Formation of Well-Ordered Heterojunctions in Polymer:PCBM Photovoltaic Devices

Authors

  • Ximin He,

    1. The Nanoscience Centre, University of Cambridge, 11 J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
    2. Melville Laboratory, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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  • Feng Gao,

    1. Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
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  • Guoli Tu,

    1. Melville Laboratory, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
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  • David G. Hasko,

    1. Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
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  • Sven Hüttner,

    1. Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
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  • Neil C. Greenham,

    Corresponding author
    1. Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
    • Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom.
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  • Ullrich Steiner,

    Corresponding author
    1. Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
    • Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom.
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  • Richard H. Friend,

    Corresponding author
    1. Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
    • Cavendish Laboratory, Department of Physics, University of Cambridge, J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom.
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  • Wilhelm T. S. Huck

    Corresponding author
    1. The Nanoscience Centre, University of Cambridge, 11 J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
    2. Melville Laboratory, Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, United Kingdom
    3. Radboud University Nijmegen, Institute for Molecules and Materials, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
    • The Nanoscience Centre, University of Cambridge, 11 J. J. Thomson Avenue, Cambridge CB3 0FF, United Kingdom
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Abstract

The nanoscale morphology in polymer:PCBM based photovoltaic devices is a major contributor to overall device performance. The disordered nature of the phase-separated structure, in combination with the small length scales involved and the inherent difficulty of reproducing the exact morphologies when spin-coating and annealing thin blend films, have greatly hampered the development of a detailed understanding of how morphology impacts photo­voltaic device functioning. In this paper we demonstrate a double nano­imprinting process that allows the formation of nanostructured polymer:PCBM heterojunctions of composition and morphology that can be selected independently. We fabricated photovoltaic (PV) devices with extremely high densities (1014 mm−2) of interpenetrating nanoscale columnar features (as small as 25 nm; at or below the exciton diffusion length) in the active layer. By comparing device results of different feature sizes and two different polymer:PCBM combinations, we demonstrate how double imprinting can be a powerful tool to systematically study different parameters in polymer photovoltaic devices.

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