Quantum dots (QDs) could harvest and converging sunlight more efficiently than bulk materials. Tuning of the QD’s surface via chemical functionalization provides additional channel for improving and manipulation of charge transfer – the key process in energy conversion. Here we use DFT and TDDFT simulations to study two types of QDs (Cd33Se33 and Zn33O33) with different metal-organic complexes adsorbed on the surface, as hole-extracting agent to suppress the internal recombination rates between photoexcited electrons and holes in QDs. Independent on its attachment and the QD type all complexes introduce additional states at the edge of the QD conduction band. These states are mainly localized on bipyridine ligands and govern the direction of electron transfer in these systems. Change in a transition metal of the complex insignificantly affects the alignment of the electronic levels of the dye versus the QD’s states. In contrast, a negative charge on the ligands coordinated with metal in the dye results in a shift of dye-associated orbitals towards the very edge of the QD valence band and provides the preferential conditions for the hole transfer from the QD to the dye. DFT-based nonadiabatic dynamics within Tully surface hopping technique is also carried out for these systems to obtain the rates of electron and hole transfer from the QD to the dye.

First principle study on optimizing conditions for charge transfer in quantum dots through dye functionalization

249th National Meeting (2015)

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