Controlled synthesis of SnSxSe2-x thin films for solar energy water splitting

Abstract

Earth-abundant and ecofriendly minerals SnSxSe2–x can be promising candidates for photoelectrochemical (PEC) cells because of their tunable band gaps and high absorption efficiency in the visible light range. In this paper, p type SnS thin films with sheet-like morphologies were successfully prepared by CBD method and then n-type SnSxSe2-x thin films were achieved by selenization annealing of SnS thin films. The physical properties and PEC performances of SnSxSe2-x thin films influenced by the annealing process were detailed studied. The photocurrent densities and stability of SnSxSe2-x films were further improved by the deposition of p-type CdS:Cu buffer layer. And the fabrication of FTO/SnSxSe2-x/CdS:Cu/TiO2/Pt photocathode improved the PEC performance further and the photocurrent as high as 10.5 mA/cm2 had been achieved. IPCE tests indicated that the FTO/SnSxSe2-x/CdS:Cu/TiO2/Pt structure achieved a power conversion efficiency of 31.3 %.