Manufacturing method of display device and display device

Abstract

This method for manufacturing a display device comprises: a step for applying a first quantum dot dispersion (L1), which contains a precursor (J) of a metal sulfide, a plurality of first quantum dots (Q1), and a solvent, to a first region (A1) and a second region (A2); a step for modifying the precursor (J) in the first region (A1) to a metal sulfide without modifying the precursor (J) in the second region (A2); and a step for removing the precursor (J) in the second region (A2) with a solvent (W).

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a display device and the display device. Background Art

[0002] In the light-emitting element disclosed in Patent Document 1, the light-emitting layer has a light-emitting region where an organic surfactant exists on the surface of quantum dots and emits light, and a non-light-emitting region where the organic surfactant does not exist on the surface of quantum dots and does not emit light. Prior art literature Patent Literature

[0003] Patent Document 1: WO2011 / 148791A1 (International Publication on December 1, 2011) Summary of the invention Technical Problems to be Solved by the Invention

[0004] The light-emitting element disclosed in Patent Document 1 has a problem of low durability because an organic surfactant is disposed on the surface of quantum dots in the light-emitting layer. Technical solutions for solving technical problems

[0005] A method for manufacturing a display device according to one embodiment of the present invention includes: a process of coating a first quantum dot dispersion on a first region and a second region, wherein the first quantum dot dispersion contains a metal sulfide precursor, a plurality of first quantum dots, and a solvent; a process of modifying the metal sulfide precursor in the first region into a metal sulfide without modifying the metal sulfide precursor in the second region; and a process of removing the metal sulfide precursor in the second region using a solvent.

[0006] A display device according to one aspect of the present invention includes: a first sub-pixel having a first light-emitting layer including a plurality of first light-emitting quantum dots and a metal sulfide; and a second sub-pixel having a non-light-emitting layer including non-light-emitting first quantum dots. Beneficial Effects

[0007] According to one aspect of the present disclosure, the durability of a display device can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a cross-sectional view showing a method for manufacturing the display device of this embodiment. Figure 2 It is a cross-sectional view showing a method for manufacturing the display device of this embodiment. Figure 3 This is a flowchart showing a method for manufacturing the display device according to this embodiment. Figure 4A : is a schematic diagram showing an example of the first quantum dot dispersion liquid. Figure 4B This is a cross-sectional view showing an example of a luminescent first quantum dot and a metal sulfide. Figure 4C This is a cross-sectional view showing an example of a non-luminescent first quantum dot. Figure 5 It is a plan view showing a configuration example of the display device of this embodiment. Figure 6 It is a cross-sectional view showing a configuration example of a display device according to this embodiment. Figure 7 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Figure 8 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig. 9 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.10 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.11 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.12 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.13 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.14 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.15 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.16 Yes means Figure 6 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.17 Yes means Figure 6 A schematic diagram of an example of the energy band structure of a quantum dot layer in a first sub-pixel of a display device shown. Fig.18 Yes means Figure 6 Schematic diagram of an example of the energy band structure of a quantum dot layer in a second sub-pixel of a display device shown. Fig.19 Yes means Figure 6 Schematic diagram of an example of the energy band structure of a quantum dot layer in a third sub-pixel of a display device shown. Fig. 20 It is a cross-sectional view showing another structure of the display device of this embodiment. Fig.21 It is a cross-sectional view showing another structure of the display device of this embodiment. Fig. 22 Yes means Fig.21 A cross-sectional view showing an example of a method for manufacturing a display device shown. Fig.23 It is a cross-sectional view showing another structure of the display device of this embodiment. Fig.24 It is a cross-sectional view showing another structure of the display device of this embodiment. Fig.25 It is a cross-sectional view showing another structure of the display device of this embodiment. Fig.26 It is a cross-sectional view showing another structure of the display device of this embodiment. DETAILED DESCRIPTION

[0009] [Implementation Method] Figure 1 It is a cross-sectional view showing a method for manufacturing the display device of this embodiment. Figure 2 It is a cross-sectional view showing a method for manufacturing the display device of this embodiment. Figure 3 FIG. 4 is a flowchart showing a method for manufacturing a display device according to the present embodiment. Figure 1 and Figure 3 As shown, the manufacturing method of the display device of this embodiment includes: a step (S10) of applying a first quantum dot dispersion liquid L1 including a metal sulfide precursor J, a plurality of first quantum dots Q1, and a solvent S to, for example, a first region A1 and a second region A2 of a base substrate KB; a step (S20) of modifying the metal sulfide precursor J in the first region A1 to metal sulfide M without modifying the metal sulfide precursor J in the second region A2; and a step (S30) of removing the metal sulfide precursor J in the second region A2 by using a solvent W. The base substrate KB may also include a pixel circuit substrate (TFT substrate).

[0010] In this way, by modifying the metal sulfide precursor J of the first quantum dot dispersion L1 on the first area A1 and removing the metal sulfide precursor J of the second area A2 by the solvent W, the durability of the light-emitting layer (quantum dot light-emitting layer) formed into a predetermined pattern can be improved. The metal sulfide precursor J of the first area A1 can also be modified by exposing the metal sulfide precursor J of the first area A1 and not exposing the metal sulfide precursor J of the second area A2. The modification of the metal sulfide precursor J refers to, for example, separating part or all of the non-metallic elements such as carbon, oxygen, hydrogen, and nitrogen of the precursor J by cutting off the molecular bond. Part of the separated carbon, oxygen, hydrogen, and nitrogen is removed as a gas to form a metal sulfide. The formed metal sulfides are in physical contact with each other, and a part of the metal sulfides can form atomic bonds with each other to form a continuous film. An inorganic matrix material (continuous film) containing a plurality of first quantum dots Q1 can also be formed by modifying the metal sulfide precursor J. In other words, the continuous film of the metal sulfide may be formed so as to fill the space between the first quantum dots Q1. For example, the continuous film has a thickness of 1000 nm in the direction along the plane parallel to the main surface of the base substrate KB. 2 The area above.

[0011] like Figure 1 As shown, the solvent S may be removed from the first quantum dot dispersion L1 of the first region A1 and the second region A2 before exposure. For example, the first quantum dot dispersion L1 of the first region A1 and the second region A2 may be heated at a temperature lower than the decomposition temperature of the metal sulfide precursor J to form a coating film F1. Exposure may also be performed using a mask (mask pattern) U1 disposed on the coating film F1. By exposure, a continuous film M1 of a metal sulfide containing two or more first quantum dots Q1 may be formed.

[0012] like Figure 1 As shown, after exposure, the metal sulfide M located on the first area A1 and the precursor J of the metal sulfide located in the second area A2 can also be exposed to a solvent to remove the precursor J of the metal sulfide in the second area A2. Thus, a first light-emitting layer E1 containing the luminescent first quantum dots Q1 can be formed on the first area A1, and an inactivated first non-luminescent layer N1 containing the non-luminescent first quantum dots P1 can be formed on the second area A2. At least a portion of the two or more first quantum dots Q1 located in the second area A2 can also be removed by a solvent W containing a surfactant. In the first non-luminescent layer N1, the non-luminescent first quantum dots P1 can also be agglomerated.

[0013] Figure 4A : is a schematic diagram showing an example of the first quantum dot dispersion liquid. Figure 4BFIG. 1 is a cross-sectional view showing an example of a first quantum dot Q1 and a metal sulfide M having luminescence properties. Figure 4C : is a cross-sectional view showing an example of a non-luminescent first quantum dot P1. The first quantum dot Q1 may also be a structure including a core 11 and a shell 12. The metal sulfide precursor J and the shell 12 may include the same metal element 10 (e.g., zinc element Zn). The metal sulfide precursor J may also be a complex including a metal element 10 and a sulfur element (S) (e.g., a metal complex of xanthogenic acid). The band gap of the metal sulfide M may be larger than the band gap of the first quantum dot Q1 (particularly the core 11).

[0014] The first quantum dot dispersion L1 may also contain halide ions H. The halide ions H may also be coordinated with the first quantum dots Q1 on the first region A1. The halide ions H on the second region A2 may also be removed by the solvent W.

[0015] The first quantum dot dispersion L1 may also contain an organic ligand agent Y. The organic ligand agent Y may be located on the surface of the first quantum dot Q1. The organic ligand agent Y may also be an anion (for example, a xanthate ion) that is bound to a cation of the metal element 10 contained in the shell 12. The organic ligand agent Y in the first area A1 may be modified into a metal sulfide by exposure. The organic ligand agent Y in the second area A2 may be removed by a solvent W. Thus, the first quantum dot Q1 may also be inactivated to become a non-luminescent first quantum dot P1. Surface defects 18 may also be formed on the non-luminescent first quantum dot P1 by removing the organic ligand agent Y. In the non-luminescent first quantum dot P1, the excitons generated by the recombination of electrons and holes are inactivated due to the surface defects 18.

[0016] like Figure 2 and Figure 3 As shown, the manufacturing method of the display device of the present embodiment may also include: a step (S40) of applying a second quantum dot dispersion liquid L2 including a metal sulfide precursor J, a plurality of second quantum dots Q2, and a solvent S to the third region A3 and the fourth region A4 of the first non-luminescent layer N1; a step (S50) of modifying the metal sulfide precursor J in the third region A3 to metal sulfide M without modifying the metal sulfide precursor J in the fourth region A4; and a step (S60) of removing the metal sulfide precursor J in the fourth region A4 by using a solvent W. The second quantum dot dispersion liquid L2 may be dried to form a coating film F2, and exposed using a mask (mask pattern) U2 disposed on the coating film F2 to form a continuous film M2 of metal sulfide containing two or more second quantum dots Q2.

[0017] Alternatively, the first quantum dot Q1 on the first area A1 has luminescence of a first color, and the second quantum dot Q2 on the third area A3 has luminescence of a second color. The wavelength region of light of the first color may also be located on a wavelength side shorter than the wavelength region of light of the second color. For example, the first color is blue, and the second color may also be green or red. The first area A1 and the third area A3 may also partially overlap when viewed from above. By partially overlapping the luminescent areas (A1, A3), the area of ​​only the non-luminescent layer generated between the luminescent areas disappears, and the area of ​​the luminescent area can be expanded.

[0018] The first and second quantum dot dispersions L1 and L2 may contain at least one selected from the group consisting of dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylformamide (NMF), formamide, N,N'-dimethylpropylene urea, dimethylacetamide, N-methylpyrrolidone, γ-butyrolactone, propylene carbonate, acetonitrile, 2-methoxyethanol, methyl acetate, ethyl acetate, ethyl formate, methyl formate, tetrahydrofuran, diethyl ether, tetrahydrothiophene, diethyl sulfide, chlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, and o-chlorotoluene as solvent S. Solvent S may also be a polar solvent.

[0019] The metal sulfide precursor J may also be a metal complex in which the metal element 10 is coordinated with xanthogenic acid, thiocarbamate, dithiocarbamate, thiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea, or thioacetamide. The metal element 10 is a zinc atom, and the metal sulfide M may also be zinc sulfide.

[0020] The display device 100 includes a first sub-pixel X1 having a first light-emitting layer E1 including a plurality of first light-emitting quantum dots Q1 and a metal sulfide M, and a second sub-pixel X2 having a first non-light-emitting layer N1 including first non-light-emitting quantum dots P1.

[0021] The first light-emitting layer E1 may include a continuous film M1 of a metal sulfide containing two or more first light-emitting quantum dots Q1. The continuous film M1 of the metal sulfide may be a continuous film of zinc sulfide (ZnS). The continuous film M1 of the metal sulfide may be a continuous film of zinc sulfide doped with magnesium. Compared with the first sub-pixel X1, the number of first quantum dots (including the light-emitting first quantum dots Q1 and the non-light-emitting first quantum dots P1) per unit area of ​​the second sub-pixel X2 may also be less.

[0022] The second subpixel X2 may include a second light-emitting layer E2 including a plurality of second light-emitting quantum dots Q2 and a metal sulfide M. The second light-emitting layer E2 may include a continuous film M2 of a metal sulfide including two or more second light-emitting quantum dots Q2.

[0023] The first sub-pixel X1 may also include a second non-luminescent layer N2 including a non-luminescent second quantum dot P2. In the first sub-pixel X1, the second non-luminescent layer N2 including the non-luminescent second quantum dot P2 may also be formed at a layer higher than the first luminescent layer E1. The second non-luminescent layer N2 including the non-luminescent second quantum dot P2 may be thinner than the first luminescent layer E1. In the second sub-pixel X2, the second luminescent layer E2 may also be formed at a layer higher than the first non-luminescent layer N1 including the non-luminescent first quantum dot P1.

[0024] The particle size of each of the two or more first luminescent quantum dots Q1 may be smaller than the particle size of the non-luminescent second quantum dots P2. The wavelength region of light emitted by each of the two or more first luminescent quantum dots Q1 may be located on the shorter wavelength side than the wavelength region of light emitted by each of the two or more second luminescent quantum dots Q2.

[0025] The display device 100 may include a third sub-pixel X3. The third sub-pixel X3 may include a third light-emitting layer E3 including a plurality of third light-emitting quantum dots Q3 and a continuous film M3 of a metal sulfide, a first non-light-emitting layer N1 including a first non-light-emitting quantum dot P1, and a second non-light-emitting layer N2 including a second non-light-emitting quantum dot P2. The third light-emitting layer E3 may be located on an upper layer of the second non-light-emitting layer N2.

[0026] The display device 100 may have an upper portion ZB (for example, including a charge functional layer and a common electrode) located above the third light-emitting layer E3, and the first subpixel X1 and the second subpixel X2 may each have a third non-luminescent layer N3 including non-luminescent third quantum dots P3.

[0027] [Example] Figure 5 It is a plan view showing a configuration example of the display device of this embodiment. Figure 5 The display device 100 shown in FIG. 1 includes: a display unit 15 including a first sub-pixel X1, a second sub-pixel X2, and a third sub-pixel X3; and a driving circuit 25 for driving the display unit 15. For example, the first sub-pixel X1 includes a first light-emitting layer E1 (see FIG. 1 ). Figure 2 )'s light-emitting element 3 and pixel circuit 5.

[0028] Figure 6 It is a cross-sectional view showing a configuration example of a display device according to this embodiment. Figure 5The display device 100 shown includes: a supporting substrate SB; a transistor layer TL formed on the supporting substrate SB; a light-emitting element layer formed on the transistor layer TL; and a thin film sealing layer TEF covering the light-emitting element layer. The supporting substrate SB may be a rigid substrate such as a glass substrate or a flexible substrate such as a resin film. The transistor layer TL includes circuit elements such as transistors and wiring. Light-emitting elements are formed in the light-emitting element layer.

[0029] The light emitting element layer at least includes a first electrode PE located on the transistor layer TL, an edge cover film BK covering the edge of the first electrode PE, a second electrode CE opposite to the first electrode PE, and a quantum dot layer DL located between the first electrode PE and the second electrode CE. The light emitting element layer may also include functional layers such as a hole transport layer HTL, an electron transport layer ETL, a hole injection layer, an electron injection layer, a hole blocking layer, and an electron blocking layer.

[0030] One of the first electrode PE and the second electrode CE is a pixel electrode, and the other is a common electrode opposite to the pixel electrode. One of the first electrode PE and the second electrode CE is an anode, and the other is a cathode. In addition, at least one is a transparent electrode. In the following, for the sake of simplicity of description, unless otherwise specified, an example in which the first electrode PE is a pixel electrode and an anode is described. The scope of this embodiment is not limited to this.

[0031] The quantum dot layer DL includes a first light-emitting layer E1 and a first non-light-emitting layer N1, and the first light-emitting layer E1 and the first non-light-emitting layer N1 are the same layer. The first light-emitting layer E1 includes a continuous film M1 of a metal sulfide and light-emitting first quantum dots Q1, and the first non-light-emitting layer N1 includes non-light-emitting first quantum dots P1. In this specification, "same layer" means that the film is formed by the same process.

[0032] The quantum dot layer DL is a layer above the first light-emitting layer E1 and the first non-light-emitting layer N1, and includes a second light-emitting layer E2 and a second non-light-emitting layer N2, and the second light-emitting layer E2 and the second non-light-emitting layer N2 are the same layer. The second light-emitting layer E2 includes a continuous film M2 of a metal sulfide and light-emitting second quantum dots Q2, and the second non-light-emitting layer N2 includes non-light-emitting second quantum dots P2. In this specification, the "upper layer" refers to a film formed by a post-process.

[0033] The quantum dot layer DL is a layer above the second light-emitting layer E2 and the second non-light-emitting layer N2, and includes a third light-emitting layer E3 and a third non-light-emitting layer N3, and the third light-emitting layer E3 and the third non-light-emitting layer N3 are the same layer. The third light-emitting layer E3 includes a continuous film M3 of a metal sulfide and a third light-emitting quantum dot Q3, and the third non-light-emitting layer N3 includes a third non-light-emitting quantum dot P3.

[0034] The continuous films M1, M2, and M3 are, for example, continuous films of zinc sulfide (ZnS) or continuous films of zinc sulfide (ZnS) doped with magnesium (Mg). The materials of the continuous films M1, M2, and M3 are different from each other or may be the same. The continuous film M1 contains two or more first luminescent quantum dots Q1. Similarly, the continuous film M2 contains two or more second luminescent quantum dots Q2, and the continuous film M3 contains two or more third luminescent quantum dots Q3.

[0035] The luminescent first quantum dot Q1 emits a first color through excitons. The non-luminescent first quantum dot P1 is formed by the deactivation of the luminescent first quantum dot Q1 and does not emit light. In addition, the non-luminescent first quantum dot P1 does not emit light, which also includes the case where the non-luminescent first quantum dot P1 emits very dark and weak light compared to the luminescent first quantum dot Q1. Similarly, the luminescent second quantum dot Q2 emits a second color through excitons, and the non-luminescent second quantum dot P2 is formed by the deactivation of the luminescent second quantum dot Q2 and does not emit light. In addition, the non-luminescent second quantum dot P2 does not emit light, which also includes the case where the non-luminescent second quantum dot P2 emits very dark and weak light compared to the luminescent second quantum dot Q2. In addition, the luminescent third quantum dot Q3 emits a third color through excitons, and the non-luminescent third quantum dot P3 is formed by the deactivation of the luminescent third quantum dot Q3 and does not emit light. In addition, the non-luminescent third quantum dot P3 does not emit light, which also includes the case where the non-luminescent third quantum dot P3 emits very dark and weak light compared to the luminescent third quantum dot Q3. Excitons are generated by the recombination of holes injected into the valence band and electrons injected into the conduction band in the first quantum dot Q1, the second quantum dot Q2, or the third quantum dot Q3.

[0036] The first sub-pixel X1 has a first light-emitting layer E1, a second non-light-emitting layer N2, and a third non-light-emitting layer N3. The first sub-pixel X1 also has: a first electrode PE located below the first light-emitting layer E1; a second electrode CE located above the first light-emitting layer E1; and an edge cover film BK covering the edge of the first electrode PE. When viewed from above, the entire region T1 of the first electrode PE that is not covered by the edge cover film BK overlaps with the first light-emitting layer E1. Thus, the first sub-pixel X1 presents a first color.

[0037] The second sub-pixel X2 includes a first non-luminous layer N1, a second luminous layer E2, and a third non-luminous layer N3, and further includes a first electrode PE located below the second luminous layer E2, a second electrode CE located above the second luminous layer E2, and an edge cover film BK covering the edge of the first electrode PE. When viewed from above, a region T2 of the first electrode PE that is not covered by the edge cover film BK overlaps the second luminous layer E2 as a whole. Thus, the second sub-pixel X2 presents a second color.

[0038] The third sub-pixel X3 includes a first non-luminescent layer N1, a second non-luminescent layer N2, and a third luminescent layer E3, and further includes a first electrode PE located below the third luminescent layer E3, a second electrode CE located above the third luminescent layer E3, and an edge cover film BK covering the edge of the first electrode PE. When viewed from above, a region T3 of the first electrode PE that is not covered by the edge cover film BK overlaps the third luminescent layer E3 as a whole. Thus, the third sub-pixel X3 presents a third color.

[0039] (Manufacturing method of display device) Figure 7 to Figure 16 Yes means Figure 6 A cross-sectional view of an example of a method for manufacturing a display device shown in FIG. Figure 7 As shown, first, a supporting substrate SB, a transistor layer TL and a first electrode PE, an edge cover film BK and a hole transport layer HTL are prepared. Then, a first quantum dot dispersion L1 is applied on the hole transport layer HTL. The upper surface of the hole transport layer HTL includes a first area A1 corresponding to the first sub-pixel X1 and a second area A2 corresponding to the second sub-pixel X2 and the third sub-pixel X3, and the first quantum dot dispersion L1 is applied on both the first area A1 and the second area A2. The first quantum dot dispersion L1 contains a metal sulfide precursor J1, a plurality of luminescent first quantum dots Q1, a ligand agent YH1 and a solvent S1.

[0040] The metal sulfide precursor J1 is a precursor of the continuous film M1, for example, a precursor of zinc sulfide. The precursor J1 is prepared using a metal source and a sulfur source. The metal source is, for example, at least one selected from the group consisting of metal acetates, metal nitrates, and metal halides. The sulfur source is, for example, at least one selected from the group consisting of xanthogenic acid, thiocarbamates, dithiocarbamates, thiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea, and thioacetamide. Alternatively or in addition, the precursor J1 may also contain a metal complex in which the sulfur source is coordinated to the metal element.

[0041] At least a portion of the ligand YH1 is coordinated to the first quantum dot Q1 in the first quantum dot dispersion L1. The ligand YH1 includes an organic ligand Y, a halide ion H, or both. The organic ligand Y can be a sulfur source of the precursor J. For example, xanthogenic acid functions as both the organic ligand Y and the sulfur source. The solvent S1 is a polar solvent.

[0042] like Figure 8As shown, then, the solvent S1 is removed from the first quantum dot dispersion L1 applied to the first area A1 and the second area A2 to obtain a coating film F1. Specifically, the first quantum dot dispersion L1 is heated at a temperature lower than the decomposition temperature of the precursor J1 or dried in a vacuum to remove the solvent S1. When the ligand agent YH1 includes an organic ligand agent Y, the heating temperature is preferably lower than the decomposition temperature of the organic ligand agent Y.

[0043] like Fig. 9 As shown, then, the precursor J1 of the first area A1 is modified into a metal sulfide without modifying the precursor J1 of the second area A2. For example, a mask U1 having an optical opening corresponding to the first sub-pixel X1 is used to irradiate the coating F1 with ultraviolet rays in a wavelength region where the precursor J1 shows absorption or infrared rays that can perform local heating. The precursor J1 of the first area A1 is exposed, and the precursor J1 of the second area is not exposed, thereby modifying the precursor J1 of the first area A1. The precursor J1 is decomposed by exposure to generate a metal sulfide. The metal sulfide forms a continuous film M1 containing two or more first quantum dots Q1. In the case where the ligand agent YH1 includes an organic ligand agent Y, the organic ligand agent Y of the first area A1 can be decomposed by the exposure to modify it into a metal sulfide. Carbon atoms, hydrogen atoms, nitrogen atoms, etc. can remain in the continuous film M1 even if they are oxidized and volatilized.

[0044] like Fig.10 As shown, then, the precursor J1 of the second area A2 is removed by the solvent W1. For example, after exposure, the continuous film M1 located on the first area A1 and the precursor J1 located on the second area are exposed to the solvent W1. The solvent W1 does not dissolve the continuous film M1. In the case where the ligand agent YH1 contains halide ions H, the halide ions H are still coordinated with the first quantum dots Q1 on the first area A1. The halide ions H or the organic ligand agent Y of the second area A2 are removed by the solvent W1, and the first quantum dots Q1 on the second area A2 are deactivated and become non-luminescent first quantum dots P1. Then, the solvent W1 is removed. The solvent W1 is, for example, an organic solvent.

[0045] As described above, a first light-emitting layer E1 is formed in a first area A1 corresponding to the first sub-pixel X1 from the coating F1, and a first non-light-emitting layer N1 is formed in a second area A2 corresponding to the second sub-pixel X2 and the third sub-pixel X3. The carbon atoms contained in the first light-emitting layer E1 are less than 5 atomic %. In the case where the ligand YH1 contains halide ions H, the halogen atoms contained in the first light-emitting layer E1 are more than 1 atomic %. Regarding the first quantum dot Q1, the average value of the concentration of halogen atoms within 1 nm from its outermost surface is higher than the average value of the concentration of halogen atoms at other positions that are more than 1 nm away from the outermost surfaces of the plurality of first quantum dots Q1. Here, "other positions" can also be said to be positions where the first quantum dot Q1 does not exist within 1 nm.

[0046] like Fig.11 As shown, then, the second quantum dot dispersion L2 is coated on the first light-emitting layer E1 and the first non-light-emitting layer N1. The upper surface of the first non-light-emitting layer N1 includes a third area A3 corresponding to the second sub-pixel X2, and a fourth area A4 corresponding to the third sub-pixel X3, and the second quantum dot dispersion L2 is coated on both the third area A3 and the fourth area A4. The second quantum dot dispersion L2 includes a metal sulfide precursor J2, a plurality of luminescent second quantum dots Q2, a ligand agent YH2, and a solvent S2. The precursor J2, the ligand agent YH2, and the solvent S2 in the second quantum dot dispersion L2 can be the same as or different from the precursor J1, the ligand agent YH1, and the solvent S1 in the above-mentioned first quantum dot dispersion L1.

[0047] By this coating, the second quantum dot Q2 is placed on the first quantum dot Q1, P1. In order to reduce the second quantum dot Q2 from invading the gap between the first quantum dot Q1, P1, it is preferred that the particle size of the first quantum dot Q1, P1 is smaller than the particle size of the second quantum dot Q2. Typically, there is a tendency that the smaller the particle size of the quantum dot is, the closer the wavelength region of the light emitted by the quantum dot is to the short wavelength side. Therefore, it is preferred that the wavelength region of the first color light emitted by the first quantum dot Q1 is closer to the short wavelength side than the wavelength region of the second color light emitted by the second quantum dot Q2.

[0048] like Fig.12 As shown, then, the solvent S2 is removed from the applied second quantum dot dispersion L2 to obtain a coating film F2. Next, the precursor J2 on the fourth area A4 and the first light-emitting layer E1 is not modified, but the precursor J2 on the third area A3 is modified into a metal sulfide. For example, a mask U2 having an optical opening corresponding to the second sub-pixel X2 is used to irradiate the coating film F2 with ultraviolet rays in a wavelength region where the precursor J2 shows absorption or infrared rays that can perform local heating. The precursor J2 on the third area A3 is decomposed by exposure to form a continuous film M2.

[0049] like Fig.13 As shown, then, the precursor J2 on the fourth area A4 and the first light-emitting layer E1 is removed by the solvent W2. For example, after exposure, the continuous film M2 located on the third area A3 and the precursor J2 located on the fourth area A4 and the first light-emitting layer E1 are exposed to the solvent W2. The solvent W2 does not dissolve the continuous film M2. The ligand agent YH on the fourth area A4 and the first light-emitting layer E1 is removed, and the second quantum dots Q2 on the fourth area A4 and the first light-emitting layer E1 are deactivated to become non-luminescent second quantum dots P2. Then, the solvent W2 is removed. The solvent W2 for removing the precursor J2 on the fourth area A4 may be the same as the solvent W1 for removing the precursor J1 on the second area A2, or it may be different.

[0050] As described above, the second light-emitting layer E2 and the second non-light-emitting layer N2 are formed by the coating film F2.

[0051] like Fig.14 As shown, then, the third quantum dot dispersion L3 is coated on the second light-emitting layer E2 and the second non-light-emitting layer N2. The upper surface of the second non-light-emitting layer N2 includes a fifth area A5 corresponding to the third sub-pixel X3 and a sixth area A6 corresponding to the first sub-pixel X1, and the third quantum dot dispersion L3 is coated on both the fifth area A5 and the sixth area A6. The third quantum dot dispersion L3 includes a metal sulfide precursor J3, a plurality of luminescent third quantum dots Q3, a ligand agent YH3, and a solvent S3. The precursor J3, the ligand agent YH3 and the solvent S3 in the third quantum dot dispersion L3 may be the same as or different from the precursor J1, J2, the ligand agent YH1, YH2 and the solvent S1, S2 in the above-mentioned first quantum dot dispersion L1 or the second quantum dot dispersion L2. The particle size of the second quantum dots Q2 and P2 is preferably smaller than the particle size of the third quantum dot Q3. It is preferable that the wavelength region of the second color light emitted by the second quantum dot Q2 is closer to the shorter wavelength side than the wavelength region of the third color light emitted by the third quantum dot Q3.

[0052] like Fig.15 As shown, then, the solvent S3 is removed from the coated third quantum dot dispersion L3 to obtain a coating film F3. Next, the precursor J3 on the sixth area A6 and the second light-emitting layer E2 is not modified, and the precursor J3 on the fifth area A5 is modified into a metal sulfide. For example, using a mask U3 having an optical opening corresponding to the third sub-pixel X3, the coating film F3 is irradiated with ultraviolet rays in a wavelength region where the precursor J3 shows absorption or infrared rays that can perform local heating. Through exposure, the precursor J3 in the fifth area A5 is decomposed to form a continuous film M3.

[0053] like Fig.16As shown, then, the precursor J3 on the sixth area A6 and the second light-emitting layer E2 is removed by the solvent W3. For example, after exposure, the continuous film M3 located on the fifth area A5 and the precursor J3 located on the sixth area A6 and the second light-emitting layer E2 are exposed to the solvent W3. The solvent W3 does not dissolve the continuous film M3. The ligand agent YH on the sixth area A6 and the second light-emitting layer E2 is removed, and the third quantum dots Q3 on the sixth area A6 and the second light-emitting layer E2 are inactivated to become non-luminescent third quantum dots P3. Then, the solvent W3 is removed. The solvent W3 for removing the precursor J3 on the sixth area A6 may be the same as or different from the solvents W1 and W2 for removing the precursors J1 and J2 on the second area A2 or the fourth area A4.

[0054] As described above, the third light-emitting layer E3 and the third non-light-emitting layer N3 are formed from the coating film F3. Next, the electron transport layer ETL, the second electrode CE and the thin film sealing layer TEF are formed to produce Figure 6 The display device 100 is shown.

[0055] (Belt structure of display device) Fig.17 Yes means Figure 6 FIG. 4 is a schematic diagram showing an example of a band structure of a quantum dot layer in a first sub-pixel X1 of a display device. Fig.18 Yes means Figure 6 Schematic diagram of an example of the band structure of the quantum dot layer in the second sub-pixel X2 of the display device shown. Fig.19 Yes means Figure 6 Schematic diagram of an example of a band structure of a quantum dot layer in a third sub-pixel X3 of a display device shown in FIG. Figure 17 to Figure 19 As shown, in this column, for the sake of simplicity, unless otherwise specified, the first quantum dot Q1, P1 is composed of a core 11 and a shell 12, the second quantum dot Q2, P2 is composed of a core 21 and a shell 22, the third quantum dot Q3, P3 is composed of a core 31 and a shell 32, and the shells 12, 22, 32 have the same band structure as the continuous films M1, M2, M3. However, the scope of the present embodiment is not limited to this.

[0056] When the electron affinity of the layer on the cathode side (i.e., the electron transport layer ETL side) is greater, the electron injection into the quantum dot layer DL is more effective. Typically, the closer the wavelength region of the light emitted by the quantum dot is to the short wavelength side, the smaller the electron affinity of the quantum dot tends to be. Therefore, when the first electrode PE is an anode, it is preferred that the wavelength region of the first color light emitted by the first quantum dot Q1 is on the shortest wavelength side, and the wavelength region of the third color light emitted by the third quantum dot Q3 is on the longest wavelength side.

[0057] In the first light-emitting layer E1, the continuous film M1 is buried between the first quantum dots Q1. On the other hand, in the first non-light-emitting layer N1, the first quantum dots P1 are not buried. In the second non-light-emitting layer N2, the second quantum dots P2 are not buried, and in the third non-light-emitting layer N3, the third quantum dots P3 are not buried. Therefore, the mobility of electrons in the first light-emitting layer E1 is smaller than the mobility of electrons in the first non-light-emitting layer N1, the second non-light-emitting layer N2, and the third non-light-emitting layer N3. The mobility of holes in the first light-emitting layer E1 is also small. In the second light-emitting layer E2, the continuous film M2 is buried between the second quantum dots Q2, and in the third light-emitting layer E3, the continuous film M3 is buried between the third quantum dots Q3. Therefore, the mobility of electrons and holes in the second light-emitting layer E2 and the third light-emitting layer E3 is also small.

[0058] (Effect) Compared with the prior art in which the light-emitting layer contains an organic ligand agent Y, the structure disclosed in the present invention has high durability and reliability.

[0059] According to the configuration of the present disclosure, no photoresist material is required in patterning the first light-emitting layer E1 , the second light-emitting layer E2 , and the third light-emitting layer E3 .

[0060] (Variation Example) Fig. 20 2 is a cross-sectional view showing another structure of the display device of the embodiment. Fig. 20 In the display device 100 shown, the first sub-pixel X1 has the first light-emitting layer E1, the second light-emitting layer E2 and the third light-emitting layer E3, and the second sub-pixel X2 has the first non-light-emitting layer N1, the second light-emitting layer E2 and the third light-emitting layer E3. Therefore, there is an advantage that the coating film F3 can be exposed without the mask U3.

[0061] Typically, between the first electrode PE and the second electrode CE, the mobility of electrons is greater than the mobility of holes. Therefore, the first sub-pixel X1 operates in an electron excess mode, and only the first light-emitting layer E1 located on the anode side of the multiple light-emitting layers of the first sub-pixel X1 substantially emits light. Similarly, among the multiple light-emitting layers of the second sub-pixel X2, only the second light-emitting layer E2 located on the anode side substantially emits light. Therefore, in the configuration of this variant, the first sub-pixel X1 also presents the first color, the second sub-pixel X2 presents the second color, and the third sub-pixel X3 presents the third color.

[0062] Fig.21 2 is a cross-sectional view showing other structures of the display device of this embodiment. Fig.21As shown, compared with the first light-emitting layer E1 of the first subpixel X1, the number of first quantum dots Q1 and P1 per unit area of ​​the first non-light-emitting layer N1 of the second subpixel X2 and the third subpixel X3 is smaller. The first non-light-emitting layer N1 is thinner than the second light-emitting layer E2 and the third light-emitting layer E3.

[0063] Similarly, the number of second quantum dots Q2 and P2 per unit area of ​​the second non-luminous layer N2 of the first sub-pixel X1 and the third sub-pixel X3 is smaller than that of the second luminous layer E2 of the second sub-pixel X2. The second non-luminous layer N2 is thinner than the first luminous layer E1 and the third luminous layer E3. In addition, the number of third quantum dots Q3 and P3 per unit area of ​​the third non-luminous layer N3 of the first sub-pixel X1 and the second sub-pixel X2 is smaller than that of the third luminous layer E3 of the third sub-pixel X3. The third non-luminous layer N3 is thinner than the first luminous layer E1 and the second luminous layer E2.

[0064] Fig. 22 Yes means Fig.21 A cross-sectional view of an example of a method for manufacturing a display device shown in FIG. Fig. 22 As shown, in the process of removing the precursor J1 of the second region A2, a solvent W4 containing a surfactant V1 is used. The solvent W4 removes at least a portion of the first quantum dots Q1 (or first quantum dots P1) on the second region A2. On the other hand, the continuous film M1 does not dissolve and protects the first quantum dots Q1 on the first region A1.

[0065] Similarly, using a solvent containing a surfactant, at least a portion of the second quantum dots Q2 (or second quantum dots P2) on the fourth region can be removed. In addition, using a solvent containing a surfactant, at least a portion of the third quantum dots Q3 (or third quantum dots P3) on the sixth region can be removed.

[0066] Fig.23 2 is a cross-sectional view showing other structures of the display device of this embodiment. Fig.23 As shown, all of the first quantum dots on the second region, all of the second quantum dots on the fourth region, and all of the third quantum dots on the sixth region may be removed. In this case, the display device 100 does not include the first non-luminescent layer, the second non-luminescent layer, and the third non-luminescent layer. Figure 21 to Figure 23 The example shown can be combined with the above Figure 6 to Figure 16 The example combination shown. A solvent not containing a surfactant may be used in any one or two of the steps of forming the first light-emitting layer E1 and the first non-light-emitting layer N1, the steps of forming the second light-emitting layer E2 and the second non-light-emitting layer N2, and the steps of forming the third light-emitting layer E3 and the third non-light-emitting layer N3, and a solvent containing a surfactant may be used in the remaining two or two.

[0067] Fig.24 It is a cross-sectional view showing another structure of the display device of this embodiment. Fig.24 The display device 100 shown includes a light source BL, a support substrate SB, a quantum dot layer DL formed on the support substrate SB, and a thin film sealing layer TEF covering the quantum dot layer DL. The wavelength range of the light emitted by the light source BL is located on the wavelength side shorter than any of the wavelength ranges of the light of the first color, the second color, and the third color. For example, when the first color, the second color, and the third color are blue, green, and red, the light source BL emits ultraviolet or purple light. The light source BL is, for example, a backlight, and the support substrate SB is a transparent substrate through which the light emitted by the light source BL can pass.

[0068] The excitons that make the luminescent first quantum dot Q1, the second quantum dot Q2, and the third quantum dot Q3 emit light are generated by the light emitted by the light source BL being absorbed by the first quantum dot Q1, the second quantum dot Q2, or the third quantum dot Q3. Therefore, the first light-emitting layer E1 functions as a wavelength conversion layer that absorbs light from the light source BL located below the first light-emitting layer E1 and radiates light of different wavelengths. The second light-emitting layer E2 and the third light-emitting layer E3 also function as wavelength conversion layers.

[0069] Fig.25 2 is a cross-sectional view showing another configuration of the display device of this embodiment. Fig.25 In the display device 100 shown, there may also be a sub-pixel X0 without a light-emitting layer. The sub-pixel X0 may also have a first non-light-emitting layer N1 and a second non-light-emitting layer N2. For example, when the display device 100 displays the three primary colors of red, green and blue, the light source BL emits blue light, the first quantum dot Q1 emits green light, and the second quantum dot Q2 emits red light.

[0070] Fig.26 2 is a cross-sectional view showing another modified example of the configuration of the display device according to the embodiment of the present disclosure. Fig.26 As shown, refer to Figure 21 to Figure 23 The example shown can be transformed into Fig.24 In addition, although the illustration is omitted, similarly, refer to Figure 21 to Figure 23 The example shown can be transformed Fig.25 Example shown.

[0071] The present invention is not limited to the above-mentioned embodiments, and various changes can be made within the scope of the claims. The embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. Moreover, by combining the technical means disclosed in each embodiment, new technical features can be formed. Description of Reference Numerals

[0072] Al: first area; A2: Second area; A3: The third area; A4: Area 4; BK: marginal cover membrane; BL: light source; CE: second electrode; Q1, P1: first quantum dot; Q2, P2: second quantum dot; Q3, P3: the third quantum dot; E1: first light-emitting layer; E2: second light-emitting layer; E3: the third luminescent layer; J, J1, J2, J3: precursors; L1: first quantum dot dispersion; L2: second quantum dot dispersion; L3: third quantum dot dispersion; M1, M2, M3: continuous membrane; N1: first non-luminescent layer; N2: second non-luminescent layer; N3: third non-luminescent layer; PE: first electrode; S, S1, S2, S3: solvent; V1: surfactant; W, W1, W2, W3, W4: solvent.

Claims

1. A method for manufacturing a display device, characterized in that: The manufacturing method comprises: A step of coating a first quantum dot dispersion on the first region and the second region, wherein the first quantum dot dispersion comprises a metal sulfide precursor, a plurality of first quantum dots, and a solvent; A step of modifying the precursor of the metal sulfide in the first region into the metal sulfide without modifying the precursor of the metal sulfide in the second region; and A step of removing the precursor of the metal sulfide in the second region by using a solvent.

2. The method for manufacturing a display device according to claim 1, wherein: The precursor of the metal sulfide in the first region is exposed to light, while the precursor of the metal sulfide in the second region is not exposed to light, so that the precursor of the metal sulfide in the first region is modified.

3. The method for manufacturing a display device according to claim 2, wherein: By the exposure, a continuous film of metal sulfide including two or more first quantum dots is formed on the first region.

4. The method for manufacturing a display device according to claim 2 or 3, characterized in that: Before the exposure, the solvent is removed from the first quantum dot dispersion in the first region and the second region.

5. The method for manufacturing a display device according to any one of claims 2 to 4, characterized in that: The first quantum dot dispersions in the first region and the second region are heated at a temperature lower than a decomposition temperature of the metal sulfide precursor.

6. The method for manufacturing a display device according to any one of claims 2 to 5, characterized in that: After the exposure, the precursors of the metal sulfide located on the first region and the metal sulfide located in the second region are exposed to the solvent.

7. The method for manufacturing a display device according to any one of claims 1 to 6, characterized in that: The first quantum dot dispersion contains halide ions.

8. The method for manufacturing a display device according to claim 7, wherein: The halide ions are coordinated to the first quantum dots on the first region.

9. The method for manufacturing a display device according to claim 7, wherein: The halide ions in the second region are removed by the solvent.

10. The method for manufacturing a display device according to any one of claims 1 to 6, characterized in that: The first quantum dot dispersion contains an organic ligand agent.

11. The method for manufacturing a display device according to claim 10, characterized in that: The organic ligand agent in the first region is modified into a metal sulfide by exposure.

12. The method for manufacturing a display device according to claim 10 or 11, characterized in that: The organic ligand agent of the second region is removed by the solvent.

13. The method for manufacturing a display device according to any one of claims 1 to 12, characterized in that: The solvent contains a surfactant, At least a portion of the two or more first quantum dots located in the second region is removed by the solvent.

14. The method for manufacturing a display device according to any one of claims 1 to 13, characterized in that: After the metal sulfide and the precursor of the metal sulfide are exposed to the solvent, a first light emitting layer containing first quantum dots is formed on the first region.

15. The method for manufacturing a display device according to any one of claims 1 to 14, characterized in that: After the metal sulfide and the precursor of the metal sulfide are exposed to the solvent, a non-luminescent layer including the first quantum dots deactivated on the second region is formed.

16. The method for manufacturing a display device according to claim 15, characterized in that: The non-emitting layer comprises a third region and a fourth region, The manufacturing method further comprises: A step of applying a second quantum dot dispersion liquid to the third region and the fourth region, wherein the second quantum dot dispersion liquid comprises a metal sulfide precursor, a plurality of second quantum dots, and a solvent; a step of modifying the precursor of the metal sulfide in the third region into the metal sulfide without modifying the precursor of the metal sulfide in the fourth region; and A step of removing the precursor of the metal sulfide in the fourth region by using a solvent.

17. The method for manufacturing a display device according to claim 16, wherein: The first quantum dots on the first region have luminescence of a first color, and the second quantum dots on the third region have luminescence of a second color.

18. The method for manufacturing a display device according to claim 17, characterized in that: The wavelength range of the light of the first color is on the shorter wavelength side than the wavelength range of the light of the second color.

19. The method for manufacturing a display device according to any one of claims 1 to 18, characterized in that: The precursor of the metal sulfide in the first quantum dot dispersion is prepared using at least one of metal acetate, metal nitrate and metal halide, and at least one of xanthogenic acid, thiocarbamate, dithiocarbamate, thiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea and thioacetamide.

20. The method for manufacturing a display device according to claim 19, wherein: The precursor of the metal sulfide in the first quantum dot dispersion includes a metal complex coordinated with a metal element by at least one of xanthogenic acid, thiocarbamate, dithiocarbamate, thiourea, N-methylthiourea, 1,3-dimethylthiourea, N,N'-dimethylthiourea, tetramethylthiourea, and thioacetamide.

21. The method for manufacturing a display device according to claim 1, wherein: The metal sulfide is zinc sulfide.

22. The method for manufacturing a display device according to claim 1, wherein: The solvent is a polar solvent.

23. A display device, characterized in that: include: A first sub-pixel having a first light-emitting layer, wherein the first light-emitting layer contains a plurality of first luminescent quantum dots and metal sulfide; The second sub-pixel has a non-luminescent layer, wherein the non-luminescent layer includes non-luminescent first quantum dots.

24. The display device according to claim 23, characterized in that The first light-emitting layer includes a continuous film of the metal sulfide including two or more first light-emitting quantum dots.

25. The display device according to claim 24, characterized in that: The continuous film of metal sulfide is a continuous film of zinc sulfide.

26. The display device according to claim 24, characterized in that The continuous film of metal sulfide is a continuous film of zinc sulfide doped with magnesium.

27. The display device according to any one of claims 23 to 26, characterized in that: Compared with the first sub-pixel, the number of the first quantum dots per unit area in the second sub-pixel is smaller.

28. The display device according to any one of claims 23 to 27, characterized in that: The second sub-pixel has a second light-emitting layer, and the second light-emitting layer contains a plurality of second light-emitting quantum dots and metal sulfide.

29. The display device according to claim 28, characterized in that The second light-emitting layer includes a continuous film of the metal sulfide including two or more second light-emitting quantum dots.

30. The display device according to claim 28 or 29, characterized in that: The first sub-pixel has a non-luminescent layer, and the non-luminescent layer includes non-luminescent second quantum dots.

31. The display device according to claim 30, characterized in that: In the first sub-pixel, a non-luminescent layer is formed on the first luminescent layer, and the non-luminescent layer includes non-luminescent second quantum dots.

32. The display device according to claim 30 or 31, characterized in that: The non-luminescent layer containing the second non-luminescent quantum dots is thinner than the first luminescent layer.

33. The display device according to any one of claims 28 to 32, characterized in that: In the second sub-pixel, the second light-emitting layer is formed above the non-light-emitting layer including the non-light-emitting first quantum dots.

34. The display device according to any one of claims 28 to 33, characterized in that: The particle size of each of the two or more first luminescent quantum dots is smaller than the particle size of the second non-luminescent quantum dots.

35. The display device according to any one of claims 28 to 34, characterized in that: The wavelength range of light emitted by each of the two or more first luminescent quantum dots is closer to the shorter wavelength side than the wavelength range of light emitted by each of the two or more second luminescent quantum dots.

36. The display device according to any one of claims 23 to 35, characterized in that: In the first light-emitting layer, carbon atoms account for 5 atomic % or less.

37. The display device according to any one of claims 23 to 36, characterized in that: The first light-emitting layer contains 1 atomic % or more of halogen atoms.

38. The display device according to any one of claims 23 to 37, characterized in that: The first light-emitting layer contains halogen atoms, and for each of the plurality of first quantum dots, an average concentration of halogen atoms within 1 nm from the outermost surface is more than 10% higher than an average concentration of halogen atoms at a position more than 1 nm away from the outermost surface of the plurality of first quantum dots.

39. The display device according to any one of claims 23 to 38, characterized in that: The display device comprises: A first electrode is located below the first light-emitting layer; and The second electrode is located above the first light-emitting layer.

40. The display device according to claim 39, characterized in that The display device includes an edge covering film that covers the edge of the first electrode. In a plan view, the entire region of the first electrode that is not covered by the edge cover film overlaps with the first light-emitting layer.

41. The display device according to any one of claims 23 to 38, characterized in that The display device comprises: a light source, which is located below the first light-emitting layer, The first light emitting layer functions as a wavelength conversion layer.

42. The display device according to any one of claims 23 to 41, characterized in that: A portion of the first light-emitting layer overlaps a portion of the second light-emitting layer in a plan view.

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