Preparation And Performance Of Transparent Silicon Oxide-based Superhydrophobic Films For Anti-fouling Of Photovoltaic Modules

Since the discovery of the lotus leaf effect by the German botanists Barthlott and Neinhuis,superhydrophobic surfaces have attracted increasing interest in many fields,such as selfcleaning,drag reduction,anti-icing,corrosion protection and oil-water separation.Scientists have found that a rough surface structure and low surface energy are the two main factors necessary to achieve superhydrophobicity.Based on this principle,many methods for the preparation of superhydrophobic surfaces have been developed.In recent years solar energy has developed into the most popular source of renewable energy and photovoltaic modules themselves offer a relatively economical and efficient method of generating electricity.However,the efficiency of photovoltaic modules can be reduced by the build-up of dust on the panel surface and the dead space created by the shading effect of dust particles can lead to the "hot spot effect",which shortens the lifetime of the module.Therefore,it is of great importance to develop PV modules with anti-fouling properties.In this paper,the following research has been conducted on the preparation of transparent superhydrophobic films based on silicon oxide and their application to photovoltaic modules,with a view to solving the fouling problem on the surface of photovoltaic modules:(1)To analyze the basic principles of photovoltaic modules and the main output parameters of photovoltaic characteristics,to study the influence of light transmission on module output parameters and the constraints of photovoltaic power generation,to analyze the history and current status of research on dust deposition in photovoltaic modules,to introduce the relevant theories of superhydrophobic surfaces,to analyze the principles of transparent superhydrophobic coatings,and to introduce the preparation methods,applications and challenges of superhydrophobic surfaces;(2)To study the preparation methods of superhydrophobic films.The superhydrophobic coatings were prepared in a laboratory environment with glass as the substrate,silica particles as the filler material and the introduction of siloxane to reduce the surface energy in different ratios of the two.To study the microscopic morphology and surface components of the superhydrophobic films and to investigate the differences in wettability and light transmission between samples of different ratios;(3)To study the stability of each of the superhydrophobic films.This chapter investigates the mechanical properties,chemical stability,weathering resistance,UV resistance,thermal stability and self-cleaning properties of the coatings through various tests;(4)To investigate the effect of superhydrophobic films and glass substrates on the output characteristics of the modules.The effect of the superhydrophobic film cover on the PV module at different transmittance is first analyzed.Comparative experiments are then carried out,i.e.ash accumulation and simulated rainfall experiments are carried out on PV modules covered with superhydrophobic films and glass substrates,and then the output characteristics are tested in a solar generator,while the change in spectral performance is measured.As a result of the above experiments,the following conclusions were obtained:(1)The prepared superhydrophobic films have excellent hydrophobicity and transmittance.(1)After hydrophobic and spectral property studies,the superhydrophobic films have a water contact angle of 162° and a transmittance of 92.4%,compared to 27° and 89.9% for ordinary glass,increasing hydrophobicity and transparency after coating;(2)After stability testing and self-cleaning performance testing,the water contact angle of the superhydrophobic film is greater than 145°,which has excellent resistance to friction,corrosion,ageing,high and low temperatures.The superhydrophobic film has good selfcleaning properties,resulting in good anti-fouling performance of the module;(3)Superhydrophobic films can improve the output characteristics of PV modules and reduce dust accumulation.The PV output characteristics of super-hydrophobic films under dust accumulation show that the output power of PV modules covered by super-hydrophobic films is greater than that of glass-covered PV modules.The maximum power of the modules covered by the superhydrophobic film decreased by 1.8% compared to 8.6% for the blank glass-covered modules after dust accumulation and simulated rainfall tests.This study provides some ideas to reduce dust deposition on PV modules and improve the economics of PV plants.