Enhanced photoredox activity of CsPbBr₃ nanocrystals by quantitative colloidal ligand exchange

Quantitative colloidal ligand exchange on lead-halide perovskite nanocrystals (NCs) has remained a challenge due to the dynamic passivation of amines and carboxylic acids and the instability of core lead-halide perovskite systems. Here, we present a facile colloidal ligand exchange process using cinnamate acid ligands to quantitatively displace native oleate ligands on CsPbBr₃ NCs. The short cinnamate ligands lead to a 23-fold enhancement of the electron-donating ability of the CsPbBr₃ NCs when benzoquinone is used as an electron acceptor. A significantly increased photoredox activity is also observed in a complete photocatalytic reaction: the α-alkylation of aldehydes. Our results provide a new strategy to tune the photoredox activity of halide perovskite NCs as well as the exploration of NC-ligand interactions.