Single-Molecule Measurements Spatially Probe States Involved in Electron Transfer from CdSe/CdS Core/Shell Nanorods

Semiconductor nanorods with charge-accepting molecules adsorbed on their surfaces serve as model systems for solar energy conversion. An electron photoexcited from the valence band of nanorod to a high-energy state in conduction will relax and transfer molecule, producing long-lived charge-separated that facilitates charge extraction thereby enables photochemical reactions. Characterizing dynamics charge-separation process electronic states involved is essential microscopic understanding photocatalysis involving these materials, but this information obscured ensemble measurements due random placement surfaces. Here, we show individual CdSe/CdS core/shell functionalized by single methyl viologen provide about distribution electron-transfer rates confined molecules. By comparing transfer-rate predictions tight-binding model, find most likely involves hot electrons an excited conduction-band state, rather than have fully thermalized edge. The ability extract semiconductor nanocrystals may help enable energy-efficient photocatalysis, single-particle charge-transfer method widely applicable tool probe spatial nanocrystals.