Realizing the Potential of ZnO with Alternative Non-Metallic Co-Dopants as Electrode Materials for Small Molecule Optoelectronic Devices

Authors

  • Yong Hyun Kim,

    1. Dresdner Innovationszentrum für Energieeffizienz, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden und Fraunhofer COMEDD, 01109 Dresden, Germany
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  • Jin Soo Kim,

    1. Electronic Materials Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Sungbuk-gu, Seoul 136-791, Republic of Korea
    2. Division of Materials Science and Engineering, Korea University, Anam-Dong 5-1, Sungbuk-gu, Seoul 136-701, Republic of Korea
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  • Won Mok Kim,

    Corresponding author
    1. Electronic Materials Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Sungbuk-gu, Seoul 136-791, Republic of Korea
    • Electronic Materials Research Center, Korea Institute of Science and Technology, 39-1, Hawolgok-dong, Sungbuk-gu, Seoul 136-791, Republic of Korea.
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  • Tae-Yeon Seong,

    1. Division of Materials Science and Engineering, Korea University, Anam-Dong 5-1, Sungbuk-gu, Seoul 136-701, Republic of Korea
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  • Jonghee Lee,

    1. Dresdner Innovationszentrum für Energieeffizienz, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden und Fraunhofer COMEDD, 01109 Dresden, Germany
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  • Lars Müller-Meskamp,

    Corresponding author
    1. Dresdner Innovationszentrum für Energieeffizienz, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden und Fraunhofer COMEDD, 01109 Dresden, Germany
    • Dresdner Innovationszentrum für Energieeffizienz, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden und Fraunhofer COMEDD, 01109 Dresden, Germany
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  • Karl Leo

    1. Dresdner Innovationszentrum für Energieeffizienz, Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden und Fraunhofer COMEDD, 01109 Dresden, Germany
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Abstract

High performance indium tin oxide (ITO)-free small molecule organic solar cells and organic light-emitting diodes (OLEDs) are demonstrated using optimized ZnO electrodes with alternative non-metallic co-dopants. The co-doping of hydrogen and fluorine reduces the metal content of ZnO thin films, resulting in a low absorption coefficient, a high transmittance, and a low refractive index as well as the high conductivity, which are needed for the application in organic solar cells and OLEDs. While the established metal-doped ZnO films have good electrical and optical properties, their application in organic devices is not as efficient as other alternative electrode approaches. The optimized ZnO electrodes presented here are employed in organic solar cells as well as OLEDs and allow not only the replacement of ITO, but also significantly improve the efficiency compared to lab-standard ITO. The enhanced performance is attributed to outstanding optical properties and spontaneously nanostructured surfaces of the ZnO films with non-metallic co-dopants and their straightforward integration with molecular doping technology, which avoids several common drawbacks of ZnO electrodes. The observations show that optimized ZnO films with non-metallic co-dopants are a promising and competitive electrode for low-cost and high performance organic solar cells and OLEDs.

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