Forster resonance energy transfer in mixed-size CdTe quantum dots with optimized donor-acceptor concentration ratio

Abstract

The dynamics of Forster resonance energy transfer (FRET) in mixed-size water-soluble CdTe quantum dots (QDs) are studied by using photoluminescence (PL) and time-resolved PL spectroscopy. When donor concentration is increased, an enhancement of both the FRET and quantum efficiency in the mixed-size CdTe QDs films can be observed. Increasing donor concentration significantly quenches the emission intensity and lifetime in donor QDs and enhances that in acceptor QDs. However, as D/A ratios exceed 6, the emission intensity and the lifetime of acceptor QDs start to decline, reflecting a decreasing in both quantum and FRET efficiency due to a markedly declining availability of acceptor QDs.