Photophysics of a poly(phenylenevinylene) with alternating meta-phenylene and para-phenylene rings

Abstract

We have investigated the photophysics of the luminescent polymer poly ~ 1,3-phenylenevinylene- alt -2,5- dioctyloxy-1,4-phenylenevinylene ! by a variety of optical spectroscopies. The incorporation of alternating meta -phenylene and para -phenylene rings restricts conjugation with respect to poly ~ para -phenylenevinylene ! derivatives. As a consequence, excited states are blueshifted and the nonlinear susceptibility is reduced. Ab- sorption by aggregates, which can be obscured by scattering and interference, is clearly revealed by electro- absorption spectroscopy. The reduced symmetry of 1,3-PPV modifies optical selection rules, resulting in strong overlap of the fluorescence spectrum with excited state absorption by charged polarons.