Enhancing the Photocatalytic Performance of CsPbBr₃ Nanocrystals through Ferrocene-Assisted Exciton Dissociation and Halide Vacancies

Excited-state interactions at the interfaces of nanocrystals play a crucial role in determining photocatalytic efficiency. CsPbBr₃ nanocrystals (CPB NCs), celebrated for their exceptional photophysical properties, have been explored for organic photocatalysis. However, their intrinsic limitations, such as charge carrier recombination and stability issues, hinder their full potential. Strategies to enhance exciton dissociation, such as complexing CPB NCs with charge-shuttling molecules, have shown promise but remain underexplored for fully realizing their potential in improving the photocatalytic performance. We coupled ferrocene carboxylic acid (FcA) with CPB to extract the photogenerated holes, leveraging them to oxidize (1,2-dibromoethyl)benzene to phenacyl bromide. Optimization using pristine CPB NCs achieved a production rate of 5 μmol g_cat^-1 h^-1, which increased to 13.1 μmol g_cat^-1 h^-1 upon FcA incorporation, marking a 2.5-fold enhancement. Mechanistic investigations revealed the simultaneous involvement of electrons and holes, with oxygen acting as a reactant contributing to the oxygenated product. Halide vacancies were identified as critical adsorption sites for the substrate, with post-synthetic treatments enhancing these vacancies, resulting in over a 2-fold increase in the reaction rate. This work not only establishes an effective approach for phenacyl bromide synthesis but also highlights the potential of leveraging dissociated charge carriers to enhance photocatalysis using CPB NCs.