Anti-Reflective superhydrophobic coatings with excellent durable and Self-cleaning properties for solar cells

Abstract

Photovoltaic modules are long-term exposed outdoors, and the surfaces are easily covered by dust, which seriously affects the power generation efficiency and increases the workload of maintenance. An anti-reflective and superhydrophobic coating with excellent durable and self-cleaning properties was proposed to improve this problem. The prepared coating has multiple structures to improve the durability. Firstly, the coating consists of a double-layer film structure, and the bottom layer is connected to the substrate through covalent bonding to improve the adhesion of the coatings; secondly, the hydrophobic silica particles in the top layer can be embedded in the pore structure of the bottom layer to improve the connection strength between the top and bottom layers; thirdly, hydrophobic silica particles in the top layer are fixed in a three-dimensional mesh structure formed by long-chain silica, which can improve the mechanical stability of the coatings. In addition, the preparation conditions of the hydrophobic particulate silica sols and the ratio of long-chain silica sol in the top layer solution can be adjusted to control the durable, anti-reflective, and superhydrophobic properties of the coatings. The experimental results indicate that the transmittance of the coated glass is increased by 5 % compared to the bare glass, and the coating has 6H pencil hardness test grade and 5B tape adhesion test grade. The maximum output power of the coated PV modules can be increased by 5.67 %. After simulating dust accumulation and rainfall, the power of coated and uncoated photovoltaic modules can be restored to 96.6 % and 83.0 % respectively, indicating that the prepared coating also has excellent self-cleaning ability.