Comparative investigation on temperature-dependent photoluminescence of CH3NH3PbBr3 and CH(NH2)2PbBr3 microstructures

Abstract

Organic–inorganic lead bromide perovskite is regarded as a highly efficient material for green light devices. In this study, we report on the fabrication of CH₃NH₃PbBr₃ and CH(NH₂)₂PbBr₃ perovskite microstructures. The morphologies and crystal structures of these two types of perovskite nanostructures are characterized and the differences in their photoluminescence behaviour are demonstrated. The temperature-dependent photoluminescence of the CH₃NH₃PbBr₃ microstructure shows that exciton emission shifts continuously with increasing temperature and a trapped charge-carrier emission peak appears in the temperature region from 115 K to room temperature. Temperature-dependent photoluminescence of CH(NH₂)₂PbBr₃ reveals a blue shift of the exciton emission with increasing in temperature, but there is a sudden red shift near 150 K due to phase transition. Temperature coefficients of the band gaps and exciton thermal activation energies of CH₃NH₃PbBr₃ and CH(NH₂)₂PbBr₃ microstructures are calculated. At room temperature, the exciton thermal activation energy of CH₃NH₃PbBr₃ is higher than that of CH(NH₂)₂PbBr₃, which indicates the excitons in CH₃NH₃PbBr₃ are more stable.