Search

A limitation of the implementation of cadmium chalcogenide quantum dots (QDs) in charge transfer systems is the efficient removal of photogenerated holes. Rapid hole transfer has typically required the ex situfunctionalization of hole acceptors with groups that can coordinate to the surface of the QD. In addition to being synthetically limiting, this strategy also necessitates a competitive binding equilibrium between the hole acceptor and native, solubilizing ligands on the nanocrystal. Here we show that the incorporation of oxygen vacancies into polyoxovanadate-alkoxide clusters improves hole transfer kinetics by promoting surface interactions between the metal oxide assembly and the QD. Investigating the reactivity of oxygen-deficient clusters with phosphonate-capped QDs reveals reversible complexation of the POV-alkoxide with a phosphonate ligand at the nanocrystal surface. These findings reveal a new method of facilitating QD–hole acceptor association that bypasses the restrictions of exchange interactions.

Colloidal semiconductor nanocrystals, or “quantum dots” (QDs), have several optical and chemical properties that give them the potential to enable nonincremental increases in the efficiencies of many types of photocatalytic reactions relevant for energy conversion and organic synthesis. Colloidal photocatalysts have many desirable characteristics of both heterogeneous and homogeneous catalysts but come with their own particular set of challenges. This viewpoint outlines some of the obstacles one first encounters when driving reactions with these colloids and offers some strategies for overcoming these obstacles, including ways to extend their excited state lifetimes, prevent corrosion by photogenerated holes, and choose a surface chemistry and buffering system for maximum colloidal stability over a range of environmental conditions.

The article reports on the presence of Illinois District Barbershoppers, a group of singers, at the 64th Annual Sterling-Rock Falls show on April 25, 2015.