Electronic structures of donor-acceptor polymers based on polythiophene, polyfuran and polypyrrole

Abstract

Theor. results on the geometric and electronic structures of some donor-acceptor polymers based on polythiophene (X = S), polyfuran (X = O) and polypyrrole (X = NH) were obtained, using a one-dimensional tight-binding SCF crystal-orbital (SCF-CO) method at the MNDO-AM1 level of approxn. The repeat unit of these polymers consists of a bithiophene, furan or bipyrrole unit bridged by an electron-accepting group Y (Y = >C=CH2, >C=O >C=CF2 or, >C=C(CN)2). The optimized geometries of the polymers show a strong dependence on the nature of the electron donating group X. All the polymers studied are predicted to have band gap values ranging between 1 eV and 2 eV. An anal. of their π-bond order data and of the patterns of their frontier orbitals shows they have benzenoid-like electronic structures. [on SciFinder(R)]