We report the results of steady-state photoinduced absorption experiments on PDA-4BCMU grown on silica substrate. We observe three photoinduced absorption bands at 0.82, 0.95, and 1.39 eV whose relaxation dynamics are identical for the two low-energy peaks but different for the 1.39-eV band. On the basis of the spectra, the pump intensity, modulation frequency, and signal phase dependences we conclude that the 0.82 and 0.95-eV absorption features are due to charged states while the 1.39-eV peak is originated by triplet excitons. The photogeneration of both charged and neutral states in PDA-4BCMU as previously observed in polycarbazolyldiacetylenes indicates that this is a general feature of polydiacetylenes. The relative weight of one excited species over the other one is influenced by the molecular and supramolecular organization of the polymer.
LONG-LIVED PHOTOEXCITED STATES IN POLYDIACETYLENES: THE PHOTOINDUCED-ABSORPTION SPECTRA OF PDA-4BCMU
COMORETTO, DAVIDE;CUNIBERTI, CARLA EMILIA;MUSSO, GIANFRANCO;DELLEPIANE, GIOVANNA;
1998-01-01
Abstract
We report the results of steady-state photoinduced absorption experiments on PDA-4BCMU grown on silica substrate. We observe three photoinduced absorption bands at 0.82, 0.95, and 1.39 eV whose relaxation dynamics are identical for the two low-energy peaks but different for the 1.39-eV band. On the basis of the spectra, the pump intensity, modulation frequency, and signal phase dependences we conclude that the 0.82 and 0.95-eV absorption features are due to charged states while the 1.39-eV peak is originated by triplet excitons. The photogeneration of both charged and neutral states in PDA-4BCMU as previously observed in polycarbazolyldiacetylenes indicates that this is a general feature of polydiacetylenes. The relative weight of one excited species over the other one is influenced by the molecular and supramolecular organization of the polymer.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.