Research on the Influence of the Interfacial Properties Between a Cu<sub>3</sub>BiS<sub>3</sub> Film and an In<i><sub>x</sub></i>Cd<sub>1−</sub><i><sub>x</sub></i>S Buffer Layer for Photoelectrochemical Water Splitting
Xiaomin Wu, Weidong Zhao, Yucheng Hu, Guohong Xiao, Huanyang Ni, Shigeru Ikeda, Yun Hau Ng, Feng Jiang
Abstract
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.