Engineering the electronic structure of the CuPc/BPE-PTCDI interface by WO3 doping of CuPc

Authors

  • Corinna Hein,

    Corresponding author
    1. Surface Science Division, Institute of Materials Science, Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt, Germany
    • Phone: +49 6151 1669665, Fax: +49 6151 166308
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  • Eric Mankel,

    1. Surface Science Division, Institute of Materials Science, Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt, Germany
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  • Thomas Mayer,

    1. Surface Science Division, Institute of Materials Science, Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt, Germany
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  • Wolfram Jaegermann

    1. Surface Science Division, Institute of Materials Science, Technische Universität Darmstadt, Petersenstraße 32, 64287 Darmstadt, Germany
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Abstract

We investigate the electronic interface properties of an organic bilayer heterojunction solar cell, built of CuPc/BPE-PTCDI as donor/acceptor system. Band alignment of this interface and interface potentials were measured using synchrotron induced photoemission spectroscopy (SXPS) on stepwise deposited BPE-PTCDI on doped and non doped CuPc. Using non doped CuPc at thermodynamic equilibrium the bands bend at the interface in a direction that hinders dissociation of geminate pairs.

As a measure to form a band bending that supports geminate pair separation p-doping of CuPc is tested. As dopant WO3 was applied being a promising material for p-doping of CuPc due to its high ionization potential. At the doped CuPc/BPE-PTCDI interface the internal field is actually reversed now driving holes in CuPc and electrons in BPE-PTCDI away from the interface.

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