Recent Advances in Energetics of Metal Halide Perovskite Interfaces

Metal halide perovskites, a class of crystalline semiconductors with unique optical and electronic properties, are emerging as potential solutions for low‐cost photovoltaics and photonic sources in fields of solar cells, sensors, light‐emitting diodes and lasers. Regardless of significant progress on device efficiency with the control over perovskite structures and film morphologies, unveiling the interface energetics and band alignment of these perovskite systems is indispensable for the performance optimization in the optoelectronic applications by grasping the photon harvest and charge transport processes. Herein we review the recent advances in the energetics of metal halide perovskite interfaces. The electronic properties of perovskite materials are addressed in terms of halide substitution, thermal annealing and substrate effects as well as trap states. The energy level alignments of interfaces between perovskite films and charge transport layers are then discussed, which is correlated to the photovoltaic properties in perovskite solar cells. Recent advances in energetics in metal halide perovskite interfaces are reviewed with a combined discussion of electronic structures of metal halide perovskites and energy level alignment at perovskite/organic heterointerfaces through photoemission spectroscopy techniques. The energetics at the perovskite interfaces with various carrier transport materials is highlighted, suggesting the impact on photocurrent generation process in perovskite solar cells.