22 May 2017 |
World innovation news |
Materials & Manufacturing
Printing of the first graphene-based nano-transistor
Researchers from the Advanced Materials and Bio Engineering Research Foundation (AMBER) at Trinity College Dublin have produced the first printed transistor entirely from two-dimensional nanomaterial compounds. It has been known since the discovery of graphene that monolayer materials are at the heart of emerging technologies. Their mechanical, electrical and thermal characteristics allow the miniaturization and the improvement of electronic components. Fully-printed transistors, made up of interconnected networks of different types of two-dimensional nano-sheets, have represented the challenge of nanoscience for the last five years, among other things, because 2D materials have interactive properties that broaden the scope of application of this new generation of transistors, which can notably be produced at low cost.
A wide range of applications
Like all electronic components made of 2D materials, this graphene-based transistor will pave the way with its flexibility in applications in all fields ranging from the food and pharmaceutical industries to the architectural construction and manufacture of identity documents. Thanks to the mechanical properties of graphene, transistors can function as sensors in intelligent food packages that display a numerical countdown to indicate the expiry date, or labels that alert the consumer by SMS when wine is at its optimal temperature, or even window shutters that display the day’s weather forecast.
Furthermore, this advance is major because it shows that conductive, semiconductive and insulating 2D nanomaterials can be combined with complex devices. Jonathan Coleman, Senior Researcher at the School of Physics & CRANN, emphasized that his team has focused on transistor printing technologies because it sees electrical switches at the heart of tomorrow’s computing.
Future applications conceived from the theoretical design of graphene-based transistors
Exploration of the mechanical properties of graphene in AMBER laboratories
Transistor structure and manufacturing technique
Printable electronics have developed over the last few years mainly by taking advantage of the characteristics of carbon-based molecules. Although it is possible to transform these molecules into printable inks, they are sometimes unstable and there is a limit to their performance. There have been many attempts to overcome these obstacles by using other materials, such as carbon nanotubes, but these materials have also proved to underperform or have had insurmountable manufacturing constraints. For all these reasons, printed devices made of 2D materials still cannot compete with transistors on the market. The team believes that the results of this study represent a giant step towards the commercialization of monolayer material transistors. Indeed, researchers have succeeded in improving the synthesis of 2D materials by using a printable ink created by liquid-phase exfoliation, which allows the printing by spraying or by material inkjet. This printing method has been optimized in order to obtain a stratification of layers of functional 2D materials. Graphene, which plays the role of electrodes, is deposited on two other nanomaterials, namely tungsten diselenide and boron nitride (BN). The BN acts as a separator and the tungsten diselenide acts as a channel. These are the other two critical parts of the transistor. Tests have shown that this nano-transistor allows devices to withstand high currents at relatively low transmission voltages.
This study entitled, “All-printed thin-film transistors from networks of liquid-exfoliated nanosheets” was published on April 7, 2017 in the journal Science. It was written by Adam G. Kelly, Toby Hallam, Claudia Backes, Andrew Harvey, Amir Sajad Esmaeily, Ian Godwin, João Coelho, Valeria Nicolosi, Jannika Lauth, Aditya Kulkarni, Sachin Kinge, Laurens DA Siebbeles and Georg S. Duesberg. Jonathan N. Coleman. These researchers are affiliated with AMBER, the School of Chemistry at Trinity College Dublin, the Department of Chemical Engineering at the Delft University of Technology (Holland), the Materials Research & Development Division of Toyota Motor Europe (Belgium) Institute of Physics, EIT 2 of the Faculty of Electrical Engineering and Information Technology (Universität der Bundeswehr, Munich).