Bismuth ferrite (BFO), a p-type semiconductor with notable visible-light absorption, is an attractive photocathode material for photoelectrochemical (PEC) systems. This study presents a facile route to construct BFO/ZnO heterojunctions on fluorine-doped tin oxide (FTO) substrates via sol-gel and scraping method. A comprehensive characterization of the samples, including surface morphology, crystal structure, and chemical states, confirmed the successful fabrication of the BFO/ZnO heterojunction. The pure BFO exhibits photocathode behavior, with a negative photocurrent of -7.0 µA/cm², consistent with its p-type semiconductor characteristic. All heterojunction samples exhibited enhanced PEC performance, as demonstrated by the higher photocurrent densities. A maximum photocurrent density of -24.6 µA/cm² was detected in the optimal BFO/ZnO heterojunction sample, which was 3.51 folds by that of the pure BFO. The enhancement of PEC properties can be attributed to the built-in electric field ( E bif ) of the p-n junction, which can promote the separation and transfer efficiency of charge carriers, analyzed by the carrier dynamics and the well band alignment. This research offers a promising strategy for developing low-cost and efficient PEC conversion devices.
Shen et al. (Thu,) studied this question.