Shape-controlled synthesis of CsPbBr3 nanorods with bright pure blue emission and high stability

Abstract

Metal halide perovskite nanocrystals (NCs) have emerged as highly promising luminescent materials for next generation light-emitting diodes (LEDs). However, pure blue perovskite LEDs (460–470 nm) suffer from issues such as unstable color, multi-peak profile, and poor photoluminescence quantum yield. Herein, CsPbBr₃ nanorods (NRs) with pure blue light emission and uniform morphology are achieved by precisely controlling the synthesis conditions. Our CsPbBr₃ NRs show a high PLQY of 62.65% and color purity with single peak emission at 462 nm. Through optimizing the ratio of ethyl acetate and isopropanol to purify CsPbBr₃ NRs and remove redundant ligands, CsPbBr₃ NRs also show long-term stability. The single blue emission of the obtained CsPbBr₃ NR solution is maintained even after 120 days when dispersed in n-hexane under ambient conditions. Under humidity of ∼45%, the corresponding solid perovskite films show blue light emission for over 20 days under air conditions. As a result, the devices exhibit a pure electroluminescence (EL) spectrum at 455 nm for perovskite light-emitting diodes (PeLEDs). The high photoluminescence and stability may evoke more inspiration for achieving long-term stability and highly efficient pure blue PeLEDs.