Researchers from the University of Manchester, together with graphene manufacturer BGT Materials, have used compressed graphene ink to print an RF antenna measuring 14cm x 3.5mm onto a piece of paper. According to the team, the antenna performed well enough to make it practical for use in RFID tags and wireless sensors.
Graphene ink is usually made by mixing graphene flakes with a solvent, and sometimes a binder such as ethyl cellulose. Graphene ink with binders usually conducts electricity better than binder-free ink, but only after the binder material – an insulator – is broken down by annealing. However, the annealing process limits the surfaces onto which graphene ink can be printed because the high temperatures destroy materials like paper or plastic.
The research team has found a way to increase the conductivity of graphene ink without resorting to a binder. They accomplished this by first printing and drying the ink, then compressing it with a roller. Compressing the ink is said to increase graphene's conductivity by more than 50 times.
Comparing the graphene based RFID tag to those made from aluminium or copper, Xianjun Huang, a PhD candidate in Manchester's School of Electrical and Electronic Engineering, said: "Graphene based RFID tags can reduce cost significantly, thanks to a much simpler process and lower material cost."
Pic: SEM image of compressed graphene
Author
Graham Pitcher
Source: www.newelectronics.co.uk