Fluorinated copper phthalocyanine nanowires for enhancing interfacial electron transport in organic solar cells

Seok Min Yoon, Sylvia J. Lou, Stephen Loser, Jeremy Smith, Lin X. Chen, Antonio Facchetti, Tobin J Marks

Research output: Contribution to journalArticle

77 Citations (Scopus)

Abstract

Zinc oxide is a promising candidate as an interfacial layer (IFL) in inverted organic photovoltaic (OPV) cells due to the n-type semiconducting properties as well as chemical and environmental stability. Such ZnO layers collect electrons at the transparent electrode, typically indium tin oxide (ITO). However, the significant resistivity of ZnO IFLs and an energetic mismatch between the ZnO and the ITO layers hinder optimum charge collection. Here we report that inserting nanoscopic copper hexadecafluorophthalocyanine (F16CuPc) layers, as thin films or nanowires, between the ITO anode and the ZnO IFL increases OPV performance by enhancing interfacial electron transport. In inverted P3HT:PC61BM cells, insertion of F 16CuPc nanowires increases the short circuit current density (J sc) versus cells with only ZnO layers, yielding an enhanced power conversion efficiency (PCE) of ∼3.6% vs ∼3.0% for a control without the nanowire layer. Similar effects are observed for inverted PTB7:PC71BM cells where the PCE is increased from 8.1% to 8.6%. X-ray scattering, optical, and electrical measurements indicate that the performance enhancement is ascribable to both favorable alignment of the nanowire π-π stacking axes parallel to the photocurrent flow and to the increased interfacial layer-active layer contact area. These findings identify a promising strategy to enhance inverted OPV performance by inserting anisotropic nanostructures with π-π stacking aligned in the photocurrent flow direction.

Original languageEnglish
Pages (from-to)6315-6321
Number of pages7
JournalNano Letters
Volume12
Issue number12
DOIs
Publication statusPublished - Dec 12 2012

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Keywords

  • copper hexadecaphthalocyanine
  • interfacial layers
  • nanowire
  • Organic solar cell
  • zinc oxide

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanical Engineering

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