Molecular Arrangements in the First Monolayer of Cu-Phthalocyanine on In2O3(111)

Abstract

Well-ordered organic molecular layers on oxide surfaces are key for organic electronics. Using a combination of scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) we probe the structures of copper phthalocyanine (CuPc) on In2O3, a model for a prototypical transparent conductive oxide (TCO). These scanning-probe images allow the direct determination of the adsorption site and distortions of the molecules, which are corroborated by DFT calculations. Isolated CuPc molecules adsorb in a flat, slightly tilted geometry in three symmetry-equivalent configurations on the stoichiometric In2O3(111) surface. Increasing the coverage leads to densely packed 1D chains oriented along 〈1-10〉 directions, which dissolve into a highly ordered (2 × 2) superstructure upon increasing the CuPc density to ¾ per surface unit cell. At a coverage of one CuPc per surface unit cell, a densely packed (1 × 1) superstructure fully covers the surface. The molecules still assume the same site and orientation as before, but they partially overlap to accommodate the high packing density, leading to a bending of the molecules. These results are compared to the behavior of CoPc on In2O3(111). In summary, we demonstrate that a uniform first layer of metal-phthalocyanine molecules can be realized on the In2O3(111) surface when using the proper metal atom in the molecule.

Supplementary files

Article information

Article type
Paper
Submitted
02 Agd 2025
Accepted
10 Qad 2025
First published
10 Qad 2025
This article is Open Access
Creative Commons BY license

J. Mater. Chem. C, 2025, Accepted Manuscript

Molecular Arrangements in the First Monolayer of Cu-Phthalocyanine on In2O3(111)

M. A. A. Blatnik, F. Calcinelli, A. Jeindl, M. Eder, M. Schmid, J. Čechal, U. Diebold, P. A. Jacobson, O. Hofmann and M. Wagner, J. Mater. Chem. C, 2025, Accepted Manuscript , DOI: 10.1039/D5TC01394A

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