Preparation of surface modified CsPbBr3@CsPb2Br5 nanocrystals with high stability by a pseudo-peritectic method

Lead halide perovskite CsPbBr 3 nanocrystals (NCs) have attracted great interest in recent years owing to their excellent properties such as strong light absorption , high photoluminescence quantum yield (PLQY), good wavelength tunability, and narrow FWHM. However, their instability is still a bottleneck for their potential application. In this work, a pseudo-peritectic method, which is a peritectic reaction in solutions, was proposed. The phenomenon of “Survival of the fittest” was observed. The synthesized CsPb 2 Br 5 phase greatly reduces the surface defects , and improves the stability and PL properties. The pseudo-peritectic method using for preparing surface modified CsPbBr 3 @CsPb 2 Br 5 nanocrystals is a significant pathway to achieve long-term stable lead halide perovskite for optoelectronic devices .