Effects of Solvent Mixtures on the Nanoscale Phase Separation in Polymer Solar Cells

Authors

  • Yan Yao,

    1. Department of Materials Science and Engineering and California Nanosystems Institute University of California Los Angeles Los Angeles, CA 90095 (USA)
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  • Jianhui Hou,

    1. Department of Materials Science and Engineering and California Nanosystems Institute University of California Los Angeles Los Angeles, CA 90095 (USA)
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  • Zheng Xu,

    1. Department of Materials Science and Engineering and California Nanosystems Institute University of California Los Angeles Los Angeles, CA 90095 (USA)
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  • Gang Li,

    1. Solarmer Energy Inc. El Monte, CA 91731 (USA)
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  • Yang Yang

    Corresponding author
    1. Department of Materials Science and Engineering and California Nanosystems Institute University of California Los Angeles Los Angeles, CA 90095 (USA)
    • Department of Materials Science and Engineering and California Nanosystems Institute University of California Los Angeles Los Angeles, CA 90095 (USA).
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  • This work was financially supported by Solarmer Energy Inc., UC Discovery Grant (Grant No. GCP05-10208), and Office of Navy Research (Grant No. N00014-01-1-0136, program manager Dr. Paul Armistead). We appreciate Mr. Hyun Cheol Lee for the help on TEM measurement and Dr. Yue Wu for helpful discussion.

Abstract

The mixed solvent approach has been demonstrated as a promising method to modify nanomorphology in polymer solar cells. This work aims to understand the unique role of the additive in the mixture solvent and how the optimized nanoscale phase separation develops laterally and vertically during the non-equilibrium spin-coating process. We found the donor/acceptor components in the active layer can phase separate into an optimum morphology with the additive. Supported by AFM, TEM and XPS results, we proposed a model and identified relevant parameters for the additive such as solubility and vapor pressures. Other additives are discovered to show the ability to improve polymer solar cell performance as well.

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