Intermolecular sequential energy transfer in thin films of a white emitting copolymer

摘要

The authors investigated the energy transfer between the chromophors of a white emitting polyspirobifluorene copolymer containing a blue emitting backbone, a green, and a red emitting dye. They demonstrate that the green dye is mainly excited by blue → green Foerster resonant energy transfer (FRET), with a Foerster radius R_(0bg) = 35 A. The red dye is instead excited by direct blue → red FRET (R_(0br) = 21 A) and by sequential blue → green → red FRET (R_(0gr) = 31 A). Finally, the authors show that the FRET processes, fundamental to have white emission, are of intermolecular nature, while intramolecular energy migration and transfer are negligible.