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Title: Effect of molecular electrical doping on polyfuran based photovoltaic cells

Journal Article · · Applied Physics Letters
DOI:https://doi.org/10.1063/1.4921484· OSTI ID:22402474
; ;  [1];  [2]; ;  [3];  [1]
  1. Humboldt-Universität zu Berlin, Institut für Physik and IRIS Adlershof, Brook-Taylor Straße 6, 12489 Berlin (Germany)
  2. Helmholtz-Zentrum für Materialien und Energie GmbH, Bereich Solarenergieforschung, Albert-Einstein-Straße 15, 12489 Berlin (Germany)
  3. Department of Organic Chemistry, Weizmann Institute of Science, 76100 Rehovot (Israel)

The electronic, optical, and morphological properties of molecularly p-doped polyfuran (PF) films were investigated over a wide range of doping ratio in order to explore the impact of doping in photovoltaic applications. We find evidence for integer-charge transfer between PF and the prototypical molecular p-dopant tetrafluoro-tetracyanoquinodimethane (F4TCNQ) and employed the doped polymer in bilayer organic solar cells using fullerene as acceptor. The conductivity increase in the PF films at dopant loadings ≤2% significantly enhances the short-circuit current of photovoltaic devices. For higher doping ratios, however, F4TCNQ is found to precipitate at the heterojunction between the doped donor polymer and the fullerene acceptor. Ultraviolet photoelectron spectroscopy reveals that its presence acts beneficial to the energy-level alignment by doubling the open-circuit voltage of solar cells from 0.2 V to ca. 0.4 V, as compared to pristine PF.

OSTI ID:
22402474
Journal Information:
Applied Physics Letters, Vol. 106, Issue 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
Country of Publication:
United States
Language:
English