Phenylenevinylene copolymers of dihexylthienylbenzothiadiazole and triphenylamine or tetraphenylbenzidine: synthesis, characterization and photovoltaic properties

Three novel low-band gap phenylenevinylene copolymers (, , and ), containing dihexylthienylbenzothiadiazole (DTBT) and triphenylamine (TPA) or tetraphenylbenzidine (TPD) were synthesized via the Wittig-Horner reaction. The effects of TPA and TPD on the thermal, optical, electrochemical and photovoltaic properties were investigated. The UV-Vis spectrum of , which contains TPD in the polymer backbone, exhibits a broader and stronger absorption in the film than those of and . The bulk heterojunction solar cells were fabricated with the as-synthesized polymers as the donors and [6,6]-phenyl-C-61-butyric acid methyl ester as the acceptor in a 1:4 weight ratio. The device based on exhibits the maximum power conversion efficiency of 1.11 % under simulated AM 1.5 G solar irradiation (100 mW/cm(2)).