Activated Singlet Exciton Fission in a Semiconducting Polymer Academic Article uri icon

abstract

  • Singlet exciton fission is a spin-allowed process to generate two triplet excitons from a single absorbed photon. This phenomenon offers great potential in organic photovoltaics, but the mechanism remains poorly understood. Most reports to date have addressed intermolecular fission within small-molecular crystals. However, through appropriate chemical design chromophores capable of intramolecular fission can also be produced. Here we directly observe sub-100 fs activated singlet fission in a semiconducting poly(thienylenevinylene). We demonstrate that fission proceeds directly from the initial 1Bu exciton, contrary to current models that involve the lower-lying 2Ag exciton. In solution, the generated triplet pairs rapidly recombine and decay through the 2Ag state. In films, exciton diffusion breaks this symmetry and we observe long-lived triplets which form charge-transfer states in photovoltaic blends.

author list (cited authors)

  • Musser, A. J., Al-Hashimi, M., Maiuri, M., Brida, D., Heeney, M., Cerullo, G., Friend, R. H., & Clark, J.

publication date

  • January 1, 2013 11:11 AM