A new highly stable polymer for solar cells and near-infrared applications

POLY 144

Ayça Erden, aycaerden@su.sabanciuniv.edu, Canan Baristiran, Osman El-Atwani, and Gürsel Sönmez. Faculty of Engineering and Natural Sciences, Sabanci University, Orhanli, Tuzla, Istanbul, 34956, Turkey
A new highly stable low band gap polymer, poly-4,7-dithien-2-yl-2,1,3-benzothiadiazole, was electrochemically synthesized, and its electrochemical, electrochromic, morphological properties are reported. The oxidation potential of the monomer was relatively low: 0.9 V vs. Ag/Ag+, and the E1/2 of the polymer was 0.65 V vs. Ag/Ag+. Electrochemically prepared polymer films were very stable upon reusage and against long-term switching up to 1000 cycles, moreover open circuit experiments showed that the material has a good memory effect. The low band gap of the polymer films, 1.10 eV, was determined from electrochemistry. Thin polymer films on ITO-coated glass slides showed exceptional optical properties upon both p- and n-doping, these were small changes in the transparency and color of the polymer in the visible region but more dramatic changes in the near-infrared region, making this polymer a good candidate for solar cells and near-infrared applications.