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Department of Engineering, ICT and Technologies for Energy and Transport Patent Title Piezoelectric device based on ZnO. Ref. CNR 10328 Assignee(s): CNR, Bercella Carbon Fiber s.r.l. CNR Institute: IMEM Main Inventor: Andrea Zappettini Countries: IT, EP, US, JP Priority date: 24/03/2014 Abstract The present invention relates to a piezoelectric device based on zinc oxide, that can be used both as a sensor and as actuator. More particularly, the present invention relates to a piezoelectric device comprising at least two crossed wires in carbon fiber, at the intersection of which is disposed a layer of zinc oxide in the form of "nanorods", in which one end of each of said wires is connected to an operating unit for measuring the electrical response of the system when this is urged by an external stress. Background The use of carbon fibers has expanded to many fields of application. Carbon fibers show exceptional mechanical property together with their extremely low weight. However there is the need to equip the structural systems based on carbon fibers with sensors able to determine the stress of the structure. The sensors normally used are not integrated into the structures and have a weight and a burden excessive. Technology In order to obtain sensors fully integrated in the structural elements, carbon fibers have been completely functionalized with nanorods of zinc oxide, a material that has piezoelectric effect in the direction of growth of the nanorods. The response signal to mechanical stress is collected by the carbon fibers themselves which are excellent electrical conductors. Advantages and Applications The advantage of this type of piezoelectric sensors is to be fully integrated within the structure based on carbon fibers. The sensitive element (zinc oxide) is present in the form of nanostructures directly on carbon fibers and there is no need of additional cabling, since the carbon fibers themselves act as conductors. These sensors can be inserted in any structural element realized with carbon fibers. Development stage Multiple devices were created at the laboratory level. The phases of the preparation are all extensible to the industrial scale. The activity of insertion of these devices in actual structural elements is in progress. Bercella srl is the exclusive licensee for automotive and racing markets. 51