Controlling interfacial charge separation and recombination dynamics in QDs by wave function engineering

Abstract

In addition to the size dependent optical and electronic properties of semiconductor quantum dots (QDs), quantum confinement also affects the charge separation and recombination dynamics in QD - charge acceptor complexes. It leads to enhanced amplitudes of electron and hole wave functions at the surface, enabling ultrafast interfacial charge transfer, an important property for the application of QDs in photovoltaic and photocatalytic devices. In this proceeding, we show that both charge separation and recombination are ultrafast in strongly quantum confined PbS QDs adsorbed with electron acceptors. Using CdSe/ZnS type I and CdTe/CdSe type II core/shell QDs as model systems, we show that the spatial distributions of electron and wave functions can be optimized to simultaneously achieve ultrafast charge separation and retard charge recombination.