Highly Luminescent and Stable Halide Perovskite Nanocrystals

Lead halide perovskites are potential candidates for wide-color-gamut display applications. Recently, red and green light-emitting diodes (LEDs) based on these materials have achieved external quantum efficiency (EQE) of over 20%, while the blue devices lag behind them severely because of a much lower photoluminescence quantum yield (PL QY) and inferior stability. Blue perovskite nanocrystals (NCs) are promising active materials for high-efficiency devices; however, they are reported to exhibit low defect tolerance and suffer from troublesome ion migration behavior. Though some good ideas have been proposed to overcome these problems, the present results are still unsatisfactory. In this Perspective, diverse methods toward blue perovskite NCs are summarized, as well as the intrinsic origin of low stability and poor optical properties. Then, strategies to improve their performance and stability and critical challenges that severely limit the stability and performances of blue perovskite NCs are discussed. Perspectives of further developments on synthesis and applications of blue perovskite NCs are both provided.