Unraveling molecular adsorption with surface raman spectroscopy: Trans -stilbene, trans, trans -distyrylbenzene, and trans -azobenzene on Ag/Ge(111)
Journal
Journal of Physical Chemistry C
Journal Volume
115
Journal Issue
2
Pages
516-520
Date Issued
2011
Author(s)
Abstract
Deposition of organic molecules on inorganic substrates is an important step in the fabrication of organic electronic devices with designated optoelectronic properties. Their interaction with the surface underneath and the interaction among themselves influence the molecular orientation of the first adsorbed layer and thus energy and charge transport properties of the grown organic films. We show that these interactions of trans-stilbene, trans,trans-distyrylbenzene, and trans-azobenzene adsorbed on Ag/Ge(111) -(√3 - √3)R30° surface are reflected on their Raman signatures. Detailed spectral analysis reveals the characteristic vibrational features corresponding to the molecules residing in the first adlayer and in the layers above, separately. The results further show that for all the three different molecular systems, the integrated intensity of the multilayer Raman signature increases linearly with the molecular coverage. This study explores potential utilization of Raman spectroscopy as a sensitive, noninvasive tool to characterize the intricate molecule-surface interaction and to quantify physisorbed molecular systems. © 2010 American Chemical Society.
Publisher
American Chemical Society
Type
journal article