Liquid composition, method for manufacturing organic light-emitting element, organic light-emitting element, and display device

Abstract

Provided is a liquid composition that can form a constituent layer with excellent film thickness uniformity and that can produce an organic light-emitting device with excellent luminous efficiency without adversely affecting its lifespan. [Solution] A liquid composition used for forming constituent layers of an organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are stacked. The liquid composition contains a compound having a number-average molecular weight of 1,050 or less and a repeating structural unit represented by formula (1), and an organic solvent. TIFF2026043501000017.tif27170

Description

[Technical Field]

[0001] The present invention relates to a liquid composition, a method for producing an organic light-emitting element, an organic light-emitting element, and a display device. [Background technology]

[0002] An organic light-emitting device (OLED) is an electronic device that has a pair of electrodes consisting of a first electrode and a second electrode, and an organic compound layer disposed between the pair of electrodes. By injecting electrons and holes from the pair of electrodes into the organic compound layer, respectively, the light-emitting organic compound in the organic compound layer can be activated from the ground state to an excited state. When the excited organic compound returns to the ground state, it can emit excess energy as light.

[0003] Organic light-emitting devices are also called organic electroluminescence devices or organic EL devices. Organic light-emitting devices can generally be manufactured by a dry process, such as a vacuum deposition method, in which materials for forming various functional layers, such as organic compound layers, inorganic compound layers, and electrode (layers), are heated and vapor-deposited on a substrate under high vacuum. However, because uniform vapor deposition on a large-area substrate is difficult, and in terms of material utilization efficiency and manufacturing costs, methods for manufacturing organic light-emitting devices by wet processes, such as a printing method, have also been studied in recent years.

[0004] In the wet process, an organic compound layer is formed by applying a liquid composition to a predetermined location by coating or other methods and then drying the composition. Therefore, techniques for making the thickness of the organic compound layer more uniform have been investigated. For example, a composition for forming an organic compound layer containing an additive, such as a fluorine-based compound, to improve leveling properties has been proposed (Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-102671 Summary of the Invention [Problem to be solved by the invention]

[0006] The present inventors have investigated compositions containing the additives proposed in Patent Document 1. As a result, it has been found that while the thickness uniformity of the formed organic compound layer is improved, the external quantum efficiency (luminous efficiency) of the organic light-emitting element is reduced and the life of the organic light-emitting element is shortened.

[0007] Therefore, an object of the present invention is to provide a liquid composition that can form a constituent layer with excellent film thickness uniformity and that can produce an organic light-emitting element with excellent luminous efficiency without adversely affecting its lifespan. Another object of the present invention is to provide a method for producing an organic light-emitting element that can produce an organic light-emitting element with a constituent layer with excellent film thickness uniformity, which has a long lifespan and excellent luminous efficiency. Still another object of the present invention is to provide an organic light-emitting element with a constituent layer with excellent film thickness uniformity, which has a long lifespan and excellent luminous efficiency, and a display device using this organic light-emitting element. [Means for solving the problem]

[0008] That is, according to the present invention, there is provided a liquid composition used for forming a constituent layer of an organic light-emitting device having a laminate structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, the liquid composition comprising a compound having a number-average molecular weight of 1,050 or less and having a repeating structural unit represented by the following formula (1), and an organic solvent:

[0009] TIFF2026043501000001.tif27170 [Effects of the Invention]

[0010] According to the present invention, a liquid composition can be provided that can form a constituent layer with excellent film thickness uniformity and that can produce an organic light-emitting element with excellent luminous efficiency without adversely affecting its lifespan. Furthermore, according to the present invention, a method for producing an organic light-emitting element can be provided that can produce an organic light-emitting element with a constituent layer with excellent film thickness uniformity, that has a long lifespan, and excellent luminous efficiency. Furthermore, according to the present invention, an organic light-emitting element with a constituent layer with excellent film thickness uniformity, that has a long lifespan, and excellent luminous efficiency, and a display device using this organic light-emitting element can be provided. [Brief explanation of the drawings]

[0011] [Figure 1A] 1 is a schematic cross-sectional view illustrating an example of a pixel constituting a display device of the present invention. [Figure 1B] 1 is a schematic cross-sectional view showing an embodiment of a display device of the present invention. [Figure 2] FIG. 10 is a schematic diagram illustrating another embodiment of the display device of the present invention. [Figure 3A] FIG. 1 is a schematic diagram illustrating an example of an imaging device. [Figure 3B] FIG. 1 is a schematic diagram illustrating an example of a portable device. [Figure 4A] FIG. 10 is a schematic diagram illustrating another embodiment of the display device of the present invention. [Figure 4B] FIG. 10 is a schematic diagram illustrating another embodiment of the display device of the present invention. [Figure 5A] FIG. 1 is a schematic diagram illustrating an example of a lighting device. [Figure 5B] FIG. 1 is a schematic diagram illustrating an example of a moving body. [Figure 6A] FIG. 1 is a schematic diagram illustrating an example of a wearable device. [Figure 6B] FIG. 10 is a schematic diagram showing another example of a wearable device. DETAILED DESCRIPTION OF THE INVENTION

[0012] The present invention will be described in further detail below with reference to preferred embodiments. Physical property values ​​are values ​​at room temperature (25°C) unless otherwise specified. Furthermore, the term "average film thickness" refers to the average thickness of each layer (film) in the region that emits light when a voltage is applied to the organic light-emitting device.

[0013] The present inventors have conducted extensive research into liquid compositions capable of forming constituent layers with excellent film thickness uniformity and capable of producing organic light-emitting devices with excellent luminous efficiency without adversely affecting their lifetime. As a result, they have found that the following composition is effective, leading to the present invention. Specifically, the liquid composition of the present invention is a liquid composition used to form constituent layers of an organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and an emitting layer are stacked. The liquid composition of the present invention contains a compound having a number-average molecular weight of 1,050 or less and having a repeating structural unit represented by the following formula (1), and an organic solvent.

[0014] TIFF2026043501000002.tif27170

[0015] A compound having a repeating structural unit represented by formula (1) (hereinafter referred to as a "chlorotrifluoroethylene compound" or simply as a "compound") has excellent leveling properties and very strong surface migration properties. Therefore, when a liquid composition containing this compound is applied and dried to form a constituent layer of an organic light-emitting device, such as a light-emitting layer, much of the compound migrates to the surface of the constituent layer that is formed, and almost no compound remains inside the constituent layer. Furthermore, because the chlorotrifluoroethylene compound has excellent leveling properties, it is possible to suppress variations in the surface state of the constituent layer that has migrated to the surface, and form a constituent layer with excellent film thickness uniformity.

[0016] Furthermore, even when a trace amount of a chlorotrifluoroethylene compound is used, a constituent layer with excellent film thickness uniformity can be formed. Therefore, there is substantially no adverse effect on the luminous efficiency or lifespan of an organic light-emitting device having a constituent layer such as an emitting layer formed using the liquid composition of the present invention. Furthermore, the chlorotrifluoroethylene compound is a liquid under an environment of room temperature (25°C) and normal humidity (50% RH). Therefore, since the liquid composition containing the chlorotrifluoroethylene compound is a uniform liquid, it is useful as a material for forming a constituent layer such as an emitting layer by a wet process.

[0017] <Liquid composition> The liquid composition of the present invention is a liquid composition used for forming constituent layers of an organic light-emitting device having a laminate structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated. The liquid composition of the present invention contains a compound having a number-average molecular weight of 1,050 or less and having a repeating structural unit represented by the following formula (1), and an organic solvent. The liquid composition of the present invention will be described in detail below.

[0018] TIFF2026043501000003.tif27170

[0019] (chlorotrifluoroethylene compounds) A compound (chlorotrifluoroethylene compound) having a number-average molecular weight of 1,050 or less and having a repeating structural unit represented by formula (1) is liquid under conditions of room temperature (25°C) and normal humidity (50% RH). The number-average molecular weight of the chlorotrifluoroethylene compound is preferably 400 or more and 700 or less. By using a chlorotrifluoroethylene compound whose number-average molecular weight falls within the above range, it is possible to further improve the film uniformity of the formed constituent layer, and also to manufacture an organic light-emitting device having excellent luminous efficiency and lifespan.

[0020] The viscosity of the chlorotrifluoroethylene compound at 25°C is preferably 10 mPa·s or more and 30 mPa·s or less. Furthermore, the content (mass %) of the chlorotrifluoroethylene compound in the liquid composition is preferably 0.02 mass % or less, and more preferably 0.001 mass % or more and 0.01 mass % or less, based on the total mass of components other than the organic solvent. If the content of the chlorotrifluoroethylene compound in the liquid composition is too high, excess compound remaining in the resulting constituent layers, such as the light-emitting layer, may have some effect on the luminous efficiency and lifespan of the resulting organic light-emitting device.

[0021] (organic solvent) The organic solvent is a component for dissolving the chlorotrifluoroethylene compound well.Examples of organic solvents include aromatic or halogenated aromatic hydrocarbon solvents such as benzene, cyclohexylbenzene, toluene, 4-methoxytoluene, o-xylene, p-xylene, mesitylene, ethylbenzene, and chlorobenzene; aliphatic hydrocarbons such as n-heptane, n-hexane, and cyclohexane; ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 1,4-dioxane, and 1,2-dimethoxyethane; acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentane, and the like. Ketone solvents such as methyl benzoate, methyl benzoate, ethyl lactate, and γ-butyrolactone; halogenated hydrocarbon solvents such as methylene chloride, dichloromethane, 1,2-dichloroethane, and chloroform; amide solvents such as N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone; methanol, ethanol, isopropanol, and n-propanol Examples of suitable solvents include alcohol-based solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol diglycidyl ether, propylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol monomethyl ether, and propylene glycol monomethyl ether acetate; and glycol-based solvents such as ethylene glycol, propylene glycol, hexylene glycol, 1,3-octylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, 1,3-butanediol, 2,3-butanediol, and 1,4-butanediol.

[0022] (Other ingredients) The liquid composition further contains, for example, materials for forming a hole injection layer, a hole transport layer, or a light-emitting layer. Specifically, the liquid composition for forming the hole injection layer and the liquid composition for forming the hole transport layer contain a hole injection transport compound. Furthermore, the liquid composition for forming the light-emitting layer contains a light-emitting material, a host material, a light-emitting assist material, and the like. Details of the materials for forming these constituent layers will be described later.

[0023] <Organic light-emitting element> The organic light-emitting device of the present invention has a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and an emitting layer are laminated. At least one layer selected from the group consisting of the hole injection layer, the hole transport layer, and the emitting layer contains a compound (chlorotrifluoroethylene compound) having a number-average molecular weight of 1,050 or less and having a repeating structural unit represented by the following formula (1). The organic light-emitting device of the present invention will be described in detail below.

[0024] TIFF2026043501000004.tif27170

[0025] (Structure of organic light-emitting element) An organic light-emitting element has a laminated structure in which multiple constituent layers are stacked. The multiple constituent layers include a hole injection layer, a hole transport layer, and a light-emitting layer. The constituent layers including the hole injection layer, the hole transport layer, and the light-emitting layer are collectively referred to as an "organic compound layer." A specific example of the laminated structure of an organic light-emitting element is a structure in which a substrate, an insulating layer, a first electrode, an organic compound layer, and a second electrode are stacked in this order. A protective layer, a color filter, and the like may be further provided on the second electrode (in the opposite direction to the substrate). When a color filter is provided, a planarizing layer may be further provided between the protective layer and the color filter. The constituent layer containing a chlorotrifluoroethylene compound can be formed by applying and drying the aforementioned liquid composition. From the viewpoint of luminous efficiency, the constituent layer containing a chlorotrifluoroethylene compound is preferably a light-emitting layer.

[0026] [substrate] The substrate can be made of a material such as quartz, glass, silicon, resin, or metal. Components such as switching elements (e.g., transistors) and wiring can be provided on the substrate, and an insulating layer can be further provided on these components. The insulating layer is a layer formed of a material that can form contact holes to ensure electrical continuity between the anode and the wiring, and that can ensure insulation from unconnected wiring. Examples of materials that can form such an insulating layer include resins such as polyimide; silicon compounds such as silicon oxide and silicon nitride; and the like.

[0027] [electrode] The pair of electrodes consists of a first electrode and a second electrode. One of the first electrode and the second electrode is an anode, and the other is a cathode. When a voltage is applied in a direction in which the organic light-emitting element emits light, the electrode with a higher potential becomes the anode, and the other becomes the cathode. In other words, the electrode that supplies holes to the light-emitting layer is the anode, and the electrode that supplies electrons is the cathode. Each electrode may be formed of one type of material, or may be formed of two or more types of materials. Furthermore, each electrode may be a single layer, or may be a laminate of two or more layers.

[0028] The anode is preferably made of a material with a high work function, such as metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten; metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide; mixtures and alloys thereof; and conductive polymers such as polyaniline, polypyrrole, and polythiophene.

[0029] When used as a reflective electrode, the anode can be made of metals such as chromium, aluminum, silver, titanium, tungsten, and molybdenum; alloys or laminates thereof; or the like. When used as a transparent electrode, the anode can be made of metal oxides such as indium tin oxide (ITO) and indium zinc oxide. Photolithography can be used to form the anode.

[0030] The cathode is preferably formed from a material with a low work function. Examples of such materials include alkali metals such as lithium; alkaline earth metals such as calcium; other metals such as aluminum, titanium, manganese, silver, lead, and chromium; and oxides, mixtures, and alloys thereof. Examples of alloys include magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver. Examples of metal oxides include indium tin oxide (ITO). Silver and silver alloys are preferred as materials for forming the cathode, and silver alloys are even more preferred to suppress silver aggregation. As long as silver aggregation can be suppressed, the ratio of silver to other metals contained in the silver alloy is not important. For example, a silver:other metal ratio of approximately 1:1 (mass ratio) may be used. Photolithography can be used to form the cathode.

[0031] The cathode may be formed of a metal oxide such as indium tin oxide (ITO) to make the organic light-emitting element a top-emission element, or the reflective electrode may be formed of a metal such as aluminum (Al) to make the organic light-emitting element a bottom-emission element. Photolithography or sputtering can be used to form the cathode. Among these, sputtering (DC or AC) is preferred for forming the cathode. A cathode (film) formed by sputtering has excellent coverage and can reduce resistance.

[0032] [Protective layer] A protective layer can be provided on the cathode (second electrode). By providing a protective layer by adhering glass having a moisture absorbent layer on the cathode, it is possible to prevent water and other substances from penetrating the organic compound layer, thereby suppressing display defects. Furthermore, by providing a passivation film such as silicon nitride as a protective layer on the cathode, it is possible to prevent water and other substances from penetrating the organic compound layer. The protective layer can be formed by a chemical vapor deposition (CVD) method or the like. Alternatively, after forming a film by chemical vapor deposition, a two-layer protective layer can be formed by atomic layer deposition (ALD). For example, after forming the cathode, the substrate can be transported to another chamber while maintaining a vacuum, and a silicon nitride film can be formed as a protective layer by CVD. The average thickness of the protective layer is preferably 1 μm or more and 10 μm or less.

[0033] [Color Filter] A color filter can be provided on the protective layer. A color filter corresponding to the size of the organic light-emitting element can be provided on a separate substrate and then bonded to the substrate on which the organic light-emitting element is provided, or the color filter can be patterned by photolithography. The color filter can be formed from a polymer material or the like.

[0034] [Planarization layer] A planarizing layer can be provided between the protective layer and the color filter. Examples of materials for the planarizing layer include organic compounds. It is particularly preferable to form the planarizing lower layer using a polymeric organic compound such as a resin. Planarizing layers may be provided above and below (on both sides of) the color filter, and the materials for the planarizing layers may be the same or different. Examples of materials for the planarizing layer include resins such as polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenolic resin, epoxy resin, silicone resin, and urea resin.

[0035] [Counter substrate] An opposing substrate can be provided on the planarization layer. The opposing substrate is a substrate provided at a position corresponding to the aforementioned substrate. Examples of materials for forming the opposing substrate include the same materials as those for forming the substrate.

[0036] [Organic compound layer] The organic compound layer includes a hole injection layer, a hole transport layer, and an emitting layer. The organic compound layer may further include an electron blocking layer, a hole / exciton blocking layer, an electron transport layer, an electron injection layer, etc. The hole transport layer and the electron transport layer are also called charge transport layers. The emitting layer may be a single layer or a laminate of two or more layers.

[0037] The average thickness of each layer constituting the organic compound layer is preferably 1 nm or more and 10,000 nm or less (10 μm or less), and more preferably 10 nm or more and 100 nm or less from the viewpoint of further improving the light-emitting properties.

[0038] The average film thickness of each layer (film) in this specification is the average value of thicknesses measured at any five points using a stylus profilometer. As the stylus profilometer, for example, a commercially available device such as the product name "P-16+" (manufactured by KLA-Tencor) can be used.

[0039] [Light-emitting layer] The light-emitting layer can be formed from a light-emitting material, a host material, and a light-emitting assist material. Examples of the light-emitting material include fused ring compounds such as fluorene derivatives, naphthalene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, anthracene derivatives, and rubrene, as well as polymer derivatives such as quinacridone derivatives, coumarin derivatives, stilbene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, iridium complexes, platinum complexes, rhenium complexes, copper complexes, europium complexes, ruthenium complexes, poly(phenylenevinylene) derivatives, poly(fluorene) derivatives, and poly(phenylene) derivatives.

[0040] Examples of the host material and the light-emitting assist material include aromatic hydrocarbon compounds, derivatives of aromatic hydrocarbon compounds, carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organic aluminum complexes such as tris(8-quinolinolato)aluminum, and organic beryllium complexes. The host material preferably has an anthracene skeleton, a tetracene skeleton, a perylene skeleton, a fluorene skeleton, or a pyrene skeleton in its molecular structure.

[0041] [Hole injection layer, hole transport layer] The hole injection layer and the hole transport layer can be formed from a hole injection transport compound. Examples of the hole injection transport compound include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. These hole injection transport materials can also be used as materials for forming the electron blocking layer.

[0042] [Electron transport layer] The electron transporting layer can be formed from an electron transporting material. Examples of the electron transporting material include oxadiazole derivatives, oxazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, and organoaluminum complexes, as well as fused ring compounds such as fluorene derivatives, naphthalene derivatives, chrysene derivatives, and anthracene derivatives. These electron transporting materials can also be used as materials for forming the hole blocking layer.

[0043] [Electron injection layer] An electron injection material can be used as a material for forming the electron injection layer. The electron injection material is selected taking into consideration the balance between ease of electron injection from the cathode and hole injection. Examples of the electron injection material include compounds containing alkali metals such as lithium fluoride, lithium complexes such as lithium quinolinol, benzimidazolidene derivatives, imidazolidene derivatives, fulvalene derivatives, and acridine derivatives. These organic compounds also include n-type dopants and reducing dopants.

[0044] (Applications of organic light-emitting devices) The organic light-emitting element of the present invention can be used as a component of a display device or a lighting device, for example, as an exposure light source for an electrophotographic image recording device, as a backlight for a liquid crystal display device, or as a light-emitting device having a white light source and a color filter.

[0045] <Method of manufacturing organic light-emitting element> The method for producing an organic light-emitting device of the present invention is a method for producing an organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and an emitting layer are laminated. The production method of the present invention includes a step of applying and drying the liquid composition described above to form at least one layer selected from the group consisting of the hole injection layer, the hole transport layer, and the emitting layer. The production method of the present invention is described in detail below.

[0046] (Constituent layer formation process) The manufacturing method of the present invention includes a step of forming at least one layer (constituent layer) selected from the group consisting of a hole injection layer, a hole transport layer, and a light-emitting layer. In this step, an organic compound layer such as a light-emitting layer is formed by a so-called wet process, in which the aforementioned liquid composition containing a chlorotrifluoroethylene compound is applied and dried. Examples of methods for applying the liquid composition to a predetermined location include coating methods such as spin coating, casting, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, capillary coating, and spray coating; and printing methods such as screen coating, flexography, offset coating, and inkjet printing. Among these, spray coating and inkjet printing are preferred, with inkjet printing being more preferred. By employing these methods, organic light-emitting devices with larger areas can be easily manufactured.

[0047] After applying the liquid composition by a wet process, it is preferable to dry and remove the organic solvent in the liquid composition to form organic compound layers such as a hole injection layer, a hole transport layer, and an emitting layer. Drying conditions can be appropriately set depending on the constituent materials of the organic compound layer and the type of organic solvent. Drying is preferably carried out in an air atmosphere or an inert gas atmosphere such as nitrogen or argon. The heating temperature during drying is preferably 100°C or higher and 250°C or lower, and more preferably 110°C or higher and 200°C or lower. The heating time is preferably 5 minutes or higher and 60 minutes or lower. The pressure during drying may be normal pressure (1 atmosphere) or reduced pressure (100 Pa to 0.1 MPa).

[0048] The liquid composition or other liquid for forming an organic compound layer may further contain a binder resin, if necessary. Examples of the binder resin include polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin. Furthermore, if necessary, the liquid composition containing a chlorotrifluoroethylene compound or other liquid for forming an organic compound layer may contain known additives such as a plasticizer, an antioxidant, and an ultraviolet absorber.

[0049] The constituent layer formed without using a liquid composition containing a chlorotrifluoroethylene compound can be formed by a wet process as well as a dry process. Examples of the dry process include vacuum deposition, ionization deposition, sputtering, and plasma deposition. Among them, vacuum deposition, ionization deposition, spray coating, and inkjet deposition are preferred, and inkjet deposition is more preferred. By adopting these methods, organic light-emitting devices with a larger area can be easily manufactured.

[0050] <Display device> The display device of the present invention is a device including a plurality of pixels, at least one of which includes the organic light-emitting element described above and a transistor connected to the organic light-emitting element. The display device of the present invention will be described in detail below.

[0051] The display device has an image input unit that inputs image information from, for example, an area CCD, a linear CCD, or a memory card, and an information processing unit that processes the input image information. A CCD is a charge-coupled device. The display device may be an image information processing device that displays the input image information on a display unit. The display unit of an imaging device, inkjet recording device, or the like may have a touch panel function. Examples of driving methods for the touch panel function include an infrared method, a capacitance method, a resistive film method, and an electromagnetic induction method. The display device may be used in the display unit of a so-called hybrid recording device.

[0052] Next, details of the display device of the present invention will be described with reference to the drawings. FIG. 1A is a schematic cross-sectional view illustrating an example of a pixel constituting the display device of the present invention. The pixel shown in FIG. 1A includes subpixels 10R, 10G, and 10B. The subpixels 10R, 10G, and 10B are distinguished by their emitted colors. The emitted colors may be distinguished and determined by the wavelength of light emitted from the light-emitting layer, or may be determined by selective transmission or color conversion of light emitted from the subpixels 10R, 10G, and 10B by color filters 7R, 7G, and 7B. Each of the subpixels 10R, 10G, and 10B includes an interlayer insulating layer 1, a reflective electrode 2 serving as a first electrode provided on the interlayer insulating layer 1, an insulating layer 3 covering the edges of the reflective electrode 2, and an organic semiconductor layer 4 covering the first electrode and the insulating layer. Each of the subpixels 10R, 10G, and 10B further includes a transparent electrode 5, a protective layer 6, and color filters 7R, 7G, and 7B.

[0053] A transistor or a capacitor may be disposed below or within the interlayer insulating layer 1. The transistor and the first electrode may be electrically connected via a contact hole (not shown). The insulating layer 3 is also called a bank or a pixel separation film. The insulating layer 3 covers the edge of the first electrode (reflective electrode 2) and is disposed so as to surround the first electrode. The portion of the first electrode where the insulating layer 3 is not disposed is connected to the organic semiconductor layer 4 and forms a light-emitting region. The organic semiconductor layer (organic compound layer) 4 includes a hole injection layer 41, a hole transport layer 42, an intermediate layer 43, an emitting layer 44, and an electron transport layer 45. The second electrode may be a transparent electrode, a reflective electrode, or a semi-transparent electrode. The protective layer 6 is a layer for reducing the penetration of liquid components such as water into the organic compound layer. The protective layer may be composed of multiple layers. When the protective layer is composed of multiple layers, the multiple layers may include an inorganic compound layer and an organic compound layer.

[0054] The color filters 7R, 7G, and 7B are divided according to color. The color filters may be formed on a planarization film (not shown). A resin protective layer (not shown) may be disposed on the color filters. Furthermore, the color filters may be formed on a protective layer 6, or may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0055] FIG. 1B is a schematic cross-sectional view showing one embodiment of a display device of the present invention. The display device 100 shown in FIG. 1B includes an organic light-emitting element 26 and an active element 18, such as a thin-film transistor (TFT), connected to the organic light-emitting element 26. A transistor such as a TFT is an example of an active element. The display device 100 includes a substrate 11 made of a material such as glass or silicon, and an insulating layer 12 provided on the substrate 11. An active element 18, such as a TFT, is disposed on the insulating layer 12. The active element 18 includes a gate electrode 13, a gate insulating film 14, a semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is provided on top of the active element 18. An anode 21 and a source electrode 17 constituting the organic light-emitting element 26 are connected via a contact hole 20 provided in the insulating film 19. Note that the electrical connection between the electrodes (anode and cathode) included in the organic light-emitting element and the electrodes (source and drain electrodes) included in the active element is not limited to the configuration shown in FIG. 1B. In other words, it is sufficient that the anode or cathode is electrically connected to the TFT source electrode or drain electrode.

[0056] Although the display device 100 shown in FIG. 1B includes an organic semiconductor layer 22 formed of a single layer, the organic semiconductor layer may include multiple layers. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce deterioration of the organic light-emitting element 26. Examples of the active element 18 constituting the display device 100 include transistors using a single-crystal silicon wafer and thin-film transistors having an active layer on an insulating surface of a substrate. Examples of the active layer include non-single-crystal silicon such as single-crystal silicon, amorphous silicon, and microcrystalline silicon, and non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide.

[0057] Active elements such as transistors that constitute the display device may be formed within a substrate such as a silicon substrate. "Formed within a substrate" means that the transistors are formed by processing the substrate such as a silicon substrate. In other words, the substrate and the transistors may be formed integrally.

[0058] The light emission brightness of the organic light-emitting element is controlled by a TFT, which is an example of an active element (switching element). By providing multiple organic light-emitting elements in a plane, an image can be displayed using the light emission brightness of each of the multiple organic light-emitting elements. The switching element may be a TFT, a transistor formed from low-temperature polysilicon, or an active matrix driver formed on a substrate such as a silicon substrate. If the size of the display unit is, for example, about 0.5 inches, it is preferable to provide the organic light-emitting element on a silicon substrate.

[0059] FIG. 2 is a schematic diagram showing another embodiment of a display device of the present invention. The display device 1000 shown in FIG. 2 includes an upper cover 1001 and a lower cover 1009 disposed opposite each other. The display device 1000 further includes a touch panel 1003, a display panel 1005, a frame 1006, a circuit board 1007, and a battery 1008 disposed between the upper cover 1001 and the lower cover 1009. Flexible printed circuits (FPCs) 1002 and 1004 are connected to the touch panel 1003 and the display panel 1005, respectively. Transistors are printed on the circuit board 1007. When the display device is a portable device, a battery 1008 is typically provided. Note that the battery 1008 may be provided in a different position.

[0060] The display device may have red (R), green (G), and blue (B) color filters. The red, green, and blue color filters may be arranged in a delta array, a stripe array, or a mosaic array. The display device may be used in the display unit of a mobile terminal. When the display device is used in the display unit of a mobile terminal, the display device may have both a display function and an operation function. Examples of mobile terminals include mobile phones such as smartphones, tablets, and head-mounted displays.

[0061] The display device can be used as a display unit of an imaging device that includes an optical unit having multiple lenses and an imaging element that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the imaging element. The display unit may be disposed in an exposed state outside the imaging device, or may be disposed in a state housed within the viewfinder. Examples of imaging devices include digital cameras and digital video cameras. An imaging device can also be called a photoelectric conversion device.

[0062] 3A is a schematic diagram showing an example of an imaging device. The imaging device 1100 shown in FIG. 3A includes a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. A display device can be used as the viewfinder 1101. The display device may display not only the captured image but also environmental information and imaging instructions. Examples of environmental information include the intensity of external light, the direction of external light, the moving speed of the subject, and the possibility that the subject will be blocked by an obstruction.

[0063] Since the optimum timing for capturing an image is a short time, it is preferable to be able to display information quickly. Organic light-emitting elements have a fast response speed, making them suitable for use in display devices. The image capturing device 1100 has an optical section (not shown). The optical section has multiple lenses that form an image on an image capturing element housed in a housing 1104. The focus of the multiple lenses can be adjusted by controlling their relative positions. The relative positions of the multiple lenses can also be controlled by automatic operation.

[0064] FIG. 3B is a schematic diagram showing an example of a portable device. The portable device 1200 shown in FIG. 3B includes a display unit 1201, an operation unit 1202, and a housing 1203. An organic light-emitting element can be used for the display unit 1201. The housing 1203 includes a circuit, a printed circuit board having the circuit, a battery, a communication unit, and the like. The operation unit 1202 may be a button or a touch panel type reaction unit. The operation unit 1202 may be a biometric recognition unit that recognizes a fingerprint to perform operations such as unlocking. A portable device further including a communication unit can also be called a communication device. The portable device 1200 may further include a lens and an imaging element to have a camera function. An image captured by the camera function is displayed on the display unit 1201. Examples of the portable device 1200 include a smartphone and a laptop computer.

[0065] FIG. 4A is a schematic diagram showing another embodiment of the display device of the present invention. The display device 1300 shown in FIG. 4A is a monitor for a television, a personal computer, or the like. The display device 1300 includes a frame 1301, a display unit 1302, and a base 1303 that supports the display unit 1302. An organic light-emitting element can be used in the display unit 1302. The form of the base 1303 is not limited to that shown in FIG. 4A, and the bottom side of the frame 1301 may also serve as the base. Furthermore, the frame 1301 and the display unit 1302 may be curved. When the frame 1301 or the display unit 1302 is curved, the radius of curvature thereof is preferably 5,000 mm or more and 6,000 mm or less.

[0066] FIG. 4B is a schematic diagram showing another embodiment of a display device of the present invention. The display device 1310 shown in FIG. 4B is a so-called foldable display device that is configured to be bendable. The display device 1310 includes a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. Organic light-emitting elements can be used for the first display unit 1311 and the second display unit 1312. The first display unit 1311 and the second display unit 1312 may be a single display unit without any seams. The first display unit 1311 and the second display unit 1312 can be separated by the bending point 1314. The first display unit 1311 and the second display unit 1312 may display different images or a single image.

[0067] FIG. 5A is a schematic diagram illustrating an example of a lighting device. The lighting device 1400 shown in FIG. 5A includes a housing 1401, a light source 1402, a circuit board 1403, an optical film 1404, and a light diffusion unit 1405. An organic light-emitting element can be used for the light source 1402. The optical film 1404 may be a filter that improves the color rendering of the light source. The light diffusion unit 1405 can effectively diffuse light from the light source, such as for lighting up, and deliver the light over a wide area. The optical filter and the light diffusion unit may be provided on the light output side of the lighting. If necessary, a cover may be provided on the outermost surface.

[0068] A lighting device is, for example, a device that illuminates a room and includes a light source and a member that transmits light emitted by the light source. Lighting devices may emit not only white or daylight white, but also any color from blue to red. "White" refers to a color with a color temperature of approximately 4,200 K, and "daylight white" refers to a color with a color temperature of approximately 5,000 K. The lighting device may further include a dimming circuit that adjusts the light. The lighting device may further include a power supply circuit connected to the organic light-emitting element used as the light source. The power supply circuit is a circuit that converts AC voltage to DC voltage. The lighting device may further include a light diffusion unit or a color filter as a member that transmits light emitted by the light source. The lighting device may also include a heat dissipation unit that dissipates heat from within the device to the outside. Examples of materials that make up the heat dissipation unit include metals with high specific heat and liquid silicon.

[0069] FIG. 5B is a schematic diagram showing an example of a moving object. The moving object shown in FIG. 5B is an automobile 1500 equipped with a lamp such as a tail lamp 1501 that lights up when the brakes are applied. An organic light-emitting element can be used in the tail lamp 1501. The tail lamp 1501 may be equipped with a protective member that protects the organic light-emitting element. The protective member may be made of a transparent material that has a certain degree of strength. Examples of such a material include a resin material such as polycarbonate. The resin material such as polycarbonate may contain a furandicarboxylic acid derivative or an acrylonitrile derivative.

[0070] The automobile 1500 may further include a body 1503 and a window 1502 provided in the body 1503. The window 1502 may be a transparent display using organic light-emitting elements, unless it is used to check the front and rear of the automobile 1500. Components such as electrodes that constitute a transparent display using organic light-emitting elements are made of transparent materials.

[0071] 5B, examples of the mobile object other than the automobile 1500 include a ship, an aircraft, and a drone. The mobile object may include a body and a light fixture that emits light to indicate the position of the body. An organic light-emitting element can be used for the light fixture.

[0072] The display device can be applied to, for example, image capturing and displaying devices such as wearable devices such as smart glasses, head-mounted displays, and smart contact lenses. Such image capturing and displaying devices include, for example, an image capturing device capable of photoelectric conversion that converts visible light into an electrical signal, and a displaying device that emits visible light.

[0073] FIG. 6A is a schematic diagram showing an example of a wearable device. An imaging device 1602, such as a CMOS sensor or a SPAD sensor, is provided on the front side of a lens 1601 of smart glasses 1600 (glasses) shown in FIG. 6A. A CMOS (Complementary Metal-Oxide-Semiconductor) sensor is a solid-state imaging element using a complementary metal-oxide semiconductor. A SPAD (Single Photon Avalanche Diode) sensor is a sensor having an electronic element that outputs a large electrical pulse signal by multiplying a single photon incident on a pixel, like an avalanche. A display device is provided on the back side of the lens 1601. The smart glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the imaging device 1602 and the display device, and controls the operations of the imaging device 1602 and the display device. An optical system for focusing light on the imaging device 1602 is formed in the lens 1601.

[0074] FIG. 6B is a schematic diagram showing another example of a wearable device. Smart glasses 1610 (eyeglasses) shown in FIG. 6B include a control device 1612. The control device 1612 is equipped with an imaging device equivalent to the imaging device 1602 (FIG. 6A) and a display device. A lens 1611 is formed with an optical system for projecting light emitted from the imaging device and the display device within the control device 1612, thereby projecting an image. The control device 1612 functions as a power source for supplying power to the imaging device and the display device, and controls the operation of the imaging device and the display device. The control device may also include a gaze detection unit for detecting the wearer's gaze. Infrared light can be used for gaze detection. The infrared light emitting unit emits infrared light toward the eyeball of a user gazing at a displayed image. An imaging unit with a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining a captured image of the eyeball. By providing a reduction unit for reducing light from the infrared light emitting unit to the display unit in a planar view, degradation of image quality can be reduced.

[0075] The smart glasses 1610 detect the user's line of sight with respect to the displayed image from an image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using an image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used. Specifically, gaze detection processing based on the pupil-corneal reflex method is performed. Using the pupil-corneal reflex method, a gaze vector representing the direction (rotation angle) of the eyeball is calculated based on the image of the pupil and the Purkinje image contained in the image of the eyeball, thereby detecting the user's gaze.

[0076] The display device may have an imaging device with a light receiving element, and may control the display image of the display device based on user line-of-sight information from the imaging device. Specifically, a first field of view area where the user gazes and a second field of view area other than the first field of view area are determined based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0077] The display area includes a first display area and a second display area different from the first display area, and a high-priority area is determined from the first display area and the second display area based on line-of-sight information. The first and second viewing areas may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of areas other than the high-priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0078] Artificial intelligence (AI) may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to an object in the line of sight from the image of the eyeball, using as training data an image of the eyeball and the actual direction in which the eyeball in the image was looking. The AI ​​program may be provided in the display device, the imaging device, or an external device. If the AI ​​program is provided in the external device, information is transmitted to the display device via communication. When display control is based on visibility detection, it can be preferably applied to smart glasses that further include an imaging device that captures images of the outside. The smart glasses can display captured external information in real time.

[0079] As described above, a display device including the organic light-emitting element of the present invention can display information stably with good image quality for a long period of time. Furthermore, the highly efficient and bright light output can achieve both good visibility outdoors and power-saving display. [Example]

[0080] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples as long as the gist of the invention is not exceeded. The terms "parts" and "%" used to describe the amounts of components are based on mass unless otherwise specified.

[0081] <Method for measuring layer thickness (average thickness)> The film thickness was measured at five points, each ±25 mm away from the center of the substrate in the x and y directions, using a stylus step gauge (product name "P-16+", manufactured by KLA Tencor), and the average value of these five points was used as the film thickness (average film thickness) of each layer formed.

[0082] <Preparing ingredients> Materials (A-1) and (A-2) for the hole injection layer represented by the following formulas (A-1) and (A-2) and materials (B-1) and (B-2) for the hole transport layer represented by the following formulas (B-1) and (B-2) were prepared. Materials (C-1), (C-2), (D-1), and (D-2) for the light-emitting layer represented by the following formulas (C-1), (C-2), (D-1), and (D-2) were also prepared.

[0083] TIFF2026043501000005.tif52170

[0084] TIFF2026043501000006.tif129170

[0085] TIFF2026043501000007.tif116170

[0086] Furthermore, the following various materials were prepared. CT-1: Chlorotrifluoroethylene compound, trade name "Daifloil #20", manufactured by Daikin Industries, number average molecular weight 1,000, heavy oil-like substance, viscosity (25°C) 2,000 mPa·s CT-2: Chlorotrifluoroethylene compound, trade name "Daifloil #10", manufactured by Daikin Industries, number average molecular weight 900, heavy oil-like, viscosity (25°C) 350 mPa·s CT-3: Chlorotrifluoroethylene compound, trade name "Daifloil #3", manufactured by Daikin Industries, number average molecular weight 700, medium oily state, viscosity (25°C) 80 mPa·s CT-4: Chlorotrifluoroethylene compound, trade name "Daifloil #1", manufactured by Daikin Industries, number average molecular weight 500, light oil-like, viscosity (25°C) 15 mPa·s PCTFE: Polychlorotrifluoroethylene, Sigma-Aldrich, Catalog No. 454710, CAS No. 334-68-9 Alkyl fluoride-1: Fluorocyclohexane, manufactured by Tokyo Chemical Industry Co., Ltd. Alkyl fluoride-2:1-fluorodecane, from Sigma-Aldrich Palmitic acid ester: Product name "Exsepar IPP", manufactured by Kao

[0087] <Manufacturing of organic light-emitting devices> Example 1 A transparent conductive support substrate (ITO substrate) was obtained by forming an ITO film on a glass substrate by sputtering to form a 100 nm thick anode. A 10 nm thick hole injection layer was formed on the ITO substrate by vapor deposition (resistance heating vacuum deposition) using A-1, and then a 40 nm thick hole injection layer was formed on the hole injection layer by vapor deposition using B-1.

[0088] A liquid composition for the emissive layer was prepared by mixing 0.095 parts of C-1, 1.905 parts of D-1, 0.0004 parts of CT-1, 20 parts of methoxytoluene, and 80 parts of cyclohexylbenzene, followed by filtration through a 0.2 μm filter. The prepared liquid composition was applied to the hole injection layer by die coating and then dried to form an emissive layer with a thickness of 30 nm. The sample with the emissive layer formed was placed in a vacuum deposition machine, and an electron transport layer (TPBi) with an average thickness of 20 nm, an electron injection layer (LiF) with an average thickness of 0.5 nm, and a cathode (aluminum) with an average thickness of 100 nm were successively formed by vapor deposition. The opposing electrode areas were 3 mm 2 Next, in a dry air atmosphere, a protective glass plate was placed over the device, and the device was sealed with an acrylic resin adhesive to obtain an organic light-emitting device.

[0089] (Examples 2 to 10, Comparative Examples 1 to 8) An organic light-emitting layer element was obtained in the same manner as in Example 1, except that various materials shown in Tables 1, 2-1, and 2-2 (units: parts in the upper rows in Tables 2-1 and 2-2) were used and each layer was formed by the method shown in Tables 1, 2-1, and 2-2. The film thickness of each constituent layer constituting the obtained organic light-emitting element is shown in Tables 1, 2-1, and 2-2.

[0090] TIFF2026043501000008.tif175170

[0091] TIFF2026043501000009.tif131170

[0092] TIFF2026043501000010.tif157170

[0093] <Production of samples for evaluating film thickness uniformity> The glass substrate was washed and then subjected to a UV ozone treatment. The liquid compositions for forming the light-emitting layer used in producing the organic light-emitting devices of the above-described Examples and Comparative Examples were applied to the glass substrate after the UV ozone treatment by a die coating method, and then dried to form light-emitting layers, thereby obtaining samples for evaluating film thickness uniformity.

[0094] <Evaluation> The produced organic light-emitting devices were evaluated as follows. The evaluation results are shown in Tables 3 and 4.

[0095] (external quantum efficiency, lifetime) Current density 20mA / cm 2 The organic light-emitting device manufactured under the above conditions was continuously driven, and the external quantum efficiency and the time (lifetime) until the luminance degradation ratio reached 5% were measured. A relative evaluation was then performed, with the external quantum efficiency and lifespan of an organic light-emitting device in which an emitting layer was formed without using a trichlorofluoroethylene compound as the reference (100). The external quantum efficiency and luminance were measured using a spectroradiometer (product name "SR-LEDW", manufactured by Topcon Technohouse).

[0096] (film thickness uniformity) The thickness of the light-emitting layer was measured at five points on the fabricated film thickness uniformity evaluation sample (substrate), including the center point and points ±25 mm away from the center of the substrate in the x and y directions, using a stylus step profiler (product name "P-16+", manufactured by KLA Tencor). The difference between the maximum and minimum film thicknesses was calculated, and a relative evaluation was performed using the difference between the maximum and minimum film thicknesses of a light-emitting layer formed without using a trichlorofluoroethylene compound as the reference (100).

[0097] TIFF2026043501000011.tif101170

[0098] TIFF2026043501000012.tif88170

[0099] The disclosure of this embodiment includes the following configurations and methods. (Configuration 1) A liquid composition used to form constituent layers of an organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, the liquid composition comprising: A liquid composition comprising a compound having a number average molecular weight of 1,050 or less and a repeating structural unit represented by the following formula (1), and an organic solvent: TIFF2026043501000013.tif27170 (Configuration 2) The liquid composition according to Configuration 1, wherein the compound has a number average molecular weight of 400 or more and 700 or less. (Configuration 3) The liquid composition according to Configuration 1 or 2, wherein the viscosity of the compound at 25°C is 10 mPa·s or more and 30 mPa·s or less. (Configuration 4) The liquid composition according to any one of Configurations 1 to 3, wherein the content (mass %) of the compound is 0.01 mass % or less based on the total mass of components other than the organic solvent. (Method 1) A method for producing an organic light-emitting element having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, comprising the steps of: 5. A method for producing an organic light-emitting element, comprising: applying and drying the liquid composition according to any one of Configurations 1 to 4 to form at least one layer selected from the group consisting of the hole injection layer, the hole transport layer, and the light-emitting layer. (Configuration 5) An organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, An organic light-emitting device, wherein at least one layer selected from the group consisting of the hole injection layer, the hole transport layer, and the light-emitting layer contains a compound having a number average molecular weight of 1,050 or less and having a repeating structural unit represented by the following formula (1): TIFF2026043501000014.tif27170 (Configuration 6) A display device having a plurality of pixels, A display device, wherein at least one of the plurality of pixels comprises the organic light-emitting element according to configuration 5 and a transistor connected to the organic light-emitting element. [Explanation of symbols]

[0100] 1. Interlayer insulation layer 2 reflective electrode 3. Insulation layer 4. Organic semiconductor layer 5 Transparent electrode 6 Protective layer 7R, 7G, 7B color filters 10R, 10G, 10B subpixels 11 Circuit Board 18 Active Elements 21 Anode 22 Organic semiconductor layer 23 Cathode 26 Organic light-emitting devices

Claims

1. A liquid composition used for forming constituent layers of an organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, the liquid composition comprising: A liquid composition comprising a compound having a number average molecular weight of 1,050 or less and a repeating structural unit represented by the following formula (1), and an organic solvent:

2. 2. The liquid composition according to claim 1, wherein the compound has a number average molecular weight of 400 or more and 700 or less.

3. 2. The liquid composition according to claim 1, wherein the viscosity of the compound at 25°C is 10 mPa·s or more and 30 mPa·s or less.

4. The liquid composition according to claim 1 , wherein the content (% by mass) of the compound is 0.01% by mass or less based on the total mass of components other than the organic solvent.

5. A method for manufacturing an organic light-emitting element having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, comprising:

5. A method for manufacturing an organic light-emitting element, comprising: applying and drying the liquid composition according to claim 1 to form at least one layer selected from the group consisting of the hole injection layer, the hole transport layer, and the light-emitting layer.

6. An organic light-emitting device having a laminated structure in which constituent layers including a hole injection layer, a hole transport layer, and a light-emitting layer are laminated, an organic light-emitting element, wherein at least one layer selected from the group consisting of the hole injection layer, the hole transport layer, and the light-emitting layer contains a compound having a number average molecular weight of 1,050 or less and having a repeating structural unit represented by the following formula (1):

7. A display device comprising a plurality of pixels, A display device, wherein at least one of the plurality of pixels comprises the organic light-emitting element according to claim 6 and a transistor connected to the organic light-emitting element.

Images