LONDON— Researchers at The University of Manchester in the United Kingdom have embedded graphene sensors into radio-frequency identification (RFID) devices to enable a battery-free, wireless, smart humidity monitor.The work targets Internet of Things (IoT) applications in manufacturing, food safety, health care, and sensitive operating environments such as nuclear waste handling.
The researchers describe their work in a paper just published in Scientific Reports. By layering graphene oxide (GO, a derivative of graphene) over graphene to create a flexible heterostructure, the team developed humidity sensors for remote monitoring with the ability to connect to any wireless network. The experimental device requires no battery source, as it harvests power from the receiver. According to the researchers, the sensors can be printed layer by layer to enable scalable mass production at very low cost.
The researchers used this electrical property of graphene oxide to create a battery-free wireless RFID humidity sensor by coating a printed graphene antenna with the GO layer. The resonance frequency as well as the backscattering phase of the GO/graphene antenna become sensitive to the surrounding humidity and can be detected by the RFID reader. The structure thus enables wireless humidity monitoring with digital identification attached to any location or item and paves the way for low-cost, efficient sensors for IoT applications.
Graphene was discovered in 2004 at The University of Manchester and was the first two-dimensional material to be isolated. It is stronger than steel, lightweight, flexible, and more conductive than copper. A host of other 2-D materials have been identified since graphene’s discovery, and the list continues to grow. By layering 2-D materials in a precisely chosen sequence to create van der Waals heterostructures, scientists have found they can fashion high-performance structures tailored to specific purposes.