A perovskite solar cell-TiO2@BiVO4 photoelectrochemical system for direct solar water splitting

Converting solar energy into hydrogen via photoelectrochemical water splitting has attracted significant attention during the past decades. Herein, we design a novel core/shell TiO2@BiVO4 photoanode in combination with a CH3NH3PbI3-based perovskite solar cell for unassisted solar water splitting. Compared to pristine TiO2 NRs, the resulting TiO2@BiVO4 film exhibits a 3.25-fold enhanced photocurrent density (∼1.3 mA cm−2) under irradiation (xenon lamp coupled with an AM 1.5 G filter, 100 mW cm−2). This significant enhancement is attributed to the excellent light absorption properties of BiVO4 and a fast electron transfer process in the single crystalline TiO2 NRs. Especially, the type-II band alignment between the BiVO4 and rutile TiO2 NRs provides a large driving force for electron injection from the BiVO4 to the TiO2. The perovskite solar cell-TiO2@BiVO4 photoelectrochemical tandem device exhibits an overall solar-to-hydrogen efficiency of 1.24%, comparable to other TiO2-based PV/PEC systems.