New Donor-Acceptor Random Terpolymers with Wide Absorption Spectra of 300-1000 nm for Photovoltaic Applications

The development of conjugated polymers with wide absorption spectra is imperative to achieve high efficiency in polymer solar cells (PSCs), since most of these polymers usually absorb only a limited range of the solar spectrum. Random terpolymers consisting of three blocks (one electron-donor and two electron-acceptor blocks) are promising p-type polymers for PSCs, because the inclusion of a third block in the polymer macromolecules provides a synergistic effect of physical properties, such as absorption capacity, charge transfer, HOMO/LUMO energy levels, and photovoltaic characteristics. In this regard, we have developed and synthesized random terpolymers consisting of two different chromophores (DPP and BFCTP) with complementary absorption spectra as co-acceptor blocks in conjugated donor-acceptor (D-A) copolymers. Random copolymers exhibit both broad absorption and low HOMO levels favoring short-circuit current and idle voltage in PSCs. It is expected that new terpolymers consisting of one electron-donor unit and two electron-acceptor moieties will make a significant contribution to the development of highly efficient PSCs. It is expected that new ternary copolymers consisting of one electron-donor unit and two electron-acceptor fragments will make a significant contribution to the development of high-performance PSCs.