Study on improving the efficiency of crystalline silicon photovoltaic module with down-conversion chlorophyll film

Crystalline silicon (c-Si) solar cells cannot make full use of solar energy at present, especially the short wavelength (300–500 nm) energy. Owing to the inherent problem, c-Si photovoltaic (PV) modules are still facing the trouble of low PV conversion efficiency. Applying spectral down-conversion (DC) materials to transform underutilized solar spectrum is an effective way to improve the problem. In this study, inspired by chlorophyll (Chl) fluorescence phenomenon, Chl film were specially prepared by encapsulating Chl with oxygen insulating material as spectral DC material. Then, to enhance Chl stability, nano SiO2 was added to the film-forming solution. The spectroscopic properties of the Chl films were analyzed, and the output power characteristics of the PV modules coated with the Chl films were inspected. The experimental results indicate that the prepared Chl film has good spectral conversion performance, and can convert light of about 400 nm into about 670–680 nm which is suitable for PV modules. After being exposed outdoors for about 30 days, the maximum power of the PV module coated by the Chl film with SiO2 is still improved by 9.2%. Since the Chl can be obtained from nature by an economical way, the Chl film is a promising material to improve the power generation efficiency of c-Si PV modules.