On the Role of CsPbBr Phase in the Luminescence Performance of Bright CsPbBr Nanocrystals.

CsPbBr nanocrystals have been identified as a highly promising material for various optoelectronic applications. However, they tend to coexist with CsPbBr phase when the reaction conditions are not controlled carefully. It is therefore imperative to understand how the presence of this phase affects the luminescence performance of CsPbBr nanocrystals We synthesized a mixed CsPbBr-CsPbBr sample, and compared its photo- and radioluminescence properties, including timing characteristics, to the performance of pure CsPbBr nanocrystals. The possibility of energy transfer between the two phases was also explored. We demonstrated that the presence of CsPbBr causes significant drop in radioluminescence intensity of CsPbBr nanocrystals, which can limit possible future applications of CsPbBr-CsPbBr mixtures or composites as scintillation detectors.