Time-domain ab initio modeling of excitation dynamics in quantum dots

Abstract

The review discusses the results of ab initio time-dependent density functional theory and non-adiabatic molecular dynamics simulations of photoinduced dynamics of charges, excitons, plasmons, and phonons in semiconductor and metallic quantum dots (QDs). The simulations create an explicit time-domain representation of the excited-state processes, including elastic and inelastic electron–phonon scattering, multiple exciton generation, fission, and recombination. These nonequilibrium phenomena control the optical and electronic properties of QDs. Our approach can account for QD size and shape, as well as chemical details of QD structure, such as dopants, defects, core/shell regions, surface ligands, and unsaturated bonds. Each of these variations significantly alters the properties of photoexcited QDs. The insights reported in this review provide a comprehensive understanding of the excited-state dynamics in QDs and suggest new ways of controlling the photo-induced processes. The design principles that follow, guide development of photovoltaic cells, electronic and spintronic devices, biological labels, and other systems rooted in the unique physical and chemical properties of nanoscale materials.