Controlling Rigidity and Planarity in Conjugated Polymers: Poly(3,4‐ethylenedithioselenophene)

Staying on a plane: Even small substituents on the backbone of conjugated polymers can cause them to twist significantly, lowering conjugation and leading to wider band gaps. Oligo- and polyselenophenes are more rigid than their thiophene analogues, and can maintain their planarity and low band gap with substituents that otherwise cause considerable twisting. The picture shows two selenophene dimers; Se magenta, S yellow.