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Updated: Jul 4, 2025

Compact Quantum Dots for Single-molecule Imaging
Published on: October 9, 2012
Two-Dimensional Electronic Spectroscopy Reveals Dynamics within the Bright Fine Structure of CdSe Quantum Dots
Patrick Brosseau1, Dipti Jasrasaria2, Arnab Ghosh1
1Department of Chemistry, McGill University, Montreal H3A 0G4, Canada.
Abstract:
Semiconductor quantum dots are characterized by a discrete excitonic structure featuring coarse as well as fine structure. The lowest fine structure states have splittings into bright-dark states which are now well confirmed by single dot spectroscopy. In contrast, the splitting of the lowest coarse exciton into bright-bright fine structure states has not been observed nor the dynamics between these states. Here, we use the unique combination of time and energy resolution of two-dimensional electronic spectroscopy to directly observe the fine structure splittings into a bright-bright doublet. These splittings are strongly size dependent, with population relaxation on the <100 fs time scale.
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