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Mechanism for Si-Si Bond Rupture in Single Molecule Junctions
Haixing Li1, Nathaniel T Kim2, Timothy A Su2
1Department of Applied Physics and Applied Mathematics, Columbia University , New York, New York 10027, United States.
Journal of the American Chemical Society
|December 15, 2016
Summary
We investigated voltage-induced silicon-silicon bond rupture in molecular junctions. Tunneling electrons excite vibrations, leading to bond breaking, especially when alternative conductive pathways exist.
Area of Science:
- Chemical Physics
- Materials Science
- Computational Chemistry
Background:
- Single molecule junctions offer a platform to study chemical bond stability.
- Applied voltage can induce bond rupture, providing experimental insights into molecular mechanics.
Purpose of the Study:
- To compare voltage-induced silicon-silicon (Si-Si) bond rupture in two distinct molecular backbone systems.
- To elucidate the mechanism of Si-Si bond rupture under applied voltage.
Main Methods:
- Ab initio density functional theory (DFT) calculations.
- Molecular dynamics (MD) simulations.
- Experimental study of single molecule junctions.
Main Results:
- A Si-Si backbone with an additional naphthyl pathway exhibits conductivity through the naphthyl group upon Si-Si bond rupture.
- Voltage-induced Si-Si bond rupture is facilitated by the presence of an alternative conductive pathway.
- Tunneling electrons excite molecular vibrational modes, leading to homolytic Si-Si bond rupture.
Conclusions:
- The study reveals a mechanism for voltage-induced Si-Si bond rupture driven by electron-vibration coupling.
- The presence of parallel conductive pathways significantly influences bond rupture dynamics in molecular junctions.
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