Exciton dissociation within quantum dot-organic complexes: Mechanisms, use as a probe of interfacial structure, and applications

This article reviews the structural and electronic features of colloidal quantum dot (QD)-organic complexes that influence the rate of photoinduced charge separation (PCS) across the interface between the inorganic core of the QD and its organic surface ligands. While Marcus theory can be used to describe the rate of PCS in QD-organic complexes, uncertainties in the exact atomic configuration of the inorganic-organic interface and heterogeneities in this interfacial structure within an ensemble of QDs complicate the determination of the most fundamental Marcus parameters - electronic coupling, reorganization energy, and driving force. This article discusses strategies for accounting for uncertainties and heterogeneities when using Marcus theory to interpret rates of PCS in QD-organic complexes and highlights how measurement of PCS rates can provide information about the interfacial structure of the QD surface. Recent progress in the application of mechanistic knowledge of PCS to harvest multiple charge carriers from QDs containing multiple excitons and extend the lifetime of the charge-separated state is also discussed.