Unusual electric field-induced optical behaviors in cesium lead bromide perovskites

Abstract

The electric field effect on the optical properties of semiconductors is important in terms of both fundamental physics and technological applications. Here, we explored the optical behavior of cesium halide perovskites under a varied electric field (F). We revealed the intrinsically distinct photoluminescence (PL) spectral evolution between the quantum-confined perovskites and the bulk phase, indicating the different carrier recombination behaviors under F. Strong PL quenching along with significant broadening of emission linewidths was observed. Notably, the CsPbBr3 colloidal quantum dots and nanoplatelets exhibit an unusual field-induced bandgap increase, which is attributed to the weakened orbital coupling between the Pb 6s and Br 4p states with the increase in F. These results could advance their application potential in optoelectronics.