Stable Bismuth-Doped Lead Halide Perovskite Core-Shell Nanocrystals by Surface Segregation Effect.

Lead halide perovskite nanocrystals (NCs) exhibit excellent optoelectronic performance, however, the broad application is limited by their poor stability. Herein, a strategy for stable core-shell structured bismuth-doped lead halide perovskite NCs is reported. The stable core-shell perovskite NCs are prepared based on heterovalent substitutions and surface segregation effect. Core-shell features are revealed through advanced characterization and structure analyses. Meanwhile, the transfer of carriers between the core and the shell is observed by ultrafast transient absorption spectroscopy. The core-shell structured perovskite NCs exhibit outstanding structure stability and retain 97% of the original photocatalytic efficiency after cycle experiments under moisture ambient and light irradiation. Such a core-shell structure constructs gradient energy levels. These findings are expected to facilitate the development of stable lead halide perovskite devices.