Stable and highly efficient blue-emitting CsPbBr3 perovskite nanomaterials via kinetic-controlled growth

Compared to the classical II-VI quantum dots (QDs), the reaction kinetics of cesium lead halide perovskite nanocrystals (NCs) are not clear yet because of the fast reaction rate. Here, an Ag+-assisted slow-release strategy is proposed to synthesize CsPbBr3 nanomaterials, where the reaction rate is decreased and the reaction time is prolonged to days. It is found that the Ag+ ions can bind with the PbBr2 precursor, which makes the formation of PbBr64- as the rate-limiting step. Shape conversion from dots to nanowires and then to platelets has been observed for the CsPbBr3. Pure blue-emitting nanoplatelets (NPLs) with near unity photoluminescence quantum yield (QY) are acquired. In addition, the blue-emitting CsPbBr3 solution is very stable, which has been stored for over 1.5 years without performance degradation. A liquid light-emitting diode (LED) prototype is further fabricated and exhibits excellent stability towards driving currents.