Light-emitting element, display device, and manufacturing method for light-emitting element

Abstract

The present invention prevents a light-emitting layer from deteriorating due to moisture permeating a sealant and penetrating in minute amounts. A light-emitting element (100) comprises a charge transport layer (30) and a charge transport layer (60) laminated on a substrate (10) between an electrode (20) and an electrode (70), a light-emitting layer (50) laminated between the charge transport layer (30) and the charge transport layer (60), and a water soluble resin layer (40) provided so as to be in contact with the light-emitting layer (50), said water soluble resin layer including a water soluble resin.

Description

Light-emitting element, display device, and method for manufacturing light-emitting element

[0001] The present disclosure relates to a light-emitting element, a display device, and a method for manufacturing a light-emitting element.

[0002] In recent years, various display devices equipped with light-emitting elements have been developed, and in particular, display devices equipped with QLEDs (Quantum dot Light Emitting Diodes) or OLEDs (Organic Light Emitting Diodes) have attracted considerable attention because of their ability to achieve low power consumption, thinness, and high image quality.

[0003] For example, Patent Document 1 describes an organic electroluminescence element comprising an organic functional layer sandwiched between a pair of electrodes, the organic functional layer including a liquid phase forming layer formed by a liquid phase method, and the liquid phase forming layer being formed on an intermediate layer having a surface modification function.

[0004] Japanese Patent Publication No. 2005-235569

[0005] However, even with the above-described conventional technology, even if the light emitting element is sealed, there is a problem in that the light emitting layer deteriorates due to moisture (also called humidity) that penetrates from the outside of the light emitting element.

[0006] In other words, the present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a novel light-emitting element and related technologies that can reduce the possibility of deterioration of the light-emitting layer due to the penetration of moisture.

[0007] A light-emitting element according to one aspect of the present disclosure comprises first and second electrodes, a plurality of charge transport layers stacked between the first and second electrodes, a light-emitting layer stacked between the plurality of charge transport layers, and at least one water-soluble resin layer arranged to contact at least one surface selected from the front surface, back surface, and outer peripheral end surface of the light-emitting layer, wherein the water-soluble resin layer contains a water-soluble resin.

[0008] A display device according to one aspect of the present disclosure is a display device comprising a substrate and a plurality of light-emitting elements on the substrate, each of the plurality of light-emitting elements comprising first and second electrodes, a plurality of charge transport layers stacked between the first and second electrodes, a light-emitting layer stacked between the plurality of charge transport layers, and at least one water-soluble resin layer arranged to contact at least one surface selected from the front surface, back surface, and outer peripheral end surface of the light-emitting layer, and the water-soluble resin layer contains a water-soluble resin.

[0009] Furthermore, a method for manufacturing a light-emitting element according to one aspect of the present disclosure is a method for manufacturing a light-emitting element comprising: a light-emitting layer; and at least one water-soluble resin layer provided in contact with the light-emitting layer; wherein a composition for forming the water-soluble resin layer contains a water-soluble resin and a positive photosensitive agent; and the method includes the steps of: applying the composition to a substrate; exposing a portion of the applied composition to light to develop a pattern in the water-soluble resin layer; forming the light-emitting layer in contact with the pattern; and peeling and developing the light-emitting layer on the pattern by peeling off at least a portion of the water-soluble resin layer other than the pattern.

[0010] According to the present disclosure, it is possible to provide a novel light-emitting element and related techniques that can reduce the possibility of deterioration of the light-emitting layer due to the intrusion of moisture.

[0011] 1 is a cross-sectional view showing a schematic configuration of a light-emitting element 100 according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing a schematic configuration of a light-emitting element 101 according to a modified example of the present disclosure. FIG. 3 is a cross-sectional view showing a schematic configuration of a light-emitting element 102 according to a modified example of the present disclosure. FIG. 4 is a cross-sectional view showing a schematic configuration of a light-emitting element 103 according to a modified example of the present disclosure. FIG. 5 is a cross-sectional view showing a schematic configuration of a light-emitting element 104 according to a modified example of the present disclosure. FIG. 6 is a cross-sectional view showing a schematic configuration of a light-emitting element 105 according to a modified example of the present disclosure. FIG. 7 is a plan view showing a schematic configuration of a display device 200 according to an embodiment of the present disclosure. FIG. 8 is a cross-sectional view showing a schematic configuration of a display device 200 according to an embodiment of the present disclosure. FIG. 9 is a cross-sectional view showing a schematic configuration of a display device 210 according to a modified example of the present disclosure. FIG. 10 is a cross-sectional view showing a schematic configuration of a display device 220 according to a modified example of the present disclosure. FIG. 11 is a cross-sectional view showing an outline of steps from a step of forming a water-soluble resin layer 43A to a step of exposing the water-soluble resin layer 43A, which are included in the developing step, included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 12 is a cross-sectional view showing an outline of a step of developing a pattern on the exposed water-soluble resin layer 43A, included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 1 is a cross-sectional view showing an outline of a step of peeling and developing a first light-emitting layer 53B, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 1 is a cross-sectional view showing an outline of adjusting a thickness t1 of a water-soluble resin layer 43A in the peel-and-develop step of the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing an outline of a step of forming a water-soluble resin layer 43B (a step of forming a second water-soluble resin layer), which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional view showing an outline of a step (second time) up to exposing the water-soluble resin layer 43B, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing an outline of a step (second developing step) of developing a pattern in the water-soluble resin layer 43B, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure.1 is a cross-sectional view showing an outline of a process of peeling and developing a second light-emitting layer 53R (a second peel-and-develop process), which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 1 is a cross-sectional view showing an outline of processes from a process of forming a water-soluble resin layer 43C (a third water-soluble resin layer forming process) to exposing the water-soluble resin layer 43C, which are included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing an outline of a process of developing a pattern in a water-soluble resin layer 43C (a third developing process), which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional view showing an outline of a process of forming a third light-emitting layer 53G (a third light-emitting layer forming process), which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing an outline of a display device 230 manufactured by the method for manufacturing a light-emitting element according to an embodiment of the present disclosure.

[0012] <Light Emitting Element> First, the configuration of a light emitting element 100 including a quantum dot light emitting diode (QLED) according to an embodiment of the present disclosure will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view showing a schematic configuration of the light emitting element 100 according to this embodiment.

[0013] In this specification, each layer in each cross-sectional view is described with the upper surface being the front surface (first surface), the lower surface being the back surface (second surface), and the surfaces at both ends being the outer peripheral end surfaces (third surfaces).

[0014] 1 , in the light-emitting element 100 of the present embodiment, a first charge transport layer 30 serving as a hole transport layer, a water-soluble resin layer 40, a light-emitting layer 50, and a second charge transport layer 60 serving as an electron transport layer are stacked in this order between a first electrode 20 serving as an anode and a second electrode 70 serving as a cathode provided on a substrate 10, and the water-soluble resin layer 40 is provided so as to be in contact with the back surface of the light-emitting layer 50. The layer stacked between the first and second electrodes is sometimes referred to as a functional layer, and this functional layer is a layer including a plurality of charge transport layers, a light-emitting layer stacked between the plurality of charge transport layers, and a water-soluble resin layer in contact with the light-emitting layer.

[0015] The light emitting element 100 constitutes a light emitting region of a display area of ​​the display device on the substrate 10, and is surrounded by a non-light emitting region on the substrate 10 that does not emit light.

[0016] The light-emitting element 100 shown in FIG. 1 may be a top-emission type or a bottom-emission type. In the light-emitting element 100, the second electrode 70 serving as a cathode is disposed in a layer above the first electrode 20 serving as an anode, the first electrode 20 serving as an anode is formed from an electrode material that reflects visible light, and the second electrode 70 serving as a cathode is formed from an electrode material that transmits visible light. To make the light-emitting element 100 a bottom-emission type, the second electrode 70 serving as a cathode is disposed in a layer above the first electrode 20 serving as an anode, the first electrode 20 serving as an anode is formed from an electrode material that transmits visible light, and the second electrode 70 serving as a cathode is formed from an electrode material that reflects visible light.

[0017] The electrode material that reflects visible light is not particularly limited as long as it can reflect visible light and has conductivity, and examples thereof include metal materials such as Al, Cu, Au, Mg, Li, and Ag, alloys of the above metal materials, laminates of the above metal materials and transparent metal oxides (e.g., indium tin oxide, indium zinc oxide, indium gallium zinc oxide, etc.), and laminates of the above alloys and the above transparent metal oxides.

[0018] On the other hand, the electrode material that transmits visible light is not particularly limited as long as it can transmit visible light and has conductivity, and examples thereof include transparent metal oxides (e.g., indium tin oxide, indium zinc oxide, indium gallium zinc oxide, etc.), thin films made of metal materials such as Al and Ag, and nanowires made of metal materials such as Al and Ag.

[0019] In one embodiment, the light-emitting element may have a forward stack structure as shown in Fig. 1, but is not limited to this and may have an inverted stack structure. Although not shown, a light-emitting element having an inverted stack structure can be constructed by laminating, in order from the first electrode side which is a cathode, a first charge transport layer which is an electron transport layer, a water-soluble resin layer, a light-emitting layer, a second charge transport layer which is a hole transport layer, and a second electrode which is an anode.

[0020] [First Charge Transport Layer] The light-emitting element 100 includes a first charge transport layer 30 between the first electrode 20 and the light-emitting layer 50. The first charge transport layer 30, which is a hole transport layer, transports holes from the first electrode 20 side, which is the anode, through the water-soluble resin layer 40 toward the light-emitting layer 50.

[0021] Although not shown, the first charge transport layer 30 may be composed of a plurality of layers from the viewpoint of increasing the hole injection efficiency. When the first charge transport layer 30 includes a plurality of hole transport layers, one of the hole transport layers may be referred to as a hole injection layer. When the first charge transport layer includes a hole injection layer, the first charge transport layer may have a hole injection layer formed on the first electrode, which is the anode, and a hole transport layer may be formed on the hole injection layer.

[0022] (Hole Injection Layer) The first charge transport layer 30 may be a hole injection layer that injects holes. The hole injection layer is also a layer that transports holes from the first electrode 20 side through the water-soluble resin layer 40 toward the light-emitting layer 50, and therefore may be one embodiment of a hole transport layer. Examples of hole injection materials contained in the hole injection layer include NiO, CuI, Cu ２ O, CoO, Cr ２ O ３ , CuAlS ２ The nanoparticles that are hole-injecting materials may have thiol, amine, or the like as ligands.

[0023] (Hole Transport Layer) The first charge transport layer 30 may be a hole transport layer that transports holes. The hole transport layer is a layer that transports holes from the first electrode 20 side, which is the anode, toward the light-emitting layer 50. The hole transport layer may be formed on the first electrode 20, which is the anode, or on the hole injection layer.

[0024] The material used for the hole transport layer is not particularly limited as long as it is a hole transport material that can stabilize the transport of holes to the light-emitting layer 50. The hole transport material in the hole transport layer preferably has high hole mobility. Furthermore, the hole transport material is preferably a material (electron blocking material) that can prevent electrons that have migrated from the second electrode 70, which is the cathode, from passing through. This is because the recombination efficiency of holes and electrons in the light-emitting layer 50 can be increased. The hole transport material is preferably a photosensitive hole transport material having a cationically polymerizable functional group such as an oxetane ring. Examples of the photosensitive hole transport material include N,N'-(4,4'-(cyclohexane-1,1-diyl)bis(4,1-phenylene))bis(N-(4-(6-(2-ethyloxetan-2-yloxy)hexyl)phenyl)-3,4,5-trifluoroaniline), N4,N4'-bis(4-(6-((3-ethyloxetan-3-yl)methoxy)hexyloxyphenyl)-N4,N4'-bis(4-methoxyphenyl)biphenyl-4,4'-diamine, ... Examples of the hole transport material include (oxetan-3-yl)methoxy)hexyl)phenyl)-N4,N4'-diphenylbiphenyl-4,4'-diamine. The photosensitive hole transport material contained in the hole transport layer may be cationic polymerized with, for example, a photoacid generator. The hole transport layer may also contain a product generated by exposure of the photoacid generator. Other examples of the hole transport material include poly-TPD, polyvinylcarbazole (PVK), and poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl))diphenylamine)] (TFB).

[0025] [Water-Soluble Resin Layer] The water-soluble resin layer 40 is a layer that protects the light-emitting layer 50 from moisture that penetrates into the light-emitting element 100 from the outside of the display device. In the light-emitting element 100 according to one embodiment, the water-soluble resin layer 40 is in close contact with the surface of the first charge transport layer 30 and also with the back surface of the light-emitting layer 50, thereby preventing moisture from penetrating into the light-emitting layer 50 from the first charge transport layer 30 side. In addition, the back surface of the water-soluble resin layer 40 is in contact with the entire surface of the first charge transport layer 30, which is a hole transport layer. As a result, in the light-emitting element 100, the light-emitting layer 50 and the first charge transport layer 30 are not in direct contact with each other.

[0026] As will be described later, the water-soluble resin layer 40 is a layer formed from a composition containing a water-soluble resin and a positive photosensitive agent.

[0027] The water-soluble resin is a water-soluble thermoplastic resin that dissolves in pure water and alkaline aqueous solution. From the viewpoint of preventing the re-release of captured moisture, a water-soluble resin that is more hydrophilic than amphipathic molecules is preferred. The water-soluble resin contains monomer units derived from different hydrophilic monomers, and its water solubility can be determined as the solubility parameter (SP value) of the water-soluble resin. The SP value of the water-soluble resin can be roughly calculated by referring to the SP value of the monomer constituting the monomer unit contained in the water-soluble resin or the SP value of the homopolymer.

[0028] Here, the SP value of the water-soluble resin can be divided into three terms as shown in the following formula (1): δ (solubility parameter) = (δ Ｄ ２ +δ Ｐ ２ +δ Ｈ ２ ) １／２ ...(1) (In formula (1), δ Ｄ is the dispersion term, δ Ｐ is the polar term, δ Ｈ is the hydrogen bond term.) The water-soluble resin is characterized by the polar term δ among the parameters shown in formula (1). ＰThe polarity term δ is preferably 5.0 or more from the viewpoint of increasing the solubility of the water-soluble resin layer in an organic solvent developer and increasing the resistance to dissolution in an alkaline developer. Ｐ can be obtained from, for example, Hansen Solubility Parameter Estimation Software, and the polarity term δ of the monomer constituting the water-soluble resin Ｐ and the molar ratio of the monomer units contained in the water-soluble resin.

[0029] The water-soluble resin has good compatibility with the hole injection material, hole transport material, and the light-emitting material described below. This improves the adhesion between the first charge transport layer 30 and the water-soluble resin layer 40, and also improves the adhesion between the water-soluble resin layer 40 and the light-emitting layer 50. This effectively prevents moisture from penetrating between the first charge transport layer 30 and the light-emitting layer 50 from the outside.

[0030] The water-soluble resin is preferably a block copolymer or a graft copolymer containing two or more polymer units derived from different hydrophilic monomers, more preferably a graft copolymer. Here, each of the polymer units may be a homopolymer or copolymer of monomer units derived from a water-soluble monomer. When the water-soluble resin is a block copolymer or a graft copolymer containing two or more polymer units, the film-forming properties of the water-soluble resin can be suitably controlled by the difference in water solubility of each polymer unit.

[0031] The type of monomer unit constituting the polymer unit contained in the water-soluble resin may be selected based on the water solubility of the homopolymer of each monomer unit. The water solubility of the homopolymer of each monomer unit may be roughly calculated by referring to the SP value of the homopolymer or the SP value of the monomer. When the water-soluble resin is a block copolymer or a graft copolymer, the polymer unit with relatively low water solubility may be referred to as the first polymer unit, and the polymer unit with relatively high water solubility may be referred to as the second polymer unit. It is preferable that the difference (SP value difference) between the water solubility of the first polymer unit and the water solubility of the second polymer unit is large.

[0032] Examples of the monomer constituting the first polymer unit include monomers having an SP value in the range of 9.0 to 15.0, such as (meth)acrylic acid (SP: 9.6), (meth)acrylamide (9.0 to 15.0), N-vinylacetamide (SP value: 10.9), polyvinyl alcohol (SP value: 12.6), ethylene glycol (SP value: 14.2), and ethylenediamine (SP value: 12.4). The SP value of polyvinyl alcohol can be determined as the SP value of a vinyl alcohol homopolymer. When the monomer is (meth)acrylic acid, the (meth)acrylic acid may be contained in the first polymer unit as an alkali metal salt or an ammonium salt. Examples of the monomer units derived from these monomers include vinyl alcohol monomer units, (meth)acrylic acid-derived monomer units, (meth)acrylate-derived monomer units, (meth)acrylamide-derived monomer units, and N-vinylacetamide-derived monomer units, with vinyl alcohol monomer units being preferred. Other examples of the monomer units include ethylene oxide units, ethyleneamine units, and propyleneamine units. The water-soluble monomer units constituting the first polymer units may be, for example, monomer units derived from monomers having a hydrophilic group such as a carboxyl group, a hydroxyl group, an amino group, or an amide group, or may be monomer units that, upon polymerization, form a hydrophilic main chain, exemplified by polyether chains such as polyethylene glycol, and polyamine chains such as spermine and spermidine.

[0033] The monomer constituting the second polymer unit preferably has an SP value of greater than 15.0, more preferably greater than or equal to 20.0. An example of the monomer constituting the second polymer unit is vinylpyrrolidone (SP value: 26.2).

[0034] In this specification, "(meth)acrylic acid" includes both "acrylic acid" and "methacrylic acid", and "(meth)acrylamide" includes both "acrylamide" and "methacrylamide".

[0035] The first polymer unit contained in the block copolymer or the graft copolymer may be, for example, a homopolymer unit of a monomer unit derived from vinyl alcohol (i.e., a vinyl alcohol monomer unit), and the second polymer unit may be, for example, a homopolymer unit of a monomer unit derived from N-vinylpyrrolidone (i.e., an N-vinylpyrrolidone monomer unit).

[0036] The water solubility of the polymer unit obtained by polymerizing the vinyl alcohol monomer unit, i.e., the vinyl alcohol polymer unit, may be adjusted by substituting some of the hydrogen atoms in the hydroxyl groups with hydrophobic groups, such as epoxy groups and (meth)acryloyl groups.

[0037] The water-soluble resin may be designed by adjusting the ratio of the first polymer unit to the second polymer unit contained in the block copolymer or graft copolymer. More specifically, for example, the film-forming characteristics of the water-soluble resin can be controlled by adjusting the molar ratio of the monomer unit contained in the first polymer unit, assuming that the sum of the molar amounts of the monomer units contained in the first polymer unit and the second polymer unit is 1.0. Furthermore, for example, the larger the molar ratio of the monomer unit contained in the first polymer unit, the more the first polymer unit can be oriented on the surface of the water-soluble resin layer 40, i.e., the surface facing the back surface of the light-emitting layer 50. This allows the interface between the surface of the water-soluble resin layer 40 and the back surface of the light-emitting layer 50 to be uniform, suppressing charge concentration at the interface and improving the reliability of the light-emitting device.

[0038] For example, when vinyl alcohol polymer units are used as the first polymer units, the ratio of the first polymer units contained in the water-soluble resin is referred to as the PVA (polyvinyl alcohol) ratio.

[0039] For example, when a block copolymer or graft copolymer contains, as the first polymer unit, a homopolymer unit of a monomer unit derived from vinyl alcohol, and as the second polymer unit, a homopolymer unit of a monomer unit derived from N-vinylpyrrolidone, the PVA ratio, which is the ratio of the first polymer unit, is preferably 0.3 to 0.9. A PVA ratio greater than 0.3 can prevent excessive removal of the water-soluble resin when forming a water-soluble resin layer using, for example, an alkaline aqueous solution. Furthermore, a PVA ratio less than 0.9 can prevent excessive residue of the water-soluble resin. The ratio of the first polymer unit to the second polymer unit in the block copolymer or graft copolymer may be adjusted in accordance with a PVA ratio value of 0.3 to 0.9.

[0040] The water-soluble resin is preferably a block copolymer or a graft copolymer, but is not limited to these, and may be a homopolymer of a monomer unit derived from a water-soluble monomer, or a copolymer containing monomer units derived from two or more types of water-soluble monomers.

[0041] The positive photosensitizer contained in the water-soluble resin layer 40 is typically a diazoquinone compound. In the water-soluble resin layer 40, the positive photosensitizer may be contained as the diazoquinone compound itself or as a product generated from the diazoquinone compound upon exposure.

[0042] In the light-emitting element 100, the thickness t1 of the water-soluble resin layer 40 located between the surface of the first charge transport layer 30 and the back surface of the light-emitting layer 50 is preferably 20 μm or less. When the thickness t1 of the water-soluble resin layer 40 is 20 μm or less, holes transported from the first charge transport layer 30, which is a hole transport layer, can be suitably moved to the light-emitting layer 50, thereby improving the carrier balance between the first charge transport layer 30 and the second charge transport layer 60 in the light-emitting element 100. Furthermore, when the thickness t1 of the water-soluble resin layer 40 is 5 nm or more, moisture can be prevented from penetrating into the light-emitting layer 50 from the side of the first charge transport layer 30, which is a hole transport layer.

[0043] [Light-Emitting Layer] The light-emitting layer 50 emits light by recombination of holes transported from the first electrode 20, which is an anode, and electrons transported from the second electrode 70, which is a cathode. In this embodiment, the light-emitting layer 50 is a quantum dot light-emitting layer including quantum dots (QDs: semiconductor nanoparticles) of each color as the light-emitting material, but is not limited thereto and may be an OLED (organic light-emitting diode).

[0044] The light-emitting layer 50 can emit any of red light, green light, and blue light. Here, red light refers to light having a central emission wavelength in a wavelength band of more than 600 nm and not more than 780 nm. Green light refers to light having a central emission wavelength in a wavelength band of more than 500 nm and not more than 600 nm. Furthermore, blue light refers to light having a central emission wavelength in a wavelength band of 400 nm or more and not more than 500 nm. In one embodiment, the multiple types of quantum dots are a combination of red quantum dots, green quantum dots, and blue quantum dots, but this combination is not necessarily required.

[0045] The light-emitting layer 50 may include, for example, a continuous film of a metal sulfide and a plurality of quantum dots encapsulated in the continuous film. Examples of the metal sulfide include zinc sulfide (ZnS), ZnTeS, and ZnMgS. ２ , MgS, Ga ２ S ３ , ZnGa ２ S ４ , MgGa ２ S ４ The continuous film may be, for example, a sulfide semiconductor having a thickness of 1000 nm in a plane perpendicular to the film thickness direction at any position in the film thickness direction of the light emitting layer 50. ２ The light-emitting layer 50 may have an area of ​​100 nm or more and 100 nm or less in average thickness, and the maximum thickness of the light-emitting layer 50 may be no more than twice the minimum thickness.

[0046] The quantum dots (QDs) included in the light-emitting layer 50 may have, for example, a core structure, a core / shell structure, a core / shell / shell structure, or a shell structure with a continuously varying core / shell ratio. When the quantum dots (QDs) have a core structure, a ligand is provided on the surface of the core. When the quantum dots (QDs) have a shell structure, a ligand is provided on the surface of the shell. The core portion of the quantum dot (QD) may be composed of, for example, Si, C, etc., if it is a unicomponent system, for example, CdSe, CdS, CdTe, InP, GaP, InN, ZnSe, ZnS, ZnTe, etc., if it is a ternary system, for example, CdSeTe, GaInP, ZnSeTe, etc., or if it is a quaternary system, for example, AIGS, etc. In the case of a binary system, the shell portion can be composed of, for example, CdS, CdTe, CdSe, ZnS, ZnSe, ZnTe, etc., and in the case of a ternary system, the shell portion can be composed of, for example, CdSSe, CdTeSe, CdSTe, ZnSSe, ZnSTe, ZnTeSe, AIP, etc.

[0047] The quantum dot (QD) refers to a dot having a maximum width of 100 nm or less. The shape of the quantum dot (QD) is not particularly limited as long as it satisfies the above maximum width, and is not limited to a spherical three-dimensional shape (circular cross-sectional shape). For example, it may have a polygonal cross-sectional shape, a rod-like three-dimensional shape, a branch-like three-dimensional shape, a three-dimensional shape with an uneven surface, or a combination thereof.

[0048] The ligand included in the quantum dots (QDs) may be an inorganic ligand or an organic ligand. When the ligand included in the quantum dots (QDs) is an organic ligand, the organic ligand may be an organic compound having a functional group such as an amine or a thiol. The quantum dots (QDs) may include the inorganic ligand described above and may also include an organic ligand. Furthermore, when the ligand included in the quantum dots (QDs) is an inorganic ligand, it may be, for example, a halogen ligand containing a halogen atom. In this case, the average concentration of halogen atoms within 1 nm from the outermost surface of each quantum dot (QD) may be 10% higher, 50% higher, or 100% higher than the average concentration of halogen atoms at other positions.

[0049] [Second Charge Transport Layer] The light-emitting element 100 includes a second charge transport layer 60 between the second electrode 70 and the light-emitting layer 50. When the second electrode 70 is a cathode, the second charge transport layer 60 is an electron transport layer. The second charge transport layer 60, which is an electron transport layer, transports electrons from the second electrode 70, which is a cathode, toward the light-emitting layer 50. Although not shown, the second charge transport layer may be composed of multiple layers.

[0050] The material used for the electron transport layer is not particularly limited as long as it is an electron transport material that can stabilize the transport of electrons to the light emitting layer 50. Examples of electron transport materials include ZnO, ZnS, ZrO, MgZnO, AlZnO, and TiO. ２ These nanoparticles may have ligands, such as organic ligands and inorganic ligands, on their surfaces.

[0051] [Light-emitting element 101 according to one modified example] The light-emitting element according to one embodiment of the present disclosure is not limited to the above embodiment. Fig. 2 is a cross-sectional view showing a schematic configuration of a light-emitting element 101 according to one modified example of the present disclosure. The same components as those in the light-emitting element 100 are assigned the same numbers, and their description will be omitted.

[0052] The light-emitting element 101 includes a first water-soluble resin layer (first water-soluble resin layer) 40 that contacts the back surface of the light-emitting layer 50, and a second water-soluble resin layer (second water-soluble resin layer) 40A that contacts the front surface of the light-emitting layer 50. The water-soluble resin layer 40 and the water-soluble resin layer 40A are in close contact with the front and back surfaces of the light-emitting layer 50, respectively, thereby preventing moisture from penetrating into the light-emitting layer 50.

[0053] The first water-soluble resin layer refers to a water-soluble resin layer in contact with the back surface of the light-emitting layer, and the second water-soluble resin layer refers to a water-soluble resin layer in contact with the front surface of the light-emitting layer. Either or both of the first and second water-soluble resin layers may be in contact with the outer peripheral end surface of the light-emitting layer. The water-soluble resin layer in contact with only the outer peripheral end surface of the light-emitting layer is referred to as a third water-soluble resin layer and is distinguished from the first and second water-soluble resin layers.

[0054] Furthermore, when one water-soluble resin layer that is continuous with each other is formed in multiple light-emitting elements, the water-soluble resin layer can be formed as a first water-soluble resin layer that contacts the back surface of the light-emitting layer of one light-emitting element (first light-emitting element), and as a second water-soluble resin layer that contacts the front surface of the light-emitting layer of another light-emitting element (second light-emitting element).

[0055] The water-soluble resin contained in the water-soluble resin layer 40A may be a water-soluble resin having the same composition as the water-soluble resin contained in the above-described water-soluble resin layer 40, or may be a water-soluble resin having a different composition. The water-soluble resin layer 40A is a layer containing at least a water-soluble resin, and may also contain a positive-type photosensitizer. The water-soluble resin layer 40A may be a layer formed of a water-soluble resin composition containing a water-soluble resin and a positive-type photosensitizer.

[0056] The water-soluble resin contained in the water-soluble resin layer 40A may be selected depending on the material of the light-emitting layer 50 that contacts the back surface of the water-soluble resin layer 40A. The mass average molecular weight of the water-soluble resin contained in the water-soluble resin layer 40A is preferably larger than the mass average molecular weight of the water-soluble resin contained in the water-soluble resin layer 40. When the mass average molecular weight of the water-soluble resin contained in the water-soluble resin layer 40A is larger than the mass average molecular weight of the water-soluble resin contained in the water-soluble resin layer 40, the light-emitting layer 50 can be protected.

[0057] The thickness of the water-soluble resin layer 40A between the surface of the light-emitting layer 50 and the back surface of the second charge transport layer 60, which is an electron transport layer, is preferably in the range of 5 to 50 nm. As a result, when an excess of carriers are injected from the second charge transport layer 60 into the light-emitting layer 50, the excess carriers are blocked by the water-soluble resin layer 40A, improving the carrier balance in the light-emitting layer 50 and improving the luminous efficiency.

[0058] [Light-emitting element 102 according to one modification] The light-emitting element according to one embodiment of the present disclosure is not limited to the above-described embodiment and modification. Fig. 3 is a cross-sectional view showing a schematic configuration of a light-emitting element 102 according to one modification of the present disclosure.

[0059] The light-emitting element 102 includes a first water-soluble resin layer 40 (first water-soluble resin layer) that contacts the back surface of the light-emitting layer 50A, and a second water-soluble resin layer (second water-soluble resin layer) 40B that contacts the front surface of the light-emitting layer 50A. The water-soluble resin layer 40B surrounds the outer peripheral edge surface of the light-emitting layer 50A and contacts the outer peripheral edge surface. In the light-emitting element 102, all surfaces of the light-emitting layer 50A, including the front, back, and outer peripheral edge surface, are covered with the water-soluble resin layer 40 and the water-soluble resin layer 40B, thereby preventing moisture from penetrating. Furthermore, in the light-emitting element 102, the back surface of the water-soluble resin layer 40 contacts the surface of the first charge transport layer 30, which is a hole transport layer, so that the light-emitting layer 50A and the first charge transport layer 30 are not in direct contact.

[0060] The water-soluble resin contained in the water-soluble resin layer 40B may be selected according to the type of light-emitting material contained in the light-emitting layer 50A, just like the water-soluble resin layer 40A.

[0061] [Light-emitting element 103 according to one modification] The light-emitting element according to one embodiment of the present disclosure is not limited to the above-described embodiment and modification. Fig. 4 is a cross-sectional view showing a schematic configuration of a light-emitting element 103 according to one modification of the present disclosure.

[0062] In the light-emitting element 103, the back surface of the light-emitting layer 50A is in contact with the surface of the water-soluble resin layer (first water-soluble resin layer) 40C, and the back surface of the second charge transport layer 60A is in contact with the surface of the light-emitting layer 50A. The water-soluble resin layer 40C and the second charge transport layer 60A are in contact with the outer peripheral end surface of the light-emitting layer 50A while surrounding the outer peripheral end surface of the light-emitting layer 50A. In the light-emitting element 103, an area on the surface of the water-soluble resin layer 40C that is not in contact with the light-emitting layer 50A and an area on the back surface of the second charge transport layer 60A that is not in contact with the light-emitting layer 50A are in close contact with each other. In the light-emitting element 103, the water-soluble resin layer 40C and the second charge transport layer 60A prevent moisture from penetrating into the light-emitting layer 50A.

[0063] In the light-emitting element 103, the thickness of the water-soluble resin layer 40C between the surface of the first charge transport layer 30 and the back surface of the light-emitting layer 50A can be designed to be the same as the thickness t1 of the water-soluble resin layer 40. Furthermore, the water-soluble resin layer 40C is thicker in the region not in contact with the light-emitting layer 50A than in the region in contact with the light-emitting layer 50A. In the light-emitting element 103, the water-soluble resin layer 40C prevents moisture from penetrating from the side surfaces of the light-emitting layer 50A.

[0064] The back surface of the water-soluble resin layer 40C included in the light-emitting element 103 is in contact with the entire surface of the first charge transport layer 30, which is a hole transport layer. As a result, in the light-emitting element 103, the light-emitting layer 50A and the first charge transport layer 30 are not in direct contact with each other.

[0065] [Light-emitting element 104 according to one modification] The light-emitting element according to one embodiment of the present disclosure is not limited to the above-described embodiment and modification. Fig. 5 is a cross-sectional view showing a schematic configuration of a light-emitting element 104 according to one modification of the present disclosure.

[0066] In a light-emitting element 104 according to one modification, the second charge transport layer 60B surrounds and contacts the outer peripheral end face of the light-emitting layer 50A, and a partial region of the surface of the water-soluble resin layer (first water-soluble resin layer) 40D contacts the back surface of the light-emitting layer 50A. The surface of the water-soluble resin layer 40D has a region that contacts the back surface of the light-emitting layer 50A and a region that does not contact the back surface of the light-emitting layer 50A, and the region that does not contact the back surface of the light-emitting layer 50A contacts the back surface of the second charge transport layer 60B, which is an electron transport layer. In the light-emitting element 104, the water-soluble resin layer 40D is in close contact with the first charge transport layer 30, and the region that does not contact the back surface of the light-emitting layer 50A is in close contact with the back surface of the second charge transport layer 60, thereby preventing moisture from penetrating through the interface between the first charge transport layer 30 and the second charge transport layer 60B.

[0067] The water-soluble resin layer 40D included in the light-emitting element 104 may have a thickness between the surface of the first charge transport layer 30 and the back surface of the light-emitting layer 50A that is the same as the thickness t1 of the water-soluble resin layer 40 included in the light-emitting element 100. However, the thickness of the water-soluble resin layer 40D in the region not in contact with the light-emitting layer 50A, that is, between the surface of the first charge transport layer 30 and the surface of the second charge transport layer 60, may be thinner than the thickness t1.

[0068] [Light-emitting element 105 according to one modification] The light-emitting element according to one embodiment of the present disclosure is not limited to the above-described embodiment and modification. Fig. 6 is a cross-sectional view showing a schematic configuration of a light-emitting element 105 according to one modification of the present disclosure.

[0069] 6, in the light-emitting element 105, the water-soluble resin layer (third water-soluble resin layer) 40E is in close contact with the outer peripheral end surface of the light-emitting layer 50A, and is also in close contact with the surface of the first charge transport layer 30 and the back surface of the second charge transport layer 60C. This prevents moisture from penetrating into the light-emitting layer 50A from the interface between the surface of the first charge transport layer 30 and the back surface of the second charge transport layer 60C.

[0070] In the light-emitting element 105, the surface of the first charge transport layer 30 is in contact with the back surface of the light-emitting layer 50A, and the surface of the light-emitting layer 50A is in contact with the back surface of the second charge transport layer 60C. This allows the light-emitting element 105 to set the drive voltage applied between the first electrode 20, which is the anode, and the second electrode 70, which is the cathode, regardless of the thickness of the water-soluble resin layer 40E.

[0071] <Display Device> FIG. 7 is a plan view showing a schematic configuration of the display device 200. As shown in FIG.

[0072] 7 , the display device 200 includes a frame area NDA and a display area DA. The display area DA of the display device 200 includes a plurality of single pixels PIX, each of which includes a red subpixel RSP, a blue subpixel BSP, and a green subpixel GSP. In this embodiment, a case where one pixel PIX is configured with a red subpixel RSP, a blue subpixel BSP, and a green subpixel GSP will be described as an example, but the present invention is not limited to this. For example, one pixel PIX may also include subpixels of other colors.

[0073] 8 , display device 200 has red subpixel RSP, blue subpixel BSP, and green subpixel GSP as light-emitting regions in a display area DA, where red subpixel RSP has a light-emitting element 110R that emits red light, blue subpixel BSP has a light-emitting element 110B that emits blue light, and green subpixel GSP has a light-emitting element 110G that emits green light. Display area DA of display device 200 has banks 140 surrounding each subpixel as a non-light-emitting region.

[0074] The light-emitting element 110R includes a functional layer 90R having a red-emitting light-emitting layer between the first electrode 20 and the second electrode 70. The light-emitting element 110B includes a functional layer 90B having a blue-emitting light-emitting layer between the first electrode 20 and the second electrode 70. The light-emitting element 110G includes a functional layer 90G having a green-emitting light-emitting layer between the first electrode 20 and the second electrode 70. In each of the functional layers 90R, 90B, and 90G, a first charge transport layer, a light-emitting layer, a second charge transport layer, and at least one water-soluble resin layer are stacked between the first electrode 20 and the second electrode 70, as illustrated in FIGS. 1 to 6 , and the water-soluble resin layer is in contact with at least a portion of the light-emitting layer.

[0075] In the present embodiment, the light-emitting element 110R emitting red light, the light-emitting element 110B emitting blue light, and the light-emitting element 110G emitting green light are described as quantum dot light-emitting diodes (QLEDs) as an example, but the present invention is not limited to this. The light-emitting element 110R, the light-emitting element 110B, and the light-emitting element 110G may each independently be an organic light-emitting diode (OLED). When the light-emitting element is an OLED, the light-emitting layer provided in the light-emitting element of each color is, for example, an organic light-emitting layer formed by a vapor deposition method.

[0076] 8 , the display device 200 includes a barrier layer 152, a thin-film transistor layer 170 including a transistor TR, a light-emitting element 110R that emits red light, a light-emitting element 110B that emits blue light, a light-emitting element 110G that emits green light, a bank 140 (transparent resin layer), a sealing layer 180, and a functional film 185, which are provided on a substrate 151 in this order from the substrate 151 side. Note that the substrate 151 on which the barrier layer 152, the thin-film transistor layer 170 including a transistor TR, and a plurality of first electrodes 20 are provided in this order from the substrate 151 side as shown in FIG. 8 is referred to as a substrate (active matrix substrate) 11.

[0077] The substrate 151 may be, for example, a resin substrate made of a resin material such as polyimide, or a glass substrate. When the display device 200 is a non-flexible display device, the substrate 151 may be a glass substrate.

[0078] The barrier layer 152 is a layer that prevents foreign substances such as water and oxygen from penetrating the transistor TR, the light emitting element 110R, the light emitting element 110B, and the light emitting element 110G. The barrier layer 152 can be formed, for example, by a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a laminate film of these, formed by a CVD method. In the display device 200, the light emitting element 110R, the light emitting element 110B, and the light emitting element 110G each have a water-soluble resin layer in each of the functional layers 90R, 90B, and 90G, thereby preventing moisture (humidity) that has permeated the barrier layer 152 from penetrating into the light emitting layer.

[0079] The transistor TR portion of the thin film transistor layer 170 including the transistor TR includes a semiconductor film SEM and doped semiconductor films SEM′ and SEM″, an inorganic insulating film 171, a gate electrode G, an inorganic insulating film 172, an inorganic insulating film 173, a source electrode S and a drain electrode D, and a planarizing film 174.

[0080] The semiconductor films SEM, SEM', and SEM'' may be made of, for example, low-temperature polysilicon (LTPS) or an oxide semiconductor (for example, an In-Ga-Zn-O based semiconductor). In this embodiment, the case where the transistor TR has a top-gate structure will be described as an example, but the present invention is not limited to this, and the transistor TR may also have a bottom-gate structure.

[0081] The gate electrode G and the source electrode S and drain electrode D can be made of a single layer or a multilayer film of a metal containing at least one of aluminum, tungsten, molybdenum, tantalum, chromium, titanium, and copper, for example.

[0082] The inorganic insulating films 171, 172, and 173 can be formed of, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a laminated film thereof, which are formed by a CVD method. The planarizing film 174 can be formed of, for example, a coatable organic material such as polyimide or acrylic.

[0083] The first electrodes 20 of the light emitting elements 110R, 110B, and 110G are provided above the planarization film 174, and insulating banks 140 (transparent resin layers) are provided to cover the edges of each of the plurality of first electrodes 20. The banks 140 constitute non-light emitting regions in the display area DA, and can be formed by applying an organic material such as polyimide or acrylic and then patterning it by photolithography, for example.

[0084] The sealing layer 180 is a light-transmitting film and can be composed of, for example, an inorganic sealing film 181 covering the second electrode 70, an organic film 182 above the inorganic sealing film 181, and an inorganic sealing film 183 above the organic film 182. The sealing layer 180 prevents foreign substances such as water and oxygen from penetrating into the light-emitting elements 110R, 110B, and 110G. The display device 200 includes a water-soluble resin layer in each of the functional layers 90R, 90B, and 90G, thereby preventing moisture that has permeated the sealing layer 180 from penetrating into the light-emitting layers.

[0085] The functional film 185 is, for example, a film having at least one of an optical compensation function and a protection function.

[0086] [Display Device 210 According to One Modification] The display device according to an embodiment of the present disclosure is not limited to the above embodiment. For example, as shown in Fig. 9, a display device 210 according to an embodiment includes a display area DA in which light-emitting elements 101R, 101B, and 101G are manufactured in a series of processes.

[0087] The light-emitting elements 101R, 101B, and 101G and the banks 141 in the non-light-emitting regions 80A and 80B are formed on a substrate 12 that includes a first electrode 21. The substrate 12 that includes the first electrode 21 may be the active matrix substrate described above.

[0088] In the light-emitting elements 101R, 101B, and 100G, the edges of the multiple first electrodes 21 are insulated by banks 141. Each of the first electrodes 21 is an anode. The light-emitting elements 101R, 101B, and 100G share a first charge transport layer 31 that is continuous with each other and formed in a single process in the display area DA, and the first charge transport layer 31 may be a hole transport layer. The light-emitting elements 101R, 101B, and 100G share a water-soluble resin layer 41 that is continuous with each other and formed in a single process in the display area DA. Similarly, the light-emitting elements 101R, 101B, and 100G share a second charge transport layer 61 that is continuous with each other and a second electrode 71 that is a cathode and that is formed in a single process in the display area DA. The second charge transport layer 61 is an electron transport layer.

[0089] In the display device 210, the light-emitting element 101R includes, in this order in the light-emitting region, a first electrode 21, a first charge transport layer 31, a water-soluble resin layer 41 that is the first water-soluble resin layer, a light-emitting layer 51R, a water-soluble resin layer 41B that is the second water-soluble resin layer, a second charge transport layer 61, and a second electrode 71. The light-emitting element 101B includes, in this order in the light-emitting region, a first electrode 21, a first charge transport layer 31, a first water-soluble resin layer 41, a light-emitting layer 51B, a second water-soluble resin layer 41A, a second charge transport layer 61, and a second electrode 71. The light-emitting element 100G comprises a first electrode 21, a first charge transport layer 31, a first water-soluble resin layer 41A, a light-emitting layer 51G, a second charge transport layer 61, and a second electrode 71 in this order in the light-emitting region.

[0090] In the display device 210, the thicknesses of the water-soluble resin layer 41A, the water-soluble resin layer 41B, and even the water-soluble resin layer 41 may be adjusted to adjust the carrier gap according to the type of light-emitting material contained in each of the light-emitting layers 51R, 51B, and 51G.

[0091] In the display device 210, an outer peripheral edge including the outer peripheral end face of the light-emitting layer 51R and an outer peripheral edge including the outer peripheral end face of the light-emitting layer 51B are provided on the non-light-emitting region 80B, and an outer peripheral edge including the outer peripheral end face of the light-emitting layer 51B and an outer peripheral edge including the outer peripheral end face of the light-emitting layer 51G are provided on the non-light-emitting region 80A. In the display device 210, the end faces of the light-emitting layer 51R, the light-emitting layer 51B, and the light-emitting layer 51G are provided on the non-light-emitting region 80A or 80B, respectively, thereby preventing the light-emitting material of the other light-emitting layers from being mixed into the light-emitting region. Furthermore, the light-emitting layer 51R, the light-emitting layer 51B, and the light-emitting layer 51G are provided over a wide range not only in the light-emitting region but also in the non-light-emitting regions 80A and 80B, so that quantum dots, which are the light-emitting material, are formed to a uniform thickness in the light-emitting region.

[0092] [Display Device 220 According to a Modified Example] A display device according to an embodiment of the present disclosure is not limited to the above embodiment. For example, as shown in Fig. 10, a display device 220 according to an embodiment includes light-emitting elements 101R', 101B', and 100G', where the light-emitting element 101R' includes a light-emitting layer 52R that emits red light, the light-emitting element 101B' includes a light-emitting layer 52B that emits blue light, and the light-emitting element 100G' includes a light-emitting layer 52G that emits green light. In the display device 220 according to an embodiment, the light-emitting elements 101R', 101B', and 100G' are provided as light-emitting regions through a series of processes.

[0093] Each of the light-emitting elements 101R', 101B', and 101G' includes a first electrode 21 that is an independent anode in the display area DA, and shares a first charge transport layer 31, a water-soluble resin layer 41, a second charge transport layer 61, and a second electrode 71 that are continuous with each other and formed in a single process. The first charge transport layer 31 is a hole transport layer, the second charge transport layer 61 is an electron transport layer, and the second electrode 71 is a cathode.

[0094] In the display device 220, in the non-light-emitting region 81A surrounding the light-emitting elements 101R', 101B', and 100G', the outer peripheral edge portion including the outer peripheral end face of the light-emitting layer 52B, the water-soluble resin layer 42A, and the outer peripheral edge portion including the outer peripheral end face of the light-emitting layer 52R are superimposed in this order, so that the light-emitting layer 52R and the light-emitting layer 52B are not in direct contact with each other. Also, in the non-light-emitting region 81A, the outer peripheral edge portion of the light-emitting layer 52R is covered with the water-soluble resin layer 42B.

[0095] In addition, in the non-light-emitting region 81B of the display device 220, the outer peripheral end portion including the outer peripheral end surface of the light-emitting layer 52G, the water-soluble resin layer 42A, and the outer peripheral end portion including the outer peripheral end surface of the light-emitting layer 52G overlap each other, so that the light-emitting layer 52B and the light-emitting layer 52G are not in direct contact with each other.

[0096] In one embodiment of the display device 220, the outer peripheral edge of the light-emitting layer 52R is separated from the outer peripheral edge of the light-emitting layer 52B by a water-soluble resin layer 42A, the outer peripheral edge of the light-emitting layer 52B is separated from the outer peripheral edge of the light-emitting layer 52G by a water-soluble resin layer 41A, and the outer peripheral edge of the light-emitting layer 52G is coated with a water-soluble resin layer 42B. As a result, the light-emitting layer 52R, the light-emitting layer 51B, and the light-emitting layer 51G are provided over a wide range, not only in the light-emitting region but also in the non-light-emitting regions 81A and 81B, thereby forming a film of quantum dots, which are a light-emitting material, with a uniform thickness within the light-emitting region. Furthermore, in the display device 220, the outer peripheral edges of the light-emitting layers 51R, 51B, and 51G do not contact each other in the non-light-emitting regions 81A and 81B, so that the light-emitting materials used to form the light-emitting layers 51R, 51B, and 51G do not mix colors in the light-emitting region.

[0097] <Manufacturing Method of Light-Emitting Device> A manufacturing method of a light-emitting device and a display device according to an embodiment of the present disclosure will be described with reference to Figures 11 to 25. As shown in Figures 11 to 25, the manufacturing method of a light-emitting device and a display device according to an embodiment of the present disclosure includes the steps of (i) applying a water-soluble resin composition (composition) containing a water-soluble resin and a positive photosensitizer to form a water-soluble resin layer, (ii) exposing the water-soluble resin layer to light, and developing a pattern, (iii) forming a light-emitting layer on the developed pattern, and (iv) peeling and developing the light-emitting layer on the pattern by peeling off a portion of the water-soluble resin layer, thereby manufacturing a light-emitting device 101B" on a substrate 13. Furthermore, by repeating the steps (i) to (iv), a display device 230 including a plurality of light-emitting devices 101B", 101R", and 101G" on a substrate 13 is manufactured.

[0098] Below, a manufacturing method will be described in which a pattern is developed in a portion of the water-soluble resin layer by exposing the portion, and a pattern of the light-emitting layer is formed without exposing the remaining portion. However, the manufacturing method of a light-emitting element and a display device according to an embodiment of the present disclosure is not limited to a manufacturing method in which only a portion of the composition is exposed. The water-soluble resin layer can be formed not only by a portion that is exposed, but also by a portion that is not exposed. In other words, the water-soluble resin layer is a layer formed by applying at least a composition for forming the water-soluble resin layer, and whether or not the composition is exposed is not an essential configuration. Although not shown, after application, the composition for forming the water-soluble resin layer may be exposed or not exposed entirely.

[0099] 11 , a first electrode 22 is formed on a substrate 13 on which a water-soluble resin layer is to be formed by a general electrode formation method. The first electrode 22 may be made of an electrode material that reflects visible light, and the first electrode 22 may be formed by a general electrode formation method, such as a physical vapor deposition (PVD) method such as vacuum deposition, sputtering, EB deposition, or ion plating, or a chemical vapor deposition (CVD) method. Furthermore, the first electrode 22 may be patterned by, but is not limited to, photolithography or an inkjet method.

[0100] Although not shown, insulating banks may be formed between the first electrodes 22 on the substrate 13 .

[0101] When forming a hole injection layer as the first charge transport layer 32 on the substrate 13, a dispersion liquid containing the above-mentioned nanoparticles such as NiO as a hole injection material and a polar solvent such as water, ethanol, or dimethyl sulfoxide may be prepared, and the dispersion liquid may be applied to form the hole injection layer.

[0102] When forming a hole transport layer as the first charge transport layer 32 on the substrate 13, a composition containing the above-mentioned photosensitive hole transport material and a photoacid generator is prepared, and the composition is applied to form the hole transport layer. Examples of the photoacid generator include triphenylsulfonium salts and diphenyliodonium salts having fluoroalkylsulfonic acid as the anion.

[0103] The dispersion or composition for forming the first charge transport layer 32 may be applied to the subpixels of a plurality of light-emitting elements collectively by spin coating, or may be applied separately to each subpixel by inkjet printing, etc. When the first charge transport layer 32 contains a photosensitive hole transport material, it is preferable to apply the layer to the substrate 13 and then expose it to light to cure the photosensitive hole transport material.

[0104] FIG. 11 is a diagram for explaining an outline of the process from the step of forming the water-soluble resin layer 43A to the step of exposing the water-soluble resin layer 43A.

[0105] The water-soluble resin layer 43A is formed from a water-soluble resin composition for forming a water-soluble resin layer. The water-soluble resin composition may contain the water-soluble resin described above, a positive photosensitizer, a solvent, and water. The water-soluble resin is as described in the section on the water-soluble resin layer provided in the light-emitting element.

[0106] The water-soluble resin composition may contain 1 to 500 parts by mass of a positive photosensitizer relative to 100 parts by mass of a water-soluble resin as a solid content.

[0107] The positive photosensitizer contained in the water-soluble resin composition is decomposed (also called depolymerization) by irradiation with light, and protons (H ＋ Any compound capable of generating a carboxylic acid group such as benzophenone (DBQ) and an organic compound having an acid group such as a carboxylic acid group or a sulfonic acid group may be used. For example, organic compounds having a carboxylic acid group include indenecarboxylic acid, phthalic acid, and derivatives thereof. The positive photosensitizer may typically be a diazoquinone compound. Therefore, the following description of the positive photosensitizer will be given using a typical example of a diazoquinone compound. Examples of diazoquinone compounds include diazoquinones such as diazobenzoquinone (DBQ) and diazonaphthoquinone (DNQ), and derivatives thereof.

[0108] The diazoquinone derivative may be, for example, a compound in which a diazoquinone moiety and a residue derived from a compound having a hydroxyl group or an amino group are bonded via an ester bond or an amide bond. Here, the diazoquinone moiety may have, for example, a sulfonyl group to form the ester bond or the amide bond. The diazoquinone compound may be a compound having an ester bond or an amide bond derived from the sulfonyl group of the diazoquinone moiety and the hydroxyl group or the amino group of the compound. Here, the residue derived from a compound having a hydroxyl group means an alcohol residue, and the residue derived from a compound having an amino group means an amine residue.

[0109] When the compound that forms an ester bond or amide bond with the diazoquinone moiety has a divalent or higher hydroxyl group or amino group, the conversion rate of the hydroxyl group or amino group of the compound by the diazoquinone sulfonyl moiety is preferably 30% or more. Furthermore, although not limited thereto, the conversion rate of the hydroxyl group or amino group of the compound by the diazoquinone moiety may be substantially 100 mol%. This allows for favorable control of the solubility of the water-soluble resin layer in a developer before and after exposure. The conversion rate of the diazoquinone moiety is defined as the conversion rate of a hydroxyl group in the compound to an ester bond, or the conversion rate of an amino group in the compound to an amide bond, and is calculated using the following formula: (number of moles of diazoquinone moiety) / (number of moles of hydroxyl groups and amino groups in the compound before conversion to diazoquinone moiety) × 100

[0110] Examples of the derivatives of diazoquinone include diazoquinone sulfonic acid esters and diazoquinone sulfonic acid amides.

[0111] Examples of diazoquinone sulfonate esters include diazobenzoquinone compounds such as 1,2-benzoquinone diazo-4-sulfonate ester and 1,2-benzoquinone diazo-5-sulfonate ester, and diazonaphthoquinone compounds such as 1,2-naphthoquinone diazo-5-sulfonate ester and 1,2-naphthoquinone diazo-4-sulfonate ester. The diazoquinone sulfonic acid derivatives may be diazo-coupled.

[0112] Further, examples of the diazoquinone derivatives include diazoquinone derivatives in which hydrogen atoms constituting part of the hydroxyl group or amino group of a compound having the hydroxyl group or amino group are converted into diazoquinone sulfonyl moieties.

[0113] In the diazoquinone compound, the compound for forming the residue (alcohol residue) derived from the compound having a hydroxyl group can be a compound having a phenolic hydroxyl group.The compound having a phenolic hydroxyl group can be a phenol having a monovalent hydroxyl group, such as phenol, naphthol, etc., a phenol having a divalent or higher hydroxyl group, such as catechol, pyrogallol, etc., a phenol having a divalent or higher phenolic hydroxyl group, such as bisphenol, trisphenol, tetrakisphenol, etc., or a phenolic resin, such as novolac phenolic resin. Examples of compounds having a phenolic hydroxyl group include 4,4',4"-ethylidynetrisphenol, 2,3,4-trihydroxybenzophenone, 2,3,4,4'-tetrahydroxybenzophenone, α,α-bis(4-hydroxyphenyl)-4-(4-hydroxy-α,α-dimethylbenzyl)-ethylbenzene, 4,4'-(1-{4-[1-(4-hydroxyphenyl)-1-methylethyl]phenyl}ethylidene)diphenol, and novolac-type cresol resins.

[0114] Further, examples of diazoquinone sulfonamides include compounds in which a hydroxyl group of an amino alcohol is ester-bonded to a resin having a carboxyl group, and a 1,2-benzoquinonediazo 4-sulfonyl group or the like is then introduced to the amino group, thereby forming a sulfonamide.

[0115] Examples of the solvent contained in the composition for forming the water-soluble resin layer include water, alcohols such as ethanol, isopropyl alcohol (IPA), and ethylene glycol, polar solvents such as N-methylpyrrolidone (NMP) and dimethyl sulfoxide (DMSO), nitriles such as acetonitrile, ketones such as acetone and methyl ethyl ketone, and polyethylene glycol monomethyl ether acetate (PEGMEA).

[0116] The positive photosensitizer contained in the composition for forming the water-soluble resin layer is not limited to a diazoquinone compound. The positive photosensitizer may be, for example, at least one positive photosensitizer selected from the group consisting of the above-mentioned diazoquinone compounds, polyolefin sulfone, and polyphthalaldehyde. The polyolefin sulfone may be a photosensitive polyolefin sulfone having photosensitivity, such as a polyolefin sulfone having a dye that generates an amine upon absorbing light introduced into the side chain of the polyolefin sulfone via a carbon bonded to the sulfone group in the polyolefin sulfone chain. The polyphthalaldehyde may be a photosensitive polyphthalaldehyde, such as polyphthalaldehyde (PPA) and photosensitive polyphthalaldehydes such as polyphthalaldehyde having an oxime ether terminal.

[0117] In addition, the composition for forming the water-soluble resin layer may contain, as additives, for example, a photosensitizer such as acetophenone, a chemical sensitizer, a filler, a colorant, a stabilizer such as an antioxidant, and a surfactant such as a leveling agent, an antifoaming agent, or a dispersant.

[0118] The composition for forming the water-soluble resin layer may also contain a crosslinking agent. The crosslinking agent may be a crosslinking agent that crosslinks with the acid generated when the diazoquinone compound contained in the composition for forming the water-soluble resin layer is exposed to light, and examples thereof include novolac phenolic resins, epoxy resins, melamine resins, unsaturated polyester resins, polyimide resins, diallyl phthalate, and urethane resins. This allows the degree of crosslinking to be controlled by controlling the content of the crosslinking agent and the baking conditions when forming the photoresist layer, thereby achieving the effect of controlling the solubility and obtaining a more accurate pattern. The content of the crosslinking agent in the composition for forming the water-soluble resin layer is not limited, but may be, for example, more than 0 parts by weight, preferably 100 parts by weight or less, and more preferably 50 parts by weight or less, based on 100 parts by weight of the total of the water-soluble resin and the diazoquinone compound.

[0119] The composition for forming the water-soluble resin layer is applied to the subpixels of the plurality of light-emitting elements collectively by dip coating or spin coating, thereby providing the water-soluble resin layer 43A. The water-soluble resin layer 43A may then be heated and dried at a temperature in the range of 80 to 150° C., for example. The composition for forming the water-soluble resin layer is not limited to being applied to the subpixels collectively, and may be applied separately to each subpixel by, for example, an inkjet method or the like.

[0120] Thereafter, as shown in FIG. 11 , the water-soluble resin layer 43A formed on the first charge transport layer 32 may be exposed to light using a photomask 300 having a desired pattern. Examples of light for exposing the water-soluble resin layer 43A include ultraviolet light with a wavelength of approximately 150 to 450 nm, and electron beams. The ultraviolet light may be g-line (wavelength 436 nm), h-line (wavelength 405 nm), or i-line (wavelength 365 nm) from a high-pressure mercury lamp, or may be an excimer laser (wavelength 150 to 248 nm). When exposing the water-soluble resin layer 43A, the thickness t1 of the water-soluble resin layer 43A may be adjusted by designing the wavelength and exposure dose. The exposure dose is not limited, but may be, for example, 1 mJ / cm. ２ ~1000mJ / cm ２ It is sufficient if it is within the range.

[0121] FIG. 12 is a diagram illustrating an outline of the process of washing the water-soluble resin layer 43A with a developer and developing a pattern in the exposed areas of the water-soluble resin layer 43A. Acidic compounds such as indene carboxylic acid derivatives are generated in the exposed areas of the water-soluble resin layer 43A, thereby increasing its solubility in an alkaline aqueous developer. Therefore, a desired pattern can be developed in the water-soluble resin layer 43A by washing with an alkaline aqueous developer. The desired pattern can be developed by, for example, immersing the water-soluble resin layer 43A in a beaker (not shown) containing the developer. The developer can be supplied to the water-soluble resin layer 43A by spraying the developer using a spray nozzle, for example.

[0122] The developer may be an aqueous alkaline developer or an organic solvent developer, and is preferably an aqueous alkaline developer. Examples of the alkaline developer include aqueous developers containing alkalis such as potassium hydroxide (KOH) and tetramethylammonium hydroxide (TMAH).

[0123] The water-soluble resin layer 43A after development may be dried by heating at a temperature of, for example, 50 to 150°C. The water-soluble resin layer 43A has a thickness t of about 100 nm to 5000 nm in the unexposed areas, and the thickness t of the water-soluble resin layer 43A may be adjusted, for example, by the amount of coating of the composition for forming the water-soluble resin layer. The thickness t1 of the exposed areas is adjusted to 20 nm or less. As described above, the thickness t1 may be adjusted by the amount of exposure when exposing the water-soluble resin layer 43A.

[0124] 13 is a diagram illustrating an outline of the process of forming a light-emitting layer 53B on a pattern formed in the water-soluble resin layer 43A. The light-emitting layer 53B can be formed by applying a composition containing a light-emitting material onto the water-soluble resin layer 43A. The light-emitting layer 53B is no different from the light-emitting layer 53B' provided in the unexposed areas of the water-soluble resin layer 43A, except that it is formed in the exposed areas of the water-soluble resin layer 43A. In the process of forming the light-emitting layer, it is sufficient that the light-emitting layer 53B is formed; the light-emitting layer 53B' is not necessarily formed. The water-soluble resin layer 43A is the first water-soluble resin layer in the area that contacts the back surface of the light-emitting layer 53B.

[0125] The light-emitting layer can be formed by applying a dispersion of quantum dots to each subpixel separately by spin coating, inkjet printing, etc. The quantum dot dispersion contains a solvent such as hexane, toluene, or phenylcyclohexane, and may also contain a dispersing material such as thiol or amine.

[0126] When the light-emitting material of the light-emitting layer contains quantum dots having a shell of a metal sulfide, which is a sulfide semiconductor, as an inorganic ligand, the quantum dots may be produced in an inert gas atmosphere as follows.

[0127] First, to obtain a precursor of a sulfide semiconductor, a dispersion containing a metal source such as a metal acetate, a metal nitrate, or a metal halide salt and a sulfur source such as thiourea, N-methylthiourea, or 1,3-dimethylthiourea is prepared. The dispersion may contain, as a precursor, a metal complex in which thiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea, or thioacetamide is coordinated to a metal atom.

[0128] Next, a polar solvent in which an excess amount of halide ions relative to the quantum dots dissolves is mixed with a nonpolar solvent in which quantum dots with carbon chains as organic ligands are dispersed, and the organic ligands of the quantum dots are substituted with halide ions. Subsequently, a dispersion of a sulfide semiconductor precursor and a dispersion of quantum dots whose organic ligands have been substituted with halide ions are mixed and stirred.

[0129] The polar solvent for producing quantum dots may include at least one of polar solvents such as dimethyl sulfoxide (DMSO) and N,N-dimethylformamide (DMF), esters or lactones such as methyl acetate, ethers such as tetrahydrofuran, tetrahydrothiophene, and diethyl sulfide. The nonpolar solvent is preferably toluene, hexane, octane, octadecene, or the like, and is preferably a nonpolar solvent that is immiscible with the polar solvent for producing quantum dots.

[0130] When the polar solvent in the dispersion of the sulfide semiconductor precursor and the non-polar solvent in the dispersion of the quantum dots substituted with halide ions are separated into two phases, quantum dots having a shell of the sulfide semiconductor as an inorganic ligand can be produced in the polar solvent phase.

[0131] A dispersion of quantum dots in a polar solvent is applied onto the water-soluble resin layer 43A, and the laminate is heated to 80°C to 500°C to form an emitting layer containing quantum dots having a shell of sulfide semiconductor as an inorganic ligand.

[0132] 14 is a diagram illustrating an outline of a process of peeling and developing the light-emitting layer 53B by peeling off the water-soluble resin layer 43A except for the pattern formed on the water-soluble resin layer 43A. In the peel-and-develop process, the light-emitting layer 53B' is peeled off from the substrate 13 together with the unexposed portions of the water-soluble resin layer 43A by a developer. As a result, the light-emitting layer 53B is developed into a desired pattern on the water-soluble resin layer 43A.

[0133] Developers used in the peel-and-develop step include alkaline developers and organic solvent developers, with the use of an organic solvent developer being preferred. The organic solvent developer can be a solvent contained in the composition for forming the water-soluble resin layer described above, and examples thereof include organic solvents such as propylene glycol monomethyl ether acetate (PGMEA), acetone, isopropyl alcohol (IPA), dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP). By using an organic solvent developer as the developer, the portions of the water-soluble resin layer 43A containing the positive photosensitizer can be successfully peeled off together with the light-emitting layer 53B', and the light-emitting layer 53B can be developed to have a desired pattern.

[0134] As shown in Figure 14, after peel-off development, the light-emitting layer 53B and the water-soluble resin layer 43A in contact with its back surface are formed. Therefore, even if moisture is encapsulated in the first charge transport layer 32 during the manufacturing process of the first charge transport layer 32, it is expected that the water-soluble resin layer 43A will prevent moisture from penetrating into the light-emitting layer 53B.

[0135] The developer may be supplied to the water-soluble resin layer 43A by immersion in a beaker (developer tank) containing the developer, or by spraying the developer using a spray nozzle or the like. For example, as shown in Fig. 15, the thickness of the unexposed portion of the water-soluble resin layer 43A may be adjusted according to the thickness t1. The thickness of the unexposed portion of the water-soluble resin layer 43A may be adjusted by the time for immersion in the beaker containing the developer, or the amount of developer supplied using a spray nozzle or the like.

[0136] FIG. 16 is a diagram for explaining an outline of the step of forming the water-soluble resin layer 43B (step of forming the second water-soluble resin layer).

[0137] The water-soluble resin composition for forming the water-soluble resin layer 43B may have the same composition as or a different composition from the water-soluble resin composition for forming the water-soluble resin layer 43A. For example, the weight average molecular weight of the water-soluble resin contained in the water-soluble resin composition for forming the water-soluble resin layer 43B is preferably larger than the weight average molecular weight of the water-soluble resin contained in the water-soluble resin layer 43A. This allows the water-soluble resin layer 43B to successfully protect the light-emitting layer 53B from a developer supplied in a subsequent process.

[0138] The method for applying the water-soluble resin composition to form the water-soluble resin layer 43B is the same as the method for applying the composition to form the water-soluble resin layer 43A, and therefore the description thereof will be omitted.

[0139] FIG. 17 is a diagram illustrating an outline of the steps from the step of forming the water-soluble resin layer 43B to the step of exposing the water-soluble resin layer 43B. The water-soluble resin layer 43B is exposed through a photomask 301 having a pattern different from that of the photomask 300. More specifically, in the display area DA on the substrate 13, exposure is performed so as to form a pattern that does not overlap at least the light-emitting area of ​​the light-emitting element 101B", as shown in FIG. 25. The conditions for exposure are the same as those for the first exposure step, so a description thereof will be omitted.

[0140] 18 is a diagram illustrating an outline of a process (second developing process) in which the water-soluble resin layer 43B is washed with a developer after the second exposure and a pattern is developed in the exposed areas of the water-soluble resin layer 43B. As in the first developing process, the stripping liquid for developing the water-soluble resin layer 43B is preferably an alkaline aqueous developer. In the second developing process, the surface of the light-emitting layer 53B is protected from the alkaline aqueous developer by being covered with the water-soluble resin layer 43B.

[0141] 19 is a diagram illustrating an outline of a process for forming a light-emitting layer 53R in a pattern provided in the water-soluble resin layer 43B. The light-emitting layer 53R is formed by applying a composition containing a light-emitting material that emits red light onto the water-soluble resin layer 43B. The light-emitting layer 53R' is no different from the light-emitting layer 53B except that it is formed in an unexposed area of ​​the water-soluble resin layer 43B.

[0142] 20 is a diagram illustrating an outline of the process of peeling and developing the light-emitting layer 53R (second peeling and developing process). In the second peeling and developing process, the unexposed portions of the water-soluble resin layer 43B are peeled off together with the light-emitting layer 53R', while leaving a portion of the water-soluble resin layer 43B covering the surface of the light-emitting layer 53B. This allows the light-emitting layer 53R to be developed into a desired pattern, while a portion of the water-soluble resin layer 43B becomes a second water-soluble resin layer that contacts the surface of the light-emitting layer 53R. Furthermore, the water-soluble resin layer 43B can protect the light-emitting layer 53B from the developer used in a subsequent process.

[0143] The developer used in the second peel-and-develop process and the conditions for peel-and-develop are the same as those in the first peel-and-develop process, and therefore a description thereof will be omitted.

[0144] FIG. 21 is a cross-sectional view showing an outline of the process from the step of forming the water-soluble resin layer 43C to the step of exposing the water-soluble resin layer 43C. The water-soluble resin layer 43C is exposed through a photomask 302 having a pattern different from the photomasks 300 and 301. More specifically, in the display area DA on the substrate 13, exposure is performed so as to form a pattern that does not overlap at least the light-emitting areas of the light-emitting elements 101B″ and 101R″, as shown in FIG. 25. The conditions for exposure are the same as those for the first exposure step, so a description thereof will be omitted. The composition for forming the water-soluble resin layer 43C may have the same composition as the compositions for forming the water-soluble resin layers 43A and 43B, or may have a different composition. For example, the water-soluble resin contained in the composition for forming the water-soluble resin layer 43C preferably has a mass-average molecular weight larger than that of the water-soluble resin contained in the water-soluble resin layer 43A, similar to the water-soluble resin contained in the water-soluble resin layer 43B.

[0145] 22 is a diagram illustrating an outline of a process (third developing process) in which the exposed water-soluble resin layer 43C is washed with a developer and a pattern is developed in the water-soluble resin layer 43C. The stripping liquid used to develop the water-soluble resin layer 43C is preferably an alkaline aqueous developer. Because the water-soluble resin layer 43B covers the surface of the light-emitting layer 53B and the water-soluble resin layer 43C covers the surface of the light-emitting layer 53R, the light-emitting layers 53R and 53B are protected from the alkaline aqueous developer used to develop the water-soluble resin layer 43C.

[0146] FIG. 23 is a diagram illustrating an outline of the process for forming the third light-emitting layer 53G. The light-emitting layer 53G is formed by applying a dispersion containing a light-emitting material that emits green light onto the water-soluble resin layer 43C. The preparation of the dispersion containing the light-emitting material for forming the light-emitting layer 53G is similar to the preparation of the dispersion containing the light-emitting material for forming the light-emitting layer 53B, and therefore a description thereof will be omitted. Furthermore, the light-emitting layer 53G′ is identical to the light-emitting layer 53G except that it is formed in the unexposed portion of the water-soluble resin layer 43C. As illustrated in FIG. 23, the water-soluble resin layer 43C is formed as a first water-soluble resin layer in contact with the back surface of the light-emitting layer 53G and as a second water-soluble resin layer in contact with the front surface of the light-emitting layer 53R.

[0147] 24 is a diagram illustrating an outline of the process (third developing process) of washing the water-soluble resin layer 43C with a developer and developing the light-emitting layer 53G on the pattern of the water-soluble resin layer 43C. In the peel-and-develop process for developing the light-emitting layer 53G, a portion of the water-soluble resin layer 43C is left unremoved, and the surface of the light-emitting layer 53R is covered with the water-soluble resin layer 43C. This allows the water-soluble resin layer 43C to function as a second water-soluble resin layer in contact with the surface of the light-emitting layer 53R while developing the desired pattern in the light-emitting layer 53G. This allows the water-soluble resin layer 43C to prevent the light-emitting layer 53R from being exposed to the developer.

[0148] As shown in FIG. 25, a display device 230 according to one embodiment of the present disclosure is manufactured by forming a second charge transport layer 62, which is an electron transport layer, and a second electrode 72, which is a cathode, on a substrate 13 on which light-emitting layers 53R, 53B, and 53G are formed.

[0149] The display device 230 comprises light-emitting elements 101R", 101B", and 100G" that constitute the light-emitting region, and non-light-emitting regions 82A and 82B between the light-emitting elements. In the non-light-emitting regions 82A and 82B, the outer peripheral end surfaces of the light-emitting elements 101R", 101B", and 100G" that constitute the light-emitting region are not in contact with each other due to the presence of the water-soluble resin layer 43 therebetween. The widths of the light-emitting elements 101R", 101B", and 100G" can be adjusted by the pattern of the photomask used when forming the water-soluble resin layer 43.

[0150] The composition used to form the second charge transport layer 62, which is an electron transport layer, may be any composition containing the above-mentioned electron transport material, and the composition may be applied to the substrate 13 on which the light-emitting layers 53R, 53B, and 53G are formed, collectively to the sub-pixels of the plurality of light-emitting elements by a spin coating method, a dip coating method, or the like, or may be applied separately to each sub-pixel by an inkjet method, or the like.

[0151] The second electrode 72 can be formed by a general electrode formation method, such as a physical vapor deposition (PVD) method such as vacuum deposition, sputtering, EB deposition, or ion plating, or a chemical vapor deposition (CVD) method.

[0152] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0153] An embodiment of the present disclosure is described below.

[0154] [Preparation of Resin Composition] Using the materials shown in the [Materials] column below, water-soluble resin compositions for forming the water-soluble resin layers of Samples 1 to 5 were prepared. [Materials] (Water-soluble resin) PVA-PVP graft copolymer A-1 PVA ratio: 0.3 PVA-PVP graft copolymer A-2 PVA ratio: 0.4 PVA-PVP graft copolymer A-3 PVA ratio: 0.5 PVA-PVP graft copolymer B-1 PVA ratio: 0.6 PVA-PVP graft copolymer B-2 PVA ratio: 0.7 PVA-PVP graft copolymer B-3 PVA ratio: 0.8 Polyvinyl alcohol-1 Polyvinylpyrrolidone-1 The PVA ratio in the water-soluble resin was calculated based on the following formula: PVA ratio = PVA / (PVA+PVP) PVA: Molar amount of monomer units constituting PVA polymer units PVP: Molar amount of monomer units constituting PVP polymer units "PVA-PVP graft copolymer A" is a graft copolymer in which the hydroxyl groups of PVA in PVA-PVP are substituted with hydrophobic groups, and "PVA-PVP copolymer B" is a pure PVA-PVP graft copolymer in which the hydroxyl groups of PVA are not substituted with hydrophobic groups. PVP is polyvinylpyrrolidone. Solvent: dimethyl sulfoxide (DMSO)

[0155] 10 g of PVA-PVP graft copolymer A-1 was weighed out and dissolved in 100 mL of DMSO to prepare a solution of PVA-PVP graft copolymer A-1 as a water-soluble resin composition of Sample 1.

[0156] The water-soluble resin composition of Sample 2 was prepared according to the same procedure as for the water-soluble resin composition of Sample 1, except that PVA-PVP graft copolymer A-1 was changed to PVA-PVP graft copolymer A-2. Similarly, the PVA-PVP graft copolymer A-1 was changed to PVA-PVP graft copolymer A-3, PVA-PVP graft copolymer B-1, PVA-PVP graft copolymer B-2, PVA-PVP graft copolymer B-3, polyvinyl alcohol 1, or polyvinylpyrrolidone 1, respectively, to prepare water-soluble resin compositions of Samples 3 to 8.

[0157] [Preparation of Water-Soluble Resin Layer] The water-soluble resin composition of Sample 1 was applied to a glass substrate (2.5 cm x 2.5 cm) by spin coating, and then heated and dried at 80°C for 3 minutes. In this way, the water-soluble resin layer of Sample 1 was formed on the glass substrate. In this way, the water-soluble resin layer of Sample 1 (film thickness 1000 nm) was formed on the glass substrate. In addition, water-soluble resin layers (film thickness 1000 nm) of Samples 2 to 8 were each separately formed on a glass substrate according to the same procedure as for the water-soluble resin composition of Sample 1.

[0158] [Evaluation of Dissolution Rate of Water-Soluble Resin Layer] Each of the water-soluble resin layers of Samples 1 to 5 was immersed in pure water (room temperature of about 23°C) for 60 seconds, then removed, and heated at room temperature of 23°C in a N ２ The film was blow-dried. Thereafter, the film thickness of the water-soluble resin layer was measured. The water dissolution rate was calculated based on the difference in film thickness before and after immersion and the immersion time in pure water. Table 1 shows the evaluation results of the water-soluble resin, PVA ratio, and water dissolution rate contained in the water-soluble resin layer of Samples 1 to 8.

[0159]

[0160] The evaluation results of the water dissolution rates of Samples 1 to 8 confirmed that the higher the PVA ratio, the slower the water dissolution rate; in other words, water-soluble resin layers containing PVA tend to have higher water resistance. Furthermore, the water-soluble resin layers of Samples 1 to 6 possess the water resistance of the PVA block while also achieving the dissolution rate of the PVP block, making them more preferable from the perspective of controlling the film thickness, i.e., forming a film thickness of several micrometers. The evaluation of Samples 1 to 8 suggests that the water-soluble resin layer, which is a copolymer, can effectively protect the light-emitting layer, thereby reducing the possibility of deterioration due to moisture penetration into the light-emitting layer. In particular, water-soluble resins containing graft copolymers are expected to be preferable from the perspective of controlling the film thickness.

[0161] 10, 11, 12, 13 Substrate 20, 21, 22 First electrode (anode) 30, 31, 32 First charge transport layer (hole transport layer, hole injection layer) 40, 40A, 40B, 40C, 40D, 40E, 43, 43A, 43B, 43C Water-soluble resin layer 41 First water-soluble resin layer (first water-soluble resin layer) 41A, 41B, 42A, 42B Second water-soluble resin layer (second water-soluble resin layer) 50, 50A Light-emitting layer 51R, 52R, 53R Light-emitting layer that emits red light 51B, 52B, 53B Light-emitting layer that emits blue light 51G, 53B, 53G Light-emitting layer that emits green light 60, 60A, 60B, 60C, 61, 62 Second charge transport layer (electron transport layer) 70, 71, 72 Second electrode (cathode) 100, 101, 102, 103, 104, 105 Light-emitting element 101R, 101R', 101R", 110R Light-emitting element that emits red light 101B, 101B', 110B", 110B Light-emitting element that emits blue light 100G, 100G', 100G", 110G Light-emitting element that emits green light 200, 210, 220, 230 Display device

Claims

1. a first electrode and a second electrode; a plurality of charge transport layers laminated between the first and second electrodes; a light-emitting layer laminated between the plurality of charge transport layers; at least one water-soluble resin layer provided so as to contact at least one surface selected from the front surface, back surface, and outer peripheral end surface of the light-emitting layer; and the water-soluble resin layer contains a water-soluble resin; a light-emitting device, wherein the water-soluble resin layer contains a positive photosensitive agent.

2. The light-emitting device according to claim 1, wherein the light-emitting layer contains quantum dots.

3. The light-emitting device according to claim 2, wherein the light-emitting layer containing the quantum dots contains a metal sulfide.

4. A first electrode and a second electrode; a plurality of charge transport layers laminated between the first and second electrodes; a light-emitting layer laminated between the plurality of charge transport layers; at least one water-soluble resin layer provided so as to contact at least one surface selected from the front surface, back surface, and outer peripheral end surface of the light-emitting layer; and the water-soluble resin layer contains a water-soluble resin; the water-soluble resin contains a graft copolymer or a block copolymer; the light-emitting device, wherein the graft copolymer and the block copolymer include at least two polymer units derived from different hydrophilic monomers.

5. The light-emitting device according to claim 4, wherein the polymer unit includes a polymer unit in which a vinyl alcohol monomer unit is polymerized.

6. The light-emitting device according to claim 4 or 5, wherein the polymer unit includes a polymer unit in which an N-vinylpyrrolidone monomer unit is polymerized.

7. The light-emitting device according to any one of claims 1 to 5, wherein the charge transport layer facing the front surface is an electron transport layer, and the charge transport layer facing the back surface is a hole transport layer.

8. The light-emitting device according to claim 1, wherein the water-soluble resin layer is provided so as to contact the back surface.

9. A first electrode and a second electrode; a plurality of charge transport layers laminated between the first and second electrodes; a light-emitting layer laminated between the plurality of charge transport layers; at least one water-soluble resin layer provided so as to contact at least one surface selected from the front surface, back surface, and outer peripheral end surface of the light-emitting layer; and the water-soluble resin layer contains a water-soluble resin; the water-soluble resin layer is provided so as to contact the back surface; a light-emitting device, comprising two layers of the water-soluble resin layer, and a second layer of the water-soluble resin layer is provided so as to contact the front surface.

10. The light-emitting element according to claim 9, wherein the water-soluble resin layer is provided so as to contact the outer peripheral end face of the light-emitting layer.

11. The first and second electrodes, a plurality of charge transport layers laminated between the first and second electrodes, a light-emitting layer laminated between the plurality of charge transport layers, at least one water-soluble resin layer provided so as to contact at least one surface selected from the front surface, back surface, and outer peripheral end face of the light-emitting layer, wherein the water-soluble resin layer contains a water-soluble resin, the water-soluble resin layer is provided so as to contact the back surface, the water-soluble resin layer has a region in contact with the back surface and a region not in contact with the back surface, and the thickness of the water-soluble resin layer in the region not in contact with the back surface is thicker or thinner than the thickness of the water-soluble resin layer in the region in contact with the back surface.

12. The light-emitting element according to any one of claims 8 to 11, wherein the thickness of the water-soluble resin layer in the region in contact with the back surface is 20 nm or less.

13. The first and second electrodes, a plurality of charge transport layers laminated between the first and second electrodes, a light-emitting layer laminated between the plurality of charge transport layers, at least one water-soluble resin layer provided so as to contact at least one surface selected from the front surface, back surface, and outer peripheral end face of the light-emitting layer, wherein the water-soluble resin layer contains a water-soluble resin, the charge transport layer and the water-soluble resin layer are provided so as to surround and contact the outer peripheral end face.

14. A substrate, A display device including a plurality of light-emitting elements on the substrate, wherein each of the plurality of light-emitting elements is selected from the light-emitting elements according to any one of claims 1 to 5, 8 to 11, and 13.

15. A substrate, A display device including a plurality of light-emitting elements on the substrate, The first and second electrodes, a plurality of charge transport layers laminated between the first and second electrodes, a light-emitting layer laminated between the plurality of charge transport layers, at least one water-soluble resin layer provided so as to contact at least one surface selected from the front surface, back surface, and outer peripheral end face of the light-emitting layer, wherein the water-soluble resin layer contains a water-soluble resin, the water-soluble resin layer is provided so as to contact the back surface, Among the plurality of light-emitting elements, one light-emitting element is a light-emitting element provided such that the water-soluble resin layer contacts the back surface, and the remaining light-emitting elements are light-emitting elements provided such that the water-soluble resin layer contacts the front surface and the back surface. Display device.

16. The display device according to claim 14, Comprising a non-light-emitting region surrounding each of the plurality of light-emitting elements, A display device in which the outer peripheral end of the light-emitting layer included in one light-emitting element, the water-soluble resin layer included in the one light-emitting element, and the outer peripheral end of the light-emitting layer included in the light-emitting elements other than the one light-emitting element overlap on the non-light-emitting region, so that the two light-emitting layers do not contact each other.

17. A light-emitting layer, A method for manufacturing a light-emitting element, comprising at least one layer of a water-soluble resin layer provided in contact with the light-emitting layer, The composition for forming the water-soluble resin layer contains a water-soluble resin and a positive photosensitive agent, A step of coating the composition on a substrate to form the water-soluble resin layer, A step of exposing a part of the water-soluble resin layer and developing a pattern in the water-soluble resin layer, A step of forming the light-emitting layer so as to contact the pattern, A method for manufacturing a light-emitting element, including a step of peeling and developing the light-emitting layer on the pattern by peeling at least a part of the water-soluble resin layer other than the pattern.

18. A method for manufacturing a display device including a plurality of light-emitting elements on a substrate by repeating each step included in the method for manufacturing a light-emitting element according to claim 17, By the step of peeling and developing for the first time, the first light-emitting layer is peeled and developed, In the step of forming the second water-soluble resin layer, a water-soluble resin layer is formed so as to cover the surface of the first light-emitting layer, By the step of developing for the second time and the step of forming the light-emitting layer, a second light-emitting layer is formed, In the step of peeling and developing for the second time, a water-soluble resin layer covering the surface of the first light-emitting layer is left. A method for manufacturing a display device.