Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5396700 | Journal of Electron Spectroscopy and Related Phenomena | 2009 | 5 Pages |
Abstract
The electronic structure of vacuum-sublimed layered organic heterostructures of pentacene (PEN) and fullerene (C60) on conducting polymer substrates was investigated using ultraviolet photoelectron spectroscopy (UPS). The conditions at the PEN/C60interface changed from thermodynamic non-equilibrium (i.e. the onset of the PEN highest occupied molecular orbital above the substrate Fermi-energy) for thin PEN coverages on C60 to thermodynamic equilibrium for thicker PEN coverages (i.e. Fermi-level pinning of PEN). This finding is attributed to a coverage-dependent pinhole connection of PEN through the C60 layer with the substrate. The experiments demonstrate the importance of organic thin film morphology for UPS measurements to assess the energy level alignment at organic/organic heterointerfaces.
Keywords
Related Topics
Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Steffen Duhm, Ingo Salzmann, Robert L. Johnson, Norbert Koch,