Photoluminescence Quenching and Dynamics of FAPbBr ₃ Perovskite Nanocrystals With CuBr

Over the past decade, lead halide perovskites have shown an excellent promise for photovoltaic applications. To maximize their efficiency, understanding the electron/hole separation and transfer processes is crucial. A key focus is identifying effective hole acceptors; our research explores the hole acceptor ability of CuBr with various bromide‐based green‐emitting APbBr 3 (A = FA, MA, Cs) perovskite nanocrystals (NCs). We observed significant photoluminescence (PL) quenching and fast PL decay in the presence of CuBr, indicating a strong interaction between the two species. The energy levels of the NCs align with CuBr’s HOMO–LUMO levels, and ultrafast pump–probe experiments reveal quick hole transfer from photoexcited APbBr 3 NCs to CuBr, with time constants of 100 ps for FAPbBr 3 , 125 ps for CsPbBr 3 , and 176 ps for MAPbBr 3 NCs. This rapid hole extraction is attributed to the strong CuBr anchoring on the NCs surface, highlighting how a simple halide salt can enhance charge carrier transfer and advance the development of affordable solar cells.