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

Abstract

In the present invention, a second region (7) has a first area (10) connected a first contour portion (8) and a second area (11) connected to a second contour portion (9), and the second area (11) includes a crack (12).

Description

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

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

[0002] Patent Document 1 discloses a method for manufacturing a quantum dot structure, in which quantum dots are formed in a matrix.

[0003] Japanese Patent Publication No. 2013-051318

[0004] In the technique disclosed in Patent Document 1, cracks may occur in the matrix in the light-emitting region, and the quantum dot structure may float in the light-emitting region, which may result in a decrease in light-emitting efficiency.

[0005] A light-emitting element according to one aspect of the present disclosure comprises a lower electrode, an upper electrode, and a functional layer located above the lower electrode and below the upper electrode, the functional layer containing an inorganic matrix; in a planar view, the functional layer has a first region located in the light-emitting region, and a second region located outside the first region and connected to the first region; in the planar view, the periphery of the first region includes a first outer shape portion having a first curvature and a second outer shape portion having a second curvature larger than the first curvature; the second region has a first portion connected to the first outer shape portion and a second portion connected to the second outer shape portion, the second portion including a crack.

[0006] According to one aspect of the present disclosure, a decrease in luminous efficiency can be suppressed.

[0007] 9 is a cross-sectional view showing a schematic configuration of a light-emitting device according to embodiment 1 of the present disclosure. FIG. 10 is a plan view of a functional layer according to embodiment 1 of the present disclosure. FIG. 11 shows mathematical formula (1). FIG. 12 is a plan view of another functional layer according to embodiment 1 of the present disclosure. FIG. 13 is an explanatory diagram of a second outer portion. FIG. 14 is a cross-sectional view taken along line A-A in FIG. 2. FIG. 15 is a cross-sectional view taken along line B-B in FIG. 2. FIG. 16 is an enlarged view of range C in FIG. 2. FIG. 17 is a plan view of a functional layer and a partition wall according to embodiment 2 of the present disclosure. FIG. 18 is a cross-sectional view taken along line C-C in FIG. 19. FIG. 19 is a cross-sectional view taken along line D-D in FIG. 19. FIG. 19 is a diagram illustrating a first example of a method for forming a functional layer. FIG. 19 is a diagram illustrating a second example of a method for forming a functional layer. FIG. 19 is a flowchart illustrating an outline of a method for manufacturing a light-emitting device according to embodiment 5 of the present disclosure. FIG. 19 is a diagram illustrating a specific example of step Sb. FIG. 19 is a diagram illustrating unevenness on the upper surface of a partition wall. FIG. 19 is another diagram illustrating unevenness on the upper surface of a partition wall.

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes an embodiment of the present disclosure. For convenience of explanation, the same reference numerals are used to designate components having the same functions as those previously described, and the description thereof may not be repeated.

[0009] [Embodiment 1] Fig. 1 is a cross-sectional view showing a schematic configuration of a light-emitting element 101 according to embodiment 1 of the present disclosure. The light-emitting element 101 includes a lower electrode 1, an upper electrode 2, and a functional layer 3. The functional layer 3 is located above the lower electrode 1 and below the upper electrode 2. The functional layer 3 includes an inorganic matrix 4. Fig. 1 is a diagram intended to simply show that the light-emitting element 101 includes the lower electrode 1 and the upper electrode 2. Components that are not directly related to this purpose are omitted from Fig. 1. That is, components other than the lower electrode 1, the upper electrode 2, and the layers located between the lower electrode 1 and the upper electrode 2 are omitted from Fig. 1.

[0010] The functional layer 3 may be formed as, for example, a light-emitting layer 15. The light-emitting layer 15 may emit light by a current flowing between the lower electrode 1 and the upper electrode 2. Examples of the light-emitting layer 15 include an organic light-emitting diode (OLED) layer and a quantum light-emitting diode (QLED) layer. The functional layer 3 may have a plurality of quantum dots 16, with the inorganic matrix 4 filling the spaces between the plurality of quantum dots 16. On the other hand, the functional layer 3 is not limited to the light-emitting layer 15, and may be a layer separate from the light-emitting layer 15 that satisfies the configuration requirements of the functional layer 3.

[0011] The inorganic matrix 4 may contain a plurality of quantum dots 16. Here, containing means that the inorganic matrix 4 covers a part or all of the surface of each of the plurality of quantum dots 16, for example. The inorganic matrix 4 may be a single film that is not separated by a material other than the inorganic matrix 4. In addition, the inorganic matrix 4 may be a single film having an area of ​​1000 nm 2 or less in a plan view of the light-emitting element 101. ２ The inorganic matrix 4 may be formed in the above-described manner, or may be an integrated film in which the materials constituting the inorganic matrix 4 are seamlessly connected by chemical bonds. The inorganic matrix 4 is formed, for example, so as to partially or completely fill the spaces formed between the quantum dots 16 contained in the inorganic matrix 4. There may be voids in the functional layer 3. The quantum dots 16 contained in the inorganic matrix 4 may be present at intervals from one another. The inorganic matrix 4 may contain an inorganic substance. In particular, the inorganic matrix 4 may contain a metal sulfide, a metal oxide, or a metal halide. The inorganic matrix 4 may also contain at least one of a II-VI compound, a group II oxide, a group III oxide, and a group IV oxide. The inorganic matrix 4 may be formed, for example, of silicon oxide (SiO ２ ), and zinc sulfide (ZnS). Alternatively, the inorganic matrix 4 may contain, for example, titanium oxide (TiO ２ ), aluminum oxide (Al ２ O ３ ), boron oxide (B ２ O ３ ), phosphorus oxide (P２ O ５ ), germanium oxide (GeO ２ ), hafnium oxide (HfO ２ ), zinc oxide (ZnO), zirconium oxide (ZrO ２ ), tellurium oxide (TeO ２ ), bismuth oxide (Bi ２ O ３ ), vanadium oxide (V ２ O ５ ), antimony oxide (Sb ２ O ５ ), lead oxide (PbO), copper oxide (CuO), copper(I) iodide (CuI), and silver(I) iodide (AgI). The chemical formulas in parentheses after the compound names are representative examples. The composition ratios described in the chemical formulas may be stoichiometric, but do not necessarily have to be stoichiometric.

[0012] The lower electrode 1 may be an anode of the light-emitting element 101. An example of a material for the lower electrode 1 is ITO (Indium Tin Oxide). The upper electrode 2 may be a cathode of the light-emitting element 101. An example of a material for the upper electrode 2 is Ag.

[0013] The light-emitting element 101 may optionally include at least one of a hole injection layer 51, a hole transport layer 52, an electron transport layer 53, and an electron injection layer between the lower electrode 1 and the upper electrode 2. Hereinafter, any one of the hole injection layer 51, the hole transport layer 52, the electron transport layer 53, and the electron injection layer may be referred to as an underlayer. FIG. 1 shows a light-emitting region 5 of the light-emitting element 101.

[0014] Fig. 2 is a plan view of the functional layer 3 according to the first embodiment of the present disclosure. Fig. 3 shows the formula (1).

[0015] In a plan view, the functional layer 3 has a first region 6 and a second region 7. Specifically, the plan view is a plan view of the light-emitting element 101. The first region 6 is located in the light-emitting region 5. The second region 7 is located outside the first region 6. The second region 7 is connected to the first region 6.

[0016] In a plan view, the periphery of the first region 6 includes a first outer shape portion 8 and a second outer shape portion 9. The first outer shape portion 8 has a first curvature. The second outer shape portion 9 has a second curvature. The second curvature is larger than the first curvature. The curvature is defined as the reciprocal of the radius of curvature R. The radius of curvature R is calculated by the following formula (1). The unit of the curvature is 1 / m (m －１ The first curvature is 0 / m or more and 1.5×10 ３ The second curvature may be less than 1.5×10 ３ / m or more and 3.1 × 10 ５ / m or less.

[0017] The second region 7 has a first portion 10 and a second portion 11. The second portion 11 may include a region 11a connected to the second outer periphery 9 and a surrounding region 11b. The first portion 10 is mainly a region connected to the first outer periphery 8. The width L1 of the first portion 10 may be, for example, 0.5 μm or more and 50 μm or less. The width L2 of the second portion 11 may be the same as the width L1. The region 11a in the second portion 11 may be a region surrounded by the second outer periphery 9, straight lines perpendicular to the first outer periphery 8 at each end of the second outer periphery 9 (for example, point E where the first outer periphery 8 and the second outer periphery 9 meet), and the outermost periphery of the second region 7. The surrounding region 11b in the second portion 11 may be, for example, a region surrounded by a portion connecting point E where the first external portion 8 and the second external portion 9 meet in the first external portion 8 and a point L1 from point E toward the first external portion 8, a point L1 from point E toward the first external portion 8 and a straight line perpendicular to the first external portion 8 at point E, and the outermost periphery of the second region 7. The first portion 10 may be a region surrounded by the first external portion 8, a straight line perpendicular to the first external portion 8 at a point L1 from point E toward the first external portion 8, and the outermost periphery of the second region 7. The first portion 10 is connected to the first external portion 8. The second portion 11 is connected to the second external portion 9. The second portion 11 includes a crack 12. If the crack 12 crosses or starts at the part connecting point E where the first external portion 8 and the second external portion 9 meet in the second external portion 9 or the first external portion 8 and a point L1 away from point E toward the first external portion 8, or if the starting point of the crack is within the second portion 11, the crack 12 may be considered to be included in the second portion 11.

[0018] The cracks 12 are formed, for example, from the periphery of the second outer shape portion 9 toward the outer periphery of the second region 7. In this case, the width of the cracks 12 increases as they move from the periphery of the second outer shape portion 9 toward the outer periphery of the second region 7.

[0019] FIG. 4 is a plan view of another functional layer 3 according to the first embodiment of the present disclosure.

[0020] In a plan view, the periphery of the first region 6 includes a first outer shape portion 8 and a second outer shape portion 9. The first outer shape portion 8 is not a corner portion. The second outer shape portion 9 is a corner portion. A corner portion may be interpreted as a portion with an extremely high curvature, and the corner portion may be considered to be the second outer shape portion 9, and the point where the first outer shape portion 8 and the second outer shape portion 9 meet may be considered to be point E.

[0021] The second region 7 has a first portion 10 and a second portion 11. The first portion 10 is connected to the first outer portion 8. The second portion 11 is connected to the second outer portion 9. The second portion 11 includes a crack 12 that starts at a vertex 13 of the second outer portion 9.

[0022] In the functional layer of a light-emitting element, stress may occur during the manufacturing process, causing cracks or gaps between the functional layer and the underlying layer due to the functional layer lifting. If these cracks or gaps occur in the light-emitting region, the light-emitting efficiency may deteriorate. In the light-emitting element 101, by generating cracks 12 in the second portion 11, the stress of the functional layer 3 (first region 6) in the light-emitting region 5 is alleviated, making it less likely that cracks will occur in the functional layer 3 (first region 6) and that the functional layer 3 (first region 6) will lift in the light-emitting region 5. Therefore, the light-emitting element 101 can suppress a decrease in light-emitting efficiency.

[0023] 5 is an explanatory diagram of the second external shape portion 9. FIG. 5 shows an example based on FIG. 2. In a plan view, the length L' of the line connecting points 54 and 55 on the outline of the first region 6 along the outline of the first region 6 is longer than the length L of the line connecting points 54 and 55 at the shortest distance, and the portion where length L' is not the same as length L no matter how points 54 and 55 are taken can be considered to be the second external shape portion 9. It can be said that the outline of the first region 6 being a straight line (L = L'), as in the case of the first external shape portion 8, is synonymous with a curvature of zero.

[0024] In the light emitting element 101, by forming the cracks 12 in advance in the second portion 11, it is possible to relieve the stress generated in the functional layer 3. As a result, in the light emitting element 101, it is possible to reduce the risk of cracks being formed in the first region 6.

[0025] The first portion 10 may not have cracks 12, but if cracks 12 are present in the first portion 10, the opening area of ​​the cracks 12 per unit area in the second portion 11 may be larger than the opening area of ​​the cracks 12 per unit area in the first portion 10 in a plan view. The larger the opening area (the larger the area of ​​the cracked portion), the more the internal stress of the film is alleviated. This makes it less likely that cracks will occur in the functional layer 3 (first region 6) in the light-emitting region 5, and makes it less likely that the functional layer 3 (first region 6) will lift in the light-emitting region 5.

[0026] FIG. 6 is a cross-sectional view taken along the line A-A in FIG. 2. FIG. 6 shows a first example 1003 of the cross-sectional view taken along the line A-A and a second example 1004 of the cross-sectional view taken along the line A-A. The member indicated by reference numeral 56 is a member located below the functional layer 3, viewed as a single member. The layer indicated by reference numeral 56 may be, for example, the hole transport layer 52. The layer above the layer indicated by reference numeral 56 is the functional layer 3. As in the first example 1003, a portion of the second region 11 may not be present at the bottom of the crack 12, or as in the second example 1004, a portion of the second region 11 may be present at the bottom of the crack 12.

[0027] Figure 7 is a cross-sectional view taken along line B-B in Figure 2. Figure 8 is an enlarged view of range C in Figure 2. The surface roughness of the wall surface 14 of the second portion 11 that defines the crack 12 included in the second portion 11 may be 10 nm or more in terms of arithmetic mean roughness Ra. Each of Figures 7 and 8 shows an example in which no part of the second portion 11 is present at the bottom of the crack 12, as in the first example 1003. However, as in the second example 1004, a part of the second portion 11 may be present at the bottom of the crack 12.

[0028] [Embodiment 2] Fig. 9 is a plan view of a functional layer 3 and a partition wall 17 according to embodiment 2 of the present disclosure. Fig. 10 is a plan view of another functional layer 3 and a partition wall 17 according to embodiment 2 of the present disclosure. Fig. 11 is a cross-sectional view taken along CC in Fig. 9. Fig. 12 is a cross-sectional view taken along DD in Fig. 9.

[0029] The light emitting element 101 may include a partition wall 17 located outside the first region 6 in a plan view. At least a part of the second region 7 may be located above the partition wall 17.

[0030] In plan view, the partition wall 17 may include a first edge 18 and a second edge 19. In FIG. 9 , the contour of the first edge 18 has a third curvature. The contour of the second edge 19 has a fourth curvature. The fourth curvature is greater than the third curvature. At least a part of the second portion 11 may be located above the second edge 19. The "edge" may be a surface including the vicinity of the edge in addition to the edge in a plan view along the contour. The contour of the edge may not be the contour of the outermost portion of the partition wall 17, but may be the contour of a portion corresponding to the end that defines the opening of the partition wall 17. The third curvature is greater than or equal to 0 / m and less than or equal to 1.5×10 ４ The fourth curvature may be less than 1.5×10 ３ / m or more and 3.1 × 10 ６ / m or less.

[0031] This allows the second outer portion 9, which has a large curvature, and the second edge portion 19, which also has a large curvature, to be positioned to correspond to each other in a plan view, thereby alleviating stress caused by thermal expansion of the partition wall 17. By having the positions of high curvature correspond to each other in the functional layer 3 and the partition wall 17, the direction of stress is aligned in the partition wall 17 and the functional layer 3, preventing the functional layer 3 from lifting.

[0032] 10 shows an example in which the partition wall 17 has a corner. The outer shape of the first edge portion 18 is not a corner. The outer shape of the second edge portion 19 is a corner. For example, at least a portion of the second region 11 shown in FIG. 4 (e.g., the second outer shape portion 9) may be located above the second edge portion 19. The first edge portion 18 and the second edge portion 19 may be distinguished in the same manner as the first outer shape portion 8 and the second outer shape portion 9.

[0033] This allows the second outer portion 9, which is a corner, and the second edge portion 19, which is also a corner, to be positioned to correspond to each other in a plan view, thereby alleviating stress caused by thermal expansion of the partition wall 17.

[0034] The partition 17 may include an unevenness 20 below the second portion 11. This significantly reduces the likelihood of cracks occurring in the functional layer 3 (first region 6) in the light-emitting region 5 and prevents the functional layer 3 (first region 6) from floating in the light-emitting region 5.

[0035] The thermal expansion coefficient of the partition wall 17 may be 20% or more of the thermal expansion coefficient of the functional layer 3. The thermal expansion coefficient of the partition wall 17 may be greater than the thermal expansion coefficient of the functional layer 3. The thickness of the partition wall 17 may be 50% or more of the thickness of the functional layer 3. The thickness of the partition wall 17 may be greater than the thickness of the functional layer 3. Each of these makes it easier for cracks 12 to occur in the second portion 11 of the functional layer 3, thereby alleviating the stress in the functional layer 3, thereby making it less likely for cracks to occur in the functional layer 3 (first region 6) in the light-emitting region 5 and making it less likely for the functional layer 3 (first region 6) to lift in the light-emitting region 5.

[0036] In a plan view, the shape of the first region 6 and the shape of the portion surrounded by the partition wall 17 may be similar. Furthermore, the shape of the portion surrounded by the partition wall 17 may be larger than the shape of the first region 6. This makes it possible to alleviate unexpected stress due to thermal expansion of the partition wall 17.

[0037] An underlayer may be formed between the functional layer 3 and the partition wall 17. The underlayer may be, for example, a charge transport layer such as a hole transport layer or a charge injection layer. Typically, the thickness of the partition wall 17 is several hundred nanometers to several micrometers, while the thickness of the underlayer is approximately 100 nm or less, so that the influence of thermal expansion of the underlayer can be ignored.

[0038] [Embodiment 3] FIG. 13 is a diagram illustrating a first example of a method for forming the functional layer 3. The method for forming the functional layer 3 may include steps S1 to S3. Step S1 is a step of applying a solution 58 in which a large number of quantum dots 16 modified with a ZnS precursor and a ZnS precursor 57 that is easily thermally decomposed are dispersed in a polar solvent. The member indicated by reference numeral 16c is the core of the quantum dot 16. The member indicated by reference numeral 16s is the shell of the quantum dot 16. Step S2 is a step of drying the solution 58 applied in step S1 to form a dried product 59. Step S3 is a step of irradiating the dried product 59 with ultraviolet light to expose the dried product 59. The product obtained by exposing the dried product 59 in step S3 is the functional layer 3. Instead of exposing the dried product 59, the dried product 59 may be baked.

[0039] 14 is a diagram illustrating a second example of a method for forming the functional layer 3. The method for forming the functional layer 3 may include steps S4 to S6. Step S4 is a step of modifying a large number of quantum dots 16 with halogen. Step S5 is a step of preparing a ZnS precursor solution 60 in which a large number of quantum dots 16 modified with halogen in step S4 are dispersed. Step S6 is a step of applying the ZnS precursor solution 60. The functional layer 3 is obtained by applying the ZnS precursor solution 60 in step S6.

[0040] 15 is a diagram illustrating a third example of a method for forming the functional layer 3. The method for forming the functional layer 3 may include steps S7 and S8. Step S7 is a step of mineralizing a large number of quantum dots 16. Step S8 is a step of applying a solution in which a large number of quantum dots 16 mineralized in step S7 are dispersed, followed by heating or light irradiation. In the third example of the method for forming the functional layer 3, the quantum dots 16 are coated with an Si—O network.

[0041] After forming a coating of a mixture of precursors of the inorganic matrix 4 and quantum dots 16 on a substrate, the precursors are reacted to form the inorganic matrix 4, thereby obtaining the functional layer 3.

[0042] When the functional layer 3 includes an inorganic matrix 4 derived from a metal complex, the inorganic matrix 4 is, for example, ZnS (zinc sulfide), ZnTeS, ZnMgS ２ , MgS, Ga ２ S ３ , ZnGa ２ S ４ , MgGa ２ S ４ The inorganic matrix 4 may be a sulfide semiconductor having a thickness of 1000 nm in a plane perpendicular to the film thickness direction at any position in the film thickness direction of the functional layer 3. ２ The functional layer 3 may have an area of ​​100 nm or more and 100 nm or less in average thickness, and the maximum thickness of the functional layer 3 may be two times or less than the minimum thickness.

[0043] Furthermore, when the functional layer 3 comprises an inorganic matrix 4 derived from, for example, silicon oxide, the inorganic matrix 4 is an oxide insulator.

[0044] The functional layer 3 may also include an inorganic matrix 4 other than a matrix derived from a metal complex or silicon oxide. Examples of the material for the inorganic matrix 4 include silicate minerals such as mica, and ceramics (inorganic sintered bodies). Examples of the ceramic include alumina (Al ２ O ３ ), zirconia, barium titanate (BaTiO ３ Oxide-based ceramics such as hydroxyapatite; hydroxide-based ceramics such as hydroxyapatite; carbonate-based ceramics; carbide-based ceramics such as silicon carbide (SiC); silicon nitride (Si ３ N ４ ) and other nitride ceramics; fluorite (CaF ２ ) and other halide-based ceramics; and phosphates.

[0045] The composition for the light-emitting layer used to form the light-emitting layer 15 as the functional layer 3 contains a ligand and may contain silicon oxide, and therefore the functional layer 3 may contain the ligand contained in the composition for the light-emitting layer or silicon oxide.

[0046] Examples of thermal expansion coefficients are given below: The thermal expansion coefficients of the following materials differ by approximately one order of magnitude from the thermal expansion coefficients of organic materials.

[0047] SiO ２ : 0.51 to 0.58 x 10 －６ / K (quartz glass) SiO ２ : 9 x 10 －６ / K (ordinary glass) ZnS: 6.5 x 10 －６ / °C (at 273K) PMMA: 60 x 10 －６ / °C Novolac-phenolic resin: 30-70 x 10 －６ The functional layer 3, which has a plurality of quantum dots 16 and an inorganic matrix 4 filling the spaces between the plurality of quantum dots 16, has a large difference in thermal expansion coefficient from the partition walls 17 and from the underlayer, and is therefore susceptible to the effects of thermal stress. The light-emitting element 101 can reduce the effects of the thermal stress, making it difficult for cracks to occur in the functional layer 3 (first region 6) in the light-emitting region 5 and difficult for the functional layer 3 (first region 6) to lift in the light-emitting region 5.

[0048] [Embodiment 4] Fig. 16 is a cross-sectional view showing a schematic configuration of a display device 201 according to embodiment 4 of the present disclosure. Fig. 16 particularly shows the layer configuration of each light-emitting element included in the display device 201, and omits some of the configuration between the light-emitting elements. The display device 201 includes three light-emitting elements 21R, 21G, and 21B that emit light of different colors. The light-emitting element 21R may emit red light, the light-emitting element 21G may emit green light, and the light-emitting element 21B may emit blue light.

[0049] Each of the three light-emitting elements 21R, 21G, and 21B is a light-emitting element 101. The functional layers 3 of the three light-emitting elements 21R, 21G, and 21B are spaced apart from each other.

[0050] According to the display device 201, the same effects as those of the light emitting device 101 can be obtained.

[0051] 17 is a flowchart showing an outline of a method for manufacturing a light-emitting element 101 according to a fifth embodiment of the present disclosure. The method for manufacturing the light-emitting element 101 includes steps Sa to Sc. Step Sa is a step of forming a lower electrode 1. Step Sb is a step of forming a functional layer 3 containing an inorganic matrix 4 above the lower electrode 1. Step Sc is a step of forming an upper electrode 2 above the functional layer 3.

[0052] The functional layer 3 formed in step Sb has the following configuration. In a plan view, it has a first region 6 located in the light-emitting region 5 of the light-emitting element 101, and a second region 7 located outside the first region 6 and connected to the first region 6. In a plan view, the periphery of the first region 6 includes a first outer shape portion 8 having a first curvature and a second outer shape portion 9 having a second curvature larger than the first curvature. The second region 7 has a first portion 10 connected to the first outer shape portion 8 and a second portion 11 connected to the second outer shape portion 9.

[0053] In the step Sb of forming the functional layer 3 , cracks 12 are further formed in the second portion 11 .

[0054] The configuration of the other functional layer 3 formed in step Sb is as follows. In plan view, it has a first region 6 located in the light-emitting region 5 of the light-emitting element 101, and a second region 7 located outside the first region 6 and connected to the first region 6. In plan view, the periphery of the first region 6 includes a first outer shape portion 8 that is not a corner, and a second outer shape portion 9 that is a corner. The second region 7 has a first portion 10 that is connected to the first outer shape portion 8, and a second portion 11 that is connected to the second outer shape portion 9.

[0055] In the step Sb of forming the functional layer 3, a crack 12 is further formed in the second portion 11, starting from the vertex 13 of the second outer shape portion 9.

[0056] According to the manufacturing method of the light emitting device 101, the light emitting device 101 capable of emitting high quality light can be manufactured with a high manufacturing yield.

[0057] 18 is a diagram showing a specific example of step Sb. Step Sb may include steps Sd to Sg. Step Sd is a step of forming a photoresist 22. Step Se is a step of applying a solution 61. The solution 61 can be said to be a material for forming the functional layer 3. Examples of the solution 61 include various solutions according to embodiment 3 of the present disclosure. Step Sf is a step of forming cracks 12 in the second portion 11. Step Sg is a step of removing the photoresist 22.

[0058] In the step Sb of forming the functional layer 3, at least the second portion 11 may be heated to form the cracks 12 in the second portion 11. This makes it possible to easily form the cracks 12.

[0059] In the step Sb of forming the functional layer 3, at least the second portion 11 may be heated and then cooled to form the cracks 12 in the second portion 11. This makes it possible to easily form the cracks 12.

[0060] In the step Sb of forming the functional layer 3, the thermal expansion coefficient is 80×10 －６ Alternatively, the functional layer 3 may be formed by lift-off using a photoresist 22 having a temperature of 1000 K / ° C. or higher. This allows the cracks 12 to be easily formed.

[0061] In step Sb of forming the functional layer 3, the functional layer 3 may be formed by lift-off using the photoresist 22, and at least the second portion 11 may be heated to a temperature equal to or higher than the melting point of the photoresist 22, thereby forming the cracks 12 in the second portion 11. This makes it possible to easily form the cracks 12.

[0062] Inorganic matrix 4 is SiO ２ If the step Sf includes the step S100, alcohol is formed before the end of the step Sf, and the cracks 12 may be formed in the step Sf due to stress relief that occurs when the alcohol slightly dissolves the photoresist 22.

[0063] In step Sb of forming the functional layer 3, the first region 6 may be formed inside the partition wall 17 in a plan view, and the shape of the first region 6 and the shape of the portion surrounded by the partition wall 17 may be formed similarly in a plan view. This makes it possible to alleviate unexpected stress due to thermal expansion of the partition wall 17.

[0064] In step Sb of forming the functional layer 3, the first region 6 may be formed inside the partition wall 17 in a planar view. In a planar view, the partition wall 17 may include a first edge portion 18 and a second edge portion 19, and the outer shape of the first edge portion 18 may have a third curvature, and the outer shape of the second edge portion 19 may have a fourth curvature greater than the third curvature. In step Sb of forming the functional layer 3, at least a portion of the second portion 11 may be formed above the second edge portion 19.

[0065] In step Sb of forming the functional layer 3, the first region 6 may be formed inside the partition wall 17 in a planar view. In a planar view, the partition wall 17 includes a first edge portion 18 and a second edge portion 19, and the outer shape of the first edge portion 18 may not be a corner, and the outer shape of the second edge portion 19 may be a corner. In step Sb of forming the functional layer 3, at least a part of the second portion 11 may be formed above the second edge portion 19.

[0066] The upper surfaces of the partition walls 17 may be formed unevenly. This makes it easy to form cracks 12 starting from the unevenness of the upper surfaces of the partition walls 17, and therefore the cracks 12 can be easily formed. One example of a technique for forming the upper surfaces of the partition walls 17 unevenly is to mix a black pigment or a scattering material into the material of the partition walls 17. In this case, the degree of unevenness of the upper surfaces of the partition walls 17 may be controlled by at least one of the size and the amount of the black pigment or scattering material added. Another possible technique is to expose the black pigment or scattering material by adjusting the exposure amount and slightly dissolving the surface of the photoresist 22 in the portions that are to be left.

[0067] Fig. 19 is a diagram illustrating the unevenness 71 on the upper surface of the partition wall 17. Fig. 20 is another diagram illustrating the unevenness 71 on the upper surface of the partition wall 17. In each of Fig. 19 and Fig. 20, only members and positions relevant to the explanation are shown, and other illustrations are omitted.

[0068] The width W12 of the crack 12 may be 5 μm to 10 μm, in which case the repetition interval P71 of the asperities 71 may be approximately the same as the width W12 (5 μm to 10 μm). The height H71 of the highest point of the asperities 71, based on the lowest point of the asperities 71, may be equal to or greater than the thickness of the functional layer 3 when the asperities 71 are ignored. If another layer is present between the functional layer 3 and the asperities 71, the height H71 may be equal to or greater than the sum of the thickness of the functional layer 3 and the thickness of the other layer when the asperities 71 are ignored. The height H71 may be equal to or greater than 100 nm and equal to or less than 1000 nm. The reason for including the other layer in the consideration is that if the asperities 71 are filled in by the other layer, it becomes difficult to form cracks 12.

[0069] 19, the convex shapes in the irregularities 71 preferably have pointed tips, but may also be substantially rectangular or have rounded tips. The multiple convex shapes included in the irregularities 71 may have different shapes, including different sizes and apex heights.

[0070] The irregularities 71 may be formed linearly along the direction in which cracks 12 are expected to form (line 62 in FIG. 20 ). Line 62 may extend in a direction perpendicular to the outer periphery of light-emitting region 5. Furthermore, for example, the convex shape of the irregularities 71 may extend radially outward from light-emitting region 5. This allows cracks 12 to be formed more efficiently.

[0071] The present disclosure is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment.

[0072] REFERENCE SIGNS LIST 1 Lower electrode 2 Upper electrode 3 Functional layer 4 Inorganic matrix 5 Light-emitting region of light-emitting element 6 First region 7 Second region 8 First outer shape portion 9 Second outer shape portion 10 First portion 11 Second portion 12 Crack 13 Vertex of second outer shape portion 14 Wall surface 15 Light-emitting layer 16 Quantum dot 17 Partition 18 First edge portion 19 Second edge portion 20 Concave and convex portions 21R, 21G, and 21B Light-emitting element 22 Photoresist 101 Light-emitting element 201 Display device

Claims

1. A light-emitting element comprising: a lower electrode and an upper electrode; and a functional layer containing an inorganic matrix, located above the lower electrode and below the upper electrode; wherein, in a planar view, the functional layer has a first region located in the light-emitting region and a second region located outside the first region and connected to the first region; wherein, in the planar view, the periphery of the first region includes a first outer shape portion having a first curvature and a second outer shape portion having a second curvature larger than the first curvature; and wherein the second region has a first portion connected to the first outer shape portion and a second portion connected to the second outer shape portion, and the second portion includes a crack.

2. A light-emitting element comprising: a lower electrode and an upper electrode; and a functional layer containing an inorganic matrix, located above the lower electrode and below the upper electrode, wherein, in a planar view, the functional layer has a first region located in the light-emitting region and a second region located outside the first region and connected to the first region, and in the planar view, the periphery of the first region includes a first outer shape portion that is not a corner and a second outer shape portion that is a corner, and the second region has a first portion connected to the first outer shape portion and a second portion connected to the second outer shape portion, and the second portion includes a crack, and the crack in the second portion includes a crack that originates from a vertex of the second outer shape portion.

3. A light-emitting element as described in claim 1 or 2, wherein the first portion also includes a crack, and in the planar view, the opening area of ​​the crack per unit area in the second portion is larger than the opening area of ​​the crack per unit area in the first portion.

4. The light-emitting element according to any one of claims 1 to 3, further comprising a partition wall located outside the first region in the planar view, and at least a portion of the second region is located above the partition wall.

5. The light-emitting element according to claim 4, wherein, in the plan view, the partition includes a first edge portion and a second edge portion, the outer shape of the first edge portion has a third curvature, and the outer shape of the second edge portion has a fourth curvature greater than the third curvature, and at least a portion of the second portion is located above the second edge portion.

6. The light-emitting element according to claim 4, wherein, in the plan view, the partition includes a first edge and a second edge, the outer shape of the first edge is not a corner, the outer shape of the second edge is a corner, and at least a portion of the second portion is located above the second edge.

7. The light-emitting device according to claim 5 or 6, wherein the partition wall includes an uneven surface below the second portion.

8. The light-emitting element according to claim 7, wherein the convex shapes of the irregularities extend radially outward from the light-emitting region.

9. The light-emitting device according to any one of claims 4 to 8, wherein the thermal expansion coefficient of the partition is greater than the thermal expansion coefficient of the functional layer.

10. The light-emitting device according to any one of claims 4 to 9, wherein the thickness of the partition wall is greater than the thickness of the functional layer.

11. A light-emitting element described in any one of claims 1 to 10, wherein the surface roughness of the wall surface of the second portion defining the crack contained in the second portion is 10 nm or more in terms of arithmetic mean roughness Ra.

12. The light-emitting element according to any one of claims 1 to 11, wherein the functional layer is a light-emitting layer.

13. The light-emitting element according to any one of claims 1 to 12, wherein the functional layer has a plurality of quantum dots, and the inorganic matrix fills spaces between the plurality of quantum dots.

14. The light-emitting element according to any one of claims 1 to 13, wherein the material of the inorganic matrix is ​​ZnS.

15. A display device comprising three light-emitting elements emitting light of different colors, each of the three light-emitting elements being a light-emitting element according to any one of claims 1 to 14, and the functional layers of the three light-emitting elements being spaced apart from one another.

16. A method for manufacturing a light-emitting element, comprising: a step of forming a functional layer; the functional layer comprises an inorganic matrix; and in a planar view, has: a first region located in a light-emitting region of the light-emitting element; and a second region located outside the first region and connected to the first region; in the planar view, the periphery of the first region has a first outer shape portion having a first curvature and a second outer shape portion having a second curvature larger than the first curvature; the second region has a first portion connected to the first outer shape portion and a second portion connected to the second outer shape portion; and the step of forming the functional layer further comprises forming cracks in the second portion.

17. A method for manufacturing a light-emitting element, comprising: a step of forming a functional layer; the functional layer comprises an inorganic matrix; and in a planar view, has: a first region located in a light-emitting region of the light-emitting element; and a second region located outside the first region and connected to the first region; in the planar view, the periphery of the first region includes a first outer shape portion that is not a corner and a second outer shape portion that is a corner; the second region has a first portion connected to the first outer shape portion and a second portion connected to the second outer shape portion; and the step of forming the functional layer further forms a crack in the second portion, starting from a vertex of the second outer shape portion.

18. The method for manufacturing a light-emitting element according to claim 16 or 17, wherein in the step of forming the functional layer, cracks are formed in the second portion by heating at least the second portion.

19. A method for manufacturing a light-emitting element according to any one of claims 16 to 18, wherein in the step of forming the functional layer, at least the second portion is heated and then cooled to form cracks in the second portion.

20. In the process of forming the functional layer, the thermal expansion coefficient is 80 x 10 －６ The method for manufacturing a light-emitting element according to claim 16 , wherein the functional layer is formed by lift-off using a photoresist having a temperature of 1000 K / ° C. or higher.

21. A method for manufacturing a light-emitting element described in any one of claims 16 to 20, wherein in the step of forming the functional layer, the functional layer is formed by lift-off using photoresist, and cracks are formed in the second portion by heating at least the second portion at a temperature equal to or higher than the melting point of the photoresist.

22. A method for manufacturing a light-emitting element described in any one of claims 16 to 21, wherein in the step of forming the functional layer, the first region is formed inside the partition wall in the planar view, and the shape of the first region and the shape of the portion surrounded by the partition wall are formed to be similar in the planar view.

23. A method for manufacturing a light-emitting element described in any one of claims 16 to 22, wherein in the step of forming the functional layer, the first region is formed inside the partition wall in the planar view, the partition wall includes a first edge portion and a second edge portion in the planar view, the outer shape of the first edge portion has a third curvature and the outer shape of the second edge portion has a fourth curvature greater than the third curvature, and in the step of forming the functional layer, at least a portion of the second portion is formed above the second edge portion.

24. A method for manufacturing a light-emitting element described in any one of claims 16 to 22, wherein in the step of forming the functional layer, the first region is formed inside the partition wall in the planar view, the partition wall includes a first edge portion and a second edge portion in the planar view, the outer shape of the first edge portion is not a corner and the outer shape of the second edge portion is a corner, and in the step of forming the functional layer, at least a portion of the second portion is formed above the second edge portion.

25. The method for manufacturing a light-emitting element according to any one of claims 22 to 24, wherein the upper surface of the partition wall is formed to have projections and recesses.

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