Synthesis, characterization, and photophysical properties of novel poly(p-phenylene vinylene) derivatives with conjugated thiophene as side chains

Two novel poly(p-phenylene vinylene) (PPV) derivatives with conjugated thiophene side chains, P1 and P2, were synthesized by Wittig-Horner reaction. The resulting polymers were characterized by ¹H-NMR, FTIR, GPC, DSC, TGA, UV-Vis absorption spectroscopy and cyclic voltammetry (CV). The polymers exhibited good thermal stability and film-forming ability. The absorption spectra of P1 and P2 showed broader absorption band from 300 to 580 nm compared with poly[(p-phenylene vinylene)-alt-(2-methoxy-5-octyloxy-p-phenylene vinylene)] (P3) without conjugated thiophene side chains. Cyclic voltammograms displayed that the bandgap was reduced effectively by attaching conjugated thiophene side chains. This kind of polymer appears to be interesting candidates for solar-cell applications.