Probing the Roughness of Porphyrin Thin Films with X-ray Photoelectron Spectroscopy

Kataev E, Wechsler D, Williams FJ, Köbl J, Tsud N, Franchi S, Steinrück HP, Lytken O (2020)

Publication Type: Journal article

Publication year: 2020

Journal

DOI: 10.1002/cphc.202000568

Abstract

Thin-film growth of molecular systems is of interest for many applications, such as for instance organic electronics. In this study, we demonstrate how X-ray photoelectron spectroscopy (XPS) can be used to study the growth behavior of such molecular systems. In XPS, coverages are often calculated assuming a uniform thickness across a surface. This results in an error for rough films, and the magnitude of this error depends on the kinetic energy of the photoelectrons analyzed. We have used this kinetic-energy dependency to estimate the roughnesses of thin porphyrin films grown on rutile TiO2(110). We used two different molecules: cobalt (II) monocarboxyphenyl-10,15,20-triphenylporphyrin (CoMCTPP), with carboxylic-acid anchor groups, and cobalt (II) tetraphenylporphyrin (CoTPP), without anchor groups. We find CoMCTPP to grow as rough films at room temperature across the studied coverage range, whereas for CoTPP the first two layers remain smooth and even; depositing additional CoTPP results in rough films. Although, XPS is not a common technique for measuring roughness, it is fast and provides information of both roughness and thickness in one measurement.

Authors with CRIS profile

Involved external institutions

Universidad de Buenos Aires (UBA) / University of Buenos Aires Argentina (AR) Univerzita Karlova v Praze / Charles University in Prague Czech Republic (CZ) Istituto di struttura della materia (ISM) Italy (IT)

How to cite

APA:

Kataev, E., Wechsler, D., Williams, F.J., Köbl, J., Tsud, N., Franchi, S.,... Lytken, O. (2020). Probing the Roughness of Porphyrin Thin Films with X-ray Photoelectron Spectroscopy. ChemPhysChem. https://doi.org/10.1002/cphc.202000568

MLA:

Kataev, Elmar, et al. "Probing the Roughness of Porphyrin Thin Films with X-ray Photoelectron Spectroscopy." ChemPhysChem (2020).

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