Please use this identifier to cite or link to this item:
|Title:||Molecular orientation-dependent ionization potential of organic thin films|
|Authors:||Chen, W. |
|Citation:||Chen, W., Huang, H., Chen, S., Huang, Y.L., Gao, X.Y., Wee, A.T.S. (2008-11-25). Molecular orientation-dependent ionization potential of organic thin films. Chemistry of Materials 20 (22) : 7017-7021. ScholarBank@NUS Repository. https://doi.org/10.1021/cm8016352|
|Abstract:||Orientation-dependent ionization potentials (IPs) of organic thin films have been investigated with the combination of synchrotron-based high-resolution photoemission spectroscopy and near-edge X-ray absorption fine structure measurements. Organic thin films of copper(II) phthalocyanine (CuPc) and its fully fluorinated counterpart of copper hexadecafluorophthalocyanine (Fi 16CuPc) with well-controlled orientation are used as model systems. Both molecules lie flat on the graphite surface and stand upright on Au(111) terminated by self-assembled monolayer of octane-1-thiol. The IP for the standing-up CuPc thin film (IP = 4.75 eV) is 0.40 eV lower than that of the lying-down film (IP = 5.15 eV). In contrast, the IP of the standing up F 16CuPc (EP = 6.50 eV) is 0.85 eV higher than that of the lying-down film (IP = 5.65 eV). This reversed orientation dependence in IP is explained by the opposite surface dipoles in the standing-up CuPc and F16CuPc molecular layers originating from the different intramolecular dipolar bonds exposed at the surfaces, i.e., a net upward pointing surface dipole in the standing-up CuPc thin film that lowers the IP, and a net downward pointing surface dipole in the standing-up F16CuPc thin film that increases the IP. © 2008 American Chemical Society.|
|Source Title:||Chemistry of Materials|
|Appears in Collections:||Staff Publications|
Show full item record
Files in This Item:
There are no files associated with this item.
checked on May 23, 2018
WEB OF SCIENCETM
checked on May 8, 2018
checked on May 18, 2018
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.