Design and Fabrication of Bi2O3/BiFeO3 Heterojunction Film with Improved Photoelectrochemical Performance

Abstract In this work, high-quality BiFeO3 (BFO), Bi2O3, Bi2O3/BFO films on indium tin oxide (ITO) substrates were prepared by pulse laser deposition (PLD). Photoelectrochemical measurements were carried out to determine their potential as photoelectrodes for photoelectrochemical water splitting. The photocurrent of Bi2O3 /BFO heterojunction film was found to be twice higher than that of pure BFO film, and the onset potential was positively shifted by 240 mV. To understand the mechanism of such improved performance, detailed characterization and analysis of the band alignment and charge-carrier dynamics for all of the samples were carried out. A type II junction was formed at the interface between Bi2O3 and BFO for the heterojunction film, which resulted in the promoted electron-hole separation process under AM 1.5G light simulation. The present study suggests that Bi2O3/BFO type II junction film with superior photoelectrochemical response could be applied for designing and fabricating high-performance photoelectrochemical cells.