Regensburg 2025 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 27: Molecular Electronics and Excited State Properties II

CPP 27.1: Vortrag

Mittwoch, 19. März 2025, 11:30–11:45, H38

Break-junctions beyond single-molecule conductance — •Joseph Hamill — Department of Chemistry and Nanoscience Center, University of Copenhagen, Denmark

The challenge in nanosciences is to reliably manipulate and probe objects on the atomic and molecular scale. Single-molecule break junctions cleverly integrate a single molecule into an electric circuit, enabling measurement of its thermal, electrochemical, and electrical properties. These studies explore candidates for waste heat capture, quantum information technologies, sensors, nanomedicine, and other novel materials applications. Over the past 20 years, single-molecule break junction methods have advanced to measure current, resistance, rectification, and thermopower. Despite this progress, they are not yet a staple in every chemist's toolbox like NMR spectroscopy. Recent studies using these junctions to monitor and induce chemical reactions may change this. I will present two recent studies demonstrating their sensitivity to changes in bonding chemistry and the tautomer state of single molecules in the junction. This sensitivity is unlocked through frequency domain spectroscopy using flicker noise analysis[1] and improved machine learning approaches, such as principal component analysis and k-means clustering.[2]

[1] U. Rashid, W. Bro-Jørgensen, K. Harilal, P. Sreelakshmi, R. R. Mondal, V. Chittari Pisharam, K. N. Parida, K. Geetharani, J. M. Hamill, and V. Kaliginedi. JACS, 146, 9063-9073. [2] P. Sreelakshmi, R. Mahashaya, S. Leitherer, U. Rashid, J. M. Hamill, M. Nair, P. Rajamalli, and V. Kaliginedi. JACS, 10.1021/jacs.4c12423.

Keywords: single-molecule; break junction; tautomeric switching; anchoring chemistry