Electronic Properties of Interfaces between PCPDTBT and Prototypical Electrodes Studied by Photoemission Spectroscopy

Authors

  • Umut Aygül,

    Corresponding author
    1. Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen (Germany), Fax: (+49) 7071 29 5490
    • Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen (Germany), Fax: (+49) 7071 29 5490
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  • Dr. Heiko Peisert,

    1. Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen (Germany), Fax: (+49) 7071 29 5490
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  • Johannes Frisch,

    1. Institut für Physik, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 6, 12489 Berlin (Germany)
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  • Dr. Antje Vollmer,

    1. Helmholtz-Zentrum Berlin für Materialien und Energie, Speicherring BESSY II, 12489 Berlin (Germany)
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  • Prof. Norbert Koch,

    1. Institut für Physik, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 6, 12489 Berlin (Germany)
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  • Prof. Thomas Chassé

    1. Institut für Physikalische und Theoretische Chemie, Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen (Germany), Fax: (+49) 7071 29 5490
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  • PCPDTBT: poly[2,6-(4,4-bis-(2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)]

Abstract

We report on the electronic structure of poly[2,6-(4,4-bis- (2-ethylhexyl)-4H-cyclopenta[2,1-b;3,4-b′]dithiophene)-alt-4,7(2,1,3-benzothiadiazole)] (PCPDTBT), a promising low-band-gap donor material for efficient bulk heterojunction organic solar cells. Electronic properties of interfaces formed between PCPDTBT and prototypical electrodes [Au, indium-tin-oxide and poly(ethylene-dioxythiophene): poly(styrenesulfonate)], obtained from X-ray photoemission spectroscopy and ultraviolet photoemission spectroscopy, are evaluated. The formation of interface dipoles is observed, and their consequences for device performance are discussed. For the system PCPDTBT/Au chemical interactions occur, which may affect in particular the charge extraction at the corresponding interface.

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