Efficiency improvement of Si solar cells by down-shifting Ce3+-doped and down-conversion Ce3+-Yb3+ co-doped YAG phosphors

Abstract

Down-shifting and down-conversion processes are an effective way to improve the poor response of single crystalline silicon (c-Si) solar cells at shorter wavelength region. The Ce3+-doped YAG possesses a down-shifting (DS) process which converts ultra-violet (UV) and blue light into yellow light whereas Ce3+-Yb3+ co-doped YAG exhibits a down-conversion (DC) process which converts UV and blue light into both yellow as well as near-infrared (NIR) light. In this paper, Ce3+-doped YAG and Ce3+-Yb3+ co-doped YAG phosphors are mixed with ethyl vinyl-acetate and then coated on the top surface of c-Si solar cells by using spin-coating method. The solar cells enhance the energy conversion efficiency from 15.71% to 16.06% (Δη = 2.23%) and 15.96% to 16.63% (Δη = 4.19%) for DS and DC process, respectively. The experimental results demonstrated that these types of phosphors are promising candidates for enhancing the performances of c-Si solar cells in practical application.