Polarized optical and photoluminescence properties of highly oriented poly(p-phenylene-vinylene)

We report on the anisotropic reflectance (R), transmittance (T) and photoluminescence (PL) properties of stretch-oriented free standing films of poly(p-phenylene-vinylene) (PPV) at different temperatures. The PL quantum efficiency is strongly dependent on the pump polarization, being higher when the pump is polarized perpendicular to the polymer chain orientation. Independently of the pump polarization, we find that the PL emission spectra are mainly polarized along the polymer chain direction. The PL spectra have been corrected both for the number of absorbed photons and for self-absorption of the emitted light. Frank-Condon analysis of the oscillator strength for absorption and corrected emission spectra suggest that two different “chromophores” contribute to the optical properties.