuranyl)-1,3,5-triazine (abbreviation: mBP-TPDBfTzn). Among the above, organic compounds containing a heteroaromatic ring having a diazine skeleton, organic compounds containing a heteroaromatic ring having a pyridine skeleton, and organic compounds containing a heteroaromatic ring having a triazine skeleton are preferred because of their high reliability. In particular, organic compounds containing a heteroaromatic ring having a diazine (pyrimidine, pyrazine) skeleton and organic compounds containing a heteroaromatic ring having a triazine skeleton have high electron transport properties and contribute to reducing driving voltage.

[0224] The electron transport layer 114 having this structure may also serve as the electron injection layer 115.

[0225] Between the electron transport layer 114 and the second electrode (cathode) 102, it is preferable to provide a layer containing an alkali metal or alkaline earth metal, such as lithium fluoride (LiF), cesium fluoride (CsF), calcium fluoride (CaF), or 8-quinolinolato-lithium (abbreviated as Liq), or a compound or complex thereof, as the electron injection layer 115. A co-evaporated film of ytterbium (Yb) and lithium or a lithium compound is also preferable. The electron injection layer 115 may be an electride, which is a layer made of a substance having electron transport properties and which contains an alkali metal or alkaline earth metal or a compound thereof. Examples of electrides include a mixed oxide of calcium and aluminum to which electrons are highly added.

[0226] Note that a layer containing 50 wt % or more of the above alkali metal or alkaline earth metal fluoride in a substance having electron transport properties (preferably an organic compound having a bipyridine skeleton) can also be used as the electron-injection layer 115. Since this layer has a low refractive index, it is possible to provide an organic EL device with better external quantum efficiency.

[0227] Materials that can be used to form the cathode include metals, alloys, electrically conductive compounds, and mixtures thereof with a low work function (specifically, 3.8 eV or less). Specific examples of such cathode materials include alkali metals such as lithium (Li) and cesium (Cs), elements belonging to Group 1 or Group 2 of the periodic table such as magnesium (Mg), calcium (Ca), and strontium (Sr), alloys containing these (MgAg, AlLi), rare earth metals such as europium (Eu) and ytterbium (Yb), and alloys containing these. However, by providing an electron injection layer between the cathode and the electron transport layer, various conductive materials can be used as the cathode, regardless of the magnitude of the work function, such as Al, Ag, ITO, and indium oxide-tin oxide containing silicon or silicon oxide.

[0228] These conductive materials can be formed into films by dry methods such as vacuum deposition and sputtering, inkjet methods, spin coating, etc. Alternatively, they may be formed by a wet method using a sol-gel method, or by a wet method using a paste of a metal material.

[0229] In addition, various methods, whether dry or wet, can be used to form the EL layer 103. For example, vacuum deposition, gravure printing, offset printing, screen printing, inkjet printing, or spin coating may be used.

[0230] Furthermore, the above-mentioned electrodes or layers may be formed using different film formation methods.

[0231] The configuration of the layer provided between the anode and cathode is not limited to the above, but a configuration in which the light-emitting region where holes and electrons recombine is provided at a location away from the anode and cathode is preferred so as to suppress quenching caused by the proximity of the light-emitting region to the electrodes and the metal used in the carrier injection layer.

[0232] Furthermore, the hole transport layer and electron transport layer in contact with the light-emitting layer 113, particularly the carrier transport layer close to the recombination region in the light-emitting layer 113, are preferably made of a material having a band gap larger than the band gap of the light-emitting material constituting the light-emitting layer or the light-emitting material contained in the light-emitting layer, in order to suppress energy transfer from excitons generated in the light-emitting layer.

[0233] Note that the structure of this embodiment mode can be used in appropriate combination with structures of other embodiments.

[0234] (Embodiment 5) In this embodiment, a light-emitting device using an organic EL device manufactured by the manufacturing method of the organic EL device described in Embodiments 2 and 3 will be described with reference to FIGS. 11A and 11B. FIG. 11A is a top view showing the light-emitting device, and FIG. 11B is a cross-sectional view taken along dashed lines AB and CD shown in FIG. 11A. This light-emitting device includes a driver circuit section (source line driver circuit) 601, a pixel section 602, and a driver circuit section (gate line driver circuit) 603, all of which are shown by dotted lines, to control the light emission of the organic EL device. Also, 604 denotes a sealing substrate, 605 denotes a sealant, and the inside surrounded by the sealant 605 forms a space 607.

[0235] The routing wiring 608 is wiring for transmitting signals input to the source line driver circuit 601 and the gate line driver circuit 603, and receives video signals, clock signals, start signals, reset signals, etc. from an FPC (flexible printed circuit) 609, which serves as an external input terminal. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to this FPC. In this specification, the light-emitting device includes not only the light-emitting device itself, but also a state in which an FPC or PWB is attached to it.

[0236] Next, the cross-sectional structure will be described with reference to Fig. 11B. A driver circuit portion and a pixel portion are formed on an element substrate 610, and here, a source line driver circuit 601, which is the driver circuit portion, and one pixel in a pixel portion 602 are shown.

[0237] The element substrate 610 may be made of a substrate made of glass, quartz, organic resin, metal, alloy, semiconductor, or a plastic substrate made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, or the like.

[0238] The structure of the transistors used in the pixels and driver circuits is not particularly limited. For example, they may be inverted staggered transistors or staggered transistors. Furthermore, they may be top-gate or bottom-gate transistors. The semiconductor material used for the transistors is not particularly limited, and examples thereof include silicon, germanium, silicon carbide, and gallium nitride. Alternatively, an oxide semiconductor containing at least one of indium, gallium, and zinc, such as an In-Ga-Zn-based metal oxide, may be used.

[0239] The crystallinity of a semiconductor material used for a transistor is not particularly limited, and any of an amorphous semiconductor and a crystalline semiconductor (a microcrystalline semiconductor, a polycrystalline semiconductor, a single crystal semiconductor, or a semiconductor having a crystalline region in part) may be used. The use of a crystalline semiconductor is preferable because it can suppress deterioration of transistor characteristics.

[0240] Here, it is preferable to use an oxide semiconductor for semiconductor devices such as transistors provided in the pixels and driver circuits, as well as transistors used in touch sensors, which will be described later. In particular, it is preferable to use an oxide semiconductor having a wider band gap than silicon. By using an oxide semiconductor having a wider band gap than silicon, the current in the off state of the transistor can be reduced.

[0241] The oxide semiconductor preferably contains at least indium (In) or zinc (Zn), and more preferably contains an oxide represented by In-M-Zn oxide (M is a metal such as Al, Ti, Ga, Ge, Y, Zr, Sn, La, Ce, or Hf).

[0242] In particular, it is preferable to use, as the semiconductor layer, an oxide semiconductor film having a plurality of crystal parts whose c-axes are oriented perpendicular to the surface on which the semiconductor layer is formed or the top surface of the semiconductor layer and which does not have grain boundaries between adjacent crystal parts.

[0243] By using such a material for the semiconductor layer, fluctuations in electrical characteristics are suppressed, and a highly reliable transistor can be realized.

[0244] Furthermore, a transistor having the above-described semiconductor layer can retain charge stored in a capacitor through the transistor for a long period of time due to its low off-state current. By applying such a transistor to a pixel, it is possible to stop the driver circuit while maintaining the gray level of an image displayed in each display region. As a result, an electronic device with extremely low power consumption can be realized.

[0245] To stabilize the characteristics of the transistor, it is preferable to provide an underlayer film. The underlayer film can be formed as a single layer or a multilayer using an inorganic insulating film such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a silicon nitride oxide film. The underlayer film can be formed by a sputtering method, a CVD method (such as a plasma CVD method, a thermal CVD method, or an MOCVD method), an ALD method, a coating method, or a printing method. Note that the underlayer film need not be provided if it is not necessary.

[0246] Note that FET 623 represents one of the transistors formed in the source line driver circuit 601. The driver circuit may be formed of various CMOS circuits, PMOS circuits, or NMOS circuits. In addition, although this embodiment shows a driver-integrated type in which the driver circuit is formed on a substrate, this is not necessarily required, and the driver circuit may also be formed externally rather than on the substrate.

[0247] Furthermore, the pixel portion 602 is formed by a plurality of pixels each including a switching FET 611, a current control FET 612, and a first electrode 613 electrically connected to the drain of the FET, but is not limited to this, and the pixel portion may be formed by combining three or more FETs and a capacitive element.

[0248] An insulator 614 is formed to cover an end portion of the first electrode 613. Here, the insulator 614 can be formed using a positive photosensitive acrylic resin film.

[0249] Furthermore, in order to improve the coverage of an EL layer or the like to be formed later, a curved surface having a curvature is formed at the upper or lower end of the insulator 614. For example, when a positive photosensitive acrylic resin is used as the material for the insulator 614, it is preferable that only the upper end of the insulator 614 has a curved surface having a radius of curvature (0.2 μm to 3 μm). Furthermore, either a negative photosensitive resin or a positive photosensitive resin can be used as the insulator 614.

[0250] An EL layer 616 and a second electrode 617 are formed on the first electrode 613. Here, the first electrode 613 functions as an anode. Materials that can be used for the anode are preferably those with a large work function. For example, a single layer film such as an ITO film, an indium tin oxide film containing silicon, an indium oxide film containing 2 to 20 wt % zinc oxide, a titanium nitride film, a chromium film, a tungsten film, a Zn film, or a Pt film can be used. It is also possible to use a laminated structure with a film mainly composed of silver, a laminated structure with a titanium nitride film and a film mainly composed of aluminum, or a three-layer structure with a titanium nitride film, a film mainly composed of aluminum, and a titanium nitride film. The laminated structure provides low resistance as wiring, good ohmic contact, and the anode can function.

[0251] The EL layer 616 is formed by various methods such as a vapor deposition method using a vapor deposition mask, an inkjet method, a spin coating method, etc. The EL layer 616 includes the components described in the first and third embodiments.

[0252] Furthermore, the second electrode 617 formed on the EL layer 616 is preferably made of a material with a small work function (such as Al, Mg, Li, or Ca, or an alloy or compound thereof (MgAg, MgIn, AlLi, etc.)). When light generated in the EL layer 616 is transmitted through the second electrode 617, the second electrode 617 is preferably made of a stack of a thin metal or alloy film and a transparent conductive film (such as ITO, indium oxide containing 2 to 20 wt % zinc oxide, indium tin oxide containing silicon, or zinc oxide (ZnO)).

[0253] Note that an organic EL device is formed with the first electrode 613, the EL layer 616, and the second electrode 617. The organic EL device is an organic EL device manufactured by the manufacturing method of an organic EL device described in Embodiment 2 or 3. Note that a pixel portion is formed with a plurality of organic EL devices. However, the light-emitting device in this embodiment may include both organic EL devices manufactured by the manufacturing method of an organic EL device described in Embodiment 2 or 3 and organic EL devices having other structures. In this case, in the light-emitting device of one embodiment of the present invention, a common hole-transport layer can be used between the organic EL devices emitting light of different wavelengths, and therefore the light-emitting device can be manufactured with a simple manufacturing process and is cost-effective.

[0254] Furthermore, by bonding the sealing substrate 604 to the element substrate 610 with a sealant 605, an organic EL device 618 is provided in a space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. The space 607 is filled with a filler, which may be filled with an inert gas (nitrogen, argon, etc.) or a sealant. A recess is formed in the sealing substrate and a desiccant is provided therein, which is a preferable configuration because it can suppress deterioration due to the influence of moisture.

[0255] It is preferable to use epoxy resin or glass frit for the sealing material 605. It is also desirable that these materials are as moisture and oxygen impermeable as possible. In addition to glass substrates and quartz substrates, plastic substrates made of FRP (Fiber Reinforced Plastics), PVF (Polyvinyl Fluoride), polyester, acrylic resin, etc. can be used for the sealing substrate 604.

[0256] Although not shown in Figures 11(A) and 11(B), a protective film may be provided on the cathode. The protective film may be formed of an organic resin film or an inorganic insulating film. The protective film may also be formed so as to cover the exposed portion of the sealing material 605. The protective film may also be provided so as to cover the surfaces and side surfaces of the pair of substrates, the exposed side surfaces of the sealing layer, the insulating layer, etc.

[0257] The protective film can be made of a material that is impermeable to impurities such as water, and therefore can effectively prevent impurities such as water from diffusing from the outside to the inside.

[0258] The protective film may be made of an oxide, nitride, fluoride, sulfide, ternary compound, metal, polymer, or the like. For example, a material containing aluminum oxide, hafnium oxide, hafnium silicate, lanthanum oxide, silicon oxide, strontium titanate, tantalum oxide, titanium oxide, zinc oxide, niobium oxide, zirconium oxide, tin oxide, yttrium oxide, cerium oxide, scandium oxide, erbium oxide, vanadium oxide, indium oxide, or the like; a material containing aluminum nitride, hafnium nitride, silicon nitride, tantalum nitride, titanium nitride, niobium nitride, molybdenum nitride, zirconium nitride, or gallium nitride, or the like; a nitride containing titanium and aluminum, an oxide containing titanium and aluminum, an oxide containing aluminum and zinc, a sulfide containing manganese and zinc, a sulfide containing cerium and strontium, an oxide containing erbium and aluminum, or an oxide containing yttrium and zirconium, or the like.

[0259] The protective film is preferably formed using a film formation method that provides good step coverage. One such method is atomic layer deposition (ALD). It is preferable to use a material that can be formed using ALD for the protective film. By using ALD, it is possible to form a dense protective film with reduced defects such as cracks and pinholes, or with a uniform thickness. In addition, it is possible to reduce damage to the workpiece when forming the protective film.

[0260] For example, by forming a protective film using the ALD method, it is possible to form a uniform protective film with few defects on surfaces with complex uneven shapes, including the top, side, and back surfaces of a touch panel.

[0261] As described above, a light-emitting device manufactured using an organic EL device manufactured using the method for manufacturing an organic EL device described in Embodiments 2 and 3 can be obtained.

[0262] The light-emitting device in this embodiment uses an organic EL device manufactured using the method for manufacturing an organic EL device described in embodiments 2 and 3, and therefore, a light-emitting device with good characteristics can be obtained.

[0263] 12(A) and 12(B) show examples of light-emitting devices in which color purity is improved by providing a colored layer (color filter), etc. Fig. 12(A) shows a substrate 1001, a base insulating film 1002, a gate insulating film 1003, gate electrodes 1006, 1007, and 1008, a first interlayer insulating film 1020, a second interlayer insulating film 1021, a peripheral section 1042, a pixel section 1040, a driving circuit section 1041, first electrodes 1024R, 1024G, and 1024B of the organic EL device, a partition wall 1025, an EL layer 1028, a common electrode (cathode) 1029 of the organic EL device, a sealing substrate 1031, a sealing material 1032, etc.

[0264] 12(A), the colored layers (red colored layer 1034R, green colored layer 1034G, blue colored layer 1034B) are provided on a transparent base material 1033. A black matrix 1035 may also be provided. The transparent base material 1033 on which the colored layers and black matrix are provided is aligned and fixed to the substrate 1001. The colored layers and black matrix 1035 are covered with an overcoat layer 1036.

[0265] 12(B) shows an example in which colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B) are formed between the gate insulating film 1003 and the first interlayer insulating film 1020. In this way, the colored layers may be provided between the substrate 1001 and the sealing substrate 1031.

[0266] Furthermore, while the light-emitting device described above has a structure in which light is extracted from the substrate 1001 side on which the FET is formed (bottom emission type), it may also have a structure in which light is extracted from the sealing substrate 1031 side (top emission type). A cross-sectional view of a top emission type light-emitting device is shown in FIG. 13. In this case, a light-opaque substrate can be used as the substrate 1001. The process is the same as for a bottom emission type light-emitting device up to the fabrication of a connection electrode that connects the FET and the anode of the organic EL device. Thereafter, a third interlayer insulating film 1037 is formed to cover the electrode 1022. This insulating film may also serve as a planarizing film. The third interlayer insulating film 1037 can be formed using the same material as the second interlayer insulating film 1021, as well as other known materials.

[0267] The first electrodes 1024R, 1024G, and 1024B of the organic EL device are anodes in this example, but may be cathodes. In the case of a top-emission light-emitting device such as that shown in FIG. 13, it is preferable that the anodes be reflective electrodes. The EL layer 1028 has the same structure as that described for the EL layer 103 in the first embodiment.

[0268] In a top-emission structure such as that shown in FIG. 13, sealing can be performed using a sealing substrate 1031 provided with colored layers (a red colored layer 1034R, a green colored layer 1034G, and a blue colored layer 1034B). The sealing substrate 1031 may be provided with a black matrix 1035 positioned between pixels. The colored layers (the red colored layer 1034R, the green colored layer 1034G, and the blue colored layer 1034B) and the black matrix 1035 may be covered with an overcoat layer (not shown). Note that a light-transmitting substrate is used as the sealing substrate 1031.

[0269] A microcavity structure is suitable for use in top-emission light-emitting devices. An organic EL device with a microcavity structure can be obtained by using one electrode including a reflective electrode and the other electrode as a semi-transmissive / semi-reflective electrode. At least an EL layer is present between the reflective electrode and the semi-transmissive / semi-reflective electrode, and at least an emitting layer that becomes the light-emitting region is present.

[0270] The reflectance of the reflective electrode to visible light is 40% to 100%, preferably 70% to 100%, and the resistivity is 1×10 -2 The semi-transmitting and semi-reflective electrode has a visible light reflectance of 20% to 80%, preferably 40% to 70%, and a resistivity of 1×10 -2 It is assumed that the film has a resistance of Ωcm or less.

[0271] The light emitted from the light-emitting layer included in the EL layer is reflected by the reflective electrode and the semi-transmissive and semi-reflective electrode, causing resonance.

[0272] In this organic EL device, the optical distance between the reflective electrode and the semi-transmissive / semi-reflective electrode can be changed by changing the thickness of the transparent conductive film, the composite material described above, the carrier transport material, etc. This makes it possible to intensify light with resonant wavelengths and attenuate light with non-resonant wavelengths between the reflective electrode and the semi-transmissive / semi-reflective electrode.

[0273] Note that, since the light reflected by the reflective electrode and returned (first reflected light) significantly interferes with the light (first incident light) that directly enters the semi-transmissive-semi-reflective electrode from the light-emitting layer, it is preferable to adjust the optical distance between the reflective electrode and the light-emitting layer to (2n-1)λ / 4 (where n is a natural number greater than or equal to 1, and λ is the wavelength of the emitted light to be amplified). By adjusting this optical distance, the phases of the first reflected light and the first incident light can be matched, thereby further amplifying the light emitted from the light-emitting layer.

[0274] In the above configuration, the EL layer may have a structure having multiple light-emitting layers or a structure having a single light-emitting layer. For example, the EL layer may be combined with the above-mentioned tandem organic EL device configuration, in which multiple EL layers are provided in one organic EL device with a charge generation layer sandwiched therebetween, and one or more light-emitting layers are formed in each EL layer.

[0275] The microcavity structure makes it possible to increase the light emission intensity of specific wavelengths in the front direction, thereby reducing power consumption. In the case of a light-emitting device that displays images using four sub-pixels of red, yellow, green, and blue, not only is the yellow light emitted effective in improving brightness, but the microcavity structure that matches the wavelength of each color can be applied to all sub-pixels, resulting in a light-emitting device with good characteristics.

[0276] The light-emitting device of this embodiment has good characteristics because it uses organic EL devices fabricated by the methods for fabricating organic EL devices described in Embodiments 2 and 3. The light-emitting device described above is capable of individually controlling a large number of minute organic EL devices arranged in a matrix, and is therefore suitable for use as a display device for displaying images.

[0277] This embodiment mode can be freely combined with other embodiment modes.

[0278] (Embodiment 6) In this embodiment, examples of electronic devices that include an organic EL device manufactured by the manufacturing method of an organic EL device described in Embodiments 2 and 3 will be described.

[0279] Examples of electronic devices to which the organic EL devices are applied include television sets (also called televisions or television receivers), computer monitors, digital cameras, digital video cameras, digital photo frames, mobile phones (also called mobile phones or mobile phone devices), portable game machines, personal digital assistants, sound players, large game machines such as pachinko machines, etc. Specific examples of these electronic devices are shown below.

[0280] 14A shows an example of a television set. The television set has a display portion 7103 built in a housing 7101. Here, the housing 7101 is supported by a stand 7105. The display portion 7103 can display images, and is configured by arranging organic EL devices, which are manufactured by the manufacturing method of an organic EL device described in Embodiments 2 and 3, in a matrix.

[0281] The television set can be operated using operation switches provided on the housing 7101 or a separate remote control 7110. Operation keys 7109 provided on the remote control 7110 can be used to change channels and volume, and to control an image displayed on the display portion 7103. The remote control 7110 may be provided with a display portion 7107 that displays information output from the remote control 7110. Note that organic EL devices arranged in a matrix and manufactured by the manufacturing method of an organic EL device described in Embodiments 2 and 3 can also be used for the display portion 7107.

[0282] The television device is configured to include a receiver, a modem, etc. The receiver can receive general television broadcasts, and by connecting to a wired or wireless communication network via the modem, it is also possible to perform one-way (from sender to receiver) or two-way (between sender and receiver, or between receivers, etc.) information communication.

[0283] FIG. 14(B) shows a computer including a main body 7201, a housing 7202, a display unit 7203, a keyboard 7204, an external connection port 7205, a pointing device 7206, and the like. This computer is fabricated by using organic EL devices fabricated by the fabrication methods of the organic EL devices described in Embodiments 2 and 3, arranged in a matrix, for the display unit 7203. The computer in FIG. 14(B) may have a configuration as shown in FIG. 14(C). The computer in FIG. 14(C) includes a display unit 7210 instead of the keyboard 7204 and the pointing device 7206. The display unit 7210 is a touch panel type, and input can be performed by operating an input display on the display unit 7210 with a finger or a dedicated pen. The display unit 7210 can display not only the input display but also other images. The display unit 7203 may also be a touch panel. The two screens are connected by a hinge, which can prevent the screens from being scratched or broken during storage or transportation.

[0284] 14(D) shows an example of a mobile terminal. The mobile phone includes a display portion 7402 built in a housing 7401, operation buttons 7403, an external connection port 7404, a speaker 7405, a microphone 7406, and the like. Note that the mobile phone has the display portion 7402 formed by arranging organic EL devices in a matrix, which are manufactured by the manufacturing method of an organic EL device described in Embodiments 2 and 3.

[0285] 14D can be configured so that information can be input by touching the display portion 7402 with a finger or the like. In this case, operations such as making a call or creating an e-mail can be performed by touching the display portion 7402 with a finger or the like.

[0286] The screen of the display unit 7402 has three main modes. The first is a display mode that mainly displays images, the second is an input mode that mainly inputs information such as characters, and the third is a display+input mode that combines the display mode and the input mode.

[0287] For example, when making a call or creating an e-mail, the display portion 7402 may be set to a character input mode mainly for inputting characters, and characters displayed on the screen may be input. In this case, it is preferable to display a keyboard or number buttons on most of the screen of the display portion 7402.

[0288] Furthermore, by providing a detection device having a sensor for detecting tilt, such as a gyroscope or an acceleration sensor, inside the mobile terminal, the orientation of the mobile terminal (portrait or landscape) can be determined and the screen display of the display portion 7402 can be automatically switched.

[0289] The screen mode can be switched by touching the display portion 7402 or by operating the operation buttons 7403 on the housing 7401. The screen mode can also be switched depending on the type of image displayed on the display portion 7402. For example, if the image signal to be displayed on the display portion is moving image data, the display mode is selected, and if it is text data, the input mode is selected.

[0290] In addition, in the input mode, a signal detected by an optical sensor of the display portion 7402 may be detected, and if there is no input by touch operation on the display portion 7402 for a certain period of time, the screen mode may be controlled to switch from the input mode to the display mode.

[0291] The display portion 7402 can also function as an image sensor. For example, personal authentication can be performed by touching the display portion 7402 with a palm or a finger to capture an image of a palm print, fingerprint, or the like. Furthermore, by using a backlight that emits near-infrared light or a sensing light source that emits near-infrared light for the display portion, finger veins, palm veins, or the like can also be captured.

[0292] As described above, the range of application of a light-emitting device including an organic EL device manufactured using the manufacturing method of an organic EL device described in Embodiments 2 and 3 is extremely wide, and this light-emitting device can be applied to electronic devices in a wide range of fields.

[0293] FIG. 15(A) is a schematic diagram showing an example of a cleaning robot.

[0294] The cleaning robot 5100 has a display 5101 arranged on its top surface, multiple cameras 5102 arranged on its side, a brush 5103, and an operation button 5104. Although not shown, the cleaning robot 5100 is also provided with tires, a suction port, and the like on its bottom surface. The cleaning robot 5100 also has various other sensors such as an infrared sensor, an ultrasonic sensor, an acceleration sensor, a piezoelectric sensor, an optical sensor, and a gyro sensor. The cleaning robot 5100 also has wireless communication means.

[0295] The cleaning robot 5100 can move by itself, detect dust 5120, and suck up the dust from a suction port provided on the bottom surface.

[0296] Furthermore, the cleaning robot 5100 can analyze the image captured by the camera 5102 to determine whether there are any obstacles such as walls, furniture, or steps. Furthermore, if the image analysis detects an object that may become tangled in the brush 5103, such as a wire, the rotation of the brush 5103 can be stopped.

[0297] The display 5101 can display the remaining battery level, the amount of dust sucked, etc. The route traveled by the cleaning robot 5100 may be displayed on the display 5101. The display 5101 may also be a touch panel, and an operation button 5104 may be provided on the display 5101.

[0298] The cleaning robot 5100 can communicate with a portable electronic device 5140 such as a smartphone. Images captured by the camera 5102 can be displayed on the portable electronic device 5140. Therefore, the owner of the cleaning robot 5100 can know the state of the room even when he or she is away from home. In addition, the display on the display 5101 can be confirmed on the portable electronic device 5140 such as a smartphone.

[0299] The light-emitting device according to one embodiment of the present invention can be used for the display 5101 .

[0300] The robot 2100 shown in FIG. 15(B) includes a computing device 2110, an illuminance sensor 2101, a microphone 2102, an upper camera 2103, a speaker 2104, a display 2105, a lower camera 2106, an obstacle sensor 2107, and a movement mechanism 2108.

[0301] The microphone 2102 has a function of detecting the user's speaking voice, environmental sounds, etc. The speaker 2104 has a function of emitting sound. The robot 2100 can communicate with the user using the microphone 2102 and the speaker 2104.

[0302] The display 2105 has a function of displaying various information. The robot 2100 can display information desired by the user on the display 2105. The display 2105 may be equipped with a touch panel. The display 2105 may also be a detachable information terminal, which can be installed in a fixed position on the robot 2100 to enable charging and data transfer.

[0303] The upper camera 2103 and the lower camera 2106 have a function of capturing images of the surroundings of the robot 2100. In addition, the obstacle sensor 2107 can detect the presence or absence of an obstacle in the moving direction when the robot 2100 moves forward using the moving mechanism 2108. The robot 2100 can recognize the surrounding environment and move safely using the upper camera 2103, the lower camera 2106, and the obstacle sensor 2107. The light-emitting device of one embodiment of the present invention can be used for the display 2105.

[0304] 15C is a diagram illustrating an example of a goggle-type display. The goggle-type display includes, for example, a housing 5000, a display unit 5001, a speaker 5003, an LED lamp 5004, operation keys (including a power switch or an operation switch), a connection terminal 5006, a sensor 5007 (having a function of measuring 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 ray), a microphone 5008, a second display unit 5002, a support unit 5012, and earphones 5013.

[0305] The light-emitting device of one embodiment of the present invention can be used for the display portion 5001 and the second display portion 5002 .

[0306] The organic EL device manufactured using the manufacturing method of the organic EL device described in Embodiments 2 and 3 can also be installed on the windshield or dashboard of an automobile. Figure 16 shows an example in which the organic EL device manufactured using the manufacturing method of the organic EL device described in Embodiments 2 and 3 is used in the windshield or dashboard of an automobile. Display regions 5200 to 5203 are display regions provided using the organic EL device manufactured using the manufacturing method of the organic EL device described in Embodiments 2 and 3.

[0307] Display region 5200 and display region 5201 are display devices mounted on the windshield of an automobile and equipped with organic EL devices fabricated using the fabrication methods for organic EL devices described in Embodiments 2 and 3. The organic EL devices fabricated using the fabrication methods for organic EL devices described in Embodiments 2 and 3 can be made into a so-called see-through display device, in which the opposite side can be seen through, by fabricating both the anode and cathode using light-transmitting electrodes. A see-through display allows the device to be installed on the windshield of an automobile without obstructing the view. When providing a transistor for driving the device, it is preferable to use a light-transmitting transistor, such as an organic transistor made of an organic semiconductor material or a transistor using an oxide semiconductor.

[0308] Display area 5202 is a display device provided on a pillar and incorporating an organic EL device manufactured by the manufacturing method of an organic EL device described in Embodiments 2 and 3. By displaying an image from an imaging means provided on the vehicle body in display area 5202, the view blocked by the pillar can be complemented. Similarly, display area 5203 provided on the dashboard can complement the view blocked by the vehicle body by displaying an image from an imaging means provided on the outside of the vehicle, thereby compensating for blind spots and improving safety. By displaying an image to complement the invisible parts, safety can be confirmed more naturally and without discomfort.

[0309] The display area 5203 can also provide various other information such as navigation information, speed, RPM, and air conditioning settings. The display items and layout can be changed as needed to suit the user's preferences. This information can also be provided in the display areas 5200 to 5202. The display areas 5200 to 5203 can also be used as lighting devices.

[0310] 17A and 17B show a foldable mobile information terminal 5150. The foldable mobile information terminal 5150 has a housing 5151, a display area 5152, and a bending portion 5153. FIG. 17A shows the mobile information terminal 5150 in an unfolded state. FIG. 17B shows the mobile information terminal in a folded state. Although the mobile information terminal 5150 has a large display area 5152, it is compact and highly portable when folded.

[0311] Display area 5152 can be folded in half by bending portion 5153. Bending portion 5153 is composed of an expandable member and multiple support members, and when folding, the expandable member stretches and bending portion 5153 is folded with a curvature radius of 2 mm or more, preferably 3 mm or more.

[0312] Note that the display region 5152 may be a touch panel (input / output device) equipped with a touch sensor (input device). The light-emitting device of one embodiment of the present invention can be used for the display region 5152.

[0313] 18(A) to 18(C) show a foldable mobile information terminal 9310. Fig. 18(A) shows the mobile information terminal 9310 in an unfolded state. Fig. 18(B) shows the mobile information terminal 9310 in a state in the process of changing from one of an unfolded state and a folded state to the other. Fig. 18(C) shows the mobile information terminal 9310 in a folded state. The mobile 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.

[0314] The display panel 9311 is supported by three housings 9315 connected by hinges 9313. Note that the display panel 9311 may be a touch panel (input / output device) equipped with a touch sensor (input device). The display panel 9311 can be reversibly transformed from an unfolded state of the mobile information terminal 9310 to a folded state by bending the two housings 9315 via the hinges 9313. The light-emitting device of one embodiment of the present invention can be used for the display panel 9311.

[0315] At least a part of the configuration examples exemplified in this embodiment and the corresponding drawings can be combined as appropriate with other configuration examples or drawings.

[0316] This embodiment mode can be implemented by appropriately combining at least a part thereof with other embodiment modes described in this specification. [Example]

[0317] In this example, a light-emitting device 1, which is a light-emitting device of one embodiment of the present invention, was fabricated and its characteristics were measured. The structural formula of an organic compound used in the light-emitting device 1 is shown below. The element structure of the light-emitting device 1 is also shown below.

[0318] [ka]

[0319] [Table 1]

[0320] <<Fabrication of Light-Emitting Device 1>> The light-emitting device 1 shown in this example has a structure in which a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer (a first electron transport layer and a second electron transport layer), a buffer layer, and an electron injection layer are sequentially stacked on a first electrode formed on a substrate, and a second electrode is stacked on the electron injection layer.

[0321] First, a first electrode was formed on a substrate. A silicon substrate was used as the substrate. The electrode area was 4 mm 2 The dimensions of the first electrode were 2 mm x 2 mm. Titanium (50 nm thick), aluminum (70 nm thick), and titanium (6 nm thick) were sequentially deposited by sputtering, and then indium tin oxide containing silicon oxide (ITSO) was deposited by sputtering to a thickness of 10 nm. In this example, the first electrode served as an anode.

[0322] Here, as a pretreatment, the surface of the substrate was washed with water and baked at 200°C for 1 hour. -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 1 hour in the heating chamber of the vacuum deposition apparatus, the substrate was allowed to cool for about 30 minutes.

[0323] Next, a hole injection layer was formed on the first electrode. -4 After reducing the pressure to 10 Pa, PCBBiF and a fluorine-containing electron acceptor material (OCHD-003) with a molecular weight of 672 were co-deposited to form a 10 nm thick film at a weight ratio of PCBBiF:OCHD-003 = 1:0.03.

[0324] Next, a hole transport layer was formed on the hole injection layer by vapor deposition of PCBBiF to a thickness of 10 nm.

[0325] Next, a 40-nm-thick light-emitting layer was formed on the hole-transporting layer by co-evaporation of 8mpTP-4mDBtPBfpm, βNCCP, and Ir(5mppy-d3)2(mbfpypy-d3) at a weight ratio of 8mpTP-4mDBtPBfpm:βNCCP:Ir(5mppy-d3)2(mbfpypy-d3) = 0.6:0.4:0.1.

[0326] Next, electron transport layers (first and second electron transport layers) were formed on the light-emitting layer. The first electron transport layer was formed by vapor deposition of 2mPCCzPDBq to a thickness of 10 nm. The second electron transport layer was formed by vapor deposition of mPPhen2P to a thickness of 13 nm.

[0327] Next, a buffer layer was formed on the electron transport layer by vapor deposition using PTCBI to a thickness of 2 nm.

[0328] Next, processing by photolithography (photolithography process) was performed. The substrate was removed from the vacuum deposition apparatus and exposed to the atmosphere. Then, using trimethylaluminum (TMA) as a precursor and water vapor as an oxidant, aluminum oxide was deposited by the ALD method to a thickness of 30 nm to form an aluminum oxide film.

[0329] A metal film was formed on the aluminum oxide film by sputtering tungsten to a thickness of 54 nm.

[0330] A photoresist was formed on the metal film, and processing was carried out using a photolithography method so that a slit with a width of 3 μm was formed at a position 3.5 μm away from the end of the first electrode.

[0331] Specifically, the metal film was processed using an etching gas containing sulfur hexafluoride (SF6) with a resist mask, and then the photoresist was removed using an ashing gas containing oxygen (O2). The aluminum oxide film was then processed using an etching gas containing fluoroform (CHF3), helium (He), and methane (CH4) in a flow ratio of CHF3:He:CH4 = 3.3:23.7:3. The buffer layer, electron transport layer, light-emitting layer, hole transport layer, and hole injection layer were then processed using an etching gas containing oxygen (O2).

[0332] After processing, a mixed acid solution containing nitric acid, phosphoric acid, etc. was used to remove the metal layer formed by processing the metal film and the aluminum oxide layer formed by processing the aluminum oxide film, thereby exposing the buffer layer. -4 The substrate was introduced into a vacuum deposition apparatus whose inside had been reduced in pressure to about Pa, and heat treatment was carried out at 70° C. for 1.5 hours in a heating chamber of the vacuum deposition apparatus.

[0333] Next, an electron injection layer was formed on the exposed buffer layer by co-depositing lithium fluoride (LiF) and ytterbium (Yb) to a thickness of 1.5 nm at a volume ratio of LiF:Yb=1:0.5.

[0334] Next, a second electrode was formed on the electron injection layer. The second electrode was formed by co-evaporating Ag and Mg in a volume ratio of Ag:Mg=1:0.1 to a thickness of 25 nm, followed by evaporating indium oxide-tin oxide (ITO) to a thickness of 70 nm. In this example, the second electrode served as a cathode.

[0335] Light-emitting device 1 was fabricated through the above steps. This light-emitting device 1 was sealed with a glass substrate in a nitrogen atmosphere glove box to prevent it from being exposed to the atmosphere (a sealant was applied around the element, and UV treatment and heat treatment at 80°C for 1 hour were performed during sealing), and then the initial characteristics of light-emitting device 1 were measured.

[0336] The luminance-current density characteristics of the light-emitting device 1 are shown in Figure 19, the current efficiency-luminance characteristics in Figure 20, the luminance-voltage characteristics in Figure 21, the current-voltage characteristics in Figure 22, and the electroluminescence spectrum in Figure 23. 2 The main characteristics in the vicinity are shown in the table below. Note that a spectroradiometer (SR-UL1R, manufactured by Topcon Corporation) was used to measure the luminance, CIE chromaticity, and electroluminescence spectrum.

[0337] [Table 2]

[0338] 19 to 23 and the above table, it is clear that the light-emitting device 1 is a light-emitting device with good characteristics in which the increase in voltage due to the photolithography process is suppressed by the inclusion of a buffer layer.

[0339] In addition, in Figure 24, the light-emitting device 1 is supplied with 2 mA (50 mA / cm 2 24 shows the change in luminance with respect to the driving time when the device was driven at a constant current of 100 kJ / s. As can be seen from FIG. 24, the light-emitting device 1 has a long life.

[0340] These results demonstrate that the light-emitting device of one embodiment of the present invention has favorable characteristics in which an increase in voltage due to a photolithography process is suppressed due to the inclusion of a buffer layer, and has a long lifetime. [Explanation of symbols]

[0341] 100 Organic Semiconductor Devices 101R First electrode 101C Connecting electrode 101G First electrode 101B first electrode 101 first electrode 102 second electrode 103 EL layer 108 Insulating layer 110R Organic EL Device 110G OLED device 110B Organic EL Device 111 Hole injection layer 112 Hole transport layer 113 Light-emitting layer 114 Electron transport layer 115 Electron injection layer 120R First EL layer 120G First EL layer 120B First EL layer 120Bb EL membrane 120 First EL layer 121 Second EL layer 125 Insulating Layer 125b insulating layer 126 Insulating Layer 126b Insulating layer 130 Connection 131 Barrier Layer 143a Resist mask 144a Aluminum oxide film 145 Aluminum oxide layer 145a Aluminum oxide layer 145b Aluminum oxide layer 145c aluminum oxide layer 146a Metal or metal compound film 147a Metal layer or metal compound layer 148a Buffer film 150 Base film 151 Organic semiconductor layer 151a Organic semiconductor film 151s surface 152 buffer layer 152B buffer layer 152G buffer layer 152R buffer layer 152a Buffer film 153 Aluminum oxide layer 153a Aluminum oxide film 153r Aluminum oxide film 154 Metal layer or metal compound layer 154a Metal or metal compound film 155 Photomask layer 155a Resin membrane 160 Insulating Layer 165 First electrode 166 Second electrode 167 Photoelectric conversion layer 168 Light-emitting layer 200 boards 450 Light-emitting device 601 Source line driver circuit 602 Pixel section 603 Gate line driving circuit 604 Sealing substrate 605 Sealing material 607 Space 608 Wiring 610 Element substrate 611 Switching FET 612 Current control FET 613 First electrode 614 Insulators 616 EL layer 617 Second electrode 623 FET 1001 board 1002 Undercoat insulating film 1003 Gate insulating film 1006 Gate electrode 1007 Gate electrode 1008 gate electrode 1020 First interlayer insulating film 1021 Second interlayer insulating film 1022 Electrode 1024B First electrode 1024G First electrode 1024R First electrode 1024W First electrode 1025 Bulkhead 1028 EL layer 1029 Cathode 1031 Sealing substrate 1032 Sealing material 1033 Base material 1034B Colored layer 1034G colored layer 1034R colored layer 1035 Black Matrix 1036 Overcoat layer 1037 Third interlayer insulating film 1040 pixel section 1041 Drive circuit section 1042 Periphery 2100 Robot 2101 Illuminance sensor 2102 Microphone 2103 Upper Camera 2104 Speaker 2105 Display 2106 Lower Camera 2107 Obstacle Sensor 2108 Moving mechanism 2110 Arithmetic equipment 5000 cabinets 5001 Display section 5002 Second display unit 5003 Speaker 5004 LED lamp 5006 Connection terminal 5007 Sensor 5008 Microphone 5012 Support part 5013 Earphones 5100 Cleaning Robot 5101 Display 5102 Camera 5103 Brush 5104 Operation button 5120 Garbage 5140 Portable electronic devices 5150 Personal Digital Assistant 5151 Case 5152 Display area 5153 Bend 5200 display area 5201 Display area 5202 Display area 5203 Display area 7101 Housing 7103 Display section 7105 Stand 7107 Display section 7109 Operation key 7110 Remote control device 7201 Main unit 7202 Case 7203 Display section 7204 keyboard 7205 External connection port 7206 Pointing Device 7210 Display section 7401 Housing 7402 Display section 7403 Operation button 7404 External connection port 7405 Speaker 7406 Microphone 9310 Mobile Information Terminal 9311 Display Panel 9313 Hinge 9315 Housing

Claims

1. a first electrode, a second electrode, a first organic semiconductor layer, and a buffer layer; the first organic semiconductor layer is located between the first electrode and the second electrode; the buffer layer is located between the first organic semiconductor layer and the second electrode; An organic semiconductor device, wherein a side surface of the first organic semiconductor layer and a side surface of the buffer layer have approximately the same surface.

2. A semiconductor device comprising a first electrode, a second electrode, a first organic semiconductor layer, and a buffer layer, the first organic semiconductor layer is located between the first electrode and the second electrode; the buffer layer is located between the first organic semiconductor layer and the second electrode; a side surface of the first organic semiconductor layer and a side surface of the buffer layer have approximately the same surface; the buffer layer has a thickness of 0.1 nm or more and 5 nm or less; an organic semiconductor device, wherein the distance between the side surface of the first organic semiconductor layer and the side surface of the organic semiconductor layer of the adjacent organic semiconductor device is 2 μm or more and 5 μm or less.

3. In claim 1 or 2, The organic semiconductor device, wherein the buffer layer comprises a metal.

4. In claim 1 or 2, The buffer layer comprises an organometallic compound.

5. In claim 1 or 2, The buffer layer comprises an organic compound.

6. In claim 1 or 2, The organic semiconductor device, wherein the buffer layer is formed by laminating a first buffer layer and a second buffer layer.

7. In any one of claims 1 to 6, a second organic semiconductor layer; the second organic semiconductor layer is located between the buffer layer and the second electrode; An organic semiconductor device, wherein a side surface of the second organic semiconductor layer does not have the same surface as a side surface of the first organic semiconductor layer and a side surface of the buffer layer.

8. a first electrode, a second electrode, a first organic semiconductor layer, and a buffer layer; the first organic semiconductor layer has a light-emitting layer; the first organic semiconductor layer is located between the first electrode and the second electrode; the buffer layer is located between the first organic semiconductor layer and the second electrode; an organic EL device, wherein a side surface of the first organic semiconductor layer and a side surface of the buffer layer are substantially flush with each other;

9. In claim 8, The organic electroluminescent device, wherein the buffer layer comprises a metal.

10. In claim 8, The organic electroluminescent device, wherein the buffer layer comprises an organometallic compound.

11. In claim 8, The organic electroluminescent device, wherein the buffer layer comprises an organic compound.

12. In claim 8, The organic EL device, wherein the buffer layer is formed by laminating a first buffer layer and a second buffer layer.

13. In any one of claims 8 to 12, a second organic semiconductor layer; the second organic semiconductor layer is located between the buffer layer and the second electrode; an organic electroluminescent device, wherein a side surface of the second organic semiconductor layer does not have the same surface as a side surface of the first organic semiconductor layer and a side surface of the buffer layer;

14. A light-emitting device comprising the organic EL device according to any one of claims 8 to 12 and a transistor or a substrate.

15. An electronic device comprising the light-emitting device according to claim 14 and a detection unit, an input unit, or a communication unit.

16. A lighting device comprising the light-emitting device according to claim 14 and a housing.

Images