Highly efficient Fِrster resonance energy transfer between CdTe nanocrystals and Rhodamine B in mixed solid films

We report evidence for highly efficient Förster resonance energy transfer between CdTe nanocrystals (donors) and Rhodamine B (acceptors) in mixed solid films. Enhancement of the acceptor photoluminescence intensity and a decrease of the donor decay time are observed in the films containing nanocrystals mixed with Rhodamine B. For a wide range of films with a ratio between the amount of acceptors and the amount of donors of 0.2–5, an efficiency of energy transfer of more than 20% is estimated from time resolved measurements.