Single Molecule Transport for the Study of ϖ-conjugated Molecular Silicon and Germanium

Project: Research

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Silicon and germanium are ubiquitously used as key semiconductor materials in fabricating solid-state devices, and continue to be explored for creating qubits and qubit interactions in use for quantum computing. In parallel, efforts have been made in the design, synthesis, characterization, and implementation of silane and germane molecules for fabricating single molecule devices. In particular, single molecule switches and insulators have been created by use of molecules that contain silicon and germanium σ bonds, such as permethyloligosilanes, siloxanes and a bicyclo[2.2.2]octasilane moiety. Despite this progress, there remain significant gaps in such theoretical and experimental demonstrations for the π-conjugated silicon and germanium double bonds. Silicon and germanium π-conjugation, carrying delocalized charges, can provide strong electronic coupling thus opening the door to applications as tunable platforms for electrochemistry, mechanochemistry, and nanoelectronics. In addition, incorporating π-conjugated silicon and germanium wires with other σ- and π-conjugated components can achieve versatile functions and novel transport behaviors such as the ones dictated by the quantum interference effects. We therefore propose herein to study the formation, structure, electronic and thermoelectric properties of π-conjugated silicon and germanium molecules attached to metallic electrodes through an interdisciplinary approach that combines organic chemistry, physics, and engineering. Specifically, this research project focuses on rationally designing π-conjugated silenes and germenes, developing protocols for forming metal-molecule-metal junctions inside solutions under room temperature and ambient conditions, and characterizing the charge transport and thermoelectric properties of such single molecule junctions. Towards these goals, we will develop and apply custom-designed scanning tunneling microscope break junction technique, which allows us to fabricate single molecule circuit efficiently and reproducibly. The motivations for pursuing studies of π-conjugated silenes and germenes are their scientific importance and technological implications; the fundamental role that chemistry is expected to play in determining their molecular electronic properties; and the paucity of such experimental studies. By applying single molecule approaches onto silenes and germenes, we aim to uncover the structure-function relationships and ultimately design and create novel functionalities that harness molecular properties. An understanding of the smallest building blocks in nature - molecules, as well as their dynamic processes, holds promise in addressing issues that are critical in nanotechnology, electronics, energy and human health.


Project number9048247
Grant typeECS
Effective start/end date1/01/23 → …