Optical spectroscopies of excited states in poly(para phenylene vinylene)

We have applied a multitude of continuous wave and pulsed optical spectroscopies to thin films of unsubstituted poly(para-phenylene vinylene) (PPV) with photoluminescence quantum efficiency ≥30%. Laser action in thin films, microdisks and microrings has been demonstrated. The threshold for lasing is comparable to other PPV derivatives. Electroabsorption unambiguously shows that the mAg state is located at 3.4 eV. At higher photon energies no large polarizability of excited states could be found. The photoinduced absorption spectrum which contains both polaron and triplet excitations is very weak, showing a relatively defect free polymer.