Silver electrodes provide higher conductance than gold for thiol-terminated oligosilane molecular junctions: the interfacial effect

• Published in: Physical chemistry chemical physics : PCCP Vol. 25; no. 19; pp. 13673 - 13682
• Main Authors: Wang, Minglang, Chen, Xianglin, Lu, Wenjun, Tian, Xinyue, Zhang, Guang-Ping
• Format: Journal Article
• Language: English
• Published: England Royal Society of Chemistry 17.05.2023
• Subjects: Charge transport; Configurations; Electrode materials; Electrodes; Electron tunneling; First principles; Gold; Quantum transport; Silver; Transport properties
• ISSN: 1463-9076; 1463-9084; 1463-9084
• DOI: 10.1039/d2cp06030b

The understanding of the interfacial effect on charge transport is essential in single-molecule electronics. In this study, we elucidated the transport properties of molecular junctions comprising thiol-terminated oligosilane with three to eight Si atoms and two types of Ag/Au electrode materials employing different interfacial configurations. First-principles quantum transport calculations demonstrated that the interfacial configuration determines the relative magnitude of the current between the Ag and Au electrodes, wherein the Ag monoatomic contact configuration presented a larger current than did the Au double-atom configuration. Further, the mechanism of electron tunneling from the interfacial states through the central σ channel was revealed. In contrast to Au double-atom electrodes, Ag monoatomic electrodes exhibit a higher current due to the presence of Ag-S interfacial states closer to the Fermi level. Our findings show that the interfacial configuration is a plausible way to generate the relative magnitude of current of thiol-terminated oligosilane molecular junctions with Au/Ag electrodes and provide further insight into the interfacial effect on the transport properties. The understanding of the interfacial effect on charge transport is essential in single-molecule electronics.