Chirality Control of Electron Transfer in Quantum Dot Assemblies

Electron spin and molecular chirality are emerging as factors that can be used effectively to direct charge flow at the molecular scale. We report order of magnitude effects of molecular chirality on electron-transfer rates between quantum dots (QDs) in chiral QD assemblies. Indeed, both the circular polarization of the light that excites the electron donor and the imprinted chirality of the acceptor QDs affect the dot-to-dot electron-transfer kinetics. We define a polarization for the electron-transfer rate constant and show that it correlates with the strength of the acceptor QD circular dichroism (CD) spectrum. These findings imply that the CD strength of the QD exciton transition(s) may be used as a predictor for the spin-dependent electron transfer, indicating that chiral imprinting of the dots may lie at the origin of this phenomenon.