Additive Manufacturing of Graphene for Identification and Sensing Applications

The huge growth of Internet of Things has been leading to a high demand in multipurpose radio frequency identification tags. The materials and manufacturing choices have subsequently become very essential for a lower cost and desired wireless performance. In addition, eco-friendly aspects are gaining more and more interest. This thesis investigates the possibilities of novel manufacturing methods for patterning graphene-based layer on versatile substrates. Graphene is a novel nanomaterial, which has gained a huge attraction due to extraordinary mechanical and electrical properties. In this work, graphene has been introduced as a promising candidate for environmentally-friendly and cost-effective wireless platforms. The focus of the research has been mostly on patterning and fabrication details. The used manufacturing methods are inkjet printing, doctor blade, and 3D direct writing. Additionally, required surface treatments and post treatments are investigated, which needed to be optimized according to ink and substrate materials properties. For instance, the inkjet printed graphene oxide needs annealing and a subsequent reduction process. This can be done using elevated temperature or under pulsed Xenon flashes. On the other hand, graphene inks require just one step curing process. This curing step can be carried out in a conventional oven or photonically by pulsed Xenon flashes. The results indicate that graphene inks have a great potential for fabricating antennas and RFID tags for sensing and identification applications. In this work, the graphene passive UHF RFID tags are manufactured and characterized. Then the wireless properties are evaluated which show acceptable read range values over the UHF band. In addition, the tags show excellent reliability at high humidity and harsh bending conditions. This indicates the great potential of graphene based tags in wireless identification and sensing platforms.