Designing the surfaces of semiconductor quantum dots for colloidal photocatalysis

This Perspective reviews strategies for tuning the surface chemistry of colloidal semiconductor nanocrystals (quantum dots, QDs) to function as photoredox catalysts or sensitizers of redox catalysts for organic transformations. These strategies include (i) tuning surface charge density to encourage high-affinity interactions between the QD and substrate (or co-catalyst) in the absence of a covalent linkage, (ii) maximizing the QD's catalytic surface area through ligand exchange, (iii) using "hole shuttle" ligands to efficiently extract oxidative equivalents from the QD core, and (iv) controlling the concentration of protons on the QD surface to lower the kinetic barrier for proton-coupled electron-transfer reactions.