Limiting intersystem crossing in conjugated polymers by molecular design

A study of triplet dynamics in related polythiophene derivatives is reported in this communication. The authors found that replacing every third thienyl ring with a furanyl ring increases the triplet lifetime by half, whilst replacing thienyl rings with phenylene rings has an even more dramatic effect. It is also shown that steric effects associated with the position of side-chain substitution can significantly affect triplet lifetimes as well. Chemical design can thus be used to reduce intersystem crossing rates in conjugated polymers and leads to higher emission efficiencies.