Point of Anchor: Impacts on Interfacial Charge Transfer of Metal Oxide Nanoparticles

Photoinduced charge transfer across the metal oxide–organic ligand interface plays a key role in the diverse applications of metal oxide nanomaterials/nanostructures, such as photovoltaics, photocatalysis, and optoelectronics. Thus far, most studies are focused on molecular engineering of the organic chromophores, where the charge-transfer properties have been found to dictate the photo absorption efficiency and eventual device performance. Yet, as the chromophores are mostly bound onto the metal oxide surfaces by hydroxyl or carboxyl anchors, the impacts of the bonding interactions at the metal oxide–ligand interface on interfacial charge transfer have remained largely unexplored. Herein, acetylene derivatives are demonstrated as effective surface capping ligands for metal oxide nanoparticles, as exemplified with TiO2, RuO2, and ZnO. Experimental studies and first-principles calculations suggest the formation of M–O–C≡C– core–ligand linkages that lead to effective interfacial charge delocalization, in co...