Exciton dissociation by a static electric field followed by nanoscale charge transport in PPV polymer films

Abstract

The simultaneous study of the electric-field dependence of the photoluminescence and the photoinduced charge transport in the phenyl-substituted Super Yellow PPV derivative shows that charge carriers are created indirectly through field-induced ionization of excitons, and allows the identification of a free-carrier mobility larger than $\ensuremath{\sim}3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{0.2em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.2em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ that is valid for transport over a few nm during an apparent free-carrier lifetime of $\ensuremath{\sim}50\phantom{\rule{0.3em}{0ex}}\mathrm{ns}$. The time dynamics of the photoluminescence and its temperature-quenching behavior indicate the presence of two species of excitons, which can be interpreted as intrachain and interchain excitons.