Ultrafast hole relaxation dynamics in quantum dots revealed by two-dimensional electronic spectroscopy

Abstract Elucidating the population dynamics of correlated electron-hole pairs (bound excitons) in semiconducting quantum dots (QDs) is key for developing our fundamental understanding nanoscale photophysics as well optimal design devices, such lasers. For decades, it was assumed that holes did not contribute to band edge bleach signals QDs. Here, we employ two-dimensional electronic spectroscopy monitor electron and hole both CdSe CdSe/CdS/ZnS QDs probe dynamics. Based on a combination time frequency resolution, observe previously unresolved bleaching signal timescales faster than 30 fs due cooling. Atomistic semiempirical pseudopotential calculations are used rationalize order magnitude difference observed This picture advances QD excitonics past prevailing continuum effective mass theories generally describe structure