Conjugated Polymers with Broad Absorption: Synthesis and Application in Polymer Solar Cells

A series of main chain donor-acceptor low-bandgap conjugated polymers were designed, synthesized, and used for the fabrication of polymer solar cells. The absorption spectra of low-bandgap conjugated polymers were tuned by the ratio of three copolymerization monomers The polymers in films exhibited broad absorption ranging from 300 to 1000 nm with optical bandgaps of around 1 40 eV All of the polymers have been investigated as an electron donor in photovoltaic cells blending with PCBM ([6, 6]-phenyl C61-butyric acid methylester) as an electron acceptor and power conversion efficiencies (PCEs) of 1 32-1 8% have been obtained As for P1, PCE increases from 1 67 to 2 44% after adding 1,8-diiodooctance as an additive The higher PCEs are probably because of better phase separation of blend films. (C) 2010 Wiley Periodicals, Inc J Polym Sci Part A Polym Chem 48 2571-2578, 2010