Extra-large photocurrent in acceptor-donor co-doped single-layer BiVO4 film

The novel photovoltaic effect mechanism has been consistently corroborated over the last decade, however, the low photocurrent density remains a significant impediment to its practical applications. In this study, an extra-large photocurrent density is achieved in the acceptor (A 2+ , A = Ca, Sr, Ba)-donor (W 6+ ) co-doped BiVO 4 (BVO) films prepared with a sol-gel method. A photocurrent density of 4.05 mA/cm 2 under 450 nm light illumination and a large detection rate of 8.4 × 10 11 Jones and 5.4 × 10 11 Jones for 365 nm and 450 nm are respectively obtained. The high photoelectric conversion efficiency (PCE) of 2.4 % is obtained in the Au/BVO/Pt sandwich structure under 365 nm (10 mW/cm 2 ) light illumination using Sr 2+ -W 6+ co-doped film, even if the light is obstructed by Au top electrode. A possible mechanism based on uneven composition formed by acceptor-donor ions is proposed to explain the enhancement of the photovoltaic effect in A 2+ -W 6+ co-doped BVO films. The composite ion doping engineering presents a novel strategy for improving the photoelectric conversion efficiency in single-layer films.