A team of researchers from Iowa State University have developed a new method for treating inkjet printed graphene with a pulsed UV laser process to transform inkjet-printed graphene into a conductive, flexible material suitable for wearable or disposable technology applications.
Current methods for treating graphene can include chemical vapor deposition, which can be costly, or thermal annealing options which present the risk and potential for degradation in sensitive components due to the inability to selectively treat the graphene. However, treating the inkjet-printed, multi-layer graphene electric circuits and electrodes with a pulsed-laser process significantly improved electrical conductivity by three orders of magnitude (over traditional methods) without damage to the paper, polymers or other fragile surfaces.
Their research, “3D nanostructured inkjet printed graphene via UV-pulsed laser irradiation enables paper-based electronics and electrochemical devices”, was recently published in Nanoscale journal, issue 35. To develop the paper-based graphene, the team used single layer graphene powder dispersed in solvents, and bath and probe sonicated. Next, the ink is loaded into a printer cartridge where the piezoelectric transducer nozzle voltage has been manipulated for uniform pattern writing. The graphene is then printed onto both flexible polymide tape and cellulose paper. Finally, a computer-controlled pulsed UV laser process selectively irradiates the graphene oxide to graphene. The process changes the shape and structure of the printed graphene from flat to a raised 3D nanostructure. The result is a ridged nanostructure that subsequently increases the electrochemical reactivity of the graphene.
“This work paves the way for not only paper-based electronics with graphene circuits,” the researchers wrote in their paper, “it enables the creation of low-cost and disposable graphene-based electrochemical electrodes for myriad applications including sensors, biosensors, fuel cells and (medical) devices.”
This is the first time that a paper-based substrate as well as an inkjet printed electrode has been constructed entirely from graphene and developed for electrochemical sensing. The research is funded by a three year grant from the National Institute of Food and Agriculture as well as a three year grant from the Roy J. Carver Charitable Trust. Iowa State Research has additionally filed for a patent to this technology.