Synthesis and optoelectronic property manipulation of conjugated polymer photovoltaic materials based on benzo[d]-dithieno[3,2-b;2′,3′-f]azepine

Abstract To develop new conjugated polymers (CPs) based on heteroepines, a soluble azepine moiety of benzo [ d ]-dithieno [3,2-b; 2′,3′- f ]azepine was copolymerized with different building blocks to obtain a series of CPs. A broad absorption range of 300–850 nm and the desired optical bandgaps (1.54–2.42 eV) are easily accessible by varying different copolymerization units. The HOMO levels of polymers are observed as an almost identical value of −5.21 eV and the LUMO levels range from −2.82 to −3.52 eV. Polymer solar cells (PSCs) with these polymers as donor materials were fabricated to explore application potentials in organic photovoltaics. Preliminary study exhibits the best power conversion efficiency of 1.28% for PSCs based on these polymers with a relatively high V oc of 0.84 V. Although photovoltaic performance of these new polymers is not as high as our expected, the first daring attempt provides some good references to expand application fields of azepine-based polymers.