Fused structures in the polymer backbone to investigate the photovoltaic and electrochromic properties of donoracceptor-type conjugated polymers

In this study, two new benzotriazole (BTz) and dithienothiophene (DTT) containing conjugated polymers were synthesized. After successful characterizations of the monomers by proton-nuclear magnetic resonance (1H NMR) and carbon-NMR (13C NMR) techniques, poly(4-(dithieno[3, 2-b:2,3-d]thiophen-2-yl)-2-(2-octyldodecyl)-2H-benzo[d][1,2,3] triazole) P1 and poly(4-(5-(dithieno[3,2-b:2,3-d]thiophen-2-yl)thiophen-2-yl)-2-(2-octyldodecyl)-7-(thiophen-2-yl)-2H-benzo[d][1,2,3]triazole) P2 were synthesized via a typical Stille coupling. Electrochemical and spectroelectrochemical studies showed that both polymers can be multipurpose materials and used in electrochromic and photovoltaic applications. Reported study indicated that incorporation of DTT into the structure leads to fast switching times compared with BTz-based polymers and competent percentage transmittance in the near-infrared region. Multichromism is important in the context of low-cost flexible display device technology and both polymers are ambipolar and processable as well as multichromic. Throughout the preliminary photovoltaic studies, the best performances of photovoltaic devices were found as Voc = 0.49 V, Jsc = 0.83 mA/cm2, fill factor (FF) = 34.4%, and power conversion efficiency (PCE) = 0.14% for P1, and as Voc = 0.35 V, Jsc = 1.57 mA/cm2, FF = 38.2%, and PCE = 0.21% for P2. (c) 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013, 51, 1933-194