• Medientyp: E-Artikel
  • Titel: Molecular weight dependent vertical composition profiles of PCDTBT:PC71BM blends for organic photovoltaics
  • Beteiligte: Kingsley, James W.; Marchisio, Pier Paolo; Yi, Hunan; Iraqi, Ahmed; Kinane, Christy J.; Langridge, Sean; Thompson, Richard L.; Cadby, Ashley J.; Pearson, Andrew J.; Lidzey, David G.; Jones, Richard A. L.; Parnell, Andrew J.
  • Erschienen: Springer Science and Business Media LLC, 2014
  • Erschienen in: Scientific Reports
  • Sprache: Englisch
  • DOI: 10.1038/srep05286
  • ISSN: 2045-2322
  • Schlagwörter: Multidisciplinary
  • Entstehung:
  • Anmerkungen:
  • Beschreibung: <jats:title>Abstract</jats:title><jats:p>We have used Soxhlet solvent purification to fractionate a broad molecular weight distribution of the polycarbazole polymer PCDTBT into three lower polydispersity molecular weight fractions. Organic photovoltaic devices were made using a blend of the fullerene acceptor PC<jats:sub>71</jats:sub>BM with the molecular weight fractions. An average power conversion efficiency of 5.89% (peak efficiency of 6.15%) was measured for PCDTBT blend devices with a number average molecular weight of M<jats:sub>n</jats:sub> = 25.5 kDa. There was significant variation between the molecular weight fractions with low (M<jats:sub>n</jats:sub> = 15.0 kDa) and high (M<jats:sub>n</jats:sub> = 34.9 kDa) fractions producing devices with average efficiencies of 5.02% and 3.70% respectively. Neutron reflectivity measurements on these polymer:PC<jats:sub>71</jats:sub>BM blend layers showed that larger molecular weights leads to an increase in the polymer enrichment layer thickness at the anode interface, this improves efficiency up to a limiting point where the polymer solubility causes a reduction of the PCDTBT concentration in the active layer.</jats:p>
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