JP2022184258A - Manufacturing method of ion crystal pattern and light-emitting element - Google Patents

Abstract

To prevent an ion crystal layer from being exfoliated together with a sacrificial layer in patterning of the ion crystal layer using the sacrificial layer.SOLUTION: A manufacturing method of an ion crystal pattern includes steps of: forming a lower layer having a surface; forming an organic compound pattern containing an organic compound on a first region included in the surface; forming a precursor solution layer by coating the organic compound pattern and a second region included in the surface with a precursor solution containing a first solvent and a precursor of an ion crystal dispersed in the first solvent; forming an ion crystal layer comprising a first portion disposed in contact on the organic compound pattern and a second portion disposed in contact on the second region and containing the ion crystal by vaporizing the first solvent from the precursor solution layer; and removing the first portion by dissolving the organic compound pattern in a second solvent having a lower polarity than that of the first solvent.SELECTED DRAWING: Figure 4

Description

TECHNICAL FIELD The present disclosure relates to a method for manufacturing an ionic crystal pattern and a light emitting device.

The techniques described in Non-Patent Documents 1 and 2 relate to patterning of quantum dot layers using sacrificial layers.

In the technique described in Non-Patent Document 1, a polyvinylpyrrolidone (PVP) layer is formed on a substrate. A photoresist layer is then formed over the PVP layer. The photoresist layer is then exposed and developed to form a photoresist pattern. Subsequently, the PVP layer is etched by _O2 plasma through the photoresist pattern to form the PVP pattern. A quantum dot layer is then formed over the substrate overlying the photoresist pattern and the PVP pattern. The quantum dot layer comprises a first portion disposed over the photoresist pattern and the PVP pattern and a second portion not disposed over the photoresist pattern and the PVP pattern. The PVP pattern is then dissolved in alcohol to lift off the first portion of the quantum dot layer. This forms a quantum dot pattern.

In the technique described in Non-Patent Document 2, a fluoropolymer layer is formed on a substrate. Subsequently, a photoresist layer is formed on the fluoropolymer layer. The photoresist layer is then exposed and developed to form a photoresist pattern. Subsequently, the fluoropolymer layer is etched by _O2 plasma through the photoresist pattern to form a fluoropolymer pattern. Subsequently, a quantum dot layer is formed on the substrate overlying the photoresist pattern and the fluoropolymer pattern. The quantum dot layer comprises a first portion disposed over the photoresist pattern and the fluoropolymer pattern and a second portion not disposed over the photoresist pattern and the fluoropolymer pattern. Subsequently, the fluorine-based polymer pattern is dissolved in a fluorine-based stripping solution to lift off the first portion of the quantum dot layer. This forms a quantum dot pattern.

Wenhai Mei et al., "High-resolution, full-color quantum dot light-emitting diode display fabricated via photolithography approach", Nano Research, 2020, Vol. 13, p. 2485-2491 Chun Hao Lin et al., "Large-Area Lasing and Multicolor Perovskite Quantum Dot Patterns", Advanced Optical Materials, 2018, Vol. 6, 1800474

Patterning of a perovskite layer using a sacrificial layer has the problem that the perovskite layer dissolves in a solvent that dissolves the sacrificial layer, and the perovskite layer peels off together with the sacrificial layer. This problem also exists in the patterning of ion crystal layers other than perovskite layers.

The present disclosure has been made in view of this problem. An object of the present disclosure is to suppress separation of the ion crystal layer together with the sacrificial layer during patterning of the ion crystal layer using the sacrificial layer.

A method for producing an ionic crystal pattern according to one aspect of the present disclosure comprises: a) forming a lower layer having a surface; and b) forming an organic compound pattern containing an organic compound on a first region included in the surface. and c) applying a precursor solution containing a first solvent and an ionic crystal precursor dispersed in the first solvent onto the organic compound pattern and onto a second region included in the surface. d) volatilizing the first solvent from the precursor solution layer to form a first portion and the second portion disposed in contact with each other on the organic compound pattern; and e) a second solvent having a polarity lower than the polarity of the first solvent. and dissolving the organic compound pattern in to remove the first portion.

According to another aspect of the present disclosure, a method for producing an ionic crystal pattern includes: a) forming a lower layer having a surface; and b) forming an organic compound pattern containing an organic compound on a first region included in the surface. c) dimethylsulfoxide, N,N-dimethylformamide, N,N'-dimethylpropylene urea, dimethylacetamide, N- A precursor solution containing a first solvent containing at least one selected from the group consisting of methylpyrrolidone, gamma-butyrolactone, propylene carbonate and acetonitrile and an ionic crystal precursor dispersed in the first solvent is applied. d) volatilizing the first solvent from the precursor solution layer to form a first portion and the second portion disposed in contact with each other on the organic compound pattern; a second portion disposed over and in contact with the region; and e) hexane, octane, cyclohexane, toluene, xylene, chlorobenzene, ethyl acetate and butyl acetate. and dissolving the organic compound pattern in a second solvent containing at least one selected from the group consisting of to remove the first portion.

A light-emitting element according to another aspect of the present disclosure includes a substrate, a first electrode arranged on the substrate, a second electrode arranged on the substrate, the first electrode and the a light-emitting layer disposed between the second electrode and having an average thickness of 1.2 times or more of the average thickness of the central portion and containing ionic crystals.

According to the present disclosure, it is possible to suppress separation of the ion crystal layer together with the sacrificial layer in the patterning of the ion crystal layer using the sacrificial layer.

It is a top view which illustrates the display apparatus of 1st Embodiment typically. 3 is a cross-sectional view schematically illustrating each pixel provided in the display device of the first embodiment; FIG. 3 is a cross-sectional view schematically illustrating each light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a flow chart showing the flow of manufacturing the display device of the first embodiment. 4 is a flow chart showing the flow of forming each light-emitting layer provided in the display device of the first embodiment. FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; FIG. 4 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the first embodiment; 4 is a flow chart showing the flow of forming an ion crystal layer obtained during the formation of each light-emitting layer provided in the display device of the first embodiment. It is a sectional view showing each pixel with which the display of a 3rd embodiment is equipped typically. 10 is a flow chart showing the flow of forming each light-emitting layer provided in the display device of the third embodiment. FIG. 11 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the third embodiment; FIG. 10 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the third embodiment; FIG. 10 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; FIG. 10 is a diagram schematically illustrating a surface microstructure obtained during formation of a surface decorative layer provided in a display device according to a third embodiment; It is a sectional view showing each pixel with which the display of a 4th embodiment is equipped typically. 10 is a flow chart showing the flow of forming each light-emitting layer provided in the display device of the fourth embodiment. FIG. 11 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the fourth embodiment; FIG. 11 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the fourth embodiment; FIG. 11 is a cross-sectional view schematically illustrating an intermediate product obtained during the formation of a light-emitting layer provided in the display device of the fourth embodiment; 10 is a flow chart showing the flow of forming each charge-transporting material layer provided in the display device of the fourth embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or equivalent elements are denoted by the same reference numerals, and overlapping descriptions are omitted.

1. First Embodiment 1.1 Planar Structure of Display Device FIG. 1 is a plan view schematically illustrating a display device according to a first embodiment.

The display device 1 of the first embodiment illustrated in FIG. 1 comprises a plurality of pixels 11 .

A plurality of pixels 11 are arranged in a matrix. A plurality of pixels 11 may be arranged in a non-matrix pattern.

1.2 Cross-Sectional Structure of Pixel FIG. 2 is a cross-sectional view schematically illustrating each pixel provided in the display device of the first embodiment.

As illustrated in FIG. 2, each pixel 11 of the plurality of pixels 11 comprises light emitting elements 21R, 21G and 21B.

Each of the light emitting elements 21R, 21G and 21B constitutes a sub-pixel.

As illustrated in FIG. 2, each pixel 11 includes a substrate 31, a first electrode 32, a first charge transport layer 33, a light emitting layer 34R, a light emitting layer 34G, a light emitting layer 34B and a second charge transport layer 35. and a second electrode 36 .

The substrate 31 is one substrate arranged over the three light emitting elements 21R, 21G and 21B. The first electrode 32 may be a common electrode arranged across the three light emitting elements 21R, 21G and 21B, or may be a common electrode arranged over the three light emitting elements 21R, 21G and 21B. It may be a pixel electrode. The first charge transport layer 33 may be one charge transport layer arranged over the three light emitting elements 21R, 21G and 21B, or may There may be three charge transport layers arranged. The light emitting layers 34R, 34G and 34B are three light emitting layers respectively arranged in the three light emitting elements 21R, 21G and 21B. The second charge transport layer 35 may be one charge transport layer arranged over the three light emitting elements 21R, 21G and 21B, or may There may be three charge transport layers arranged. The second electrode 36 may be one common electrode arranged across the three light emitting elements 21R, 21G and 21B, or may be arranged in each of the three light emitting elements 21R, 21G and 21B. It may be three pixel electrodes.

A first electrode 32 , a first charge transport layer 33 , a light emitting layer 34 R, a light emitting layer 34 G, a light emitting layer 34 B, a second charge transport layer 35 and a second electrode 36 are disposed on the substrate 31 . A first charge transport layer 33 is disposed over the first electrode 32 . Emissive layers 34 R, 34 G and 34 B are disposed over first charge transport layer 33 . A second charge transport layer 35 is disposed over the light emitting layers 34R, 34G and 34B. A second electrode 36 is disposed over the second charge transport layer 35 . Thus, the light-emitting layers 34R, 34G and 34B are located between the first electrode 32 and the second electrode 36. FIG. Also, the first charge transport layer 33 is disposed between the first electrode 32 and the light emitting layers 34R, 34G and 34B. A second charge transport layer 35 is also disposed between the second electrode 36 and the light emitting layers 34R, 34G and 34B. Each pixel 11 may comprise a first charge injection layer disposed between a first electrode 32 and a first charge transport layer 33, a second electrode 36 and a second charge transport layer 35. and a second charge injection layer disposed between.

The main surface of each of the light emitting layers 34R, 34G, and 34B on the side opposite to the side on which the substrate 31 is located separates from the substrate 31 toward the edge. Therefore, the thickness of each of the light emitting layers 34R, 34G and 34B becomes thicker toward the edge. The average thickness of the edge portions of each light-emitting layer is 1.2 times or more the average thickness of the central portion of each light-emitting layer.

The average thickness of the edge of each light-emitting layer is determined by selecting two or more measurement points from the edge, measuring the thickness of each measurement point with a cross-sectional transmission electron microscope (cross-sectional TEM), and measuring two points. It is measured by averaging the thicknesses of the above measurement points to obtain an averaging value. This addition average value is the average thickness of the edge. The average thickness of the central portion of each light emitting layer is obtained by selecting two or more measurement points from the central portion, measuring the thickness of each measurement point with a cross-sectional TEM, and measuring the thickness of the two or more measurement points. are averaged to obtain an average value. This addition average value is the average thickness of the central portion.

In addition, the “end portion” of each light-emitting layer is a portion within 100 nm from the edge of each light-emitting layer in one cross section of the sub-pixel, and the “central portion” of each light-emitting layer is each light-emitting layer in the same cross section. and a portion within 50 nm (total width 100 nm) of the vicinity thereof.

1.3 Light Emission of Light Emitting Element The first electrode 32 is in contact with the light emitting layers 34R, 34G and 34B through the first charge transport layer 33. FIG. The first charge transport layer 33 transports a first charge. As a result, the first charge can be injected from the first electrode 32 through the first charge transport layer 33 into the light emitting layers 34R, 34G and 34B.

A second electrode 36 contacts the light emitting layers 34R, 34G and 34B through the second charge transport layer 35. FIG. A second charge transport layer 35 transports a second charge. As a result, the second charge can be injected from the second electrode 36 through the second charge transport layer 35 into the light emitting layers 34R, 34G and 34B.

When a potential difference is applied between the first electrode 32 and the second electrode 36, a first charge is generated from the first electrode 32 through the first charge transport layer 33 to the light emitting layers 34R, 34G and 34B. of charges are injected. Also, second charges are injected from the second electrode 36 through the second charge transport layer 35 into the light emitting layers 34R, 34G and 34B. As a result, the first charge and the second charge recombine in the light emitting layers 34R, 34G and 34B. This causes the light emitting layers 34R, 34G and 34B to emit light.

The light emitted by the light emitting layer 34R is, for example, red light. The light emitted by the light emitting layer 34G is, for example, green light. The light emitted by the light emitting layer 34B is, for example, blue light.

1.4 Inverted Structure and Conventional Structure The display device 1 has an inverted structure or a conventional structure.

When the display device 1 has an inverted structure, the first charges are electrons. Also, the second charge is a hole. Also, the first electrode 32 is a cathode. Also, the second electrode 36 is an anode. Also, the first charge transport layer 33 is an electron transport layer. Also, the second charge transport layer 35 is a hole transport layer.

If the display device 1 has a conventional structure, the first charges are holes. Also, the second charge is an electron. Also, the first electrode 32 is an anode. Also, the second electrode 36 is a cathode. Also, the first charge transport layer 33 is a hole transport layer. Also, the second charge transport layer 35 is an electron transport layer.

1.5 Materials Contained in Each Layer Each of the first electrode 32 and the second electrode 36 contains a conductive material. The conductive material includes, for example, at least one selected from the group consisting of metals and transparent conductive oxides. The metal includes, for example, at least one selected from the group consisting of Al, Cu, Au and Ag. The transparent conductive oxide is, for example, at least selected from the group consisting of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), aluminum zinc oxide (AZO) and boron zinc oxide (BZO). Includes 1 species. Each electrode of the first electrode 32 and the second electrode 36 may be one layer containing one conductive material, or two or more layers each containing two or more conductive materials different from each other. may be a laminate. Two or more layers may comprise both a layer of metal and a layer of transparent conductive oxide.

The electron-transporting layer contains an electron-transporting material. The electron-transporting material includes, for example, at least one selected from the group consisting of zinc oxide (ZnO), titanium oxide (TiO ₂ ) and strontium titanium oxide (SrTiO ₃ ). The electron-transporting material may be an electron-transporting material composed of one substance, or an electron-transporting material composed of a mixture of two or more substances.

The hole-transporting layer contains a hole-transporting material. The hole-transporting material includes, for example, at least one selected from the group consisting of hole-transporting inorganic materials and hole-transporting organic materials. The hole-transporting inorganic material includes, for example, at least one selected from the group consisting of metal oxides, nitrides and carbides. The metal includes at least one selected from the group consisting of Zn, Cr, Ni, Ti, Nb, Al, Si, Mg, Ta, Hf, Zr, Y, La, Sr and Mo. Hole-transporting organic materials include 4,4′,4″-tris(9-carbazoyl)triphenylamine (TCTA), 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino ]-biphenyl (NPB), zinc phthalocyanine (ZnPC), di[4-(N,N-ditolylamino)phenyl]cyclohexane (TAPC), 4,4′-bis(carbazol-9-yl)biphenyl (CBP), 2 ,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HATCN), poly(N-vinylcarbazole) (PVK), poly(2,7-( 9,9-di-n-octylfluorene)-(1,4-phenylene-((4-second-butylphenyl)imino)-1,4-phenylene (TFB), poly(triphenylamine) derivatives (Poly- TPD) and at least one selected from the group consisting of poly(3,4-ethylenedioxythiophene)/poly(4-styrenesulfonic acid) (PEDOT-PSS). or a mixture of two or more substances.

Each of the light emitting layers 34R, 34G and 34B contains a light emitting material. The luminescent material includes ionic crystals. Ionic crystals include, for example, metal halides and halide perovskite compounds. The perovskite compound includes, for example, at least one selected from the group consisting of a perovskite compound having a composition represented by the general formula _ABX3 and _a double perovskite compound having a composition represented by the general formula _A2CDX6 .

Among the ionic crystals, the perovskite compound is desirable as a compound used for each light-emitting layer because it has high conductivity. Furthermore, among perovskite compounds, halide perovskite compounds are desirable because a crystal thin film can be easily produced by a coating process using a polar solvent.

In perovskite compounds having a composition represented by the general formula ABX ₃ , A is desirably located at the body center of the unit cell. Also, the element B is desirably arranged at the face center of the unit cell. Also, the element X is desirably arranged at the vertices of the unit cell. A is an element or organic molecule that can be a monovalent cation, and includes, for example, at least one selected from the group consisting of Na, K, Rb, Cs, methylammonium and formamidinium. Further, element B is an element that can be a divalent cation, and is selected from the group consisting of, for example, Mg, Ca, Sr, Ba, Mn, Fe, Co, Ni, Cu, Zn, Ge, Sn, and lanthanoids. At least one type is included. Also, the element X contains at least one selected from the group consisting of F, Cl, Br and I. Perovskite compounds include, for example, CsZnF ₃ , CsZnCl ₃ , CsZnBr ₃ , CsZnI ₃ , RbZnF ₃ , RbZnCl ₃ , RbZnBr ₃ , RbZnI ₃ , CsZnF _x1 Cl _3-x1 , CsZnCl _x1 Br _3-x1 , Cx1 ZnIBr _{3 -x1 ZnIBr 3} , RbZnF _x1 Cl _3-x1 , RbZnCl _x1 Br _3-x1 and RbZnBr _x1 I _3-x1 . x1 satisfies 0<x1<3.

A double perovskite compound, like a perovskite compound, has high electrical conductivity, and is therefore desirable as a compound for use in each light-emitting layer. Furthermore, among the double perovskite compounds, the halide double perovskite compounds are desirable because a crystal thin film can be easily produced by a coating process using a polar solvent.

In a double perovskite compound having a composition represented by the general formula A ₂ CDX ₆ , A is desirably located at the body center of the unit cell. Also, the elements C and D are desirably arranged at the face center of the unit cell. Also, the element X is desirably arranged at the vertices of the unit cell. A is an element or organic molecule that can be a monovalent cation, and includes, for example, at least one selected from the group consisting of Na, K, Rb, Cs, methylammonium and formamidinium. Element C is an element that can be a monovalent cation, and includes, for example, at least one selected from the group consisting of Na, K, Cu, Ag, In and Tl. Element D is an element that can be a trivalent cation, such as Sc, Y, Al, Ga, In, Tl, Sb, Bi, La, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, It contains at least one selected from the group consisting of Ho, Er, Tm, Yb and Lu. Element X includes at least one selected from the group consisting of F, Cl, Br and I. Double perovskite compounds _include , for example _{, Cs2NaYCl6 , Cs2NaBiCl6 ,} Cs2NaInCl6 _{, Cs2NaCeCl6 , Cs2KYCl6 , Cs2KBiCl6 , Cs2KInCl6 ,} Cs2NaCeCl6 _{, Cs2Na x2K1 - x2YCl6 , Cs2NaYx2Ce1 - x2Cl6} and _{Cs2Znx2Na (1-x2) Bi (1-x2) Cl6} . X2 satisfies 0<x2<1.

FIG. 3 is a cross-sectional view schematically illustrating each light-emitting layer provided in the display device of the first embodiment.

As illustrated in FIG. 3, the luminescent material 41 contained in each of the luminescent layers 34R, 34G and 34B may include an ionic crystal 51 and a plurality of quantum dots 52. As shown in FIG.

When the light-emitting material 41 includes a plurality of quantum dots 52 , electrons and holes injected into each light-emitting layer of the light-emitting layers 34 R, 34 G and 34 B are injected into each quantum dot 52 . Also, electrons and holes recombine in each quantum dot 52 . This causes each quantum dot 52 to emit light. Thereby, the light emission efficiency of the light emitting layers 34R, 34G and 34B can be increased.

Each quantum dot 52 is dispersed in the ionic crystal 51 and covered with the ionic crystal 51 . Thereby, each quantum dot 52 can be stabilized.

A surface layer of each quantum dot 52 along the surface of each quantum dot 52 contains Zn. Thereby, at least one selected from the group consisting of F, Cl, Br and I contained in the ion crystal 51 can be easily coordinated to the surface layer of each quantum dot 52 .

Each quantum dot 52 comprises a core 61 , a shell 62 and a halogen anion 63 , as illustrated in FIG.

A shell 62 covers the surface of the core 61 .

Each quantum dot 52 is halogenated. Therefore, in each quantum dot 52 , halogen anions 63 are attached to the surface of the shell 62 . Thereby, the plurality of quantum dots 52 can be dispersed in the polar solvent together with the precursor of the ionic crystal 51 , and the plurality of quantum dots 52 can be dispersed in the ionic crystal 51 .

Each quantum dot 52 may be a quantum dot without shell 62 . When each quantum dot 52 is a quantum dot without shell 62 , halogen anions 63 are attached to the surface of core 61 .

The core 61 includes, for example, at least one selected from the group consisting of II-VI group compounds and III-V group compounds. Group II-VI compounds are, for example, MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe, ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe and HgTe At least one selected from the group consisting of The Group III-V compound includes, for example, at least one selected from the group consisting of GaAs, GaP, InN, InAs, InP and InSb.

The shell 62 contains, for example, at least one selected from the group consisting of ZnS, ZnSe, ZnSSe, ZnTe, Zn _2-x3 Si _x3 O ₂ . x3 satisfies 0<x3<1.

When the luminescent material 41 comprises the ionic crystal 51 and the plurality of quantum dots 52, the cation contained in the perovskite compound contained in the ionic crystal 51 is desirably Zn or a Lewis acid harder than Zn. This can suppress the occurrence of a chemical reaction at the interface between the surface of each quantum dot 52 and the ion crystal 51 . Lewis acids harder than Zn include, for example, Na, Mg, Al, K, Ca, Sc, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Rb, Sr, Y, In, Sn, Sb , Cs, Ba, Bi and La.

When the quantum dots are halogenated, a cation halide constituting the ionic crystal is dissolved in a polar solvent to prepare a solution.

Alternatively, the ligand-protected quantum dots are dispersed in a non-polar solvent to prepare a dispersion.

Subsequently, the prepared solution and dispersion are mixed with each other to prepare a mixed liquid, and the prepared mixed liquid is stirred.

Subsequently, the stirred mixed liquid is allowed to stand still to separate the mixed liquid into an upper layer liquid and a lower layer liquid. At this time, the ligand is released from the quantum dot. Also, the quantum dots migrate into the polar solvent and are halogenated in the polar solvent. Also, the ligand remains in the non-polar solvent. Therefore, the supernatant contains the ligand and the non-polar solvent. The underlayer liquid contains halogenated quantum dots, halides of the cations that make up the ionic crystals, and a polar solvent. The cation halides that make up the halogenated quantum dots and ionic crystals are dispersed in a polar solvent. Halides of cations forming the ionic crystal are precursors of the ionic crystal 51 .

The supernatant is then discarded. As a result, a solution containing halogenated quantum dots, halides of cations constituting ionic crystals, and a polar solvent is obtained.

1.6 Manufacturing Method of Display Device FIG. 4 is a flow chart showing the flow of manufacturing the display device according to the first embodiment.

When the display device 1 is manufactured, steps S101 to S106 shown in FIG. 4 are executed.

In step S101, the substrate 31 is prepared.

In subsequent step S102, the first electrode 32 is formed on the substrate 31. As shown in FIG.

In the subsequent step S103, the first charge transport layer 33 is formed on the first electrode 32. As shown in FIG.

In the following step S104, light emitting layers 34R, 34G and 34B are formed on the first charge transport layer 33. FIG.

In the subsequent step S105, the second charge transport layer 35 is formed on the light emitting layers 34R, 34G and 34B.

In the subsequent step S106, the second electrode 36 is formed on the second charge transport layer 35. FIG.

The light emitting layers 34R, 34G and 34B are formed by a lift-off method. When the first charge-transporting layer 33 is three charge-transporting layers arranged respectively in the three light-emitting elements 21R, 21G, and 21B, when the light-emitting layers 34R, 34G, and 34B are formed by the lift-off method, Three charge transport layers may be formed by a lift-off method. When the second charge-transporting layer 35 is three charge-transporting layers arranged respectively in the three light-emitting elements 21R, 21G, and 21B, when the light-emitting layers 34R, 34G, and 34B are formed by the lift-off method, Three charge transport layers may be formed by a lift-off method.

1.7 Formation of Light Emitting Layer FIG. 5 is a flow chart showing the flow of forming each light emitting layer provided in the display device of the first embodiment. FIGS. 6A to 6E, FIGS. 7A to 7E, and FIGS. 8A to 8E are cross-sectional views schematically illustrating intermediate products obtained in the course of forming a light-emitting layer provided in the display device of the first embodiment. It is a diagram.

When each of the light emitting layers 34R, 34G and 34B is formed, steps S111 to S116 shown in FIG. 5 are executed.

When the light-emitting layer 34R is formed, in step S111, an organic compound layer 72R illustrated in FIG. 6A is formed on the first charge transport layer 33, which is the lower layer. The organic compound layer 72R includes the first organic compound portion 72Ra disposed on the first region 33Ra included in the surface of the first charge transport layer 33 and the first region 33Ra included in the surface of the first charge transport layer 33. and a second organic compound portion 72Rb disposed over the second region 33Rb. The organic compound layer 72R contains an organic compound. The second region 33Rb is a region different from the first region 33Ra.

In the subsequent step S112, a photoresist layer 73R illustrated in FIG. 6A is formed on the organic compound layer 72R. The photoresist layer 73R contains photoresist.

In the subsequent step S113, the photoresist layer 73R is patterned. Thereby, a photoresist pattern 74R illustrated in FIG. 6B is formed. The photoresist pattern 74R is formed on the first organic compound portion 72Ra and not on the second organic compound portion 72Rb. When the photoresist layer 73R is patterned, the photoresist layer 73R is exposed and the exposed photoresist layer 73R is developed.

In subsequent step S114, the organic compound layer 72R is patterned. Thereby, an organic compound pattern 75R illustrated in FIG. 6C is formed. The organic compound pattern 75R is formed on the first region 33Ra and not on the second region 33Rb. The organic compound pattern 75R contains an organic compound. When the organic compound layer 72R is patterned, the photoresist pattern 74R is used as a mask to remove the second organic compound portion 72Rb by _O2 plasma etching. The organic compound pattern 75R is also called a sacrificial layer.

Through steps S111 to S114, an organic compound pattern 75R and a photoresist pattern 74R are formed on the first region 33Ra.

In the subsequent step S115, an ion crystal layer 76R illustrated in FIG. 6D is formed on the organic compound pattern 75R and the photoresist pattern 74R and on the second region 33Rb. The ion crystal layer 76R has a first portion 76Ra arranged in contact with the organic compound pattern 75R and the photoresist pattern 74R, and a second portion 76Rb arranged in contact with the second region 33Rb. Prepare. The ion crystal layer 76</b>R includes the ion crystals 51 . If the light-emitting layer 34R includes quantum dots 52, the ion crystal layer 76R includes quantum dots 52. FIG. Quantum dots 52 are dispersed in the ionic crystal 51 .

In subsequent step S116, the first portion 76Ra is lifted off and removed. As a result, a light-emitting layer 34R, which is an ion crystal pattern, is formed on the second region 33Rb, as illustrated in FIG. 6E. When the first portion 76Ra is lifted off, the organic compound pattern 75R is dissolved in the low polar solvent.

When the light-emitting layer 34G is formed, in step S111, an organic compound layer 72G illustrated in FIG. 7A is formed on the first charge transport layer 33, which is the lower layer. The organic compound layer 72G includes the first organic compound portion 72Ga disposed on the first region 33Ga included in the surface of the first charge transport layer 33 and the first region 33Ga included in the surface of the first charge transport layer 33. A second organic compound portion 72Gb is disposed over the second region 33Gb. The organic compound layer 72G contains an organic compound. The second region 33Gb is a region different from the first region 33Ga.

In the subsequent step S112, a photoresist layer 73G illustrated in FIG. 7A is formed on the organic compound layer 72G. The photoresist layer 73G contains photoresist.

In the subsequent step S113, the photoresist layer 73G is patterned. This forms a photoresist pattern 74G illustrated in FIG. 7B. A photoresist pattern 74G is formed on the first organic compound portion 72Ga and not on the second organic compound portion 72Gb. When the photoresist layer 73G is patterned, the photoresist layer 73G is exposed and the exposed photoresist layer 73G is developed.

In subsequent step S114, the organic compound layer 72G is patterned. Thereby, an organic compound pattern 75G illustrated in FIG. 7C is formed. The organic compound pattern 75G is formed on the first region 33Ga and not on the second region 33Gb. The organic compound pattern 75G contains an organic compound. When the organic compound layer 72G is patterned, the photoresist pattern 74G is used as a mask to remove the second organic compound portion 72Gb by _O2 plasma etching. The organic compound pattern 75G is also called a sacrificial layer.

Through steps S111 to S114, an organic compound pattern 75G and a photoresist pattern 74G are formed on the first region 33Ga.

In the subsequent step S115, an ion crystal layer 76G illustrated in FIG. 7D is formed on the organic compound pattern 75G and the photoresist pattern 74G and on the second region 33Gb. The ion crystal layer 76G has a first portion 76Ga arranged in contact with the organic compound pattern 75G and the photoresist pattern 74G and a second portion 76Gb arranged in contact with the second region 33Gb. Prepare. The ionic crystal layer 76G includes ionic crystals 51 . If the light-emitting layer 34G includes quantum dots 52, the ion crystal layer 76G includes quantum dots 52. FIG. Quantum dots 52 are dispersed in the ionic crystal 51 .

In subsequent step S116, the first portion 76Ga is lifted off and removed. As a result, a light-emitting layer 34G, which is an ion crystal pattern, is formed on the second region 33Gb, as shown in FIG. 7E. When the first portion 76Ga is lifted off, the organic compound pattern 75G is dissolved in the low polar solvent.

When the light emitting layer 34B is formed, the organic compound layer 72B illustrated in FIG. 8A is formed on the first charge transport layer 33, which is the lower layer, in step S111. The organic compound layer 72B includes the first organic compound portion 72Ba disposed on the first region 33Ba included in the surface of the first charge transport layer 33 and the first region 33Ba included in the surface of the first charge transport layer 33. and a second organic compound portion 72Bb disposed over the second region 33Bb. The organic compound layer 72B contains an organic compound. The second region 33Bb is a region different from the first region 33Ba.

In the subsequent step S112, a photoresist layer 73B illustrated in FIG. 8A is formed on the organic compound layer 72B. Photoresist layer 73B includes a photoresist.

In subsequent step S113, photoresist layer 73B is patterned. This forms a photoresist pattern 74B illustrated in FIG. 8B. The photoresist pattern 74B is formed on the first organic compound portion 72Ba and not on the second organic compound portion 72Bb. When the photoresist layer 73B is patterned, the photoresist layer 73B is exposed and the exposed photoresist layer 73B is developed.

In subsequent step S114, the organic compound layer 72B is patterned. Thereby, an organic compound pattern 75B illustrated in FIG. 8C is formed. The organic compound pattern 75B is formed on the first region 33Ba and not on the second region 33Bb. The organic compound pattern 75B contains an organic compound. When the organic compound layer 72B is patterned, the photoresist pattern 74B is used as a mask to remove the second organic compound portion 72Bb by _O2 plasma etching. The organic compound pattern 75B is also called a sacrificial layer.

Through steps S111 to S114, an organic compound pattern 75B and a photoresist pattern 74B are formed on the first region 33Ba.

In the subsequent step S115, an ion crystal layer 76B illustrated in FIG. 8D is formed on the organic compound pattern 75B and the photoresist pattern 74B and on the second region 33Bb. The ion crystal layer 76B has a first portion 76Ba arranged in contact with the organic compound pattern 75B and the photoresist pattern 74B, and a second portion 76Bb arranged in contact with the second region 33Bb. Prepare. The ionic crystal layer 76B includes the ionic crystals 51 . If light-emitting layer 34B includes quantum dots 52, ion crystal layer 76B includes quantum dots 52. FIG. Quantum dots 52 are dispersed in the ionic crystal.

In subsequent step S116, the first portion 76Ba is lifted off and removed. As a result, a light-emitting layer 34B, which is an ion crystal pattern, is formed on the second region 33Bb, as illustrated in FIG. 8E. When the first portion 76Ba is lifted off, the organic compound pattern 75B is dissolved in the low polar solvent.

1.8 Formation of Ion Crystal Layer FIG. 9 is a flow chart showing the flow of formation of an ion crystal layer obtained during formation of each light-emitting layer provided in the display device of the first embodiment.

When the ion crystal layers 76R, 76G and 76B are formed, steps S121 and S122 shown in FIG. 9 are performed.

When the ion crystal layer 76R is formed, a precursor solution layer is formed on the organic compound pattern 75R and the photoresist pattern 74R and on the second region 33Rb in step S121. When the precursor solution layer is formed, the precursor solution is applied over the organic compound pattern 75R and the photoresist pattern 74R and over the second region 33Rb. The precursor solution contains a polar solvent and precursors of the ionic crystals 51 . A precursor of the ionic crystal 51 is dispersed in a polar solvent. If the light-emitting layer 34R contains quantum dots 52, the precursor solution contains quantum dots 52. FIG. Quantum dots 52 are dispersed in a polar solvent. The end face of the portion formed on the second region 33Rb, which constitutes the precursor solution layer, contacts the organic compound pattern 75R and wets the organic compound pattern 75R. Therefore, the thickness of this portion increases as it approaches the end surface. This causes the main surface of each of the light-emitting layers 34R, 34G, and 34B on the side opposite to the side on which the substrate 31 is located to move away from the substrate 31 toward the edge.

In subsequent step S122, the polar solvent is volatilized from the precursor solution layer. Thereby, an ion crystal layer 76R is formed.

The ion crystal layer 76G is formed in the same manner as the ion crystal layer 76R, except that a precursor solution layer is formed over the organic compound pattern 75G and the photoresist pattern 74G and over the second region 33Gb. When the precursor solution layer is formed on the organic compound pattern 75G and the photoresist pattern 74G and on the second region 33Gb, the already formed light emitting layer 34R is covered with the organic compound pattern 75G. Therefore, the precursor solution does not dissolve the light emitting layer 34R. The ion crystal layer 76B is formed in the same manner as the ion crystal layer 76R, except that a precursor solution layer is formed over the organic compound pattern 75B and the photoresist pattern 74B and over the second region 33Bb. When the precursor solution layer is formed on the organic compound pattern 75B and the photoresist pattern 74B and on the second region 33Bb, the already formed light-emitting layers 34R and 34G are covered with the organic compound pattern 75B. Therefore, the precursor solution does not dissolve the light-emitting layers 34R and 34G.

1.9 Polarity of Solvent Although the precursor of the ionic crystal 51 dissolves in a polar solvent. Not soluble in low polar solvents. Therefore, in the precursor solution applied when forming the precursor solution layer, the precursor of the ion crystal 51 is dispersed in the polar solvent. Polar solvents are for example the group consisting of dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N'-dimethylpropyleneurea, dimethylacetamide, N-methylpyrrolidone, gamma-butyrolactone, propylene carbonate and acetonitrile. at least one selected from The ionic crystal layers 76R, 76G and 76B and the light emitting layers 34R, 34G and 34B are also soluble in polar solvents but not in low polar solvents.

Also, the precursor solution applied when the precursor solution layer is formed contacts the organic compound patterns 75R, 75G and 75B. Therefore, the organic compounds contained in the organic compound patterns 75R, 75G, and 75B, that is, the organic compounds contained in the organic compound layers 72R, 72G, and 72B are low-polarity organic compounds that do not dissolve in the polar solvent contained in the precursor solution. Low polar organic compounds include, for example, at least one selected from the group consisting of polyolefins, acrylic resins and silicone resins. Polyolefins include, for example, at least one selected from the group consisting of polyethylene, polyisoprene, polypropylene and polystyrene. The acrylic resin contains at least one selected from the group consisting of polymethyl methacrylate, polyethyl methacrylate and polybenzyl methacrylate. The silicone resin contains at least one selected from the group consisting of polydimethylsiloxane and polymethylphenylsiloxane.

The low-polarity organic compound dissolves in low-polarity solvents, but does not dissolve in polar solvents. Therefore, when the first portions 76Ra, 76Ga and 76Ba are lifted off, the organic compound patterns 75R, 75G and 75B are dissolved in the low polar solvent. A low polarity solvent has a polarity lower than that of the polar solvents described above. Low polarity solvents include, for example, at least one selected from the group consisting of hexane, octane, cyclohexane, toluene, xylene, chlorobenzene, ethyl acetate and butyl acetate. Since the ionic crystal 51 does not dissolve in the low-polarity solvent, the low-polarity solvent does not dissolve the second portions 76Rb, 76Gb and 76Bb.

The polarity of a solvent can be specified by the dielectric constant and dipole moment of the solvent.

According to the first embodiment, in patterning the ion crystal layers 76R, 76G and 76B using the organic compound patterns 75R, 75G and 75B serving as sacrificial layers, the ion crystal layers 76R, 76G and 76B are patterned together with the organic compound patterns 75R, 75G and 75B. can be suppressed from peeling off.

2. Second Embodiment In the following, points of difference of the second embodiment from the first embodiment will be described. As for the points that are not explained, the same configuration as that employed in the first embodiment is also employed in the second embodiment.

In the second embodiment, the first charge transport layer 33 directly contacting the light emitting layers 34R, 34G and 34B contains an inorganic compound.

The inorganic compound includes ZnO and preferably includes a dopant with which the ZnO is doped. The dopant desirably contains at least one selected from the group consisting of Al, Ag, In and Ga. The content of dopants in the total of ZnO and dopants is desirably 0.5% by weight or more and 5% by weight or less.

When the first charge transport layer 33 contains these inorganic compounds, the _O2 plasma etch removes the second organic compound portions 72Rb, 72Gb, and 72Bb followed by _O2 plasma in the second region. When brought into contact with 33Rb, 33Gb and 33Bb, the plasma treatment can reduce the contact angle of the second regions 33Rb, 33Gb and 33Bb with respect to the polar solvent contained in the precursor solution. Thereby, when the precursor solution is applied, the contact angle of the second regions 33Rb, 33Gb, and 33Bb with respect to the polar solvent contained in the precursor solution can be 40° or less. As a result, the grain size of the ion crystals contained in the light-emitting layers 34R, 34G and 34B can be reduced, the film thickness of the light-emitting layers 34R, 34G and 34B can be made uniform, and the light-emitting layers 34R, 34G and 34B can be made uniform. leakage can be suppressed.

The first charge transport layer 33 can be formed by a sol-gel method, a coating method, a sputtering method, an atomic layer deposition (ALD) method, or the like. When the first charge transport layer 33 is formed by the sol-gel method, a metal acetate solution is applied to form a coating layer, and the formed coating layer is heated at a temperature of 200° C. or higher and 400° C. or lower. When the first charge transport layer 33 is formed by a coating method, a solution in which nanoparticles are dispersed is applied. With these steps, the first charge transport layer 33 made of an oxide semiconductor can be formed.

The first charge transport layer 33 is formed before the second organic compound portions 72Rb, 72Gb and 72Bb are removed by _O2 plasma etching in step S114. However, since the first charge transport layer 33 is an inorganic compound layer that can withstand _O2 plasma etching, it can withstand _O2 plasma etching.

Even when the first charge transport layer 33 contains ZnO but does not contain a dopant of 0.5% by weight or more and 5% by weight or less, plasma treatment for a long time in an oxygen atmosphere can The contact angle of the surface of the first charge transport layer 33 can be reduced. However, when the first charge transport layer 33 contains ZnO and 0.5 wt % to 5 wt % dopant, the transparency of the first charge transport layer 33 is maintained while maintaining the first charge to the polar solvent. The contact angle on the surface of the transport layer 33 can be reduced. Also, the contact angle of the surface of the first charge transport layer 33 with respect to the polar solvent can be reduced by plasma treatment for a short period of time. Thereby, the time for performing O ₂ plasma etching can be shortened.

The method of reducing the contact angle adopted in the second embodiment has the advantage of being able to suppress an increase in the number of steps.

3 Third Embodiment In the following, points of difference between the third embodiment and the first embodiment will be described. For points that are not explained, the same configuration as that employed in the first embodiment is also employed in the third embodiment.

FIG. 10 is a cross-sectional view schematically illustrating each pixel included in the display device of the third embodiment.

As illustrated in FIG. 10, in the third embodiment, light emitting elements 21R, 21G and 21B are provided with surface decorative layers 37R, 37G and 37B, respectively.

The surface decorative layers 37R, 37G and 37B decorate the second regions 33Rb, 33Gb and 33Bb, respectively. Also, the surface decorative layers 37R, 37G and 37B are in direct contact with the light emitting layers 34R, 34G and 34B, respectively. First charge transport layer 33 includes an oxide. Therefore, hydroxyl groups and μ-oxo crosslinks are exposed on the surface of the first charge transport layer 33 . The oxide includes, for example, at least one selected from the group consisting of ZnO, ZnO doped with a dopant, NiO and TiO ₂ . Each of the surface decorative layers 37R, 37G and 37B contains at least one selected from the group consisting of amino groups, hydroxyl groups, carboxylic acids and ethylene glycol chains. At least one selected from the group consisting of an amino group, a hydroxyl group, a carboxylic acid and an ethylene glycol chain is directly or indirectly attached to the hydroxyl group and/or the μ-oxo bridge exposed on the surface of the first charge transport layer 33. Join. Thereby, surface decoration layers 37R, 37G and 37B, which are monomolecular films, are formed.

FIG. 11 is a flow chart showing the flow of forming a light-emitting layer provided in the display device of the third embodiment. 12, 13 and 14 are cross-sectional views schematically illustrating intermediate products obtained during the formation of the light-emitting layer provided in the display device of the third embodiment.

When each of the light emitting layers 34R, 34G and 34B is formed, steps S111 to S116 and S131 shown in FIG. 11 are executed.

When the light emitting layer 34R is formed, the surface decorative layer 37R illustrated in FIG. 12 is formed in step S131. The surface decorative layer 37R is formed by bringing a surface modifier into contact with the second region 33Rb. The surface modifier contains at least one selected from the group consisting of phosphonic acid, carboxylic acid and silane coupling agents. The surface decoration layer 37R is formed after the organic compound pattern 75R is formed in step S114. As a result, damage to the surface decorative layer 37R due to O ₂ plasma can be suppressed. The surface decoration layer 37R is formed before the ion crystal layer 76R is formed in step S115, that is, before the precursor solution layer is formed in step S121. In step S115, an ion crystal layer 76R is formed on the organic compound pattern 75R and the surface decorative layer 37R. Therefore, in step S121, the precursor solution is applied on the organic compound pattern 75R and the surface decorative layer 37R.

Light-emitting layer 34G is similar to light-emitting layer 34R, except that in step 131 a surface-modifying layer 37G, illustrated in FIG. formed in Light-emitting layer 34B is similar to light-emitting layer 34R, except that in step 131 a surface-modifying layer 37B, illustrated in FIG. formed in

15A to 15F are diagrams schematically illustrating surface microstructures obtained during the formation of the surface decorative layer provided in the display device of the third embodiment.

The surface microstructure illustrated in Figures 15A to 15F is for the case where the oxide contained in the first charge transport layer 33 comprises _TiO2 and the surface modifier comprises phosphonic acid.

When the surface decorative layers 37R, 37G and 37B are formed, the second regions 33Rb, 33Gb and 33Bb are brought into contact with phosphonic acid 81 as shown in FIG. 15A.

Subsequently, the first hydroxyl group 82 of the phosphonic acid 81 is deprotonated to form an O ^{2 -} group 83, as illustrated in FIGS. 15A and 15B. Protons 84 released by deprotonation are added to hydroxyl groups 85 exposed in the second regions 33Rb, 33Gb and 33Bb. This protonates the hydroxyl groups 85 to form H ₂ ⁺ O groups 86 .

15B and 15C, H ₂ ⁺ O groups 86 are dehydrated and Ti atoms 87 that were bound to H ₂ ⁺ O groups 86 are bound to O 2 ⁻ groups 83 .

Subsequently, the second hydroxyl group 88 of the phosphonic acid 81 is deprotonated to form an O ^{2 -} group 89, as illustrated in Figures 15C and 15D. Protons 90 released by deprotonation are added to μ-oxo bridges 91 exposed in the second regions 33Rb, 33Gb and 33Bb. This protonates the μ-oxo bridge 91 to form an OH ⁺ bridge 92 .

15D and 15E, the bond between the oxygen atom 93 and the Ti atom 87 that make up the OH ⁺ bridge 92 is cleaved to regenerate the hydroxyl group 94 . Ti atoms 87 are also bonded to O ^{2 -groups} 89 .

By repeating these reactions, a high-density phosphonic acid self-assembled membrane (SAM) 101 is formed on the second regions 33Rb, 33Gb and 33Bb, as illustrated in FIG. 13F. A high density phosphonic acid SAM film 101 is used as the surface decoration layers 37R, 37G and 37B.

The high-density phosphonic acid SAM film 101 is formed by these reactions, for example, by immersing the plasma-treated substrate in a tetrahydrofuran (THF) solution of phosphonic acid having a concentration of 0.1 mmol/l and then removing the THF solution. Then, the substrate is dried at a temperature of 120° C. for 48 hours, and the dried substrate is subjected to ultrasonic cleaning in methanol.

FIG. 16 is a diagram schematically illustrating a surface microstructure obtained during the formation of the surface decorative layer provided in the display device of the third embodiment.

The surface microstructure illustrated in FIG. 16 is intermediate when the oxide contained in the first charge transport layer 33 comprises TiO ₂ and the surface modifier comprises a silane coupling agent.

The silane coupling agent reacts with hydroxyl groups exposed in the second regions 33Rb, 33Gb and 33Bb. As a result, a low-density silane SAM film 102 is formed on the second regions 33Rb, 33Gb and 33Bb, as shown in FIG. The low density silane SAM film 102 is used as surface decoration layers 37R, 37G and 37B.

The surfaces of the surface decorative layers 37R, 37G and 37B have a contact angle of 40° or less with respect to the polar solvent contained in the precursor solution when the precursor solution is applied. As a result, the grain size of the ion crystals contained in the light-emitting layers 34R, 34G and 34B can be reduced, the film thickness of the light-emitting layers 34R, 34G and 34B can be made uniform, and the light-emitting layers 34R, 34G and 34B can be made uniform. leakage can be suppressed.

The method of reducing the contact angle adopted in the third embodiment can be adopted because the organic compound patterns 75R, 75G and 75B do not dissolve in the polar solvent.

4 Fourth Embodiment In the following, points of difference between the fourth embodiment and the first embodiment will be described. As for the points that are not explained, the same configuration as that employed in the first embodiment is also employed in the fourth embodiment.

FIG. 17 is a cross-sectional view schematically illustrating each pixel provided in the display device of the fourth embodiment.

As illustrated in FIG. 17, in the fourth embodiment, light emitting devices 21R, 21G and 21B are provided with other first charge transport layers 38R, 38G and 38B, respectively.

Another first charge transport layer 38R is disposed between the first charge transport layer 33 and the light emitting layer 34R. Another first charge transport layer 38G is disposed between the first charge transport layer 33 and the light emitting layer 34G. Another first charge transport layer 38B is disposed between the first charge transport layer 33 and the light emitting layer 34B. Other first charge transport layers 38R, 38G and 38B directly contact light emitting layers 34R, 34G and 34B, respectively. Other first charge transport layers 38 R, 38 G and 38 B contain charge transport materials different from the charge transport material contained in first charge transport layer 33 . Charge-transporting materials contained in other first charge-transporting layers 38R, 38G, and 38B are, for example, poly(3,4-ethylenedioxythiophene)/polystyrene sulfonic acid (PEDOT-PSS), polyethyleneimine (PEI). and at least one selected from the group consisting of ethoxylated polyethyleneimine (PEIE), and nanoparticles containing at least one selected from the group consisting of ZnO, ZnMgO, AlZnO and NiO.

FIG. 18 is a flow chart showing the flow of forming each light-emitting layer provided in the display device of the fourth embodiment. 19, 20, and 21 are cross-sectional views schematically illustrating intermediate products obtained during the formation of the light-emitting layer provided in the display device of the fourth embodiment.

When each of the light emitting layers 34R, 34G and 34B is formed, steps S111 to S116 and S141 shown in FIG. 10 are executed.

When the light-emitting layer 34R is formed, the charge-transporting material layer 78R illustrated in FIG. 19 is formed in step S141. The charge-transporting material layer 78R contains a charge-transporting material. The charge-transporting material layer 78R is formed after the organic compound pattern 75R is formed in step S114. As a result, damage to the other charge-transporting material layer 78R due to O ₂ plasma can be suppressed. The charge-transporting material layer 78R is formed before the ion crystal layer 76R is formed in step S115, that is, before the precursor solution layer is formed in step S121. In step S115, a precursor solution is applied onto the charge-transporting material layer 78R. In step S116, the first portion 78Ra of the charge-transporting material layer 78R and the first portion 76Ra of the ion crystal layer 76R are lifted off and removed. As a result, the second portion 78Rb of the charge-transporting material layer 78R and the second portion 76Rb of the ion crystal layer 76R form the other charge-transporting layer 38R and the light-emitting layer 34R, respectively.

When the light-emitting layer 34G is formed, in step S141, the charge-transporting material layer 78G illustrated in FIG. 20 is formed. The charge-transporting material layer 78G contains a charge-transporting material. The charge-transporting material layer 78G is formed after the organic compound pattern 75G is formed in step S114. As a result, damage to the other charge-transporting material layer 78G due to O ₂ plasma can be suppressed. The charge-transporting material layer 78G is formed before the ion crystal layer 76G is formed in step S115, that is, before the precursor solution layer is formed in step S121. In step S115, a precursor solution is applied onto the charge-transporting material layer 78G. In step S116, the first portion 78Ga of the charge-transporting material layer 78G and the first portion 76Ga of the ion crystal layer 76G are lifted off and removed. Thus, another charge transport layer 38G and a light emitting layer 34G are formed.

If the light-emitting layer 34B is formed, then in step S141, the charge-transporting material layer 78B illustrated in FIG. 21 is formed. The charge-transporting material layer 78B contains a charge-transporting material. The charge-transporting material layer 78B is formed after the organic compound pattern 75B is formed in step S114. As a result, damage to the other charge-transporting material layer 78B due to O ₂ plasma can be suppressed. The charge-transporting material layer 78B is formed before the ion crystal layer 76B is formed in step S115, that is, before the precursor solution layer is formed in step S121. In step S115, a precursor solution is applied onto the charge-transporting material layer 78B. In step S116, the first portion 78Ba of the charge-transporting material layer 78B and the first portion 76Ba of the ion crystal layer 76B are lifted off and removed. Thus, another charge transport layer 38B and a light emitting layer 34B are formed.

FIG. 22 is a flow chart showing the flow of forming the charge-transporting material layer provided in the display device of the fourth embodiment.

When the charge-transporting material layers 78R, 78G and 78B are formed, steps S151 and S152 shown in FIG. 22 are performed.

When the charge-transporting material layer 78R is formed, in step S151, a charge-transporting material solution layer is formed on the organic compound pattern 75R and the photoresist pattern 74R and on the second region 33Rb. When the charge-transporting material solution layer is formed, the charge-transporting material solution is applied over the organic compound pattern 75R and the photoresist pattern 74R and over the second region 33Rb. The charge-transporting material solution contains a polar solvent and a charge-transporting material. The charge-transporting material is dispersed in a polar solvent and has charge-transporting properties.

In subsequent step S152, the polar solvent is volatilized from the charge-transporting material solution layer. Thus, a charge transport material layer 78R is formed.

The charge-transporting material layer 78G is similar to the charge-transporting material layer 78R except that a charge-transporting material solution layer is formed on the organic compound pattern 75G and the photoresist pattern 74G and on the second region 33Gb. similarly formed. The charge-transporting material layer 78B is similar to the charge-transporting material layer 78R except that a charge-transporting material solution layer is formed on the organic compound pattern 75B and the photoresist pattern 74B and on the second region 33Bb. similarly formed.

The charge-transporting material solution applied when the charge-transporting material layers 78R, 78G and 78B are formed contacts the organic compound patterns 75R, 75G and 75B. Also, the organic compounds contained in the organic compound patterns 75R, 75G and 75B, that is, the organic compounds contained in the organic compound layers 72R, 72G and 72B are low-polarity organic compounds. Therefore, in the charge-transporting material solution, the charge-transporting material is dissolved in a polar solvent that does not dissolve the low-polarity organic compound. The polar solvent has a polarity higher than that of the low polarity solvent that dissolves the organic compound patterns 75R, 75G and 75B in lifting off the first portions 78Ra, 78Ga and 78Ba and the first portions 76Ra, 76Ga and 76Ba. Polar solvents are, for example, water, methanol, acetone, acetonitrile, dimethylsulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N'-dimethylpropyleneurea, dimethylacetamide, N-methylpyrrolidone, gamma-butyrolactone , at least one selected from the group consisting of propylene carbonate and acetonitrile.

The surfaces of the charge-transporting material layers 78R, 78G, and 78B have a contact angle of 40° or less with respect to the polar solvent contained in the precursor solution when the precursor solution is applied. As a result, the grain size of the ion crystals contained in the light-emitting layers 34R, 34G and 34B can be reduced, the film thickness of the light-emitting layers 34R, 34G and 34B can be made uniform, and the light-emitting layers 34R, 34G and 34B can be made uniform. leakage can be suppressed.

According to the fourth embodiment, the contact angle of the formation surfaces of the light emitting layers 34R, 34G and 34B with respect to the polar solvent can be reduced.

The present disclosure is not limited to the above embodiments, but has substantially the same configuration, the same effect, or the same purpose as the configuration shown in the above embodiment. can be replaced with

Reference Signs List 1 display device 11 pixel 21R, 21G, 21B light emitting element 31 substrate 32 first electrode 33 first charge transport layer 33Ra, 33Ga, 33Ba first region,
33Rb, 33Gb, 33Bb second region 34R, 34G, 34B light emitting layer 35 second charge transport layer 36 second electrode 37R, 37G, 37B surface decorative layer 38R, 38G, 38B other first charge transport layer, 41 luminescent material, 51 ion crystal, 52 quantum dot, 61 core, 62 shell, 63 halogen anion, 72R, 72G, 72B organic compound layer, 72Ra, 72Ga, 72Ba first organic compound portion, 72Rb, 72Gb, 72Bb second organic compound portion 73R, 73G, 73B photoresist layer 74R, 74G, 74B photoresist pattern 75R, 75G, 75B organic compound pattern 76R, 76G, 76B ion crystal layer 76Ra, 76Ga, 76Ba first part, 76Rb, 76Gb, 76Bb second part, 78R, 78G, 78B charge-transporting material layer, 78Ra, 78Ga, 78Ba first part, 81 phosphonic acid, 82 first hydroxyl group, 83 O- group, 84 proton, 85 hydroxyl group, 86 H ₂ ⁺ O group, 87 Ti atom, 88 second hydroxyl group, 89 O ^- group, 90 proton, 91 μ oxo bridge, 92 OH ⁺ bridge, 93 oxygen atom, 94 hydroxyl group, 101 high density phosphonic acid self-assembled membrane (SAM), 102 low density silane SAM membrane.

Claims (25)

a) forming an underlayer having a surface;
b) forming an organic compound pattern comprising an organic compound over a first region included in said surface;
c) applying a precursor solution containing a first solvent and an ion crystal precursor dispersed in the first solvent onto the organic compound pattern and onto the second region included in the surface to form a precursor; forming a body solution layer;
d) volatilizing the first solvent from the precursor solution layer to form a first portion disposed in contact with the organic compound pattern and a second portion disposed in contact with the second region; forming an ionic crystal layer comprising the ionic crystal comprising the portion of 2;
e) dissolving the organic compound pattern in a second solvent having a polarity lower than that of the first solvent to remove the first portion;
A method for producing an ionic crystal pattern comprising: a) forming an underlayer having a surface;
b) forming an organic compound pattern comprising an organic compound over a first region included in said surface;
c) dimethylsulfoxide, N,N-dimethylformamide, N,N'-dimethylpropylene urea, dimethylacetamide, N-methylpyrrolidone, gamma- A precursor solution layer containing a first solvent containing at least one selected from the group consisting of butyrolactone, propylene carbonate and acetonitrile and an ion crystal precursor dispersed in the first solvent is applied to form a precursor solution layer. forming a
d) volatilizing the first solvent from the precursor solution layer to form a first portion disposed in contact with the organic compound pattern and a second portion disposed in contact with the second region; forming an ionic crystal layer comprising the ionic crystal comprising the portion of 2;
e) dissolving the organic compound pattern in a second solvent containing at least one selected from the group consisting of hexane, octane, cyclohexane, toluene, xylene, chlorobenzene, ethyl acetate and butyl acetate to form the first portion; removing;
A method for producing an ionic crystal pattern comprising: 3. The method for producing an ionic crystal pattern according to claim 1, wherein the lower layer contains an inorganic compound. the inorganic compound comprises ZnO and a dopant doped into the ZnO;
The dopant contains at least one selected from the group consisting of Al, Ag, In and Ga,
4. The method for producing an ionic crystal pattern according to claim 3, wherein the content of the dopant in the total of the ZnO and the dopant is 0.5% by weight or more and 5% by weight or less. Said step b) is
b-1) an organic compound layer comprising a first organic compound portion disposed on the first region and a second organic compound portion disposed on the second region, and containing the organic compound; forming a
b-2) removing the second organic compound portion to form the organic compound pattern by O ₂ plasma etching to reduce the contact angle of the second region to the first solvent;
The method for producing an ionic crystal pattern according to claim 3 or 4, comprising: 6. The ionic crystal pattern according to any one of claims 3 to 5, wherein the second region has a contact angle of 40° or less with respect to the first solvent when step c) is performed. Production method. f) forming a surface decoration layer for decorating the second region before step c);
3. The method for producing an ionic crystal pattern according to claim 1, wherein in the step c), the precursor solution is applied onto the organic compound pattern and onto the surface decorative layer. 8. The method for producing an ionic crystal pattern according to claim 7, wherein the step f) forms the surface decorative layer by bringing a surface modifier into contact with the second region. Said step b) is
b-1) an organic compound layer comprising a first organic compound portion disposed on the first region and a second organic compound portion disposed on the second region, and containing the organic compound; forming a
b-2) removing the second organic compound portion by O ₂ plasma etching to form the organic compound pattern;
with
9. The method for producing an ionic crystal pattern according to claim 7, wherein said step f) is performed after said step b-2). 10. The ionic crystal pattern according to any one of claims 1 to 9, wherein the surface of the surface decorative layer has a contact angle of 40° or less with respect to the first solvent when step c) is performed. manufacturing method. g) prior to step c), a third solvent having a higher polarity than the second solvent and dispersed in the third solvent on the organic compound pattern and on the second region; a step of applying a charge-transporting material solution containing a charge-transporting material having charge-transporting properties to form a charge-transporting material solution layer;
h) volatilizing the third solvent from the charge-transporting material solution layer to form a charge-transporting material layer containing the charge-transporting material;
with
3. The method for producing an ionic crystal pattern according to claim 1, wherein in the step c), the precursor solution is applied onto the charge-transporting material layer. The third solvent includes water, methanol, acetone, acetonitrile, dimethylsulfoxide, N,N-dimethylformamide, N,N'-dimethylpropylene urea, dimethylacetamide, N-methylpyrrolidone, gamma-butyrolactone, propylene carbonate and acetonitrile. The method for producing an ionic crystal pattern according to claim 11, comprising at least one selected from the group consisting of: 13. Production of an ionic crystal pattern according to claim 11 or 12, wherein the surface of the charge-transporting material layer has a contact angle of 40° or less with respect to the first solvent when step c) is performed. Method. The precursor solution contains quantum dots dispersed in the first solvent,
The method for producing an ionic crystal pattern according to any one of claims 1 to 13, wherein the ionic crystal layer contains the quantum dots. The ionic crystal contains a halide perovskite compound,
15. The method for producing an ionic crystal pattern according to claim 14, wherein the quantum dots include quantum dots having a halogen-bonded surface. a substrate;
a first electrode disposed on the substrate;
a second electrode disposed on the substrate;
a light-emitting layer disposed between the first electrode and the second electrode, having an average thickness of 1.2 times or more at an end portion and containing an ionic crystal;
A light-emitting element. 17. The light-emitting device of claim 16, further comprising a charge transport layer disposed between the first electrode and the light-emitting layer, in direct contact with the light-emitting layer, and comprising an inorganic compound. the inorganic compound comprises ZnO and a dopant doped into the ZnO;
The dopant contains at least one selected from the group consisting of Al, Ag, In and Ga,
18. The light emitting device according to claim 17, wherein the content of the dopant in the total of the ZnO and the dopant is 0.5% by weight or more and 5% by weight or less. a charge transport layer disposed between the first electrode and the light-emitting layer and having a surface;
a surface decoration layer that decorates the surface and is in direct contact with the light-emitting layer;
17. The light emitting device of claim 16, comprising: 20. The light-emitting device according to claim 19, wherein the surface decoration layer contains at least one selected from the group consisting of amino groups, hydroxyl groups, carboxylic acids and ethylene glycol chains. 21. The light emitting device according to claim 19 or 20, wherein the charge transport layer contains an oxide. a charge transport layer disposed between the first electrode and the light-emitting layer;
another charge-transporting layer disposed between the charge-transporting layer and the light-emitting layer, in direct contact with the light-emitting layer, and containing a charge-transporting material different from the charge-transporting material contained in the charge-transporting layer; ,
17. The light emitting device of claim 16, comprising: 23. The light emission according to claim 22, wherein the other charge transport layer contains at least one selected from the group consisting of poly(3,4-ethylenedioxythiophene)/polystyrenesulfonic acid, polyethyleneimine and ethoxylated polyethyleneimine. element. 24. The light emitting device according to any one of claims 16 to 23, wherein said ionic crystal comprises a halide perovskite compound. 25. The light-emitting device according to any one of claims 16 to 24, wherein the light-emitting layer comprises quantum dots having surfaces bonded with the ionic crystals and halogens.

Images