Synthesis of two D‐π‐A polymers π‐bridged by different blocks and investigation of their photovoltaic property

The synthesis, characterization, photophysical and photovoltaic properties of two 5,6‐bis(octyloxy)benzo[c][1,2,5]thiadiazole‐containing wide‐band‐gap donor and acceptor D‐π‐A alternating conjugated polymers (HSD‐a and HSD‐b) have been reported. These two polymers absorb in the range of 300–700 nm with a band gap of about 1.88 and 1.97 eV. The HOMO energy levels were −5.44 eV for HSD‐a and −5.63 eV for HSD‐b. Polymer solar cells with HSD‐b :PC 71 BM as the active layer demonstrated a power conversion efficiency (PCE) of 2.59% with a high V oc of 0.93 V, a J sc of 7.3 mA/cm 2 , and a comparable fill factor (FF) of 0.38 under simulated solar illumination of AM 1.5G (100 mW/cm 2 ) without annealing. In addition, HSD‐a :PC 71 BM blend‐based solar cells exhibit a PCE of 2.15% with a comparable V oc of 0.64 V, J sc of 8.75 mA/cm −2 , and FF of 0.40. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 41587.