Cu2ZnSn(S,Se)4 solar cells based on chemical bath deposited precursors

• A chemical bath deposition method is developed to prepare Cu2ZnSn(S,Se)4 thin films.
• The Cu2ZnSn(S,Se)4 thin films show good crystallization.
• Solar cells with efficiencies up to 4.5% can be prepared based on the Cu2ZnSn(S,Se)4 layer.
• The limiting factors for the solar cell efficiency are analyzed.

A low-cost method has been developed to fabricate Cu2ZnSn(S,Se)4 solar cells. By this method, firstly SnS, CuS, and ZnS layers are successively deposited on a molybdenum/soda lime glass (Mo/SLG) substrate by chemical bath deposition. The Cu2ZnSn(S,Se)4 thin films are obtained by annealing the precursor in a selenium atmosphere utilizing a graphite box in the furnace. The obtained Cu2ZnSn(S,Se)4 thin films show large crystalline grains. By optimizing the preparation process, Cu2ZnSn(S,Se)4 solar cells with efficiencies up to 4.5% are obtained. The results imply that the Cu2ZnSn(S,Se)4/CdS interface and the back contact may be limiting factors for solar cell efficiency.