Ultrafast energy-transfer dynamics in a blend of electroluminescent conjugated polymers

Femtosecond pump–probe spectroscopy was applied to a guest–host system of conjugated polymers, the blue-emitting poly(para-phenylene) (m-LPPP) and the red-emitting poly(perylene-co-diethynylbenzene) (PPDB). Excitation energy transfer between m-LPPP and PPDB, monitored by the formation of the PPDB photobleaching band at 2.15 eV, takes place on a picosecond timescale. The non-exponential kinetics of the excitation energy transfer and its dependence on the acceptor (PPDB) concentration provide clear evidence for a Förster-type energy transfer.