Piezoelectric Devices Research Articles

A Comparative Study of Material and Structural Configurations in Piezoelectric Energy Harvesting

The objective of this study is to evaluate the energy harvesting performance of piezoelectric cantilever beams using three configurations—unimorph, bimorph, and stack—with two piezoelectric materials, PZT-5A and PVDF. The methodology involved a detailed analysis of voltage, mechanical power, and electrical power outputs across varying frequencies and load resistances. Experiments were conducted at the resonance frequencies of each beam configuration and material to determine their energy conversion efficiency. The results reveal that PZT-5A significantly outperformed PVDF, with PZT-5A's voltage output being up to 94% higher at resonance. Among the configurations, the bimorph beam with PZT-5A demonstrated the highest energy conversion efficiency, achieving a 50% increase in electrical power output compared to the unimorph configuration and a 9% improvement over the stack configuration. Load resistance analysis also indicated optimal energy harvesting in the range of 104 Ω to 105Ω. The novelty of this research lies in its comprehensive comparison of different materials and configurations, highlighting the critical role of structural design and material properties in optimizing piezoelectric energy harvesters for low-power applications. These findings provide valuable insights for improving the efficiency of piezoelectric devices in various practical applications. Doi: 10.28991/ESJ-2025-09-01-019 Full Text: PDF

Wetting and Spreading Behaviors of Impacting Metal Droplet Regulated by 2D Ultrasonic Field.

The wetting and spreading behaviors of metal droplets on solid substrates are critical aspects of additive manufacturing. However, the inherent characteristics of metal droplets, including high surface tension, elevated viscosity, and extreme temperatures, pose significant challenges for wetting and spreading on nonwetting substrates. Herein, this work proposes a strategy that employs a two-dimensional (2D) orthogonal ultrasonic field to construct a vibration deposition substrate with radial vibration amplitude gradient, thereby enhancing the wettability and adhesive strength of impacting metal droplets ejected by a piezoelectric micro-jet device. First, a 2D ultrasonic vibration device is designed based on the combination of longitudinal vibration modes. Additionally, oblique and circular vibration trajectories are synthesized. The vibration amplitude distributions and trajectories of the deposition substrate are verified utilizing the finite element method. Subsequently, the experimental results demonstrate that the contact angle is decreased by 24.7%, the spreading diameter is increased by 10.3%, and the adhesive strength is enhanced by 5.4 times compared to deposition on a static substrate. The 2D ultrasonic field facilitates the transition of metal droplets from a non-wetting state to a wetting state on the nonwetting substrate, which highlights the versatility and adaptability of ultrasonic strategy for expanding the applications of metal droplets.

Implant stability quotient and osteogenic process in dental implant sites prepared using piezoelectric technique: A study in minipigs.

Few studies have explored the bone response in dental implant sites prepared using a piezoelectric device, indicating moderate effectiveness in enhancing secondary stability and osteogenesis. This study seeks to expand our understanding of the changes in biological, clinical, and radiographic parameters, during the initial phases of osseointegration in sites prepared with piezoelectric surgery. Two implant sites were prepared in the tibia of four minipigs. At the time of implant placement (T0), bone cortex thickness and Implant Stability Quotient (ISQ) were assessed. A bone specimen was collected from the tibia and used as the baseline for biomolecular analyses. X-ray was taken after implant insertion. After 14 days (T14), a computed tomography (CT) scan of the tibias was conducted, and ISQ values were reassessed. Histological and biomolecular analyses were performed on bone sections containing the implant. ISQ significantly increased from T0 to T14, in the absence of any correlation between the cortical thickness and ISQ. In two animals, CT showed a slight trabecular bone thickening adjacent to the implants and disorganized radiodense spots; in the other two, no trabecular osseodensification was evident. Newly formed bone was about 48% of the tissue around implants. At T14, an increase in osteogenic factors and a decrease in inflammatory molecules were observed. This study enhances understanding of the biological and clinical responses at bone implant sites following piezoelectric surgery. It highlights the relationship between the rise in certain osteogenic factors and new bone formation, as well as a potential association with increased ISQ.

Anisotropic Poly(vinylidene fluoride-co-trifluoroethylene)/MXene Aerogel-Based Piezoelectric Nanogenerator for Efficient Kinetic Energy Harvesting and Self-Powered Force Sensing Applications.

Lightweight flexible piezoelectric devices have garnered significant interest over the past few decades due to their applications as energy harvesters and wearable sensors. Among different piezoelectrically active polymers, poly(vinylidene fluoride) and its copolymers have attracted considerable attention for energy conversion due to their high flexibility, thermal stability, and biocompatibility. However, the orientation of polymer chains for self-poling under mild conditions is still a challenging task. Herein, anisotropic poly(vinylidene fluoride-co-trifluoroethylene) (PVDF-TrFE)/MXene aerogel-based piezoelectric generators with highly oriented MXene fillers are fabricated. The unidirectional freezing of a hybrid solution facilitates the strain-induced alignment of MXene nanosheets and polymer chains along the solvent crystal growth direction due to the robust interactions between the MXene nanosheets (O-H/F groups) and PVDF-TrFE chains (F-C/C-H groups). Consequently, this process fosters the development of abundant electroactive β crystals with preferred alignment characteristics, leading to the formation of intrinsic self-oriented dipoles within the PVDF-TrFE aerogel. As a result, the piezoelectric properties of PVDF-TrFE are fully harnessed without any complex poling process, resulting in an open-circuit voltage of around 40 V with MXene loading of 3 wt % in anisotropic aerogel, which is 2-fold higher than that of the corresponding isotropic aerogel where the MXene nanosheets and polymer chains are randomly aligned. Furthermore, the developed piezoelectric nanogenerator was demonstrated as a tactile sensor which showed a high sensitivity of 9.6 V/N for lower forces (less than 2 N) and a sensitivity of 1.3 V/N in the higher force regime (2 N < force < 10 N). The strategy adopted here not only provides the enhancement of the piezoelectric crystalline form for self-poling but also paves an avenue toward developing self-powered energy harvesters using piezoelectric polymers.

Optimizing High-Power Performance of [001]-Oriented Pb(Mg1/3Nb2/3)-PbTiO3 Through Combined DC and AC Polarization Above Curie Temperature

Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals (PMN-PT SCs) are widely utilized in high-performance piezoelectric devices due to their exceptional piezoelectric properties. Among the various post-processing techniques for domain engineering in PMN-PT SCs, alternating current polarization (ACP) has become a widely adopted method for enhancing piezoelectric performance. This study proposes a new ultrahigh-temperature field-cooling polarization (UFCP) technique, combining direct current polarization (DCP) and ACP with field cooling above the Curie temperature. Dielectric spectra indicate that the UFCP method promotes electric field-induced phase transitions above the Curie point, forming a stable multiphase configuration. The transverse piezoelectric coefficient d31 of UFCP SCs is 1126 pC/N, and the electromechanical coupling factor k31 is 0.559. Compared with traditional DCP, UFCP increases d31 by 68.6%, the mechanical quality factor Qm by 16.7%, and the piezoelectric figure of merit (FOM) by 98.3%. Furthermore, under high-power excitation with a root-mean-square voltage of 15 V, UFCP achieves a 343% increase in power and a 130.5% improvement in the FOM compared with DCP, demonstrating its potential for enhancing high-power performance in practical applications.

Investigation of the Dynamical Analysis, Stability, and Bifurcation for a Connected Damped Oscillator with a Piezoelectric Harvester

PurposeThe present work investigates and analyzes the mathematical modeling of a dynamical system attached to a piezoelectric device. It is well-established that piezoelectric transducers are effective energy harvesting devices commonly utilized in practical applications with mechanical systems. The structure of the dynamical model contains a damped Duffing oscillator acting as the major component, which is connected to an un-stretched pendulum and at the same time, to the piezoelectric harvester.MethodLagrange's equations are employed to deduce the governing equations of motion (EOM) based on the overall generalized coordinates characterizing the system. This model has been solved analytically using a perturbation technique known multiple-scales (MS) up to the third approximation. This indicates a level of complexity and detail in the model’s analysis. Moreover, the obtained solutions are compared with the numerical ones for more transparency and to highlight the accuracy of the approximate solutions.ResultsDetailed graphical figures have been executed to study the nonlinear stability analysis of the equations of modulation. Phase portrait diagrams, bifurcation ones, and spectrums of Lyapunov are exhibited to illustrate various types of systems’ behavior, complemented by Poincaré maps for further insight. Additionally, the varied ranges of the stabilities are explored and discussed.ApplicationsThe mechanical vibrations are converted to electricity due to the existence of the piezoelectric transducer that is connected to the dynamic model, which has wide uses and applications like crystal oscillators, medical ultrasound applications, gas igniters, and displacement transducers.

Crystal Structure Evolution of Piezoelectric Fe-Doped ZnO Film by Magnetron Co-Sputtering Technique

Zinc oxide (ZnO) exhibits piezoelectric properties due to its asymmetric structure, making it suitable for piezoelectric devices. This experiment deposited Fe-doped ZnO films on silicon substrates using a dual-target magnetron co-sputtering system. The films achieved a high c-axis orientation, and the piezoelectric coefficient of the film reached its optimal value of 44.35 pC/N when doped with 0.5 at% of Fe. This value is approximately three times that of undoped ZnO films with a piezoelectric coefficient of 13.04 pC/N. The study utilized a diffractometer, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy to evaluate the crystal structure evolution of the zinc oxide films and employed X-ray photoelectron spectroscopy to assess the valence state of the Fe ions.

Oxygen-Passivated Sulfur Vacancies in Monolayer MoS2 for Enhanced Piezoelectricity.

Modern-day applications demand onboard electricity generation that can be achieved using piezoelectric phenomena. Reducing the dimensionality of materials is a pathway to enhancing the piezoelectric properties. Transition-metal dichalcogenides have been shown to exhibit high piezoelectricity. Monolayer MoS2 possesses strong piezoelectricity that is otherwise negligible in its bulk form. The presence of sulfur vacancy defects in two-dimensional MoS2 can starkly reduce piezoelectric output due to enhanced charge screening. Oxygen passivation offers thermodynamically favorable and superior vacancy passivation. Here, we demonstrate an in situ oxygen passivation of sulfur vacancies achieved by performing chemical vapor deposition in atmospheric pressure conditions, resulting in a dramatically enhanced piezoelectric output. We achieved an out-of-plane effective piezoelectric coefficient d33eff 0.54 pm/V for the MoS2 monolayer with sulfur vacancies (SV-MoS2) and 0.94 pm/V where sulfur vacancies are passivated by oxygen (OP-MoS2). The piezoelectric device (PED) based on OP-MoS2 exhibits 26% higher output voltage than SV-MoS2 with the maximum peak-to-peak value of 0.95 V. Additionally, we show that the OP-MoS2-based PED can charge a 330 nF capacitor 30% faster than the SV-MoS2 PED for up to 50 mV in 0.5 s by repetitive finger tapping. The evolution of piezoelectricity in MoS2 with sulfur vacancy defect manipulation promises an avenue for scalable defect engineering for next-generation applications in miniaturized self-powered electronics and sensors across computing, healthcare, and size-, weight-, and power-constrained environments.

Raman activity and high electron mobility of piezoelectric semiconductor GaSiX2 (X = N, P, and As) toward flexible nanoelectronic devices

Abstract Inspired by the urgent demand for novel multifunctional materials in advanced technology applications, herein, first-principles calculations are utilized to construct new two-dimensional GaSiX 2 (X = N, P, As) monolayers. After optimizing the GaSiX 2 crystal structures, their stabilities, Raman responses, piezoelectricity, and electronic/transport characteristics are systematically studied. Results from phonon dispersions, ab initio molecular dynamics simulations, elastic constants, and cohesive energies confirm the good dynamic, thermal, energetic, and mechanical stabilities of the proposed GaSiX 2 monolayers. Based on the Heyd–Scuseria–Ernzerhof approach, the GaSiX 2 exhibit semiconductor behaviors with favorable bandgaps for absorption of the visible spectrum of 1.82 for GaSiP2 and 1.43 eV for GaSiAs2 monolayer. In addition, the GaSiX 2 monolayers also show piezoelectric effects, and high in-plane piezoelectric coefficients d 11 are found for the GaSiP2 (−1.16 pm V − 1 ) and GaSiAs2 (−1.26 pm V − 1 ). The carrier mobilities of the GaSiX 2 are estimated by the deformation potential method for their transport properties. Along two in-plane transport directions, the carrier mobilities of the GaSiX 2 are anisotropy for holes and electrons. GaSiP2 and GaSiAs2 show large electron mobilities along the x axis of 2816.99 and 1211.41 cm2V−1s−1, respectively. Thus, the GaSiP2 and GaSiAs2 monolayers not only have high anisotropic electron mobilities but also favorable bandgaps and large piezoelectric coefficients, indicating potential applications of GaSiP2 and GaSiAs2 in electronic, photovoltaic, and piezoelectric devices. The findings of this study may provide insights into the GaSiX 2 monolayers for multifunctional applications.

Strong out-of-plane piezoelectric properties in Janus PdXY (X, Y = O, S, Se, Te; X ≠ Y) monolayers: A first-principles study

The development of piezoelectric materials is limited by incomplete internal mechanisms and a lack of vertical piezoelectricity. This study introduces Janus PdXY (X, Y= O, S, Se, Te; X ≠ Y) monolayers as innovative candidates for superior piezoelectric performance, as predicted by density functional theory. Our study reveals that these materials possess exceptional in-plane and out-of-plane piezoelectric properties, with the out-of-plane coefficient d33 being up to two orders of magnitude greater than that of conventional Janus materials. This enhancement is attributed to the electron contributions and correlates with the Bader charge difference and electronegativity difference ratio, which conforms to the P-R mechanism. Additionally, the impact of layer thickness on piezoelectric coefficients is evaluated. These findings highlight the potential of Janus PdXY monolayers for advanced nanoscale flexible piezoelectric devices and offer valuable insights for the design of transition metal dichalcogenide-based Janus materials with robust out-of-plane piezoelectricity.

Self-Assembled Piezoelectric Films from Aligned Lysozyme Protein Fibrils.

Piezoelectric organic polymers are promising alternatives to their inorganic counterparts due to their mechanical flexibility, making them suitable for flexible and wearable piezoelectric devices. Biological polymers such as proteins have been reported to possess piezoelectricity, while offering additional benefits, such as biocompatibility and biodegradability. However, questions remain regarding protein piezoelectricity, such as the impact of the protein secondary structure. This study examines the piezoelectric properties of lysozyme amyloid fibril films, plasticized by polyethylene glycol (PEG). The films demonstrated a measurable d33 coefficient of 1.4 ± 0.1 pCN-1, for the optimized PEG concentration, confirming piezoelectricity. The PEG was found to hydrogen-bond with the fibrils, likely impacting the piezoelectric response of the film. Polarization imaging revealed long-range alignment of the amyloid fibrils in a circumferential arrangement. These results demonstrate the potential of using amyloid fibrils, which can be formed from various proteins, to create bulk self-assembled piezoelectric materials.

Mechanical manipulation of electromechanical fields in multi-tunnel piezoelectric semiconductor thin film devices by creating localized transverse mechanical field excitations

Mechanical manipulation of electromechanical fields in multi-tunnel piezoelectric semiconductor thin film devices by creating localized transverse mechanical field excitations

Molecular Ferroelectrics for Highly Sensitive Detection Toward Low-Frequency Sound Recognition.

Human hearing cannot sensitively detect sounds below 100Hz, which can affect the physical well-being and lead to dizziness, headaches, and nausea. Piezoelectric acoustic sensors still lack sensitivity to low-frequency sounds owing to the low piezoelectric coefficient or high elastic modulus of materials. The low elastic modulus and substantial piezoelectric coefficient of molecular ferroelectric materials make them excellent candidates for acoustic sensors. In this study, the molecular ferroelectric, [(CH3)3NCH2Cl]CdCl3, is used as a piezoelectric active layer in the construction of a piezoelectric acoustic sensor for low-frequency sound detection. The sensor exhibits high sensitivity (47.43mV Pa-1 cm-2) at 87Hz, with an excellent level of frequency resolution (up to 0.1Hz). This facilitates the accurate discrimination and detection of low-frequency sounds, which is suitable for noise detection applications. The sensor differentiates between various musical instruments and heartbeats, and recognizes audio signals. This study highlights the potential of molecular ferroelectric materials in piezoelectric acoustic device applications, including noise detection, health monitoring, and human-computer interactions.

Ultrahigh carrier mobility and multidirectional piezoelectricity in 2D Janus copper-containing chalcogenide monolayers.

Two-dimensional (2D) materials have attracted enormous research attention due to their remarkable properties and potential applications in electronic and optoelectronic devices. In this work, Janus 2D copper-containing chalcogenides, CuP2Se0.5S0.5 and CuP2Te0.5Se0.5 monolayers, are proposed and studied systematically based on first-principles calculations. These two Janus-structured materials possess the same thermal and dynamic stability as the perfect CuP2Se structure. Remarkably, we observe multiple VBM and CBM points with negligible energy differences in the band structures of perfect CuP2Se and Janus CuP2Se0.5S0.5 and CuP2Te0.5Se0.5 monolayers. This will significantly impact the electronic and transport properties of the material. The calculated anisotropic carrier mobilities can reach 104-105 cm2 V-1 s-1 orders of magnitude, which are higher than those of most reported materials. Meanwhile, the two Janus derivatives, CuP2Se0.5S0.5 and CuP2Te0.5Se0.5 monolayers, exhibit outstanding multidirectional piezoelectricity, which are comparable with those of traditional piezoelectric materials. The combination of ultrahigh carrier mobility and multidirectional piezoelectricity indicates that these novel 2D Janus materials could be promising for applications in electronic and piezoelectric devices under special conditions.

Optimizing and Enhancing Piezoelectric Energy Harvesting Devices

Optimizing and Enhancing Piezoelectric Energy Harvesting Devices

Flexible and stable piezoelectric nanogenerators based on monoclinic phase CsPbBr3 perovskite nanocrystals.

CsPbBr3 perovskite has garnered significant attention in the field of optoelectronics due to its exceptional photoelectric properties. In this study, we report the fabrication of a piezoelectric nanogenerator (PNG) composed of a composite of monoclinic phase CsPbBr3 nanocrystals and polydimethylsiloxane. This is the first instance of a PNG based on the monoclinic phase of CsPbBr3. The PNG device has been optimized to operate at a frequency of 30 Hz and exhibits impressive output performance, generating a peak-to-peak output voltage of 50 V, an output current of 5.5 μA and a power density of 2.5 μW cm-2 when subjected to an applied force of only 4.2 N over an effective area of 8 cm2. The energy generated by this PNG can be efficiently collected using capacitors with a high energy conversion efficiency of 21.7%. Furthermore, the output voltage of the PNG remains at 98.5% of its initial value after 20 days, demonstrating exceptional stability. This study highlights the great potential of CsPbBr3 perovskite materials for the simple and cost-effective fabrication of high-performance multifunctional piezoelectric energy harvesting devices.

Stacking Dependent Piezoelectric Response of Bilayer and Heterobilayer Group-IV Monochalcogenides under Applied External Strain

Layered two-dimensional (2D) materials are promising materials for piezoelectric and optoelectronic devices due to the introduction of new and interesting properties not seen in the single layers alone. In particular,...

Enhanced functionalities in flexible poly (vinylidene fluoride-trifluoroethylene)/cerium oxide doped sodium bismuth titanate [P(VDF-TrFE)/NBT-CeO2] ceramic polymer composite films: A comprehensive investigation of piezoelectric, pyroelectric, and ferroelectric properties

In the pursuit of innovative smart polymer piezoelectric ceramic composites, we present a thorough examination of the physical, structural, and polarization characteristics of a novel flexible polymer ceramic composite comprising sodium-bismuth titanate (NBT) doped with 0.6 mass % CeO2 as ceramic fillers embedded in a poly (vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) polymer matrix. The incorporation of these fillers serves to increase both the mechanical strength and functional attributes of the resulting polymer-ceramic composites. Various volume percentages of ceramic fillers were employed, and the experimental effective dielectric permittivity results were systematically fitted to established theoretical models, including Maxwell, Clausius−Mossotti, Furukawa, and effective medium theory (EMT). Our findings reveal that the composite films exhibit exceptional piezo-, pyro-, and ferroelectric properties when compared to the pristine P(VDF-TrFE) copolymer. The optimum concentration of NBT-0.6 CeO2 filler was determined to be 0.2 vol fraction resulting in a remarkable enhancement of the key parameters. Specifically, the pyroelectric coefficient increased from 32 μC/m2K to 43 μC/m2K (a ∼35 % increment), remnant polarization surged from 80 mC/m2 to 166 mC/m2 (an impressive ∼110 % increment), and the piezoelectric constant (d33) elevated from −38 pC/N to 49 pC/N (a substantial ∼30 % increment). These findings signify the potential of these optimized samples for applications in high energy density capacitors and/or highly integrated and intelligent piezoelectric devices. This comprehensive investigation not only advances our understanding of the synergistic effects within polymer-ceramic composites but also underscores the potential of the proposed material system for practical applications, providing valuable insights for the development of advanced multifunctional materials.

Surgically assisted maxillary expansion: Influence of piezosurgery on the complications linked to the midline osteotomy.

Transverse maxillary deficiency requires surgical maxillary expansion when the midpalatal suture is closed. The midline osteotomy of the maxilla can lead to significant dental, gingival and bone complications. Technically, this osteotomy is usually performed using osteotomes, a burr or an oscillating saw, but is increasingly being replaced by piezosurgery. There are no published studies on the impact of piezoelectric devices on complications. This study tries to evaluate complications after median inter-incisors osteotomy (gingival recession, tooth loss, bone loss) with piezosurgery, and then to compare them with complications associated with osteotomes. A single-center retrospective study of 57 patients who underwent surgical maxillary expansion was conducted. Dental complications (mobility, color and loss), gingival and papilla recession and bone defect were assessed before and at least 6 months after surgery. Two groups were compared: the piezosurgery P group (49 patients) and the osteotomes O group (8 patients). In piezosurgery group, 16.3 % of patients developed central papilla recession and 8 % bone defect, against 12.5 % and 0 % respectively in osteotomes group. No statistically significant difference was found between both groups in the incidence of gingival or bone complications.

Fluid-Structure Interaction Analysis of Trapezoidal and Arc-Shaped Membranes Mimicking the Organ of Corti.

In a previous study [H. Shintaku etal., Sensors and Actuators A: Physical 158 (2010): 183-192], an artificially developed auditory sensor device showed a frequency selectivity in the range from 6.6 to 19.8 kHz in air and from 1.4 to 4.9 kHz in liquid. Furthermore, the sensor succeeded in obtaining auditory brain-stem responses in deafened guinea pigs [T. Inaoka etal., Proceedings of the National Academy of Sciences of the United States of America 108 (2011): 18390-18395]. Since then, several research groups have developed piezoelectric auditory devices that have the capability of acoustic/electric conversion. However, the piezoelectric devices are required to be optimally designed with respect to the frequency range in liquids. In the present study, focusing on the trapezoidal shape of the piezoelectric membrane, the vibration characteristics are numerically and experimentally investigated. In the numerical analysis, solving a three-dimensional fluid-structure interaction problem, resonant frequencies of the trapezoidal membrane are evaluated. Herein, Young's modulus of the membrane, which is made of polyvinylidene difluoride and is different from that of bulk, is properly determined to reproduce the experimental results measured in air. Using the modified elastic modulus for the membrane, the vibration modes and resonant frequencies in liquid are in good agreement with experimental results. It is also found that the resonant characteristics of the artificial basilar membrane for guinea pigs are quantitatively reproduced, considering the fluid-structure interaction. The present numerical method predicts experimental results and is available to improve the frequency selectivity of the piezoelectric membranes for artificial cochlear devices.