Random inverted pyramid textured polydimethylsiloxane radiative cooling emitter for the heat dissipation of silicon solar cells

Radiative cooling is a promising passive cooling phenomenon. For the heat dissipation of silicon solar cells, radiative cooling emitters require high transmittance in the wavelength range of 300–1100 nm and high emissivity in the range of 8–13 μm. In this paper, a simple and low-cost coating and embossing process is proposed to texture the surface morphology of the PDMS film. A radiative cooling emitter is prepared with a random inverted pyramid-like light-trapping structure on the surface. The experimental results show that the transparency and radiative cooling performance of textured polydimethylsiloxane films are improved by 2.1% and 2.7%, respectively. When using a polished Al mirror as the substrate, the radiative cooling temperature difference and net radiative cooling power are increased to 12.8 ℃ and 103 W·m−2, respectively. By employing it as a solar cell radiator, the radiative heat dissipation power of the solar cell is increased by 67 W·m−2, and the working temperature is reduced by over 17 ℃. An improvement in photoelectric conversion efficiency of 1.02% is achieved. It is demonstrated that the texturing treatment also improves the hydrophobicity of the polydimethylsiloxane film. The film is more applicable for radiative cooling emitters that are directly exposed to the atmosphere in outdoor environments.