Poly(2,5-dihexyloxyphenylene vinylene-alt-2,2-dibutylpropylenedioxythiophene): Synthesis and characterization for photovoltaic applications

A thiophene/phenylene vinylene-based polymer (P1) was synthesized and its properties compared with those of a previously described analogous polymer (P2-CN) which contains CN substituents in the vinyl moieties. In solution, the P1 polymer absorbed in a range from UV to near 600 nm and, compared to P2-CN, exhibited a band gap energy that was larger, from 1.7 to 2.0 eV, and the energy levels of LUMO and HOMO lower, by 0.2 and 0.5 V, respectively. However, the power conversion efficiencies (PCE, 0.30%) of photovoltaic devices fabricated using a blend of P1 and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) appeared to be slightly higher than the reported PCE (0.15%) for P2-CN devices fabricated in the same configuration.