Band alignments at interface of ZnO/FAPbI3 heterojunction by X-ray photoelectron spectroscopy

The band alignments at the interface of ZnO/HC(NH2)2PbI3 (FAPbI3) heterojunction were measured by X-ray photoelectron spectroscopy. Core levels of Pb 5d and Zn 3d were utilized to align the valence-band offset (VBO). The VBO was determined to be 1.86 ± 0.30 eV, and the conduction-band offset (CBO) was concluded to be 0.05 ± 0.30 eV, manifesting that the ZnO/FAPbI3 heterojunction has a type-I band alignment. The data of the band alignment of ZnO/FAPbI3 heterojunction may benefit the design and development of novel perovskite solar cells (PSCs).