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arXiv · 1208.5291

Understanding the Interface Dipole of Copper Phthalocyanine (CuPc)/C60: Theory and Experiment

Na Sai·Raluca Gearba·Andrei Dolocan·John R. Tritsch·Wai-Lun Chan·James R. Chelikowsky·Kevin Leung·Xiaoyang Zhu
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Abstract

Interface dipole determines the electronic energy alignment in donor/acceptor interfaces and plays an important role in organic photovoltaics. Here we present a study combining first principles density functional theory (DFT) with ultraviolet photoemission spectroscopy (UPS) and time-of-flight secondary ion mass spectrometry (TOF-SIMS) to investigate the interface dipole, energy level alignment, and structural properties at the interface between CuPc and C60. DFT finds a sizable interface dipole for the face-on orientation, in quantitative agreement with the UPS measurement, and rules out charge transfer as the origin of the interface dipole. Using TOF-SIMS we show that the interfacial morphology for the bilayer CuPc/C60 film is characterized by molecular intermixing, containing both the face-on and the edge-on orientation. The complementary experimental and theoretical results provide both insight into the origin of the interface dipole and direct evidence for the effect of interfacial morphology on the interface dipole.

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Na Sai, Raluca Gearba, Andrei Dolocan, John R. Tritsch, Wai-Lun Chan, James R. Chelikowsky, Kevin Leung, Xiaoyang Zhu. 2012-08-27. Understanding the Interface Dipole of Copper Phthalocyanine (CuPc)/C60: Theory and Experiment. https://doi.org/10.1021/jz300744r

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