Berlin 2015 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 7: Organic photovoltaics and electronics - mostly properties of the absorber (jointly with CPP,DS)
DS 7.1: Vortrag
Montag, 16. März 2015, 17:00–17:15, EW 202
Structural and electronic properties of planar organic heterojunction interfaces and their impact on diode characteristics — •A. Opitz1, A. Wilke1, N. Koch1,2, U. Hörmann3, W. Brütting3, R. Hansson4, and E. Moons4 — 1Humboldt-Universität zu Berlin, Germany — 2Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany — 3University of Augsburg, Germany — 4Karlstad University, Sweden
The structural and electronic properties of organic heterojunction interfaces are of paramount importance. Here two prototypical interfaces are discussed: diindenoperylene (DIP) combined with fullerene (C60) and copper-phthalocyanine combined with its perfluorinated analog. Angle dependent near edge X-ray absorption fine structure measurements were performed to determine the molecular orientation and compared to measurements of the frontier level alignment by ultraviolet photoelectron spectroscopy.
The orientation of the rod-like DIP molecules is unaffected upon deposition of spherical C60 molecules on top and vacuum level alignment appears. In contrast, cofacial lying interface layers with π-orbital stacking of the two phthalocyanines is observed together with energy level bending. These results will be related to the solar cell performance [1,2]. The combined experimental approach results in a comprehensive model of the investigated interface. The presence of a π-orbital stacking is also of interest for ground-state charge transfer.
[1] J. Wagner et al., Adv. Funct. Mater. 20 (2010) 4295.
[2] A. Opitz et al., Org. Electron. 10 (2009) 1259.