The Unusual Effect of Bandgap Lowering by C₆₀ on a Conjugated Polymer

Abstract

Polymers with lowered bandgaps (see Figure) are produced from monomers containing a bisfulleroid as an electron-acceptor and thiophene as an electron-donor, fused by a thieno[3,4-b]pyrazine bridge. The bandgaps could reach as low as 0.25 eV. Electron flow from the poly(thiophene) backbone to the fullerene through the covalently bound thieno[3,4-b]pyrazine unit in the ground state makes this polymer a good candidate for the fabrication of photovoltaics and photoconductors.