Oxide Sandwiched Metal Thin-Film Electrodes for Long-Term Stable Organic Solar Cells

Authors

  • Sylvio Schubert,

    Corresponding author
    1. Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany
    • Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany.
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  • Martin Hermenau,

    1. Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany
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  • Jan Meiss,

    1. Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany
    Current affiliation:
    1. Reiner Lemoine Institut gGmbh, Ostendstraße 25, 12459 Berlin, Germany
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  • Lars Müller-Meskamp,

    Corresponding author
    1. Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany
    • Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany.
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  • Karl Leo

    1. Institut für Angewandte Photophysik, Technische Universität Dresden, George-Bähr Straße 1, 01062 Dresden, Germany
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Abstract

Oxide/silver/oxide multilayers as semitransparent top electrode for small molecule organic solar cells (OSCs) are presented. It is shown that two oxide layers sandwiching a central metal layer greatly improve the stability and lifetime of the organic solar cell. Thermally evaporated MoO3, WO3, or V2O5 layers are employed as an interlayer for subsequent silver deposition and significantly change the morphology of the ultrathin silver layer, improving charge extraction and electrodes series resistance. The transmittance of the electrode is increased by introducing oxide or oxide and organic multilayers as capping layer, which leads to higher photocurrent generation in the absorber layer. Application of 1 nm MoO3/11 nm Ag/10 nm MoO3/50 nm Alq3 multilayer electrodes in OSCs lead to an efficiency of 2.6% for a standard ZnPc:C60 cell, showing superior performance compared to devices with pure silver top contacts. The device lifetime is also strongly increased. MoO3 layers can saturate and stabilize the inner and outer metal surface, passivating it against most of the degradation mechanisms. With such an oxide/silver/oxide multilayer electrode, the time until the glass encapsulated OSC is degraded to 80% of its starting efficiency is enhanced from 86 h to approximately 4500 h compared to an OSC without an oxide interlayer.

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