Energy transport along conjugated polymer chains with extended radiative lifetimes: a theoretical study.

The ability to improve exciton diffusion lengths is a key issue in optimizing many opto-electronic devices based on conjugated polymers. On the basis of quantum-chemical calculations, we investigate a strategy consisting of extending the radiative lifetime of energy carriers through incorporation along the polymer backbone of repeating units with forbidden optical transition. The results obtained for poly(p-phenylenebutadiyne), PPE, and poly(p-triphenylenebutadiyne), PTPE, show that the larger number of hops performed by the electronic excitations during their lifetime in PTPE is compensated by the smaller hopping length (associated with the reduced conjugation length), so that similar on-chain diffusion lengths are predicted in both polymers.