Highly efficient FRET-based light-harvesting using nanocrystals

The use of nanocrystals in dye based applications has been increasing owing to the advantages of nanocrystals including small size, high efficiency, and tunable absorption and emission characteristics. Solubility and emission with high quantum yield in water is an issue for nanocrystals in biological applications. One of the best candidates is CdTe nanocrystals, which are highly efficient and soluble in water as synthesized. These make CdTe a highly preferable choice also for dye related biological applications. In this work, we employ CdTe nanocrystals as donors for nonradiative energy transfer to acceptor Rhodamine B dye molecules that are in their close proximity in solution. By varying the acceptor to donor concentration ratio (A/D) in solution, we show substantial modifications of the photoluminescence decay lifetimes of the donors from 25.3 ns to 7.2 ns as a result of efficient energy transfer and demonstrated enhanced emission of acceptor dyes. This leads to new possibilities for spectral multiplexing using dyes in conjunction with nanocrystals in biological applications.