Sensitive Piezoresistive sensors made of Graphene-based 3D ordered porous structures for wearable electronics

Recent years have shown significant progress in the development of stretchable electrodes, which remain the fundamental building block in flexible and wearable electronic devices. The excellent properties of graphene have made it the best candidate for the next generation of flexible electronics applications. Wearable sensors require several properties such as high flexibility, stretchability, lightweight, and inexpensive fabrication, and they must be suitable for integration with electrical components. One solution is the combination of nanostructures that act as sensors and polymers that guarantee the flexibility of the device. Different methods have been proposed in the literature to achieve these essential properties. However, all techniques develop a flexible sensor that is completely enclosed by the polymer, which reduces the effect of external stimuli, limiting the sensitivity of graphene. In order to improve the sensitivity of the piezoresistive system, we present a device in which the 3D polymer skeleton is covered by graphene layers grown by the CVD method, as shown in Figure 1a. We investigated the electrical and mechanical properties of the graphene/polymer 3D structures by measuring their electrical resistance variation as a function of compressive and tensile strain. In this presentation, we will present the optimized methodology to produce these materials and discuss the results obtained. Moreover, the realization of a piezoelectric sensor with an exposed graphene surface would be useful for several applications, such as biosensing, where the device would also be sensitive to external analytes.