Control of Photoinduced Charge Transfer in Semiconducting Quantum Dot-Based Hybrids

Abstract

Self-assembly of water-soluble colloidal core/shell CdSe/ZnS quantum dots with varying ZnS shell thickness with a conjugated polyelectrolyte results in a series of inorganic/organic hybrids with tunable charge transfer properties and with the shell acting as a tunneling barrier towards photoinduced hole transfer from quantum dot to polymer. The rate for hole transfer decreases exponentially with the increase of quantum dot shell thickness and the hole transfer process is assessed to be a dynamic quenching process. An increase in hole transfer rate is observed from solution to thin-film phase and is related to an improved interfacial morphology in quantum dot/polymer affecting the hole transfer rate, namely the donor-acceptor distance. Single particle spectroscopy experiments reveal fluctuating dynamics of hole transfer at the conjugated polymer/quantum dot interface, increased heterogeneity in the hole transfer rate with the increase of quantum dot's shell thickness.