CsPbBr₃@CsPbBr_3- Cl Perovskite Core-Shell Heterojunction Nanowires via a Postsynthetic Method with HCl Gas

CsPbX₃ (X = Cl, Br, I) perovskite nanocrystals (NCs) are promising materials due to their excellent optoelectronic properties. This work shows a successful anion exchange reaction in CsPbBr₃ nanowire (NW) systems with HCl gas resulting in a blue-green light-emitting CsPbBr₃@CsPbBr_3- Cl core-shell heterojunction. By adjusting the reaction time and the reaction temperature, the structure and light emission of the NWs can be adjusted. The core-shell heterojunction NCs are stably luminescent in 24 h. The rational mechanism of anion exchange in perovskite NCs is also investigated. The work highlights the feasibility of NWs heterogeneously prepared under the HC1 gas atmosphere, which provides a new strategy for studying the two- and multicolor luminescent perovskite NCs.