"Solar energy is renewable and abundant enough to meet the growing energy demand, but its variability limits the application. Direct storage in the form of a clean fuel, like hydrogen, would solve this problem.Photoelectrochemical (PEC) cells employ solar energy to split water molecules producing H2 and O2. Thin films of Cu2ZnSnS4 (CZTS) and ZnCuInS2 (ZCIS) have shown remarkable efficiencies in ph ...