Exciton Dynamics in Alternating Polyfluorene/Fullerene Blends
2008 (English)In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 350, no 1-3, 14-22 p.Article in journal (Refereed) Published
Exciton dynamics in alternating copolymer/fullerene solar cell blends have been investigated using femtosecond transient absorption spectroscopy. The acceptor concentrations have been varied over a wide range. Experimental data, kinetic modeling and simulations, all indicate that the efficiency of exciton conversion to charges is 100% even at acceptor concentrations as low as 20 wt%. The reported dependence of solar cell efficiency on fullerene concentration may thus arise from other factors. However, there exists an acceptor concentration threshold (5 wt%) below which a substantial fraction of the excitations remain unquenched. The results, we believe are very relevant to optimization of performance efficiency by clever manipulation of morphology. We have also observed exciton–exciton energy transfer in these blends at low acceptor concentrations.
Place, publisher, year, edition, pages
College Park, MD, United States: American Institute of Physics (AIP), 2008. Vol. 350, no 1-3, 14-22 p.
Exciton dynamics; Polyfluorene/fullerene blends
IdentifiersURN: urn:nbn:se:liu:diva-44513DOI: 10.1016/j.chemphys.2007.11.018ISI: 000257539500004Local ID: 76940OAI: oai:DiVA.org:liu-44513DiVA: diva2:265375