Electronic structure and conduction properties of copolymers of silole based donor–acceptor polymers: effect of multi-neighbour interaction

Using the ab initio band structure results of two novel silole based donor–acceptor polymers PSICF (A)x and PSICN (B)x, the electronic structures and conduction properties of their various quasi-one-dimensional superlattices (copolymers) (AmBn)x, belonging to the class of type-II staggered superlattices, have been investigated using negative factor counting method taking into account multi-neighbour interaction. Both PSICF and PSICN consist of a bicyclopentadisilole unit bridged by an electron-accepting group Y (Y=CCF2 in PSICF and Y=CC(CN)2 in PSICN). The trends in the electronic structures and conduction properties of these copolymers (AmBn)x as a function of the (i) block sizes m and n; (ii) composition (m/n) and (iii) arrangement of blocks (periodic or aperiodic) in the copolymer chain are discussed. The results obtained are important guidelines for designing copolymers with tailor-made conduction properties.