Validating the Interfacial Electronic Structure of Molecules at High Voltages and Temperature Gradients

The electronic structure at the molecule-electrode interface is fundamental in determining the performance and stability of molecular and organic electronic devices. Traditionally, these interfaces have been studied using electrical current characterization at low or moderate voltage ranges. While this approach has provided valuable insights into the energy landscape across molecule-electrode interfaces, it has also constrained our thinking within the confines of shallow energy levels and the Landauer picture. In this presentation, we introduce our recent efforts to move beyond these limitations and explore the interfacial electronic structure under high voltage and temperature gradients. By thinking outside the conventional framework, we have developed methodologies that offer a more comprehensive view of the interfacial electronic structure. Our approach begins with the use of supramolecular-engineered monolayers, which exhibit exceptional electrical stability. This robustness enables the study of bias-function relationships across an unprecedentedly large voltage range, revealing new aspects of quantum transport behavior. Additionally, we have developed a novel junction technique to investigate the Seebeck effect in molecular tunnel junctions under various temperature differentials. This allows for a deeper analysis of the interfacial electronic structure, particularly the shape of transmission resonance peaks near the Fermi level. By combining these techniques, we significantly advance our understanding of the interfacial electronic structure in molecular systems, providing new insights into charge transport and stability that were previously obscured by traditional low-voltage investigations.