Low Band Gap Polymers Design Approach Based on a Mix of Aromatic and Quinoid Structures

This article establishes a link between the structural form of a polymer and its light absorption properties using density functional theory. According to a relationship established for 200 polymers from a wide range of different families, it is found that low band gap polymers can be designed with a mix of the quinoid and the aromatic structures. This characteristic can be obtained by synthesizing a copolymer containing quinoid monomers with aromatic ones. This promising approach of polymer design offers noticeably better predictions than the commonly used donor-acceptor approach and can be used as a fast method to obtain band gap properties of any copolymer using only information on homopolymers. Using this design approach, we present 31 new polymers with theoretical band gaps between 0.75 and 1.30 eV, 10 of which are under 1 eV.