Progress of interface engineering in perovskite solar cells

Organic-inorganic hybrid halide perovskite materials have been a suitable active layer in solar cells due to the extraordinary photonic and electronic properties. Perovskite solar cells (PSCs), no matter conventional structure or inverted structure, contain several key interfaces, including electrode/electron transport materials (ETM) interface, ETM/perovskite interface, perovskite/hole transport materials (HTM) interface, HTM/electrode interface. The interface is vital to the overall performance of the devices, since the exciton formation, dissociation, and recombination are directly related to the interface. Moreover, the degradation of devices is also highly sensitive to the interface. As a result, the deep understanding of the interfacial charge transfer and corresponding interfacial engineering is extremely important to achieve high-performance and high-stability PSCs. This review mainly focuses on the recent progress of interfacial engineering in PSCs, including conventional structured PSCs, PSCs employing carbon counter electrode, and inverted structured PSCs.