Researchers develop single molecule switch

Researchers at the Technische Universität München have developed a molecular nanoswitch that functions when voltage is applied. The technology could eventually serve as a replacement for silicon.

The scientists at the university started their work developing high-precision electrical contacts for molecules. They then used synthetic molecules from colleagues from Basel and Karlsruhe. These molecules change structure when voltage is applied; they become flat and conductive, and they scatter light.

The scattering of light is the result of the Raman effect and the vibrations of molecules that occur during this process can be observed using Raman spectroscopy. Previous attempts to detect voltage-based molecular switching relied on scanning at very low temperatures, but Raman spectroscopy enabled the researchers to do this at room temperature.

In addition, their method allowed them to determine that their single molecule stably switched between two structurally different states, under the influence of the voltage change. The finding is a step towards the goal of the team from the Technische Universität München to develop nanoelectronics with directly controllable molecules as an alternative to silicon-based components. “It brings us one step closer to the ultimate limit of miniaturization,” said nanoscientist Joachim Reichert of the Technical University of Munich.

The researchers detailed their findings in the paper Voltage-Driven Conformational Switching with Distinct Raman Signature in a Single-Molecule Junction, published in the Journal of the American Chemical Society.

Artist’s impression of the molecular switch