Influence of [Cu]/[Cu+Sn] molar ratios in p-type Cu-Sn-S photoelectrodes on their photoelectrochemical performances in water and salt-water solutions

Ternary copper-tin-sulfide thin films are prepared on various substrates by using the sulfurization of co-sputtering Cu-Sn metal precursors. The effect of the [Cu]/[Cu+Sn] molar ratio in samples on the structural and photoelectrochemical performances of Cu-Sn-S samples in various electrolytes is examined. The maximum photoelectrochemical performances of the samples in 0.5 M K2SO4 and 1 M NaCl aqueous solutions are 0.55 and 0.34 mA/cm2 at an external potential of −1.2 V versus an Ag/AgCl reference electrode under light illumination with the light intensity of 100 mW/cm2, respectively.92