Solution-processed Bi <sub>2</sub> S <sub>3</sub> /BiVO <sub>4</sub> /TiO <sub>2</sub> ternary heterojunction photoanode with enhanced photoelectrochemical performance
Xinli Li, Sha Wang, Yingde Wang, Jiachen Yang, Kexuan Wang, Chao Han, Lihua Li, Renhong Yu, Yong Zhang
Abstract
Abstract TiO 2 is an important component of photoelectric devices. How to broaden the light absorption of TiO 2 and accelerate the separation of photo-generated electrons and holes is the focus of the current research. Building heterojunction with narrow band gap semiconductor and TiO 2 is one of the important measures to improve its photoelectric performance. We prepared BiVO 4 /TiO 2 binary heterojunction by the simple hydrothermal method and analyzed the effect of BiVO 4 precursor solution concentration on the microstructure and photoelectric performance of the heterojunction. BiVO 4 /TiO 2 binary heterojunction can effectively improve the photoelectric performance of TiO 2 , and the transient current density reaches 85 μA/cm 2 . To further boost the photocurrent of BiVO 4 /TiO 2 , Bi 2 S 3 was in situ grown on the heterojunction to form Bi 2 S 3 /BiVO 4 /TiO 2 ternary heterojunction. The results show that the band gap of Bi 2 S 3 /BiVO 4 /TiO 2 composites is significantly narrowed compared with that of TiO 2 . The light absorption has been expanded to the visible range, and the photogenerated current density is also greatly boosted (0.514 mA/cm 2 ). This Bi 2 S 3 /BiVO 4 /TiO 2 ternary heterojunction accelerates the separation of photo-carriers and improves the photoelectric performance of the device. The possible transport mechanism of photo-carriers in ternary heterojunction is analyzed. The current study provides an effective strategy for in situ construction of novel multicomponent heterojunction and provides a basis for the application of Bi 2 S 3 /BiVO 4 /TiO 2 in the optoelectronic field.