Researchers from AMBER at Trinity College of Dublin have, for what it claims is the first time, fabricated printed transistors consisting entirely of graphene flakes as the electrodes along with other layered materials.
In collaboration with TU Delft in The Netherlands, the team used standard printing techniques to combine the graphene flakes with tungsten diselenide and boron nitride to create an all-printed, all-layered material, working transistor.
The development could have long-ranging impact on the potential to cheaply print a range of electronic devices from solar cells to light emitting diodes (LEDs) for applications such as interactive smart food and drug labels to new banknote security and e-passports.
“In the future, printed devices will be incorporated into even the most mundane objects such as labels, posters and packaging,” says Jonathan Coleman, professor of chemical physics at Trinity. “Printed electronic circuitry will allow consumer products to gather, process, display and transmit information: For example, milk cartons will send messages to your phone warning that the milk is about to go out-of-date.”
Coleman believes 2-D nanomaterials can compete with materials currently used for printed electronics because they are more cost effective and achieve a higher performance. The development from Trinity opens the door to print a whole host of devices solely from 2-D nanosheets.
The flakes are only a few nanometers thick but hundreds of nanometers wide that are capable of conducting (graphene), insulating (boron nitride) and semiconducting (tungsten diselenide) to enable the creation of the building blocks of electronics. While currently the printed layered devices cannot compare with advanced transistors, the hope is to improve the performance of the printed thin-film transistors beyond its current state.
The layered materials were printed using inks created using a liquid exfoliation method developed by Coleman, who later licensed it to Samsung Electronics. The liquid processing techniques yield large quantities of high-quality layered materials that helps enable the potential to print circuitry at low cost.