Construction of efficient and stable CsPbBr3 nanocrystals via calcium and fluorine ion combined-treatment for light-emitting diodes

Perovskite nanocrystals, which are well-known for their outstanding optoelectronic properties, have attracted widespread attention for several photonic and optoelectronic technologies. However, the inherent instability of perovskite nanocrystals limits their practical applications. Therefore, herein, we developed a calcium- and fluorine-ion combined-treatment method to enhance the stability of perovskite nanocrystals, which not only exhibited near unity photoluminescence efficiency and cubic morphology, but also possessed excellent photostability and thermal resistance. Additionally, the light-emitting diodes incorporating these perovskite nanocrystals showed pure green electroluminescence with a maximum external quantum efficiency of 11.85%, luminance as high as 20 940 cd m−2, and stable operation for up to 172 min.