A method for preparing porous ZnO film

Abstract

The invention belongs to the technical field of metal semiconductor thin films, and discloses a method for preparing a porous ZnO film, wherein zinc acrylate and 2-methylimidazole are added to acrylic acid to obtain a mixed solution after magnetic stirring and ultrasonic oscillation; then benzil and a photoinitiator are added to the mixed solution to uniformly form a zinc-based photocurable resin precursor after magnetic stirring and ultrasonic oscillation again; a spin coater is used to uniformly spin-coat the zinc-based photocurable resin precursor onto a silicon wafer, and long-wave ultraviolet rays are used to irradiate to generate an organic film of zinc acrylate-acrylic acid copolymer; a thermal treatment method is used to convert the organic film of zinc acrylate-acrylic acid copolymer into a porous ZnO film. The method has a simple preparation process, a high utilization rate of raw materials, almost no side reaction products and industrial waste, and the thickness of the prepared porous ZnO film is uniform and controllable, and has a good surface morphology.

Description

Technical Field

[0001] The invention belongs to the technical field of metal semiconductor thin films, and particularly relates to a method for preparing a porous ZnO thin film. Background Art

[0002] Zinc oxide (ZnO) is a well-known metal oxide material that exhibits excellent biocompatibility, semiconductor, optical, photocatalytic, resistive switching and piezoelectric properties. ZnO thin films can be widely used in various fields including ultraviolet photodetectors, photonodes, photocatalysis, etc. However, in applications such as biosensing and gas sensing, the low specific surface area characteristics of ZnO thin films hinder effective surface chemical modification, thereby reducing its sensing response and selectivity. In order to improve the specific surface area of ​​ZnO, some solutions have been proposed, such as low-dimensional structured ZnO materials. However, the synthesis method of low-dimensional structure is limited in terms of scalability over a large area. In fact, considering the industrial scalability and product integration of functional materials, the technology based on ZnO thin films is still one of the most effective solutions. At present, the most mainstream thin film preparation methods are physical vapor deposition, photopolymerization, wet chemical methods and template-assisted growth methods. Among them, photopolymerization has many advantages, such as the controllability of film thickness and the flatness of film surface morphology, and has great advantages in the field of preparing porous ZnO thin films. However, the commonly used photopolymerization methods all use extreme ultraviolet and deep ultraviolet light, which has high requirements on equipment; and the solvents used in the preparation process only play a role in dissolving the reactants, so the commonly used photopolymerization methods will produce a large amount of waste when preparing porous ZnO films. These are all problems that need to be solved in applying photopolymerization methods in large-scale industrial production. Summary of the invention

[0003] The invention provides a method for preparing a porous ZnO film based on the principle of photopolymerization. The prepared porous ZnO film has a uniform and controllable thickness and good surface morphology.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A method for preparing a porous ZnO film comprises the following steps: adding zinc acrylate and 2-methylimidazole into acrylic acid, stirring the mixture magnetically and oscillating the mixture ultrasonically to obtain a mixed solution; adding benzil and a photoinitiator into the mixed solution, stirring the mixture magnetically and oscillating the mixture ultrasonically to uniformly form a zinc-based photocurable resin precursor; using a spin coater to uniformly spin-coat the zinc-based photocurable resin precursor onto a silicon wafer, irradiating the mixture with long-wave ultraviolet rays to generate an organic film of zinc acrylate-acrylic acid copolymer; and using a heat treatment method to convert the organic film of zinc acrylate-acrylic acid copolymer into a porous ZnO film.

[0006] Furthermore, the mixing is carried out under stirring; the mass ratio of benzil to the photoinitiator is 1:1, and the total mass fraction of benzil and the photoinitiator in the precursor zinc-based photocurable resin is 2-3%.

[0007] Furthermore, the wavelength of the long-wave ultraviolet rays is 340 to 380 nanometers, and the irradiation time of the long-wave ultraviolet rays is 25 to 35 seconds.

[0008] Furthermore, the rate during spin coating is 3000-6000 rpm, and the spin coating time is 10 seconds.

[0009] Furthermore, the heat treatment step includes: placing the zinc acrylate-acrylic acid copolymer organic film in a muffle furnace and treating it at 450-700° C. for 20-30 minutes.

[0010] Furthermore, the molar ratio of zinc acrylate to 2-methylimidazole is 1:2-2.1, and the zinc ion concentration in the zinc-based photocurable resin precursor is 0.3-0.5 mol / L.

[0011] Furthermore, the photoinitiator is 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone.

[0012] Furthermore, the silicon wafer is pretreated before spin coating, and the pretreatment steps include: using soap water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, and then using a plasma cleaner to clean after drying, and blowing with nitrogen.

[0013] Further, the zinc acrylate-acrylic acid copolymer organic film is first developed in acrylic acid for 4 to 6 minutes, and then developed in propylene glycol methyl ether acetate for 4 to 6 minutes.

[0014] The invention also provides a porous ZnO film prepared by the above method.

[0015] Furthermore, the method comprises: a first step of preparing a zinc-based photocurable resin precursor: adding zinc acrylate and 2-methylimidazole to acrylic acid and stirring to obtain a mixed solution; then adding benzil and a photoinitiator to the mixed solution and stirring evenly to form a zinc-based photocurable resin precursor.

[0016] The second step is to prepare the zinc-based organic film: use a spin coater to evenly spin-coat the zinc-based photocurable resin precursor onto the silicon wafer, and irradiate it with long-wave ultraviolet light. Under the catalytic action of benzil and photoinitiator, the carbon-carbon double bonds of the zinc acrylate monomer and the acrylic acid monomer in the zinc-based photocurable resin are broken ( Figure 2 (a)), the two undergo polymerization reaction to form zinc acrylate-acrylic acid copolymer ( Figure 2 (b)), thereby obtaining a zinc-based organic film.

[0017] In the third step, the zinc-based organic film is converted into a porous ZnO film by heat treatment.

[0018] The method has simple preparation process, high raw material utilization rate, almost no side reaction products and industrial waste, and the prepared porous ZnO film has controllable thickness and good surface morphology.

[0019] The method for preparing a porous zinc oxide film comprises the following steps:

[0020] (1) preparing a zinc-based photocurable resin precursor;

[0021] (2) Preparing a zinc-based organic film: pre-treating the surface of a silicon wafer; using a spin coater to evenly spin-coat a zinc-based photocurable resin precursor onto the silicon wafer, irradiating it with long-wave ultraviolet light to polymerize and form a zinc-based organic film; washing the zinc-based organic film;

[0022] (3) The zinc-based organic film is converted into a porous ZnO film by heat treatment.

[0023] Furthermore, in step (1), the steps of preparing the precursor zinc-based photocurable resin are as follows:

[0024] a) Take a clean centrifuge tube, place zinc acrylate (2(C3H3O2)·Zn) and 2-methylimidazole (C4H6N2) in the centrifuge tube, add acrylic acid (C3H4O2), stir magnetically for more than 5 minutes at room temperature, and then oscillate ultrasonically for more than 30 minutes until the solute is completely dissolved to obtain a transparent mixed solution;

[0025] b) benzil (C 14 H 10 O2) and photoinitiator 369 (C 23 H 30 N2O2) is added to the mixed solution, magnetically stirred for more than 30 minutes at room temperature, and then ultrasonically oscillated for more than 10 minutes to form a zinc-based photocurable resin precursor;

[0026] Further, in step (2), the wavelength of the long-wave ultraviolet light is 365 nanometers;

[0027] Furthermore, in step (2), the zinc acrylate-acrylic acid copolymer organic film is washed by first developing the zinc acrylate-acrylic acid copolymer organic film in acrylic acid for 5 minutes and then developing it in propylene glycol methyl ether acetate for 5 minutes;

[0028] Furthermore, the relative humidity during mixing is 15-30%, and the temperature is 15-40°C.

[0029] Beneficial Effects

[0030] The porous ZnO film preparation scheme described in the present invention is to coat a zinc-based photocurable resin precursor onto a silicon wafer, and polymerize the zinc-based photocurable resin using long-wave ultraviolet rays to finally form a porous ZnO film. The method has a simple preparation process, and the solvent participates in the polymerization as one of the reactants, so the raw material utilization rate is high, and there is almost no side reaction product and industrial waste. The reaction conditions are simple, because acrylic acid and zinc acrylate monomers can be polymerized under the catalytic action of benzil and a photoinitiator with only long-wave ultraviolet rays, so there is no need for extreme ultraviolet or deep ultraviolet conditions required by the prior art. The present invention controls the thickness of the zinc-based organic film after photopolymerization by the spin coating speed, and then controls the thickness of the ZnO film after heat treatment, so that the thickness of the prepared porous ZnO film is uniform and controllable. Since the surface tension of the photoresin solution is low, the surface is smooth after spin coating, there are no side reaction products and waste, and the zinc-based organic film is flat and smooth after photopolymerization, so that the ZnO film after heat treatment has a good surface morphology. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Flow chart for preparing porous ZnO thin film;

[0032] Figure 2 Schematic diagram of the polymerization process to form a zinc-based organic film ( Figure 2 (a) is the bond-breaking principle, Figure 2 (b) is the polymerization principle);

[0033] Figure 3 This is an example diagram of a porous zinc oxide film in Example 1 of the present invention;

[0034] Figure 4 is the XRD pattern of the porous zinc oxide film in Example 1 of the present invention;

[0035] Figure 5 This is a front SEM image of the porous zinc oxide film in Example 1 of the present invention;

[0036] Figure 6 is a cross-sectional SEM image of the porous zinc oxide film in Example 1 of the present invention;

[0037] Figure 7 This is a front SEM image of the porous zinc oxide film in Example 2;

[0038] Figure 8 is a cross-sectional SEM image of the porous zinc oxide film in Example 2;

[0039] Fig. 9 This is a front SEM image of the porous zinc oxide film in Example 3;

[0040] Fig.10 is a cross-sectional SEM image of the porous zinc oxide film in Example 3;

[0041] Fig.11 This is a front SEM image of the porous zinc oxide film in Example 4;

[0042] Fig.12 This is a front SEM image of the porous zinc oxide film in Comparative Example 1;

[0043] Fig.13 is a cross-sectional SEM image of the porous zinc oxide film in Comparative Example 1;

[0044] Fig.14 This is the front SEM image of the porous zinc oxide film in Comparative Example 2. DETAILED DESCRIPTION

[0045] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the essence of the present invention, modifications and substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0046] Example 1

[0047] The porous ZnO film described in the present invention is firstly prepared with a zinc-based photocurable resin precursor: zinc acrylate and 2-methylimidazole are added to acrylic acid and stirred to obtain a mixed solution; then benzil and a photoinitiator are added to the mixed solution and stirred to form a zinc-based photocurable resin precursor. Secondly, a zinc-based organic film is prepared: firstly, the zinc-based photocurable resin precursor is evenly spin-coated onto a silicon wafer using a spin coater, and then irradiated with long-wave ultraviolet rays. Under the catalytic action of benzil and the photoinitiator, the zinc acrylate monomer and the acrylic acid monomer in the zinc-based photocurable resin undergo a polymerization reaction to generate a zinc-based organic film. Finally, a heat treatment method is used to convert the zinc-based organic film into a porous ZnO film. The present invention is described in detail below in conjunction with the accompanying drawings.

[0048] A preparation process of a porous ZnO film is as follows: Figure 1 As shown, the specific steps include the following:

[0049] First, take a 50 ml centrifuge tube, put 480 mg of zinc acrylate and 400 mg of 2-methylimidazole into the centrifuge tube, then add 3.5 ml of acrylic acid, stir magnetically at a speed of 1500 rpm for more than 5 minutes at room temperature to mix the solutes evenly, then oscillate ultrasonically at a power of 240 W for more than 30 minutes until the solutes are completely dissolved to obtain a transparent mixed solution; then add 54 mg of benzil and 54 mg of photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone) into the mixed solution, stir magnetically at a speed of 1500 rpm for more than 30 minutes at room temperature, then oscillate ultrasonically at a power of 240 W for more than 10 minutes;

[0050] When pre-treating the silicon wafer surface, use soapy water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, each cleaning step lasts 10 minutes, and then use a plasma cleaner to clean for 2 minutes after drying, and blow with nitrogen for 10 seconds;

[0051] Place the treated silicon wafer on a spin coater, drop 60 μL of the precursor zinc-based photocurable resin on the silicon wafer, and spin coat at 3500 rpm for 10 seconds;

[0052] The silicon wafer coated with the precursor zinc-based photocurable resin after spin coating is placed on a platform and irradiated with long-wave ultraviolet light with a wavelength of 365 nanometers for 30 seconds to polymerize and obtain a zinc-based organic film.

[0053] The zinc-based organic film was placed in a muffle furnace and treated at 450 degrees Celsius for 20 minutes to obtain a porous ZnO film. Figure 3 The X-ray diffraction pattern (XRD) of the film is shown as Figure 4 As shown in Figure 2, only the diffraction peak of ZnO was observed, proving that a high-purity ZnO film was generated; the front scanning electron microscope (SEM) image of the film is shown in Figure 2 Figure 5 As shown in the figure, it can be seen that the zinc oxide film has a porous structure and a dense surface, and the zinc oxide particle size is about 30nm; the cross-sectional scanning electron microscope (SEM) image of the film is shown in the figure Figure 6 As shown, it can be seen that the thickness of the zinc oxide film is uniform, about 90nm.

[0054] Example 2

[0055] First, take a 50 ml centrifuge tube, put 480 mg of zinc acrylate and 400 mg of 2-methylimidazole into the centrifuge tube, then add 5.2 ml of acrylic acid, stir magnetically for more than 5 minutes at room temperature to mix the solute evenly, then oscillate ultrasonically for more than 30 minutes until the solute is completely dissolved to obtain a transparent mixed solution; then add 80 mg of benzil and 80 mg of photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-

[0056] (4-morpholinobenzylphenyl)butanone) was added to the mixed solution, magnetically stirred for more than 30 minutes at room temperature, and then ultrasonically vibrated for more than 10 minutes;

[0057] When pre-treating the silicon wafer surface, use soapy water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, each cleaning step lasts 10 minutes, and then use a plasma cleaner to clean for 2 minutes after drying, and blow with nitrogen for 10 seconds;

[0058] Place the treated silicon wafer on a spin coater, drop 60 μL of the precursor zinc-based photocurable resin on the silicon wafer, and spin coat at 3500 rpm for 10 seconds;

[0059] The silicon wafer coated with the precursor zinc-based photocurable resin after spin coating is placed on a platform and irradiated with long-wave ultraviolet light with a wavelength of 365 nanometers for 30 seconds to polymerize and obtain a zinc-based organic film.

[0060] The zinc-based organic film was placed in a muffle furnace and treated at 450 degrees Celsius for 20 minutes to obtain a porous ZnO film. The front scanning electron microscope (SEM) image of the film is shown in Figure 7 As shown in Figure 2, it can be seen that the surface morphology of the zinc oxide film has not changed significantly; the cross-sectional scanning electron microscope (SEM) image of the film is shown in Figure 2 Figure 8 As shown, it can be seen that the thickness of the zinc oxide film is reduced to about 30 nanometers.

[0061] Example 3

[0062] First, take a 50 ml centrifuge tube, put 480 mg of zinc acrylate and 400 mg of 2-methylimidazole into the centrifuge tube, then add 3.5 ml of acrylic acid, stir magnetically for more than 5 minutes at room temperature to mix the solutes evenly, then oscillate ultrasonically for more than 30 minutes until the solutes are completely dissolved to obtain a transparent mixed solution; then add 54 mg of benzil and 54 mg of photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-

[0063] (4-morpholinobenzylphenyl)butanone) was added to the mixed solution, magnetically stirred for more than 30 minutes at room temperature, and then ultrasonically vibrated for more than 10 minutes;

[0064] When pre-treating the silicon wafer surface, use soapy water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, each cleaning step lasts 10 minutes, and then use a plasma cleaner to clean for 2 minutes after drying, and blow with nitrogen for 10 seconds;

[0065] Place the treated silicon wafer on a spin coater, drop 60 μL of the precursor zinc-based photocurable resin on the silicon wafer, and spin coat at 5000 rpm for 10 seconds;

[0066] The silicon wafer coated with the precursor zinc-based photocurable resin after spin coating is placed on a platform and irradiated with long-wave ultraviolet light with a wavelength of 365 nanometers for 30 seconds to polymerize and obtain a zinc-based organic film.

[0067] The zinc-based organic film was placed in a muffle furnace and treated at 450 degrees Celsius for 20 minutes to obtain a porous ZnO film. The front scanning electron microscope (SEM) image of the film is shown in Fig. 9 As shown in Figure 2, it can be seen that the surface morphology of the zinc oxide film has not changed; the cross-sectional scanning electron microscope (SEM) image of the film is shown in Figure 2 Fig.10 As shown, it can be seen that the thickness of the zinc oxide film becomes lower, at about 70 nanometers.

[0068] Example 4

[0069] First, take a 50 ml centrifuge tube, put 480 mg of zinc acrylate and 400 mg of 2-methylimidazole into the centrifuge tube, then add 3.5 ml of acrylic acid, stir magnetically for more than 5 minutes at room temperature to mix the solutes evenly, then oscillate ultrasonically for more than 30 minutes until the solutes are completely dissolved to obtain a transparent mixed solution; then add 54 mg of benzil and 54 mg of photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-

[0070] (4-morpholinobenzylphenyl)butanone) was added to the mixed solution, magnetically stirred for more than 30 minutes at room temperature, and then ultrasonically vibrated for more than 10 minutes;

[0071] When pre-treating the silicon wafer surface, use soapy water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, each cleaning step lasts 10 minutes, and then use a plasma cleaner to clean for 2 minutes after drying, and blow with nitrogen for 10 seconds;

[0072] Place the treated silicon wafer on a spin coater, drop 60 μL of the precursor zinc-based photocurable resin on the silicon wafer, and spin coat at 3500 rpm for 10 seconds;

[0073] The silicon wafer coated with the precursor zinc-based photocurable resin after spin coating is placed on a platform and irradiated with long-wave ultraviolet light with a wavelength of 365 nanometers for 30 seconds to polymerize and obtain a zinc-based organic film.

[0074] The zinc-based organic film was placed in a muffle furnace and treated at 680 degrees Celsius for 20 minutes to obtain a porous ZnO film. The front scanning electron microscope (SEM) image of the film is shown in Fig.11 As shown, it can be seen that the surface morphology of the zinc oxide film has not changed significantly, but the zinc oxide particle size has increased to about 45 nanometers.

[0075] Comparative Example 1

[0076] First, take a 50 ml centrifuge tube, put 480 mg of zinc acrylate and 400 mg of 2-methylimidazole into the centrifuge tube, then add 10.4 ml of acrylic acid, stir magnetically for more than 5 minutes at room temperature to mix the solutes evenly, then oscillate ultrasonically for more than 30 minutes until the solutes are completely dissolved to obtain a transparent mixed solution; then add 160 mg of benzil and 160 mg of photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone) into the mixed solution, stir magnetically for more than 30 minutes at room temperature, then oscillate ultrasonically for more than 10 minutes;

[0077] When pre-treating the silicon wafer surface, use soapy water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, each cleaning step lasts 10 minutes, and then use a plasma cleaner to clean for 2 minutes after drying, and blow with nitrogen for 10 seconds;

[0078] Place the treated silicon wafer on a spin coater, drop 60 μL of the precursor zinc-based photocurable resin on the silicon wafer, and spin coat at 3500 rpm for 10 seconds;

[0079] The silicon wafer coated with the precursor zinc-based photocurable resin after spin coating is placed on a platform and irradiated with long-wave ultraviolet light with a wavelength of 365 nanometers for 30 seconds to polymerize and obtain a zinc-based organic film.

[0080] The zinc-based organic film was placed in a muffle furnace and treated at 450 degrees Celsius for 20 minutes to obtain a porous ZnO film. The front scanning electron microscope (SEM) image of the film is shown in Fig.12 As shown in Figure 2, it can be seen that the zinc oxide film has lost its porous structure; the cross-sectional scanning electron microscope (SEM) image of the film is shown in Figure 2 Fig.13 As shown, it can be seen that the average thickness of the zinc oxide film is about 10 nanometers. From Comparative Example 1, it can be seen that when the zinc-based photocurable resin precursor is configured, if the zinc ion concentration is lower than the range of the embodiment, a porous ZnO film cannot be formed.

[0081] Comparative Example 2

[0082] First, take a 50 ml centrifuge tube, put 480 mg of zinc acrylate and 400 mg of 2-methylimidazole into the centrifuge tube, then add 1.6 ml of acrylic acid, stir magnetically at a speed of 1500 rpm for more than 5 minutes at room temperature to mix the solutes evenly, then oscillate ultrasonically at a power of 240 W for more than 30 minutes until the solutes are completely dissolved to obtain a transparent mixed solution; then add 54 mg of benzil and 54 mg of photoinitiator 369 (2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone) into the mixed solution, stir magnetically at a speed of 1500 rpm for more than 30 minutes at room temperature, then oscillate ultrasonically at a power of 240 W for more than 10 minutes;

[0083] When pre-treating the silicon wafer surface, use soapy water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, each cleaning step lasts 10 minutes, and then use a plasma cleaner to clean for 2 minutes after drying, and blow with nitrogen for 10 seconds;

[0084] Place the treated silicon wafer on a spin coater, drop 60 μL of the precursor zinc-based photocurable resin on the silicon wafer, and spin coat at 3500 rpm for 10 seconds;

[0085] The silicon wafer coated with the precursor zinc-based photocurable resin after spin coating is placed on a platform and irradiated with long-wave ultraviolet light with a wavelength of 365 nanometers for 30 seconds to polymerize and obtain a zinc-based organic film.

[0086] The zinc-based organic film was placed in a muffle furnace and treated at 450 degrees Celsius for 20 minutes to obtain a porous ZnO film. The front scanning electron microscope (SEM) image of the film is shown in Fig.14As shown, it can be seen that obvious defects appear on the surface of the zinc oxide film. From Comparative Example 2, it can be seen that when the zinc-based photocurable resin precursor is configured, if the zinc ion concentration is higher than the range of the embodiment, the formed ZnO film has obvious defects.

[0087] The above shows and describes the basic principles, main features and advantages of the present invention. The film thickness can vary with the zinc ion concentration in the zinc-based photocurable resin precursor and the spin coating speed; the ZnO particle size can vary with the annealing temperature. However, the above is only a specific embodiment of the present invention, and the technical features of the present invention are not limited thereto. Any other implementation methods derived by any technician in the field without departing from the technical solution of the present invention should be included in the patent scope of the present invention.

Claims

1. A method for preparing a porous ZnO thin film, characterized in that: The following steps are involved: Zinc acrylate and 2-methylimidazole are added to acrylic acid, and the mixture is stirred magnetically and ultrasonically vibrated to obtain a mixed solution; benzil and a photoinitiator are then added to the mixed solution, and the mixture is stirred magnetically and ultrasonically vibrated again to uniformly form a zinc-based photocurable resin precursor; the zinc-based photocurable resin precursor is evenly spin-coated onto a silicon wafer using a spin coater, and irradiated with long-wave ultraviolet rays to generate an organic film of zinc acrylate-acrylic acid copolymer; the organic film of zinc acrylate-acrylic acid copolymer is converted into a porous ZnO film using a heat treatment method; the zinc ion concentration in the zinc-based photocurable resin precursor is 0.3-0.7 mol / L.

2. The preparation method according to claim 1, characterized in that The mixing is carried out under stirring; the mass ratio of benzil to the photoinitiator is 1:1, and the total mass fraction of benzil and the photoinitiator in the precursor zinc-based photocurable resin is 2-3%.

3. The preparation method according to claim 1, characterized in that: The wavelength of the long-wave ultraviolet rays is 340-380 nanometers, and the irradiation time of the long-wave ultraviolet rays is 25-35 seconds.

4. The preparation method according to claim 1, characterized in that: The speed during spin coating is 3000-6000 rpm, and the spin coating time is 10 seconds.

5. The preparation method according to claim 1, characterized in that: The heat treatment step comprises: placing the zinc acrylate-acrylic acid copolymer organic film in a muffle furnace and treating it at 450-700° C. for 20-30 minutes.

6. The preparation method according to claim 1, characterized in that: The molar ratio of zinc acrylate to 2-methylimidazole is 1:2-2.

1.

7. The preparation method according to claim 1, characterized in that: The photoinitiator is 2-phenylbenzyl-2-dimethylamine-1-(4-morpholinobenzylphenyl)butanone.

8. The preparation method according to claim 1, characterized in that: The silicon wafer is pretreated before spin coating, and the pretreatment steps include: using soap water, deionized water, and ethanol ultrasonic oscillation cleaning in sequence, drying, and then using a plasma cleaning machine to clean, and blowing with nitrogen.

9. A porous ZnO film, characterized in that: Prepared by the method according to any one of claims 1 to 8.

Images