Combination of donor characters in donor-acceptor-donor type polymers containing benzothiadiazole and quinoxaline as the acceptor units

Şendur, Merve
Donor-acceptor-donor approach is one of the effective ways to synthesize low band gap polymers. The monomers that will be designed with respect to donor-acceptor-donor approach have low band gap achieved by the coupling of a strong donor with high HOMO level to a strong acceptor with low LUMO level. Thus, the new donor-acceptor material will have a reduced bandgap (Eg) relative to either of its parent components. Due to this point of view, in this study, new electroactive benzothiadiazole and 2,3-bis(4-(tert-butyl)phenyl)quinoxaline monomers substituted with different donor groups (3,4-ethylenedioxythiophene and thiophene) were synthesized to explain the effect of different donor groups on the electronic and optical properties of DAD type polymers. The characterizations of the monomers were performed by 1H and 13C NMR techniques. Electrochemical behavior of both monomers and polymers were studied by cyclic voltammetry. The electrochromic properties of the synthesized conducting polymers were investigated by several methods like spectroelectrochemistry, kinetic and colorimetry studies. The polymers have two different donor units may behave as a copolymer of the symmetric monomer having the same donor groups. Hence, the properties of copolymers were investigated with the co-monomers having either thiophene or 3,4-ethylenedioxythiophene as the donor group.