Water-resistant, monodispersed and stably luminescent CsPbBr 3 /CsPb 2 Br 5 core–shell-like structure lead halide perovskite nanocrystals

Abstract Lead halide perovskite materials are thriving in optoelectronic applications due to their excellent properties, while their instability due to the fact that they are easily hydrolyzed is still a bottleneck for their potential application. In this work, water-resistant, monodispersed and stably luminescent cesium lead bromine perovskite nanocrystals coated with CsPb 2 Br 5 were obtained using a modified non-stoichiometric solution-phase method. CsPb 2 Br 5 2D layers were coated on the surface of CsPbBr 3 nanocrystals and formed a core–shell-like structure in the synthetic processes. The stability of the luminescence of the CsPbBr 3 nanocrystals in water and ethanol atmosphere was greatly enhanced by the photoluminescence-inactive CsPb 2 Br 5 coating with a wide bandgap. The water-stable enhanced nanocrystals are suitable for long-term stable optoelectronic applications in the atmosphere.