Real-Time TDDFT Studies of Exciton Decay and Transfer in Silver Nanowire Arrays

Abstract

Understanding dynamical characteristics of excited electronic states is crucial for rational design of functional nanomaterials. Using real-time time-dependent density functional theory, we present a fully quantum mechanical study on the transfer and decay of an exciton in an archetypal metal nanostructure. We introduce several approaches to analyze the dipole moment’s time evolution to resolve exciton transfer rates and the pure dephasing times. These approaches are applied to studies of exciton diffusion length in a silver nanowire array. Calculated rates of polarization-induced transfer exhibit neither Forster’s “sixth-power” dependence on donor–acceptor distance nor the perfect exponential separation dependence that typifies the Dexter transfer mechanism, suggesting that the nonperturbative, ab initio quantum dynamics captures intricacies of exciton transfer between quantized nanosystems that are beyond the reach of the canonical models of electronic energy transfer.