Counter ion effects on the energy transfer processes in PPV

We report an enhanced luminescence of cast films of poly(p-phenylenevinylene) (PPV), where the energy transfer among adjacent polymer chains was controlled by varying the concentration of counterions in the synthesis. Using as precursor poly(xylylidenetetrahydrothiophenium) with dodecylbenzenesulfonate as counter ions (PTHT-DBS) in 1:3 M basis led not only to the strongest but also the most polarized emission. Both the intensity and degree of polarization could be controlled, provided that the conversion temperature was considerably lower than the Tg of PPV. These results may be exploited in optimizing organic electronic devices, for which annealing is needed.