Royal Society of Chemistry, Nanoscale, 5(3), p. 2280, 2011
DOI: 10.1039/c0nr01002b
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Exciton quenching dynamics has been systematically studied in pristine P3HT and nano phase separated P3HT/PCBM blend films under various excitation intensities by femtosecond fluorescence up-conversion technique. The behaviors of excitons in the films can be well described by a three-dimensional diffusion model. The small diffusion length and large charge transfer radius indicate that excitons reach the interface most likely by the delocalization of the excitons in P3HT fibrillar at a range of 4.8-9 nm so that the excitons can quickly delocalize in the P3HT domain to reach the interface (instead of by diffusion).