Synthesis and characterization of dialkoxynaphthalene-based new π-conjugated copolymer for photovoltaic solar cell

A π-conjugated dialkoxynaphthalene-based donor-acceptor copolymer was synthesized by a Suzuki coupling reaction, and its photophysical, thermal and electrochemical properties and photovoltaic characteristics were characterized. The copolymer showed good solubility and a weight average molecular weight of 11,500. The new copolymer was characterized by two absorption bands at 315 and 403 nm in the dilute solution, which were assigned to the π→π* transition and an intramolecular charge transfer band, respectively. The wide band gap of the donor-acceptor copolymer was explained by the 3-dimensional structure and tortional angle between the dialkoxynaphthalene and benzothiadiazole of the model compound. The PCE of the photovoltaic solar cell device fabricated using this copolymer reached 0.06% with a V _oc, J _sc, and FF of 0.59, 0.3, and 33%, respectively.