Because quantum dots (QDs) offer desirable photophysical properties including high quantum yields, photostability, and tunable emission wavelengths, QDs are used in imaging, photodetectors, photovoltaics, and other applications. Our group has a particular interest in characterizing the electronic interactions among closely-spaced QDs using both wide-field and confocal optical microscopy techniques. We monitor photoluminescent properties such as emission intensity, polarization, color, lifetime, and other photon arrival statistics that paint a picture of the underlying dynamics. Most recently, we have probed energy transfer pathways within CdSe/CdS core/shell QD assemblies using time-resolved super resolution imaging and found evidence of energy donors and acceptors suggestive of a Förster resonance energy transfer mechanism.
Pathways of photon emission (indicated by blue arrows) and energy transfer (indicated by red arrows) in a two-QD cluster in which green QDs have an exciton and orange QDs do not. Curved red arrows denote the direction of exciton transfer.