A sandwich-like structural model revealed for quasi-2D perovskite films dagger

Abstract

The excellent performance and stability of perovskite solar cells (PSCs) based on quasi-2D Ruddlesden-Popper perovskites (RPPs) holds promise for their commercialization. Further improvement in the performance of 2D PSCs requires a detailed understanding of the microstructure of the quasi-2D perovskite films. Based on scanning transmission electron microscopy (STEM), time-resolved photoluminescence, and transient absorption measurements, a new sandwich-like structural model is proposed to describe the phase distribution of RPPs. In contrast to the conventional gradient distribution, it is found that small-nRPPs are sandwiched between large-nRPP phase layers at the front and back sides owing ..