We report time-resolved measurements of photoluminescence in poly(p-phenylenevinylene) (PPV) and related polymers, using the technique of time-correlated single photon counting. We find the photoluminescence is longer lived in less-conjugated samples, and that this accounts for the higher efficiency of light-emitting devices made from less-conjugated materials. At low temperatures, the luminescence is longer lived, and at 77 K there is an interesting red shift of the emission during the first nanoseconds after photoexcitation. We consider that this arises from migration of excitons to more-conjugated (and therefore lower energy) regions of the sample.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Materials Chemistry
- Polymers and Plastics