Thin film solar cells based on Ag-substituted CuSbS2 absorber

CuSbS 2 has been considered as a promising photovoltaic absorber material, due to its earth abundant and environmentally friendly constituents. However, the electron affinity and similar radius of cations bring heavy atomic disorders in CuSbS 2 film, limiting its photovoltaic performance. Herein, we report an efficient way to reduce disorders by introducing Ag atom into CuSbS 2 crystal structure. The crystal structure and chemical analysis confirm that Ag occupies the Cu position in the as-prepared films by the spray pyrolysis. The absorption spectra combined with photoluminescence measurement indicate that Ag-substituted CuSbS 2 films have fewer recombination centers. The density functional theory calculation result reveals that Ag-substituted CuSbS 2 has a more stable crystal structure, and the formation energy of the primary point defects obviously increases. Therefore, Ag-substituted CuSbS 2 photovoltaic device shows asignificantly improved power conversion efficiency from 0.73% to 2.48%.