Electronic components made from single molecules

Electronic components built from single molecules using chemical synthesis could pave the way for smaller, faster and more green and sustainable electronic devices. Now, for the first time, a transistor made from just one molecular monolayer has been made to work where it really counts. On a computer chip.

The molecular integrated circuit was created by a group of chemists and physicists from the Department of Chemistry Nano-Science Center at the University of Copenhagen and Chinese Academy of Sciences, Beijing. The breakthrough was made possible through an innovative use of the two-dimensional carbon material graphene.

Kasper Nørgaard, associate professor in chemistry at the University of Copenhagen, believes that the first advantage of the newly developed graphene chip will be to ease the testing of coming molecular electronic components. But he is also confident that it represents a first step towards proper integrated molecular circuits.

“Graphene has some very interesting properties which cannot be matched by any other material. What we have shown for the first time is that it’s possible to integrate a functional component on a graphene chip. I honestly feel this is front page news,” says Nørgaard.

The molecular computer chip is a sandwich built with one layer of gold, one of molecular components and one of the extremely thin carbon material graphene. The molecular transistor in the sandwich is switched on and off using a light impulse so one of the peculiar properties of graphene is highly useful. Even though graphene is made of carbon, it’s almost completely translucent.

The hunt for transistors, wires, contacts and other electronic components made from single molecules has had researchers working night and day. Unlike traditional components they are expected to require no heavy metals and rare earth elements. So they should be cheaper as well as less harmful to earth, water and animals. Unfortunately, it has been extremely difficult to test how well these functional molecules work. Until now.

Using the new graphene chip, researchers can now place their molecules with great precision. This makes it faster and easier to test the functionality of molecular wires, contacts and diodes so that chemists will know in no time whether they need to get back to their beakers to develop new functional molecules, explains Nørgaard.

The researchers’ discovery, ‘Ultrathin Reduced Graphene Oxide Films as Transparent Top-Contacts for Light Switchable Solid-State Molecular Junctions’, has been published online in Advanced Materials. The work has been supported by the Danish Chinese Center for Molecular Nano-Electronics and financed by the Danish National Research Foundation, the European Union 7th framework for research (FP7) and by The Lundbeck Foundation.