Atom-thick sheets hold the key to new technologies

New technique for building microscopic nanosheets paves way for next generation electronics <em>-News</em>

Friday 4 February 2010
by Colin Smith

Scientists have developed a new technique for splitting ‘layered materials’ into atom-sized nanosheets, which could lead to advances in energy storage technologies and electronic devices, according to research published today in the journal Science.

Layered materials are man-made and there are more than 150 types including boron nitride, molybdenum disulfide and tungsten disulfide. These materials have the potential to conduct and store energy when they are split into microscopic layers called “nanosheets”. For decades, scientists have been working on methods to create nanosheets, but previous attempts have been time-consuming and resulted in the nanosheets being damaged, making them fragile and unsuitable for use.

A team of researchers have demonstrated for the first time in their study that they can make ‘nanosheets’ from layered materials, without damaging their electrical and energy storage properties. The researchers say these nanosheets could be used to develop the next generation of metallic and semi-metallic composite materials. They could also be used to make electronic devices including energy storage technologies and thermoelectric materials that can convert heat into electrical energy.

The researchers say their technique for creating nanosheets is simple, fast and inexpensive. They beleive that it could be scaled up to an industrial level, where billions of nanosheets could be produced at an hourly rate.

There are over 150 types of layered materials including boron nitride, molybdenum disulfide and tungsten disulfide.

The technique involves the scientists mixing layered material with a solvent, which is a liquid solution that dissolves substances. The solvent is subjected to high frequency sound energy from an ultrasonic probe. The combined effect of the solvent and the sound energy vibrations cause the layered material to separate into nanosheets.

The international study includes researchers from Imperial College London, the University of Oxford, Trinity College Dublin, Korea University and Texas A&M University. Dr Shane Bergin, from the Department of Chemistry at Imperial College London, who contributed to the study, says:

“It is amazing to think that something the size of atoms can have so much potential, and yet nanosheets could one day provide the basis for a whole new revolution in computing and electronics, which could rival the silicon based technology that we use today. Our study is the first step towards realising the potential of nanosheets as the building blocks for tomorrow’s technology.”

Professor David McComb, from the Department of Materials at Imperial College London, who also contributed to the research, adds: “Nanosheets could be used to advance a range of technologies: from sensors to batteries and super-strong materials. Nanosheets could also be combined with other conventional materials such as silicon to create new kinds of hybrid computing technologies.”

The research carried out at Imperial was supported by the Engineering and Physical Sciences Research Council under the Access to Nanoscience Equipment award.