Phenylene-ethynylene/phenylene-vinylene hybrid polymers: optical and electrochemical characterization, comparison with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] and application in flexible polymer solar cells

Defect-free phenylene-ethynylene/phenylene-vinylene hybrid polymers (PPE-PPV) have been characterized optically and electrochemically. The presence of -C≡C- within the polymers backbone leads to higher oxidation potentials and higher optical band gaps compared with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylene vinylene] (MDMO-PPV). The new polymers were used as electron donor in polymer solar cells (PSCs). An effective charge transfer from polymer to [6,6]-phenyl C61-butyric acid methyl ester (PCBM) was found via the photoluminescence technique and light-induced electron spin resonance techniques. Photovoltaic devices were prepared on ambient conditions on flexible polyester foils coated with indium tin oxide (ITO) and showed power conversion efficiency (ηAM1.5) of 3% (MDMO-PPV:PCBM) and 1.75% as well as 0.5% (PPE-PPV:PCBM)