Low-Temperature, Solution-Processed Molybdenum Oxide Hole-Collection Layer for Organic Photovoltaics

Scott R. Hammond, Jens Meyer, N. Edwin Widjonarko, Paul F. Ndione, Ajaya K. Sigdel, Andrés Garcia, Alexander Miedaner, Matthew T. Lloyd, Antoine Kahn, David S. Ginley, Joseph J. Berry, Dana C. Olson

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153 Scopus Citations


We have utilized a commercially available metal-organic precursor to develop a new, low-temperature, solution-processed molybdenum oxide (MoO x) hole-collection layer (HCL) for organic photovoltaic (OPV) devices that is compatible with high-throughput roll-to-roll manufacturing. Thermogravimetric analysis indicates complete decomposition of the metal-organic precursor by 115 °C in air. Acetonitrile solutions spin-cast in a N 2 atmosphere and annealed in air yield continuous thin films of MoO x. Ultraviolet, inverse, and X-ray photoemission spectroscopies confirm the formation of MoO x and, along with Kelvin probe measurements, provide detailed information about the energetics of the MoO x thin films. Incorporation of these films into conventional architecture bulk heterojunction OPV devices with poly(3-hexylthiophene) and [6,6]-phenyl-C 61 butyric acid methyl ester afford comparable power conversion efficiencies to those obtained with the industry-standard material for hole injection and collection: poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS). The MoO x HCL devices exhibit slightly reduced open circuit voltages and short circuit current densities with respect to the PEDOT:PSS HCL devices, likely due in part to charge recombination at Mo 5+ gap states in the MoO x HCL, and demonstrate enhanced fill factors due to reduced series resistance in the MoO x HCL.

Original languageAmerican English
Pages (from-to)3249-3254
Number of pages6
JournalJournal of Materials Chemistry
Issue number7
StatePublished - 21 Feb 2012

NREL Publication Number

  • NREL/JA-2C00-54322


  • organic
  • photovoltaics
  • solar energy


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