Interfacial coordination interactions studied on cobalt octaethylporphyrin and cobalt tetraphenylporphyrin monolayers on Au(111)

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Details zur Publikation

Autorinnen und Autoren: Bai Y, Sekita M, Schmid M, Bischof T, Steinrück HP, Gottfried M
Zeitschrift: Physical Chemistry Chemical Physics
Verlag: Royal Society of Chemistry
Jahr der Veröffentlichung: 2010
Band: 12
Heftnummer: 17
Seitenbereich: 4336-4344
ISSN: 1463-9076
eISSN: 1463-9084


Abstract


Monolayers and multilayers of cobalt octaethylporphyrin (CoOEP), cobalt tetraphenylporphyrin (CoTPP) and the corresponding free-base porphyrins 2HOEP and 2HTPP on an Au(111) surface were investigated with X-ray and UV photoelectron spectroscopy (XPS and UPS). For CoTPP and CoOEP monolayers, the XP spectra show a characteristic splitting of the Co 2p signal, which suggests that only a fraction of the Co ions forms coordinative bonds to the Au(111) surface, while the others interact more weakly. This is a remarkable difference to previous results for CoOEP and CoTPP on Ag(111), where all Co ions in the monolayer were found to interact strongly and uniformly with the silver surface. Presumably, the lateral structural and electronic inhomogeneities of the reconstructed Au(111) surface are responsible for the more complex interaction behaviour on the gold surface. UP spectra of CoOEP and CoTPP monolayers show a new electronic state around 0.3 eV below the Fermi energy (E), i.e., at lower binding energy than in the case of Ag(111), where a strong signal appeared at 0.6 eV below E. In contrast, the free-base porphyrins 2HOEP and 2HTPP show no additional valence states in the monolayer, indicating that the Co ion plays a central role in the electronic interaction between the metal complexes and the substrate. These results have important implications for metal/organic interfaces in organic electronics or photovoltaic devices based on π-conjugated semiconducting metal complexes, because the character of the chemical bond at the interface determines important parameters such as charge injecting rates. © 2010 the Owner Societies.



FAU-Autorinnen und Autoren / FAU-Herausgeberinnen und Herausgeber

Schmid, Martin Dr.
Lehrstuhl für Physikalische Chemie II
Sekita, Michael Dr.
Lehrstuhl für Physikalische Chemie I
Steinrück, Hans-Peter Prof. Dr.
Lehrstuhl für Physikalische Chemie II


Zitierweisen

APA:
Bai, Y., Sekita, M., Schmid, M., Bischof, T., Steinrück, H.-P., & Gottfried, M. (2010). Interfacial coordination interactions studied on cobalt octaethylporphyrin and cobalt tetraphenylporphyrin monolayers on Au(111). Physical Chemistry Chemical Physics, 12(17), 4336-4344. https://dx.doi.org/10.1039/b924974p

MLA:
Bai, Yun, et al. "Interfacial coordination interactions studied on cobalt octaethylporphyrin and cobalt tetraphenylporphyrin monolayers on Au(111)." Physical Chemistry Chemical Physics 12.17 (2010): 4336-4344.

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