2D/3D heterojunction carrier dynamics and interface evolution for efficient inverted perovskite solar cells

Abstract

The 2D/3D heterojunction perovskites have garnered increasing attention due to their exceptional moisture and thermal stability. However, few works have paid attention to the influence of the subsequent change process of 2D/3D heterojunction PSC on the stability of PSCs. Moreover, the evolution of the interface and carrier dynamic behavior of the 2D/3D perovskite films with long-term operation has not been systematically developed before. In this work, the effects of 2D/3D heterojunction evolution on the interface of perovskite films and different carrier dynamics during 2D/3D evolution are systematically analyzed for the first time. The decomposition of 2D/3D heterojunction in the perovskite film will have a certain impact on the surface and carrier dynamics behavior of perovskite. During the evolution of 2D/3D heterojunction, PbI₂ crystals will appear, which will improve the interfacial energy level matching between the electron transport layer and perovskite film. With a long evolution time, some holes will appear on the surface of perovskite film. The open circuit voltage (V_OC) of PSCs increased from 1.14 to 1.18 V and the PCE increased to 23.21% after 300 h storage in the nitrogen atmosphere, and maintained 89% initial performance for with 3000 h stability test in N₂ box. This discovery has a significant role in promoting the development of inverted heterojunction PSCs and constructing the revolution mechanism of charge carrier dynamic.