Durable and multifunctional coating design with superhydrophobicity, high transparency, radiative cooling for photovoltaic application

The market-dominant silicon-based solar cells are facing great challenges in further improving their benchmark efficiency. However, due to dust deposition and temperature rise, the actual operating efficiency is still far from the benchmark efficiency. The goal of this study is to develop a durable and multifunctional coating with superhydrophobicity, high light transmittance and strong infrared radiation, which is applied to the surface of photovoltaic glass to reduce dust deposition and lower the module temperature. Based on a silicon wafer template and die casting process, epoxy resin microcavities are prepared on the glass surface, and SiO₂ nanoparticles are sprayed into the microcavities to complete the preparation of the multifunctional coating. The experimental test results show that the coating has a contact angle of about 160°, a visible transmittance over 91 %, and an infrared emissivity of 94.5 % among the atmospheric window, demonstrating the potential of self-cleaning and radiative cooling functions. The coating also shows good durability through sandpaper wear, scraper wear, tape peeling, and water jet tests. The multifunctional coating developed in this study is expected to be applied to different types of photovoltaic cells to improve their photoelectric conversion efficiency in outdoor environments.