Lead Halide Perovskite Cube Coupled Star Nanocrystal Photocatalysts

Ligand dynamics on the surface of nanocrystals plays a major role in controlling their successive layers growth. This has been widely established for chalcogenide nanomaterials but less explored for recently emerged halide perovskite nanocrystals. However, with the introduction of different non-lead metal (Cd and Mn) acetates/oxides to limit surface halide concentration and alkylammonium ion ligands, herein, star shaped cube coupled nanocrystals are reported, and their growth from less than 50 nm to nearly 500 nm is monitored. These acetates/oxides helped in inducing secondary growth along one of the {200} facets of parent orthorhombic CsPbBr3 cube nanocrystals and led to the unique star shaped nanocrystals which consumed smaller size cube nanocrystals and continued to grow further. The method is also extended to CsPbCl3 nanocrystals. Due to complex shapes, these are further explored as photocatalysts for CH4 and CO evolution under purging CO2 gas in ethyl acetate/water medium, and their catalytic activities are compared with cube nanocrystals.