Bernal scientists together with scientists from, National University of Singapore and University of Central Florida have shown for the first time that "molecular electronic" devices can perform just as well as traditional silicon-based devices. Their report is published online at Nature Nanotechnology https://phys.org/news/2017-07-molecular-electronics-scientists-shatter-impossible.html
Until now, even the best molecular devices displayed only modest "rectification ratios", which are a measure of how good the device is at switching between ON and OFF states. Molecular devices managed at most ratios of a few thousand compared with millions for silicon. So, while these organic devices had huge potential applications, they never fully switched off, meaning they wasted current and were far less reliable than conventional electronic devices. The new finding that molecular devices can in fact switch current as effectively as silicon solves a long-standing problem that has been a major stumbling block to technology development. The scientists are hopeful that this breakthrough will advance fields such as electrically-stimulated repair of nerve tissue, which require highly reliable "soft" molecular-based devices that can interact at the sub-cellular level.
Bernal Institute scientist Dr Damien Thompson, who modelled the physics behind the devices in Science Foundation Ireland-funded work, explains that the computer simulations, performed at the Irish Center for High-End Computing, revealed that electrostatic "binding" between the molecules and the metal contacts creates a massive population of charge conduits in the device. Far higher than previously thought possible, this in turn allows the devices to perform thousands of times better than before, finally making them competitive with conventional existing technology. Damien explains: "It's not that electrostatics is a new idea, we all know intuitively that opposites attract, and the maths was worked out for charged atoms over 200 years ago. We just simply never appreciated how using it as a switching force could ramp up the number of charge carriers to the point that the devices behaved as well as silicon." Going forward, the team plan to continue seeking new ways to develop next generation type devices and device components that will permit scaling all the way down to feature sizes no bigger than atoms. Damien concludes: "The internet of things will need lots of very small, very smart things. Designing, making, and integrating these will keep a lot of scientists very busy for the foreseeable future and will advance our everyday lives in ways we are only beginning to comprehend."