Quantum dot film patterning method and application

Abstract

The application provides a quantum dot film patterning method and application. The quantum dot film patterning method comprises the following steps: (1) mixing quantum dots and a photosensitive cross-linking agent to form a thin layer; (2) performing patterned exposure treatment on the thin layer to obtain a patterned quantum dot film; wherein the surface of the quantum dots is provided with a ligand containing a carbon-hydrogen bond; and the photosensitive cross-linking agent has a structure shown in formula I: in formula I, R1 is an electron-donating group; n is greater than or equal to 2; and X is a group that does not affect the generation of a singlet intermediate. The quantum dot film patterning method can realize the high-efficiency patterning of quantum dots of different types and compositions in air, has the advantages of high resolution, strong universality and suitability for large-scale industrial production, and can be used for preparing optoelectronic devices such as quantum dot LEDs, and can maintain the photoelectric performance of the quantum dot material to a great extent.

Description

Technical Field

[0001] The present invention belongs to the field of optoelectronic technology, and in particular relates to a method for preparing a patterned quantum dot film and the construction of a light-emitting display device. Background Art

[0002] Quantum dots (QDs) are semiconductor nanocrystals with a size smaller than the Bohr radius, with a common size of 2-20nm. They are composed of an inorganic semiconductor core and surface ligands, and have obvious volume effects, surface effects, size effects and other characteristics. Their luminescence wavelength can be controlled and adjusted according to their size, and the emission half-peak width is narrow and the color gamut is wide. At the same time, compared with traditional semiconductor materials such as silicon, quantum dots can form stable colloidal solutions, and low-cost, large-area, high-efficiency optoelectronic devices can be constructed using the solution method.

[0003] In the field of optoelectronic devices, quantum dots are typically used as thin films as the optoelectronic active layer. Patterning methods can achieve micron-scale resolution in quantum dot arrays, offering broad application prospects in high-definition, colorful flat-panel displays or lighting, sensor imaging, and optoelectronic stimulation. Conventional methods for patterning quantum dot thin films have drawbacks. For example, photolithography techniques struggle to ensure compatibility between quantum dots and photoresists, inkjet printing techniques offer limited pattern resolution (>50 microns), and techniques such as electron beam or laser direct writing can damage the optoelectronic properties of the quantum dots themselves.

[0004] In recent years, new patterning methods based on quantum dot surface chemistry have enabled the efficient realization of high-resolution (<5 micron) patterned quantum dot films. However, most of these currently reported methods are implemented under inert gas. When quantum dot patterning is performed in air, problems such as failure to form a pattern or reduced photoelectric performance of the quantum dot film may occur. CN114839835A utilizes photosensitive crosslinking molecules containing diazirine groups (i.e., carbene crosslinking molecules) to achieve patterning of quantum dot films. In a nitrogen environment, singlet carbene intermediates generated by illumination of these crosslinking molecules undergo insertion reactions with carbon-hydrogen bonds in ligands on the quantum dot surface, thereby crosslinking the quantum dots and achieving patterning. However, the higher-energy singlet carbene intermediates (with a net electron spin of S=0) readily convert to triplet states (with a net electron spin of S=1). When exposed to air, the resulting triplet carbene rapidly reacts with oxygen in the air. This side reaction depletes the singlet carbene, preventing the quantum dots from being crosslinked to form a pattern. Furthermore, the impact of the ambient air on the optoelectronic properties of quantum dots during patterning is often overlooked. This is especially true for III-V quantum dots, which are free of heavy metals like cadmium, whose optoelectronic properties are more susceptible to factors such as oxygen. These issues hinder the practical development and application of quantum dot thin film patterning methods for large-scale, low-cost production. Therefore, it is urgently necessary to develop quantum dot thin film patterning methods that can be performed in air without damaging quantum dot performance. Summary of the Invention

[0005] In order to solve the above problems, the purpose of the present invention is to provide a quantum dot thin film patterning method and application, which can achieve efficient patterning of quantum dots of different types and compositions in the air, and has the advantages of high resolution, strong universality, and suitability for large-scale industrial production.

[0006] In order to achieve the above object, the present invention provides a method for patterning a quantum dot thin film, which comprises the following steps:

[0007] (1) mixing quantum dots with a photosensitive crosslinker to form a thin layer; (2) performing a patterned exposure process on the thin layer to obtain a patterned quantum dot film; wherein the surface of the quantum dots has a ligand containing a carbon-hydrogen bond; and the photosensitive crosslinker has a structure shown in Formula I:

[0008]

[0009] In formula I, R1 is an electron-donating group; n≥2; and X is a group that does not affect the formation of a singlet intermediate.

[0010] In Formula I, the photosensitive crosslinker loses N2 molecules under UV light, forming a carbene intermediate containing an electrically neutral divalent carbon atom. During the exposure process, the singlet intermediate undergoes an insertion reaction with the carbon-hydrogen bonds in the ligands on the quantum dot surface, resulting in crosslinking between the quantum dots. X can be any functional group that does not affect the formation of the intermediate. R1 is a group that stabilizes the singlet carbene intermediate in air. R1 is designed to be an electron-donating group (i.e., a group that exhibits a negative electric field; an electron-donating group is a group that increases the electron cloud density on the benzene ring when a substituent replaces a hydrogen on the benzene ring). The introduction of R1 serves to inhibit the conversion of the carbene intermediate from the singlet to the triplet state, thereby improving the singlet intermediate's stability to oxygen in air and ensuring sufficient crosslinking of the ligands during the exposure process.

[0011] According to a specific embodiment of the present invention, preferably, in Formula I, R1 contains one or more structures selected from the group consisting of alkylamino, alkoxy, ether, acyloxy, amide, alkyl, alkylene, carboxymethyl, and phenyl; n is 2, 3, or 4; and X is selected from the group consisting of H, halogen, hydroxy, alkyl and its derivatives, alkoxy and its derivatives, amino, and nitrile.

[0012] According to a specific embodiment of the present invention, preferably, X is selected from -Cl, -F, -OH, -H, -CH3, -CF3, -OCH3, -NH2 or -CN, preferably -CF3, which is beneficial to improve the reaction activity.

[0013] According to a specific embodiment of the present invention, preferably, R1 contains one or more structures selected from the group consisting of phenyl, ether, and alkylene; n is 2, 3, or 4; and X is selected from -CF3.

[0014] According to a specific embodiment of the present invention, preferably, the photosensitive crosslinker has 1-100 carbon atoms and a molecular weight of 100-10000; considering molecular safety and ease of synthesis, the molecular weight is more preferably 500-2000.

[0015] According to a specific embodiment of the present invention, preferably, the photosensitive crosslinking agent is selected from

[0016]

[0017] (1,3,5-tris((2-(3-(3-(trifluoromethyl)-3H-diazirin-3-yl)phenoxy)ethoxy)methyl)benzene, photosensitive crosslinker A),

[0018]

[0019] (3-(trifluoromethyl)-3-(3-(2-((4-((2-(4-(3-(trifluoromethyl))-3H-diazirin-3-yl)phenoxy)ethoxy)methyl)benzyl)oxy)ethoxy)phenyl)-3H-diazirine, photosensitive cross-linking agent B),

[0020]

[0021] (bis(4-(3-(trifluoromethyl)-3H-diazirin-3-yl)phenoxy)octane, photosensitive crosslinker C),

[0022]

[0023] (1,2,4,5-tetrakis((2-(3-(3-(trifluoromethyl)-3H-diazirin-3-yl)phenoxy)ethoxy)methyl)benzene, photosensitive crosslinker D) or a combination of two or more thereof.

[0024] According to a specific embodiment of the present invention, preferably, the material of the quantum dots (the material of single-component quantum dots, the material of the core or shell of core-shell quantum dots) includes one or a combination of two or more of Group II-VI compounds, Group III-V compounds, Group IV-VI compounds, Group I-III-VI compounds, and perovskite nanocrystals.

[0025] According to a specific embodiment of the present invention, preferably, the quantum dots are core-shell structured quantum dots.

[0026] According to a specific embodiment of the present invention, preferably, the II-VI group compound includes CdSe, CdS, CdTe, Cd x Se 1-x S, Cd x Se 1-x Te, ZnO, ZnSe, ZnS, ZnTe, Zn x Se 1-x S, Zn x Se 1-x Te, Cd x Zn 1-x Se, Cd x Zn 1-x S, Cd x Zn 1-x Te, HgSe, HgS, HgTe, Hg x Cd 1-x Se, Hg x Cd 1-x S, Hg x Cd 1-x One or a combination of two or more of Te, wherein 0<x<1.

[0027] According to a specific embodiment of the present invention, preferably, the III-V compound includes one or a combination of two or more of InP, InAs, InSb, InN, GaP, GaAs, GaSb, GaN, AlP, AlAs, AlSb, and AlN.

[0028] According to a specific embodiment of the present invention, preferably, the IV-VI group compound includes PbS, PbSe, PbTe, Pb x Se 1-x S, Pb x Se 1-x Te, SnS, SnSe, SnTe, Sn x Se 1-x S, Sn x Se 1-x One or a combination of two or more of Te, wherein 0<x<1.

[0029] According to a specific embodiment of the present invention, preferably, the I-III-VI group compound includes one or a combination of two or more of CuInS2, CuInSe2, and AgInS2.

[0030] According to a specific embodiment of the present invention, preferably, the perovskite nanocrystals include one or a combination of two or more of CsPbY3, CH3NH3PbY3, FAPbY3, MAPbY3, wherein Y is selected from Cl, Br or I, and MA and FA represent methylammonium and formamide, respectively.

[0031] According to a specific embodiment of the present invention, preferably, the surface ligands of the quantum dots have 3-30 carbon atoms.

[0032] According to a specific embodiment of the present invention, preferably, the surface ligands of the quantum dots contain hydrocarbon chains.

[0033] According to a specific embodiment of the present invention, preferably, the main chain of the surface ligand of the quantum dot contains a carbon-hydrogen bond.

[0034] According to a specific embodiment of the present invention, preferably, the surface ligands of the quantum dots contain one or more structures selected from the group consisting of thiol, carboxylic acid, amine, phosphine, and phosphonic acid.

[0035] According to a specific embodiment of the present invention, preferably, the surface ligands of the quantum dots include one or a combination of two or more of oleylamine, oleic acid, octadecylamine, 1-dodecanethiol, trioctylphosphine, and octadecylphosphonic acid.

[0036] According to a specific embodiment of the present invention, preferably, in step (1), quantum dots and a photosensitive crosslinker are mixed in a solvent to obtain a solution, and the solution is formed into a thin layer; wherein the concentration of quantum dots in the solution is 5-1000 mg / ml, and the mass concentration ratio of quantum dots to the added photosensitive crosslinker is 1:(0.01-1).

[0037] According to a specific embodiment of the present invention, preferably, the solvent of the solution is selected from one or a combination of two or more of toluene, chlorobenzene, n-hexane, n-octane, n-heptane, cyclohexane, dichloromethane, chloroform and tetrahydrofuran.

[0038] According to a specific embodiment of the present invention, preferably, the molar absorption coefficient of the photosensitive crosslinking agent at the exposure treatment wavelength is 10 cm -1 M -1 to 10 6 cm -1 M -1 .

[0039] According to a specific embodiment of the present invention, preferably, each step of the quantum dot thin film patterning method is respectively implemented in air, nitrogen, argon or other inert gases.

[0040] According to a specific embodiment of the present invention, preferably, in step (2), the wavelength of the exposure treatment is 100-500 nm (more preferably 200-500 nm), and the light dose is 1-5000 mJ / cm 2 .

[0041] According to a specific embodiment of the present invention, preferably, after the thin layer is exposed, an elution solvent is used to remove the raw material that has not undergone cross-linking (remove the unexposed quantum dot area), and the elution solvent is a non-polar solvent (dielectric constant less than 10), more preferably including one or a combination of two or more of toluene, chlorobenzene, n-hexane, n-octane, n-heptane, cyclohexane, dichloromethane, chloroform, and tetrahydrofuran.

[0042] According to a specific embodiment of the present invention, the above method includes the following specific steps:

[0043] (1) forming a thin film layer in which quantum dots and a photosensitive crosslinker are uniformly dispersed on one side of the substrate;

[0044] (2) performing an exposure treatment on a specific area of ​​the quantum dot thin film layer, so that a ligand cross-linking reaction occurs in the exposed area;

[0045] (3) Then, the unexposed portion is removed by solvent washing to obtain a patterned quantum dot film.

[0046] The present invention also provides a patterned quantum dot film prepared by the above-mentioned quantum dot film patterning method.

[0047] The present invention also provides a photoelectric device, the structure of which comprises an anode, a cathode, and a quantum dot light-emitting layer, wherein the quantum dot light-emitting layer is the above-mentioned patterned quantum dot film or is produced by the above-mentioned quantum dot film patterning method.

[0048] According to a specific embodiment of the present invention, preferably, the quantum dot light-emitting layer is located between the cathode and the anode, and the materials of the anode and the cathode are independently selected from metals or carbon materials; the metal is selected from one or a combination of two or more of Al, Ag, Au, Cu, Mo, Mg, Ba, and Ca, and the carbon material is selected from one or a combination of two or more of carbon nanotubes, graphite, graphene, and carbon fibers.

[0049] According to a specific embodiment of the present invention, preferably, the structure of the optoelectronic device further comprises an electron injection layer, a hole injection layer, an electron transport layer, and a hole transport layer. The electron injection layer and the electron transport layer are located between the cathode and the quantum dot light-emitting layer, with the electron injection layer close to the cathode side and the electron transport layer close to the quantum dot light-emitting layer; the hole injection layer and the hole transport layer are located between the anode and the quantum dot light-emitting layer, with the hole injection layer close to the anode side and the hole transport layer close to the quantum dot light-emitting layer side.

[0050] According to a specific embodiment of the present invention, preferably, the material of the electron injection layer includes one or a combination of two or more of alkali metal halides, alkali metal organic complexes, organic phosphorus oxides, and organic thio (or seleno) phosphine compounds.

[0051] According to a specific embodiment of the present invention, preferably, the material of the electron transport layer includes a single metal oxide and / or a doped metal oxide, and the single metal oxide is selected from one or a combination of two or more of ZnO, ZrO2, SnO2, BaO, TiO2, and Ta2O3; the doped metal oxide is the above-mentioned single metal oxide doped with a certain proportion of one or more elements selected from Al, Li, Ga, Mg, Sn, In, F, Cl, etc.

[0052] According to a specific embodiment of the present invention, preferably, the material of the hole injection layer is selected from poly(3,4-ethylenedioxythiophene), poly(styrenesulfonic acid), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4'-tris(2-naphthylphenylamino)triphenylamine, 1,4,5,8,9,12-hexaazatriphenyl-2,3,6,7,10,11-hexanitrile, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, metal oxides such as NiO, MoO2, WO3, CrO3, CuO, and transition metal sulfur compounds such as MoS2, MoSe2, WS2, CuS, WS2, or a combination of two or more thereof.

[0053] According to a specific embodiment of the present invention, preferably, the material of the hole transport layer is selected from poly (3-hexylthiophene-2,5-diyl), poly (9-vinylcarbazole), poly [ [ (2,4-dimethylphenyl) imino] -1,4-phenylene (9,9-dioctyl-9H-fluorene-2,7-diyl) -1,4-phenylene], poly (9,9-dioctylfluorene-2,7-diyl), poly [bis (4-phenyl) (4-butylphenyl) amine], poly [ (9,9-dioctylfluorenyl -2,7-diyl) -co- (4,4 '- (N- (4-tert-butylphenyl) diphenylamine)], poly [9, 9-dioctylfluorene-bis-N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine], tris[4-(carbazol-9-yl)phenyl]amine, 4,4'-bis(9-carbazol)biphenyl, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, poly(3,4-ethylenedioxythiophene), poly(styrenesulfonic acid), graphene, NiO, WO3, CuI, CuSCN, CuO, CuInS2, GaN, C60, MoO3, V2O5, CrO3, or a combination of two or more thereof.

[0054] According to a specific embodiment of the present invention, preferably, the above-mentioned optoelectronic device is an array optoelectronic device.

[0055] The present invention provides a method for patterning quantum dots in air, through the chemical design of cross-linked molecules, without compromising the optoelectronic properties of the quantum dots. By introducing electron-donating groups into the carbene cross-linking molecules, the energy of the singlet carbene intermediate is significantly lower than that of the triplet state. In air, the singlet carbene does not convert to a triplet state to react with oxygen, and quantum dot thin film patterning can be achieved by cross-linking the quantum dot surface ligands. The present invention has the following beneficial effects:

[0056] 1. This method is not only feasible in inert gas atmospheres such as nitrogen and argon, but can also achieve efficient patterning of quantum dot materials of different types and compositions in air. The resulting pattern resolution can reach 2 microns, which is close to the limit resolution of the UV lithography machine used. It is simple and easy to operate and is suitable for low-cost, large-scale actual production and application.

[0057] 2. Under air conditions, the designed carbene singlet intermediate is stable, the cross-linking reaction is mild, and it does not damage the optical properties of different types of quantum dots;

[0058] 3. The method for constructing the light-emitting layer of the quantum dot light-emitting display device provided by the present invention can be applied to actual QLEDs (quantum dot light-emitting diodes), and exhibits a level comparable to that of ordinary thin-film devices in terms of luminous brightness and current density. It can maintain the electrical properties of the quantum dot material itself, and the efficient and stable patterning method in air has opened up an important path for the development of full-color light-emitting displays based on quantum dots. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 This is a diagram of the cross-linking mechanism between quantum dots and carbene cross-linkers;

[0060] Figure 2 Schematic diagram of the process for patterning quantum dot films;

[0061] Figure 3 These are optical photographs of cadmium-free quantum dot patterns with three different luminescent colors based on the photosensitive crosslinker A in Example 1, taken under a fluorescence microscope;

[0062] Figure 4 This is an optical photograph of a ZnSe / ZnS quantum dot pattern with different ligands based on photosensitive crosslinker A in Example 2 under a fluorescence microscope;

[0063] Figure 5 This is an optical photograph of an InP / ZnS quantum dot pattern based on the photosensitive crosslinker B in Example 3 under a fluorescence microscope;

[0064] Figure 6 This is an optical photograph of an InP / ZnS quantum dot pattern based on the photosensitive crosslinker C in Example 4 under a fluorescence microscope;

[0065] Figure 7 These are optical photographs of cadmium-based quantum dot patterns with three different luminescent colors based on the photosensitive crosslinker A in Example 5, taken under a fluorescence microscope;

[0066] Figure 8 In Example 6, a cadmium-based CdSe / Cd 1-x Zn x Optical photograph of Se / ZnSe quantum dot pattern under fluorescence microscope;

[0067] Figure 9 This is an optical photograph of the three quantum dot multicolor patterns in Example 7 under a fluorescence microscope;

[0068] Figure 10 The molar absorption coefficient diagram of three photosensitive crosslinkers A, B, and C;

[0069] Figure 11 The graph shows the change of fluorescence quantum yield of two different color lnP / ZnS quantum dot films before and after patterning;

[0070] Figure 12 This is a graph showing the fluorescence lifetime change of a lnP / ZnS quantum dot film before and after patterning;

[0071] Figure 13 It is a cadmium-based CdSe / Cd 1-x Zn x Changes in fluorescence quantum yield of Se / ZnSe quantum dot film before and after patterning;

[0072] Figure 14 Figures of constructed cadmium-based and InP-based QLEDs devices, where A is a diagram showing the specific structures of cadmium-based and InP-based QLEDs, B is a photograph of the electroluminescent pattern of cadmium-based QLEDs, C is a diagram showing the relationship between current density and luminous brightness and voltage of cadmium-based QLEDs, D is a diagram showing the emission wavelengths of cadmium-based QLEDs at different voltages and a diagram of unit pixels lit in actual QLED tests, E is a diagram showing the relationship between current density and luminous brightness and voltage of InP-based QLEDs, and F is a diagram showing the emission wavelengths of InP-based QLEDs at different voltages;

[0073] Figure 15 This is a graph showing the change in fluorescence quantum yield of a lnP / ZnS quantum dot film before and after patterning;

[0074] Figure 16 This is a graph showing the fluorescence lifetime change of a lnP / ZnS quantum dot film before and after patterning;

[0075] Figure 17 This is a photo of the effect of lnP / ZnS quantum dot patterning under a fluorescence microscope;

[0076] Figure 18 This is a photo of the effect of lnP / ZnS quantum dot patterning under a fluorescence microscope. DETAILED DESCRIPTION

[0077] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0078] Preparation Example 1

[0079] This preparation example provides a photosensitive crosslinker molecule A, the synthesis method of which is as follows (refer to patent PCT / CA2022 / 050293):

[0080] Under an argon atmosphere, NaH (60% dispersion in mineral oil, 632 mg) was added to anhydrous tetrahydrofuran (10 mL). A solution of 2-(4-(3-(trifluoromethyl)-3H-diacridin-3-yl)phenoxy)ethan-1-ol (3.26 g) in anhydrous tetrahydrofuran (5 mL) was added dropwise at 0°C, and the reaction was stirred for 10 minutes. A solution of 1,3,5-tris(bromomethyl)benzene (1.52 g) in anhydrous tetrahydrofuran (10 mL) was then added dropwise at 0°C, and the reaction was stirred at room temperature overnight. The colored mixture was filtered, washed with dichloromethane solution, and purified by silica gel column chromatography using hexane and dichloromethane as eluents to obtain photosensitive crosslinker A as a yellow oil.

[0081] Preparation Example 2

[0082] This preparation example provides a photosensitive crosslinker molecule B, the synthesis method of which is as follows (refer to patent PCT / CA2022 / 050293):

[0083] Under an argon atmosphere, NaH (60% dispersion in mineral oil, 1.68 g) was added to anhydrous tetrahydrofuran (30 mL). A solution of 2-(4-(3-(trifluoromethyl)-3H-diacridin-3-yl)phenoxy)ethane-1-ol (8.28 g) in anhydrous tetrahydrofuran (15 mL) was added dropwise at 0°C, and the reaction was stirred for 10 minutes. 1,4-Bis(bromomethyl)benzene (4.44 g) in anhydrous tetrahydrofuran (20 mL) was then added dropwise at 0°C, and the reaction was stirred at room temperature overnight. The colored mixture was filtered and washed with dichloromethane. It was further purified by silica gel column chromatography using pentane and diethyl ether as eluents to obtain photosensitive crosslinker B.

[0084] Preparation Example 3

[0085] This preparation example provides a photosensitive crosslinker molecule C, the synthesis method of which is as follows (refer to the literature "Stefania F. Musolino, et al. Structure-function relationships in aryl diazirines reveal optimal design features to maximize C-H insertion, Chem. Sci., 2021, 12, 12138-12148"):

[0086] Triethylamine (6.8 mL) and elemental iodine (4.52 g) were added sequentially to a dichloromethane solution (41 mL) of 1,8-bis(4-(3-(trifluoromethyl)diazetidin-3-yl)phenoxy)octane (4.2 g) at 0°C. The colored mixture was stirred at 0°C for 1 hour, diluted with dichloromethane solution, and washed with saturated aqueous sodium thiosulfate solution. After extraction with dichloromethane solution three times, the organic extract was washed with brine, dried over magnesium sulfate, filtered, and concentrated. The product was purified by silica gel column chromatography using pentane and diethyl ether as eluents to obtain a light yellow solid photosensitive crosslinker C.

[0087] Preparation Example 4

[0088] This preparation example provides a photosensitive crosslinker molecule D, the synthesis method of which is as follows (refer to patent PCT / CA2022 / 050293):

[0089] Under an argon atmosphere, NaH (60% dispersion in mineral oil, 632 mg) was added to anhydrous tetrahydrofuran (30 mL). A solution of 2-(4-(3-(trifluoromethyl)-3H-diacridin-3-yl)phenoxy)ethan-1-ol (3.26 g) in anhydrous tetrahydrofuran (15 mL) was added dropwise at 0°C, and the reaction was stirred for 10 minutes. A solution of 1,2,4,5-tetrakis(bromomethyl)benzene in anhydrous tetrahydrofuran (20 mL) was then added dropwise at 0°C, and the reaction was stirred at room temperature overnight. The colored mixture was filtered, washed, and purified by silica gel column chromatography to obtain photosensitive crosslinker D as a yellow oil.

[0090] Example 1

[0091] This embodiment provides a quantum dot patterning method based on a photosensitive crosslinker molecule A and three patterned films of cadmium-free quantum dots; wherein the quantum dots used for patterning include red and green lnP (core) / ZnS (shell) quantum dots, and the surface ligands are mainly oleic acid. Reference for the synthesis of red and green quantum dots (Bing Chen, et al. InP Quantum Dots: Synthesis and Lighting Applications, Small, 2020, 16, 2002454); including ZnSe (core) / ZnS (shell) blue quantum dots, the surface ligands are mainly oleylamine and oleic acid, and the blue quantum dot synthesis reference (Min Gao, et al. Bulk-like ZnSe Quantum Dots Enabling Efficient Ultra-narrow Blue Light-Emitting Diodes, Nano Lett., 2021, 21, 7252-7260). The specific implementation steps are as follows:

[0092] (1) In an air atmosphere, a silicon wafer was used as a substrate and ultrasonically cleaned for 15 minutes using organic solvents such as toluene, acetone, methanol, and isopropanol. A solution of quantum dots of a certain color and a photosensitive crosslinker A was spin-coated on one side of the silicon wafer at a speed of 1500 rpm. The solvent was toluene. For red quantum dots, the concentration of the InP / ZnS red quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker A was 1 mg / mL. For green quantum dots, the concentration of the InP / ZnS green quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker A was 2 mg / mL. For blue quantum dots, the concentration of the ZnSe / ZnS blue quantum dots in the solution was 20 mg / mL, and the concentration of the photosensitive crosslinker A was 1 mg / mL.

[0093] (2) Selectively expose a quantum dot film of one color using a mask. The exposure light source is 365 nm and the light dose is 50 mJ / cm 2 , the illumination time is 5s, the photosensitive crosslinker A in the exposed part crosslinks with the oleylamine or oleic acid ligand on the surface of the quantum dots, changing the solubility of the quantum dots in toluene, which is different from the unexposed part;

[0094] (3) The quantum dot film is immersed in toluene, and the unexposed quantum dots fall off the silicon wafer, while the selectively exposed parts show a pattern.

[0095] The crosslinking mechanism between quantum dots and carbene crosslinkers in the quantum dot patterning method of the present invention is as follows: Figure 1 As shown, the process of quantum dot film patterning is as follows Figure 2 shown.

[0096] The optical microscope photos of the red, green and blue patterns prepared in this embodiment are shown in FIG. Figure 3 As shown, Figure 3 Middle A is a red quantum dot circular array pattern with a diameter of 30 microns; Figure 3 Middle B is an "animal dog" pattern formed by green quantum dots; Figure 3 The middle C is the "Tsinghua University emblem" pattern formed by blue quantum dots, demonstrating the ability of this method to construct complex patterns.

[0097] Example 2

[0098] This example provides a quantum dot patterning method based on photosensitive crosslinker A and a patterned film of quantum dots with different ligands. The quantum dots used in this example are ZnSe / ZnS blue quantum dots, whose surface ligand is primarily 1-dodecanethiol. The preparation method of quantum dots is based on the literature Jeehye Yang, et al. Nondestructive Photopatterning of Heavy-Metal-Free Quantum Dots, Adv. Mater., 2022, 34, 2205504.

[0099] Compared with the preparation method of the blue ZnSe / ZnS quantum dot patterned film in Example 1, the difference between this embodiment and Example 1 is that the surface ligands oleylamine and oleic acid of the ZnSe / ZnS blue quantum dots are replaced with 1-dodecanethiol to obtain Figure 4 A blue quantum dot array with a linewidth of 2 microns is shown.

[0100] Example 3

[0101] This example provides a quantum dot patterning method and a patterned quantum dot film based on a photosensitive crosslinker B. The InP / ZnS red quantum dots used are the same as those in Example 1, and the surface ligands are oleylamine or oleic acid. The specific implementation steps are as follows:

[0102] (1) In air, a commercial silicon wafer was used as a substrate and ultrasonically cleaned for 15 minutes using organic solvents such as toluene, acetone, methanol, and isopropanol. A solution of red InP / ZnS quantum dots and photosensitive crosslinker B was spin-coated on one side of the silicon wafer at a speed of 1500 rpm. The solvent was toluene, and the concentration of the InP / ZnS red quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker B was 2 mg / mL.

[0103] (2) The red quantum dot film was selectively exposed using a mask in an air atmosphere with an exposure light source of 365 nm and a light dose of 200 mJ / cm 2 , the illumination time is 20s, the photosensitive crosslinker B in the exposed part cross-links with the ligands on the surface of the quantum dots, changing the solubility of the red quantum dots in toluene, which is different from the unexposed part;

[0104] (3) The quantum dot film is immersed in toluene, and the unexposed part of the quantum dots falls off from the silicon wafer, and the selectively exposed part shows the following Figure 5 The red quantum dot diamond array pattern shown has a diamond side length of 50 microns.

[0105] Example 4

[0106] This embodiment provides a quantum dot patterning method and a quantum dot patterned film based on a photosensitive crosslinker C. The same InP / ZnS red quantum dots as in Example 1 are used. The specific implementation steps are as follows:

[0107] (1) In air, a commercial silicon wafer was used as a substrate and ultrasonically cleaned for 15 minutes using organic solvents such as toluene, acetone, methanol, and isopropanol. A solution of red InP / ZnS quantum dots and photosensitive crosslinker C was spin-coated on one side of the silicon wafer at a speed of 1500 rpm. The solvent was toluene, and the concentration of the InP / ZnS red quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker C was 2 mg / mL.

[0108] (2) The red quantum dot film was selectively exposed using a mask in an air atmosphere with an exposure light source of 365 nm and a light dose of 300 mJ / cm 2 , the illumination time is 30s, the photosensitive crosslinker C in the exposed part cross-links with the ligands on the surface of the quantum dots, changing the solubility of the red quantum dots in toluene, which is different from the unexposed part;

[0109] (3) The quantum dot film is immersed in toluene, and the unexposed part of the quantum dots falls off from the silicon wafer, and the selectively exposed part shows the following Figure 6 The red quantum dot square array pattern shown has a side length of 60 microns.

[0110] Example 5

[0111] This embodiment provides a quantum dot patterning method based on photosensitive crosslinker A and patterned films of three cadmium-based quantum dots. Cadmium-based red quantum dots CdSe / CdS are selected, and the surface ligand is oleylamine. The preparation method is based on the literature (Chaodan Pu, et al. Electrochemically-stable ligands bridge the photoluminescence-electroluminescence gap of quantum dots. Nat. Commun., 2020, 11(1):937). Cadmium-based green quantum dots CdSe / CdS are selected. 1-x Zn x Se 1-y S y / ZnS, the surface ligand is oleic acid, the preparation method of the quantum dots is referenced in the literature (Himchan Cho, et al. Direct Optical Patterning of Quantum Dot Light-Emitting Diodes via In Situ Ligand Exchange. Adv. Mater., 2020, 32, 2003805), and the cadmium-based blue quantum dots Cd 1-x Zn x S / ZnS, the surface ligand is oleic acid. The preparation method of quantum dots is based on the literature (Wan Ki Bae, et al. Gram-Scale One-Pot Synthesis of Highly Luminescent Blue Emitting Cd 1-x Zn x S / ZnS Nanocrystals. Chem. Mater., 2008, 20, 5307–5313). The specific implementation steps are as follows:

[0112] (1) In air, a commercial silicon wafer was used as a substrate and ultrasonically cleaned for 15 minutes using organic solvents such as toluene, acetone, methanol, and isopropanol. A solution of cadmium-based quantum dots and photosensitive crosslinker A was spin-coated on one side of the silicon wafer at a speed of 1500 rpm. The solvent was toluene. For red quantum dots, the concentration of CdSe / CdS red quantum dots in the solution was 30 mg / mL, and the concentration of photosensitive crosslinker A was 1 mg / mL. For green quantum dots, the concentration of CdSe / CdS red quantum dots in the solution was 10 mg / mL. 1-x Zn x Se 1-y S y The concentration of ZnS quantum dots was 30 mg / mL, and the concentration of photosensitive crosslinker A was 2 mg / mL. For blue quantum dots, the concentration of Cd 1-x Zn x The concentration of S / ZnS blue quantum dots was 20 mg / mL, and the concentration of photosensitive crosslinker A was 1 mg / mL;

[0113] (2) The cadmium-based quantum dot film was selectively exposed using a mask in an air atmosphere with an exposure light source of 365 nm and a light dose of 50 mJ / cm 2 , the illumination time is 5s, the photosensitive crosslinker A in the exposed part cross-links with the ligands on the surface of the quantum dots, changing the solubility of the quantum dots in toluene, which is different from the unexposed part;

[0114] (3) The quantum dot film is immersed in toluene, and the unexposed part of the quantum dots falls off from the silicon wafer, and the selectively exposed part shows the following Figure 7 The pattern shown. Figure 7 A to C in the figure are red, green, and blue patterns respectively;

[0115] Example 6

[0116] This embodiment provides a quantum dot patterning method based on photosensitive crosslinkers B and C and a patterned film of cadmium-based quantum dots. 1-x Zn x Se / ZnSe red quantum dots, the ligand is mainly oleic acid, the quantum dot preparation method refers to the literature "Chaoyu Xiang, et al. High efficiency and stability of ink-jet printed quantum dot light emitting diodes. Nat Commun., 2020, 11(1): 1646", the specific patterning implementation steps are the same as in Example 5, and the patterning effect diagram is shown in FIG. Figure 8 As shown, Figure 8 A is a red quantum dot array with a line width of 50 microns obtained based on photosensitive crosslinker B. During the implementation process, the concentration of quantum dots in the solution was 30 mg / mL, the concentration of photosensitive crosslinker B was 1 mg / mL, and the light dose was 200 mJ / cm 2 , Figure 8 Figure B shows a red quantum dot array with a line width of 10 microns obtained based on photosensitive crosslinker C. During the implementation process, the concentration of quantum dots in the solution was 30 mg / mL, the concentration of photosensitive crosslinker C was 1 mg / mL, and the light dose was 300 mJ / cm 2 .

[0117] Example 7

[0118] This example provides a quantum dot patterning method based on photosensitive crosslinker A and a multi-color patterned film of three-color quantum dots. The red, green, and blue quantum dots used are the same as those in Example 1. The specific implementation steps are as follows:

[0119] (1) In air, a commercial silicon wafer was used as a substrate and ultrasonically cleaned for 15 minutes using organic solvents such as toluene, acetone, methanol, and isopropanol. A solution of red InP / ZnS quantum dots and photosensitive crosslinker A was spin-coated on one side of the silicon wafer at a speed of 1500 rpm. The solvent was toluene, and the concentration of the InP / ZnS red quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker A was 1 mg / mL.

[0120] (3) The red quantum dot film was selectively exposed using a mask. The exposure light source was 365 nm and the light dose was 100 mJ / cm 2 , illumination time 10s;

[0121] (3) Soaking the quantum dot film in toluene causes the unexposed quantum dots to fall off the silicon wafer, while the selectively exposed portions become visible, resulting in a red array pattern that is no longer soluble in toluene.

[0122] (4) On the substrate showing the red pattern, a solution of green InP / ZnS quantum dots and photosensitive crosslinker A was spin-coated at 1500 rpm. The solvent was toluene. The concentration of InP / ZnS green quantum dots in the solution was 30 mg / mL, and the concentration of photosensitive crosslinker A was 2 mg / mL.

[0123] (5) Selectively expose the green quantum dot film using a mask. The exposure light source is 365 nm and the light dose is 100 mJ / cm 2 , illumination time 10s;

[0124] (6) Soaking the quantum dot film in toluene, the unexposed quantum dots fall off the silicon wafer, and the selectively exposed green parts appear;

[0125] (7) On the substrate showing the red and green array patterns, a solution of blue ZnSe / ZnS quantum dots and photosensitive crosslinker A was spin-coated at 1000 rpm. The solvent was toluene. The concentration of the ZnSe / ZnS blue quantum dots in the solution was 40 mg / mL, and the concentration of the photosensitive crosslinker A was 2 mg / mL.

[0126] (8) The blue quantum dot film was selectively exposed using a mask. The exposure light source was 365 nm and the light dose was 100 mJ / cm 2 , illumination time 10s;

[0127] (9) The above quantum dot film is immersed in toluene, and the unexposed blue quantum dots fall off the silicon wafer, and the selectively exposed blue part appears, parallel to the previously cross-linked red and green array patterns, as shown in FIG. Figure 9 As shown, the size of a single array is 10 microns by 50 microns.

[0128] Test Example 1 Determination of the molar absorption coefficient of photosensitive cross-linked molecules

[0129] This test example provides the molar absorption coefficient curves of three photosensitive crosslinkers A, B, and C, such as Figure 10 As shown, the three photosensitive crosslinkers were configured with approximately 6×10 -4mol / L solution, the solvent is toluene, and the corresponding ultraviolet absorbance A is tested using a Cary 5000 UV-Vis-NIR spectrometer. The molar absorptivity K is calculated using the Lambert-Beer law A=Kbc, where c is the concentration of the photosensitive crosslinker in mol / L and b is the thickness of the absorption layer (1 cm). Referring to this method, the molar absorptivity of the three photosensitive crosslinkers in the ultraviolet band is obtained in turn, and the absorption capacity of the three photosensitive crosslinkers in the ultraviolet band is quantified.

[0130] Test Example 2: Comparison of Fluorescence Quantum Yield Before and After Quantum Dot Patterning

[0131] This test example compares the fluorescence quantum yields of cadmium-free red and green quantum dots before and after patterning. The samples were prepared in air, using the same InP / ZnS red and InP / ZnS green quantum dots as in Example 1. The specific implementation steps are as follows:

[0132] (1) A red quantum dot solution was spin-coated at 1500 rpm on a 2 cm × 2 cm quartz wafer. The solvent was toluene. The concentration of the lnP / ZnS red quantum dots in the solution was 30 mg / mL. The fluorescence quantum yield of the film without patterning was measured using a Horiba FluoroMax Plus spectrometer.

[0133] (2) A solution of red quantum dots and photosensitive crosslinker A was spin-coated on a 2 cm × 2 cm quartz sheet at 1500 rpm. The solvent was toluene. The concentration of the lnP / ZnS red quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker A was 1 mg / mL. The fluorescence quantum yield of the film was measured using a Horiba FluoroMax Plus spectrometer.

[0134] (3) The film prepared according to the method of step (2) was subjected to ultraviolet exposure with a wavelength of 365 nm and a dose of 200 mJ / cm 2 , the illumination time is 20s, and the fluorescence quantum yield of the film after the exposure step is measured using a Horiba FluoroMax Plus spectrometer;

[0135] (4) The exposed film was immersed in toluene solvent for elution, the film surface was blown dry with nitrogen, and the fluorescence quantum yield of the film after the elution step was measured using a Horiba FluoroMax Plus spectrometer;

[0136] Similarly, for green lnP / ZnS quantum dots, the luminescence quantum yield of the film after each patterning step was tested. The concentration of green quantum dots in the spin-coating solution was 30 mg / mL, the concentration of photosensitive crosslinker A was 2 mg / mL, the wavelength of light was 365 nm, and the light dose was 200 mJ / cm2 , illumination time 20s.

[0137] The results are as follows Figure 11 As shown, both red and green lnP / ZnS quantum dots can maintain good fluorescence quantum yield. The quantum yield of the initial film without treatment of quantum dots is normalized to 100%. After patterning in air, both red and green lnP / ZnS quantum dots have a fluorescence quantum yield of 90%.

[0138] Test Example 3: Changes in Fluorescence Lifetime Before and After Quantum Dot Patterning

[0139] This test example examined the change in fluorescence lifetime before and after quantum dot patterning. The sample was prepared in air, using the InP / ZnS red quantum dots from Example 1. The specific implementation steps are as follows:

[0140] (1) A 2 cm × 2 cm quartz wafer was used as the substrate and spin-coated with a lnP / ZnS red quantum dot solution at 1500 rpm. The solvent was toluene and the concentration of the lnP / ZnS red quantum dots in the solution was 30 mg / mL. The average fluorescence lifetime of the film without patterning was measured using a Horiba FluoroMaxPlus with time-correlated single photon counting (TCSPC) system.

[0141] (2) A 2 cm × 2 cm quartz sheet was spin-coated at 1500 rpm with a solution of red quantum dots and photosensitive crosslinker A. The solvent was toluene. The concentration of the lnP / ZnS red quantum dots in the solution was 30 mg / mL, and the concentration of the photosensitive crosslinker A was 1 mg / mL. The average fluorescence lifetime of the film was measured using a Horiba FluoroMax Plus with time-correlated single photon counting (TCSPC) system.

[0142] (3) The film obtained in step (2) was subjected to ultraviolet exposure with a wavelength of 365 nm and a dose of 200 mJ / cm 2 The illumination time was 20 s, and the average fluorescence lifetime of the film after the exposure step was measured using the Horiba FluoroMax Plus with time-correlated single photoncounting (TCSPC) system;

[0143] (4) The exposed film was immersed in toluene solvent for elution, and the film surface was blown dry with nitrogen. The average fluorescence lifetime of the film after the elution step was measured using the Horiba FluoroMax Plus with time-correlated single photon counting (TCSPC) system;

[0144] The results are as follows Figure 12 As shown, the red lnP / ZnS quantum dots can maintain a good average fluorescence lifetime after patterning. The average fluorescence lifetime of the initial film without quantum dots is 31.12ns. After mixing to form a quantum dot and photosensitive crosslinker film, the average fluorescence lifetime is 31.00ns. After UV exposure, the average fluorescence lifetime of the film is 28.98ns. After elution, the average fluorescence lifetime of the film is 30.59ns.

[0145] Test Example 4 Comparison of Fluorescence Quantum Yield Before and After Cadmium-Based Quantum Dot Patterning

[0146] This test example compares the fluorescence quantum yield of a cadmium-based quantum dot before and after patterning. The results are as follows: Figure 13 As shown, the quantum dots are selected from the red CdSe / Cd 1-x Zn x Se / ZnSe quantum dots, the specific implementation steps are the same as those of the red InP / ZnS quantum dots in Test Example 2. After patterning in air, the red CdSe / Cd 1-x Zn x The Se / ZnSe QDs have 80% fluorescence yield retention compared to the initial film.

[0147] Test Example 5: Construction of Patterned Cadmium-Based QLEDs Light-Emitting Display Device and Evaluation of Corresponding Electrical Performance

[0148] This test example provides a patterned cadmium-based QLEDs light-emitting display device and the corresponding electrical performance evaluation, using the CdSe / Cd 1-x Zn xSe / ZnSe red quantum dots, light-emitting display devices refer to the ITO / poly(3,4-ethylenedioxythiophene)polystyrene sulfonate(PEDOT:PSS) / Poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt(4,4'-(N-(4-butylphenyl)))](TFB) / Q Ds / ZnO / Al structure provided in the literature ChaoyuXiang, et al. High efficiency and stability of ink-jet printed quantum dotlight emitting diodes. Nat Commun., 2020, 11(1): 1646, such as Figure 14 As shown in A. The specific implementation steps are as follows:

[0149] (1) Take a clean ITO substrate, ultrasonically clean it with commercial glass alkaline detergent for 15 minutes, then ultrasonically clean it with deionized water for 15 minutes, repeat twice, then ultrasonically clean it with anhydrous ethanol for 15 minutes, and blow dry it with nitrogen for later use;

[0150] (2) The cleaned ITO substrate was surface treated with plasma for 6 min; then fixed on a spin coater, spin-coated with PEDOT:PSS solution at 4000 rpm for 40 s, and annealed at 150°C for 15 min;

[0151] (3) Spin-coat the prepared TFB solution on the substrate at 2000 rpm for 40 seconds and heat-anneal at 150°C for 10 minutes;

[0152] (4) Continue to construct the quantum dot layer (QDs) on the above substrate, prepare a mixed solution of red quantum dots and photosensitive crosslinker A, the solvent is chlorobenzene, and the CdSe / Cd 1-x Zn x The concentration of Se / ZnSe red quantum dots was 10 mg / mL, and the concentration of photosensitive crosslinker A was 1 mg / mL. The film was spin-coated at 2000 rpm for 60 s. After that, the film was selectively irradiated with 365 nm ultraviolet light using a mask at a dose of 300 mJ / cm 2, so that the ligands on the surface of the quantum dots are fully cross-linked, and the areas where no cross-linking reaction occurs are dynamically eluted using chlorobenzene solvent (50-100μL chlorobenzene is dripped on the top of the wafer at a speed of 2000rpm) to obtain a patterned film, which is heated and annealed at 80°C for 10 minutes; when conducting electrical performance test evaluation, the difference in the construction of the light-emitting layer is that no mask is used, and the entire film is subjected to light treatment to avoid the influence of excessive leakage current, thereby better reflecting the impact of this cross-linking patterning method on the optoelectronic performance of the device.

[0153] (5) ZnO ethanol solution was spin-coated at 2000 rpm for 40 s and annealed at 80 °C for 20 min;

[0154] (6) Place the above device in a high vacuum evaporation chamber (pressure ≤ 1×10 -6 mbar), thermally deposited 80nm metal Al electrode;

[0155] (7) Use the power supply to connect the positive and negative poles of the device to light up the actual QLEDs pattern, such as Figure 14 The rectangular array shown in B has dimensions of 10 μm × 50 μm.

[0156] (8) The electrical performance of the device was evaluated. The device was encapsulated with UV-curable resin and the device parameters and performance such as brightness, current density and emission wavelength of QLEDs were tested using a combination of QE-PRO spectrometer and Keithley 2400 in an air atmosphere. Figure 14 Figure C shows the current density and luminance vs. voltage curves of the constructed patterned red QLEDs device; the current density is approximately 700 mA / cm 2 , luminous brightness reaches 12000cd / m 2 ; Figure 14 D in the middle is the emission wavelength of the patterned QLEDs at different voltages of 2, 3, 4, and 5V, all at 620nm. The actual test illuminates the square pixels of the QLEDs (see Figure 14 The area is 7.25mm 2 .

[0157] Test Example 6: Construction of InP-based QLEDs light-emitting display devices and evaluation of their electrical properties

[0158] This test example provides a construction and corresponding electrical performance evaluation of a patterned InP-based QLEDs light-emitting display device. The InP / ZnS red quantum dots in Example 1 were used. The light-emitting display device structure was the same as that in Test Example 5, with an ITO / PEDOT:PSS / TFB / QDs / ZnO / Al structure. The specific implementation steps are as follows:

[0159] (1) Take a clean ITO substrate, ultrasonically clean it with commercial glass alkaline detergent for 15 minutes, then ultrasonically clean it with deionized water for 15 minutes, repeat twice, then ultrasonically clean it with anhydrous ethanol for 15 minutes, and blow dry it with nitrogen for later use;

[0160] (2) The cleaned ITO substrate was surface treated with plasma for 20 min; then fixed on a spin coater, spin-coated with PEDOT:PSS solution at 3000 rpm for 30 s, and annealed at 150°C for 15 min;

[0161] (3) Spin-coat the prepared TFB solution on the substrate at 3000 rpm for 40 seconds and heat-anneal at 150°C for 10 minutes;

[0162] (4) A quantum dot layer (QDs) was constructed on the above substrate. A mixed solution of red quantum dots and photosensitive crosslinker A was prepared. The solvent was octane. The concentration of red quantum dots in the solution was 20 mg / mL and the concentration of photosensitive crosslinker A was 1 mg / mL. The solution was spin-coated at a speed of 2000 rpm for 60 s. The entire film was cross-linked by 365 nm ultraviolet light with a light dose of 100 mJ / cm 2 , dynamic elution was performed using octane solvent and annealing was performed at 80 °C for 10 min;

[0163] (5) ZnO ethanol solution was spin-coated at 2000 rpm for 40 s and annealed at 80 °C for 20 min;

[0164] (6) Place the above device in a high vacuum evaporation chamber (pressure ≤ 1×10 -6 mbar), thermally deposited 100nm metal Al electrode;

[0165] (7) The electrical performance of the device was evaluated. The device was encapsulated with UV-curable resin and the device parameters and performance such as brightness, current density and emission wavelength of QLEDs were tested using a combination of QE-PRO spectrometer and Keithley 2400 in an air atmosphere. Figure 14 E in the middle is the current density and luminous brightness vs. voltage curve of the constructed patterned red InP-based QLEDs device; the current density is about 600mA / cm 2 , luminous brightness reaches 35000cd / m 2 ; Figure 14 F in the middle is the emission wavelength of the patterned QLEDs at different voltages of 2, 3, 4, and 5 V, all at 620 nm.

[0166] Test Example 7: Changes in Fluorescence Quantum Yield Before and After Patterning

[0167] This test example investigated the change in fluorescence quantum yield of a quantum dot before and after patterning under the action of a photosensitive crosslinker. Compared with Test Example 2, the photosensitive crosslinker A was changed to C, the patterning conditions were changed to a concentration of 30 mg / mL of InP / ZnS red quantum dots in the solution, a concentration of 2 mg / mL of photosensitive crosslinker C, and an illumination dose of 300 mJ / cm 2 , illumination time 30s, the results are as follows Figure 15 As shown, the quantum yield of the initial film without quantum dots treatment is normalized to 100%, and after patterning with photosensitive crosslinker C in air, the red lnP / ZnS quantum dots have a good yield retention of 80%.

[0168] Test Example 8: Changes in Fluorescence Lifetime Before and After Patterning

[0169] This test example investigates the change in fluorescence lifetime of a quantum dot before and after patterning under the action of a photosensitive crosslinker. Compared with Test Example 3, the photosensitive crosslinker A was changed to C, the patterning conditions were changed to a concentration of 30 mg / mL of InP / ZnS red quantum dots in the solution, a concentration of 2 mg / mL of photosensitive crosslinker C, and an illumination dose of 300 mJ / cm 2 , illumination time 30s, the results are as follows Figure 16 As shown, the patterning step does not reduce the average fluorescence lifetime of the quantum dots themselves. The average fluorescence lifetime of the initial film without quantum dots is 31.12ns, and the average fluorescence lifetime of the final patterned film is 28.83ns.

[0170] Comparative Example 1

[0171] This comparative example provides a method for preparing a patterned quantum dot film. Compared with the quantum dot patterning methods in Examples 1, 3, and 4, this comparative example differs in that the photosensitive crosslinker is replaced by 3,3'-(4,4'-perfluorobutane-1,4-diyl)bis(4,1-phenylene)bis(3-trifluoromethyl)-3H-diacridine instead of the provided A, B, and C. The molecular formula is as follows:

[0172]

[0173] The molecular synthesis method refers to the existing literature "Shaoyong Lu, et al. Beyond a Linker: The Role of Photochemistry of Crosslinkers in the Direct Optical Patterning of Colloidal Nanocrystals. Angew. Chem. Int. Ed., 2022, 61, e202202633", and its preparation method includes the following steps:

[0174] At 0°C under argon, a triethylamine solution (3.06 mL) was added dropwise to a dichloromethane solution (21 mL) of 3,3'-((perfluorobutane-1,4-diyl)bis(4,1-phenylene))bis(3-(trifluoromethyl)diaziridine) (2.1 g) over 10 minutes. Elemental iodine (2.04 g) was added to the resulting mixture in three portions and stirred at 0°C for 2 hours. The reaction mixture was diluted with dichloromethane (60 mL) and transferred to a separatory funnel. The organic layer was washed with water, saturated sodium thiosulfate solution, water, and brine, and dried over sodium sulfate. The organic layer was purified by silica gel column chromatography to obtain the desired bright white crystalline cross-linked molecule.

[0175] The same process was carried out in air. In this comparative example, a portion of the exposed InP / ZnS quantum dot film was immersed in toluene, but no pattern was observed (e.g. Figure 17 The reason is that: after ultraviolet light exposure, the 3,3'-(4,4'-perfluorobutane-1,4-diyl)bis(4,1-phenylene)bis(3-trifluoromethyl)-3H-diacridine molecule generates a singlet carbene intermediate. In the air, the singlet carbene is easily converted to a triplet state and reacts with oxygen, consuming the generated intermediate, and failing to undergo cross-linking through the quantum dot surface ligand. However, the A, B, and C molecules designed in the present invention inhibit the process of the intermediate singlet state to the triplet state due to the introduction of electron-donating groups. Even in the air, the singlet intermediate and the surface ligand can be efficiently cross-linked, thereby realizing the patterning of the quantum dot material.

[0176] Comparative Example 2

[0177] This comparative example provides a patterning effect of quantum dots under the action of different photosensitive crosslinkers. Compared with the quantum dot patterning conditions in Example 4, photosensitive crosslinker C is used in air. The difference is that the ultraviolet light dose is changed from 300mJ / cm 2 Replaced with 50mJ / cm 2 , the partially exposed red lnP / ZnS quantum dot film was immersed in toluene, but no pattern was seen (e.g. Figure 18 As shown), compared with the photosensitive crosslinker A in Example 1 at 50mJ / cm 2 The reason for the patterning is that the molar absorption coefficient of photosensitive crosslinker A is large at a wavelength of 365 nm, and it has a higher ultraviolet light utilization rate. The tridentate crosslinking sites in photosensitive crosslinker A also make the crosslinking reaction more efficient.

Claims

1. A method for patterning a quantum dot thin film, comprising the following steps: (1) Mixing quantum dots with a photosensitive crosslinker to form a thin layer; (2) performing patterned exposure processing on the thin layer to obtain a patterned quantum dot thin film; Wherein, the surface of the quantum dots has ligands containing carbon-hydrogen bonds; The photosensitive crosslinking agent has the structure shown in Formula I: Formula I, Wherein, in formula I, R1 contains one or more structures selected from phenyl, ether, and alkylene; n is 2, 3, or 4; X is selected from -CF3; The photosensitive crosslinking agent has 1-100 carbon atoms and a molecular weight of 100-10,000.

2. The method for patterning a quantum dot thin film according to claim 1, wherein: The photosensitive crosslinking agent is selected from 、 、 、 One or a combination of two or more.

3. The method for patterning a quantum dot thin film according to claim 1, wherein: The material of the quantum dots includes one or a combination of two or more of II-VI group compounds, III-V group compounds, IV-VI group compounds, I-III-VI group compounds, and perovskite nanocrystals.

4. The method for patterning a quantum dot thin film according to claim 1, wherein: The quantum dots are core-shell quantum dots.

5. The method for patterning a quantum dot thin film according to claim 3, wherein: The II-VI compounds include CdSe, CdS, CdTe, Cd x Se 1-x S, Cd x Se 1-x Te, ZnO, ZnSe, ZnS, ZnTe, Zn x Se 1-x S, Zn x Se 1-x Te, Cd x Zn 1-x Se, Cd x Zn 1-x S, Cd x Zn 1-x Te, HgSe, HgS, HgTe, Hg x Cd 1-x Se, Hg x Cd 1-x S, Hg x Cd 1-x One or a combination of two or more of Te, wherein 0<x<1.

6. The method for patterning a quantum dot thin film according to claim 3, wherein: The III-V group compound includes one or a combination of two or more of InP, InAs, InSb, InN, GaP, GaAs, GaSb, GaN, AlP, AlAs, AlSb, and AlN.

7. The method for patterning a quantum dot thin film according to claim 3, wherein: The IV-VI group compounds include PbS, PbSe, PbTe, Pb x Se 1-x S, Pb x Se 1-x Te, SnS, SnSe, SnTe, Sn x Se 1-x S, Sn x Se 1-x One or a combination of two or more of Te, wherein 0<x<1.

8. The method for patterning a quantum dot thin film according to claim 3, wherein: The I-III-VI group compound includes one or a combination of two or more of CuInS2, CuInSe2, and AgInS2.

9. The method for patterning a quantum dot thin film according to claim 3, wherein: The perovskite nanocrystals include one or a combination of two or more of CsPbY3, CH3NH3PbY3, FAPbY3, and MAPbY3, wherein Y is selected from Cl, Br, or I.

10. The method for patterning a quantum dot thin film according to claim 1, wherein: The number of carbon atoms of the surface ligands of the quantum dots is 3-30.

11. The method for patterning a quantum dot thin film according to claim 1, wherein: The main chain of the surface ligand of the quantum dot contains a carbon-hydrogen bond.

12. The method for patterning a quantum dot thin film according to claim 1, wherein: The surface ligands of the quantum dots contain one or more structures of thiol, carboxylic acid, amine, phosphine and phosphonic acid.

13. The method for patterning a quantum dot thin film according to claim 1, wherein: The surface ligands of the quantum dots include one or a combination of two or more of oleylamine, oleic acid, octadecylamine, 1-dodecanethiol, trioctylphosphine, and octadecylphosphonic acid.

14. The method for patterning a quantum dot thin film according to claim 1, wherein: In step (1), quantum dots and a photosensitive crosslinker are mixed in a solvent to obtain a solution, and the solution is formed into a thin layer; wherein the concentration of quantum dots in the solution is 5-1000 mg / ml, and the mass concentration ratio of quantum dots to the added photosensitive crosslinker is 1:(0.01-1).

15. The method for patterning a quantum dot thin film according to claim 14, wherein: The solvent of the solution is selected from one or a combination of two or more of toluene, chlorobenzene, n-hexane, n-octane, n-heptane, cyclohexane, dichloromethane, chloroform and tetrahydrofuran.

16. The method for patterning a quantum dot thin film according to claim 1, wherein: The molar absorption coefficient of the photosensitive crosslinker at the exposure wavelength is 10 cm -1 M -1 to 10 6 cm -1 M -1 .

17. The method for patterning a quantum dot thin film according to claim 1, wherein: Each step of the quantum dot thin film patterning method is performed in air, nitrogen or argon respectively.

18. The method for patterning a quantum dot thin film according to claim 1, wherein: In step (2), the wavelength of the exposure treatment is 100-500 nm, and the light dose is 1-5000 mJ / cm 2 .

19. The method for patterning a quantum dot thin film according to claim 1, wherein: After the thin layer is exposed, an elution solvent is used to remove the raw materials that have not undergone cross-linking. The elution solvent is a non-polar solvent.

20. The method for patterning a quantum dot thin film according to claim 19, wherein: The elution solvent includes one or a combination of two or more of toluene, chlorobenzene, n-hexane, n-octane, n-heptane, cyclohexane, dichloromethane, chloroform, and tetrahydrofuran.

21. A patterned quantum dot film produced by the quantum dot film patterning method according to any one of claims 1 to 20.

22. A photoelectric device, comprising an anode, a cathode, and a quantum dot light-emitting layer, wherein: The quantum dot light-emitting layer is the patterned quantum dot film according to claim 21 or is prepared by the quantum dot film patterning method according to any one of claims 1 to 19.

23. The optoelectronic device according to claim 22, wherein The quantum dot light-emitting layer is located between the cathode and the anode, and the materials of the anode and the cathode are independently selected from metals or carbon materials; the metal is selected from one or a combination of two or more of Al, Ag, Au, Cu, Mo, Mg, Ba, and Ca, and the carbon material is selected from one or a combination of two or more of carbon nanotubes, graphite, graphene, and carbon fibers.

24. The optoelectronic device according to claim 23, wherein The structure of the photoelectric device also includes an electron injection layer, a hole injection layer, an electron transport layer, and a hole transport layer. The electron injection layer and the electron transport layer are located between the cathode and the quantum dot light-emitting layer, with the electron injection layer close to the cathode and the electron transport layer close to the quantum dot light-emitting layer; the hole injection layer and the hole transport layer are located between the anode and the quantum dot light-emitting layer, with the hole injection layer close to the anode and the hole transport layer close to the quantum dot light-emitting layer.

25. The optoelectronic device according to claim 24, wherein The material of the electron injection layer includes one or a combination of two or more of alkali metal halides, alkali metal organic complexes, organic phosphorus oxides, organic thiophosphine compounds, and organic selenophosphine compounds.

26. The optoelectronic device according to claim 24, wherein The material of the electron transport layer includes a single metal oxide and / or a doped metal oxide, wherein the single metal oxide is selected from one or a combination of two or more of ZnO, ZrO2, SnO2, BaO, TiO2, and Ta2O3; the doped metal oxide is the single metal oxide doped with one or more elements of Al, Li, Ga, Mg, Sn, In, F, and Cl.

27. The optoelectronic device according to claim 24, wherein The material of the hole injection layer is selected from one or more of poly(3,4-ethylenedioxythiophene), poly(styrenesulfonic acid), 4,4',4'-tris(N-3-methylphenyl-N-phenylamino)triphenylamine, 4,4',4'-tris(2-naphthylphenylamino)triphenylamine, 1,4,5,8,9,12-hexaazatriphenyl-2,3,6,7,10,11-hexanitrile, 2,3,5,6-tetrafluoro-7,7',8,8'-tetracyanodimethyl-p-benzoquinone, NiO, MoO2, WO3, CrO3, CuO, MoS2, MoSe2, WS2, CuS, and WS2.

28. The optoelectronic device according to claim 24, wherein The material of the hole transport layer is selected from poly (3-hexylthiophene-2,5-diyl), poly (9-vinylcarbazole), poly [ [ (2,4-dimethylphenyl) imino] -1,4-phenylene (9,9-dioctyl-9H-fluorene-2,7-diyl) -1,4-phenylene], poly (9,9-dioctylfluorene-2,7-diyl), poly [bis (4-phenyl) (4-butylphenyl) amine], poly [ (9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4'- (N- (4-tert-butylphenyl) diphenylamine)], poly [9,9-dioctylfluorene- ...9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4'- (N- (4-tert-butylphenyl) diphenylamine)], poly [9,9-dioctylfluorene-bis (4-phenyl) (4-butylphenyl) amine], poly [9,9-dioctylfluorenyl-2,7-diyl) -co- (4,4'- (N- (4-tert-butylphenyl) diphenylamine)], poly [9,9-dioctylfluorenyl-bis (4-phenyl) (4-butylphenyl) amine], poly [9,9-dioctylfluorenyl- -N,N-(4-butylphenyl)-bis-N,N-phenyl-1,4-phenylenediamine], tris[4-(carbazol-9-yl)phenyl]amine, 4,4'-bis(9-carbazol)biphenyl, N,N'-diphenyl-N,N'-bis(3-methylphenyl)-1,1'-biphenyl-4,4'-diamine, poly(3,4-ethylenedioxythiophene), poly(styrenesulfonic acid), graphene, NiO, WO3, CuI, CuSCN, CuO, CuInS2, GaN, C60, MoO3, V2O5, CrO3, or a combination of two or more thereof.

29. The optoelectronic device according to claim 22 or 24, wherein The photoelectric device is an array photoelectric device.

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