On the electronic structures and conduction properties of quasi-one-dimensional copolymers (type-II staggered) of donor-acceptor polymers

摘要

Using an-initio band structure results of two novel donor-acceptor polymers PPDCH [A]_x and PPDCN [B]_x as the input, the electronic structures and conduction properties of their various periodic and aperiodic copolymers (A_mB_n)_x have been investigated using negative factor counting method based on Dean's negative eigen value theorem. These polymers consist of a bicyclopentadienylene unit bridged by an electron accepting group Y (where Y=>C=CH_2 in PPDCH and >C=C(CN)_2 in PPDCN) as the repeat unit. The copolymers, on the basis of the band alignments of the two constituent homopolymers, are found to belong to the class of type-II staggered superlattices. The trends in their electronic structures and conduction properties as a function of (i) composition (m), (ii) block sizes a and n and (iii) arrangement of the blocks (periodic or aperiodic) in the various copolymer chains are discussed. The trends are important guidelines for designing novel electrically conducting copolymers.