Effect of additional donor group on the charge transfer/recombination dynamics of a photoactive organic dye: A quantum mechanical investigation

•Charge transfer/recombination dynamics of some organic dyes are studied theoretically.•The excited state properties of the dyes are characterized.•Rates of charge transfer/recombination are computed on the basis of Marcus theory.•Photovoltaic properties of D-A and D-A-D types of dyes are compared.

A quantum chemical analysis has been performed on the charge transfer/recombination dynamics of a photoactive organic dye having architecture donor-acceptor-donor (D-A-D). Density functional and time-dependent density functional theory calculations reveal that the chromophore shows an excellent charge separation upon excitonic dissociation. The excited state properties were determined by visualizing the charge density difference and transition densities. We evaluate inter electronic coupling matrix on the basis of Generalized Mulliken-Hush model for the dye as well as dye-TiO2 nanocluster and thus we predict the charge transfer and charge recombination rates. Overall, a comparative study between the D-A and D-A-D types of systems has been made to show the effect of one additional donor group on the charge transfer/recombination dynamics.

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