Doped Semiconductor Nanocrystals and Organic Dyes: An Efficient and Greener FRET System

We report here the Forster resonance energy transfer (FRET), from transition metal ion (Mn and Cu)-doped semiconductor nanocrystal (d-dots) donors to different organic dyes acceptors. Longer excited-state lifetime, high quantum yield in water, smaller size, and higher spectral overlap integral with acceptors make these doped nanocrystals efficient FRET donors with efficiency (E) up to 90%. Moreover, these doped nanocrystals whose emission covers almost the entire region of the visible window with variable excitations can couple with a large variety of organic dyes for energy transfer. Additionally, these are free from toxic cadmium element, which allows the exploration of their applications as greener and safer donors for FRET in different biological events.