Scientists Close In On A Single-Molecule Diode

Researchers at Columbia University School of Engineering have developed a technique creating working diodes that consist of only a single molecule. These molecular diodes are capable of performing 50 times better than previous incarnations of nanoscale diodes. The research group, led by associate professor of applied physics, Latha Venkataraman, could be the first single-molecule diode that is efficient enough to have real-world applications, like incorporation into other nanoscale devices. The new discovery is detailed in the article published in the journal Nature Nanotechnology.

Previously, we've covered ever-shrinking motherboards, processing chips, and micro-batteries which could hasten the development of IoT-capable devices. An electrical diode the size of a single molecule is more than a step forward, it's a giant leap–one that has eluded nanoscale projects for some time. The idea that a molecule could act as a one-way electric conductor, or rectifier, was first theorized in 1974.

Previous molecular diodes used an asymmetrical structure to induce asymmetrical, one-way electric current; but, their ratio of "on" current to "off" current (rectification ratio) was too low to be considered effective. Venkataraman's group used environmental asymmetry instead of molecular symmetry. Specifically, they surrounded the molecular diode with an ionic solution and various-sized gold electrodes, creating asymmetry at the molecular-environmental junction.

The molecular diode creates a current of 0.1 microamps, which, although it sounds small, is actually a high current to pass through a single molecule. According to Venkataraman, the discovery is easy to replicate, and it has future applications in nanoscale devices, like graphene and carbon nanotube structures.

Source: Science Daily