Theoretical Analysis of Spectral Selective Transmission Coatings for Solar Energy PV System

Spectral selective transmission coatings can adjust the spectrum of incident solar radiation to reduce the waste heat generation in solar cells and to improve solar photovoltaic conversion efficiency. The ideal spectral transmissivity of the coatings should match the spectral response of solar cells, which means the ideal spectral transmissivity should be equal to 1.0 in the range of the spectral response and 0 in the other spectrum. The reflection performance of the three kinds of spectral selective transmission coatings for silicon solar cells are designed and analyzed. The results indicated that the ZnS/Na3AlF6 coating systems have a wider reflected infrared (IR) region than the TiO2/SiO2 coating systems, but lower transmissivity in the wavelength range of 0.5 mu m to 1.1 mu m. Furthermore, an Nb2O3/SiO2 coating system is proposed and optimized, which has 31 layers with a smaller total thickness of 2.675 mu m. The radiative properties including reflectivity and transmissivity of spectral selective transmission coatings are investigated and theoretically analyzed.