8% Efficient Cu 2 ZnSn(S,Se) 4 Solar Cells from Redox Equilibrated Simple Precursors in DMSO

8.3% efficient Cu2ZnSn(S,Se)4 solar cells are demonstrated from an absorber film processed from molecular precursor solution of simple salts, thiourea, and dimethyl sulf­oxide (DMSO). Characterizations of the absorber film and devices reveal a pure kesterite absorber material with imperfect morphology, which suggests great potential for further improvement in device performance.