Regioregular Copolymers of 3-alkoxythiophene and their Photovoltaic Application

The innovation involves the synthesis and characterization of optical and electrochemical properties of a regioregular copolymer poly (3-octylthiophene-25-diyl-co-3-decyloxythiophene-25-diyl) (POT-co-DOT) and an alternating regioregular copolymer poly{(99-dioctylfluorene)-27-diyl-alt-[47-bis(3-decyloxythien-2-yl)-213-benzothiadiazole]-55-diyl} (PF-co-DTB). The incorporation of 3-alkoxythiophene units onto the conjugated backbones enhances the electron-donating property of the polymer and lowers its bandgap. The fabrication and performance of photovoltaic cells with bulk heterojunction architecture based on blends of these copolymers with PCBM are also described. State of Development: Performance of bulk hetero-junction solar cells fabricated using blends of these polymers with PCBM was measured under white light illumination (AM 1.5 G 100 mW/cm2) the obtained short circuit current density (Jsc) was 6.3 mA/cm2 open circuit voltage (Voc) was 0.76V fill factor (FF) was 50.5% and PCE was 2.4 %. Study to further improve the solar cell architecture and power conversion efficiency is underway.