Anion exchange as an excellent tool to obtain highly efficient blue-emitting all-inorganic perovskite quantum dots

In this study, we examined the dynamic photoluminescence (PL) characteristics of all-inorganic perovskite quantum dots (QDs) during the anion-exchange process between bromide and chloride ions. CsPbBr3 QDs were synthesized using an ultrasound-induced hot-injection route. These QDs were then treated with TMS-Cl solutions, resulting in the formation of blue-emitting CsPb(Br/Cl)3 QDs with high quantum efficiencies. Even the addition of a small amount of TMS-Cl to the CsPbBr3 solution led to a noticeable blue shift of the emission. Moreover, surface treatment with a small amount of TMS-Cl also resulted in an enhanced PL quantum efficiency (PLQE) owing to surface trap removal. Exposure of the CsPbBr3 perovskite QDs solution to a higher amount of TMS-Cl yielded deep-blue-emitting QDs (412 nm) with a very high PLQE of 57 %.