Discrimination between FRET and non-FRET quenching in a photochromic CdSe quantum dot/dithienylethene dye system.

A photochromic Förster resonance energy transfer (FRET) system was employed to disentangle the fluorescence quenching mechanisms in quantum dot/photochromic dye hybrids. In the off-state of the dye the main quenching mechanism is FRET whereas the moderate quenching in the on-state is due to non-FRET pathways opened up upon assembly.