Quantum dots acting as energy acceptors with organic dyes as donors in solution.

Quantum dots (QDs) usually act as energy donors in Förster resonant energy transfer (FRET) in various application fields. We report, for the first time, a FRET process from a conventional naphthalimide chromophore 1 to CdSe/ZnS core/shell QDs (acting as energy acceptors) in (1)-QDs hybrid system in solution. This FRET process is supported by various spectroscopies, such as steady-state and time-resolved photoluminescence (PL) as well as PL excitation spectra. The highest energy transfer efficiency is estimated to be about 0.37. Interestingly, the role of QDs in FRET can be specifically reversed (from energy acceptors to energy donors) with the use of QDs with larger band-gaps.