Excitation energy transfer in guest host systems studied by magnetic resonance techniques

Blending the conjugated ladder-type poly(paraphenylene) (LPPP) with small amounts of the red emitting poly(perylene-codiethynylbenzene) (PPDB), shifts the photoluminescence emission of the blends from blue to red due to an efficient excitation energy transfer (EET) of singlet excitons. We used the spin sensitive technique of photoluminescence detected magnetic resonance to monitor interchain polaron pairs and triplet excitons involved in the EET in differently concentrated m-LPPP/PPDB blends and in the pristine polymers. Polaron pairs and triplet excitons in PPDB and LPPP are distinct in their magnetic resonance signatures while the singlet excitons are distinct in their spectral emission position.