Preparation method and application of semiconductor nanocrystalline pattern layer

Abstract

The invention provides a preparation method and application of a semiconductor nanocrystalline pattern layer. The method comprises the steps that an aqueous solution containing semiconductor nanocrystals is provided, the surfaces of the semiconductor nanocrystals comprise water-soluble ligands containing COO <->, and the aqueous solution further comprises a photoacid generator; the aqueous solution is arranged on a base material layer to form a layer of wet film, a patterned optical mask plate is arranged above the base material layer, illumination is applied through the optical mask plate, so that the wet film is patterned, the photoacid generator generates hydrogen ions under illumination, the hydrogen ions and COO <-> form carboxyl groups, and the surface of the semiconductor nanocrystal changes and precipitates; and removing the optical mask and stopping illumination, cleaning the exposed semiconductor nanocrystal layer with water, separating the unexposed semiconductor nanocrystal from the base material layer and removing the unexposed semiconductor nanocrystal to obtain the target semiconductor nanocrystal pattern layer. The method gets rid of dependence on organic solvents, is more environment-friendly and is suitable for mass production.

Description

Technical Field

[0001] This application relates to the technical field of semiconductor nanocrystals, and more specifically, to a method for preparing a semiconductor nanocrystal pattern layer, a semiconductor nanocrystal composition, and a method for preparing a semiconductor nanocrystal light-emitting device. Background Art

[0002] Semiconductor nanocrystals (such as quantum dots) non-lithographic technology gets rid of the dependence on photoresist for semiconductor nanocrystal lithographic patterning, and realizes direct lithography by modifying the ligands of semiconductor nanocrystals or adding small molecule photosensitizers to the semiconductor nanocrystal solution. The most maturely studied and most developed process route is the ligand-crosslinked quantum dot non-lithographic technology. Its most typical implementation scheme is to add an artificially designed and synthesized photosensitive ligand (or an additive that is not a ligand) to quantum dots with long-chain organic ligands on the surface (which can be called oil-phase quantum dots) dispersed in a non-polar organic solvent, and then coat this oil-phase quantum dot on a substrate, and expose it through an optical mask template with a hollowed-out pattern. The photosensitive molecules at the exposed area undergo an optical reaction to generate chemically active groups, and the latter combine with the original organic ligands of the quantum dots to cause ligand crosslinking, so that the quantum dots at the exposed area are crosslinked with each other. The crosslinked quantum dots cannot be dispersed into the developer (usually the same as the solvent of the original quantum dot solution), while the quantum dots at the unexposed area can be dispersed into the developer because they have not changed. In this way, a quantum dot pattern left on the substrate can be obtained. The existing technology is still difficult to be truly applied, and one of the important disadvantages is the difficulty in getting rid of the dependence on organic solvents. Summary of the Invention

[0003] The purpose of this application is to provide a method for preparing a semiconductor nanocrystal pattern layer and a method for preparing a light-emitting device containing a semiconductor nanocrystal pattern layer, a semiconductor nanocrystal composition, which gets rid of the dependence on organic solvents, is more environmentally friendly and suitable for mass production.

[0004] According to the first aspect of this application, a method for preparing a semiconductor nanocrystal pattern layer is provided. The preparation method includes: providing an aqueous solution containing semiconductor nanocrystals, the surface of the semiconductor nanocrystals includes a water-soluble ligand containing COO - ; the aqueous solution further includes a photoacid generator; setting the aqueous solution on a substrate layer to form a wet film, setting a patterned optical mask template above the substrate layer, and applying light through the optical mask template to pattern the wet film, wherein the photoacid generator generates hydrogen ions under light, and the hydrogen ions and COO - form carboxyl groups, so that the surface of the semiconductor nanocrystals changes and precipitates; removing the optical mask template and stopping the light irradiation, washing the exposed semiconductor nanocrystal layer with water, and the unexposed semiconductor nanocrystals are removed from the substrate layer to obtain the target semiconductor nanocrystal pattern layer.

[0005] Further, the water-soluble ligand is selected from at least one of cysteine, glutamic acid, citric acid, malonic acid, butanetetracarboxylic acid, or a molecule having the structure of Chemical Formula 1 below; Chemical Formula 1: R1-R2-COOH, where R1 is a mercapto group, an amino group, or a carboxyl group, and R2 is an alkyl group having <12 carbon atoms.

[0006] Further, the solvent of the aqueous solution includes one or more of water, ethanol, ethylene glycol, propylene glycol, glycerol, n-propanol, isopropanol, butanediol, n-butanol, isobutanol, tert-butanol, isopentanetetraol, and pentaerythritol.

[0007] Further, the photoacid generator is selected from one or more of diazonium salts, organic polyhalides, onium salts, and sulfonic acid esters.

[0008] Further, the method of forming a wet film by disposing the aqueous solution on the substrate layer is selected from one of spin coating, blade coating, spraying, inkjet printing, and transfer printing.

[0009] Further, the preparation of the aqueous solution containing semiconductor nanocrystals includes: preparing oil-soluble semiconductor nanocrystals, performing ligand exchange on the oil-soluble semiconductor nanocrystals with a water-soluble ligand, separating and purifying the semiconductor nanocrystals after the ligand exchange is completed and dispersing them in a solvent to obtain an intermediate solution, and adding a photoacid generator to the intermediate solution.

[0010] Further, in the aqueous solution containing semiconductor nanocrystals, the mass concentration of the semiconductor nanocrystals is 1-100 mg / mL, and the mass concentration of the photoacid generator is 0.01-1 mg / mL.

[0011] Further, in the aqueous solution containing semiconductor nanocrystals, the mass ratio of the semiconductor nanocrystals to the photoacid generator is 50-500.

[0012] Further, in the aqueous solution containing semiconductor nanocrystals, the density of the water-soluble ligand on the surface of the semiconductor nanocrystals is not less than 1 nm -2 ; optionally, the density of the water-soluble ligand on the surface of the semiconductor nanocrystals is 4-5 nm -2 .

[0013] According to the second aspect of the present application, a semiconductor nanocrystal composition is provided. The semiconductor nanocrystal composition includes semiconductor nanocrystals. The surface of the semiconductor nanocrystals includes a water-soluble ligand containing COO-, a water-soluble solvent, and a photoacid generator. The photoacid generator can generate hydrogen ions under light irradiation.

[0014] According to the third aspect of the present application, a method for preparing a semiconductor nanocrystal light-emitting device is provided. The preparation method includes the method for preparing the semiconductor nanocrystal pattern layer as described in any one of the above. Description of the Drawings

[0015] The accompanying drawings forming a part of this application are used to provide a further understanding of this application. The schematic embodiments and descriptions thereof of this application are used to explain this application and do not constitute an improper limitation to this application. In the drawings:

[0016] Figure 1 It is a schematic diagram of the principle of a specific embodiment of this application.

[0017] Figure 2 It is a Zeta potential diagram of the quantum dot composition of Example 1.

[0018] Figure 3 It is a bright-field microscope photograph (without excitation light) of the quantum dot pattern layer of Example 1.

[0019] Figure 4 It is a microscope photograph (excited by a 365 nm LED flashlight) of the quantum dot pattern layer of Example 1.

[0020] Figure 5 It is a microscope photograph when the patterned QLED device of Example 2 emits light.

[0021] Figure 6 It is a microscope photograph (excited by a 365 nm LED flashlight) of the quantum dot pattern layer of Example 3.

[0022] Figure 7 It is a microscope photograph (excited by a 365 nm LED flashlight) of the quantum dot pattern layer of Example 4.

[0023] Figure 8 It is a microscope photograph (excited by a 365 nm LED flashlight) of the quantum dot pattern layer of Example 5.

[0024] Figure 9 It is a microscope photograph (excited by a 365 nm LED flashlight) of the quantum dot pattern layer of Example 6.

[0025] Note that in the embodiments described below, sometimes the same reference numerals are used commonly between different drawings to represent the same parts or parts with the same functions, and their repeated descriptions are omitted. In some cases, similar reference numerals and letters are used to represent similar items. Therefore, once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0026] For ease of understanding, the positions, sizes, ranges, etc. of the various structures shown in the drawings and the like sometimes do not represent the actual positions, sizes, ranges, etc. Therefore, this application is not limited to the positions, sizes, ranges, etc. disclosed in the drawings and the like. Detailed Embodiments

[0027] Various exemplary embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be noted that: Unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present application.

[0028] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way a limitation on the present application or its application or use. That is, the structures and methods herein are shown in an exemplary manner to illustrate different embodiments of the structures and methods in the present application. However, those skilled in the art will understand that they merely illustrate the exemplary manners in which the present application can be implemented, rather than an exhaustive manner. In addition, the drawings are not necessarily drawn to scale, and some features may be enlarged to show details of specific components.

[0029] In addition, technologies, methods, and devices known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies, methods, and devices should be regarded as part of the authorization specification.

[0030] In all examples shown and discussed herein, any specific values should be construed as merely exemplary and not as a limitation. Thus, other examples of the exemplary embodiments may have different values.

[0031] In the specification and claims, words such as "left", "right", "front", "rear", "top", "bottom", "upper", "lower", "high", "low", etc., if any, are used for descriptive purposes and not necessarily to describe an invariant relative position. It should be understood that such words are interchangeable under appropriate circumstances, such that the embodiments of the present application described herein, for example, can operate in other orientations different from those shown or otherwise described herein. For example, when the device in the drawings is inverted, a feature originally described as "above" other features can then be described as "below" other features. The device can also be oriented in other ways (rotated 90 degrees or in other orientations), and the relative spatial relationships will be correspondingly interpreted at this time.

[0032] In the specification and claims, when an element is referred to as being "on", "attached" to, "connected" to, "coupled" to, or "operatively coupled" to another element, etc., the element can be directly on, directly attached to, directly connected to, directly coupled to, or directly operatively coupled to the other element, or there can be one or more intervening elements. In contrast, when an element is referred to as being "directly on", "directly attached" to, "directly connected" to, "directly coupled" to, or "directly operatively coupled" to another element, there will be no intervening elements. In the specification and claims, a feature being arranged "adjacent" to another feature can mean that the feature has a portion that overlaps with the adjacent feature or a portion that is above or below the adjacent feature.

[0033] As used herein, the term "exemplary" means "serving as an example, instance, or illustration", rather than as a "model" to be precisely replicated. Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Moreover, the present application is not limited by any theory expressed or implied in the technical field, background art, summary of the invention, or detailed description.

[0034] As used herein, the term "substantially" means including any minor variations due to design or manufacturing defects, tolerances of devices or elements, environmental effects, and / or other factors. The term "substantially" also allows for differences from a perfect or ideal situation due to parasitic effects, noise, and other practical considerations that may exist in an actual implementation.

[0035] In addition, for reference purposes only, terms such as "first", "second", etc. may also be used herein, and are thus not intended to be limiting. For example, unless the context clearly indicates otherwise, the words "first", "second", and other such numerical words referring to a structure or element do not imply an order or sequence.

[0036] It should also be understood that when the term "comprising / including" is used herein, it specifies the presence of the stated features, integers, steps, operations, units, and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, units, and / or components and / or combinations thereof.

[0037] In the present application, the term "provide" is used broadly to cover all ways of obtaining an object, so "providing an object" includes, but is not limited to, "purchasing", "preparing / manufacturing", "arranging / setting", "installing / assembling", and / or "ordering" the object, etc.

[0038] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. The terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the present application. As used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0039] As described in the background art, almost all of the currently available quantum dot lithography technologies are based on organic solvent systems. Most of these organic solvents are toxic and harmful, which is not conducive to large-scale production and hinders the practical application of these technologies. Developing a water-based quantum dot lithography technology without glue is an ideal solution to solve this problem. If the quantum dot composition is formulated in the form of an aqueous solution and the developer used in lithography is also an aqueous solution, the entire lithography process will be completely green and pollution-free, with greater application potential.

[0040] Based on the above considerations, according to the first aspect of the present application, a method for preparing a semiconductor nanocrystal pattern layer is provided. An aqueous solution containing semiconductor nanocrystals is provided. The surface of the semiconductor nanocrystals includes a water-soluble ligand containing COO - and the aqueous solution further includes a photoacid generator; the aqueous solution is disposed on a substrate layer to form a wet film, a patterned optical mask is disposed above the substrate layer, and light is applied through the optical mask to pattern the wet film, wherein the photoacid generator generates hydrogen ions under light irradiation, and the hydrogen ions and COO - form carboxyl groups, causing a change in the surface of the semiconductor nanocrystals and precipitation; the optical mask is removed and the light irradiation is stopped, and the exposed semiconductor nanocrystal layer is washed with water, and the unexposed semiconductor nanocrystals are detached from the substrate layer and removed to obtain the target semiconductor nanocrystal pattern layer. The above preparation method utilizes the loss of colloidal stability of water-based quantum dots in water-based solvents and cannot be dispersed in water-based solvents, and through water washing and development, a green and environmentally friendly process is achieved.

[0041] The above semiconductor nanocrystals may be quantum dots or semiconductor nanocrystals of other shapes.

[0042] Figure 1 Shows a change process of the quantum dot surface ligand, including the conversion of oil-soluble quantum dots to water-soluble quantum dots, which become insoluble in the aqueous solution after light irradiation.

[0043] In some embodiments, the water-soluble ligand is selected from at least one of cysteine, glutamic acid, citric acid, malonic acid, butanetetracarboxylic acid, or a molecule having the structure of Chemical Formula 1 below; Chemical Formula 1: R1-R2-COOH, wherein R1 is a mercapto group, an amino group or a carboxyl group, and R2 is an alkyl group having <12 carbon atoms. In some embodiments, R2 is an alkyl group having <10 carbon atoms.

[0044] The solvent of the aqueous solution is such that the semiconductor nanocrystals can be stably dispersed. In some embodiments, the solvent of the aqueous solution includes one or more of water, ethanol, ethylene glycol, propylene glycol, glycerol, n-propanol, isopropanol, butanediol, n-butanol, isobutanol, tert-butanol, isopentanetetraol, and pentaerythritol. In some embodiments, when the aqueous solution includes ethanol, the volume fraction of ethanol in the solvent does not exceed 50%.

[0045] In some embodiments, the photoacid generator is selected from one or more of diazonium salts, organic polyhalides, onium salts, and sulfonic acid esters.

[0046] In some embodiments, the photoacid generator is selected from at least one of diazonium sulfate, diazonium hydrochloride, diazonium sulfonate, diazonium hexafluorophosphate, diazonium hexafluoroantimonate, diazonium perchlorate, diphenylamine formaldehyde resin, trichloroacetophenone, tribromomethyl phenyl sulfone, 4-phenoxydichloroacetophenone, triazine derivatives (such as 4,6-bis(trichloromethyl)-1,3,5-triazine derivatives), phosphonium salts, arsonium salts, selenonium salts, sulfonium salts (such as triphenylsulfonium trifluoromethanesulfonate, 2,4-dihydroxyphenyl dimethylsulfonium trifluoromethanesulfonate), and iodonium salts, 1-diazo-2-naphthol-4-sulfonic acid, N-hydroxynaphthalimide trifluoromethanesulfonate, N-p-toluenesulfonyloxyphthalimide, N-trifluoromethanesulfonyloxysuccinimide, N-trifluoromethanesulfonyloxynaphthalenedicarboximide, dinitrobenzyl p-toluenesulfonate, α-hydroxymethyl benzoin monosulfonate, α,α-bis(arylsulfonyl) diazomethane, and α-carbonyl-α-sulfonyl diazomethane.

[0047] In some embodiments, the method of forming a wet film by disposing the aqueous solution on a substrate layer is selected from one of spin coating, blade coating, spraying, inkjet printing, and transfer printing. In some embodiments, the substrate layer is a substrate with electrodes.

[0048] In some embodiments, the preparation of the aqueous solution containing semiconductor nanocrystals includes: preparing oil-soluble semiconductor nanocrystals, performing ligand exchange on the oil-soluble semiconductor nanocrystals with a water-soluble ligand, separating and purifying the semiconductor nanocrystals after the ligand exchange is completed and dispersing them in a solvent to obtain an intermediate solution, and adding a photoacid generator to the intermediate solution. Specific ligand exchange conditions can refer to the prior art, and some oil-soluble ligands may remain on the surface of the semiconductor nanocrystals after the ligand exchange is completed.

[0049] In some embodiments, in the aqueous solution containing semiconductor nanocrystals, the mass concentration of the semiconductor nanocrystals is 1-100 mg / mL, and the mass concentration of the photoacid generator is 0.01-1 mg / mL.

[0050] In some embodiments, in the aqueous solution containing semiconductor nanocrystals, the mass ratio of the semiconductor nanocrystals to the photoacid generator is 50-500.

[0051] In some embodiments, in an aqueous solution containing semiconductor nanocrystals, the density of the water-soluble ligand on the surface of the semiconductor nanocrystals (calculated according to its surface area) is not less than 1 nm -2 , so as to be better dispersed in the aqueous solution; optionally, the density of the water-soluble ligand on the surface of the semiconductor nanocrystals is 4-5 nm -2 .

[0052] According to a second aspect of the present application, a semiconductor nanocrystal composition is provided. The semiconductor nanocrystal composition includes semiconductor nanocrystals, the surface of the semiconductor nanocrystals includes a water-soluble ligand containing COO-, a water-soluble solvent, and a photoacid generator. The photoacid generator can generate hydrogen ions under light irradiation. The above composition can utilize the loss of colloidal stability of aqueous quantum dots in an aqueous solvent during use and cannot be dispersed in the aqueous solvent, and realizes a green and environmentally friendly process through water washing and development.

[0053] According to a third aspect of the present application, a method for preparing a semiconductor nanocrystal light-emitting device, the preparation method includes the method for preparing the semiconductor nanocrystal pattern layer according to any one of the above.

[0054] In some embodiments, the above semiconductor nanocrystal pattern layer is a photoluminescent layer.

[0055] In some other embodiments, the above semiconductor nanocrystal pattern layer is an electroluminescent layer. The semiconductor nanocrystal light-emitting device includes a light-emitting layer. However, the semiconductor nanocrystal light-emitting device may further include an auxiliary light-emitting layer configured to increase the light-emitting efficiency in addition to the main light-emitting layer including a light-emitting material that emits light of a predetermined color. In some embodiments, the light-emitting layer may have a stacked structure of multiple sub-light-emitting layers, and the multiple sub-light-emitting layers have different light-emitting material components.

[0056] The semiconductor nanocrystal light-emitting device may include a hole transport region disposed between the first electrode and the light-emitting layer. The hole transport region may include at least one of a hole injection layer, a hole transport layer, an auxiliary light-emitting layer, and an electron blocking layer. For example, the hole transport region may include a hole injection layer and a hole transport layer sequentially stacked on the first electrode.

[0057] The semiconductor nanocrystal light-emitting device may include an electron transport region disposed between the light-emitting layer and the second electrode. The electron transport region may include at least one of a hole blocking layer, an electron transport layer, and an electron injection layer. For example, the electron transport region may include an electron transport layer and an electron injection layer disposed on the light-emitting layer, but the embodiments supported by the present application are not limited thereto. The electron transport region may have a single-layer structure formed of a single material, a single-layer structure formed of multiple different materials, or a multi-layer structure having multiple layers formed of multiple different materials.

[0058] In the following, the embodiments will be described in more detail with reference to specific examples. However, they are exemplary examples of the content of the present application, and the content of the present application is not limited thereto.

[0059] Example 1: Patterning of CdSe / ZnS Quantum Dots with Mercaptopropionic Acid (MPA) as Ligand

[0060] Ligand exchange. Weigh potassium hydroxide (KOH) and MPA to prepare an aqueous solution with a concentration of 0.2 M for both of them (abbreviated as MPA-KOH solution). 20 mg of CdSe / ZnS QD is dispersed in 1 mL of toluene. Take 1 mL of the above MPA-KOH solution and mix it with the QD solution. Stir at 60 °C until the upper layer becomes colorless and transparent, and the quantum dots are transferred to the lower layer. Stop stirring, suck out the upper layer solution and discard it. Add a mixture of 2 mL of ethanol and 3 mL of ethyl acetate to the lower aqueous solution to precipitate the QD. After centrifugation, discard the supernatant. The precipitate is CdSe / ZnS QD with MPA as the ligand. Disperse the precipitate in 1 mL of water, repeat the precipitation - centrifugation operation once, and then disperse the QD in water to obtain a 20 mg / mL aqueous solution. The Zeta potential diagram of this QD aqueous solution is shown in Figure 2 , indicating that the surface of the QD is negatively charged after ligand exchange.

[0061] Lithography. An aqueous solution of CdSe / ZnS QD with MPA as ligand (20 mg / mL) and an aqueous solution of 1-diazo-2-naphthol-4-sulfonic acid (DNS) (20 mg / mL) are mixed according to a QD:DNS mass ratio of 150:1. Spin-coat the above QD-DNS solution at 3000 rpm for 30 s to form a film on the substrate (QD:DNS film). Then, cover an optical mask with a hollow target pattern on the QD:DNS film and expose it with an i-line light source generated by a low-pressure mercury lamp at 1000 mJ / cm 2 . Subsequently, rinse the QD film with pure water for more than 30 seconds to elute the quantum dots in the unexposed area, and obtain a quantum dot pattern identical to the hollow pattern on the optical mask. The microscope photos are shown in Figure 3 、 Figure 4 .

[0062] Example 2: Fabrication of Inverted Bottom-Emitting Patterned QLED Devices

[0063] Ligand exchange. Prepare 1 mL of a toluene solution containing 1 mmol each of MPA and mercaptoundecanoic acid (MUA), add it to 4 mL of a 5 mg / mL CdSe / ZnS QD toluene solution, shake at room temperature until all the QD precipitates, centrifuge, wash the precipitate twice with toluene, dry the solvent, add 1 mL of water, and adjust the pH of the solution to 13 with tetramethylammonium hydroxide (TMAH) to fully disperse the QD to obtain a QD aqueous solution.

[0064] The device uses an inverted structure. The cleaned indium tin oxide (ITO) glass substrate is first treated with ozone for 10 minutes. ZnMgO nanoparticles (20 mg / mL ethanol solution) are spin-coated at 4000 rpm for 30 seconds and baked at 100 °C for 10 minutes. The aqueous solution of CdSe / ZnS QDs with the above-mentioned MPA-MUA mixed ligands (20 mg / mL) and the aqueous solution of 1-diazo-2-naphthol-4-sulfonic acid (DNS) the same as in Example 1 are mixed according to the QD:DNS mass ratio of 150:1, spin-coated at 3000 rpm for 30 seconds, the optical mask template is aligned and overpressed on the mask alignment device, and exposed with an i-line light source generated by a low-pressure mercury lamp at 1000 mJ / cm 2 . Subsequently, the quantum dot film is rinsed with pure water for more than 30 seconds to elute the quantum dots in the unexposed area. After lithography, the substrate is transferred to a glove box and baked at 110 °C for 10 minutes. Ethoxylated polyethyleneimine (PEIE, 0.4% ethylene glycol monomethyl ether solution) is spin-coated at 3000 rpm for 30 seconds and baked at 100 °C for 10 minutes. Poly[(9,9-dioctylfluorene-2,7-diyl)-co-(4,4'-(N-(4-sec-butylphenyl)diphenylamine)] (TFB, 8 mg / mL chlorobenzene solution) is spin-coated at 3000 rpm for 30 seconds and baked at 120 °C for 10 minutes. Transfer to an evaporation chamber, evacuate to 10 -7 Torr, and then deposit 10 nm of MoO3 and 100 nm of Ag successively to complete the device preparation. The microscope photograph is shown in Figure 5 .

[0065] Example 3: Patterning of aqueous InP / ZnS quantum dots

[0066] Ligand exchange. Take 1 mL of 0.2 M aqueous sodium citrate solution and add it to 1 mL of InP / ZnS QD toluene solution with a concentration of 20 mg / mL. Stir at room temperature overnight until the upper layer becomes colorless and transparent and the quantum dots transfer to the lower layer. Stop stirring, suck out the upper layer solution and discard it. Add a mixture of 2 mL of ethanol and 3 mL of ethyl acetate to the lower aqueous solution to precipitate the QDs, and discard the supernatant after centrifugation. The precipitate is InP / ZnS QDs with citrate as the ligand. Disperse the precipitate in 1 mL of water, repeat the precipitation-centrifugation operation once, and then disperse the QDs in water to obtain a 20 mg / mL QD aqueous solution.

[0067] Lithography. The aqueous solution of InP / ZnS QDs with citrate as the ligand (20 mg / mL) and the DNS aqueous solution the same as in Example 1 are mixed according to the QD:DNS mass ratio of 200:1. The above QD-DNS solution is spin-coated at 3000 rpm for 30 s to form a film on the substrate. Then, an optical mask template with a hollow target pattern is overpressed on the QD:DNS film, and exposed with an i-line light source generated by a low-pressure mercury lamp at 1000 mJ / cm 2Subsequently, the QD film was rinsed with pure water for more than 30 seconds to elute the quantum dots in the unexposed area, obtaining a quantum dot pattern identical to the hollow pattern on the optical mask. See the microscope photograph in Figure 6 。

[0068] Example 4: Aqueous-phase quantum dot patterning based on cysteine ligand

[0069] Ligand exchange. 1 mL of 0.2 M cysteine aqueous solution was added to 1 mL of CdSe / ZnS QD toluene solution with a concentration of 20 mg / mL. Stirred overnight at room temperature until the upper layer became colorless and transparent and the quantum dots were transferred to the lower layer. Stop stirring, suck out the upper layer solution and discard it. Add a mixture of 2 mL of ethanol and 3 mL of ethyl acetate to the lower aqueous solution to precipitate the QDs, centrifuge and discard the supernatant. Disperse the precipitate in 1 mL of water, adjust the pH to alkaline with TMAH until the QDs completely form a clear solution, repeat the precipitation-centrifugation operation once, and then disperse the QDs in water to obtain a 20 mg / mL QD aqueous solution.

[0070] Lithography. The above CdSe / ZnS QD aqueous solution (20 mg / mL) with cysteine as the ligand was mixed with the same DNS aqueous solution as in Example 1 according to the mass ratio of QD:DNS of 150:1. The above QD-DNS solution was spin-coated on the substrate at 3000 rpm for 30 s to form a film. Then, an optical mask with a hollow target pattern was pressed onto the QD:DNS film, and exposed with an i-line light source generated by a low-pressure mercury lamp at 1000 mJ / cm 2 Subsequently, the QD film was rinsed with pure water for more than 30 seconds to elute the quantum dots in the unexposed area, obtaining a quantum dot pattern identical to the hollow pattern on the optical mask. See the microscope photograph in Figure 7 。

[0071] Example 5: Aqueous-phase quantum dot patterning using an ionic photoacid generator (specifically TPST)

[0072] A CdSe / ZnS QD aqueous solution (20 mg / mL, 1 mL) with MPA as the ligand was obtained by the same steps as in Example 1, and 1 mg of triphenylsulfonium trifluoromethanesulfonate (TPST) was added thereto. The cleaned glass substrate was first treated with ozone for 10 minutes, and the above QD solution was spin-coated on the substrate at 3000 rpm for 30 s to form a film. Then, an optical mask with a hollow target pattern was pressed onto the QD film, and exposed with a deep ultraviolet light source generated by a low-pressure mercury lamp at 400 mJ / cm 2 Subsequently, the glass substrate was immersed in pure water for 30 seconds, and then the QD film was rinsed with pure water for more than 30 seconds to elute the quantum dots in the unexposed area, obtaining a quantum dot pattern identical to the hollow pattern on the optical mask. See the microscope photograph in Figure 8 。

[0073] Example 6: Quantum Dot Patterning in Alcohol-Containing Aqueous Solution

[0074] CdSe / ZnS QDs with MPA as the ligand were obtained by the same procedure as in Example 1. First, 0.5 mL of an aqueous solution with a concentration of 40 mg / mL was prepared. Separately, 0.5 mL of an ethanol solution of N-hydroxynaphthalimide trifluoromethanesulfonate (HNT) with a concentration of 4 mg / mL was prepared and mixed with the above aqueous solution to obtain a QD solution dispersed in a mixed solvent with a water / ethanol ratio of 1:1. The cleaned glass substrate was first treated with ozone for 10 minutes. The above solution (0.1 mL) was added dropwise while the spinner was rotating at a speed of 3000 rpm, and then spin-coated for 30 s to form a film (QD:HNT film) on the substrate. Then, an optical mask with a hollow target pattern was pressed onto the QD:HNT film, and exposed with an i-line light source generated by a low-pressure mercury lamp at 1000 mJ / cm 2 . Subsequently, the QD film was rinsed with pure water for more than 30 seconds to elute the quantum dots in the unexposed areas, obtaining a quantum dot pattern identical to the hollow pattern on the optical mask. The micrograph is shown in Figure 9 .

[0075] Although some specific embodiments of the present application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and not for limiting the scope of the present application. The various embodiments disclosed herein can be combined arbitrarily without departing from the spirit and scope of the present application. Those skilled in the art should also understand that various modifications can be made to the embodiments without departing from the scope and spirit of the present application. The scope of the present application is defined by the appended claims.

Claims

1. A method for preparing a semiconductor nanocrystal pattern layer, characterized in that, The preparation method includes: providing an aqueous solution containing semiconductor nanocrystals, the surface of the semiconductor nanocrystals including water-soluble ligands containing COO - , and a photoacid generator is further included in the aqueous solution; setting the aqueous solution on a substrate layer to form a wet film, arranging a patterned optical mask above the substrate layer, and applying light through the optical mask, so as to pattern the wet film, wherein the photoacid generator generates hydrogen ions under light irradiation, and the hydrogen ions and COO - form carboxyl groups, so that the surface of the semiconductor nanocrystals changes and precipitates; removing the optical mask and stopping the light irradiation, washing the exposed semiconductor nanocrystal layer with water, and removing the unexposed semiconductor nanocrystals from the substrate layer, thereby obtaining a target semiconductor nanocrystal pattern layer.

2. The preparation method of the semiconductor nanocrystal pattern layer according to claim 1, characterized in that The water-soluble ligand is selected from at least one of cysteine, glutamic acid, citric acid, malonic acid, butanetetracarboxylic acid, or a molecule having the structure of Formula 1 below; Formula 1: R1-R2-COOH, where R1 is a mercapto group, an amino group or a carboxyl group, and R2 is an alkyl group having <12 carbon atoms.

3. The method for preparing the semiconductor nanocrystal pattern layer according to claim 1, wherein The solvent of the aqueous solution includes one or more of water, ethanol, ethylene glycol, propylene glycol, glycerol, n-propanol, isopropanol, butanediol, n-butanol, isobutanol, tert-butanol, isopentanetetraol, pentaerythritol.

4. The method for preparing the semiconductor nanocrystal pattern layer according to claim 1, wherein, The photoacid generator is selected from one or more of diazonium salts, organic polyhalides, onium salts, sulfonic acid esters.

5. The method for preparing the semiconductor nanocrystal pattern layer according to claim 1, wherein The method of forming a wet film by disposing the aqueous solution on a substrate layer is selected from one of spin coating, knife coating, spraying, inkjet printing, transfer printing.

6. The method for preparing a semiconductor nanocrystal pattern layer according to claim 1, wherein The preparation of the aqueous solution containing semiconductor nanocrystals includes: preparing oil-soluble semiconductor nanocrystals, performing ligand exchange on the oil-soluble semiconductor nanocrystals with the water-soluble ligand, separating and purifying the semiconductor nanocrystals after the ligand exchange is completed and dispersing them in a solvent to obtain an intermediate solution, and adding the photoacid generator to the intermediate solution.

7. The method for preparing the semiconductor nanocrystal pattern layer according to claim 1, wherein In the aqueous solution containing semiconductor nanocrystals, the mass concentration of the semiconductor nanocrystals is 1-100 mg / mL, and the mass concentration of the photoacid generator is 0.01-1 mg / mL.

8. The method for preparing the semiconductor nanocrystal pattern layer according to claim 1, characterized in that In the aqueous solution containing semiconductor nanocrystals, the mass ratio of the semiconductor nanocrystals to the photoacid generator is 50-500.

9. The method for preparing a semiconductor nanocrystal pattern layer according to claim 1, wherein, In the aqueous solution containing semiconductor nanocrystals, the density of the water-soluble ligand on the surface of the semiconductor nanocrystals is not less than 1 nm -2 ; Optionally, the density of the water-soluble ligand on the surface of the semiconductor nanocrystals is 4-5 nm -2 .

10. A semiconductor nanocrystal composition, characterized in that, The semiconductor nanocrystal composition includes semiconductor nanocrystals, the surface of the semiconductor nanocrystals includes a water-soluble ligand containing COO-, a water-soluble solvent and a photoacid generator, and the photoacid generator can generate hydrogen ions under light irradiation.

11. A method for preparing a semiconductor nanocrystal light-emitting device, characterized in that, The preparation method includes the preparation method of the semiconductor nanocrystal pattern layer according to any one of claims 1 to 9.

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