Photoluminescence-Raman/FTIR under Variable Hydrostatic Pressure to Reveal the Origin of Luminescent Centers in Lead Halide Perovskites

Organic-inorganic lead halide perovskites have provided us not only a long-awaited material platform to realize the dream of high-efficiency solar cells and many other optoelectronic devices, but also a wide range of structures to explore unusual fundamental sciences. Because of their extremely high quantum efficiency, light-emitting diodes (LEDs) and lasers are becoming important applications of perovskites. Among them, several low-dimensional perovskites or related materials have attracted more attention due to either controversial luminescence mechanism or peculiar edge emission. In this talk, I will first discuss these controversies and challenges to resolve them, I will then introduce our recently developed techniques to resolve the controversies and identify the origin of luminescent centers. Specifically, same-spot photoluminescence (PL) -Raman/IR is firstly used as an effective strategy to correlate PL to the structure in a direct one-to-one relationship, pressure-dependent PL-Raman is then developed as a dynamic probe to excludes point defects as a possible mechanism.