Research Progress of Multifunctional Coatings for Solar Panels

Fossil fuels are the most widely used and used fuels in the world. The large-scale use of fossil fuels has a great impact on the earth's environment, such as global warming and acid rain. Faced with this severe situation, scientists around the world have launched research on renewable energy and green energy technologies. Solar energy is widely studied as the most important renewable energy and green energy. Solar panels, as the conversion equipment of solar energy, have aroused great interest of scientists. Solar energy is available all year round. It provides 5.0 x 1024 J of energy per year, which is 10,000 times the world's actual annual energy consumption. Some of the energy can be effectively used for power generation. However, due to the reflection of air/glass interface and the accumulation of dust on solar panels, most of the energy incident on solar energy will be lost. To this end, researchers in various countries use multi-functional films or coatings to improve the surface morphology and characteristics of solar panels, in order to enhance their self-cleaning, anti-reflection, anti-fog and energy transmission performance. In the preparation of solar panel coating, a variety of materials and methods have been used, including superhydrophobic, superhydrophilic and photoactive coatings. In this paper, the preparation and properties of solar panel coatings are reviewed, including surface morphology, wettability, conductivity and light transmittance. The basic concepts of self-cleaning (i.e. superhydrophobicity, superhydrophilicity) and anti-reflection (i.e. transparency) properties are discussed. Then the latest methods and technologies for preparing superhydrophobic, superhydrophilic, photoactive and transparent films are introduced. In the coatings of solar panels, the application and research progress of self-cleaning, dust-proof and antireflective coatings in solar cell modules are mainly introduced. Finally, advanced coatings with hybrid functions such as self-healing and anti-bacterial activity are introduced. These coatings show a new progress in solar panel coatings, because they combine various properties, can significantly improve the transparency, wettability, anti-fouling and self-cleaning of glass substrates, and provide other functions, such as self-healing and anti-bacterial activity.