The electronic structure of metal oxide/organo metal halide perovskite junctions in perovskite based solar cells

摘要

Cross-sections of a hole-conductor-free CH₃NH₃PbI₃ perovskite solar cell were characterized with Kelvin probe force microscopy. A depletion region width of about 45?nm was determined from the measured potential profiles at the interface between CH₃NH₃PbI₃ and nanocrystalline TiO₂, whereas a negligible depletion was measured at the CH₃NH₃PbI₃/Al₂O₃ interface. A complete solar cell can be realized with the CH₃NH₃PbI₃ that functions both as light harvester and hole conductor in combination with a metal oxide. The band diagrams were estimated from the measured potential profile at the interfaces, and are critical findings for a better understanding and further improvement of perovskite based solar cells.