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

Abstract

A light-emitting element (101) is provided with a first reaction product layer (51) on at least one surface selected from the front surface, the back surface, and the outer peripheral end surface of a light-emitting layer (40) provided between a first electrode (20) and a second electrode (70). The first reaction product layer (51) contains a first reaction product that is the reaction product of a ligand and a base resin and a photosensitive agent.

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] Patent Document 1 describes an inorganic electroluminescence (EL) element having a substrate, a first electrode, at least one insulating layer, a light-emitting layer, and a second electrode, in which the light-emitting layer contains quantum dots and carbon such that the number of carbon atoms and the number of atoms constituting the quantum dots satisfy a predetermined ratio, and the light-emitting layer is disposed in contact with the insulating layer.

[0003] International Publication No. 2007 / 142203

[0004] The light-emitting device described in Patent Document 1 contains quantum dots in its light-emitting layer. The quantum dot-containing dispersion liquid for forming the light-emitting layer contains a ligand in addition to the quantum dots. When the ligand is contained in the light-emitting device, there is a problem in that the light-emitting efficiency of the light-emitting device decreases over time due to the functional group possessed by the ligand.

[0005] A light-emitting device according to an embodiment of the present disclosure has been made in consideration of the above-mentioned problems, and its purpose is to provide a novel light-emitting device and related techniques that can prevent a decrease in luminous efficiency over time in the light-emitting device by using a functional group possessed by a ligand.

[0006] A light-emitting element according to one embodiment of the present disclosure comprises a first electrode and a second electrode, and further comprises, between the first electrode and the second electrode, a light-emitting layer and at least one first reaction product layer provided on at least one surface selected from the front surface, the back surface, and the outer peripheral end surface of the light-emitting layer, wherein the first reaction product layer includes a first reaction product that is a reaction product of a ligand with a base resin and a photosensitizer, and the first reaction product has a molecular structure derived from the ligand.

[0007] Furthermore, a display device according to an embodiment of the present disclosure is a display device having a display area in which a plurality of light-emitting elements are formed on a substrate, and each of the plurality of light-emitting elements is a light-emitting element according to an embodiment of the present disclosure.

[0008] Furthermore, a method for manufacturing a light-emitting element according to an embodiment of the present disclosure is a method for manufacturing a light-emitting element including a light-emitting layer between first and second electrodes, and a first reaction product layer provided on at least one surface of the light-emitting layer, wherein a light-emitting layer composition for forming the light-emitting layer includes quantum dots and a ligand, and a resist agent composition includes a base resin and a photosensitizer, the method including: forming the light-emitting layer by applying the light-emitting layer composition onto the first or second electrode; forming a resist layer by applying the resist agent composition onto the light-emitting layer; and forming a first reaction product layer on the resist layer provided on either surface of the light-emitting layer while forming a pattern in the resist layer by exposing at least a portion of the resist layer, wherein in the step of forming the first reaction product layer, a first reaction product having a molecular structure derived from the ligand is generated by reacting the ligand with the base resin and the photosensitizer.

[0009] The present invention has an effect of providing a novel light-emitting element that can prevent the luminous efficiency of the light-emitting element from decreasing over time due to the functional group of the ligand.

[0010] 1 is a cross-sectional view showing a schematic configuration of a light-emitting element 101 according to an aspect of the present disclosure. FIG. 2 is a cross-sectional view showing a schematic configuration of a light-emitting element 102 according to an embodiment of the present disclosure. FIG. 3 is a cross-sectional view showing a schematic configuration of a light-emitting element 103 according to an embodiment of the present disclosure. FIG. 4 is a cross-sectional view showing a schematic configuration of a light-emitting element 104 according to an embodiment of the present disclosure. FIG. 5 is a cross-sectional view showing a schematic configuration of a light-emitting element 105 according to an embodiment of the present disclosure. FIG. 6 is a cross-sectional view showing a schematic configuration of a light-emitting element 106 according to an embodiment of the present disclosure. FIG. 7 is a cross-sectional view showing a schematic configuration of a light-emitting element 107 according to an embodiment of the present disclosure. FIG. 8 is a plan 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 200 according to an embodiment of the present disclosure. FIG. 10 is a cross-sectional view showing a schematic configuration of a light-emitting element 100. 1A and 1B are cross-sectional views illustrating an outline of a step of forming a light-emitting layer 40R, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure; FIG. 1C is a cross-sectional view illustrating an outline of a step of peeling and developing the light-emitting layer 40R, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure; FIG. 1D is a cross-sectional view illustrating an outline of a step of forming a second reaction product layer 53G, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure; FIG. 1F is a cross-sectional view illustrating an outline of a step of forming a light-emitting layer 40G, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure; FIG. 1G is a cross-sectional view illustrating an outline of a step of peeling and developing the light-emitting layer 40G, which is included in the method for manufacturing a light-emitting element according to an embodiment of the present disclosure; FIG. 1H is a cross-sectional view illustrating an outline of a step of forming a first reaction product layer 51 by exposing a resist layer 84, 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 a step of forming a second base layer 60 included in a method for manufacturing a light-emitting device according to an embodiment of the present disclosure; FIG. 2 is a cross-sectional view showing an outline of a display device 210 including a light-emitting device according to an embodiment of the present disclosure; FIG. 3 is a cross-sectional view showing an outline of a display device 220 including a light-emitting device according to an embodiment of the present disclosure; FIG. 4 is a cross-sectional view showing an outline of a display device 230 including a light-emitting device according to an embodiment of the present disclosure; and FIG. 5 is a cross-sectional view showing an outline of a display device 240 including a light-emitting device according to an embodiment of the present disclosure.

[0011] <Light Emitting Element> First, the configuration of a light emitting element 101 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 101 according to this embodiment.

[0012] In this specification, each layer in each cross-sectional view will be described with the upper surface being the front surface, the lower surface being the back surface, and the surfaces at both ends being the outer peripheral end surfaces.

[0013] The light-emitting element 101 may be a top-emission type or a bottom-emission type. In the light-emitting element 101, 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. In order to make the light-emitting element 101 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.

[0014] 1, the light-emitting element may have a forward stack structure, but is not limited to this and may have an inverted stack structure. A light-emitting element with an inverted stack structure can be constructed by stacking, in order from the first electrode side which is a cathode provided on a substrate, a first functional layer which is an electron transport layer, a reaction product layer, a light-emitting layer, a second functional layer which is a hole transport layer, and a second electrode which is an anode.

[0015] 1 , the light-emitting element 101 includes a functional layer 91 in which a first functional layer 30, a light-emitting layer 40, a reaction product layer 51, and a second functional layer 60 are stacked in this order between a first electrode 20 that is an anode and a second electrode 70 that is a cathode, and the reaction product layer 51 is provided so as to be in contact with the surface of the light-emitting layer 40. The layer stacked between the first and second electrodes is sometimes referred to as a functional layer, and the functional layer may include, as multiple functional layers, a light-emitting layer stacked between the multiple functional layers and a reaction product layer in contact with the light-emitting layer.

[0016] The light emitting element 101 constitutes a light emitting region HR of a display area DA of the display device on the substrate 10. The light emitting region HR of the light emitting element 101 is surrounded by a non-light emitting region NHR on the substrate 10 that does not emit 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] [First Functional Layer] The light-emitting element 101 includes a first functional layer 30 between the first electrode 20 and the light-emitting layer 40. The first functional layer 30, which is a hole transport layer, transports holes from the first electrode 20 side, which is the anode, toward the light-emitting layer 40.

[0020] Although not shown, the first functional layer 30 may be composed of multiple layers from the viewpoint of increasing the hole injection efficiency. When the first functional layer 30 includes multiple hole transport layers, one of the hole transport layers may be referred to as a hole injection layer. When the first functional layer includes a hole injection layer, the hole injection layer may be formed on the first electrode 20, which is the anode, and the hole transport layer may be formed on the hole injection layer.

[0021] (Hole injection layer) The first functional layer 30 may be a hole injection layer that injects holes. The hole injection layer also transports holes from the anode 20 side toward the light-emitting layer 40, 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, and Cu. ２ O, CoO, Cr ２ O ３ , CuAlS ２ Examples of suitable hole injection layer dispersions include nanoparticles, which are hole injection materials, for forming the first functional layer 30. The hole injection layer dispersion liquid containing nanoparticles contains a ligand having a functional group such as a carboxylic acid group, a thiol group, or an amino group. The hole injection layer of the first functional layer 30 may contain an organic ligand contained in the hole injection layer dispersion liquid (functional layer composition).

[0022] (Hole transport layer) The first functional 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 40. The hole transport layer can be formed on the first electrode 20, which is the anode, or on the hole injection layer, which is the first functional layer 30.

[0023] 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 40. 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 40 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).

[0024] [Light-emitting layer 40] The light-emitting layer 40 emits light through 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 40 is a quantum dot light-emitting layer that includes quantum dots (QDs: semiconductor nanoparticles) of any of the various colors as the light-emitting material.

[0025] The light-emitting layer 40 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.

[0026] The quantum dots (QDs) included in the light-emitting layer 40 may have, for example, a core structure, a core / shell structure, a core / shell / shell structure, or a shell structure with a continuously changing core / shell ratio. The shell may cover a portion of the core, but it is more preferable for the shell to completely cover the core. The core material of the quantum dots (QDs) may be, for example, a II-VI group semiconductor crystal such as MgS, MgSe, MgTe, CaS, CaSe, CaTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, PbS, PbSe, HgS, HgSe, or HgTe; a III-V group semiconductor crystal such as GaAs, GaP, InN, InAs, InP, or InSb; or Ga ３ S ２ , Ga ２ Se ３ , In ２ S ３ , In ２ Se ３ Crystals of III-VI group semiconductors such as CuInGaS, AgInGaS, CuInGaS, AgInGaZnS, CuInGaSe, AgInGaSe, etc., crystals of I-III-VI group semiconductors such as C and Si, crystals of IV group semiconductors such as CsPbI ３ , CsPbBr ３ , CsPbCl ３The shell material may be composed of a semiconductor crystal having a perovskite structure such as ZnSe or ZnSeTe. The shell material is preferably selected from the same material group as the core material, has a lattice constant close to that of the core material, and has a larger band gap than the core material. It is preferable to use, as the quantum dot (QD), for example, a material having a core / shell structure in which the core material is composed of InP and the shell material is composed of a metal sulfide (e.g., zinc sulfide (ZnS)), but this is not limited thereto. For example, ZnSe or ZnSeTe may be used as the core material, and these are preferably used in particular for the blue subpixel.

[0027] 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.

[0028] When the light-emitting layer 40 includes a matrix derived from a metal complex, the matrix may be, for example, ZnS (zinc sulfide), ZnTeS, or ZnMgS. ２ , MgS, Ga ２ S ３ , ZnGa ２ S ４ , MgGa ２ S ４ The matrix 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 40. ２ The light-emitting layer 40 may have an area of ​​10 nm or more and 100 nm or less. The light-emitting layer 40 may have a maximum thickness that is two times or less than the minimum thickness.

[0029] Furthermore, when the light-emitting layer 40 has, for example, a matrix derived from silicon oxide as the inorganic matrix, the matrix is ​​an oxide insulator. When the light-emitting layer 40 has a matrix derived from silicon oxide, a silicon oxide layer (not shown) containing the same type of silicon oxide as the silicon oxide may be formed between the light-emitting layer 40 and the first reaction product layer 51.

[0030] The light-emitting layer 40 may also include an inorganic matrix other than a matrix derived from a metal complex or silicon oxide. Examples of the inorganic matrix include a matrix of a silicate mineral such as mica, and a matrix of a ceramic (inorganic sintered body). Examples of the ceramic include alumina (Al ２ O ３ ), zirconia, barium titanate (BaTiO ３ ), hydroxide-based ceramics such as hydroxyapatite; carbonate-based ceramics; carbide-based ceramics such as silicon carbide (SiC); silicon nitride (Si ３ N ４ ) and other nitride ceramics; fluorite (CaF ２ ) and other halide-based ceramics; and phosphates.

[0031] The composition for the light-emitting layer used to form the light-emitting layer 40 contains a ligand and may contain silicon oxide, and therefore the light-emitting layer 40 may contain the ligand contained in the composition for the light-emitting layer or silicon oxide.

[0032] [First Reaction Product Layer] The first reaction product layer 51 is a layer that contains, as a first reaction product, a reaction product between the ligand contained in the light-emitting layer 40 and the base resin or photosensitizer contained in the resist agent composition, and is a layer formed from a resist layer (first resist layer).

[0033] (First Reaction Product) The first reaction product is a first reaction product produced by reacting a functional group possessed by the ligand with a functional group possessed by a base resin or a photosensitizer contained in the resist layer 80, which will be described later. The functional group possessed by the base resin or the photosensitizer is a functional group such as a carboxyl group or a hydroxyl group.

[0034] Examples of functional groups possessed by the ligand that contributes to the production of the first reaction product include polar groups such as a hydroxyl group, a carboxyl group, a thiol group, a xanthic acid group, an amine group, and a halogen atom. These functional groups are easily ionized by association with a proton or dissociation of a proton. The first reaction product is a reaction product obtained by reacting the functional group with functional groups possessed by the base resin and the photosensitizer, thereby etherifying, esterifying, amidating, converting to an acid halide, or halogenating the functional group.

[0035] The first reaction product includes an ether compound, sulfide compound, ester compound, thioester compound, amide compound, or acid halide derived from the ligand, and has a molecular structure derived from the ligand. The molecular structure derived from the ligand is a molecular structure other than the functional groups described above, and includes a saturated hydrocarbon group or an unsaturated hydrocarbon group having 1 to 40 carbon atoms, where the saturated hydrocarbon group or unsaturated hydrocarbon group may be linear or branched. The first reaction product is a compound in which the molecular structure derived from the precursor or the ligand is bonded to the base resin or the photosensitizer via an ether bond, a sulfide bond, an ester bond, a thioester bond, an amide bond, or a carbonyl bond.

[0036] The first reaction product layer 51 can reduce the number of ions in the regions between quantum dot (QD) particles by reacting and immobilizing easily ionizable functional groups possessed by ligands, etc., thereby reducing electrical conductivity and reducing leakage current.

[0037] (Ligand) When the light-emitting layer 40 includes a sulfide semiconductor matrix as the inorganic matrix, the first reaction product is a reaction product of a metal complex that serves as a ligand. The metal complex that serves as the ligand has functional groups such as a xanthogenic acid group, a thiocarboxylic acid group, and a thiourea group, and has an alkyl group having 1 to 5 carbon atoms as its molecular structure. This allows a matrix derived from the metal complex to be formed with lower energy. More specific examples of the ligands contained in the metal complex include xanthogenic acids such as methylxanthogenic acid, ethylxanthogenic acid, n-propylxanthogenic acid, and i-propylxanthogenic acid; thiocarboxylic acids such as methylthiocarboxylic acid, ethylthiocarboxylic acid, n-propylthiocarboxylic acid, and i-propylthiocarboxylic acid; N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea, and thioacetamide. Here, the functional groups possessed by the ligand are xanthogenate groups, thiocarboxylic acid groups, and thiourea groups, and the first reaction product is formed by reacting a xanthogenate ester bond, a thiocarboxylic acid ester bond, or a thioamide bond derived from these functional groups with a hydroxyl group or a carboxyl group possessed by the base resin or the photosensitizer. Here, the molecular structure derived from the metal complex is an alkyl group having 1 to 5 carbon atoms. The first reaction product may also include decomposition products obtained by thermal decomposition of bonds such as xanthogenate ester.

[0038] When the ligand that generates the first reaction product is a metal complex, the metal of the metal complex is, from the viewpoint of forming a metal sulfide semiconductor, preferably zinc (Zn), cadmium (Cd), lead (Pb), mercury (Hg), copper (Cu), indium (In), gallium (Ga), tin (Sn), potassium (K), magnesium (Mg), calcium (Ca), or barium (Ba), more preferably tin (Sn), magnesium (Mg), or zinc (Zn), and still more preferably zinc (Zn).

[0039] (Organic Ligand) When the light-emitting layer 40 does not contain a sulfide semiconductor matrix, the ligand is a ligand having a molecular structure selected from a saturated hydrocarbon group or an unsaturated hydrocarbon group having 1 to 40 carbon atoms and a functional group, where the saturated hydrocarbon group or unsaturated hydrocarbon group may be linear or branched. Examples of functional groups possessed by the ligand include thiol groups, hydroxyl groups, carboxyl groups, and amino groups, and one ligand may have two or more functional groups. Specific examples of the ligand include octylthiol, oleylamine, and oleic acid. The first reaction product produced by reaction with the ligand is formed by reacting ether bonds, amide bonds, or sulfide bonds derived from functional groups such as thiol groups, hydroxyl groups, carboxyl groups, amino groups, halogens, and xanthogenic acid with hydroxyl groups or carboxyl groups possessed by the base resin or photosensitizer. This ligand may be referred to as an organic ligand to distinguish it from the ligand when the light-emitting layer 40 contains a sulfide semiconductor matrix.

[0040] (Matrix Precursor) When the first reaction product is a reaction product with a matrix precursor, the first reaction product is a reaction product with a silicon oxide. Here, the silicon oxide may be selected from, for example, diphenylsilanediol, 3-mercaptopropyltrimethoxysilane, or 3-mercaptopropyltriethoxysilane. Other silicon oxides may include, for example, tetramethyl orthosilicate, tetraethyl orthosilicate, trimethoxyphenylsilane, etc.

[0041] The silicon oxide has at least one alkyl group (alkoxysilyl group) having 1 to 5 carbon atoms as its molecular structure, and has functional groups such as thiol groups, hydroxyl groups, and amino groups, and the first reaction product is formed by reacting ether bonds, amide bonds, and sulfide bonds derived from these functional groups with hydroxyl groups or carboxyl groups possessed by the base resin or photosensitizer. Here, the molecular structure derived from the silicon oxide contains an alkyl group having an alkoxysilyl group having an alkoxy group having 1 to 5 carbon atoms.

[0042] [Second Functional Layer] The light-emitting element 101 includes a second functional layer 60 between the second electrode 70 and the light-emitting layer 40. When the second electrode 70 is a cathode, the second functional layer 60 is an electron transport layer. The second functional layer 60, which is an electron transport layer, transports electrons from the second electrode 70, which is a cathode, toward the light-emitting layer 40. Although not shown, the second functional layer may be composed of multiple layers.

[0043] 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 40. Examples of electron transport materials include ZnO, ZnS, ZrO, MgZnO, AlZnO, and TiO. ２ Examples of such nanoparticles include those mentioned above. The electron transport layer-forming dispersion (functional layer composition) containing nanoparticles that are electron transport materials for forming the second functional layer 60 contains ligands on the surfaces of these nanoparticles, and the ligands are organic ligands. The second functional layer 60, which is an electron transport layer, may contain an organic ligand contained in the electron transport layer-forming dispersion. The ligands are the organic ligands described in the section on the first reaction product.

[0044] 2 is a cross-sectional view showing a schematic configuration of the light-emitting element 102 according to an embodiment of the present disclosure. The same members as those in the light-emitting element 101 are denoted by the same numbers, and descriptions thereof will be omitted.

[0045] The light-emitting element 102 has a functional layer 92 in which a first functional layer 30 which is a hole injection layer, a light-emitting layer 40, a first reaction product layer 51, a resist layer 80, and a second functional layer 60 which is an electron transport layer are stacked in this order between a first electrode 20 which is an anode and a second electrode 70 which is a cathode.

[0046] Like the first reaction product layer 51, the resist layer 80 is a layer containing a base resin for producing the first reaction product and a photosensitizer, and is a layer formed from a resist agent composition.

[0047] The thickness t1 of the first reaction product layer 51 is preferably within a range of 0.1 to 50 nm. In the first reaction product layer 51 having a thickness t1 within a range of 0.1 to 50 nm, the ligand contained in the light-emitting layer 40 is immobilized as a first reaction product. This prevents the light-emitting layer 40 from deteriorating over time due to the ligand, and thus prevents a decrease in luminous efficiency.

[0048] The first reaction product layer 51 may have a thickness t1 in the range of 0.1 to 50 nm, and may have a concentration gradient of the first reaction product from the front surface side of the light-emitting layer 40 toward the back surface side of the second electrode 70. In one embodiment, the first reaction product layer 51 is a layer formed by a reaction between a ligand diffused in the resist layer 80 and the base resin and photosensitizer contained in the resist layer, thereby generating and immobilizing the first reaction product.

[0049] The light emitting element 102 may have a resist layer 80 formed as a first resist layer between the first reaction product layer 51 and the second functional layer 60. A second reaction product layer, which will be described later, may be formed within the resist layer 80.

[0050] The thickness t2 of the resist layer 80 may be 0.1 to 50 nm, the same as that of the first reaction product layer 51, and the base resin and photosensitive agent contained in the resist layer 80 may be reacted with the organic ligand contained in the second functional layer 60 described below.

[0051] (Resist Agent Composition) The resist layer 80 is a layer formed from a resist agent composition containing a base resin and a photosensitizer. The resist layer 80 is a layer formed by leaving a portion of the resist agent composition coated on the substrate 10 on the substrate 10. The base resin has a functional group that reacts with the above-mentioned ligand or matrix precursor, or is a resin that generates the functional group upon exposure to light.

[0052] The functional groups of the base resin include carboxyl groups and hydroxyl groups. These functional groups, such as carboxyl groups and hydroxyl groups, of the base resin react with the functional groups of the precursor or ligand to produce an ether compound, a sulfide compound, an ester compound, a thioester compound, an amide compound, an acid halide, or a halide as a first reaction product.

[0053] The resist composition may be a positive resist composition or a negative resist composition. Whether the resist composition is a positive resist composition or a negative resist composition can be determined based on the types of base resin and photosensitizer.

[0054] Examples of base resins include resins that exhibit alkali-solubility due to the presence of water-soluble groups such as carboxyl groups or hydroxyl groups, and resins in which water-soluble groups such as carboxyl groups or hydroxyl groups are protected by protecting groups. Resins in which water-soluble groups are protected by protecting groups can generate these water-soluble groups and exhibit alkali-solubility by reacting with the photosensitizer described below. For example, resins having water-soluble groups such as carboxyl groups or hydroxyl groups include styrene-based resins such as poly(alkoxystyrene) resins, and resins that generate these water-soluble groups by reacting with the photosensitizer described below include acrylic resins such as polymethyl(meth)acrylate resin (PMMA) and polyethoxyethoxystyrene (PEES). These base resins can be used in combination with the photosensitizer described below to form positive resist compositions.

[0055] When the base resin is, for example, a resin in which water-soluble groups such as carboxyl groups and hydroxyl groups are not protected by protecting groups, it is preferable to use a photosensitizer that functions as a dissolution inhibitor, such as diazonaphthoquinone, which will be described later.

[0056] The base resin may be used in combination with a phenolic resin to form a negative resist composition or a reversal resist composition. A resist layer formed from the reversal resist composition can form a pattern as a positive resist that solubilizes at exposed locations, and after pattern formation and post-baking, the resist layer can function as a negative resist.

[0057] The base resin may be, for example, a phenolic resin such as a resol-type phenolic resin or a novolac-type phenolic resin. The resol-type phenolic resin is etherified by substituting the hydrogen atoms of the phenolic hydroxyl group and the hydroxymethyl group with an alkyl group. These resol-type phenolic resins and novolac-type phenolic resins may be used in combination, and may be used as a negative resist composition or a reversal resist composition by using a photosensitizer and a crosslinker described below in combination. The phenolic resin has functional groups such as hydroxyl groups.

[0058] Alternatively, the base resin may be a cyclized rubber such as cyclized isoprene or cyclized isobutylene.

[0059] The base resin may be a water-soluble thermoplastic resin, or may be a water-soluble resin that dissolves in pure water and alkaline aqueous solution. The water-soluble resin is preferably a block copolymer or graft copolymer containing two or more polymer units derived from different hydrophilic monomers, more preferably a graft copolymer. Here, each polymer unit may be a homopolymer or copolymer of a monomer unit derived from a water-soluble monomer. When the water-soluble resin is a block copolymer or 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.

[0060] The polymer units contained in the water-soluble resin include, as first polymer units, polymer units composed of monomer units having a functional group for reacting with a precursor or a ligand. Examples of such monomer units include monomer units derived from (meth)acrylic acid, (meth)acrylamide, N-vinylacetamide, polyvinyl alcohol, ethylene glycol, ethylenediamine, etc. When the monomer is (meth)acrylic acid, the (meth)acrylic acid may be contained in the first polymer units as an alkali metal salt or ammonium salt. Examples of monomer units derived from these monomers include vinyl alcohol monomer units, monomer units derived from (meth)acrylic acid, monomer units derived from (meth)acrylates, monomer units derived from (meth)acrylamide, and monomer units derived from N-vinylacetamide, with vinyl alcohol monomer units being preferred. Other examples of such monomer units include ethylene oxide units, ethyleneamine units, and propyleneamine units. The water-soluble monomer unit constituting the first polymer unit may be, for example, a monomer unit derived from a monomer having a hydrophilic group such as a carboxyl group, a hydroxyl group, an amino group, or an amide group, or may be a monomer unit that forms, upon polymerization, a hydrophilic main chain exemplified by a polyether chain such as polyethylene glycol, or a polyamine chain such as spermine or spermidine.

[0061] In order to enhance water solubility, the water-soluble resin preferably contains, as the second polymer unit, a polymer unit composed of a monomer unit derived from vinylpyrrolidone. The water-soluble resin is a block copolymer or graft copolymer of the second polymer unit composed of a monomer unit derived from vinylpyrrolidone and the first polymer unit composed of a monomer unit having a functional group for reacting with the precursor or ligand, and thereby it is possible to produce a reaction product between the water-soluble resin and the precursor or ligand while suitably controlling the film-forming properties.

[0062] In this specification, "(meth)acrylic acid" includes both "acrylic acid" and "methacrylic acid", and "(meth)acrylamide" includes both "acrylamide" and "methacrylamide".

[0063] 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 properties of the water-soluble resin can be controlled by adjusting the ratio of the molar amount 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.

[0064] 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.

[0065] 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 the water-soluble resin from being excessively removed by, for example, an alkaline aqueous solution. Furthermore, a PVA ratio less than 0.9 can prevent the water-soluble resin from remaining in excess. 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.

[0066] 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.

[0067] (Photosensitizer) The photosensitizer contained in the resist layer 80 may be preferably a diazoquinone compound, and the diazoquinone compound may be contained in the resist layer 80 as a product formed from the diazoquinone compound upon exposure. The diazoquinone compound forms indenecarboxylic acid upon exposure, and the carboxyl group of the indenecarboxylic acid can form a reaction product with a ligand or a precursor.

[0068] The photosensitizer contained in the resist composition is decomposed by, for example, light irradiation to release protons (H ＋ Any compound that generates a carboxylic acid group and an organic compound having an acid group such as a carboxylic acid group, a sulfonic acid group, or the like may be used. For example, organic compounds having a carboxylic acid group include indenecarboxylic acid, phthalic acid, and derivatives thereof. The photosensitizer may typically be a diazoquinone compound. Therefore, below, a positive photosensitizer will be described using a typical example of a diazoquinone compound. Examples of diazoquinone compounds include diazoquinones such as diazobenzoquinone (DBQ) and diazonaphthoquinone (DNQ), and derivatives thereof.

[0069] 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.

[0070] When the compound that forms an ester bond or an 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 reaction product layer in a developer before and after exposure. The conversion rate of the diazoquinone moiety is defined as the conversion rate of the hydroxyl group of the compound to an ester bond, or the conversion rate of the amino group of the compound to an amide bond, and is calculated by the following formula: (number of moles of diazoquinone moiety) / (number of moles of hydroxyl group and amino group of the compound before conversion to diazoquinone moiety) × 100

[0071] Examples of the derivatives of diazoquinone include diazoquinone sulfonic acid esters and diazoquinone sulfonic acid amides.

[0072] 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.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] The photosensitizer contained in the resist composition 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 by 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 polyphthalaldehyde such as polyphthalaldehyde having an oxime ether terminal.

[0077] When the photosensitizer is a diazoquinone compound, for example, indenecarboxylic acid generated from the diazoquinone compound may be decarboxylated by heating in the presence of an alkali compound such as imidazole, thereby suppressing the alkali solubility of the photosensitizer.

[0078] The photosensitizer may be a known photoacid generator, such as an onium salt-based acid generator or a bisazide compound.

[0079] Examples of onium salt acid generators include ammonium salts such as tetramethylammonium trifluoromethanesulfonate; iodonium salts such as diphenyliodonium trifluoromethanesulfonate; and sulfonium salts such as triphenylsulfonium trifluoromethanesulfonate.

[0080] Examples of the bisazide compound include 1,1'-biphenyl-4,4'-bisazide, 4,4'-methylidenebisazide, and 4,4'-oxybisazide.

[0081] The resist layer 80 may also contain a crosslinking agent. The crosslinking agent may be a crosslinking agent that crosslinks the base resin by the acid generated when the photosensitive agent contained in the resist composition is exposed to light. Examples of the crosslinking agent include melamine compounds, guanamine compounds, glycoluril compounds, and urea compounds substituted with hydroxymethylene groups, etc.; epoxy compounds, thioepoxy compounds, and isocyanate compounds; and compounds having unsaturated double bond groups such as alkenyl ether groups. The crosslinking agent content in the resist composition is not limited, but may be, for example, more than 0 parts by mass, preferably 100 parts by mass or less, and more preferably 50 parts by mass or less, based on 100 parts by mass of the total of the base resin and the diazoquinone compound.

[0082] The resist composition may also contain a crosslinking aid such as a photobase generator such as amidine or guanidine, or an alkaline compound such as diethylamine.

[0083] In addition, the resist composition may contain, as additives, for example, a photosensitizer such as acetophenone, a chemical sensitizer, a filler, a colorant, a stabilizer such as an antioxidant, a surfactant such as a leveling agent, an antifoaming agent, a dispersant, and a quencher.

[0084] 3 is a cross-sectional view showing a schematic configuration of the light-emitting element 103 according to an embodiment of the present disclosure. The same members as those in the light-emitting element 101 are denoted by the same numbers, and their description will be omitted.

[0085] The light-emitting element 103 has a functional layer 93 in which a first functional layer 30 which is a hole injection layer, a light-emitting layer 40, a first reaction product layer 51, a second reaction product layer 52, and a second functional layer 60 which is an electron transport layer are stacked in this order between a first electrode 20 which is an anode and a second electrode 70 which is a cathode.

[0086] For convenience, in this specification, the term "first reaction product layer" refers to a reaction product layer in contact with the light-emitting layer, and the term "second reaction product layer" refers to a reaction product layer in contact with a functional layer other than the light-emitting layer 40. Both the first reaction product layer and the second reaction product layer contain reaction products having molecular structures derived from ligands or matrix precursors contained in the dispersion liquid for forming the light-emitting layer or the functional layer. The first reaction product layer and the second reaction product layer may contain the same type of reaction product, or may contain different types of reaction products.

[0087] The light-emitting element 103 comprises a first reaction product layer 51 in contact with the surface of the light-emitting layer 40, and a second reaction product layer 52 in contact with the back surface of the second functional layer 60 (the surface opposite the surface of the light-emitting layer 40). The second reaction product layer 52 contains a reaction product having a molecular structure derived from a ligand contained in the second functional layer 60, which is an electron transport layer. This allows the ligand contained in the dispersion liquid for forming the second functional layer 60 to remain in the second functional layer 60, preventing a decrease in the luminous efficiency of the light-emitting element over time.

[0088] The second reaction product layer 52 included in the light-emitting element 103 may be a layer formed by reaction of a ligand contained in a dispersion liquid for forming the second functional layer 60 in the resist layer 80 included in the light-emitting element 102 shown in Fig. 2. Alternatively, the second reaction product layer 52 may be a reaction product layer formed by reaction of a ligand contained in a dispersion liquid for forming the second functional layer 60 in the resist layer 80 as a second resist layer that is separately provided on the first reaction product layer 51.

[0089] 4 is a cross-sectional view showing a schematic configuration of a light-emitting element 104 according to an embodiment of the present disclosure. The light-emitting element 104 includes a functional layer 94 in which a first functional layer 30 serving as a hole injection layer, a second reaction product layer 53, a light-emitting layer 40, and a second functional 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.

[0090] The light-emitting element 104 includes a second reaction product layer 53 in contact with the back surface of the light-emitting layer 40, and the second reaction product layer 53 is formed from the first second resist layer. By including the second reaction product layer 53, the light-emitting element 104 is prevented from decreasing in luminous efficiency over time due to the ligand or precursor. The light-emitting element 104 may also include a second reaction product layer (not shown) between the second reaction product layer 53 and the first functional layer 30. When the light-emitting element 104 includes the second reaction product layer, the second reaction product layer contains a reaction product having a molecular structure derived from the organic ligand contained in the first functional layer 30, which is a hole transport layer.

[0091] 5 is a cross-sectional view showing a schematic configuration of a light-emitting element 105 according to an embodiment of the present disclosure. The light-emitting element 105 includes a functional layer 95 including a first functional layer 30, a light-emitting layer 40, a first reaction product layer 51 surrounding the outer peripheral end face of the light-emitting layer 40, and a second functional layer 60 between a first electrode 20 serving as an anode and a second electrode 70 serving as a cathode.

[0092] In the light-emitting element 105, the second reaction product layer 54 may contain a first reaction product. The second reaction product layer 54 also contains a second reaction product derived from the ligand of the first functional layer 30. The light-emitting element 105 may also include a second reaction product layer (not shown) between the second reaction product layer 54 and the second functional layer 60.

[0093] 6 is a cross-sectional view showing a schematic configuration of a light-emitting element 106 according to an embodiment of the present disclosure. The light-emitting element 106 includes a functional layer 96 in which a first functional layer 30 serving as a hole injection layer, a second reaction product layer 53, a light-emitting layer 40, a first reaction product layer 51, and a second functional 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.

[0094] In the light-emitting element 106, first reaction product layers are formed on the front and back surfaces of the light-emitting layer 40. These first reaction product layers immobilize the ligand contained in the light-emitting layer 40, preventing a decrease in the luminous efficiency of the light-emitting element over time due to the ligand or precursor.

[0095] The light-emitting element 106 may have a second reaction product layer (not shown) between the first functional layer 30 and the second reaction product layer 53, or may have a second reaction product layer (not shown) between the first reaction product layer 51 and the second functional layer 60.

[0096] 7 is a cross-sectional view showing a schematic configuration of a light-emitting element 107 according to an embodiment of the present disclosure. The light-emitting element 107 includes a functional layer 97 between a first electrode 20 serving as an anode and a second electrode 70 serving as a cathode, the functional layer 97 including a first functional layer 30 serving as a hole injection layer, a second reaction product layer 53, a light-emitting layer 40, a second reaction product layer 54 surrounding the light-emitting layer 40, the first reaction product layer 51, and a second functional layer 60 serving as an electron transport layer. At the bottom surface of a bank described below, the second reaction product layer 54 surrounding the light-emitting layer 40 constitutes a part of the light-emitting element.

[0097] The light-emitting element 107 may include a second reaction product layer (not shown) between the first functional layer 30 and the second reaction product layer 53, or may include a second reaction product layer (not shown) between the first reaction product layer 51 and the second functional layer 60. The light-emitting element 107 may include a second reaction product layer (not shown) formed between the second reaction product layer 53 and the first functional layer 30. In the light-emitting element 107, reaction product layers are formed on the front, back, and outer peripheral end surface of the light-emitting layer 40, thereby immobilizing the ligand or precursor contained in the light-emitting layer composition for forming the light-emitting layer 40.

[0098] <Display Device> FIG. 8 is a plan view showing a schematic configuration of the display device 200. As shown in FIG.

[0099] 8 , the display device 200 includes a frame region NDA and a display region DA. The display region 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.

[0100] 9 , display device 200 has red sub-pixel RSP, blue sub-pixel BSP, and green sub-pixel GSP as light-emitting regions in display area DA, where red sub-pixel RSP has light-emitting element 110R that emits red light, blue sub-pixel BSP has light-emitting element 110B that emits blue light, and green sub-pixel GSP has light-emitting element 110G that emits green light. Display area DA of display device 200 has banks formed of resist layer 80 surrounding each sub-pixel as non-light-emitting regions.

[0101] 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 functional layer, a light-emitting layer, a second functional layer, and at least one first reaction product layer or second reaction product layer illustrated in FIGS. 1 to 7 are stacked between the first electrode 20 and the second electrode 70, and the first reaction product layer is in contact with at least a portion of the light-emitting layer.

[0102] 9, the display device 200 includes, on a substrate 151, 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, and a bank formed from a resist layer 80, a sealing layer 180, and a functional film 185, in this order from the substrate 151 side. Note that, as shown in FIG. 8, a substrate including, on the substrate 151, a barrier layer 152, a thin-film transistor layer 170 including a transistor TR, and a plurality of first electrodes 20, in this order from the substrate 151 side, is referred to as a substrate (active matrix substrate) 10.

[0103] 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.

[0104] The barrier layer 152 is a layer that prevents foreign substances such as water and oxygen from penetrating into 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 composed of, for example, 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 reaction product 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.

[0105] 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.

[0106] 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.

[0107] The gate electrode G and the source electrode S and drain electrode D can be formed 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.

[0108] 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.

[0109] The first electrodes 20 of the light emitting elements 110R, 110B, and 110G are provided above the planarization film 174, and banks are provided that are formed from an insulating resist layer 80 that covers the edges of each of the plurality of first electrodes 20. The banks constitute non-light emitting areas in the display area DA, and can be formed by patterning the resist layer by photolithography.

[0110] 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 the light-emitting elements 110R, 110B, and 110G. The display device 200 includes a reaction product layer in each of the functional layers 90R, 90B, and 90G, thereby preventing moisture that has permeated the sealing layer 180 from penetrating the light-emitting layers.

[0111] The functional film 185 is, for example, a film having at least one of an optical compensation function and a protection function.

[0112] <Method for manufacturing light-emitting element> A method for manufacturing a light-emitting element and a display device according to an embodiment of the present disclosure will be described with reference to Figures 10 to 25. As shown in Figures 10 to 25, the method for manufacturing a light-emitting element and a display device according to an embodiment of the present disclosure includes the steps of (i) exposing a resist layer formed on a functional layer to form a second reaction product layer, (ii) forming a light-emitting layer on the second reaction product layer of the resist layer after developing a pattern, and (iii) peeling and developing the resist layer to form a light-emitting layer, thereby forming a plurality of light-emitting layers, and (iv) forming a resist layer on the plurality of light-emitting layers and exposing the resist layer to form a first reaction product layer.

[0113] 10 , a first electrode 20 is formed on a substrate 10 by a general electrode formation method. The first electrode 20 may be made of an electrode material that reflects visible light, and the first electrode 20 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 20 may be patterned by, but is not limited to, photolithography or an inkjet method.

[0114] The hole injection layer, which is the first functional layer 30 formed on the substrate 10, is formed from a hole injection layer-forming dispersion liquid containing the hole injection material such as NiO described above and a polar solvent such as water, ethanol, or dimethyl sulfoxide, and the hole injection material has a ligand. Here, the ligand is the organic ligand described in the section on the first reaction product.

[0115] 10 is formed from a resist composition containing the above-mentioned base resin and photosensitizer. The resist composition contains the above-mentioned base resin and photosensitizer. The base resin is as described in the section on the reaction product layer included in the light-emitting element.

[0116] The resist composition may contain, as solid content, 100 parts by mass of the base resin and 1 to 500 parts by mass of the photosensitizer.

[0117] An example of forming a resist layer and a reaction product layer using a positive resist composition will be described below.

[0118] The resist composition is applied to the sub-pixels of the plurality of light-emitting elements collectively by dip coating or spin coating, thereby providing the second reaction product layer 53. Thereafter, the second reaction product layer 53 may be heated (pre-baked) at a temperature in the range of 80 to 150° C., for example. The resist composition for forming the second reaction product layer 53 is not limited to being applied to the sub-pixels collectively, and may be applied separately to each sub-pixel by, for example, an inkjet method or the like.

[0119] 10, a photomask 300 having a desired pattern is used to expose the resist layer 81 (second resist layer), thereby forming a second reaction product layer 53B on the first functional layer 30. Examples of exposure conditions for exposing the second reaction product layer 53 include ultraviolet light with a wavelength of approximately 150 to 450 nm, an electron beam, and the like. In consideration of the reactivity of the ligand or precursor, irradiation with ultraviolet light with a wavelength of 150 to 330 nm is preferred. The ultraviolet light may be g-line (wavelength 436 nm), h-line (wavelength 405 nm), or i-line (wavelength 365 nm) emitted from a high-pressure mercury lamp, but is preferably an excimer laser (wavelength 150 to 248 nm). For example, the bond energy of the carbon-carbon bond in the molecular structure of the ligand or precursor is 366 kJmol －１ The resist layer 81 may be irradiated with the above energy, and the exposure amount is not limited to, for example, 1 mJ / cm 2 in consideration of the bonding energy. ２ ~1000mJ / cm ２ It can be adjusted within the range.

[0120] Furthermore, the resist layer 81 exposed under the above-mentioned exposure conditions may be post-baked at a heating condition of 40 to 300° C. to promote the reaction between the base resin or the photosensitizer and the organic ligand.

[0121] When the reaction product contained in the second reaction product layer 53B is a reaction product of a base resin and the above-mentioned organic ligand, the reaction product may be a compound represented by the following formula (1). In formula (1), the main chain is the base resin, and may be a block copolymer or a graft polymer having side chains. In formula (1), X １ is an ether bond, an ester bond, an amide bond, or a carbonyl bond, and is formed by a reaction between a hydroxyl group or a carboxyl group of the base resin and a functional group of the organic ligand. When the base resin contains a phenolic resin, X １ may be bonded to the main chain of the base resin via a phenyl group. １is a molecular structure derived from a ligand, and is a molecular structure selected from saturated hydrocarbon groups and unsaturated hydrocarbon groups having 1 to 40 carbon atoms, and the saturated hydrocarbon group and unsaturated hydrocarbon group may be linear or branched. １ -R １ The number of groups is, but is not limited to, one; １ -R １ It may have a group.

[0122] Furthermore, when the reaction product contained in the second reaction product layer 53B is a reaction product of an organic ligand and a photosensitizer, the reaction product may be a reaction product of indenecarboxylic acid represented by the following formula (2).

[0123]

[0124] In formula (2), X １ R is an ether bond, an ester bond, an amide bond, or a carbonyl bond formed by the reaction of a carboxyl group of an indenecarboxylic acid with a functional group of an organic ligand. １ is a molecular structure derived from the ligand, and is the same as formula (1), so its explanation will be omitted.

[0125] By generating a second reaction product in the resist layer 81, an ether bond, an ester bond, an amide bond, or a carbonyl bond is generated from the functional group that is easily ionized by association with a proton or dissociation of a proton, and the ligand can be immobilized to the base resin or the photosensitizer.

[0126] 11 is a diagram illustrating an outline of a process of washing the resist layer 81 with a developer after forming the second reaction product layer 53B. After forming the second reaction product layer 53B, the exposed portions of the resist layer 81 are washed with an alkaline aqueous developer, thereby developing a desired pattern in the second reaction product layer 53B. The desired pattern can be developed by, for example, immersing the second reaction product layer 53 in a beaker (not shown) containing the developer. The developer can be supplied to the second reaction product layer 53 by spraying the developer using a spray nozzle or the like.

[0127] 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).

[0128] After development, the second reaction product layer 53 formed on the first functional layer 30 may be dried by heating at a temperature of, for example, 50 to 150°C.

[0129] 12 is a diagram illustrating an outline of the process of forming a light-emitting layer 40B on the second reaction product layer 53B. The light-emitting layer 40B can be formed by applying a composition containing a light-emitting material onto the second reaction product layer 53B. The light-emitting layer 40B is no different from the light-emitting layer 40B' provided on the unexposed areas of the second reaction product layer 53B, except that the light-emitting layer 40B is formed on the exposed areas of the second reaction product layer 53B. In the process of forming the light-emitting layer, it is sufficient that the light-emitting layer 40B is formed, and the light-emitting layer 40B' is not necessarily formed.

[0130] The light-emitting layer can be formed by applying a composition for the light-emitting layer to each subpixel separately by spin coating, inkjet printing, etc. The quantum dot dispersion liquid contains a solvent such as hexane, toluene, or phenylcyclohexane, and may be mixed with a dispersing material such as thiol or amine.

[0131] 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.

[0132] 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. As a result, the dispersion contains, as a precursor, a metal complex in which xanthogenic acid, thiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea, or thioacetamide is coordinated to a metal atom.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] A dispersion of quantum dots in a polar solvent is applied onto the second reaction product layer 53, and the laminate is heated to 80°C to 500°C to form a light-emitting layer containing quantum dots with a shell of sulfide semiconductor as an inorganic ligand.

[0137] 13 is a diagram illustrating an outline of the process of peeling and developing the light-emitting layer 40B by peeling off the resist layer 81 other than the pattern provided on the reaction product layer 53. In the peeling and developing process, the light-emitting layer 40B' is peeled off from the substrate 10 by a developer together with unexposed areas of the resist layer 81. As a result, the light-emitting layer 40B is developed into the desired pattern on the second reaction product layer 53.

[0138] 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 reaction product layer described above, and examples of such organic solvents include 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 second reaction product layer 53 containing the positive-type photosensitizer can be successfully peeled off together with the light-emitting layer 40B', and the light-emitting layer 40B can be developed to have a desired pattern.

[0139] The developer may be supplied to the light-emitting layer 40B by immersing it in a beaker (developer tank) containing the developer, or by spraying the developer using a spray nozzle or the like.

[0140] After the peel-off development process, the light-emitting layer 40B and the second reaction product layer 53B formed in the desired pattern may be post-baked under the heating conditions described above to form a first reaction product layer (not shown) on the back surface of the light-emitting layer 40B.

[0141] 13 , since the second reaction product layer 53B is formed after peel-off development, even if an organic ligand is contained in the dispersion liquid for forming the first functional layer 30, the second reaction product layer 53B can inactivate the organic ligand. Furthermore, the organic ligand can be prevented from penetrating into the light-emitting layer 40B formed in a later step.

[0142] 14 is a diagram illustrating an outline of the step of forming second reaction product layer 53R (step of forming a second second reaction product layer). Second reaction product layer 53R is formed by exposing resist layer 82 to light through photomask 301 having a pattern different from that of photomask 300.

[0143] The resist composition for forming the second reaction product layer 53R may have the same composition as the resist composition for forming the second reaction product layer 53B, or may have a different composition, and may be designed appropriately depending on the type of ligand or precursor contained in the light-emitting layer composition for forming the light-emitting layer 40R.

[0144] The method of applying the resist composition to form the second reaction product layer 53R, as well as the exposure conditions and heating conditions, are the same as those in the process for forming the second reaction product layer 53B, and therefore will not be described here.

[0145] 15 is a diagram illustrating an outline of the step of forming a light-emitting layer 40R on the second reaction product layer 53R (a step of forming a second light-emitting layer). The light-emitting layer 40R is formed by applying a composition containing a light-emitting material that emits red light onto the second reaction product layer 53R. The light-emitting layer 40R' is no different from the light-emitting layer 40R except that it is formed in the unexposed areas of the resist layer 82.

[0146] 16 is a diagram illustrating an outline of the step of peeling and developing the light-emitting layer 40R (second peeling and developing step). In the second peeling and developing step, the unexposed portions of the resist layer 82 are peeled off together with the light-emitting layer 40R', while leaving the second reaction product layer 53R covered by the light-emitting layer 40R. This allows the light-emitting layer 40R to be developed into a desired pattern.

[0147] 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.

[0148] 17 is a cross-sectional view showing an outline of the step of forming second reaction product layer 53G (step of forming a third second reaction product layer). Second reaction product layer 53G is formed by exposing resist layer 83 through photomask 302 having a pattern different from photomasks 300 and 301. The conditions for exposure are the same as those for the first exposure step, and therefore a description thereof will be omitted. The composition for forming second reaction product layer 53G may have the same composition as the composition for forming second reaction product layers 53B and 53R, or may have a different composition.

[0149] 18 is a diagram illustrating an outline of the process of forming a light-emitting layer 40G on the second reaction product layer 53G (the process of forming a third light-emitting layer). The light-emitting layer 40G is formed by applying a dispersion containing a light-emitting material that emits green light onto the second reaction product layer 53G. The preparation of the dispersion containing the light-emitting material for forming the light-emitting layer 40G is similar to the preparation of the dispersion containing the light-emitting material for forming the light-emitting layer 40B, and therefore a description thereof will be omitted. Furthermore, the light-emitting layer 40G' is no different from the light-emitting layer 40G except that it is not formed on the second reaction product layer 53G.

[0150] 19 is a diagram illustrating an outline of the step of peeling and developing the light-emitting layer 40R (third peeling and developing step). In the third peeling and developing step, the unexposed portions of the resist layer 83 are peeled off together with the light-emitting layer 40R', while leaving the second reaction product layer 53G covered by the light-emitting layer 40G. This allows the light-emitting layer 40G to be developed into a desired pattern.

[0151] The developer used in the third peel-and-develop process and the peel-and-develop conditions are the same as those in the first peel-and-develop process, and therefore a description thereof will be omitted.

[0152] FIG. 20 is a diagram for explaining an outline of a process for forming a first reaction product layer 51 on the light-emitting layers 40R, 40B, and 40G formed on the substrate 10. In FIG.

[0153] A resist composition is applied to the light-emitting layers 40R, 40B, and 40G, and the resulting resist layer 84 (first resist layer) is exposed to light, thereby forming a first reaction product layer 51 containing a reaction product (first reaction product) on the surface of the light-emitting layers 40R, 40B, and 40G. The exposure conditions for forming the first reaction product layer 51 are the same as those for forming the second reaction product layer 53R described above, and therefore a description thereof will be omitted. Note that a first reaction product layer (not shown) may be formed on the back surface of the light-emitting layers 40R, 40B, and 40G by post-baking the light-emitting layers 40R, 40B, and 40G and the second reaction product layers 53R, 53B, and 53G under the heating conditions used to form the second reaction product layer 53R described above.

[0154] When the reaction product contained in the first reaction product layer 51 is a reaction product of a base resin and a ligand or a precursor, the reaction product may be a compound represented by the following formula (1'). In formula (1'), the main chain is the base resin, and may be a block copolymer or a graft polymer having side chains. In formula (1'), X ２ is an ether bond, a sulfide bond, an ester bond, a thioester bond, an amide bond, or a carbonyl bond formed by the reaction of a hydroxyl group or a carboxyl group of the base resin with a functional group of the ligand. When the base resin contains a phenolic resin, X ２ may be bonded to the main chain of the base resin via a phenyl group. ２ R may be a xanthate ester bond, a thiocarboxylate ester bond, or a thioamide bond. ２ is a molecular structure derived from the precursor described in the [First Reaction Product Layer] section, and is selected from alkyl groups having 1 to 40 carbon atoms; X ２ is a carbonyl group or a single bond, R ２ is a halogen. ２ may be a molecular structure derived from silicon oxide explained in the section [First reaction product layer]. ２ -R ２ The number of groups is, but is not limited to, one; ２ -R２ It may have a group.

[0155]

[0156] Furthermore, when the reaction product contained in the first reaction product layer 51 is a reaction product between a precursor and a photosensitizer, the reaction product may be a reaction product of indenecarboxylic acid represented by the following formula (2').

[0157]

[0158] In formula (2'), X ２ is an ether bond, a sulfide bond, an ester bond, a thioester bond, an amide bond, or a carbonyl bond formed by a reaction between a carboxyl group of the indenecarboxylic acid and a functional group of the ligand or precursor. ２ R may be a xanthate ester bond, a thiocarboxylate ester bond, or a thioamide bond. ２ is a molecular structure derived from the precursor, and is the same as formula (1'), so the explanation thereof will be omitted.

[0159] The first reaction product layer 51 may be formed by reacting the base resin with the ligand contained in the first functional layer 30 within the resist layer 84. This allows a functional group that is easily ionized by association with a proton or dissociation of a proton to react with the base resin or the photosensitizer, thereby forming an ether bond, an ester bond, an amide bond, or a carbonyl bond, and immobilizing the ligand to the base resin or the photosensitizer.

[0160] In Figure 21, the resist layer 84 is removed by washing after the first reaction product layer 51 is formed, but it may also be left as a resist layer for fixing the ligand contained in the second functional layer 60 described below.

[0161] 22, the composition used to form the second functional layer 60, which is an electron transport layer, may be any composition containing the electron transport material described above, and the composition contains the ligand described in the section on the first reaction product. The composition may be applied to the sub-pixels of the plurality of light-emitting elements collectively by spin coating, dip coating, or the like on the substrate 10 on which the light-emitting layers 40R, 40B, and 40G have been formed, or may be applied separately to each sub-pixel by inkjet printing or the like.

[0162] By exposing the second functional layer 60 shown in Figure 22 under the above-mentioned exposure conditions or post-baking under the above-mentioned heating conditions, a second reaction product layer (not shown) may be formed on the back surface of the second functional layer 60, which contains as a second reaction product a reaction product between the organic ligand contained in the second functional layer 60 and the base resin and photosensitive agent contained in the resist layer 84.

[0163] The second electrode 70 shown in FIG. 23 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.

[0164] 23 includes light-emitting elements 120R, 120B, and 120G that form a light-emitting region HR, and includes a non-light-emitting region NHR between the light-emitting elements. The widths of the light-emitting elements 120R, 120B, and 120G that form the light-emitting region and the width of the non-light-emitting region NHR can be adjusted by the pattern of a photomask used when forming the first reaction product layer 51 and the second reaction product layer 53.

[0165] Furthermore, the pattern shape and timing of each exposure for forming a reaction product layer may be designed depending on whether the resist layer is a positive resist layer or a negative resist layer. For example, in the case of a negative resist layer, the negative resist composition may be applied to the light-emitting layer or the functional layer, and then a cleaning liquid (e.g., a developer) may be supplied before exposure to adjust the film thickness of the resist layer, and then the negative resist layer may be exposed to generate a reaction product.

[0166] Furthermore, for example, when the resist layer is a positive resist layer formed from a reversal resist composition, the method may include the steps of exposing the positive resist layer to a predetermined pattern in advance, heating the exposed positive resist layer, exposing the entire surface of the heated positive resist layer, and supplying a developer to the positive resist layer whose entire surface has been exposed, thereby developing the predetermined pattern in the positive resist layer. Here, the reversal resist composition may include a diazonaphthoquinone compound and an alkali compound. As a result, indenecarboxylic acid produced in the step of exposing to a predetermined pattern may be heated in the heating step to eliminate carbonic acid, and the resulting indene may act as a dissolution inhibitor.

[0167] Display Device 220 According to an Embodiment of the Present Disclosure The display device according to an embodiment of the present disclosure is not limited to the above-described embodiment. For example, as shown in FIG. 24 , a display device 220 according to an embodiment of the present disclosure includes a first bank formed from a resist layer 81 in a non-light-emitting region NHR between light-emitting elements 120R, 120B, and 120G, where a first reaction product layer 51 is formed in a recess formed by the first bank. The first bank may be formed by using a reversal resist composition or a negative resist composition to form the resist layer 81, and patterning the resist layer 81 to form the first bank during the exposure process shown in FIG. 10 . The bank formed from the resist layer 81 included in the display device 220 is a bank formed after the first functional layer 30 is formed, and such a bank may be referred to as a post-established bank.

[0168] Display Device 230 According to an Embodiment of the Present Disclosure The display device according to an embodiment of the present disclosure is not limited to the above-described embodiment. For example, as shown in FIG. 25 , a display device 230 according to an embodiment of the present disclosure includes a bank (first bank) formed from a resist layer 80 in a non-light-emitting region NHR between light-emitting elements 120R, 120B, and 120G, and further includes a second bank formed from a resist layer 84. The bank may be formed by using a reversal resist composition or a negative resist composition to form the resist layer 84, and patterning the resist layer 84 to form the second bank during the exposure process shown in FIG. 10 . The bank formed from the resist layer 84 included in the display device 230 is a bank formed after the second functional layer 60 is formed, and a bank formed from the resist layer 84 on top of the bank formed from the resist layer 80 in this manner may be referred to as a double bank.

[0169] 26 , a display device 240 according to an embodiment of the present disclosure is not limited to the above embodiment. For example, as shown in FIG. 26 , a display device 240 according to an embodiment includes light-emitting elements 121R, 121B, and 121G, and the light-emitting elements 121R, 121B, and 121G include first reaction product layers 51R, 51B, and 51G corresponding to the light-emitting layers 40R, 40B, and 40G, respectively. The first reaction product layers 51R, 51B, and 51G may contain different reaction products depending on the types of ligands or precursors contained in the light-emitting layers 40R, 40B, and 40G.

[0170] 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.

[0171] 10 Substrate 20 First electrode 30 First functional layer 40, 40R, 40B, 40G Light-emitting layer 51, 52, 53, 54 Reaction product layer (first and second reaction product layer) 60 Second functional layer 70 Second electrode 80, 81, 82, 83, 84 Resist layer (bank) 110R, 120R, 121R Light-emitting element (light-emitting element that emits red light) 110B, 120B, 121B Light-emitting element (light-emitting element that emits blue light) 110G, 120G, 121G Light-emitting element (light-emitting element that emits green light) 200, 210, 220, 230, 240 Display device HR Light-emitting region NHR Non-light-emitting region

Claims

1. A light-emitting element comprising a first electrode and a second electrode, a light-emitting layer between the first and second electrodes, and at least one first reaction product layer provided on at least one surface selected from the front surface, back surface, and outer peripheral edge surface of the light-emitting layer, wherein the first reaction product layer contains a first reaction product that is a reaction product of a ligand with a base resin and a photosensitizer, and the first reaction product has a molecular structure derived from the ligand.

2. The light-emitting device of claim 1, wherein the ligand is an organic ligand.

3. A light-emitting element as described in claim 1 or 2, comprising at least one functional layer between the first and second electrodes, the functional layer being formed so as to face at least one of the front and back surfaces of the light-emitting layer, with the first reaction product layer sandwiched therebetween.

4. A light-emitting element as described in claim 3, comprising at least one resist layer, the first reaction product layer being positioned between the resist layer and the functional layer, and the resist layer being formed so as to cover at least one surface selected from the front surface, back surface, and outer peripheral end surface of the light-emitting layer via the first reaction product layer.

5. The light-emitting element according to claim 4, further comprising a second reaction product layer, the second reaction product layer being provided on a surface of the functional layer facing the light-emitting layer.

6. The light-emitting element according to claim 5, wherein the resist layer is formed between the first reaction product layer and the second reaction product layer.

7. A light-emitting element according to any one of claims 1 to 6, comprising a plurality of first reaction product layers, any one of the plurality of first reaction product layers being provided on either the front or back surface of the light-emitting layer.

8. The light-emitting device according to claim 7, wherein one of the plurality of first reaction product layers is provided on the outer peripheral end surface of the light-emitting layer.

9. The light-emitting element according to any one of claims 3 to 8, wherein the functional layer facing the front surface of the light-emitting layer is a hole transport layer, and the functional layer facing the back surface of the light-emitting layer is an electron transport layer.

10. A light-emitting element according to any one of claims 4 to 6, wherein a first bank surrounding the light-emitting region is formed in a non-light-emitting region surrounding the light-emitting region of the light-emitting element, the first bank being formed from the resist layer, and the first reaction product layer being formed in a recess formed by the first bank.

11. The light-emitting element according to claim 10, further comprising a second bank in the non-light-emitting region that surrounds the light-emitting region, the first bank being formed on the second bank.

12. The light-emitting device according to any one of claims 1 to 11, wherein the light-emitting layer comprises an inorganic matrix.

13. The light-emitting element according to claim 12, wherein the inorganic matrix contains silicon oxide, and a silicon oxide layer containing the same type of silicon oxide as the silicon oxide is formed between the light-emitting layer and the first reaction product layer.

14. The light-emitting device according to any one of claims 1 to 13, wherein the base resin is selected from a water-soluble resin, a polymethyl(meth)acrylate resin, and a poly(alkoxystyrene) resin, and the photosensitizer is selected from a diazonaphthoquinone compound, a photoacid generator, or a photobase generator.

15. The light-emitting device according to claim 14, wherein the base resin further comprises a phenolic resin.

16. The light-emitting element according to any one of claims 1 to 12, wherein the base resin contains a cyclized rubber, and the photosensitizer contains a bisazide compound.

17. The light-emitting element according to claim 14 or 15, wherein the water-soluble resin includes a graft copolymer or a block copolymer, and the graft copolymer and the block copolymer have at least two polymer units derived from different hydrophilic monomers.

18. The light-emitting element according to claim 17, wherein the graft copolymer or block copolymer is a copolymer of a polymer unit in which a vinyl alcohol monomer unit is polymerized and a polymer unit in which an N-vinylpyrrolidone monomer unit is polymerized.

19. A light-emitting element described in any one of claims 1 to 18, wherein the first reaction product is a compound selected from the group consisting of thioester compounds, amide compounds, ester compounds, acid halides, and halides having the molecular structure, and the molecular structure is selected from a linear or branched saturated hydrocarbon group having 1 to 40 carbon atoms or an unsaturated hydrocarbon group.

20. A display device having a display area in which a plurality of light-emitting elements are formed on a substrate, each of the plurality of light-emitting elements being a light-emitting element according to any one of claims 1 to 19.

21. The display device according to claim 20, wherein each of the plurality of light-emitting elements has the first reaction product layer provided on the surface of the light-emitting layer, and the first reaction products contained in each of the first reaction product layers are different types of reaction products.

22. A method for manufacturing a light-emitting device comprising: a light-emitting layer between first and second electrodes; and a first reaction product layer provided on at least one surface of the light-emitting layer; wherein a light-emitting layer composition for forming the light-emitting layer comprises quantum dots and a ligand, and a resist composition comprises a base resin and a photosensitizer; the method includes the steps of: forming the light-emitting layer by applying the light-emitting layer composition onto the first or second electrode; forming a resist layer by applying the resist composition onto the light-emitting layer; and forming a first reaction product layer on the resist layer provided on either surface of the light-emitting layer while forming a pattern in the resist layer by exposing at least a portion of the resist layer; and wherein in the step of forming the first reaction product layer, a first reaction product having a molecular structure derived from the ligand is produced by reacting the ligand with the base resin and the photosensitizer.

23. The method for producing a light-emitting device according to claim 22, wherein the ligand is an organic ligand.

24. The method for manufacturing a light-emitting element according to claim 22 or 23, wherein in the step of forming the first reaction product layer, at least a portion of the resist layer is left within the pattern during the exposure.

25. A method for manufacturing a light-emitting element described in any one of claims 22 to 24, wherein in the step of forming the first reaction product layer, the first reaction product layer is formed by applying energy within the pattern during the exposure under exposure conditions of a wavelength of 330 nm or less.

26. A method for manufacturing a light-emitting element comprising a plurality of light-emitting elements by repeating each step included in the method for manufacturing a light-emitting element according to any one of claims 22 to 25.

27. The method for manufacturing a light-emitting element according to any one of claims 22 to 26, comprising, before the step of forming the light-emitting layer, a step of forming at least one functional layer facing a surface of the light-emitting layer, wherein a functional layer composition for forming the functional layer comprises nanoparticles and an organic ligand, and the resist layer is a first resist layer, the steps including: forming the functional layer by applying the functional layer composition onto a first or second electrode; forming a second resist layer by applying the resist agent composition onto the functional layer; and exposing the functional layer and the second resist layer to form a pattern in the second resist layer for forming the light-emitting layer, while forming a second reaction product layer on a surface of the second resist layer that contacts the functional layer.

28. A method for manufacturing a light-emitting element as described in claim 27, comprising a step of forming a plurality of the functional layers, and after a step of peeling and developing the light-emitting layer, the method includes a step of forming a second resist layer of a second layer by applying the resist agent composition, a step of forming a second functional layer on the second resist layer of the second layer, and a step of exposing at least the second resist layer of the second layer and the functional layer to light to form a second reaction product layer on the surface where the second resist layer of the second layer contacts the second functional layer.

29. A method for manufacturing a light-emitting element according to claim 27 or 28, comprising a step of forming a bank surrounding a light-emitting region in a non-light-emitting region surrounding the light-emitting region of the light-emitting element, wherein the bank is formed in the non-light-emitting region surrounding the light-emitting region when the first resist layer or the second resist layer is exposed.

30. The method for producing a light-emitting device according to any one of claims 22 to 29, wherein the composition for the light-emitting layer contains a precursor of a silicon oxide matrix.

31. The method for producing a light-emitting element according to any one of claims 22 to 30, wherein the base resin is selected from a water-soluble resin, a polymethyl(meth)acrylate resin, and a poly(alkoxystyrene) resin, and the photosensitizer is selected from a diazonaphthoquinone compound, a photoacid generator, or a photobase generator.

32. The method for producing a light-emitting element according to claim 31, wherein the base resin further contains a phenolic resin.

33. The method for manufacturing a light-emitting element according to any one of claims 22 to 32, wherein the base resin contains a cyclized rubber, and the photosensitizer contains a bisazide compound.

34. The method for producing a light-emitting element according to claim 31, wherein the water-soluble resin includes a graft copolymer or a block copolymer, and the graft copolymer and the block copolymer have at least two polymer units derived from different hydrophilic monomers.

35. The method for producing a light-emitting element according to claim 34, wherein the graft copolymer or block copolymer is a copolymer of a polymer unit in which a vinyl alcohol monomer unit is polymerized and a polymer unit in which an N-vinylpyrrolidone monomer unit is polymerized.

36. A method for producing a light-emitting element according to any one of claims 22 to 35, wherein the first reaction product is a compound selected from the group consisting of the molecular structure and a thioester compound, an amide compound, an ester compound, an acid halide, and a halide having the molecular structure, and the molecular structure is selected from a linear or branched saturated hydrocarbon group having 1 to 40 carbon atoms or an unsaturated hydrocarbon group.

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