FRET in self-assembled CdTe quantum dot nanoclusters

Colloidal CdTe quantum dots (QDs) with oppositely charged ligand shells were used to form quantum dot nanoclusters in solution. The signatures of Forster non-radiative energy transfer in the photoluminescence and time-resolved photoluminescence data indicates that the electrostatic attraction draws the QDs into close proximity forming nanoclusters. The smaller QDs act as donors and the larger QDs act as acceptors within the cluster and a FRET efficiency of 45% has been recorded. Both the time-resolved and spectral PL data show a strong donor concentration dependence. The acceptor photoluminescence enhancement and FRET efficiency can be tuned by adjusting the donor acceptor ratio.