Research on the Influence of the Interfacial Properties Between a Cu3BiS3 Film and an InxCd1−xS Buffer Layer for Photoelectrochemical Water Splitting

Abstract The ternary compound photovoltaic semiconductor Cu 3 BiS 3 thin film‐based photoelectrode demonstrates a quite promising potential for photoelectrochemical hydrogen evolution. The presented high onset potential of 0.9 V RHE attracts much attention and shows that the Cu 3 BiS 3 thin films are quite good as an efficient solar water splitting photoelectrode. However, the CdS buffer does not fit the Cu 3 BiS 3 thin film: the conduction band offset between CdS and Cu 3 BiS 3 reaches 0.7 eV, and such a high conduction band offset (CBO) significantly increases the interfacial recombination ratio and is the main reason for the relatively low photocurrent of the Cu 3 BiS 3 /CdS photoelectrode. In this study, the In x Cd 1− x S buffer layer is found to be significantly lowered the CBO of CBS/buffer and that the In incorporation ratio of the buffer influences the CBO value of the CBS/buffer. The Pt‐TiO 2 /In 0.6 Cd 0.4 S/Cu 3 BiS 3 photocathode exhibits an appreciable photocurrent density of ≈12.20 mA cm −2 at 0 V RHE with onset potential of more than 0.9 V RHE , and the ABPE of the Cu 3 BiS 3 ‐based photocathode reaches the highest value of 3.13%. By application of the In 0.6 Cd 0.4 S buffer, the Cu 3 BiS 3 ‐BiVO 4 tandem cell presents a stable and excellent unbiased STH of 2.57% for over 100 h.