Full-Spectrum Solar Energy Utilization and Enhanced Solar Energy Harvesting via Photon Anti-Reflection and Scattering Performance Using Nanophotonic Structure
Huaxu Liang, Fuqiang Wang, Ziming Cheng, Chao Xu, Guiqiang Li, Yong Shuai
Abstract
Conventional Si photovoltaic cells cannot convert full solar energy spectrum (400~2 500 nm) into electricity owing to the mismatch between Si band gap and broad range of solar photon energies. Transparent silicon PV cell allows sunlight in the wavelength of 1 100~2 500 nm to transmit through itself and irradiate on the thermal absorber below. The traditional photon management method based on texturing silicon layer with nanostructures can enhance 400~1 100 nm absorptivity and 1 1002 500 nm transmittance of transparent silicon PV cell. However, an increase in charge carrier capture and a decrease in electricity generation efficiency are often observed with this. In this study, a novel spectral splitting method based on frontlocated wavelength-sized TiO 2 biomimetic moth-eye nanophotonic structure is put forward, which can inhibit the increase of charge carrier capture and recombination. The biomimetic moth-eye nanophotonic structure was optimized by using finitedifference time-domain (FDTD) method to achieve excellent photon anti-reflection and scattering properties. The calculation results indicated that the absorption factor and transmission factor of transparent silicon PV cell could be increased from 46% to 58% and from 11% to 14%; the relative power conversion efficiency enhancement rate and relative incident radiation power enhancement rate was 32% and 27% when the TiO 2 biomimetic moth-eye was adopted.