Performance Of Piezoelectric Devices Research Articles

Signal-amplified stretchable PVDF kirigami sensor via neutral axis modification

Stretchable sensors with smart materials now open up diversity opportunities by suggesting ways to overcome the limitations of conventional rigid sensors. The performance of piezoelectric devices is highly dependent on piezoelectric constants. Hence, materials with low piezoelectric constants hinder users to obtain signals induced by stimuli. To rectify this problem, there have been numerous efforts to increase piezoelectricity by doping additional materials or through chemical synthesis methods. These two methods have common limitations: low cost-effectiveness and inferior accessibility by scientists from diversity of fields. In this study, we suggest methods to amplify the response of a polyvinylidene fluoride (PVDF) kirigami sensor with a structural approach: neutral axis modification with a backing layer. We introduce two sensor models with a backing layer: single side and both sides backing layer models. In the former model, the backing layer is attached to the outward area of the concave bending section for stress increment; thereby the response of the sensor can be ameliorated. For the latter model, backing layers are attached on both sides; this synchronizes stress types in the concave and convex bending sections. Consequently, it aligns current movement within the sensor. These two methods are simple and the expected results are intuitive as the voltage amplitude changes proportionally to the backing layer thickness. Also, the modified sensor exhibits stable and identical responses during and after 1000 cyclic motions of stretching and releasing with an applied strain of 80%. The maximum voltage amplitude gap between the pristine and modified sensor is marked as 8.36 V, which is a 48% amplified response from the sensor without a backing layer. This method allows users to adjust the voltage response to their demands in a simple way. This modification also has the potential to be applied as a piezoelectric energy harvesting system.

Controlled Growth of Semiconducting ZnO Nanorods for Piezoelectric Energy Harvesting-Based Nanogenerators.

Zinc oxide (ZnO) nanorods have attracted considerable attention in recent years owing to their piezoelectric properties and potential applications in energy harvesting, sensing, and nanogenerators. Piezoelectric energy harvesting-based nanogenerators have emerged as promising new devices capable of converting mechanical energy into electric energy via nanoscale characterizations such as piezoresponse force microscopy (PFM). This technique was used to study the piezoresponse generated when an electric field was applied to the nanorods using a PFM probe. However, this work focuses on intensive studies that have been reported on the synthesis of ZnO nanostructures with controlled morphologies and their subsequent influence on piezoelectric nanogenerators. It is important to note that the diatomic nature of zinc oxide as a potential solid semiconductor and its electromechanical influence are the two main phenomena that drive the mechanism of any piezoelectric device. The results of our findings confirm that the performance of piezoelectric devices can be significantly improved by controlling the morphology and initial growth conditions of ZnO nanorods, particularly in terms of the magnitude of the piezoelectric coefficient factor (d33). Moreover, from this review, a proposed facile synthesis of ZnO nanorods, suitably produced to improve coupling and switchable polarization in piezoelectric devices, has been reported.

Piezoelectric Energy Harvesting Gyroscopes: Comparative Modeling and Effectiveness

Given its versatility in drawing power from many sources in the natural world, piezoelectric energy harvesting (PEH) has become increasingly popular. However, its energy harvesting capacities could be enhanced further. Here, a mathematical model that accurately simulates the dynamic behavior and energy harvested can facilitate further improvements in the performance of piezoelectric devices. One of the goals of this study is to create a dependable reduced-order model of a multi-purpose gyroscope. This model will make it possible to compute the harvested voltage and electrical power in a semi-analytical manner. The harvested voltage is often modeled as an average value across the whole electrode surface in piezoelectric devices. We propose a model which provides practical insights toward optimizing the performance of the system by considering a spatially varying electric field across the electrode surface length. Our framework allows investigation of the limits of applicability of the modeling assumptions across a range of load resistances. The differential quadrature method (DQM) provides the basis for the suggested numerical solution. The model is also employed to examine energy harvesting under various resistance loads. The newly developed spatially varying model is evaluated for open- and closed-circuit conditions and is proved to be accurate for various values of load resistance that have not previously been considered. The results show that using a spatially varying model is more versatile when modeling the performance of the piezoelectric multifunctional energy harvester. The performance may be accurately captured by the model for load resistances ranging between 103 Ω and 108 Ω. At optimum load resistance and near 65 KHz, the maximum power output predicted by the spatially varying (SV) model is 1.3 mV, 1.5 mV for the open-circuit (OC) model, and 2.1 mV for the closed circuit (CE) model. At a high-load resistance, the SV and OC models all predict the maximum power output to be 1.9 mV while the CE model predicted the maximum voltage to be 3 mV.

Research on Impedance Characterization of Triple-Layer Piezoelectric Bender

The use of piezoelectric material as transducer is prevalent. Piezoelectric bending mode element can be used for vibration energy harvesting because it can convert mechanical energy into electrical energy. In this article, electrical impedance characterization and equivalent circuit of triple-layer piezoelectric bender are discussed. Triple-layer piezoelectric bending device is fabricated, measured and modeled. This paper is aimed to explore simple but practical equivalent circuit models, expressed using electrical parameters of triple-layer piezoelectric bender and investigate the applicability of the Van Dyke circuit model and the complex circuit model in modeling the specimen’s equivalent circuit. The models produced impedance curves that closely matched the impedance measured for piezoelectric sample. The impedance characterization can provide a good understanding on the electrical behaviors of the triple layer piezoelectric bender when analyzing the performance of piezoelectric device.

The Horizontally Polarized Shear Waves in Multilayered Piezo-Composites with 2-2 Connectivity

Following the advances in structural applications, composite structures are being used commonly in transducer applications to improve acoustic, mechanical and electrical performance of piezoelectric devices. Functional composite transducers for sensors and actuators generally consist of ceramics and polymers, the disadvantage of the brittleness nature of the piezoelectric ceramics can be overcome and the structures especially good for sensing can be allowed for building up. Propagation behavior of horizontally polarized shear waves (SH-waves) in piezoelectric ceramic-polymer composites with 2-2 connectivity is taken into account. The multilayer structures are consisted of piezoelectric thin films bonded perfectly with polymeric thin films alternately. The phase velocity equations of SH-waves propagation in the piezoelectric ceramic-polymer composites with 2-2 connectivity are obtained for the cases of wave propagation in the direction perpendicular to the layering and along the layering, respectively. Filter effect of this kind of structure and the effect of volume fraction and shear modulus ratio of piezoelectric layer to polymer layer on the phase velocity are discussed in detail, respectively. One practical combination of piezoelectric thin film-polymer thin film multilayer system is chosen to carry out the numerical simulation, some basic properties of SH-waves propagation in above multilayered structures are revealed.