Mixed-Dimensional Heterostructure of CsPbBr3 Nanocrystal and Bi2O2Se Nanosheet

Recently, semiconductor heterostructures comprising mixed-dimensional materials have attracted widespread attention due to their application in catalysis, photovoltaics, and optoelectronics. Here, we report the nano-heterostructure integration of CsPbBr3 nanocrystals (NCs) and ultrathin nanosheets (NSs) of Bi2O2Se to explore their optical properties. The formation of heterostructures was verified from the powder X-ray diffraction (PXRD) pattern and transmission electron microscopy (TEM) analysis, whereas the bonding interactions were studied using Fourier transform infrared (FTIR) spectroscopy. The photoluminescence (PL) quenching of CsPbBr3 NCs in the mixed-dimensional CsPbBr3@Bi2O2Se heterostructure was evidenced both at 298 and 77 K. Time-resolved PL was implemented to examine the charge transfer characteristics in these mixed-dimensional nano-heterostructures at both temperatures. PL quenching appeared as a result of the charge transfer from the conduction band of CsPbBr3 to Bi2O2Se via type-I electronic band alignment. The rate of charge transfer across the heterojunction was found to be relatively faster at 298 K than at 77 K.