Molecular Electronics Offer Big Progress in Electrical Switches

Nanotechnology continues to shrink the mechanical, optical and electronic worlds. Mobile phones, wearable electronics, computers, vehicle engines, to name a few.

Physical components have dimension limits that will soon be reached unless new materials and components are developed. Say hello to the big progress offered by molecular electronics.

Scientists at Germany's Karlsruhe Institute of Technology (KIT) have created a molecular toggle switch that not only remains in the position selected, but also can be flipped as often as desired without deforming the plastic substrate. That's huge in a field historically challenged with maintaining product integrity. The molecular contact can be switched on and off mechanically and electrostatically, and as many times as one pleases.

First off, the breakthrough celebrates an advance reducing footprint, says Lukas Gerhard, a project leader in KIT's Institute of Nanotechnology.

"By replacing conventional silicon-based components, e.g. a switch, by individual molecules, future electronic circuits might be integrated on a space smaller by a factor of 100," Gerhard says.

The basic structure of the electromechanical switch consists of a few carbon atoms. Three sulfur atoms form the feet, which are fixed to a smooth gold surface. The toggle lever ends in a nitrile group with a nitrogen atom. When voltage is applied, the lever flips. The resulting electric field exerts a force on the charge of the nitrogen atom, and establishes contact with a second electrode.

The complete switch measures less than a nanometer. By comparison, the smallest structures used in semiconductor technology are 10 nm in dimension. That's big progress in the effort to scale down things, courtesy of molecular electronics.

Of course, size isn't everything, as it's said. Reliability is huge in the electrical switch industry. The toggle's operation always leads to a switching state, according to Gerhard. In other words, the contact is either open or closed. Until now, the implementation of this principle has failed often due to insufficient controllability of electric contacting of individual molecules.

As mentioned, the KIT researchers have succeeded in opening and closing such a contact between a molecule and a gold tip electrically and mechanically as often as desired, without causing plastic deformation.

Gerhard believes that progress in synthetic chemistry has resulted in the possibility of making available a large variety of billions of molecular building blocks of identical atomic design. "Their interconnection, however, requires them to be touched without being damaged," he notes.

Results of the breakthrough are reported in Nature Communications.

According to BCC Research, new technologies like the KIT researcher's will drive sustained growth in traditional markets and expansion into new ones, as well. Although the global electromechanical switch market is mature and well-established, it's expected to grow steadily through 2022 at a lofty 8.4% CAGR.

Download Electrical Switches: Technologies and Global Markets, BCC Research's August report on the electrical switch market to learn more about this robust market.