Silver nanowire / zinc oxide array structure composite transparent conductive film and preparation method thereof

Abstract

The invention discloses a silver nanowire / zinc oxide array structure composite transparent conductive film and a preparation method thereof, and relates to the field of material chemistry. Specifically, a zinc oxide nano tree array structure is prepared through a two-step method, in the first step, a zinc oxide nano particle seed layer is prepared on a substrate material, in the second step, the zinc oxide nano tree array structure grows on the seed layer, and then a three-dimensional nano tree array is coated with silver nanowires through a spin-coating method. And forming the composite transparent conductive film with the silver nanowire / zinc oxide array structure. According to the material, the optical anti-reaction effect of the zinc oxide nano tree film is utilized, the zinc oxide nano trees which are evenly distributed in a three-dimensional mode support and are connected with the silver nanowires, the contact resistance can be remarkably reduced, the optical and electrical properties of a single silver nanowire film are comprehensively improved, and the material has excellent photocatalysis, interface hydrophilicity, flexibility and stability. The material has wide prospects in design and application in the fields of wearable sensors, biological flexible electrodes and the like.

Description

Technical Field

[0001] The present invention belongs to the field of material chemistry, and particularly relates to a preparation method of a composite transparent conductive film of zinc oxide nanowire arrays and silver nanowires. Background Art

[0002] Transparent conductive films are widely used in optoelectronic devices such as solar cells, touchscreens, and light-emitting diodes. [(1) Liqiang Yang, Tim Zhang, Huaxing Zhou, et al. ACS applied materials &interfaces, 2011, 3, 4075–4084. (2) Jungjin Yoon, Unsoo Kim, Yongseok Yoo, etal. Advanced science, 2021, 8, 2004092. (3) Anuj R Madaria, Akshay Kumar, andChongwu Zhou. Nanotechnology, 2011, 22, 245201. (4) Xiaoyan Zeng, QikaiZhang, Rongmin Yu, et al. Advanced materials (Weinheim), 2010, 22, 4484–4488.(5) Robi S. Datta, Nitu Syed, Ali Zavabeti, et al. Nature electronics, 2020,3, 51–58.] Compared with the traditional transparent conductive film material indium tin oxide, silver nanowires have attracted extensive attention due to their excellent electrical conductivity, flexibility, high transparency, low cost, and easy industrial production. As an important component in optoelectronic devices, the optical and electrical properties of transparent conductive films are the key factors affecting their applications. Researchers mainly improve the optoelectronic properties, interfacial properties, and stability of silver nanowire films by compounding silver nanowires with other materials, [ (1)Alexandra Madeira, Marie Plissonneau, Laurent Servant, et al. Nanomaterials(Basel, Switzerland), 2019, 9, 899. (2) Li Gan, Ying Liu, Xiaojiao Yang, etal. Critical reviews in solid state and materials sciences, 2025, 50, 1-53.] However, these studies are limited by the simple compounding of two-dimensional structures, with limited potential for performance improvement, which restricts the further research of these composite structures. Summary of the Invention

[0003] The object of the present invention is to provide a preparation method of a multifunctional silver nanowire / zinc oxide array structure composite transparent conductive film. The technical problem to be solved is to introduce a three-dimensional array structure to composite and modify silver nanowires, prepare a transparent conductive film with synergistic high light transmittance and high conductivity functions, and achieve comprehensive improvement of optoelectronic properties and excellent multifunctionality. The present invention prepares a zinc oxide nanodendrite array structure by a two-step method, and directly composites silver nanowires on the array structure by a spin coating method, avoiding complicated transfer operations, and utilizing the unique interaction between silver nanowires and zinc oxide in the three-dimensional structure to expand the application possibilities of the composite structure. The prepared novel transparent conductive film with a silver nanowire / zinc oxide array structure composite realizes excellent light transmittance and conductivity, exhibits good photocatalysis, interfacial hydrophilicity, flexibility and stability. Its application helps to improve the ability to degrade pollutants and biocompatibility, adapt to complex deformations, and extend the service life of the material.

[0004] The object of the present invention is achieved as follows: A preparation method of a silver nanowire / zinc oxide array structure composite transparent conductive film, characterized in that the method includes: designing and preparing a zinc oxide nanodendrite array structure by a two-step method, and directly coating silver nanowires on the array structure by a spin coating method to prepare a silver nanowire / zinc oxide array structure composite transparent conductive film with high optoelectronic properties. The specific steps are as follows: Step 1: Preparation of a ZnO nanoparticle seed layer substrate In a beaker, add diethanolammonium and zinc acetate to ethylene glycol monomethyl ether and stir for 10 - 30 min until all solids are dissolved. Then seal a layer of plastic wrap on the mouth of the beaker to avoid solvent volatilization. Place the mixed solution in a water bath and stir and react at 50 - 70 °C for 2 h. After cooling, obtain a ZnO sol; vertically immerse a glass sheet with a light transmittance of 91% into the ZnO sol by the dip coating method for 600 s and uniformly lift it. Repeat the coating 1 - 8 times to deposit a ZnO nanoparticle seed layer substrate. Place the prepared ZnO nanoparticle seed layer substrate in a muffle furnace and heat it to 300 °C at a heating rate of 5 °C·min-1 and calcine for 5 - 20 min, then heat it to 500 °C and calcine for 30 - 90 min; wherein, the molar ratio of diethanolammonium, zinc acetate and ethylene glycol monomethyl ether is 2:1:20 - 150; the uniform lifting speed is 5 - 50 mm·min-1; Step 2: Synthesis of a ZnO nanodendrite array structure film Dissolve zinc nitrate hexahydrate and hexamethylenetetramine (C6H12N4) in deionized water and stir for 10 - 30 min to dissolve, obtaining a growth solution. Vertically insert the ZnO nanoparticle seed layer substrate prepared in step 1 into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and let it stand and react at 90 °C for 0.5 - 3 h. Slowly take out the seed layer substrate from the growth solution, place the growth surface horizontally in a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C·min-1 and calcine for 0.5 - 2 h to obtain a ZnO nanowire array structure thin film; where the ratio of zinc nitrate hexahydrate, hexamethylenetetramine, and deionized water is 1 (mol)∶1 (mol)∶50 (L); Step 3: Preparation of silver nanowire dispersion Add PVP with a relative molecular mass of 1300000 to ethylene glycol, heat and stir in an oil bath at 160 °C for 1 - 2 h to fully dissolve PVP, obtaining a PVP ethylene glycol solution with a concentration of 0.005 - 0.020 g·mL-1. Then add NaCl and NaBr to the solution, heat and stir in an oil bath at 160 °C for 5 - 10 min to fully dissolve NaCl and NaBr, obtaining liquid A; dissolve Ag in ethylene glycol under dark conditions and stir for 20 min to obtain liquid B after full dissolution; add liquid A to a reaction vessel and seal it, introduce nitrogen into the vessel to remove the oxygen in the system, place it in an oil bath and heat to 160 °C, keep stirring, and slowly drip liquid B using a syringe. Keep liquid B in the dark during this process. After the dripping is completed, continue to stir for 2 min, turn off the stirring, and let it stand and react at 160 °C for 1.5 h to obtain a silver nanowire dispersion; where the mass ratio of NaCl and NaBr is 2:1, and the concentration of NaCl in liquid A is 0.1 - 0.5 mg·mL-1; liquid B is a 10 mg·mL-1 AgNO3 ethylene glycol solution; the volume ratio of liquid A to liquid B is 2:1; Next, post - treatment is carried out on the silver nanowire dispersion. After the silver nanowire solution is cooled to room temperature, acetone with a volume 1 - 2 times that of the solution is added to the solution, shaken well. After the solution is clearly stratified, the mixed solution is centrifuged, and the lower precipitate is retained. Then, absolute ethanol is added and shaken well to dissolve. After there is no obvious solid precipitate in the solution, the solution is centrifuged, and the lower precipitate is retained. Then, absolute ethanol is added again and shaken well to dissolve. After there is no obvious solid precipitate in the solution, the solution is centrifuged, and the lower precipitate is retained. Deionized water is added and shaken well to dissolve. After there is no obvious solid precipitate in the solution, the solution is centrifuged, and the lower precipitate is retained. Then, deionized water is added again and shaken well to dissolve. After there is no obvious solid precipitate in the solution, the solution is centrifuged, and the lower precipitate is retained; The precipitate is evenly dispersed in the dispersant and stored in the dark to obtain the silver nanowire dispersion; Among them, the centrifugation speed is 6000 - 8000 r·min-1, and the centrifugation time is 3 - 5 min; The dispersant is absolute ethanol and deionized water; Step 4: Preparation of silver nanowire / zinc oxide array structure composite transparent conductive film The ZnO nanodendrite array structure film prepared in Step 2 is spin - coated with the silver nanowire dispersion by the spin - coating method to obtain a single - layer silver nanowire / zinc oxide array structure composite transparent conductive film. Then, the silver nanowire dispersion is repeatedly spin - coated on the single - layer silver nanowire / zinc oxide array structure composite transparent conductive film to obtain the silver nanowire / zinc oxide array structure composite transparent conductive film.

[0005] Furthermore, the spin - coating method specifically includes: (a) First, the ZnO nanodendrite array structure film prepared in Step 2 is fixed in a tabletop spin coater by pumping vacuum with an oil pump, and the rotation speed is adjusted to 1000 - 4000 r·min-1. Take 50 - 100 μL of the 10 mg·mL-1 silver nanowire dispersion prepared in Step 3 and drop it on the surface during the rotation of the ZnO nanodendrite array structure film. After dropping, continue to rotate for 10 - 60 s; (b) Then, take out the film material from the tabletop spin coater and place it under an infrared lamp to dry for 3 - 5 min; (c) After the single - layer silver nanowire / zinc oxide array structure composite transparent conductive film is dried, repeat the operation 1 - 5 times at a rotation speed of 1000 - 4000 r·min-1. Take 50 - 100 μL of the 10 mg·mL-1 silver nanowire dispersion prepared in Step 3 and drop it on the surface during the rotation of the single - layer silver nanowire / zinc oxide array structure composite transparent conductive film. After dropping, continue to rotate for 10 - 60 s, and then place it under an infrared lamp to dry for 3 - 5 min; (d) The obtained composite transparent conductive film of silver nanowire / zinc oxide array structure has a mass of silver nanowires per square centimeter of 0.01 - 5 mg, and is compounded with the ZnO nanodendrite array structure film through 1 - 6 times of repeated spin - coating.

[0006] A composite transparent conductive film of silver nanowire / zinc oxide array structure prepared by the above - mentioned method.

[0007] In the present invention, the introduction of zinc oxide nanodendrites significantly improves the light transmittance of the composite - structure transparent conductive film compared with that of a single silver - nanowire film. The light transmittance at 550 nm can reach 89.60%. The three - dimensionally uniformly distributed zinc oxide nanodendrites support and connect silver nanowires like a wire rack, effectively reducing the contact resistance. The sheet resistance can reach 44.0 Ω·sq−1. At the same time, a regularly arranged conductive network is formed, significantly improving the conductivity uniformity of the film. The present invention is characterized in that a zinc oxide nanodendrite array structure is prepared by a two - step method, and the spin - coating method is used to directly coat silver nanowires on the array structure through a non - transfer step, preparing a composite nanostructure of silver nanowire / zinc oxide array structure. The three - dimensional array structure is used to modify silver nanowires, comprehensively improving the optical and electrical properties of the film.

[0008] The beneficial effects of the present invention: A three - dimensionally distributed zinc oxide nanodendrite array structure is synthesized by a two - step method, and silver nanowires are directly grown on the array structure, expanding the possibilities of silver - nanowire composite structures and comprehensively improving the limited properties of single silver - nanowire films. The novel transparent conductive film formed by compounding the prepared array structure with silver nanowires realizes the synergistic improvement of light transmittance and conductivity, and has excellent photocatalytic properties, interfacial hydrophilicity, flexibility and stability. Its application helps to improve the pollutant degradation performance, biocompatibility and anti - flexure performance, and extend the service life of the material. Description of the Drawings

[0009] Figure 1 It is the scanning electron microscope morphology diagram of the composite transparent conductive film of silver nanowire / zinc oxide array structure prepared by the present invention; Figure 2 It is the light transmittance curve diagram of the composite transparent conductive film of silver nanowire / zinc oxide array structure of the present invention; Figure 3 It is the absorbance curve diagram of rhodamine B solution during the photocatalytic degradation process of the composite transparent conductive film of silver nanowire / zinc oxide array structure of the present invention in the whole wavelength range and near the maximum absorption wavelength. Detailed Embodiments

[0010] The present invention will be further described below in conjunction with the drawings and embodiments to enhance the understanding of the present invention, but the present invention is by no means limited to the embodiments. Example

[0011] 1) Preparation of ZnO nanoparticle seed layer substrate 1.97 g (1.80 mL) of diethanolammonium and 8.23 g of zinc acetate were added to 100 mL of ethylene glycol monomethyl ether and stirred for 20 min until all the solids were dissolved. Then, a layer of plastic wrap was sealed on the mouth of the beaker to avoid solvent evaporation. The mixed solution was placed in a water bath and stirred at 60 °C for 2 h. After cooling, a 0.375 mol·L-1 ZnO sol was obtained. By the dip-coating method, a glass sheet with a light transmittance of 91% was vertically immersed in the ZnO sol for 600 s and uniformly pulled up at a speed of 10 mm·min-1. The coating was repeated 4 times to deposit a ZnO nanoparticle seed layer substrate. The prepared ZnO nanoparticle seed layer substrate was placed in a muffle furnace and heated to 300 °C at a heating rate of 5 °C·min-1 and calcined for 10 min, and then heated to 500 °C and calcined for 60 min.

[0012] 2) Synthesis of ZnO nanodendrite array structure thin film 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) were dissolved in 50 mL of deionized water and stirred for 20 min to dissolve, obtaining a growth solution. The prepared ZnO nanoparticle seed layer substrate was vertically inserted into the growth solution, and the glass sheet was fixed using a polypropylene template. It was placed in a water bath and allowed to stand and react at 90 °C for 2 h. The glass sheet was slowly taken out of the growth solution, and the growth surface was placed horizontally in a muffle furnace and heated to 500 °C at a heating rate of 5 °C·min-1 and calcined for 2 h to obtain a ZnO nanodendrite array structure thin film. Example

[0013] 1) Preparation of ZnO nanoparticle seed layer substrate 0.99 g of diethanolammonium and 4.12 g of zinc acetate were added to 100 mL of ethylene glycol monomethyl ether and stirred for 20 min until all the solids were dissolved. Then, a layer of plastic wrap was sealed on the mouth of the beaker to avoid solvent evaporation. The mixed solution was placed in a water bath and stirred at 60 °C for 2 h. After cooling, a 0.188 mol·L-1 ZnO sol was obtained. By the dip-coating method, a glass sheet with a light transmittance of 91% was vertically immersed in the ZnO sol for 600 s and uniformly pulled up at a speed of 10 mm·min-1. The coating was repeated 4 times to deposit a ZnO nanoparticle seed layer substrate. The prepared ZnO nanoparticle seed layer substrate was placed in a muffle furnace and heated to 300 °C at a heating rate of 5 °C·min-1 and calcined for 10 min, and then heated to 500 °C and calcined for 60 min.

[0014] 2) Synthesis of ZnO nanodendrite array structure thin film Dissolve 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) in 50 mL of deionized water and stir for 20 min to dissolve, obtaining a growth solution. Vertically insert the prepared ZnO nanoparticle seed layer substrate into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and let it stand and react at 90 °C for 2 h. Slowly take out the glass slide from the growth solution, place the growth surface horizontally in a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C·min-1 and calcine for 2 h to obtain a ZnO nanodendrite array structure thin film. Example

[0015] 1) Preparation of ZnO nanoparticle seed layer substrate Add 1.97 g (1.80 mL) of diethanolammonium and 8.23 g of zinc acetate to 100 mL of ethylene glycol monomethyl ether and stir for 20 min until all solids are dissolved. Then seal a layer of plastic wrap on the mouth of the beaker to avoid solvent evaporation. Place the mixed solution in a water bath and stir and react at 60 °C for 2 h. After cooling, obtain a 0.375 mol·L-1 ZnO sol; vertically immerse a glass slide with a light transmittance of 91% into the ZnO sol by the dip-coating method for 600 s, and uniformly lift it at a speed of 10 mm·min-1. Repeat the coating 2 times to deposit a ZnO nanoparticle seed layer substrate. Place the prepared ZnO nanoparticle seed layer substrate in a muffle furnace, heat it to 300 °C at a heating rate of 5 °C·min-1 and calcine for 10 min, and then heat it to 500 °C and calcine for 60 min.

[0016] 2) Synthesis of ZnO nanodendrite array structure thin film Dissolve 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) in 50 mL of deionized water and stir for 20 min to dissolve, obtaining a growth solution. Vertically insert the prepared ZnO nanoparticle seed layer substrate into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and let it stand and react at 90 °C for 2 h. Slowly take out the glass slide from the growth solution, place the growth surface horizontally in a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C·min-1 and calcine for 2 h to obtain a ZnO nanodendrite array structure thin film. Example

[0017] 1) Preparation of ZnO nanoparticle seed layer substrate 1.97 g (1.80 mL) of diethanolammonium and 8.23 g of zinc acetate were added to 100 mL of ethylene glycol methyl ether and stirred for 20 min until all the solids were dissolved. Then, a layer of plastic wrap was sealed on the mouth of the beaker to avoid solvent evaporation. The mixed solution was placed in a water bath and stirred at 60 °C for 2 h. After cooling, a ZnO sol with a concentration of 0.375 mol·L-1 was obtained. A glass slide with a light transmittance of 91% was vertically immersed in the ZnO sol by the dip-coating method for 600 s and uniformly pulled up at a speed of 10 mm·min-1. The coating was repeated 4 times to deposit a ZnO nanoparticle seed layer substrate. The prepared ZnO nanoparticle seed layer substrate was placed in a muffle furnace and heated to 300 °C at a heating rate of 5 °C·min-1 and calcined for 10 min, and then heated to 500 °C and calcined for 60 min.

[0018] 2) Synthesis of ZnO nanodendrite array structure thin film 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) were dissolved in 50 mL of deionized water and stirred for 20 min to dissolve, obtaining a growth solution. The prepared ZnO nanoparticle seed layer substrate was vertically inserted into the growth solution, and the glass slide was fixed using a polypropylene template. It was placed in a water bath and allowed to react statically at 90 °C for 1 h. The glass slide was slowly taken out of the growth solution, and the growth surface was placed horizontally in a muffle furnace and heated to 500 °C at a heating rate of 5 °C·min-1 and calcined for 2 h to obtain a ZnO nanodendrite array structure thin film. Example

[0019] 1) Preparation of ZnO nanoparticle seed layer substrate 1.97 g (1.80 mL) of diethanolammonium and 8.23 g of zinc acetate were added to 100 mL of ethylene glycol methyl ether and stirred for 20 min until all the solids were dissolved. Then, a layer of plastic wrap was sealed on the mouth of the beaker to avoid solvent evaporation. The mixed solution was placed in a water bath and stirred at 60 °C for 2 h. After cooling, a ZnO sol with a concentration of 0.375 mol·L-1 was obtained. A glass slide with a light transmittance of 91% was vertically immersed in the ZnO sol by the dip-coating method for 600 s and uniformly pulled up at a speed of 10 mm·min-1. The coating was repeated 4 times to deposit a ZnO nanoparticle seed layer substrate. The prepared ZnO nanoparticle seed layer substrate was placed in a muffle furnace and heated to 300 °C at a heating rate of 5 °C·min-1 and calcined for 10 min, and then heated to 500 °C and calcined for 60 min.

[0020] 2) Synthesis of ZnO nanodendrite array structure thin film Dissolve 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) in 50 mL of deionized water and stir for 20 min to dissolve, obtaining a growth solution. Vertically insert the prepared ZnO nanoparticle seed layer substrate into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and let it stand and react at 90 °C for 2 h. Slowly take out the glass slide from the growth solution, place the growth surface horizontally in a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C·min-1 and calcine for 2 h to obtain a ZnO nanowire array structure thin film.

[0021] 3) Preparation of silver nanowire / zinc oxide array structure composite transparent conductive thin film Using the spin coating method, spin coat 50 μL of a 10 mg·mL-1 silver nanowire dispersion solution on the ZnO nanowire array structure thin film at a rotation speed of 3000 r·min-1. Place the glass slide under an infrared lamp and dry it for 3 min to obtain a single-layer silver nanowire / zinc oxide array structure composite transparent conductive thin film. Then, repeat the process of spin coating 50 μL of a 10 mg·mL-1 silver nanowire dispersion solution on the single-layer silver nanowire / zinc oxide array structure composite transparent conductive thin film at a rotation speed of 3000 r·min-1 and place it under the infrared lamp and dry it for 3 times to obtain a silver nanowire / zinc oxide array structure composite transparent conductive thin film. The morphology of the silver nanowire / zinc oxide array structure is as Figure 1 shown. Example

[0022] 1) Preparation of ZnO nanoparticle seed layer substrate Add 1.97 g (1.80 mL) of diethanolamine and 8.23 g of zinc acetate to 100 mL of ethylene glycol monomethyl ether and stir for 20 min until all the solids are dissolved. Then, seal the mouth of the beaker with a layer of plastic wrap to avoid solvent evaporation. Place the mixed solution in a water bath and stir and react at 60 °C for 2 h. After cooling, obtain a 0.375 mol·L-1 ZnO sol. Vertically immerse a glass slide with a light transmittance of 91% into the ZnO sol by the dip coating method for 600 s, and uniformly lift it at a speed of 10 mm·min-1. Repeat the coating 4 times to deposit a ZnO nanoparticle seed layer substrate. Place the prepared ZnO nanoparticle seed layer substrate in a muffle furnace, heat it to 300 °C at a heating rate of 5 °C·min-1 and calcine for 10 min, and then heat it to 500 °C and calcine for 60 min.

[0023] 2) Synthesis of ZnO nanowire array structure thin film Dissolve 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) in 50 mL of deionized water and stir for 20 min to dissolve, obtaining a growth solution. Vertically insert the prepared ZnO nanoparticle seed layer substrate into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and let it stand and react at 90 °C for 2 h. Slowly take out the glass slide from the growth solution, place the growth surface horizontally in a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C·min-1 and calcine for 2 h to obtain a ZnO nanowire array structure thin film.

[0024] 3) Preparation of silver nanowire / zinc oxide array structure composite transparent conductive thin film For the prepared ZnO nanowire array structure thin film, by spin coating method, spin coat 50 μL of a 10 mg·mL-1 silver nanowire dispersion liquid on the ZnO nanowire array structure thin film at a rotation speed of 3000 r·min-1. Place the glass slide under an infrared lamp for 3 min to dry, obtaining a single-layer silver nanowire / zinc oxide array structure composite transparent conductive thin film. Then repeat the process of spin coating 50 μL of a 10 mg·mL-1 silver nanowire dispersion liquid on the single-layer silver nanowire / zinc oxide array structure composite transparent conductive thin film at a rotation speed of 3000 r·min-1 and place it under an infrared lamp for 3 min to dry once to obtain a silver nanowire / zinc oxide array structure composite transparent conductive thin film. Examples

[0025] 1) Preparation of ZnO nanoparticle seed layer substrate Add 1.97 g (1.80 mL) of diethanolamine and 8.23 g of zinc acetate to 100 mL of ethylene glycol monomethyl ether and stir for 20 min until all solids are dissolved. Then seal a layer of plastic wrap on the mouth of the beaker to avoid solvent volatilization. Place the mixed solution in a water bath and stir and react at 60 °C for 2 h. After cooling, obtain a 0.375 mol·L-1 ZnO sol; vertically immerse a glass slide with a light transmittance of 91% into the ZnO sol by dip coating for 600 s and uniformly lift it at a speed of 10 mm·min-1. Repeat the coating 4 times to deposit a ZnO nanoparticle seed layer substrate. Place the prepared ZnO nanoparticle seed layer substrate in a muffle furnace, heat it to 300 °C at a heating rate of 5 °C·min-1 and calcine for 10 min, and then heat it to 500 °C and calcine for 60 min.

[0026] 2) Synthesis of ZnO nanowire array structure thin film Dissolve 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) in 50 mL of deionized water and stir for 20 min to dissolve, obtaining a growth solution. Vertically insert the prepared ZnO nanoparticle seed layer substrate into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and let it stand and react at 90 °C for 2 h. Slowly take out the glass slide from the growth solution, place the growth surface horizontally in a muffle furnace, and heat it to 500 °C at a heating rate of 5 °C·min-1 and calcine for 2 h to obtain a ZnO nanowire array structure thin film.

[0027] 3) Preparation of silver nanowire / zinc oxide array structure composite transparent conductive thin film For the prepared ZnO nanowire array structure thin film, by spin coating method, spin coat 50 μL of a 10 mg·mL-1 silver nanowire dispersion solution on the ZnO nanowire array structure thin film at a rotation speed of 2000 r·min-1. Place the glass slide under an infrared lamp for 3 min to dry, obtaining a single-layer silver nanowire / zinc oxide array structure composite transparent conductive thin film. Then repeat the process of spin coating 50 μL of a 10 mg·mL-1 silver nanowire dispersion solution on the single-layer silver nanowire / zinc oxide array structure composite transparent conductive thin film at a rotation speed of 3000 r·min-1 and place it under an infrared lamp for 3 min to dry for 3 times to obtain a silver nanowire / zinc oxide array structure composite transparent conductive thin film. Examples

[0028] 1) Preparation of ZnO nanoparticle seed layer substrate Add 1.97 g (1.80 mL) of diethanolammonium and 8.23 g of zinc acetate to 100 mL of ethylene glycol methyl ether and stir for 20 min until all solids are dissolved. Then seal a layer of plastic wrap on the mouth of the beaker to avoid solvent volatilization. Place the mixed solution in a water bath and stir and react at 60 °C for 2 h. After cooling, obtain a 0.375 mol·L-1 ZnO sol; vertically immerse a polyethylene terephthalate sheet (PET) into the ZnO sol by dip coating for 600 s and uniformly lift it at a speed of 10 mm·min-1. Repeat the coating 4 times to deposit a ZnO nanoparticle seed layer substrate. Place the prepared ZnO nanoparticle seed layer substrate in an oven at 50 °C and dry for 2 h.

[0029] 2) Synthesis of ZnO nanowire array structure thin film Dissolve 0.30 g of ZnNO3·6H2O and 0.14 g of C6H12N4 (hexamethylenetetramine) in 50 mL of deionized water and stir for 20 min to dissolve, obtaining a growth solution. Vertically insert the prepared ZnO nanoparticle seed layer substrate into the growth solution, and use a polypropylene template to fix the glass slide. Place it in a water bath and react statically at 90 °C for 2 h. Slowly take out the PET from the growth solution, place the growth surface horizontally in an oven at 50 °C, and dry for 2 h to obtain a flexible film with a ZnO nanowire array structure.

[0030] (3) Preparation of silver nanowire / zinc oxide array structure composite transparent conductive film For the prepared flexible film with a ZnO nanowire array structure, spin-coat 50 μL of a 10 mg·mL-1 silver nanowire dispersion solution on it at a speed of 3000 r·min-1 by spin-coating method. Place the PET under an infrared lamp for 3 min to dry, obtaining a single-layer silver nanowire / zinc oxide array structure composite flexible transparent conductive film. Then repeat the process of spin-coating 50 μL of a 10 mg·mL-1 silver nanowire dispersion solution on the single-layer silver nanowire / zinc oxide array structure composite flexible transparent conductive film at a speed of 3000 r·min-1 and placing it under an infrared lamp for 3 min to dry for 3 times, obtaining a silver nanowire / zinc oxide array structure composite flexible transparent conductive film.

[0031] Characterization and performance evaluation of the samples obtained in the examples (1) Morphology characterization of the film Characterize the structural properties of the transparent conductive film of the film sample obtained in the present invention by field emission scanning electron microscopy (FE-SEM, Hitachi S-4800).

[0032] (2) Optical and electrical property characterization Use a UV-visible spectrophotometer (UV-8000, Metash) to test the transmittance of the silver nanowire / zinc oxide array structure composite transparent conductive film obtained in the present invention at 550 nm; measure the sheet resistance of the film by a digital four-probe tester (ST2258C, Suzhou Jingle Electronics Co., Ltd.).

[0033] As Figure 1SEM image of the silver nanowire / zinc oxide array structure composite transparent conductive film of the present invention. It can be seen that the nano zinc oxide acts as a dendritic scaffold to support and connect the silver nanowires, enabling the silver nanowires to be more evenly arranged on the three-dimensional array and achieving higher conductivity uniformity. The zinc oxide nanodendrites can enhance the contact at the joints of different silver nanowires and reduce the contact resistance. The sheet resistance after being compounded with the zinc oxide nanodendrite array structure decreases from 101.7 Ω·sq-1 to 44.0 Ω·sq-1. Figure 2 The transmittance curve of the silver nanowire / zinc oxide array structure composite transparent conductive film. The zinc oxide nanodendrite array structure enhances the light transmittance by reducing the light absorption of the material. Compared with the single silver nanowire film, the transmittance at a wavelength of 550 nm increases from 83.67% to 89.60%.

[0034] (3)Multifunctional characterization The silver nanowire / zinc oxide array structure composite transparent conductive film obtained in the present invention was placed in a 10 mg·L−1 rhodamine B solution, and the high-pressure mercury lamp and the condensed water were turned on and placed for 60 min under light conditions. The absorbance of the sample was measured with a UV-visible spectrophotometer (UV-8000, Metash), and the photocatalytic degradation efficiency of the rhodamine B solution was calculated therefrom. The transmittance of the rhodamine B solution at a wavelength of 553 nm shows a downward trend with time (such as Figure 3 The absorbance curves of the rhodamine B solution in the entire wavelength range (Figure a) and near the maximum absorption wavelength during the photocatalytic degradation process (Figure b) indicate that the silver nanowire / zinc oxide array structure composite transparent conductive film has an obvious catalytic effect on the photocatalytic degradation of the rhodamine B solution, indicating that the silver nanowire / zinc oxide array structure composite transparent conductive film has excellent photocatalytic performance.

[0035] The contact angles of water on the glass substrate, zinc oxide film, and silver nanowire / zinc oxide composite film were measured using the sessile drop method (Shanghai Zhongchen, JC2000DS). The contact angle of water on the silver nanowire / zinc oxide array structure composite transparent conductive film is significantly lower than that of water on the glass, indicating that the silver nanowire / zinc oxide array structure composite transparent conductive film has excellent hydrophilic properties.

Claims

1. A method for preparing a silver nanowire / zinc oxide array structure composite transparent conductive film, characterized in that: The method comprises the following specific steps: Step 1: Preparation of ZnO nanoparticle seed layer substrate In a beaker, diethanolammonium and zinc acetate are added to ethylene glycol methyl ether and stirred for 10-30 min to dissolve all the solids, then a layer of plastic wrap is sealed on the top of the beaker to prevent the solvent from volatilizing, the mixed solution is placed in a water bath and stirred at 50-70 ° C for 2 h, and ZnO sol is obtained after cooling; a glass sheet with a transmittance of 91% is vertically immersed in the ZnO sol for 600 s, and pulled evenly, and the coating is repeated 1-8 times to coat a layer of ZnO nanoparticle seed layer substrate, and the prepared ZnO nanoparticle seed layer substrate is placed in a muffle furnace, and the temperature is raised to 300 ° C at a heating rate of 5 ° C·min-1 for calcination for 5-20 min, and then the temperature is raised to 500 ° C for calcination for 30-90 min; wherein the molar ratio of diethanolammonium, zinc acetate and ethylene glycol methyl ether is 2:1:20-150; the uniform pulling rate is 5-50 mm·min-1; Step 2: Synthesis of ZnO nanotree array structure film Dissolve zinc nitrate hexahydrate and hexamethylenetetramine in deionized water and stir for 10-30 min to dissolve to obtain a growth solution, vertically insert the ZnO nanoparticle seed layer substrate prepared in step 1 into the growth solution, and use a polypropylene template to fix a glass sheet, place it in a water bath and react at 90°C for 0.5-3 h, slowly take the seed layer substrate out of the growth solution, place the growth surface horizontally in a muffle furnace, heat it to 500°C at a heating rate of 5°C·min-1, and calcine it for 0.5-2 h to obtain a ZnO nanotree array structure film; wherein the ratio of zinc nitrate hexahydrate, hexamethylenetetramine and deionized water is 1 (mol): 1 (mol): 50 (L); Step 3: Preparation of silver nanowire dispersion PVP with a relative molecular mass of 1300000 is added to ethylene glycol, and heated in an oil bath at 160°C with stirring for 1-2 h to fully dissolve PVP to obtain an ethylene glycol solution of PVP with a concentration of 0.005-0.020 g·mL-1. NaCl and NaBr are then added to the solution, and heated in an oil bath at 160°C with stirring for 5-10 min to fully dissolve NaCl and NaBr to obtain liquid A. Ag is added to ethylene glycol and stirred and dissolved in the dark for 20 min to obtain liquid B after full dissolution. Liquid A is added to a reaction vessel and sealed, and nitrogen is introduced into the vessel to remove oxygen in the system, and the vessel is placed in an oil bath and heated to 160°C with stirring. Liquid B is slowly added dropwise using a syringe, and liquid B is kept in the dark during this process. After the addition is completed, stirring is continued for 2 min, and stirring is turned off. The reaction is allowed to stand at 160°C for 1.5 h, obtaining a dispersion of silver nanowires; wherein the mass ratio of NaCl to NaBr is 2:1, and the concentration of NaCl in liquid A is 0.1-0.5 mg·mL-1; liquid B is a 10 mg·mL-1 ethylene glycol solution of AgNO3; and the volume ratio of liquid A to liquid B is 2:1; After the silver nanowire solution is cooled to room temperature, acetone of 1-2 times the volume of the solution is added to the solution, and the mixture is shaken to mix. After the solution is obviously separated, the mixed solution is centrifuged, and the lower precipitate is retained. Anhydrous ethanol is added to shake and dissolve thoroughly. After the solution has no obvious solid precipitation, the solution is centrifuged, and the lower precipitate is retained. Anhydrous ethanol is added to shake and dissolve thoroughly. After the solution has no obvious solid precipitation, the solution is centrifuged, and the lower precipitate is retained. Deionized water is added to shake and dissolve thoroughly. After the solution has no obvious solid precipitation, the solution is centrifuged, and the lower precipitate is retained. Deionized water is added to shake and dissolve thoroughly. After the solution has no obvious solid precipitation, the solution is centrifuged, and the lower precipitate is retained; the precipitate is evenly dispersed in a dispersant and stored in a dark place to obtain a dispersion of silver nanowires; wherein the centrifugal speed is 6000-8000 r·min-1, and the centrifugal time is 3-5 min; the dispersant is anhydrous ethanol and deionized water; Step 4: Preparation of silver nanowire / zinc oxide array structure composite transparent conductive film The ZnO nanotree array structure film prepared in step 2 is spin-coated by a spin coating method, and the dispersion of silver nanowires is spin-coated on the ZnO nanotree array structure film to obtain a single-layer silver nanowire / zinc oxide array structure composite transparent conductive film, and then the dispersion of silver nanowires is repeatedly spin-coated on the single-layer silver nanowire / zinc oxide array structure composite transparent conductive film to obtain the silver nanowire / zinc oxide array structure composite transparent conductive film.

2. The preparation method according to claim 1, characterized in that: The spin coating method specifically comprises: (a) First, the ZnO nanotree array structure film prepared in step 2 is fixed in a desktop coating machine by vacuuming with an oil pump, and the rotation speed is adjusted to 1000-4000 r·min-1. 50-100 μL of 10 mg·mL-1 silver nanowire dispersion prepared in step 3 is dripped on the surface during the rotation of the ZnO nanotree array structure film, and the film is rotated for 10-60 seconds after the dripping is completed; (b) The film material is then removed from the benchtop coating machine and placed under an infrared lamp to dry for 3-5 min; (c) After the single-layer silver nanowire / zinc oxide array structure composite transparent conductive film is dried, repeat 1-5 times at a rotation speed of 1000-4000 r·min-1, take 50-100 μL of 10 mg·mL-1 silver nanowire dispersion prepared in step 3 and drop it on the surface during the rotation of the single-layer silver nanowire / zinc oxide array structure composite transparent conductive film, continue to rotate for 10-60 s after the addition is completed, and then place it under an infrared lamp to dry for 3-5 min; (d) The obtained silver nanowire / zinc oxide array structure composite transparent conductive film has a mass of 0.01-5 mg per square centimeter of silver nanowires, which is composited with the ZnO nanotree array structure film by 1-6 repeated spin coating.

3. A silver nanowire / zinc oxide array structure composite transparent conductive film prepared by the method according to claim 1.

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