Manipulating the Photoluminescence and Carrier Characteristics of Excited FAPbBr3 Nanocrystals with Pressure

Halide perovskite nanocrystals (NCs) have great potential in the field of optoelectronics, owing to their excellent photophysical characteristics. Herein, the photoluminescence (PL) characteristics (involving the PL quantum yield (QY) and radiative lifetime) and carrier dynamics of FAPbBr3 NCs have been further investigated by applying the pressure. Pressure-dependent steady spectral data confirm that FAPbBr3 NCs pass through a cubic Pm3̅m, a cubic supercell Im3̅, and an orthorhombic Pnma in turn. The deep defect and the phase change originated from pressure can decrease the PL QY, prolong the radiative lifetime, and effectively manipulate the carrier dynamics involving the carriers captured by defects and free carriers. Pm3̅m owns excellent properties of PL and carriers, which is suitable for displaying devices, but Pnma can restrict photon emission and carrier capture, which has potential in photovoltaic devices. These results allow us to advance the practical application of this material in the future.