Graphene with ultra-high electron mobility and super mechanical toughness has great development prospects in the fields of solar cells, radiators, flexible electronic devices and so on. In view of the fact that single-layer or a few layers of graphene have not been widely used, graphene based thin-film functional materials have become a new generation of flexible high conductivity thin-film materials because of their excellent conductivity, thermal conductivity and bendability in the macro state. Generally speaking, graphene film materials are three-dimensional materials prepared from one-dimensional and two-dimensional carbon materials such as single-layer or a few layers of graphene nano sheets and carbon nanotubes through the processes of spin coating, suction filtration, pressing, even ink-jet printing and 3D printing, and then use high-temperature curing for film-forming treatment. The thickness of the graphene flexible conductive film prepared in this way is usually micron level, including tens of thousands of layers of graphene. Although this kind of thin film has lost the transparency of graphene, it has obtained very excellent conductivity through the close arrangement between graphene layers, and its conductivity can be comparable to that of metal.
Introduction to achievements
Recently, the research group of Professor hedaping from the RF and microwave research center of Wuhan University of technology has designed a new environmentally friendly and low-cost paper-based flexible antenna pressure sensor using a 30mm thick multilayer graphene film with a conductivity of 106s / m. The sensor shows good radiation performance and strong stress sensing characteristics. Compared with the metal copper antenna, the graphene film flexible antenna has higher sensitivity and better stability. In addition, the graphene film flexible antenna pressure sensor also has flexible mechanical properties, reversible deformation and excellent temperature resistance.
Figure 1. characterization of graphene film and its application to antenna sensor performance
(A-C) tem, XRD and cross-sectional SEM. The illustrations are graphene oxide solution and Raman spectra, respectively.
(d) Paper based graphene antenna pressure sensor is attached to the back of the hand
(e) Normalized resonant frequency versus motion state curve
(f) Pet cornerstone graphene antenna pressure sensor attached to elbow
In practical application, the pressure sensing function can also be completed by selecting different base materials according to different test environments. Since the paper-based antenna has a higher fit with the human body than the pet based antenna, the paper-based antenna in the figure shows a more excellent frequency offset performance.
In this work, an application of graphene film into flexible antenna sensor is proposed, which realizes high sensitivity and high stability pressure sensing, and is very suitable for wearable devices, wireless strain sensing and other fields. This work provides a new idea for the research of electronic devices based on graphene, and a new functional fossil graphene material for further improving the performance of various sensors and antennas.