Oxygen-terminated copper tips for high-resolution atomic force microscopy: From hydrogen bonds to 2D carbon nitride nano-materials

• Applicant: Privatdozent Dr. Harry Mönig
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 519972808

Gaining control on the chemical identity of the tip-terminating atom or molecule in noncontact atomic force microscopy (NC-AFM) constitutes a milestone for investigations about the chemistry of organic nano-materials. Such tip-functionalization procedures provide access to the repulsive force regime where a drastically increased resolution is obtained. Previously, we characterized the beneficial imaging properties of O-terminated Cu-tips (CuOx-tips). We could show that their high structural stability solves issues due to tip flexibility and related imaging artefacts, which are found for other established tip-functionalization approaches. The present project shifts the emphasis from tip characterization toward applications of CuOx-tips to address urging questions in surface chemistry. The planned research is structured in 2 focus areas: (1) Imaging of hydrogen bonds in molecular assemblies to explore the limits of interpretation in such data; (2) Characterization of carbon nitride nano-materials whose heterogeneous structures involve hydrogen bonds and a large variety of conformational details. Here, CuOx-tip imaging will allow minimizing artefacts related to the expected strongly varying lateral potential on these materials. The results from this project will set a profound basis for the interpretation of H-bond signatures in NC-AFM data and will establish 2D carbon nitride model systems as an important step toward a fundamental understanding of reactive sites and catalytic processes on these technologically highly relevant materials.

• DFG Programme: Research Grants