Ultrabright and Stable Red Perovskite Nanocrystals in Micro Light‐Emitting Diodes Using Flow Chemistry System

Abstract Addressing the challenges of the efficiency and stability of red perovskite nanocrystals is imperative for the successful deployment of these materials in displays and lighting applications. the structural dynamic changes of red perovskite quantum dots (PQDs) are explored using a flow chemistry system to solve the above hurdles. First, the ultrabright red‐emitting PQDs of CsPb(Br,I) ₃ are achieved by adjusting ligand distribution (oleic acid and oleyamine) in combination with different flow rates and equivalence ratios. The PQDs exhibit an impressive photoluminescence quantum yield (PLQY) of 95%. In addition, as mentioned in numerous previous studies, the severe instability of mixed halide perovskites is due to halide immigration. Therefore, in this paper, zinc, which has a lower dissociation energy than lead is utilized, as a reagent to provide more halide ions in the synthesis to enhance the stability of PQDs. As a result, a CsPb(Br,I) ₃ @Cs ₄ Pb(Br,I) ₆ core‐shell structure with outstanding stability and 92% PLQY is obtained. The simple method for synthesizing the core‐shell structure of CsPb(Br,I) ₃ @Cs ₄ Pb(Br,I) ₆ paves the way for the production of perovskite micro light‐emitting diodes for commercial applications.