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

Abstract

A blue light emitting element (5B) according to the present invention is provided with: a first electrode (22); a second electrode (25); and a functional layer (24B) which is arranged between the first electrode (22) and the second electrode (25), while comprising at least a blue light emitting layer (31B) that contains quantum dots. The blue light emitting layer (31B) at least partially contains a first ligand which is composed of at least one ligand selected from among a ligand that is composed of a halogen atom and a ligand that is composed of a sulfur atom; and the blue light emitting layer (31B) is composed of a first region (31BR1) which is a region of the blue light emitting layer (31B), the region containing at least a part of an end of the blue light emitting layer (31B), and a second region (31BR2) which is other than the first region (31BR1). The number of the first ligands contained in a unit volume of the first region (31BR1) is larger than the number of the first ligands contained in the unit volume of the second region (31BR2).

Description

[Technical field]

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

[0002] 2. Description of the Related Art In recent years, quantum dot light emitting diodes (QLEDs), which are light emitting elements, and display devices equipped with QLEDs have been attracting a great deal of attention.

[0003] However, the light emitting properties and reliability of the quantum dot-containing light emitting layer in the QLED are not satisfactory, and research is being actively conducted to improve the light emitting properties and reliability.

[0004] For example, Patent Document 1 describes a quantum dot composition in which fluoride-containing ligands or fluoride anions are bound to the surface of the quantum dots, a light-emitting layer containing quantum dots and fluoride-containing ligands or fluoride anions bound to the surface of the quantum dots, and an electroluminescent device including such a light-emitting layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication "JP2020-180278" Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of a light-emitting layer containing quantum dots, there is a problem that the quantum dots in the peripheral part of the light-emitting layer, which is a part of the light-emitting layer including the end of the light-emitting layer, deteriorate and become non-emitting due to the intrusion of impurities or foreign matter from the end of the light-emitting layer over time. Note that the end of the light-emitting layer means a part of the light-emitting layer formed by the multiple quantum dots constituting the side surface of the light-emitting layer among the multiple quantum dots contained in the light-emitting layer.

[0007] In the case where a light-emitting layer containing quantum dots is formed using the quantum dot composition described in Patent Document 1, and in the case of the light-emitting layer described in Patent Document 1, the number of the fluoride-containing ligands or the fluoride anions contained per unit volume of the light-emitting layer does not differ between the peripheral part of the light-emitting layer, which is a part of the light-emitting layer, and the central part of the light-emitting layer, which is the part other than the peripheral part. Note that the unit volume of the light-emitting layer means a part of the light-emitting layer having a size of 1 μm (thickness) × 1 μm (width) × 1 μm (length).

[0008] Therefore, if the number of the fluoride-containing ligands or the fluoride anions contained per unit volume in the entire light-emitting layer is increased to a level suitable for suppressing the intrusion of impurities or foreign matter from the edges of the light-emitting layer, the deterioration of the quantum dots in the peripheral parts of the light-emitting layer can be suppressed, thereby improving reliability. However, if the fluoride-containing ligands or the fluoride anions are present in excess even in the central part of the light-emitting layer, problems such as the quantum dots (QDs) agglomerating and the increase in the unevenness of the surface of the light-emitting layer causing leakage currents and the like arise, resulting in a problem of degraded light-emitting properties of the light-emitting layer.

[0009] On the other hand, if the number of the fluoride-containing ligands or the fluoride anions contained per unit volume in the entire light-emitting layer is reduced to a level at which the unevenness of the surface of the light-emitting layer is not increased, the light-emitting characteristics of the light-emitting layer can be improved. However, this leads to a problem that deterioration of the quantum dots cannot be suppressed in the peripheral part of the light-emitting layer, resulting in reduced reliability.

[0010] One aspect of the present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a light-emitting element, a method for manufacturing a light-emitting element, a display device, and a method for manufacturing a display device, which can protect quantum dots in the periphery of the light-emitting layer, i.e., ensure both reliability and the light-emitting characteristics of the light-emitting layer. [Means for solving the problem]

[0011] In order to solve the above problems, the light-emitting device of the present disclosure has the following features: A first electrode and a second electrode; a functional layer disposed between the first electrode and the second electrode and having at least a light-emitting layer including quantum dots; the light-emitting layer at least partially contains a first ligand which is at least one kind of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, and the light-emitting layer comprises a first region which is a part of the light-emitting layer including at least a part of an edge of the light-emitting layer, and a second region other than the first region; The number of the first ligands contained per unit volume of the first region is greater than the number of the first ligands contained per unit volume of the second region.

[0012] In order to solve the above problems, the method for producing a light-emitting element according to the present disclosure includes the steps of: a first electrode forming step of forming a first electrode; a first light-emitting layer forming step of forming a first light-emitting layer on the first electrode; and forming a second electrode on the first light-emitting layer, The first light-emitting layer forming step includes: a first quantum dot layer forming step of forming a first quantum dot layer on the first electrode; a photosensitive resin layer forming step of forming a photosensitive resin layer on the entire surface; a patterning step of removing the photosensitive resin layer on a first region, which is a partial region of the first quantum dot layer including at least a part of an end of the first quantum dot layer, by exposing and developing the photosensitive resin layer, and leaving the photosensitive resin layer on a second region of the first quantum dot layer other than the first region; A step of incorporating a first ligand into the first quantum dot layer by forming a solution containing a first ligand, the first ligand being at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, on the first region of the first quantum dot layer; and a photosensitive resin layer removal step of removing the photosensitive resin layer, which is performed after the step of incorporating a first ligand into the first quantum dot layer. Effect of the Invention

[0013] According to one aspect of the present disclosure, it is possible to provide a light-emitting element, a method for manufacturing a light-emitting element, a display device, and a method for manufacturing a display device, which can protect quantum dots in the periphery of the light-emitting layer, i.e., ensure reliability while ensuring the light-emitting characteristics of the light-emitting layer. [Brief description of the drawings]

[0014] [Figure 1] 1 is a plan view showing a schematic configuration of a display device according to a first embodiment. [Diagram 2] 1 is a cross-sectional view showing a schematic configuration of a display area of ​​the display device of Embodiment 1. FIG. [Diagram 3] 1 is a cross-sectional view showing a schematic configuration of a light-emitting element provided in the display device of Embodiment 1. FIG. [Figure 4] 2 is a plan view of a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device of Embodiment 1. FIG. [Diagram 5] FIG. 1(a) is a diagram showing the size of the peripheral and central parts of an emitting layer provided in a light-emitting element included in each subpixel of the display device of embodiment 1, and FIG. 1(b) is a diagram showing the relationship between the peripheral width of the emitting layer and the area ratio of the peripheral part and the area ratio of the central part to the area of ​​one subpixel. [Figure 6] 1(a) to 1(o) are diagrams illustrating an example of a process for forming a quantum dot layer by a lift-off method, which is part of a process for forming a light-emitting layer provided in a light-emitting element included in each subpixel of the display device of embodiment 1. [Figure 7]7(a), (b), (c), (d) and (e) are diagrams illustrating the remaining part of the light-emitting layer forming step that is performed after the quantum dot layer forming step shown in FIG. [Figure 8] 4 is a cross-sectional view showing a schematic configuration of a modified example of a light-emitting element provided in the display device of Embodiment 1 shown in FIG. [Figure 9] 13(a) to 13(j) are diagrams illustrating a part of still another process for forming the red light-emitting layer, the green light-emitting layer, and the blue light-emitting layer provided in the display device 1 of the first embodiment. [Figure 10] 9(a) to 9(j) are diagrams illustrating steps subsequent to the steps illustrated in FIG. 9(a) to FIG. 9(j). [Figure 11] 10(a) to 10(j) are diagrams illustrating steps subsequent to the steps illustrated in FIG. 10(a) to FIG. 10(j). [Figure 12] 11 is a plan view of a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device of Embodiment 2. FIG. [Figure 13] 10(a) to 10(e) are diagrams illustrating a part of a process for forming a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device of Embodiment 2. FIG. [Figure 14] 13(a) to 13(e) are diagrams illustrating still another process for forming a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device of Embodiment 2. FIG. [Figure 15] FIG. 11 is a plan view of a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device of Embodiment 3. [Figure 16] FIG. 11 is a plan view of a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device of Embodiment 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The following describes an embodiment of the present invention with reference to Figures 1 to 16. For the sake of convenience, components having the same functions as those described in a specific embodiment are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0016] [Embodiment 1] FIG. 1 is a plan view showing a schematic configuration of a display device 1 according to the first embodiment.

[0017] As shown in Fig. 1, the display device 1 includes a frame area NDA and a display area DA. The display area DA of the display device 1 includes a plurality of pixels PIX, each of which includes a red sub-pixel RSP, a green sub-pixel GSP, and a blue sub-pixel BSP. In this embodiment, a case in which one pixel PIX is composed of a red sub-pixel RSP, a green sub-pixel GSP, and a blue sub-pixel BSP will be described as an example, but the present invention is not limited to this. For example, one pixel PIX may include sub-pixels of other colors in addition to the red sub-pixel RSP, the green sub-pixel GSP, and the blue sub-pixel BSP.

[0018] FIG. 2 is a cross-sectional view showing a schematic configuration of the display area DA of the display device 1 of the first embodiment.

[0019] As shown in Figure 2, in the display area DA of the display device 1, a barrier layer 3, a thin film transistor layer 4 including a transistor TR, a red light-emitting element 5R, a green light-emitting element 5G, a blue light-emitting element 5B and a bank 23, a sealing layer 6, and a functional film 39 are provided on a substrate 12 in this order from the substrate 12 side.

[0020] The blue sub-pixel BSP provided in the display area DA of the display device 1 includes a blue light-emitting element 5B (first light-emitting element), the green sub-pixel GSP provided in the display area DA of the display device 1 includes a green light-emitting element 5G (second light-emitting element), and the red sub-pixel RSP provided in the display area DA of the display device 1 includes a red light-emitting element 5R (third light-emitting element).

[0021] The substrate 12 may be, for example, a resin substrate made of a resin material such as polyimide, or a glass substrate. In this embodiment, in order to make the display device 1 a flexible display device, a case where a resin substrate made of a resin material such as polyimide is used as the substrate 12 will be described as an example, but the present invention is not limited to this. When the display device 1 is a non-flexible display device, a glass substrate can be used as the substrate 12.

[0022] The barrier layer 3 is a layer that prevents foreign substances such as water and oxygen from penetrating into the transistor TR, the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B, and can be composed of, for example, a silicon oxide film, a silicon nitride film, or a silicon oxynitride film, or a laminated film of these, formed by a CVD method.

[0023] The transistor TR portion of the thin film transistor layer 4 including the transistor TR includes the semiconductor film SEM and the doped semiconductor films SEM' and SEM'', an inorganic insulating film 16, a gate electrode G, an inorganic insulating film 18, an inorganic insulating film 20, a source electrode S, a drain electrode D, and a planarization film 21, and the portion of the thin film transistor layer 4 including the transistor TR other than the transistor TR portion includes the inorganic insulating film 16, the inorganic insulating film 18, the inorganic insulating film 20, and the planarization film 21.

[0024] 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 transistor TR has a top gate structure as an example, but is not limited to this and the transistor TR may have a bottom gate structure.

[0025] 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.

[0026] The inorganic insulating film 16, the inorganic insulating film 18, and the inorganic insulating film 20 can be composed of, for example, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a laminate film of these films formed by a CVD method.

[0027] The planarizing film 21 can be made of a coatable organic material, such as polyimide or acrylic.

[0028] The red light emitting element 5R included in the red subpixel RSP includes an anode which is the first electrode 22 above the planarization film 21, a functional layer 24R including a red light emitting layer, and a cathode which is the second electrode 25, the green light emitting element 5G included in the green subpixel GSP includes an anode which is the first electrode 22 above the planarization film 21, a functional layer 24G including a green light emitting layer, and a cathode which is the second electrode 25, and the blue light emitting element 5B included in the blue subpixel BSP includes an anode which is the first electrode 22 above the planarization film 21, a functional layer 24B including a blue light emitting layer, and a cathode which is the second electrode 25. The insulating bank 23 covering the edge of the anode which is the first electrode 22 can be formed by applying an organic material such as polyimide or acrylic and then patterning it by photolithography.

[0029] The functional layer 24R including the red light-emitting layer can be formed, for example, by stacking a hole injection layer, a hole transport layer, a red light-emitting layer, an electron transport layer, and an electron injection layer in this order from the anode side, which is the first electrode 22. Of the functional layer 24R including the red light-emitting layer, one or more of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer may be omitted as appropriate. In this embodiment, the functional layer 24R including the red light-emitting layer is described by taking as an example a case in which the functional layer 24R including the red light-emitting layer is formed by stacking a hole transport layer, a red light-emitting layer, and an electron transport layer in this order from the anode side, which is the first electrode 22, but is not limited thereto.

[0030] The functional layer 24G including the green light-emitting layer can be formed, for example, by stacking a hole injection layer, a hole transport layer, a green light-emitting layer, an electron transport layer, and an electron injection layer in this order from the anode side, which is the first electrode 22. Of the functional layer 24G including the green light-emitting layer, one or more of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer may be omitted as appropriate. In this embodiment, the functional layer 24G including the green light-emitting layer is described by taking as an example a case in which the functional layer 24G including the green light-emitting layer is formed by stacking a hole transport layer, a green light-emitting layer, and an electron transport layer in this order from the anode side, which is the first electrode 22, but is not limited thereto.

[0031] The functional layer 24B including the blue light-emitting layer can be formed, for example, by stacking a hole injection layer, a hole transport layer, a blue light-emitting layer, an electron transport layer, and an electron injection layer in this order from the anode side, which is the first electrode 22. Of the functional layer 24B including the blue light-emitting layer, one or more of the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer may be omitted as appropriate. In this embodiment, the functional layer 24B including the blue light-emitting layer is described by taking as an example a case in which the functional layer 24B including the blue light-emitting layer is formed by stacking a hole transport layer, a blue light-emitting layer, and an electron transport layer in this order from the anode side, which is the first electrode 22, but is not limited thereto.

[0032] In this embodiment, the functional layer 24R including the red light-emitting layer, the functional layer 24G including the green light-emitting layer, and the functional layer 24B including the blue light-emitting layer each have a hole transport layer formed in the same process using the same material, and an electron transport layer formed in the same process using the same material, but the present invention is not limited to this. For example, the functional layer 24R including the red light-emitting layer, the functional layer 24G including the green light-emitting layer, and the functional layer 24B including the blue light-emitting layer may each further have at least one of a hole injection layer formed in the same process using the same material, and an electron injection layer formed in the same process using the same material. For example, each hole transport layer included in each functional layer 24R, 24G, and 24B may be formed from different materials. For example, the hole transport layers included in two functional layers among the functional layers 24R, 24G, and 24B may be formed in the same process using the same material, and only the hole transport layer included in the remaining functional layer may be formed in a different process using a different material. For example, the electron transport layers included in each of the functional layers 24R, 24G, and 24B may be formed of different materials, for example, the electron transport layers included in two of the functional layers 24R, 24G, and 24B may be formed in the same process using the same material, and only the electron transport layer included in the remaining functional layer may be formed in a separate process using a different material. For example, the hole injection layers included in each of the functional layers 24R, 24G, and 24B may be formed of different materials, for example, the hole injection layers included in two of the functional layers 24R, 24G, and 24B may be formed in the same process using the same material, and only the hole injection layer included in the remaining functional layer may be formed in a separate process using a different material. Furthermore, for example, each electron injection layer included in each functional layer 24R, 24G, and 24B may be formed from a different material. For example, the electron injection layers included in two of the functional layers 24R, 24G, and 24B may be formed in the same process using the same material, and only the electron injection layer included in the remaining functional layer may be formed in a separate process using a different material.

[0033] In this embodiment, the case where the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B are all QLEDs (quantum dot light emitting diodes) will be described as an example, but the present invention is not limited thereto, and at least one of the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B may be a QLED. For example, when one of the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B is a QLED, the remaining two may be OLEDs (organic light emitting diodes), and when two of the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B are QLEDs, the remaining one may be an OLED.

[0034] In the present embodiment, when the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B are each a QLED, the light emitting layer of each light emitting element includes quantum dots (QDs). The quantum dots (QDs) may have, for example, a core structure, a core / shell structure, a core / shell / shell structure, or a shell structure in which the core / ratio is continuously changed. The shell may completely cover the core, or may cover only a part of the core. In the case of a single element, the core part may be composed of, for example, Si, C, etc.; in the case of a binary element, the core part may be composed of, for example, CdSe, CdS, CdTe, InP, GaP, InN, ZnSe, ZnS, ZnTe, etc.; in the case of a ternary element, the core part may be composed of, for example, CdSeTe, GaInP, ZnSeTe, etc.; and in the case of a quaternary element, the core part may be composed of, for example, AIGS, etc. In the case of a binary system, the shell portion can be composed of, for example, CdS, CdTe, CdSe, ZnS, ZnSe, ZnTe, etc., and in the case of a ternary system, the shell portion can be composed of, for example, CdSSe, CdTeSe, CdSTe, ZnSSe, ZnSTe, ZnTeSe, AIP, etc.

[0035] The quantum dot (QD) means a dot with 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 be a polygonal cross-sectional shape, a rod-like three-dimensional shape, a branch-like three-dimensional shape, a three-dimensional shape with unevenness on the surface, or a combination thereof.

[0036] In this embodiment, an example is given in which the quantum dot (QD)-containing light-emitting layers of the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B all contain, at least in part, a first ligand which is at least one type of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom. However, this is not limited to this, and for example, as in embodiment 4 described below, among the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B, only the quantum dot (QD)-containing light-emitting layer of the blue light-emitting element 5B may contain, at least in part, a first ligand which is at least one type of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom.

[0037] A ligand is a compound that has a coordination function. When both a ligand and a quantum dot (QD) are contained, the ligand can be considered to be coordinated to the quantum dot (QD).

[0038] The ligand consisting of a halogen atom means a ligand consisting of a halogen atom such as F, Cl, Br, and I, and for example, F - , Cl - , Br - , I -In the anion state, it is attracted to the surface of a positively charged quantum dot (QD). If a ligand consisting of a halogen atom is coordinated to the quantum dot (QD), it is preferable because the stability and electron injection property are improved, and among them, a ligand consisting of fluorine, which has a strong coordination power to the quantum dot (QD), is more preferable. Therefore, the first ligand is preferably a ligand consisting of a halogen atom, and in this embodiment, in consideration of the strong coordination power to the quantum dot (QD), a case where fluorine is used as the first ligand will be described as an example, but it is not limited thereto.

[0039] The ligand consisting of a sulfur atom means a ligand consisting of S (sulfur), for example, S 2- In the anionic state, it is attracted to the surface of the positively charged quantum dot (QD). Ligands consisting of sulfur atoms also have a strong coordination force to quantum dots (QDs), which can improve their stability.

[0040] The light-emitting layer containing quantum dots (QD) may at least partially contain a second ligand, which is a ligand other than the first ligand. As the second ligand, for example, an organic ligand consisting of an organic molecule having a certain length to prevent the quantum dots (QD) from agglomerating with each other can be mentioned as an example, but is not limited thereto. As the organic ligand, for example, oleylamine, oleic acid, dodecanethiol, trioctylphosphine, trioctylphosphine oxide, tributylphosphine oxide, oleyl alcohol, etc. can be used, but is not limited thereto.

[0041] The first ligand or the second ligand is provided on the surface of the core when the quantum dot (QD) has a core structure, on the surface of the shell when the quantum dot (QD) has a shell structure and the shell completely covers the core, and on the surfaces of both the core and the shell when the quantum dot (QD) has a shell structure and the shell partially covers the core.

[0042] A control circuit including a transistor TR for controlling each of the red light emitting element 5R, green light emitting element 5G, and blue light emitting element 5B is provided in the thin film transistor layer 4 including the transistor TR for each of the red sub-pixel RSP, green sub-pixel GSP, and blue sub-pixel BSP. The control circuit including the transistor TR and the light emitting element provided for each of the red sub-pixel RSP, green sub-pixel GSP, and blue sub-pixel BSP are collectively referred to as a sub-pixel circuit.

[0043] The red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B shown in Fig. 2 may be of a top emission type or a bottom emission type. The red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B have a forward stack structure in which an anode as the first electrode 22, functional layers 24R, 24G, and 24B, and a cathode as the second electrode 25 are formed in this order from the substrate 12 side, and the cathode as the second electrode 25 is disposed as an upper layer than the anode as the first electrode 22. To make them of a top emission type, the anode as the first electrode 22 may be formed from an electrode material that reflects visible light, and the cathode as the second electrode 25 may be formed from an electrode material that transmits visible light, and to make them of a bottom emission type, the anode as the first electrode 22 may be formed from an electrode material that transmits visible light, and the cathode as the second electrode 25 may be formed from an electrode material that reflects visible light.

[0044] The electrode material that reflects visible light is not particularly limited as long as it can reflect visible light and has electrical conductivity, and examples thereof include metal materials such as Al, Mg, Li, and Ag, alloys of the metal materials, laminates of the metal materials and transparent metal oxides (e.g., indium tin oxide, indium zinc oxide, indium gallium zinc oxide, etc.), and laminates of the alloys and the transparent metal oxides.

[0045] 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 electrical 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.

[0046] In this embodiment, the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B are of a top-emission type, and the anode, which is the first electrode 22, is formed of a laminated film of ITO / Ag / ITO, which is an electrode material that reflects visible light, and the cathode, which is the second electrode 25, is formed of a thin film made of Ag, which is an electrode material that transmits visible light. However, the present invention is not limited to this example.

[0047] A typical electrode forming method can be used as a method for forming the anode as the first electrode 22 and the cathode as the second electrode 25, and examples of such methods include physical vapor deposition (PVD) methods such as vacuum deposition, sputtering, EB deposition, and ion plating, and chemical vapor deposition (CVD). A patterning method for the anode as the first electrode 22 and the cathode as the second electrode 25 is not particularly limited as long as it is a method that can form the anode into a desired pattern with high accuracy, and specific examples of such methods include photolithography and inkjet printing.

[0048] The sealing layer 6 is a light-transmitting film, and can be composed of, for example, an inorganic sealing film 26 covering the cathode which is the second electrode 25, an organic film 27 above the inorganic sealing film 26, and an inorganic sealing film 28 above the organic film 27. The sealing layer 6 prevents foreign matter such as water and oxygen from penetrating into the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B.

[0049] The inorganic sealing film 26 and the inorganic sealing film 28 are inorganic films, and may be formed, for example, by a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a laminated film of these films, which are formed by a CVD method. The organic film 27 is a light-transmitting organic film having a planarizing effect, and may be formed, for example, by a coatable organic material such as acrylic. The organic film 27 may be formed, for example, by an inkjet method. In the present embodiment, the sealing layer 6 is formed of two inorganic films and one organic film provided between the two inorganic films, but the lamination order of the two inorganic films and the one organic film is not limited to this. Furthermore, the sealing layer 6 may be formed only of an inorganic film, may be formed only of an organic film, may be formed of one inorganic film and two organic films, or may be formed of two or more inorganic films and two or more organic films.

[0050] The functional film 39 is, for example, a film having at least one of an optical compensation function, a touch sensor function, and a protection function.

[0051] FIG. 3 is a cross-sectional view showing a schematic configuration of a blue light emitting element 5B provided in the display device 1 of the first embodiment.

[0052] Figure 4 is a plan view of the red light-emitting layer 31R provided in the red light-emitting element 5R included in the red subpixel RSP of the display device 1 of embodiment 1, the green light-emitting layer 31G provided in the green light-emitting element 5G included in the green subpixel GSP, and the blue light-emitting layer 31B provided in the blue light-emitting element 5B included in the blue subpixel BSP.

[0053] 3, the blue light-emitting element 5B includes a first electrode 22, a second electrode 25, and a functional layer 24B disposed between the first electrode 22 and the second electrode 25 and having at least a blue light-emitting layer 31B containing quantum dots (QDs). The functional layer 24B is configured by laminating, in this order from the first electrode 22 side, a hole transport layer 30, a blue light-emitting layer 31B, and an electron transport layer 32.

[0054] The blue light-emitting layer 31B provided in the blue light-emitting element 5B only needs to be composed of a first region 31BR1 which is a partial region of the light-emitting layer 31B including at least a part of an end portion of the blue light-emitting layer 31B and which includes at least a first ligand which is at least one kind of ligand selected from a ligand including a halogen atom and a ligand including a sulfur atom, and a second region 31BR2 other than the first region 31BR1. In other words, the second region 31BR2 of the blue light-emitting layer 31B may or may not be surrounded by the first region 31BR1 of the blue light-emitting layer 31B.

[0055] In this embodiment, as shown in Figures 3 and 4, the blue light-emitting layer 31B provided in the blue light-emitting element 5B at least partially contains a first ligand which is at least one type of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, and is composed of a first region 31BR1 which is a partial region of the blue light-emitting layer 31B including all of the ends of the blue light-emitting layer 31B, that is, an upper end 31BET of the blue light-emitting layer 31B, a right end 31BER of the blue light-emitting layer 31B, a left end 31BEL of the blue light-emitting layer 31B, and a lower end 31BEB of the blue light-emitting layer 31B, and a second region 31BR2 other than the first region 31BR1, i.e., a case in which the second region 31BR2 of the blue light-emitting layer 31B is surrounded by the first region 31BR1 of the blue light-emitting layer 31B will be described as an example, but the present invention is not limited to this.

[0056] The end of the light-emitting layer (for example, the end of the blue light-emitting layer 31B) means a part of the light-emitting layer formed by a plurality of quantum dots (QDs) constituting the side surface of the light-emitting layer (for example, the blue light-emitting layer 31B) among a plurality of quantum dots (QDs) contained in the light-emitting layer (for example, the blue light-emitting layer 31B). In the present embodiment, the case where the blue light-emitting layer 31B has the upper end 31BET of the blue light-emitting layer 31B, the right end 31BER of the blue light-emitting layer 31B, the left end 31BEL of the blue light-emitting layer 31B, and the lower end 31BEB of the blue light-emitting layer 31B has been described as an example, but the present invention is not limited thereto, and if the shape of the blue light-emitting layer 31B changes, the shape of the end also changes.

[0057] 3 and 4, the number of first ligands, which are at least one kind of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, contained per unit volume of first region 31BR1 of blue light-emitting layer 31B is greater than the number of the first ligands contained per unit volume of second region 31BR2 of blue light-emitting layer 31B. Note that the unit volume of a light-emitting layer (e.g., blue light-emitting layer 31B) means a part of a light-emitting layer (e.g., blue light-emitting layer 31B) having a size of 1 μm (thickness) × 1 μm (width) × 1 μm (length).

[0058] For example, organic ligands such as acid (-COOH) and thiol (-SH) have a weaker coordination force with the quantum dot (QD) than the first ligand, which is at least one ligand selected from the group consisting of a halogen atom and a sulfur atom, and are easily removed from the quantum dot (QD). Therefore, when impurities enter the light-emitting layer containing the quantum dot (QD) with the organic ligand from the end of the light-emitting layer, the organic ligand may be removed from the quantum dot (QD) and the quantum dot (QD) may not be protected against the impurities. This causes the quantum dot (QD) to deteriorate and become non-luminescent.

[0059] 3 and 4, the number of the first ligands contained per unit volume in the first region 31BR1 of the blue light-emitting layer 31B is greater than the number of the first ligands contained per unit volume in the second region 31BR2 of the blue light-emitting layer 31B. That is, the quantum dots (QDs) in the first region 31BR1 of the blue light-emitting layer 31B are excessively coordinated with at least one kind of first ligand selected from a ligand made of a halogen atom and a ligand made of a sulfur atom, which have strong coordinating power. Therefore, even if impurities enter the quantum dots (QDs) in the first region 31BR1 of the blue light-emitting layer 31B, the quantum dots (QDs) can be protected from the impurities. On the other hand, if the first ligand is coordinated in excess, the quantum dots (QDs) will aggregate and the unevenness of the light-emitting layer surface will increase, resulting in problems such as leakage current. Therefore, by limiting the amount of the first ligand in excess to the first region 31BR1 (peripheral portion) of the blue light-emitting layer 31B, it is possible to ensure both the light-emitting characteristics of the blue light-emitting element 5B having the blue light-emitting layer 31B and the protection of the quantum dots (QDs) in the first region 31BR1 of the blue light-emitting layer 31B, i.e., ensuring reliability.

[0060] Furthermore, as in this embodiment, when the blue light-emitting layer 31B shown in FIGS. 3 and 4 at least partially contains second ligands that are ligands other than the first ligands, the ratio of the number of the first ligands in the first region 31BR1 of the blue light-emitting layer 31B to the total number of ligands in the first region 31BR1 of the blue light-emitting layer 31B, which is the sum of the number of the first ligands in the first region 31BR1 (peripheral portion) of the blue light-emitting layer 31B and the number of the second ligands in the first region 31BR1 of the blue light-emitting layer 31B, is greater than the ratio of the number of the first ligands in the second region 31BR2 of the blue light-emitting layer 31B to the total number of ligands in the second region 31BR2 of the blue light-emitting layer 31B, which is the sum of the number of the first ligands in the second region 31BR2 (central portion) of the blue light-emitting layer 31B and the number of the second ligands in the second region 31BR2 of the blue light-emitting layer 31B. That is, the quantum dots (QDs) in the first region 31BR1 of the blue light-emitting layer 31B are coordinated with an excess of the first ligand, which is at least one type of ligand selected from a ligand made of a halogen atom and a ligand made of a sulfur atom, which have strong coordination power, so that even if impurities enter the quantum dots (QDs) in the first region 31BR1 of the blue light-emitting layer 31B, the quantum dots (QDs) can be protected from the impurities. On the other hand, if the first ligand is coordinated with an excess, the quantum dots (QDs) aggregate with each other, and the unevenness of the light-emitting layer surface increases, causing problems such as the generation of leakage current. Therefore, by limiting the excess of the first ligand to the first region 31BR1 (periphery) of the blue light-emitting layer 31B, it is possible to ensure both the light-emitting characteristics of the blue light-emitting element 5B including the blue light-emitting layer 31B and the protection of the quantum dots (QDs) in the first region 31BR1 of the blue light-emitting layer 31B, i.e., to ensure reliability.

[0061] In this embodiment, as shown in FIG. 4, the red light-emitting layer 31R provided in the red light-emitting element 5R at least partially contains a first ligand which is at least one type of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, and is composed of a first region 31RR1 which is a partial region of the red light-emitting layer 31R including all of the ends of the red light-emitting layer 31R, that is, an upper end 31RET of the red light-emitting layer 31R, a right end 31RER of the red light-emitting layer 31R, a left end 31REL of the red light-emitting layer 31R, and a lower end 31REB of the red light-emitting layer 31R, and a second region 31RR2 other than the first region 31RR1, i.e., a case where the second region 31RR2 of the red light-emitting layer 31R is surrounded by the first region 31RR1 of the red light-emitting layer 31R will be described as an example, but the present invention is not limited to this. As in the blue light-emitting layer 31B, the quantum dots (QDs) in the first region 31RR1 of the red light-emitting layer 31R are coordinated with an excess of the first ligand, which is at least one ligand selected from a ligand made of a halogen atom and a ligand made of a sulfur atom, which have strong coordination power, so that even if impurities enter the quantum dots (QDs) in the first region 31RR1 of the red light-emitting layer 31R, the quantum dots (QDs) can be protected from the impurities. On the other hand, if the first ligand is coordinated in excess, the quantum dots (QDs) aggregate with each other, and the unevenness of the light-emitting layer surface increases, causing problems such as the generation of a leak current. Therefore, by limiting the excess of the first ligand to the first region 31RR1 (periphery) of the red light-emitting layer 31R, it is possible to ensure both the light-emitting characteristics of the red light-emitting element 5R including the red light-emitting layer 31R and the protection of the quantum dots (QDs) in the first region 31RR1 of the red light-emitting layer 31R, i.e., to ensure reliability.

[0062] In addition, in this embodiment, as shown in FIG. 4, the green light-emitting layer 31G provided in the green light-emitting element 5G at least partially contains a first ligand which is at least one type of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, and is composed of a first region 31GR1 which is a partial region of the green light-emitting layer 31G including all of the ends of the green light-emitting layer 31G, that is, an upper end 31GET of the green light-emitting layer 31G, a right end 31GER of the green light-emitting layer 31G, a left end 31GEL of the green light-emitting layer 31R, and a lower end 31GEB of the green light-emitting layer 31G, and a second region 31GR2 other than the first region 31GR1, that is, a case in which the second region 31GR2 of the green light-emitting layer 31G is surrounded by the first region 31GR1 of the green light-emitting layer 31G will be described as an example, but the present invention is not limited to this. As in the blue light-emitting layer 31B and the red light-emitting layer 31R, the quantum dots (QDs) in the first region 31GR1 of the green light-emitting layer 31G are coordinated with an excess of the first ligand, which is at least one ligand selected from a ligand made of a halogen atom and a ligand made of a sulfur atom, which have strong coordination power, so that even if impurities enter the quantum dots (QDs) in the first region 31GR1 of the green light-emitting layer 31G, the quantum dots (QDs) can be protected from the impurities. On the other hand, if the first ligand is coordinated in excess, the quantum dots (QDs) aggregate with each other, and the unevenness of the light-emitting layer surface increases, causing problems such as the generation of a leak current. Therefore, by limiting the excess of the first ligand to the first region 31GR1 (periphery) of the green light-emitting layer 31G, it is possible to ensure both the light-emitting characteristics of the green light-emitting element 5G including the green light-emitting layer 31G and the protection of the quantum dots (QDs) in the first region 31GR1 of the green light-emitting layer 31G, i.e., to ensure reliability.

[0063] In this embodiment, as shown in Fig. 4, the first ligand, which is at least one kind of ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, is included only in the first region 31RR1 of the red light emitting layer 31R provided in the red light emitting element 5R, only in the first region 31GR1 of the green light emitting layer 31G provided in the green light emitting element 5G, and only in the first region 31BR1 of the blue light emitting layer 31B provided in the blue light emitting element 5B. Therefore, the first ligand is not included in the second region 31RR2 of the red light emitting layer 31R provided in the red light emitting element 5R, the second region 31GR2 of the green light emitting layer 31G provided in the green light emitting element 5G, and the second region 31BR2 of the blue light emitting layer 31B provided in the blue light emitting element 5B. Therefore, it is possible to more reliably achieve both the light emitting characteristics and the reliability in each of the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B. Without being limited thereto, the first ligand may be included in the first region 31RR1 and the second region 31RR2 of the red light-emitting layer 31R provided in the red light-emitting element 5R, the first region 31GR1 and the second region 31GR2 of the green light-emitting layer 31G provided in the green light-emitting element 5G, and the first region 31BR1 and the second region 31BR2 of the blue light-emitting layer 31B provided in the blue light-emitting element 5B.

[0064] In this embodiment, the red light-emitting layer 31R of the red light-emitting element 5R, the green light-emitting layer 31G of the green light-emitting element 5G, and the blue light-emitting layer 31B of the blue light-emitting element 5B each contain an organic ligand in the first region and the second region as a second ligand other than the first ligand. With this configuration, it is possible to suppress aggregation of quantum dots (QDs) in the first region and the second region, and it is possible to improve the light-emitting characteristics of the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B.

[0065] Furthermore, in this embodiment, in each of the red light-emitting layer 31R provided in the red light-emitting element 5R, the green light-emitting layer 31G provided in the green light-emitting element 5G, and the blue light-emitting layer 31B provided in the blue light-emitting element 5B, the number of organic ligands as the second ligands contained per unit volume of the second region is greater than the number of organic ligands as the second ligands contained per unit volume of the first region. With this configuration, it is possible to improve the light-emitting characteristics while suppressing a decrease in the reliability of the red light-emitting element 5R, the green light-emitting element 5G, and the blue light-emitting element 5B.

[0066] Furthermore, in each of the red light-emitting layer 31R provided in the red light-emitting element 5R, the green light-emitting layer 31G provided in the green light-emitting element 5G, and the blue light-emitting layer 31B provided in the blue light-emitting element 5B, it is preferable that the ratio of the number of the first ligands in the first region to the total number of ligands in the first region, which is the sum of the number of the first ligands in the first region and the number of the organic ligands in the first region, is greater than the ratio of the number of the first ligands in the second region to the total number of ligands in the second region, which is the sum of the number of the first ligands in the second region and the number of the organic ligands in the second region.

[0067] The ratio of the number of the first ligands in the first region to the total number of ligands in the first region can be calculated as the ratio of the number of the first ligands to the total number of ligands per quantum dot (QD) contained in the first region, and the ratio of the number of the first ligands in the second region to the total number of ligands in the second region can be calculated as the ratio of the number of the first ligands to the total number of ligands per quantum dot (QD) contained in the second region.

[0068] The following shows the results of calculations of the maximum ratio of the number of fluorine atoms that are the first ligands in the second region (central portion) to the total number of ligands in the second region, which can prevent aggregation of quantum dots (QDs) in the second region (central portion) when the first ligand is fluorine.

[0069] If the particle size of the quantum dots (QDs) contained in the first region (peripheral region) and the second region (central region) is 3 nm, the surface area of ​​the quantum dots (QDs) is 4π×1.5 nm×1.5 nm=28.26 nm 2 The diameter of the first ligand, fluorine, is fluorine ion (F - The area occupied by one fluorine atom, which is the first ligand, is calculated as π×0.13 nm×0.13 nm=0.053066 nm 2 The number of fluorines, which are the first ligands, per quantum dot (QD) can be calculated by (surface area of ​​quantum dot (QD) / area occupied by one fluorine) and is 533. The number of organic ligands per quantum dot (QD) is 12 quantum dots (QDs) arranged closely to each other when a plurality of quantum dots (QDs) are closely packed. Since the organic ligands are easily removed by environmental factors such as heat and coating process, in order to prevent the close-packed quantum dots (QDs) from agglomerating, if it is necessary to provide at least 10 organic ligands per 12 closely arranged quantum dots (QDs), the number of organic ligands per quantum dot (QD) is 120. The ratio of the number of fluorines as the first ligands to the total number of ligands per quantum dot (QD) contained in the second region (central part) is 82% when calculated from (the number of fluorines as the first ligands per quantum dot (QD)) / (the number of fluorines as the first ligands per quantum dot (QD)+the number of organic ligands per quantum dot (QD)). Therefore, in the second region (central part), it is desirable that the ratio of the number of fluorines as the first ligands to the total number of ligands per quantum dot (QD) contained in the second region is 82% or less so that the quantum dots (QD) do not aggregate with each other. On the other hand, in the first region (peripheral part), it is desirable that the ratio of the number of fluorines as the first ligands to the total number of ligands per quantum dot (QD) contained in the first region is higher than 82% so that the quantum dots (QD) can be strongly protected even if the quantum dots (QD) aggregate with each other.

[0070] 5(a) is a diagram showing the sizes of the first region (peripheral portion) 31BR1 and the second region (central portion) 31BR2 of the blue light-emitting layer 31B provided in the blue light-emitting element 5B included in the blue subpixel BSP of the display device 1 of Embodiment 1, and FIG. 5(b) is a diagram showing the relationship between the peripheral width 31BR1H of the blue light-emitting layer 31B and the area ratio of the first region (peripheral portion) 31BR1 and the area ratio of the second region (central portion) 31BR2 to the area of ​​the blue light-emitting layer 31B. Note that the peripheral width 31BR1H of the blue light-emitting layer 31B is the width of the first region (peripheral portion) 31BR1, which is the shortest distance from an end of the blue light-emitting layer 31B to the second region (central portion) 31BR2.

[0071] Since the first region (peripheral portion) 31BR1 of the blue light-emitting layer 31B contains an excess of fluorine, which is the first ligand, leakage current occurs due to unevenness on the light-emitting layer surface caused by aggregation of quantum dots (QDs). Since this leakage current is proportional to the area of ​​the first region (peripheral portion) 31BR1 of the blue light-emitting layer 31B, the light-emitting characteristics of the entire blue light-emitting layer 31B can be maintained by setting the ratio of the area of ​​the first region (peripheral portion) 31BR1 to the area of ​​the blue light-emitting layer 31B to approximately 33% or less. As shown in (a) of FIG. 5, when the area of ​​the blue light-emitting layer 31B is 100 μm × 30 μm = 3000 μm 2 In this case, it is preferable that the peripheral width 31BR1H of the blue light-emitting layer 31B is 4 μm or less. If the peripheral width 31BR1H is 4 μm, the area of ​​the first region (peripheral portion) 31BR1 is 4 μm×100 μm+4 μm×100 μm+4 μm×22 μm+4 μm×22 μm=976 μm 2 The ratio of the area of ​​the first region (peripheral portion) 31BR1 to the area of ​​the blue light-emitting layer 31B is 976 μm 2 / 3000μm 2Therefore, the area ratio is 0.33 (33%). On the other hand, when ease of manufacture is taken into consideration, the lower limit of peripheral width 31BR1H of blue light-emitting layer 31B is 1 μm, and peripheral width 31BR1H of blue light-emitting layer 31B is preferably set to 1 μm or more. If peripheral width 31BR1H of blue light-emitting layer 31B is set to 1 μm, the area of ​​first region (peripheral portion) 31BR1 is 1 μm×100 μm+1 μm×100 μm+1 μm×28 μm+1 μm×28 μm=256 μm 2 The ratio of the area of ​​the first region (peripheral portion) 31BR1 to the area of ​​the blue light-emitting layer 31B is 256 μm 2 / 3000μm 2 which is 0.085 (8.5%).

[0072] For the above reasons, as shown in FIG. 5(b), the ratio of the area of ​​the first region (peripheral portion) 31BR1 to the area of ​​the blue light-emitting layer 31B is preferably 8.5% or more and 33% or less.

[0073] Although the blue light-emitting layer 31B has been described as an example above, the red light-emitting layer 31R and the green light-emitting layer 31G are similar, and therefore description thereof will be omitted here.

[0074] As described above, the red light emitting element 5R having the red light emitting layer 31R, the green light emitting element 5G having the green light emitting layer 31G, and the blue light emitting element 5B having the blue light emitting layer 31B can protect the quantum dots in the periphery of the light emitting layer, i.e., ensure reliability and ensure the light emitting characteristics of the light emitting layer. The display device 1 having the red light emitting element 5R, the green light emitting element 5G, and the blue light emitting element 5B can also protect the quantum dots in the periphery of the light emitting layer, i.e., ensure reliability and ensure the light emitting characteristics of the light emitting layer.

[0075] The manufacturing method of the red light-emitting element 5R provided in the above-mentioned display device 1 includes a first electrode formation step of forming a first electrode 22, a red light-emitting layer formation step of forming a red light-emitting layer 31R on the first electrode 22, and a second electrode formation step of forming a second electrode 25 on the red light-emitting layer 31R. The manufacturing method of the green light-emitting element 5G includes a first electrode formation step of forming the first electrode 22, a green light-emitting layer formation step of forming a green light-emitting layer 31G on the first electrode 22, and a second electrode formation step of forming a second electrode 25 on the green light-emitting layer 31G. The manufacturing method of the blue light-emitting element 5B includes a first electrode formation step of forming the first electrode 22, a blue light-emitting layer formation step of forming a blue light-emitting layer 31B on the first electrode 22, and a second electrode formation step of forming a second electrode 25 on the blue light-emitting layer 31B. In addition, the first electrode 22 of the red light-emitting element 5R, the first electrode 22 of the green light-emitting element 5G, and the first electrode 22 of the blue light-emitting element 5B can be formed in a single first electrode formation process, and the second electrode 25 of the red light-emitting element 5R, the second electrode 25 of the green light-emitting element 5G, and the second electrode 25 of the blue light-emitting element 5B can also be formed in a single second electrode formation process.

[0076] Hereinafter, a red light-emitting layer forming process for forming red light-emitting layer 31R, a green light-emitting layer forming process for forming green light-emitting layer 31G, and a blue light-emitting layer forming process for forming blue light-emitting layer 31B will be described with reference to Figures 6 and 7.

[0077] 6(a) to 6(o) are diagrams showing an example of a process for forming a quantum dot layer by a lift-off method, which is a part of a process for forming a light-emitting layer provided in a light-emitting element included in each subpixel of the display device 1 of embodiment 1. Note that in Fig. 6(a) to 6(o), the first electrode 22 provided in the light-emitting element of each color is omitted.

[0078] The patterning process of the red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the blue-light-emitting quantum dot layer 41B using the lift-off method includes the steps of forming a first photosensitive resin layer 40A on the hole transport layer 30 shown in FIG. 6(a), exposing the first photosensitive resin layer 40A through a mask M1 shown in FIG. 6(b), developing the first photosensitive resin layer 40A using a developing solution shown in FIG. 6(c) to form an opening in the first photosensitive resin layer 40A, applying and heat-treating a solution containing red-light-emitting quantum dots shown in FIG. 6(d) to obtain the red-light-emitting quantum dot layer 41R, and removing the first photosensitive resin layer 40A using a resist remover shown in FIG. 6(e) to obtain the patterned red-light-emitting quantum dot layer 41R. The patterning process of the red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the blue-light-emitting quantum dot layer 41B using the lift-off method further includes the steps of forming a second photosensitive resin layer 40B on the red-light-emitting quantum dot layer 41R and the hole transport layer 30 shown in FIG. 6(f), exposing the second photosensitive resin layer 40B through a mask M2 shown in FIG. 6(g), developing the second photosensitive resin layer 40B using a developing solution shown in FIG. 6(h) to form an opening in the second photosensitive resin layer 40B, applying a solution containing green-light-emitting quantum dots shown in FIG. 6(i) and heat treating the solution to obtain a green-light-emitting quantum dot layer 41G, and removing the second photosensitive resin layer 40B using a resist remover shown in FIG. 6(j) to obtain a patterned green-light-emitting quantum dot layer 41G. The patterning process of the red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the blue-light-emitting quantum dot layer 41B using the lift-off method further includes the steps of forming a third photosensitive resin layer 40C on the red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the hole transport layer 30, as shown in FIG. 6(k); exposing the third photosensitive resin layer 40C through a mask M3, as shown in FIG. 6(l); developing the third photosensitive resin layer 40C using a developing solution, as shown in FIG. 6(m), to form an opening in the third photosensitive resin layer 40C; applying and heat-treating a solution containing blue-light-emitting quantum dots, as shown in FIG. 6(n), to obtain the blue-light-emitting quantum dot layer 41B; and removing the third photosensitive resin layer 40C using a resist remover, as shown in FIG. 6(o), to obtain the patterned blue-light-emitting quantum dot layer 41B.As the resist removal liquid shown in Fig. 6(e), Fig. 6(j) and Fig. 6(o), for example, PGMEA can be used, but is not limited thereto. In addition, in the present embodiment, the case where the red light emitting quantum dot layer 41R, the green light emitting quantum dot layer 41G and the blue light emitting quantum dot layer 41B are formed in this order is described as an example, but is not limited thereto, and any color quantum dot layer may be formed first.

[0079] Figures 7(a), 7(b), 7(c), 7(d), and 7(e) are diagrams showing a remaining part of the light-emitting layer forming process performed after the quantum dot layer forming process shown in Figure 6. Note that in Figures 7(a) to 7(e), the first electrodes 22 provided on the light-emitting elements of each color are omitted.

[0080] As shown in (a) of Fig. 7, the red light-emitting quantum dots QD1 included in the red light-emitting quantum dot layer 41R are provided with an organic ligand OL1, the green light-emitting quantum dots QD2 included in the green light-emitting quantum dot layer 41G are provided with an organic ligand OL2, and the blue light-emitting quantum dots QD3 included in the blue light-emitting quantum dot layer 41B are provided with an organic ligand OL3. This is because, in the process of obtaining the red light-emitting quantum dot layer 41R shown in (d) of Fig. 6, a solution containing the red light-emitting quantum dots QD1 and the organic ligand OL1 is applied and heat-treated to form the red light-emitting quantum dot layer 41R, in the process of obtaining the green light-emitting quantum dot layer 41G shown in (i) of Fig. 6, a solution containing the green light-emitting quantum dots QD2 and the organic ligand OL2 is applied and heat-treated to form the green light-emitting quantum dot layer 41G, and in the process of obtaining the blue light-emitting quantum dot layer 41B shown in (n) of Fig. 6, a solution containing the blue light-emitting quantum dots QD3 and the organic ligand OL3 is applied and heat-treated to form the blue light-emitting quantum dot layer 41B. By using such a method, it is possible to incorporate an organic ligand without providing a separate step of incorporating an organic ligand. Note that the organic ligands OL1, OL2, and OL3 may be the same organic ligand, or at least one of the organic ligands OL1, OL2, and OL3 may be a different organic ligand.

[0081] Without being limited thereto, for example, in the step of obtaining the red light-emitting quantum dot layer 41R shown in (d) of Fig. 6, a solution containing the red light-emitting quantum dots QD1 and the above-mentioned first ligand is applied and heat-treated to form the red light-emitting quantum dot layer 41R, in the step of obtaining the green light-emitting quantum dot layer 41G shown in (i) of Fig. 6, a solution containing the green light-emitting quantum dots QD2 and the above-mentioned first ligand is applied and heat-treated to form the green light-emitting quantum dot layer 41G, and in the step of obtaining the blue light-emitting quantum dot layer 41B shown in (n) of Fig. 6, a solution containing the blue light-emitting quantum dots QD3 and the above-mentioned first ligand is applied and heat-treated to form the blue light-emitting quantum dot layer 41B. By using such a method, a quantum dot layer containing the first ligand can be formed during the quantum dot layer formation step shown in Fig. 6.

[0082] As shown in (a) and (b) of FIG. 7, a photosensitive resin layer forming process is performed to form a photosensitive resin layer 40D on the entire surface of the red light-emitting quantum dot layer 41R, the green light-emitting quantum dot layer 41G, the blue light-emitting quantum dot layer 41B, and the hole transport layer 30, and a mask M4 is used to expose the photosensitive resin layer 40D using a mask M4 and then developed to form the photosensitive resin layer 40D on a first region that is a partial region of the red light-emitting quantum dot layer 41R including at least a part of the end of the red light-emitting quantum dot layer 41R, and the photosensitive resin layer 40D on a first region that is a partial region of the green light-emitting quantum dot layer 41G including at least a part of the end of the green light-emitting quantum dot layer 41G. A patterning process of the photosensitive resin layer 40D was performed in which the photosensitive resin layer 40D on the first region, which is a part of the blue-light-emitting quantum dot layer 41B including at least a part of the end of the blue-light-emitting quantum dot layer 41B, and the photosensitive resin layer 40D on the second region of the red-light-emitting quantum dot layer 41R other than the first region of the red-light-emitting quantum dot layer 41R, the photosensitive resin layer 40D on the second region of the green-light-emitting quantum dot layer 41G other than the first region of the green-light-emitting quantum dot layer 41G, and the photosensitive resin layer 40D on the second region of the blue-light-emitting quantum dot layer 41B other than the first region of the blue-light-emitting quantum dot layer 41B were left.

[0083] In this embodiment, as shown in FIG. 7B, in the patterning process of the photosensitive resin layer 40D, the photosensitive resin layer 40D on the first region which is a part of the red light-emitting quantum dot layer 41R including all of the ends of the red light-emitting quantum dot layer 41R, the photosensitive resin layer 40D on the first region which is a part of the green light-emitting quantum dot layer 41G including all of the ends of the green light-emitting quantum dot layer 41G, and the blue light-emitting quantum dot layer 41B including all of the ends of the blue light-emitting quantum dot layer 41B are patterned. The photosensitive resin layer 40D on the first region, which is a part of the layer 41B, was removed, and the photosensitive resin layer 40D on the second region of the red light-emitting quantum dot layer 41R other than the first region of the red light-emitting quantum dot layer 41R, the photosensitive resin layer 40D on the second region of the green light-emitting quantum dot layer 41G other than the first region of the green light-emitting quantum dot layer 41G, and the photosensitive resin layer 40D on the second region of the blue light-emitting quantum dot layer 41B other than the first region of the blue light-emitting quantum dot layer 41B were left. That is, the photosensitive resin layer 40D was removed in a frame shape, but the present invention is not limited to this.

[0084] Then, as shown in FIG. 7(c), after the above-mentioned patterning process of the photosensitive resin layer 40D and before the introduction process of the first ligand HL1 shown in FIG. 7(d), a cleaning process for removing the organic ligands OL1, OL2, and OL3 was performed. In this cleaning process, at least a part of the organic ligand OL1 in the first region of the red light-emitting quantum dot layer 41R, at least a part of the organic ligand OL2 in the first region of the green light-emitting quantum dot layer 41G, and at least a part of the organic ligand OL3 in the first region of the blue light-emitting quantum dot layer 41B are removed by an alcohol solution. Note that, for example, methanol or ethanol can be suitably used as the alcohol solution, but is not limited thereto. In this way, by performing the cleaning process for removing the organic ligands OL1, OL2, and OL3 in the first region, the ratio of the organic ligands OL1, OL2, and OL3 in the first region to the first ligand HL1 can be easily adjusted.

[0085] Thereafter, as shown in FIG. 7(d), a solution containing a first ligand HL1, which is at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, was formed on the first region of the red light-emitting quantum dot layer 41R, the first region of the green light-emitting quantum dot layer 41G, and the first region of the blue light-emitting quantum dot layer 41B, thereby performing a step of incorporating the first ligand HL1 into the red light-emitting quantum dot layer 41R, the green light-emitting quantum dot layer 41G, and the blue light-emitting quantum dot layer 41B. In addition, after the step of incorporating the first ligand HL1, a step of removing the solvent (for example, a heat treatment step or a drying step) may be performed as necessary. The solution containing the first ligand HL1 contains the first ligand HL1 and a solvent that dissolves or disperses the first ligand HL1. That is, the solution containing the first ligand HL1 contains, for example, F dissociated in the solvent. - , Cl - , Br - , I - , S 2- and the corresponding cation. As a solvent for dissolving or dispersing the first ligand HL1, for example, DMSO (dimethyl sulfoxide), methanol, or ethanol can be used. The content of the first ligand HL1 in the solution is within a range in which the first ligand HL1 can be dissolved or dispersed in the solvent used, and can be appropriately determined in consideration of the amount of the first ligand HL1 to be incorporated. In this embodiment, fluorine, which is a ligand consisting of halogen atoms, is used as the first ligand HL1, and a solution containing fluorine is used as the solution containing the first ligand HL1. As a solution containing the first ligand HL1, for example, zinc fluoride (ZnF2) is dissolved in ethanol, and F - and Zn 2+ The solution in which tetrabutylammonium fluoride (TBAF) is formed may be used. - and (CH3CH2CH2CH2)4N + Alternatively, the solution in which the above is formed may be used.

[0086] Then, as shown in (e) of Figure 7, after the process of incorporating the first ligand HL1, a photosensitive resin layer removal process of removing the photosensitive resin layer 40D is performed, and a red light-emitting layer 31R consisting of a first region 31RR1 and a second region 31RR2, a green light-emitting layer 31G consisting of a first region 31GR1 and a second region 31GR2, and a blue light-emitting layer 31B consisting of a first region 31BR1 and a second region 31BR2 are formed on the hole transport layer 30.

[0087] According to the above-mentioned manufacturing method, the steps shown in FIG. 7(a) to FIG. 7(e) are performed on the entire red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the blue-light-emitting quantum dot layer 41B formed by the method shown in FIG. 6, so that the number of manufacturing steps can be reduced.

[0088] FIG. 8 is a cross-sectional view showing a schematic configuration of a blue light-emitting element 5B' which is a modification of the blue light-emitting element 5B provided in the display device 1 of the first embodiment shown in FIG.

[0089] 8, the blue light-emitting element 5B' includes a first electrode 22, a second electrode 25, and a functional layer 24B disposed between the first electrode 22 and the second electrode 25 and having at least a blue light-emitting layer 31B containing quantum dots (QDs). The functional layer 24B differs from the blue light-emitting element 5B shown in FIG. 3 in that the functional layer 24B is configured by stacking, in this order from the first electrode 22 side, an electron transport layer 32, a blue light-emitting layer 31B, and a hole transport layer 30.

[0090] The blue light emitting element 5B' shown in Fig. 8 may be of a top emission type or a bottom emission type. The blue light emitting element 5B' has an inverted stack structure in which the cathode as the first electrode 22, the electron transport layer 32, the blue light emitting layer 31B, the hole transport layer 30, and the anode as the second electrode 25 are formed in this order, and therefore the anode as the second electrode 25 is disposed as an upper layer than the cathode as the first electrode 22. To make it a top emission type, the cathode as the first electrode 22 may be formed from an electrode material that reflects visible light, and the anode as the second electrode 25 may be formed from an electrode material that transmits visible light, and to make it a bottom emission type, the cathode as the first electrode 22 may be formed from an electrode material that transmits visible light, and the anode as the second electrode 25 may be formed from an electrode material that reflects visible light.

[0091] 9(a) to 9(j) are diagrams illustrating a part of still another process for forming the red light-emitting layer 31R, the green light-emitting layer 31G, and the blue light-emitting layer 31B provided in the display device 1 of the first embodiment.

[0092] 10(a) to 10(j) are diagrams illustrating steps subsequent to the steps illustrated in FIG. 9(a) to FIG. 9(j).

[0093] 11(a) to 11(j) are diagrams showing steps subsequent to the steps shown in FIG. 10(a) to FIG. 10(j).

[0094] In addition, in Figures 9(a) to 9(j), Figures 10(a) to 10(j), and Figures 11(a) to 11(j), the first electrodes 22 provided on the light-emitting elements of each color are omitted.

[0095] The patterning process of the red light emitting quantum dot layer 41R using the lift-off method includes the steps of forming a first photosensitive resin layer 50A on the hole transport layer 30 shown in (a) of FIG. 9, exposing the first photosensitive resin layer 50A through a mask M1 shown in (b) of FIG. 9, developing the first photosensitive resin layer 50A using a developer shown in (c) of FIG. 9 to form an opening in the first photosensitive resin layer 50A, applying a solution containing red light emitting quantum dots shown in (d) of FIG. 9 and heat treating the solution to obtain the red light emitting quantum dot layer 41R, and removing the first photosensitive resin layer 50A using a resist remover shown in (e) of FIG. 9 to obtain a patterned red light emitting quantum dot layer 41R. Here, the case where the red light emitting quantum dot layer 41R is patterned using the lift-off method will be described as an example, but the present invention is not limited to this as long as the red light emitting quantum dot layer 41R can be formed on some of the first electrodes 22 among the plurality of first electrodes 22.

[0096] As shown in (f) and (g) of Figure 9, a photosensitive resin layer formation process was performed in which a second photosensitive resin layer 50B was formed over the entire surface of the red-light-emitting quantum dot layer 41R and the hole transport layer 30. The second photosensitive resin layer 50B was then exposed using a mask M5 and developed, thereby removing the second photosensitive resin layer 50B on a first region, which is a portion of the red-light-emitting quantum dot layer 41R including at least a portion of the end of the red-light-emitting quantum dot layer 41R, and leaving the second photosensitive resin layer 50B on a second region of the red-light-emitting quantum dot layer 41R other than the first region of the red-light-emitting quantum dot layer 41R.

[0097] 9(g), in the patterning step of the second photosensitive resin layer 50B, the second photosensitive resin layer 50B on the first region, which is a part of the red light-emitting quantum dot layer 41R including all the ends of the red light-emitting quantum dot layer 41R, is removed, and the second photosensitive resin layer 50B on the second region of the red light-emitting quantum dot layer 41R other than the first region of the red light-emitting quantum dot layer 41R is left. That is, the second photosensitive resin layer 50B is removed in a frame shape, but the present invention is not limited to this.

[0098] Then, as shown in FIG. 9(h), after the patterning step of the second photosensitive resin layer 50B described above and before the introduction step of the first ligand HL1 shown in FIG. 9(i), a cleaning step for removing the organic ligand OL1 was performed. In this cleaning step, at least a part of the organic ligand OL1 in the first region of the red light-emitting quantum dot layer 41R is removed by an alcohol solution. In this way, by performing the cleaning step for removing the organic ligand OL1 in the first region of the red light-emitting quantum dot layer 41R, the ratio of the organic ligand OL1 in the first region of the red light-emitting quantum dot layer 41R to the first ligand HL1 of the red light-emitting quantum dot layer 41R can be easily adjusted.

[0099] 9(i), a solution containing a first ligand HL1, which is at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, is formed on the first region of the red light-emitting quantum dot layer 41R, and thus a step of incorporating the first ligand HL1 into the red light-emitting quantum dot layer 41R is performed to form the red light-emitting layer 31R. After the step of incorporating the first ligand HL1, a step of removing the solvent (for example, a heat treatment step or a drying step) may be performed as necessary.

[0100] 9(j), after the step of incorporating the first ligand HL1, a step of forming a photosensitive resin material at least on the first region of the red light-emitting layer 31R and forming a second photosensitive resin layer 50B again was performed. In this embodiment, the photosensitive resin material is formed not only on the first region of the red light-emitting layer 31R but also on the entire hole transport layer 30, and the second photosensitive resin layer 50B is formed again, but the present invention is not limited to this.

[0101] The patterning process of the green light-emitting quantum dot layer 41G using the lift-off method includes the steps of forming the second photosensitive resin layer 50B again as shown in (j) of Figure 9 and (a) of Figure 10, exposing the second photosensitive resin layer 50B through a mask M2 as shown in (b) of Figure 10, developing the second photosensitive resin layer 50B using a developer as shown in (c) of Figure 10 to form an opening in the second photosensitive resin layer 50B, applying a solution containing green light-emitting quantum dots as shown in (d) of Figure 10 and heat treating the solution to obtain the green light-emitting quantum dot layer 41G, and removing the second photosensitive resin layer 50B using a resist remover as shown in (e) of Figure 10 to obtain the patterned green light-emitting quantum dot layer 41G. Here, the case where the green light-emitting quantum dot layer 41G is patterned using the lift-off method will be described as an example, but the method is not limited to this as long as the green light-emitting quantum dot layer 41G can be formed on the other part of the first electrodes 22 among the plurality of first electrodes 22.

[0102] As shown in (f) and (g) of FIG. 10, a photosensitive resin layer formation process was performed in which the third photosensitive resin layer 50C was formed over the entire surfaces of the red light-emitting layer 31R, the green light-emitting quantum dot layer 41G, and the hole transport layer 30. The third photosensitive resin layer 50C was then exposed using a mask M6 and developed, thereby removing the third photosensitive resin layer 50C on a first region, which is a portion of the green light-emitting quantum dot layer 41G including at least a portion of the end of the green light-emitting quantum dot layer 41G, and leaving the third photosensitive resin layer 50C on a second region of the green light-emitting quantum dot layer 41G other than the first region of the green light-emitting quantum dot layer 41G.

[0103] 10(g), in the patterning step of the third photosensitive resin layer 50C, the third photosensitive resin layer 50C on the first region, which is a partial region of the green light-emitting quantum dot layer 41G including all of the ends of the green light-emitting quantum dot layer 41G, is removed, and the third photosensitive resin layer 50C on the second region of the green light-emitting quantum dot layer 41G other than the first region of the green light-emitting quantum dot layer 41G is left. That is, the third photosensitive resin layer 50C is removed in a frame shape, but the present invention is not limited to this.

[0104] Then, as shown in Fig. 10(h), after the above-mentioned patterning step of the third photosensitive resin layer 50C and before the introduction step of the first ligand HL2 shown in Fig. 10(i), a cleaning step for removing the organic ligand OL2 was performed. In this cleaning step, at least a part of the organic ligand OL2 in the first region of the green light-emitting quantum dot layer 41G is removed by an alcohol solution. In this way, by performing the cleaning step for removing the organic ligand OL2 in the first region of the green light-emitting quantum dot layer 41G, the ratio of the organic ligand OL2 in the first region of the green light-emitting quantum dot layer 41G to the first ligand HL2 of the green light-emitting quantum dot layer 41G can be easily adjusted.

[0105] Thereafter, as shown in FIG. 10(i), a solution containing a first ligand HL2, which is at least one ligand selected from a ligand made of a halogen atom and a ligand made of a sulfur atom, is formed on the first region of the green light-emitting quantum dot layer 41G, and a process of incorporating the first ligand HL2 into the green light-emitting quantum dot layer 41G is performed to form a green light-emitting layer 31G'. After the process of incorporating the first ligand HL2, a process of removing the solvent (for example, a heat treatment process or a drying process) may be performed as necessary. In this embodiment, the first ligand HL2 incorporated into the green light-emitting quantum dot layer 41G is a different type of ligand from the first ligand HL1 incorporated into the red light-emitting quantum dot layer 41R. In this way, by using different types of ligands, the most preferable type of ligand for the quantum dots contained in the light-emitting layers of each color can be selected.

[0106] 10(j), after the step of incorporating the first ligand HL2, a step of forming a photosensitive resin material at least on the first region of the green light-emitting layer 31G' and forming a third photosensitive resin layer 50C again was performed. In this embodiment, the photosensitive resin material is formed not only on the first region of the green light-emitting layer 31G' but also on the entire hole transport layer 30, and the third photosensitive resin layer 50C is formed again, but the present invention is not limited to this.

[0107] The patterning process of the blue-light-emitting quantum dot layer 41B using the lift-off method includes the steps of forming the third photosensitive resin layer 50C again as shown in FIG. 10(j) and FIG. 11(a), exposing the third photosensitive resin layer 50C through a mask M3 as shown in FIG. 11(b), developing the third photosensitive resin layer 50C using a developing solution as shown in FIG. 11(c) to form an opening in the third photosensitive resin layer 50C, applying a solution containing blue-light-emitting quantum dots as shown in FIG. 11(d) and heat treating the solution to obtain the blue-light-emitting quantum dot layer 41B, and removing the third photosensitive resin layer 50C using a resist remover as shown in FIG. 11(e) to obtain a patterned blue-light-emitting quantum dot layer 41B. Here, an example will be described in which the blue-light-emitting quantum dot layer 41B is patterned using the lift-off method, but this is not limited to this as long as the blue-light-emitting quantum dot layer 41B can be formed on still another part of the first electrodes 22 among the multiple first electrodes 22.

[0108] As shown in (f) and (g) of FIG. 11, a photosensitive resin layer formation process was performed in which a fourth photosensitive resin layer 50D was formed over the entire surfaces of the red light-emitting layer 31R, the green light-emitting layer 31G', the blue light-emitting quantum dot layer 41B, and the hole transport layer 30. The fourth photosensitive resin layer 50D was then exposed using a mask M7 and developed, thereby removing the fourth photosensitive resin layer 50D on a first region, which is a portion of the blue light-emitting quantum dot layer 41B including at least a portion of the end of the blue light-emitting quantum dot layer 41B, and leaving the fourth photosensitive resin layer 50D on a second region of the blue light-emitting quantum dot layer 41B other than the first region of the blue light-emitting quantum dot layer 41B.

[0109] 11(g), in the patterning step of the fourth photosensitive resin layer 50D, the fourth photosensitive resin layer 50D on the first region, which is a part of the blue light-emitting quantum dot layer 41B including all of the ends of the blue light-emitting quantum dot layer 41B, is removed, and the fourth photosensitive resin layer 50D on the second region of the blue light-emitting quantum dot layer 41B other than the first region of the blue light-emitting quantum dot layer 41B is left. That is, the fourth photosensitive resin layer 50D is removed in a frame shape, but the present invention is not limited to this.

[0110] Then, as shown in Fig. 11(h), after the patterning step of the fourth photosensitive resin layer 50D described above and before the introduction step of the first ligand HL3 shown in Fig. 11(i), a cleaning step was performed to remove the organic ligand OL3. In this cleaning step, at least a part of the organic ligand OL3 in the first region of the blue light-emitting quantum dot layer 41B is removed by an alcohol solution. In this way, by performing the cleaning step to remove the organic ligand OL3 in the first region of the blue light-emitting quantum dot layer 41B, the ratio of the organic ligand OL3 in the first region of the blue light-emitting quantum dot layer 41B to the first ligand HL3 of the blue light-emitting quantum dot layer 41B can be easily adjusted.

[0111] Thereafter, as shown in FIG. 11(i), a solution containing a first ligand HL3, which is at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, is formed on the first region of the blue light-emitting quantum dot layer 41B, and a step of incorporating the first ligand HL3 into the blue light-emitting quantum dot layer 41B is performed to form a blue light-emitting layer 31B'. In addition, after the step of incorporating the first ligand HL3, a step of removing the solvent (for example, a heat treatment step or a drying step) may be performed as necessary. In this embodiment, the first ligand HL3 incorporated into the blue light-emitting quantum dot layer 41B is a different type of ligand from the first ligand HL2 incorporated into the green light-emitting quantum dot layer 41G and the first ligand HL1 incorporated into the red light-emitting quantum dot layer 41R. In this way, by using different types of ligands, it is possible to select the most preferable type of ligand for the quantum dots contained in the light-emitting layers of each color.

[0112] Then, as shown in (j) of Figure 11, after the process of incorporating the first ligand HL3, a photosensitive resin layer removal process of removing the fourth photosensitive resin layer 50D is performed, and a red light-emitting layer 31R consisting of the first region 31RR1 and the second region 31RR2, a green light-emitting layer 31G' consisting of the first region 31G'R1 and the second region 31G'R2, and a blue light-emitting layer 31B' consisting of the first region 31B'R1 and the second region 31B'R2 are formed on the hole transport layer 30.

[0113] In the above, an example has been described in which the red light-emitting layer 31R, the green light-emitting layer 31G', and the blue light-emitting layer 31B' are formed in this order, but this is not limited to this, and any color light-emitting layer may be formed first.

[0114] In the manufacturing process of the present embodiment described above, an example has been given in which each photosensitive resin layer is formed from a positive-type photosensitive resin material, taking into consideration ease of peeling, but the present invention is not limited to this.

[0115] [Embodiment 2] Next, a second embodiment of the present invention will be described with reference to Fig. 12 to Fig. 14. A display device 1a of this embodiment differs from the display device 1 described in the first embodiment in that the first region of each color light-emitting layer is composed of multiple sub-regions. The rest is as described in the first embodiment. For ease of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and their explanation will be omitted.

[0116] Figure 12 is a plan view of a red light-emitting layer 31R provided in a red light-emitting element 5R included in a red subpixel RSP of the display device 1a of embodiment 2, a green light-emitting layer 31G provided in a green light-emitting element 5G included in a green subpixel GSP, and a blue light-emitting layer 31B provided in a blue light-emitting element 5B included in a blue subpixel BSP.

[0117] As shown in FIG. 12, the first region 31RR1 of the red light-emitting layer 31R included in the red light-emitting element 5R is composed of a third region 31RR3 and a fourth region 31RR4, which are multiple sub-regions. In this embodiment, the case where the multiple sub-regions are composed of the third region 31RR3 and the fourth region 31RR4 will be described as an example, but the present invention is not limited to this, and the multiple sub-regions may be composed of three or more sub-regions. Two adjacent sub-regions of the multiple sub-regions, that is, the third region 31RR3 and the fourth region 31RR4, are composed of the fourth region 31RR4, which is an inner sub-region provided closer to the second region 31RR2, and the third region 31RR3, which is an outer sub-region provided farther from the second region 31RR2, and the number of the first ligands contained per unit volume of the third region 31RR3, which is the outer sub-region, is greater than the number of the first ligands contained per unit volume of the fourth region 31RR4, which is the inner sub-region. The first region 31GR1 of the green light-emitting layer 31G provided in the green light-emitting element 5G is composed of a third region 31GR3 and a fourth region 31GR4, which are multiple sub-regions. In this embodiment, the case where the multiple sub-regions are composed of the third region 31GR3 and the fourth region 31GR4 will be described as an example, but the present invention is not limited to this, and the multiple sub-regions may be composed of three or more sub-regions. Two adjacent sub-regions of the multiple sub-regions, that is, the third region 31GR3 and the fourth region 31GR4, are composed of the fourth region 31GR4, which is an inner sub-region provided closer to the second region 31GR2, and the third region 31GR3, which is an outer sub-region provided farther from the second region 31GR2, and the number of the first ligands contained per unit volume of the third region 31GR3, which is the outer sub-region, is greater than the number of the first ligands contained per unit volume of the fourth region 31GR4, which is the inner sub-region. Furthermore, the first region 31BR1 of the green light-emitting layer 31B included in the blue light-emitting element 5B is made up of a plurality of sub-regions, that is, a third region 31BR3 and a fourth region 31BR4.In this embodiment, the case where the multiple sub-regions are composed of the third region 31BR3 and the fourth region 31BR4 will be described as an example, but the present invention is not limited thereto, and the multiple sub-regions may be composed of three or more sub-regions. Two adjacent sub-regions of the multiple sub-regions, i.e., the third region 31BR3 and the fourth region 31BR4, are composed of the fourth region 31BR4, which is an inner sub-region provided closer to the second region 31BR2, and the third region 31BR3, which is an outer sub-region provided farther from the second region 31BR2, and the number of the first ligands contained per unit volume of the third region 31BR3, which is the outer sub-region, is greater than the number of the first ligands contained per unit volume of the fourth region 31BR4, which is the inner sub-region. Therefore, the number of the first ligands contained per unit volume in the second region 31RR2 of the red light-emitting layer 31R is smaller than the number of the first ligands contained per unit volume in the fourth region 31RR4 of the red light-emitting layer 31R, and the number of the first ligands contained per unit volume in the fourth region 31RR4 of the red light-emitting layer 31R is smaller than the number of the first ligands contained per unit volume in the third region 31RR3 of the red light-emitting layer 31R. Also, the number of the first ligands contained per unit volume in the second region 31GR2 of the green light-emitting layer 31G is smaller than the number of the first ligands contained per unit volume in the fourth region 31GR4 of the green light-emitting layer 31G, and the number of the first ligands contained per unit volume in the fourth region 31GR4 of the green light-emitting layer 31G is smaller than the number of the first ligands contained per unit volume in the third region 31GR3 of the green light-emitting layer 31G. Furthermore, the number of the first ligands contained per unit volume in the second region 31BR2 of the blue light-emitting layer 31B is smaller than the number of the first ligands contained per unit volume in the fourth region 31BR4 of the blue light-emitting layer 31B, and the number of the first ligands contained per unit volume in the fourth region 31BR4 of the blue light-emitting layer 31B is smaller than the number of the first ligands contained per unit volume in the third region 31BR3 of the blue light-emitting layer 31B.According to this configuration, in each color-emitting layer, the number of the first ligands contained per unit volume in the fourth region, which is less affected by impurities, etc., is reduced compared to the third region, which is more affected by the impurities, etc., and thus, compared to the above-mentioned first embodiment in which the number of the first ligands contained per unit volume of the entire first region is the same, it is possible to efficiently provide stronger protection for the quantum dots (QDs) in the third region of each color-emitting layer than for the quantum dots (QDs) in the fourth region.

[0118] Furthermore, each of the red light-emitting layer 31R, the green light-emitting layer 31G, and the blue light-emitting layer 31B may contain, at least in part, a second ligand that is a ligand other than the first ligand. In this embodiment, for example, an organic ligand made of an organic molecule having a certain length is used as the second ligand in order to prevent aggregation of quantum dots (QDs), but the present invention is not limited to this.

[0119] As shown in Figure 12, the third region 31RR3 and the fourth region 31RR4 of the red light-emitting layer 31R are composed of the fourth region 31RR4, which is an inner sub-region located closer to the second region 31RR2, and the third region 31RR3, which is an outer sub-region located farther from the second region 31RR2, and the ratio of the number of the first ligands in the third region 31RR3 to the total number of ligands in the third region 31RR3, which is the sum of the number of the first ligands in the third region 31RR3 and the number of the second ligands in the third region 31RR3, is greater than the ratio of the number of the first ligands in the fourth region 31RR4 to the total number of ligands in the fourth region 31RR4, which is the sum of the number of the first ligands in the fourth region 31RR4 and the number of the second ligands in the fourth region 31RR4. In addition, the third region 31GR3 and the fourth region 31GR4 of the green light-emitting layer 31G are composed of the fourth region 31GR4, which is an inner sub-region located closer to the second region 31GR2, and the third region 31GR3, which is an outer sub-region located farther from the second region 31GR2, and the ratio of the number of the first ligands in the third region 31GR3 to the total number of ligands in the third region 31GR3, which is the sum of the number of the first ligands in the third region 31GR3 and the number of the second ligands in the third region 31GR3, is greater than the ratio of the number of the first ligands in the fourth region 31GR4 to the total number of ligands in the fourth region 31GR4, which is the sum of the number of the first ligands in the fourth region 31GR4 and the number of the second ligands in the fourth region 31GR4. Furthermore, the third region 31BR3 and the fourth region 31BR4 of the blue light-emitting layer 31B are composed of the fourth region 31BR4 which is an inner sub-region located closer to the second region 31BR2, and the third region 31BR3 which is an outer sub-region located farther from the second region 31BR2, and the ratio of the number of the first ligands in the third region 31BR3 to the total number of ligands in the third region 31BR3, which is the sum of the number of the first ligands in the third region 31BR3 and the number of the second ligands in the third region 31BR3, is greater than the ratio of the number of the first ligands in the fourth region 31BR4 to the total number of ligands in the fourth region 31BR4, which is the sum of the number of the first ligands in the fourth region 31BR4 and the number of the second ligands in the fourth region 31BR4.

[0120] It is preferable that the ratio of the number of fluorine, which is the first ligand, to the total number of ligands per quantum dot (QD) contained in the second region 31RR2 of the red light-emitting layer 31R is 0% or more and 82% or less, it is preferable that the ratio of the number of fluorine, which is the first ligand, to the total number of ligands per quantum dot (QD) contained in the fourth region 31RR4 of the red light-emitting layer 31R is greater than 82% and 90% or less, and it is preferable that the ratio of the number of fluorine, which is the first ligand, to the total number of ligands per quantum dot (QD) contained in the third region 31RR3 of the red light-emitting layer 31R is greater than 90% and 100% or less. In addition, the ratio of the number of fluorine as the first ligand to the total number of ligands per quantum dot (QD) included in the second region 31GR2 of the green light-emitting layer 31G is preferably 0% or more and 82% or less, the ratio of the number of fluorine as the first ligand to the total number of ligands per quantum dot (QD) included in the fourth region 31GR4 of the green light-emitting layer 31G is preferably greater than 82% and 90% or less, and the ratio of the number of fluorine as the first ligand to the total number of ligands per quantum dot (QD) included in the third region 31GR3 of the green light-emitting layer 31G is preferably greater than 90% and 100% or less. Furthermore, the ratio of the number of fluorine as the first ligand to the total number of ligands per quantum dot (QD) included in the second region 31BR2 of the blue light-emitting layer 31B is preferably 0% or more and 82% or less, the ratio of the number of fluorine as the first ligand to the total number of ligands per quantum dot (QD) included in the fourth region 31BR4 of the blue light-emitting layer 31B is preferably greater than 82% and 90% or less, and the ratio of the number of fluorine as the first ligand to the total number of ligands per quantum dot (QD) included in the third region 31BR3 of the blue light-emitting layer 31B is preferably greater than 90% and 100% or less.According to this configuration, by reducing the proportion of the first ligand in the fourth region, which is less affected by impurities, in each color-emitting layer, compared to the third region, which is more affected by impurities, etc., it is possible to efficiently provide stronger protection for the quantum dots (QDs) in the third region of each color-emitting layer than for the quantum dots (QDs) in the fourth region while reducing the amount of the first ligand, compared to the above-mentioned first embodiment, in which the proportion of the first ligand in the entire first region is equal.

[0121] As described above in the first embodiment, the width of the first region, i.e., the width of the peripheral portion, is preferably 1 μm or more and 4 μm or less, and therefore the combined width of the third region and the fourth region is preferably 2 μm or more and 4 μm or less. The width of the third region and the width of the fourth region may be approximately the same.

[0122] Hereinafter, a process for forming a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device 1a of the second embodiment will be described with reference to FIGS.

[0123] FIGS. 13(a) to 13(e) are diagrams illustrating a part of a process for forming a light-emitting layer provided in a light-emitting element included in each sub-pixel of the display device 1a of the second embodiment.

[0124] FIG. 13(a) is the same as FIG. 7(d) and shows the state after the step of incorporating the first ligand HL1 into the red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the blue-light-emitting quantum dot layer 41B.

[0125] 13(b), a photosensitive resin material is formed at least on the first region of the red light-emitting quantum dot layer 41R, the first region of the green light-emitting quantum dot layer 41G, and the first region of the blue light-emitting quantum dot layer 41B, and a photosensitive resin layer 40D is formed again. The photosensitive resin layer 40D is exposed using a mask M8. In this embodiment, a photosensitive resin material is formed not only on the first region of the red light-emitting quantum dot layer 41R, the first region of the green light-emitting quantum dot layer 41G, and the first region of the blue light-emitting quantum dot layer 41B, but also on the entire hole transport layer 30, and a photosensitive resin layer 40D is formed again, but the present invention is not limited to this.

[0126] Then, by developing, as shown in (c) of Fig. 13, the photosensitive resin layer 40D was removed from a part of the red light-emitting quantum dot layer 41R including the first region of the red light-emitting quantum dot layer 41R and wider than the first region of the red light-emitting quantum dot layer 41R, a part of the green light-emitting quantum dot layer 41G including the first region of the green light-emitting quantum dot layer 41G and wider than the first region of the green light-emitting quantum dot layer 41G, and a part of the blue light-emitting quantum dot layer 41B including the first region of the blue light-emitting quantum dot layer 41B and wider than the first region of the blue light-emitting quantum dot layer 41B. In this embodiment, as shown in (c) of Fig. 13, the photosensitive resin layer 40D was removed in a frame shape, but is not limited thereto.

[0127] Then, as shown in (d) of Figure 13, a washing step was performed to remove the organic ligands OL1, OL2, and OL3 before the step of further incorporating the first ligand HL1 shown in (e) of Figure 13. Note that the first ligand HL1 already coordinated to the quantum dots (QDs) is not removed at this time because of its strong coordination force with the quantum dots (QDs). In this way, by performing a washing step to remove the organic ligands OL1, OL2, and OL3, the ratio of the organic ligands OL1, OL2, and OL3 to the first ligand HL1 in the fourth region can be easily adjusted.

[0128] Then, as shown in FIG. 13(e), a step of further incorporating the first ligand HL1 was performed. In this embodiment, a solution containing the first ligand HL1, which is at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, was formed on a region including at least a part of the end of the red light-emitting quantum dot layer 41R and different from the first region of the red light-emitting quantum dot layer 41R, on a region including at least a part of the end of the green light-emitting quantum dot layer 41G and different from the first region of the green light-emitting quantum dot layer 41G, and on a region including at least a part of the end of the blue light-emitting quantum dot layer 41B and different from the first region of the blue light-emitting quantum dot layer 41B, thereby performing a step of further incorporating the first ligand HL1. In addition, after the step of further incorporating the first ligand HL1, a step of removing the solvent (for example, a heat treatment step or a drying step) may be performed as necessary. The content of the first ligand HL1 in the solution is within a range in which the first ligand HL1 can be dissolved or dispersed in the solvent used, and can be appropriately determined in consideration of the amount of the first ligand HL1 to be incorporated.

[0129] Thereafter, although not shown, a photosensitive resin layer removal process is performed to remove the photosensitive resin layer 40D, and a red light-emitting layer 31R consisting of the second region 31RR2, the third region 31RR3, and the fourth region 31RR4, a green light-emitting layer 31G consisting of the second region 31GR2, the third region 31GR3, and the fourth region 31GR4, and a blue light-emitting layer 31B consisting of the second region 31BR2, the third region 31BR3, and the fourth region 31BR4 are formed on the hole-transport layer 30.

[0130] In this embodiment, in the step of further incorporating the first ligand HL1, the first ligand HL1 is further incorporated in a region that includes the first region as a region different from the first region of each color light-emitting quantum dot layer and is wider than the first region, so that the first region including the third region and the fourth region is expanded, but is not limited to this. For example, in the step of further incorporating the first ligand HL1, the first ligand HL1 may be further incorporated in a region that includes at least a part of the end of each color light-emitting quantum dot layer as a region different from the first region of each color light-emitting quantum dot layer and in a part of the first region.

[0131] According to the above-mentioned manufacturing method, the steps shown in FIG. 13(a) to FIG. 13(e) are performed on the entire red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G, and the blue-light-emitting quantum dot layer 41B formed by the method shown in FIG. 6, so that the number of manufacturing steps can be reduced.

[0132] FIGS. 14(a) to 14(e) are diagrams illustrating a part of still another process for forming the light-emitting layer provided in the light-emitting element included in each sub-pixel of the display device 1a of the second embodiment.

[0133] FIG. 14(a) is the same as FIG. 9(j), and shows a state in which, after a process of incorporating a first ligand HL1 into the red-light-emitting quantum dot layer 41R, a photosensitive resin material is formed on the first region of the red-light-emitting quantum dot layer 41R, and then a process of forming a second photosensitive resin layer 50B is again performed.

[0134] Thereafter, as shown in (b) and (c) of Fig. 14, the second photosensitive resin layer 50B was exposed using a mask M9 and developed to remove the second photosensitive resin layer 50B on a partial region of the red light-emitting quantum dot layer 41R that includes the first region of the red light-emitting quantum dot layer 41R and is wider than the first region of the red light-emitting quantum dot layer 41R. In this embodiment, as shown in (c) of Fig. 14, the second photosensitive resin layer 50B was removed in a frame shape, but is not limited thereto.

[0135] Then, as shown in (d) of Figure 14, a washing step was performed to remove the organic ligands OL1, OL2, and OL3 before the step of further incorporating the first ligand HL1 shown in (e) of Figure 14. Note that the first ligand HL1 already coordinated to the quantum dots (QDs) is not removed at this time because of its strong coordination force with the quantum dots (QDs). In this way, by performing a washing step to remove the organic ligands OL1, OL2, and OL3, the ratio of the organic ligands OL1, OL2, and OL3 to the first ligand HL1 in the fourth region can be easily adjusted.

[0136] Then, as shown in FIG. 14(e), a step of further incorporating the first ligand HL1 was performed. In this embodiment, a solution containing the first ligand HL1, which is at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, was formed on a region that includes at least a part of the end of the red light-emitting quantum dot layer 41R and is different from the first region of the red light-emitting quantum dot layer 41R, thereby performing a step of further incorporating the first ligand HL1. In addition, after the step of further incorporating the first ligand HL1, a step of removing the solvent (for example, a heat treatment step or a drying step) may be performed as necessary. The content of the first ligand HL1 in the solution is within a range that allows the first ligand HL1 to be dissolved or dispersed in the solvent used, and can be appropriately determined in consideration of the amount of the first ligand HL1 to be incorporated.

[0137] Thereafter, although not shown, a step of forming a second photosensitive resin layer 50B is carried out again, and then the steps shown in FIGS. 10 and 11 can be carried out.

[0138] Here, the step of further incorporating the first ligand HL1 has been described based on Fig. 14, but the present invention is not limited thereto, and after the step shown in Fig. 10(i), a step of further incorporating the first ligand HL2 into the green light-emitting quantum dot layer 41G can be performed similarly to Fig. 14, and after the step shown in Fig. 11(i), a step of further incorporating the first ligand HL3 into the blue light-emitting quantum dot layer 41B can be performed similarly to Fig. 14. In this embodiment, the first ligand HL1, the first ligand HL2, and the first ligand HL3 are different types of ligands, so that the most preferable type of ligand for the quantum dots contained in the light-emitting layer of each color can be selected.

[0139] [Embodiment 3] Next, a third embodiment of the present invention will be described with reference to FIG. 15. In the display device 1b of this embodiment, the first region of each of the red light-emitting layer 31R, the green light-emitting layer 31G, and the blue light-emitting layer 31B is composed of a first island-shaped portion including one of the two opposing ends of the light-emitting layer of each color, and a second island-shaped portion including the other of the two opposing ends of the light-emitting layer of each color, and the second region is sandwiched between the first island-shaped portion and the second island-shaped portion, which is different from the display devices described in the first and second embodiments. The rest is as described in the first and second embodiments. For convenience of explanation, the same reference numerals are used for members having the same functions as the members shown in the drawings of the first and second embodiments, and their explanations are omitted.

[0140] FIG. 15 is a plan view of a light-emitting layer provided in a light-emitting element included in each sub-pixel of a display device 1b of the third embodiment.

[0141] As shown in FIG. 15, the first region 31RR1 of the red light-emitting layer 31R provided in the red light-emitting element 5R included in the red subpixel RSP is composed of a first island-shaped portion including one of the two opposing ends 31REL and 31RER of the red light-emitting layer 31R and a second island-shaped portion including the other of the two opposing ends 31REL and 31RER of the red light-emitting layer 31R, and the second region 31RR2 of the red light-emitting layer 31R is sandwiched between the first island-shaped portion and the second island-shaped portion. The first region 31GR1 of the green light-emitting layer 31G included in the green light-emitting element 5G included in the green subpixel GSP is composed of a first island-shaped portion including one of the two opposing ends 31GEL and 31GER of the green light-emitting layer 31G and a second island-shaped portion including the other of the two opposing ends 31GEL and 31GER of the green light-emitting layer 31G, and the second region 31GR2 of the green light-emitting layer 31G is sandwiched between the first island-shaped portion and the second island-shaped portion. The first region 31BR1 of the blue light-emitting layer 31B included in the blue light-emitting element 5B included in the blue subpixel BSP is composed of a first island-shaped portion including one of the two opposing ends 31BEL and 31BER of the blue light-emitting layer 31B and a second island-shaped portion including the other of the two opposing ends 31BEL and 31BER of the blue light-emitting layer 31B, and the second region 31BR2 of the blue light-emitting layer 31B is sandwiched between the first island-shaped portion and the second island-shaped portion. In this embodiment, the two opposing ends of the light-emitting layer of each color are described as the right end and the left end in the figure as an example, but this is not limited to this, and the two opposing ends of the light-emitting layer of each color may be the upper end and the lower end in the figure.

[0142] By adopting such a configuration, it is possible to realize a light-emitting element and a display device that can further improve the light-emitting characteristics of the light-emitting layer while protecting the quantum dots around the light-emitting layer, i.e., ensuring reliability, compared to the above-mentioned first and second embodiments.

[0143] Each color light-emitting layer provided in the display device 1b shown in FIG. 15 can be formed by performing the steps shown in FIG. 7(c), FIG. 7(d) and FIG. 7(e) in a patterning process of the photosensitive resin layer 40D shown in FIG. 7(a) and FIG. 7(b), in which the photosensitive resin layer 40D on a first region consisting of a first island-shaped portion including one of two opposing ends of each of the red-light-emitting quantum dot layer 41R, the green-light-emitting quantum dot layer 41G and the blue-light-emitting quantum dot layer 41B and a second island-shaped portion including the other of the two opposing ends is removed, and the photosensitive resin layer 40D on a second region other than the first region is left.

[0144] [Embodiment 4] Next, a fourth embodiment of the present invention will be described with reference to FIG. 16. In the display device 1c of this embodiment, only the first region of the blue light-emitting layer 31B is composed of a first island-shaped portion including one of the two opposing ends of the blue light-emitting layer 31B and a second island-shaped portion including the other of the two opposing ends of the blue light-emitting layer 31B, and the second region of the blue light-emitting layer 31B is sandwiched between the first island-shaped portion and the second island-shaped portion, which is different from the display device described in the third embodiment. The rest is as described in the third embodiment. For convenience of explanation, the same reference numerals are used for members having the same functions as the members shown in the drawings of the third embodiment, and their explanations are omitted.

[0145] FIG. 16 is a plan view of a light-emitting layer provided in a light-emitting element included in each sub-pixel of a display device 1c of the fourth embodiment.

[0146] 16, the first region 31BR1 of the blue light-emitting layer 31B included in the blue light-emitting element 5B included in the blue subpixel BSP is composed of a first island-shaped portion including one of the two opposing ends 31BEL and 31BER of the blue light-emitting layer 31B and a second island-shaped portion including the other of the two opposing ends 31BEL and 31BER of the blue light-emitting layer 31B, and the second region 31BR2 of the blue light-emitting layer 31B is sandwiched between the first island-shaped portion and the second island-shaped portion. Note that, in the present embodiment, the two opposing ends of the blue light-emitting layer 31B are the right end and the left end in the figure as an example, but the present invention is not limited to this, and the two opposing ends of the blue light-emitting layer 31B may be the upper end and the lower end in the figure.

[0147] As shown in FIG. 16, the red light-emitting layer 61R provided in the red light-emitting element 5R included in the red sub-pixel RSP and the green light-emitting layer 61G provided in the green light-emitting element 5G included in the green sub-pixel GSP are conventional light-emitting layers that do not have the first and second regions described above.

[0148] By adopting such a configuration, it is possible to ensure the reliability of the blue light-emitting layer, which is less reliable than the red and green light-emitting layers, and it is possible to realize a display device in which the light-emitting characteristics of the red and green light-emitting layers are sufficiently ensured.

[0149] In this embodiment, an example has been described in which the first region 31BR1 and the second region 31BR2 are provided only in the blue light-emitting layer 31B, but this is not limited to this, and the first region 31RR1 and the second region 31RR2 may be provided only in the red light-emitting layer 31R, or the first region 31GR1 and the second region 31GR2 may be provided only in the green light-emitting layer 31G.

[0150] [Additional Notes] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. The technical scope of the present invention also includes embodiments obtained by appropriately combining the technical means disclosed in the different embodiments. Furthermore, new technical features can be formed by combining the technical means disclosed in the respective embodiments. [Industrial Applicability]

[0151] The present invention can be utilized in a light-emitting element, a display device, a method for manufacturing a light-emitting element, and a method for manufacturing a display device. [Explanation of symbols]

[0152] 1 Display device 3. Barrier layer 4 Thin Film Transistor Layer 5B, 5B' Blue light emitting element (first light emitting element) 5G Green light-emitting element (second light-emitting element) 5R Red light emitting element (third light emitting element) 6 Sealing layer 12 Substrate 16, 18, 20 Inorganic insulating film 21 Planarization film 22 1st electrode 23 Bank 24R Functional layer including red light-emitting layer 24G Functional layer including green light-emitting layer 24B Functional layer including blue light-emitting layer 25 2nd electrode 26, 28 Inorganic sealing film 27 Organic film 30 Hole transport layer 31B Blue light-emitting layer (light-emitting layer) 31BR1 First region (periphery) of blue light-emitting layer 31BR2 Second region of blue light-emitting layer (center) 31BR1H Width of the first region of the blue light-emitting layer (peripheral width) 31BR2H Width of the second region of the blue light-emitting layer (center width) 31BET Top end of blue light-emitting layer (end of light-emitting layer) 31BER Right end of the blue light-emitting layer (end of the light-emitting layer) 31BEL Left end of blue light-emitting layer (end of light-emitting layer) 31BEB Bottom end of blue light-emitting layer (end of light-emitting layer) 31G Green light-emitting layer (light-emitting layer) 31GR1 First region of green light-emitting layer 31GR2 Second region of green light-emitting layer 31GET Top end of green light-emitting layer (end of light-emitting layer) 31GER Right end of the green light-emitting layer (end of the light-emitting layer) 31GEL Left end of the green light-emitting layer (end of the light-emitting layer) 31GEB Bottom end of the green light-emitting layer (end of the light-emitting layer) 31R Red light-emitting layer (light-emitting layer) 31RR1 Red light-emitting layer first region 31RR2 Second region of red light-emitting layer 31RET Top end of red light-emitting layer (end of light-emitting layer) 31RER Right end of the red light-emitting layer (end of the light-emitting layer) 31REL Left end of the red light-emitting layer (end of the light-emitting layer) 31REB Bottom end of the red light-emitting layer (end of the light-emitting layer) 32 Electron transport layer 39 Functional Film 40A 1st photosensitive resin layer 40B 2nd photosensitive resin layer 40C 3rd photosensitive resin layer 40D photosensitive resin layer 41R Red light emitting quantum dot layer (first quantum dot layer) 41G Green light-emitting quantum dot layer (second quantum dot layer) 41B Blue light-emitting quantum dot layer (third quantum dot layer) 50A 1st photosensitive resin layer 50B 2nd photosensitive resin layer 50C 3rd photosensitive resin layer 50D 4th photosensitive resin layer HL1, HL2, HL3 1st Ligand OL1, OL2, OL3 Secondary ligand (organic ligand) PIX RSP Red sub-pixel GSP Green sub-pixel BSP Blue subpixel TR Transistor SEM, SEM', SEM'' Semiconductor Film G gate electrode D drain electrode S source electrode DA display area NDA Frame Area

Claims

1. A first electrode and a second electrode; a functional layer disposed between the first electrode and the second electrode and having at least a light-emitting layer including quantum dots; the light-emitting layer at least partially contains a first ligand, which is at least one ligand selected from a ligand consisting of a halogen atom and a ligand consisting of a sulfur atom, and the light-emitting layer comprises a first region which is a partial region of the light-emitting layer including at least a part of an edge of the light-emitting layer, and a second region other than the first region; A light-emitting device, wherein the number of the first ligands contained per unit volume of the first region is greater than the number of the first ligands contained per unit volume of the second region.

2. The light-emitting device according to claim 1 , wherein the first ligand is contained in the first region and the second region of the light-emitting layer.

3. The light-emitting device according to claim 1 , wherein the first ligand is contained only in the first region of the light-emitting layer.

4. The light-emitting device according to claim 1 , wherein the light-emitting layer includes a second ligand that is a ligand other than the first ligand.

5. the light-emitting layer includes a second ligand that is a ligand other than the first ligand; the second ligand type includes organic ligands; The light-emitting device according to claim 1 , wherein the organic ligand is contained in the first region and the second region of the light-emitting layer.

6. The light-emitting element according to claim 5 , wherein the number of the second ligands contained per unit volume of the second region is greater than the number of the second ligands contained per unit volume of the first region.

7. the second ligand is an organic ligand; 6. The light-emitting element according to claim 5, wherein a ratio of the number of the first ligands in the first region to a total number of ligands in the first region, which is a sum of the number of the first ligands in the first region and the number of the organic ligands in the first region, is greater than a ratio of the number of the first ligands in the second region to a total number of ligands in the second region, which is a sum of the number of the first ligands in the second region and the number of the organic ligands in the second region.

8. the first region is composed of a first island-shaped portion including one of two opposing ends of the light-emitting layer and a second island-shaped portion including the other of the two opposing ends of the light-emitting layer; The light-emitting element according to claim 1 , wherein the second region is sandwiched between the first island portion and the second island portion.

9. the first region is a partial region of the light-emitting layer including an entire end portion of the light-emitting layer, The light-emitting element according to claim 1 , wherein the second region is surrounded by the first region.

10. The first region is composed of a plurality of sub-regions, Two adjacent sub-regions of the plurality of sub-regions are composed of an inner sub-region provided closer to the second region and an outer sub-region provided farther from the second region, The light-emitting device according to claim 1 , wherein the number of the first ligands contained per unit volume of the outer subregion is greater than the number of the first ligands contained per unit volume of the inner subregion.

11. the light-emitting layer includes a second ligand that is a ligand other than the first ligand; The first region is composed of a plurality of sub-regions, Two adjacent sub-regions of the plurality of sub-regions are composed of an inner sub-region provided closer to the second region and an outer sub-region provided farther from the second region, 10. The light-emitting device according to claim 1 , wherein a ratio of the number of first ligands in the outer subregion to a total number of ligands in the outer subregion, which is the sum of the number of first ligands in the outer subregion and the number of second ligands in the outer subregion, is greater than a ratio of the number of first ligands in the inner subregion to a total number of ligands in the inner subregion, which is the sum of the number of first ligands in the inner subregion and the number of second ligands in the inner subregion.

12. The light-emitting element according to claim 1 , wherein the first ligand is a ligand formed of a halogen atom.

13. The light-emitting element according to claim 1 , wherein a ratio of an area of ​​the first region to an area of ​​the light-emitting layer is equal to or greater than 8.5% and equal to or less than 33%.

14. The light-emitting element according to claim 1 , wherein a width of the first region, which is the shortest distance from an end of the light-emitting layer to the second region, is 1 μm or more.

15. 15. The light-emitting element according to claim 1, wherein a width of the first region, which is the shortest distance from an end of the light-emitting layer to the second region, is 4 [mu]m or less.

16. The light-emitting device according to claim 1 , wherein the first ligand is fluorine.

17. A display device comprising the light-emitting element according to claim 1 .

18. A first light-emitting element which is the light-emitting element; A second light emitting element having an emission peak wavelength longer than the emission peak wavelength of the first light emitting element; The display device according to claim 17 , further comprising: a third light-emitting element having an emission peak wavelength longer than the emission peak wavelength of the second light-emitting element.

19. the light emitting layer of the first light emitting element includes the first region and the second region, the first region is composed of a first island-shaped portion including one of two opposing ends of the light-emitting layer and a second island-shaped portion including the other of the two opposing ends of the light-emitting layer; The display device according to claim 18 , wherein the second region is sandwiched between the first island portion and the second island portion.

Images