Topological Stone–Wales Defects Enhance Bonding and Electronic Coupling at the Graphene/Metal Interface

B. P. Klein, A. Ihle, S. R. Kachel, L. Ruppenthal, S. J. Hall, L. Sattler, S. M. Weber, J. Herritsch, A. Jaegermann, D. Ebeling, R. J. Maurer, G. Hilt, R. Tonner-Zech, A. Schirmeisen, J. M. Gottfried, ACS Nano 16, 11979-11987 (2022)

"Defects in Graphene subtly affect the structural and electronic properties. We perform a detailed joint experiment/theory investigation of molecular precursors of pristine graphene and Stone-Wales defects in graphene to assess the structural and spectroscopic changes imposed by defects."

Coexistence of carbonyl and ether groups on oxygen-terminated (110)-oriented diamond surfaces

Shayanthan Chaudhuri, Samuel J. Hall, Benedikt P. Klein, Marc Walker, Andrew J. Logsdail, Julie V. Macpherson, Reinhard J. Maurer, Communications Materials 3, 6 (2022)

"Here, we determine the oxygenation state of the (110) surface using a combination of density functional theory calculations and X-ray photoelectron spectroscopy experiments. We report the fabrication of the highest-quality (100)-oriented diamond crystal surface to date. We further propose a mechanism for the formation of the hybrid carbonyl-ether phase and rationalize its high stability. "

Core Electron Binding Energies in Solids from Periodic All-Electron Delta-Self-Consistent-Field Calculations

J. Matthias Kahk, Georg S. Michelitsch, Reinhard J. Maurer, Karsten Reuter, Johannes Lischner, J. Phys. Chem. Lett. 12, 9353-9359 (2021)

"We present an approach to calculate accurate core electron binding energies of a variety of materials based on Delta-self-consistent-field calculations that are referenced to the valence band maximum. We further show that the resulting simulations provide excellent agreement with experimental X-ray photoemission spectroscopy data."

Topology Effects in Molecular Organic Electronics Materials: Pyrene and Azupyrene

Benedikt P. Klein, Lukas Ruppenthal, Samuel J. Hall, Lars E Sattler, Sebastian M. Weber, Jan Herritsch, Andrea Jaegermann, Reinhard J. Maurer, Gerhard Hilt, and Michael Gottfried, ChemPhysChem 22, 1-10 (2021)

"Using photoelectron spectroscopy, near edge X-ray absoption fine structure spectroscopy, and density functional theory, we characterize the electronic and optical properties of pyrene and azupyrene thin films. The differences between the properties of the two compounds can be understood in terms of their different bonding topology."

The Nuts and Bolts of Ab-Initio Core-Hole Simulations for K-shell X-Ray Photoemission and Absorption Spectra

B. Klein, S. J. Hall, R. J. Maurer, J. Phys. Condens. Matter 33, 154005 (2020)

"We present the numerical and technical details of our variants of the DeltaSCF and transition potential method (coined DeltaIP-TP) to simulate XPS and NEXAFS transitions. Using exemplary molecules in gas-phase, in bulk crystals, and at metal-organic interfaces, we systematically assess how practical simulation choices affect the stability and accuracy of simulations. We particularly focus on the choice of aperiodic or periodic description of systems and how spurious charge effects in periodic calculations affect the simulation outcomes. For the benefit of practitioners in the field, we discuss sensible default choices, limitations of the methods, and future prospects."

Enhanced Bonding of Pentagon–Heptagon Defects in Graphene to Metal Surfaces: Insights from the Adsorption of Azulene and Naphthalene to Pt(111)

Benedikt P. Klein, S. Elizabeth Harman, Lukas Ruppenthal, Griffin M. Ruehl, Samuel J. Hall, Spencer J. Carey, Jan Herritsch, Martin Schmid, Reinhard J. Maurer, Ralf Tonner, Charles T. Campbell, and J. Michael Gottfried, Chem. Mater. 32, 1041-1053 (2020)

"We show here that the interface properties may be controlled by topological defects, such as the pentagon–heptagon (5–7) pairs, because of their strongly enhanced bonding to the metal. To measure the bond energy and other key properties not accessible for the embedded defects, we use azulene as a molecular model for the 5–7 defect. Comparison to its isomer naphthalene, which represents the regular graphene structure, reveals that azulene interacts more strongly with a Pt(111) surface. Using a combination of single-crystal adsorption calorimetry, x-ray photoelectron and photoabsorption spectroscopies (XPS/NEXAFS), and Density Functional Theory, we fully characterize the adsorption strength, the surface structure and surface chemistry of 5-7 defect systems on Pt(111). Our model study shows that the topology of the π-electron system strongly affects its bonding to a transition metal and thus can be utilized to tailor interface properties."

Interpretation of X-ray Absorption Spectroscopy in the Presence of Surface Hybridisation

Katharina Diller, Reinhard J. Maurer, Moritz Müller, Karsten Reuter, J. Chem. Phys. 146, 214701 (2017)

Accurate ab-initio core-level spectroscopy simulations of surface-adsorbed molecules reveal the details of surface hybridization.

Coverage-Driven Dissociation of Azobenzene on Cu(111): A Route Towards Defined Surface Functionalization

M. Willenbockel, R. J. Maurer, C. Bronner, M. Schulze, B. Stadtmüller, S. Soubatch, P. Tegeder, K. Reuter, F. S. Tautz, Chem. Commun., 51, 15324-15327 (2015)

Using X-ray Photoelectron Spectroscopy, X-ray Standing Waves and Density Functional Theory we discover a novel route towards surface functionalization by coverage-driven dissociation of Azobenzene on Cu(111)

Thiolate-Bonded Self-Assembled Monolayers on Ni(111): Bonding Strength, Structure and Stability

F. Blobner, P. N. Abufager, R. Han, J. Bauer, D. A. Duncan, R. J. Maurer, K. Reuter, P. Feulner, F. Allegretti, J. Phys. Chem. C., 119, 15455-15468 (2015)

Using X-ray Photoelectron Spectroscopy, NEXAFS and Density Functional Theory we identify the insufficient stability of halogenated self-assembled monolayers on a Ni(111) surface

Temperature-dependent templated growth of porphine thin films on the (111) facets of copper and silver

K. Diller, F. Klappenberger, F. Allegretti, A. C. Papagergiou, S. Fischer, D. A. Duncan, R. J. Maurer, J. A. Lloyd, S. Cheol Oh, K. Reuter, J. V. Barth, J. Chem. Phys. 141, 144703 (2014)

Using X-ray photoelectron spectroscopy, NEXAFS and Density Functional Theory we show the coverage dependent adlayer structure of porphine films