Photosensitive composite material for laser-assisted MicroLED mass transfer and preparation method and application thereof

Abstract

The invention provides a photosensitive composite material for laser-assisted MicroLED mass transfer. The photosensitive composite material comprises a random copolymer as shown in a formula (I) and photosensitive small molecules. The novel transfer composite material is prepared by mixing a polymer and azosulfone micromolecules in proportion. The mechanical property and thermal property of the polymer part can be adjusted by simply adjusting the types of comonomers, so that the polymer part has high adhesive force and can be spin-coated into a smooth thin film, and an overall network framework of a film layer is provided. Azo sulfone micromolecules serve as a photosensitive component, performance adjustment is achieved by adjusting the types of side chain groups on aniline raw materials, and the azo sulfone micromolecules have high-selectivity absorption on lasers with different wavelengths and are decomposed to generate a large amount of gas to generate pushing force so that core particles can be transferred. Through optimization of synthesis steps, the yield of polymers and small molecules is improved, and subsequent complex purification steps are not needed. The yield of more than 99% can be achieved in the core particle picking step, and complete release of a small area can be achieved in the core particle release step.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a photosensitive composite material for laser-assisted MicroLED mass transfer, and a preparation method and application thereof. Background Art

[0002] Micro LED is a highly promising next-generation display technology. Mass transfer is the key to its mass production. It is a process of transferring millions to hundreds of millions of core particles from the epitaxial substrate to the light-emitting substrate. Industrial production has very high requirements for transfer yield, transfer accuracy, and transfer rate. The current mainstream mass transfer technologies include fluid self-loading transfer, roller transfer, PDMS stamp transfer, and laser-assisted mass transfer. Among them, laser-assisted mass transfer is a transfer solution that is more suitable for large-screen display production. Laser-assisted transfer can be divided into laser irradiation interface ablation decomposition, laser irradiation interface bubbling, and laser-induced interface stress assistance. The most critical material needed in these transfer solutions is the dynamic release layer. It is coated on a temporary substrate and needs to realize the two processes of core particle pickup and core particle release. First, it must pick up the core particles peeled off from the source substrate through its own adhesion. Then, under the action of the laser, the dynamic release layer undergoes certain changes, and the adhesion is reduced while generating a driving force. The core particles will break away from the adhesion control and complete the final release. The selection of dynamic release layer material is very important for achieving high yield, accuracy and speed in the entire pick-up and release process.

[0003] Common dynamic release layer materials include metal film, polyimide, and triazine polymers. Among them, metal film belongs to the type of direct decomposition by laser ablation. The release mechanism is that under a certain wavelength and power of laser, the metal film will be completely ablated and decomposed into metal fragments (Appl.Surf.Sci 186 (2002) 221-226), and the fragments generate driving force to transfer the core particles. However, it will also cause serious debris pollution.

[0004] Polyimide materials are bubbling types formed by laser irradiation interface (ACS Appl. Mater. 12 (2020) 54230-54240). The mechanism of action is that laser irradiation causes the shallow layer of glue to decompose or melt, generating gas to form bubbles, the change in interface curvature leads to reduced adhesion, and an instantaneous impact is generated to provide transfer kinetic energy, releasing the core particles. However, this type of bubbling material has a high decomposition temperature and requires a high ablation threshold.

[0005] Therefore, it is very necessary to provide a dynamic release layer material with high transfer yield. Summary of the invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a photosensitive composite material for laser-assisted MicroLED mass transfer, and the above-mentioned composite material provided by the present invention has a high transfer yield.

[0007] The present invention proposes a composite material of a random copolymer and a photosensitive small molecule (azosulfone, tryptophan, etc.) suitable for laser-assisted mass transfer of Micro LEDs. The mechanical and thermal properties of the random copolymer are adjusted by adjusting the type of polymerized monomers, so that the entire material has film-forming properties and can be spin-coated into a smooth and flat film on a substrate. At the same time, it has high adhesion to complete the pickup of Micro LEDs during the transfer process. For example, when synthesizing azosulfone small molecules from aniline and sodium methanesulfinate, by adjusting the side chain groups on aniline, it can be made to have high selective absorption of lasers of different wavelengths used in the transfer process and decompose to generate volatile gases. And through a suitable synthesis route, the yield of random copolymers and azosulfone small molecules can be increased, and the purification process can be simplified.

[0008] The present invention provides a photosensitive composite material for laser-assisted MicroLED mass transfer, comprising: a random copolymer represented by formula (I) and a photosensitive small molecule;

[0009]

[0010] The composite material of the present invention comprises a random copolymer represented by formula (I).

[0011] Wherein, a=0.001-1, specifically 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 1; or a range between any two of the above;

[0012] b=0.001-1, specifically 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 1; or a range between any two of the above;

[0013] c = 0.001-1; specifically, it can be 0.01, 0.05, 0.1, 0.2, 0.5, 0.8, 1; or a range between any two of the above;

[0014] The above ratio is the molar ratio of the monomers. Specifically, a:b:c is (0.001-1):(0.001-1):(0.001-1); preferably, the molar ratio of a:b:c is (0.01-1):(0.01-1):(0.01-1);

[0015] The present invention 1 , R 2 and R 3Independently selected from alkyl, hydrogen, cyano, halogen, hydroxyl, amino, aromatic, epoxy, carbonyl, nitro, sulfonic acid, sulfonyl, borane substituted or unsubstituted C1-C50 alkyl, substituted or unsubstituted C1-C50 amide, substituted or unsubstituted C1-C50 ester, substituted or unsubstituted C1-C50 heteroaryl, substituted or unsubstituted C1-C50 aryloxy, substituted or unsubstituted C1-C50 heterocycloalkyl. The heteroatoms in the heteroaryl and heterocycloalkyl are from one or more of O, S, and N.

[0016] According to the present invention, the random copolymer shown in formula (I) is obtained by reacting two or more monomers containing carbon-carbon double bonds, including the following specific monomer structures: styrene, N-phenylacrylamide, N-phenylmethacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, methacrylate-2-ethylhexyl, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, isophorone diamine, naphthalene diisocyanate, acrylamide and methyl methacrylate, etc. The random copolymer can be obtained by free radical addition. In addition to free radical polymerization, it can also be a polymer formed by polymerization of other monomers in different ways.

[0017] The monomer structure is as follows:

[0018]

[0019] The random copolymer of the present invention is prepared by random copolymerization of one or more monomers mentioned above through free radical addition. 1 , R 2 , R 3 The groups are derived from the side chains of monomers after free radical addition.

[0020] In some specific embodiments, it can be prepared from styrene, N-phenylacrylamide, and N-phenylmethacrylamide; wherein the molar ratio of styrene, N-phenylacrylamide, and N-phenylmethacrylamide is 5:4:1;

[0021] In some specific embodiments, it can be prepared from styrene, N-phenylacrylamide, and ethylene oxide-2-methyl methacrylate; wherein the molar ratio of styrene, N-phenylacrylamide, and ethylene oxide-2-methyl methacrylate is 5:4:1;

[0022] In some specific embodiments, it can be prepared from butyl acrylate, N-isopropylacrylamide, styrene, ethylene oxide-2-methyl methacrylate, 2-ethylhexyl methacrylate, and 2-(perfluorohexyl)ethyl methacrylate; wherein the molar ratio of butyl acrylate, N-isopropylacrylamide, styrene, ethylene oxide-2-methyl methacrylate, 2-ethylhexyl methacrylate, and 2-(perfluorohexyl)ethyl methacrylate is 15:15:10:5:3:2;

[0023] In some specific embodiments, it can be prepared from butyl acrylate, N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, and 2-(perfluorobutyl)ethyl methacrylate; wherein the molar ratio of butyl acrylate, N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, and 2-(perfluorobutyl)ethyl methacrylate is 1:1:2:1;

[0024] In some specific embodiments, it can be prepared from butyl acrylate, N-isopropyl acrylamide, N-hydroxyethyl acrylamide, and dimethylaminoethyl methacrylate; wherein the molar ratio of butyl acrylate, N-isopropyl acrylamide, N-hydroxyethyl acrylamide, and dimethylaminoethyl methacrylate is 2:6:1:1;

[0025] In some specific embodiments, it can be prepared from isophorone diamine and naphthalene diisocyanate; wherein the molar ratio of isophorone diamine to naphthalene diisocyanate is 1:1.

[0026] In some specific embodiments, butyl acrylate, ethylene oxide-2-methyl methacrylate, acrylamide, and methyl methacrylate are prepared; wherein the molar ratio of butyl acrylate, ethylene oxide-2-methyl methacrylate, acrylamide, and methyl methacrylate is 10:1:4:5.

[0027] The random copolymer represented by formula (I) of the present invention has a weight average molecular weight of 0.5 to 1,000,000.

[0028] The photosensitive composite material provided by the present invention comprises photosensitive small molecules.

[0029] According to the present invention, the photosensitive small molecule comprises azosulfone or tryptophan of the structure of formula (II);

[0030]

[0031] Wherein R is a benzene ring in which the 2-6 positions are substituted by hydrogen, C1-C20 alkyl, C1-C20 alkynyl, C1-C20 alkenyl, halogen, C1-C20 alkoxy, aryloxy, aryl, heterocycloalkyl, heteroaryl, heteroaryloxy, cyano, carboxyl, carbonyl, nitro, hydroxyl, amino, sulfonic acid, sulfonyl, phosphate, phosphoryl, silicon, borane, etc. wherein the heteroatom in heteroaryl, heteroaryloxy, heterocycloalkyl is one or more of S, O, and N, and the halogen is one or more of Cl, F, I, and Br.

[0032] In some specific embodiments, the random copolymer represented by formula (I) has the following structure:

[0033] In some implementations of the present invention, the azosulfone represented by formula (II) is

[0034]

[0035]

[0036] In some specific implementation schemes of the present invention, the azosulfone represented by formula (II) has the following structure:

[0037]

[0038] According to the present invention, the mixing ratio of the polymer and the photosensitive small molecule is 500:1 to 1:500 (dry weight ratio).

[0039] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:500.

[0040] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:100.

[0041] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:50.

[0042] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:30.

[0043] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 1:1 to 1:10.

[0044] In some specific embodiments, the polymer and the photosensitive small molecule are mixed in a ratio of 1:1 to 1:3.

[0045] In some specific embodiments, the mixing ratio of the polymer and the photosensitive small molecule is 3:1.

[0046] The present invention provides a method for preparing a photosensitive composite material for laser-assisted MicroLED mass transfer, comprising the following steps:

[0047] A) mixing a polymer and a solvent to obtain a polymer solution; mixing a photosensitive small molecule and a solvent to obtain a photosensitive small molecule solution;

[0048] B) Mix the polymer solution and the photosensitive small molecule solution to obtain.

[0049] The method for preparing a photosensitive composite material for laser-assisted MicroLED mass transfer provided by the present invention first prepares a polymer.

[0050] The random copolymer of the present invention is obtained by reacting two or more monomers containing carbon-carbon double bonds. The polymer of the present invention is obtained by reacting two or more of styrene, N-phenylacrylamide, N-phenylmethacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, methacrylate-2-ethylhexyl, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, isophorone diamine, naphthalene diisocyanate, acrylamide and methyl methacrylate.

[0051] The monomer and the initiator are mixed, dioxane is added, dissolved, stirred in the presence of an inert gas, heated in an oil bath, reacted, precipitated in petroleum ether after the reaction is completed, and dried to obtain a polymer product. The temperature reflected by the oil bath is 70°C; the time is 24 hours. The present invention precipitates the generated product in petroleum ether, because petroleum ether as an organic solvent is miscible with dioxane, and the polymer has poor solubility in petroleum ether, and is easily precipitated in petroleum ether, and some unreacted monomer reactants can be dissolved in petroleum ether and removed.

[0052] The initiator azobisisobutyronitrile of the invention decomposes to generate isobutyronitrile groups, which initiate free radical reactions, and multiple monomers containing carbon-carbon double bonds undergo double bond addition and random copolymerization to generate polymers.

[0053] The present invention introduces inert gas to remove water and oxygen, thereby avoiding side reactions caused by the presence of oxygen and moisture.

[0054] In one specific embodiment of the present invention,

[0055] Add 50mmol styrene, 40mmol N-phenylacrylamide, and 10mmol N-phenylmethylacrylamide to the flask in sequence, and then weigh 0.1mmol of the initiator azobisisobutyronitrile and add it directly to the flask. Add 60ml of dioxane and stir to mix, and completely dissolve the above reactants. Add a rubber stopper to the mouth of the bottle and wrap the bottle mouth with wire for several turns to reinforce it. Insert a short needle on one side of the top of the rubber stopper to connect the bottle with the atmosphere. Insert a long needle on one side to ensure that the needle is below the liquid level, and pass argon from the long needle. Stir and ventilate for 15min. After ventilation, take out the short needle first, and quickly apply vaseline to the pinhole to seal it. Then take out the long needle and seal the pinhole with vaseline. Heat in a 70℃ oil bath under stirring for 24h. After the reaction is completed, precipitate in petroleum ether to obtain the precipitated product, and dry in an oven to obtain a polymer product.

[0056] Then prepare a photosensitive small molecule; the preparation of the photosensitive small molecule of the present invention comprises:

[0057] S1) mixing hydrochloric acid, water and p-phenoxyaniline, cooling in an ice-water bath and stirring to obtain a first solution; wherein the ratio of hydrochloric acid, water and p-phenoxyaniline is 4.4 mL:8.8 mL:20 mmol; the addition of hydrochloric acid can maintain the reaction medium to be strongly acidic, and can also react with sodium nitrite added later to generate nitrous acid.

[0058] Sodium nitrite is dissolved in water, cooled in an ice-water bath and stirred to obtain a second solution; the cooling time is 10 minutes; the amount of sodium nitrite added needs to be accurate, and the dropwise addition speed cannot be too fast, so that the entire reaction process is not lacking in the participation of sodium nitrite, and a diazotization reaction occurs with aromatic amines in a strong acid environment to generate an azoamino compound.

[0059] Dissolve sodium methanesulfinate in an organic solvent, cool in ice water and stir to obtain a third solution;

[0060] The above steps need to be carried out at a low temperature in an ice water bath, because the diazotization reaction is very unstable, and a slightly higher temperature will cause side reactions and produce too many by-products.

[0061] S2) adding the second solution dropwise to the first solution to obtain a fourth solution after the addition is complete; the addition time is 15 min;

[0062] The third solution was added dropwise to the fourth solution to obtain a fifth solution; the adding time was 10 min.

[0063] The added sodium methanesulfinate will react with the diazonium salt generated previously, removing a portion of the hydrogen halide to form azosulfone small molecules.

[0064] S3) adding potassium carbonate solution dropwise to the fifth solution, adjusting the pH value to 9-10, stirring at room temperature for reaction, and extracting the organic phase with dichloromethane after the reaction, washing, drying, and distilling under reduced pressure to obtain the product.

[0065] The present invention adds a saturated potassium carbonate solution to adjust the solution from a strong acid environment to an alkaline environment because the reaction between sodium methanesulfinate and diazonium salt is difficult to proceed in an acidic environment and can only react smoothly in an alkaline environment. In addition, the process of adjusting the pH needs to be slow. Too fast a dripping speed will make the alkalinity of a local area of ​​the solution instantly too high, and the local reaction is too fast to cause the generation of by-products.

[0066] The desired organic phase product is obtained by liquid separation using dichloromethane and deionized water because the density difference between dichloromethane and deionized water is large enough and they are immiscible. During liquid separation, the organic phase is in the upper layer and the aqueous phase is in the lower layer. The organic solvents dichloromethane and dioxane can be distilled out at 33-35°C by vacuum distillation, and finally vacuum drying is performed to obtain the final product without solvent.

[0067] In one specific embodiment of the present invention, the preparation of the photosensitive small molecule of the present invention specifically includes:

[0068] 4.4ml hydrochloric acid, 8.8ml deionized water and 20mmol p-phenoxyaniline. Place the round-bottom flask in an ice-water bath, cool and stir for 10 minutes to obtain solution 1. Weigh 20mmol of sodium nitrite and dissolve it completely in deionized water, cool and stir in an ice-water bath to obtain solution 2. Weigh 80mmol of sodium p-phenoxysulfinate and dissolve it in an organic solvent, cool and stir in ice water to obtain solution 3. Use a dropper to take a small amount of solution 2 and slowly add it to solution 1, and keep the drop time at about 15min. After solution 2 is added, immediately use a dropper to add solution 3 drop by drop to solution 4 to obtain solution 5. Keep the drop time at about 10min. Weigh excess potassium carbonate and dissolve it in deionized water to obtain a saturated solution, cool and stir in an ice-water bath. Use a dropper to take a small amount of potassium carbonate solution and add it dropwise to solution 5, observe and record the color and state changes of the solution, and measure the pH value of the solution with pH test paper after each drop until the solution is alkaline and the pH value is about 9-10. The ice-water bath was then removed, and the solution 5 was stirred at room temperature for 2 hours. After the reaction was completed, dichloromethane was added to separate and extract the organic phase, which was then washed with deionized water for 2-3 minutes. An appropriate amount of anhydrous sodium sulfate was added to the separated organic phase, and the mixture was allowed to stand and dry, and the sodium sulfate was filtered out to obtain the dehydrated organic phase.

[0069] The organic phase was poured into a spherical bottle for vacuum distillation to remove the organic solvent, and then placed in a vacuum drying oven for drying to obtain the final product as an orange-red powder.

[0070] The polymer and the solvent are mixed to obtain a polymer solution; the photosensitive small molecule and the solvent are mixed to obtain a photosensitive small molecule solution; the solvent is dioxane.

[0071] The polymer solution and the photosensitive small molecule solution are mixed to obtain the product.

[0072] The mixing ratio of the polymer and the photosensitive small molecule of the present invention is 500:1 to 1:500 (dry weight ratio). The mass ratio of the two has been clearly described above and will not be repeated here.

[0073] The present invention provides a method for laser-assisted MicroLED mass transfer, using the composite material described in any one of the above technical solutions as a dynamic release layer.

[0074] The present invention also provides the use of the above composite material as a dynamic release layer in laser-assisted MicroLED mass transfer.

[0075] The above process verification of the present invention specifically includes:

[0076] The prepared solution is evenly spin-coated on the sapphire substrate to form a uniform and smooth adhesive layer. The first step of transfer is to peel the MicroLED core particles from the original substrate. The temporary substrate coated with the composite material adhesive layer can pick up the core particles intact because of its strong adhesion. In the second step of transfer, the laser acts on the adhesive layer. The small molecules absorb the 355nm wavelength laser, and the overall photolysis and thermal decomposition are completely ablated, generating volatile gases that generate driving force to release the MicroLED core particles.

[0077] When azosulfone small molecules absorb 355nm wavelength laser, a π→π* transition will occur, and further inter-gap crossing will occur, and they will be excited from the singlet state to the triplet state to generate aromatic cations, which will further decompose to generate volatile nitrogen gas.

[0078] This scheme focuses on the preparation of an ablative polymer-azosulfone small molecule composite material suitable for laser-assisted MicroLED mass transfer. A new transfer composite material is prepared by mixing polymers and azosulfone small molecules in proportion. The polymer part can achieve mechanical and thermal properties adjustment by simply adjusting the type of comonomer, so that it has high adhesion and can be spin-coated into a smooth film to provide an overall network skeleton of the film layer. As a photosensitive component, the azosulfone small molecule can adjust its performance by adjusting the type of side chain groups on the aniline raw material, so that it has high selective absorption of lasers of different wavelengths, decomposes to generate a large amount of gas to generate a driving force for the core particle transfer. By optimizing the synthesis steps, the yield of polymers and small molecules can be improved without the need for subsequent complex purification steps. At present, the core particle picking step can achieve a yield of more than 99%, and the core particle release step can completely release a small area.

[0079] The material prepared by the invention has high adhesion, good film-forming property (smooth and flat without air bubbles, pinholes), and high wavelength selective absorption (the absorbance at 355nm is 12 times that at 266nm).

[0080] The present invention optimizes the optical, mechanical and thermal properties of the overall material by adjusting the raw material types and structures of the synthetic polymer and the azosulfone small molecule. The synthesis steps are simple and do not require complex purification steps, which is convenient for meeting different process verification steps. The polymer component has high adhesion to complete the pickup of the core particles. The azosulfone small molecule has a fast photolysis rate to generate gas to promote the release of the core particles.

[0081] The evidence collection method of the present invention comprises:

[0082] Nanoindentation characterizes the hardness and elastic modulus of the material after film formation. Universal material testing machine characterizes the material adhesion. UV spectrophotometer characterizes the absorbance change, and laser peeling verifies the process yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] Figure 1 Schematic diagram of the role of the transfer adhesive containing the composite material of the present invention in the mass transfer of MicroLEDs;

[0084] Figure 2 A microscope photo of the MicroLED mass transfer and peeling effect provided in Example 1 of the present application;

[0085] Figure 3 A microscope photo of the MicroLED mass transfer release effect provided in Example 1 of the present application;

[0086] Figure 4 Molecular weight measurement of the random polymer provided in Example 1 of the present application;

[0087] Figure 5 This is the H NMR spectrum of the p-phenoxyazosulfone small molecule provided in Example 1 of the present application;

[0088] Figure 6 A schematic diagram of the hardness value of the adhesive layer of the composite material after film formation provided in Examples 1, 2, and 3 of the present application;

[0089] Figure 7 A schematic diagram of the elastic modulus value of the adhesive layer of the composite material after film formation provided in Examples 1, 2, and 3 of the present application;

[0090] Figure 8 This is the ultraviolet spectrum of the p-methoxyazosulfone small molecule in Example 2 of the present application, which has high wavelength selective absorption at different wavelengths;

[0091] Fig. 9 This is a photo showing that the composite material in Example 2 of the present application has good film-forming properties;

[0092] Fig.10 This is the ultraviolet absorption spectrum of the phenoxyazosulfone small molecule in Example 1 of the present application under different illumination times (365nm), indicating that the small molecule has the ability of rapid photolysis;.

[0093] Fig.11 The H NMR spectrum of the p-methoxyazosulfone small molecule provided in Examples 2 and 3 of the present application;

[0094] Fig.12 The H NMR spectrum of the trifluoromethylazosulfone small molecule provided in Example 5 of the present application;

[0095] Fig.13 This is the H NMR spectrum (1H) of the o-methoxyazosulfone small molecule provided in Example 5 of the present application;

[0096] Fig.14 This is the H NMR spectrum of the o-chloroazosulfone small molecule provided in Example 6 of the present application. DETAILED DESCRIPTION

[0097] The present invention provides a photosensitive composite material for laser-assisted MicroLED mass transfer, and a preparation method and application thereof. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It should be pointed out in particular that all similar substitutions and modifications are obvious to those skilled in the art, and they all fall within the scope of protection of the present invention. The methods and applications of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the methods and applications of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0098] It should be understood that the expression "one or more of..." includes each of the items recited after the expression individually and in various different combinations of two or more of the recited items, unless otherwise understood from the context and usage. The expression "and / or" in combination with three or more recited items should be understood to have the same meaning, unless otherwise understood from the context.

[0099] The use of the terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, for example not excluding other unrecited elements or steps, unless otherwise specifically stated or otherwise understood from the context.

[0100] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural.

[0101] In this application, "at least one" means one or more, "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0102] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the present invention remains operable. In addition, two or more steps or actions may be performed simultaneously.

[0103] The use of any and all examples or exemplary language, such as "for example" or "including", herein is intended only to better illustrate the invention and does not limit the scope of the invention unless otherwise claimed. No language in this specification should be construed as indicating that any non-claimed element is essential to the practice of the invention.

[0104] In addition, the numerical ranges and parameters used to define the present invention are approximate values, and the relevant values ​​in the specific embodiments have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual test methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, quantities, values ​​and percentages used in this disclosure are modified by "about". Here, "about" generally means that the actual value is within plus or minus 10%, 5%, 1% or 0.5% of a specific value or range.

[0105] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0106] Some cases are recorded in the embodiments and comparative examples of the present invention, wherein the embodiments show certain implementation modes of the present invention. However, this does not mean that the effects of the present invention can only be achieved in these cases.

[0107] In order to further illustrate the present invention, a photosensitive composite material for laser-assisted MicroLED mass transfer, a preparation method and an application thereof provided by the present invention are described in detail below in combination with embodiments.

[0108] Example 1

[0109]

[0110]

[0111] The synthesis steps of polymer-azosulfone small molecule composite material are as follows:

[0112] Step 1: First, polymer synthesis was performed. 50 mmol of styrene, 40 mmol of N-phenylacrylamide, and 10 mmol of N-phenylmethylacrylamide were added to the flask in sequence, and then 0.1 mmol of the initiator azobisisobutyronitrile was directly added to the flask.

[0113] Step 2: Add 60 ml of dioxane and stir to mix until the above reactants are completely dissolved.

[0114] Step 3: Add a rubber stopper to the bottle mouth and wrap the bottle mouth with wire several times to reinforce it.

[0115] Step 4: Insert a short needle on one side of the top of the rubber stopper to connect the bottle to the atmosphere. Insert a long needle on one side, making sure the needle is below the liquid surface, and introduce argon gas from the long needle. Stir and ventilate for 15 minutes.

[0116] Step 5: After ventilation, take out the short needle first, and quickly apply vaseline to the needle hole to seal it. Then take out the long needle and seal the needle hole with vaseline as well.

[0117] Step 6: Heat in an oil bath at 70°C with stirring and react for 24 hours.

[0118] Step 7: After the reaction is completed, the product is precipitated in petroleum ether to obtain a precipitated product, which is then dried in an oven to obtain a polymer product.

[0119] Step 8: Perform azosulfone small molecule synthesis again. Add 4.4 ml hydrochloric acid, 8.8 ml deionized water and 20 mmol p-phenoxyaniline into a round-bottom flask in sequence. Place the round-bottom flask in an ice-water bath to cool and stir for 10 minutes to obtain solution 1.

[0120] Step 9: Weigh 20 mmol of sodium nitrite and completely dissolve it in deionized water, cool it in an ice water bath and stir it to obtain solution 2.

[0121] Step 10: Weigh 80 mmol of sodium p-phenoxysulfinate and dissolve it in an organic solvent, cool it in ice water and stir it to obtain solution 3.

[0122] Step 11: Use a dropper to slowly add a small amount of solution 2 to solution 1. Keep the adding time at about 15 minutes.

[0123] Step 12: Immediately after adding solution 2, add solution 3 dropwise into solution 4 using a dropper to obtain solution 5. The addition time is maintained at about 10 minutes.

[0124] Step 13: Weigh excess potassium carbonate and dissolve it in deionized water to obtain a saturated solution, cool it in an ice water bath and stir it.

[0125] Step 14: Use a dropper to take a small amount of potassium carbonate solution and add it to solution 5. Observe and record the changes in the color and state of the solution. Use pH test paper to measure the pH value of the solution after each drop until the solution becomes alkaline and the pH value is around 9-10.

[0126] Step 15: The ice-water bath was then removed and the solution 5 was stirred at room temperature for 2 hours.

[0127] Step 16: After the reaction is completed, dichloromethane is added to separate the organic phase and extract it, and then the organic phase is washed with deionized water for 2-3 minutes.

[0128] Step 17: Add an appropriate amount of anhydrous sodium sulfate to the separated organic phase, let it stand to dry, and filter out the sodium sulfate to obtain the dehydrated organic phase.

[0129] Step 18: Pour the organic phase into a spherical bottle for vacuum distillation to remove the organic solvent, and then place it in a vacuum drying oven to dry to obtain the final product as an orange-red powder.

[0130] Step 19: Preparation of polymer-azosulfone small molecule composite material: Weigh a certain amount of the dried polymer product, add dioxane, and shake to mix to obtain a colloidal polymer solution with a concentration of 0.25 g to 0.5 g / ml.

[0131] Step 20: Weigh a certain amount of dry azosulfone small molecule powder, completely dissolve it with dioxane, and prepare a solution with a concentration of 1g / ml.

[0132] Step 21: Mix the colloidal polymer solution and the p-phenoxyazosulfone small molecule solution at a ratio of 3:1 (dry weight ratio) to obtain a final composite material product. Let stand for later use.

[0133] Step 22: Process verification. Spin the prepared solution evenly on the sapphire substrate to form a uniform and smooth adhesive layer. In the first transfer step, the MicroLED core particles are peeled off from the original substrate. The temporary substrate coated with the composite material adhesive layer can pick up the core particles intact because of its strong adhesion. In the second transfer step, the laser acts on the adhesive layer, and the small molecules absorb the 355nm wavelength laser. The overall photolysis and thermal decomposition are completely ablated, and the volatile gas is generated to generate a driving force to release the MicroLED core particles.

[0134] The results are as follows Figure 2 to Figure 4 As shown, Figure 2 This is a microscope photo of the peeling yield > 99% result; Figure 3 The photo of the release yield 100% result is shown; Figure 4 To obtain the spectrum of the polymer; it can be seen that the molecular weight of the obtained polymer is: Mn. = 73543Mw. = 149622Mp. = 96306PDI = 2.034489.

[0135] Figure 5 The prepared azosulfone small molecule has a hydrogen nuclear magnetic spectrum; 1H NMR (400MHz, CDCl3) δ7.95, 7.94, 7.93, 7.93, 7.46, 7.44, 7.43, 7.28, 7.28, 7.26, 7.25, 7.13, 7.11, 7.11, 7.09, 7.09, 7.07, 7.07, 3.19, 2.04, 1.59, 1.26.

[0136] Figure 6 This is the photolysis UV spectrum of the synthesized azosulfone small molecule.

[0137] Example 2

[0138]

[0139] Polymer-azosulfone small molecule composite materials:

[0140] Step 1: Polymer synthesis. Styrene, N-phenylacrylamide, ethylene oxide-2-methyl methacrylate and initiator azobisisobutyronitrile are mixed and dissolved in a ratio of 5:4:1 for copolymerization. In addition, the ratio of styrene and N-phenylacrylamide in the copolymer monomer can be adjusted for polymerization, ranging from 8:1 to 1:8. Or the same amount of N-phenylacrylamide can be completely replaced by styrene.

[0141] Step 2: Composite material. Dissolve the above polymer in dioxane to prepare a colloidal solution with a concentration of 0.5g / ml. Dissolve the p-methoxyazosulfone small molecule in dioxane to prepare a solution with a concentration of 1g / ml. Thoroughly mix the polymer solution and the p-methoxyazosulfone small molecule solution in a ratio of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coat the prepared film, and verify the process flow.

[0142] Fig.11 The prepared p-methoxyazosulfone small molecule has a hydrogen nuclear magnetic spectrum; 1H NMR (400MHz, CDCl3) δ7.96, 7.94, 7.05, 7.03, 3.94, 3.19.

[0143] Example 3

[0144]

[0145] Polymer-azosulfone small molecule composite materials:

[0146] Step 1: polymer synthesis. Butyl acrylate, N-isopropylacrylamide, styrene, ethylene oxide-2-methyl methacrylate, 2-ethylhexyl methacrylate, 2-(perfluorohexyl)ethyl methacrylate and initiator are mixed and copolymerized in a ratio of 15:15:10:5:3:2. In addition, the total feed amount is kept unchanged, and the ratio of the copolymer monomer butyl acrylate: N-isopropylacrylamide: styrene can also be adjusted, such as 5:15:20, 20:15:5, etc.

[0147] Step 2: Composite material. Dissolve the above polymer in dioxane to prepare a colloidal solution with a concentration of 0.5g / ml. Dissolve the p-methoxyazosulfone small molecule in dioxane to prepare a solution with a concentration of 1g / ml. Thoroughly mix the polymer solution and the p-methoxyazosulfone small molecule solution in a ratio of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coat the prepared film, and verify the process flow.

[0148] The above polymers and synthetic small molecules of different types were mixed in different proportions to prepare films for process flow verification.

[0149] Fig.11 The prepared p-methoxyazosulfone small molecule has a hydrogen nuclear magnetic spectrum; 1H NMR (400MHz, CDCl3) δ7.96, 7.94, 7.05, 7.03, 3.94, 3.19.

[0150] Example 4

[0151]

[0152] Polymer-azosulfone small molecule composite materials:

[0153] Step 1: polymer synthesis. Butyl acrylate, N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate in a ratio of 1:1:2:1, or N-isopropylacrylamide, ethylene oxide-2-methyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, trifluoroethyl acrylate in a ratio of 4:4:1:1 and an initiator are mixed and copolymerized.

[0154] Step 2: Composite material. Dissolve the above polymer in dioxane to prepare a colloidal solution with a concentration of 0.5g / ml. Dissolve the diphenylamine azosulfone small molecule in dioxane to prepare a solution with a concentration of 1g / ml. Thoroughly mix the polymer solution and diphenylamine azosulfone small molecule solution in the ratio of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, 1:4 (dry weight ratio), spin-coat the prepared film, and verify the process flow.

[0155] Example 5

[0156]

[0157] Polymer-azosulfone small molecule composite materials:

[0158] Step 1: polymer synthesis. Mix butyl acrylate, N-isopropyl acrylamide, N-hydroxyethyl acrylamide, dimethylaminoethyl methacrylate and copolymerize 3-4 of them in different proportions. For example, butyl acrylate: N-isopropyl acrylamide: N-hydroxyethyl acrylamide: dimethylaminoethyl methacrylate = 2:6:1:1, or butyl acrylate: N-hydroxyethyl acrylamide: dimethylaminoethyl methacrylate = 2:2:1, or N-isopropyl acrylamide: N-hydroxyethyl acrylamide: dimethylaminoethyl methacrylate = 8:1:1, etc.

[0159] Step 2: Composite material. Dissolve the above polymer in dioxane to prepare a colloidal solution with a concentration of 0.5g / ml. Dissolve the o-methoxyazosulfone small molecule and p-trifluoromethyl in dioxane to prepare a solution with a concentration of 1g / ml, and then mix the o-methoxyazosulfone small molecule and p-trifluoromethylazosulfone small molecule in a ratio of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, 1:4. Then fully mix the polymer solution and the mixed azosulfone small molecule solution in a ratio of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, 1:4 (dry weight ratio), spin coat the prepared film, and verify the process flow.

[0160] Fig.12 This is the H NMR spectrum of the prepared trifluoromethylazosulfone small molecule; 1 H NMR (400 MHz, CDCl 3 )δ8.07,8.05,7.87,7.85,3.26.

[0161] Fig.13 The prepared o-methoxyazosulfone small molecule H NMR spectrum; 1H NMR (400 MHz, CDCl3) δ7.66, 7.64, 7.57, 7.55, 7.53, 7.06, 7.04, 6.97, 6.96, 6.94, 3.93, 3.13.

[0162] Example 6

[0163]

[0164] Polymer-azosulfone small molecule composite materials:

[0165] Step 1: Polymer synthesis. Isophorone diamine and naphthalene diisocyanate are dissolved in dioxane, mixed quickly and heated at 100°C for 20 hours. The product is precipitated in petroleum ether and dried. Step 2: Composite material. The above polymer is dissolved in dioxane to prepare a colloidal solution with a concentration of 0.5g / ml. The o-chloroazosulfone small molecule is dissolved in dioxane to prepare a solution with a concentration of 1g / ml. The polymer solution and the o-chloroazosulfone small molecule solution are fully mixed in the ratio of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, 1:4 (dry weight ratio), spin-coated and prepared for process flow verification.

[0166] Fig.14 This is the NMR spectrum of the prepared o-chloroazosulfone small molecule; 1 H NMR (400 MHz, CDCl 3 )δ7.78,7.76,7.65,7.63,7.62,7.60,7.43,7.41,7.39,7.26,3.23.

[0167] Example 7

[0168]

[0169] Polymer-azosulfone small molecule composite materials:

[0170] Step 1: polymer synthesis. Mix butyl acrylate, ethylene oxide-2-methyl methacrylate, acrylamide, and methyl methacrylate in different proportions for copolymerization. For example, butyl acrylate: ethylene oxide-2-methyl methacrylate: acrylamide: methyl methacrylate = 10:1:4:5, butyl acrylate: ethylene oxide-2-methyl methacrylate: acrylamide = 5:1:4, etc.

[0171] Step 2: Composite material. Dissolve the above polymer in dioxane to prepare a colloidal solution with a concentration of 0.5g / ml. Dissolve the triazene small molecule synthesized by diazotization of 4,4-diaminodiphenyl ether and N-methylethanolamine in dioxane (the synthesis steps are the same as those of azosulfone small molecules) and prepare a solution with a concentration of 1g / ml. Thoroughly mix the polymer solution and the triazene small molecule solution in the ratios of 1:1, 2:1, 3:1, 4:1, 1:2, 1:3, and 1:4 (dry weight ratio), spin-coat the prepared film, and verify the process flow.

[0172] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A photosensitive composite material for laser-assisted MicroLED mass transfer, characterized in that: include: A random copolymer represented by formula (I) and a photosensitive small molecule; Wherein, a=0.001~1, b=0.001~1, c=0.001~1; R1, R2 and R3 are independently selected from alkyl, hydrogen, cyano, halogen, hydroxyl, amino, aromatic, epoxy, carbonyl, nitro, sulfonic acid, sulfonyl, borane, substituted or unsubstituted C1~C50 alkyl, substituted or unsubstituted C1~C50 amide, substituted or unsubstituted C1~C50 ester, substituted or unsubstituted C1~C50 heteroaryl, substituted or unsubstituted C1~C50 aryloxy, substituted or unsubstituted C1~C50 heterocycloalkyl.

2. The photosensitive composite material according to claim 1, characterized in that: The photosensitive small molecule includes azosulfone or tryptophan of formula (II); Wherein R is a benzene ring, wherein positions 2 to 6 are substituted by hydrogen, C1-C20 alkyl, C1-C20 alkynyl, C1-C20 alkenyl, halogen, C1-C20 alkoxy, aryloxy, aryl, heterocycloalkyl, heteroaryl, heteroaryloxy, cyano, carboxyl, carbonyl, nitro, hydroxyl, amino, sulfonic acid, sulfonyl, phosphate, phosphoryl, silicon, or borane, which are mono- or poly-substituted.

3. The photosensitive composite material according to claim 1, characterized in that: The random copolymer represented by the formula (I) includes the following specific structure:

4. The photosensitive composite material according to claim 1, characterized in that: The random copolymer represented by formula (I) is obtained by reacting two or more compounds containing carbon-carbon unsaturated double bonds; the compound containing carbon-carbon unsaturated double bonds is obtained by reacting two or more of styrene, N-phenylacrylamide, N-phenylmethacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, methacrylate-2-ethylhexyl, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, isophorone diamine, naphthalene diisocyanate, acrylamide and methyl methacrylate.

5. The photosensitive composite material according to claim 1, characterized in that: The azosulfone represented by formula (II) is 6. The photosensitive composite material according to claim 1, characterized in that: The azosulfone shown in the formula (II) has the following structure:

7. A method for preparing a photosensitive composite material for laser-assisted MicroLED mass transfer, comprising the following steps: A) mixing the random copolymer with a solvent to obtain a polymer solution; mixing the photosensitive small molecule with the solvent to obtain a photosensitive small molecule solution; B) Mix the polymer solution and the photosensitive small molecule solution to obtain.

8. The preparation method according to claim 7, characterized in that: The solvent is dioxane; The mixing ratio of the polymer and the photosensitive small molecule is 500:1 to 1:500 (dry weight ratio).

9. The preparation method according to claim 7, characterized in that: The preparation method of the random copolymer comprises: The invention is obtained by reacting two or more compounds containing carbon-carbon unsaturated double bonds; the compounds containing carbon-carbon unsaturated double bonds include styrene, N-phenylacrylamide, N-phenylmethacrylamide, ethylene oxide-2-methyl methacrylate, butyl acrylate, methacrylate-2-ethylhexyl, 2-(perfluorohexyl)ethyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, N-hydroxyethylacrylamide, dimethylaminoethyl methacrylate, isophorone diamine, naphthalene diisocyanate, acrylamide and methyl methacrylate.

10. The preparation method according to claim 7, characterized in that: The preparation method of the photosensitive small molecule comprises: S1) mixing hydrochloric acid, water and p-phenoxyaniline, cooling in an ice-water bath and stirring to obtain a first solution; S2) adding the second solution dropwise to the first solution to obtain a fourth solution after the addition is complete; the addition time is 15 min; S3) adding potassium carbonate solution dropwise to the fifth solution, adjusting the pH value to 9-10, stirring at room temperature for reaction, and extracting the organic phase with dichloromethane after the reaction, washing, drying, and distilling under reduced pressure to obtain the product.

11. A method for laser-assisted MicroLED mass transfer, characterized in that: The composite material according to any one of claims 1 to 6 is used as the dynamic release layer.

12. Use of the composite material according to any one of claims 1 to 6 as a dynamic release layer in laser-assisted MicroLED mass transfer.

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