Piezoelectric Mode Research Articles

Aspect ratio optimization of piezoelectric extensional mode resonators for quality factor and phase noise performance enhancement

Abstract This study focuses on optimizing the resonator geometry via the aspect ratio design of a width-extensional mode resonator to improve its quality factor (Q), which is one of the critical performance parameters for resonators in either sensing (Allan deviation) or frequency reference (phase noise) applications. The proposed approach uses finite element analysis to reduce the strain energy at anchor supports by altering the resonator geometric structure, thereby reducing energy loss through anchors. Moreover, process limitations on feature sizes are used as constraints to find aspect ratios that can not only increase the Q but also reduce spurious modes near the targeted frequency. The devices were fabricated using AlN thin film piezoelectric on a substrate (TPoS) process. The simulated energy dissipation trends for specific length-to-width (L/W) ratios closely match the measured changes in the resonator Q values in vacuum. In vacuum, the highest Q-factor achieved by the device is close to 8816, with a motional resistance of a few tens of ohms. Additionally, a board-level oscillator realized using a commercial low-noise amplifier exhibits phase noise performance of −141.21 dBc Hz−1 and −164.25 dBc Hz−1 at 1 kHz and 1 MHz frequency offsets, respectively. The calculated figures of merit for these offsets are 204 and 168, respectively.

Extremely Stable, Multidirectional, All‐in‐One Piezoelectric Bending Sensor with Cycle up to Million Level

AbstractFlexible bending sensors are crucial components of flexible/wearable electronics. However, their broad application is restricted by their difficulty in sensing different bending directions and, more importantly, their significant output attenuation after long cycles. Herein, a new design of an All‐in‐One piezoelectric bending sensor is proposed, in which double‐deck, cross‐over 3D interdigital microelectrodes (silver nanowires (Ag NWs)) are embedded in a piezoelectric polymer film (poly(vinylidene fluoride‐trifluoroethylene (P(VDF‐TrFE))). The piezoelectric film with the embedded 3D microelectrodes exhibits a high anisotropy coefficient ( > 1) based on dual piezoelectric modes (d31 and d33), which renders it more sensitive to different bending directions. More importantly, the homogeneous interconnected interface and heterogeneous microinterlocked interface formed inside the sensor significantly enhance its interface mechanical properties, with at least a tensile strength of 51 MPa, a shear strength of 28 MPa, and an interfacial toughness of 300 J m−2, which are nearly two orders of magnitude greater than those of conventional sandwich architectures. The prepared All‐in‐One sensor shows an extremely stable piezoelectric output over as many as 16 00 000 bending cycles, which represents a remarkable breakthrough. Furthermore, a single sensor can be used to remotely control the multidirectional motion of a smart car, demonstrating enormous potential in practical applications.

Piezoelectric Outputs of Electrospun PVDF Web as Full-Textile Sensor at Different Mechanical Excitation Frequencies.

With the increasing application of electrospun PVDF webs in piezoelectric sensors and energy-harvesting devices, it is crucial to understand their responses under complex mechanical excitations. However, the dependence of the piezoelectric effect on mechanical excitation properties is not fully comprehended. This study aims to investigate the piezoelectric output of randomly oriented electrospun PVDF nanofiber webs fabricated through different electrospinning processes at various mechanical excitation frequencies. The electrospun PVDF web was sandwiched between two textile electrodes, and its piezoelectric output as a full-textile sensor was measured across a frequency range from 0.1 Hz to 10 Hz. The experimental results revealed that the piezoelectric output of the electrospun PVDF web exhibited a nearly linear increase at excitation frequencies below 1.0 Hz and then reached an almost constant value thereafter up to 10 Hz, which is different from the hybrid PVDF or its copolymer web. Furthermore, the dependency of the piezoelectric output on the excitation frequency was found to be influenced by the specific electrospinning process employed, which determined the crystalline structure of electrospun PVDF nanofibers. These findings suggest that determining an appropriate working frequency for randomly oriented electrospun PVDF nanofiber webs is essential before practical implementation, and the piezoelectric response mode in different mechanical activation frequency ranges can be used to detect different human physiological behaviors.

Enhanced piezoelectric performance of PVDF/MWCNTs energy harvester through a 3D-printed multimodal auxetic structure for smart security systems

Piezoelectric energy harvesters (PEHs) have attracted considerable attention over recent decades for their ability to convert mechanical energy into electrical energy. However, the current landscape is characterized by a lack of structural variety, which constrains the potential for notable performance improvements and the expansion of applications of these devices. To address these challenges, three distinct metamaterial structures are investigated through numerical simulations in this study. An auxetic, reentrant shape with carefully optimized dimensions was found as the best choice for the development of an efficient Polyvinylidene fluoride/multi-walled carbon nanotubes (PVDF/MWCNTs) PEH with optimized composition. This structure exhibits a remarkable capability to activate three different piezoelectric modes. Given it is polarization in the z-direction, the structure activates both d31 and d32 modes upon stretching in the x-direction, benefitting from the structure's negative Poisson's ratio and generating an open circuit voltage of 14.8 V. In contrast, compression in the z-direction activates the d33 mode, resulting in an open-circuit voltage of 28.2 V. This design allows the harvester to charge a 1 μF capacitor to 22 V within 260 s. The structure's feasibility is further evidenced by its fabrication using Fused Deposition Modeling (FDM) 3D printing technology. To further extend its practicality and real-world application, the PEH can be seamlessly integrated into large-scale commercial, industrial, and residential flooring, offering a novel approach to security systems. In this innovative approach, the PVDF/MWCNTs PEH converts the compressive force of footsteps into electrical signals. These signals serve as triggers for an integrated alarm system. Essentially, the electrical signal functions as a switch: its transmission acts like a closed switch that triggers the activation of the alarm system. Conversely, the absence of the signal is an open switch, indicating that no external force is acting on the tiles and a safe condition is maintained. Remarkably, the PEH can produce a voltage of 19.8 V when activated by the footsteps of a 60 kg person, demonstrating its practical utility.© 2017 Elsevier Inc. All rights reserved.

A ScAlN-based piezoelectric breathing mode dual-ring resonator with high temperature stability

In this work, a scandium-doped aluminum nitride (ScAlN)-based piezoelectric breathing mode dual-ring resonator with high temperature stability is presented. The designed resonator consists of two identical rings and a coupling straight beam in between. A combination of highly doped silicon and composite structure using silicon oxide is implemented to improve the frequency-temperature stability of the resonator. The dual-ring resonator is fabricated based on a ScAlN-based thin-film piezoelectric-on‑silicon (TPoS) platform. The measurement results show that the fabricated dual-ring resonator has a loaded quality factor (Ql) of 6889 and an insertion loss of 13.898 dB at its resonant frequency of 16.766 MHz, corresponding to a motional resistance of 395 Ω, and an unloaded quality factor (Qun) of 8681. The resonator's Qun is almost constant within the pressure range of less than 300 Pa, indicating a good process tolerance in the vacuum packaging process. With the aid of the passive temperature compensation, the reported resonator exhibits an overall frequency variation of less than ±70 ppm over the entire temperature range of 20 °C to 105 °C, which agrees well with the predicted value obtained by finite element method (FEM) analysis. Moreover, Allan deviations of the resonator-based oscillator frequency are collected.

Characterization of In‐Plane Piezoelectric Strain of Ferroelectric Thin Films by the Magnetoelectric Coupling Effect

Piezoelectric response of the ferroelectric/piezoelectric thin films is crucial for actuation of micro‐electromechanical systems (MEMS) devices as well as strain‐mediated electronic devices. Among many piezoelectric modes, longitudinal and transverse piezostrain is the most widely used. Various methods have been well established for quantitative characterization of the longitudinal piezostrain, such as laser interferometer and piezoelectric force microscopy. However, it is still a great challenge to characterize transverse piezostrain. Herein, a new method is established to characterize the transverse (in‐plane) piezostrain of ferroelectric/piezoelectric thin films by the inverse magnetoelectric (ME) coupling effect. A ferromagnetic thin film is patterned onto the ferroelectric thin film to form an artificial multiferroic heterostructure. The transverse piezostrain can transfer from the ferroelectric layer to the ferromagnetic layer and shift its ferromagnetic resonance field through the ME coupling effect. By comparing with a control sample of “bulk piezoceramic/ferromagnetic thin film” whose in‐plane piezostrain can be easily measured, the in‐plane piezostrain and piezoelectric coefficient of the ferroelectric thin films are then estimated. The in‐plane piezoelectric coefficient d31 and piezoelectric strain S31 of Pb(Zr,Ti)O3 (PZT) thin films are measured by this method. This new method will promote to fully understand the piezoelectric properties of the ferroelectric/piezoelectric thin films.

Nanoscale Study of the Polar and Electronic Properties of a Molecular Erbium(III) Complex Observed via Scanning Probe Microscopy

We successfully synthesized millimeter-sized single crystals of the molecular erbium(III) complex Er(acac)3(cphen), where acac = acetylacetonate and cphen = 5-chloro-1,10-phenanthroline. The novelty of this work stems from the exhaustive examination of the polar and electronic properties of the obtained samples at the macro-, micro-, and nanoscale levels. The single crystal X-ray diffraction method demonstrates the monoclinic (noncentrosymmetric space group P21) crystallographic structure of the synthesized samples and scanning electron microscopy exhibits the terrace–ledge morphology of the surface in erbium(III) crystals. By using the piezoelectric force microscopy mode, the origin of the polar properties and the hyperpolarizability in the synthesized samples were assigned to the internal domain structure framed by the characteristic terrace–ledge topography. The direct piezoelectric coefficient (~d33) was found to be intensely dependent on the local area and was measured in the range of 4–8 pm/V. A nanoscale study using the kelvin probe force and capacitance force (dC/dz) microscopy modes exposed the effect of the Er ions clustering in the erbium(III) complex. The PFM method applied solely to the Er ion revealed the corresponding direct piezoelectric coefficient (~d33) of about 4 pm/V. Given the maximum piezoelectric coefficient in the erbium(III) complex at 8 pm/V, we highlight the significant importance of the spatial coordination between the lanthanide ion and the ligands. The polar coordination between the lanthanide ion and the nitrogen and oxygen atoms was also corroborated by Raman spectroscopy supported by the density functional theory calculations. The obtained results can be of paramount importance for the application of molecular erbium(III) complex crystals in low-magnitude magnetic or electric field devices, which would reduce the energy consumption and speed up the processing switching in nonvolatile memory devices.

An Insight into the Wearable Technologies Based on Novel Hybrid Piezoelectric‐Triboelectric Nanogenerators

Hybrid piezoelectric‐triboelectric nanogenerators (HPTNGs) are a new energy storage device that combines the benefits of both technologies. This technology can revolutionize energy storage and bring down solar and renewable costs. HPTNGs are becoming increasingly popular in the wearable technology market due to their unique characteristics. HPTNGs feature hybrid piezoelectric and triboelectric modes, allowing them to generate electricity from low voltage and sound waves. This combination gives them a higher performance than either type of generator, making them ideal for applications such as mobile banking, health monitoring, and smart home control. This article begins with a discussion on the structural configuration of hybrid HPTNGs, followed by describing their coupling effect and applications in wearable technology. Furthermore, it also focuses on the challenges, possible solutions, and prospects of this device in the wearable industry.

Realization of high performance PZN-PT single crystal based piezoelectric flexural mode hydrophone for underwater sensor applications

In this article, attempts are made to grow large size PZN-PT single crystals using high temperature solution growth method by implementing novel bottom cooling technique. The grown crystals are oriented and poled along 〈001〉 direction and obtained larger piezoelectric strain coefficient (d33 > 2000 pm V−1) suitable for development of underwater acoustic sensor requirements. Flexural mode hydrophone is realized using the oriented PZN-PT single crystal discs. Finite element modeling is employed to examine the design of the flexural mode hydrophone and an equivalent circuit model is also applied to study its acoustic characteristic at two extreme boundary conditions like simply supported and clamped edge condition. The underwater acoustic response of the PZN-PT single crystal based flexural mode hydrophone is evaluated over the frequency range (100 Hz to 12 kHz) and its responses are compared with the FEM and equivalent circuit model results. The predicted results from FEM and equivalent circuit model are found to be in good agreement with the experimental results. The receiving sensitivity of the PZN-PT single crystal-based hydrophone is 12 dB higher than the PZT 5A based hydrophone in the frequency range of 2 kHz to 6 kHz. The fabricated PZN-PT single crystal-based hydrophone offers better performance than the conventional piezo ceramic based flexural hydrophone.

Ultrahigh‐Temperature Piezoelectric Crystal YbBa3(PO4)3 for Vibration Sensing Application

AbstractHigh‐temperature vibration sensors are of great importance for accurate monitoring of dynamic mechanical conditions in automotive, aerospace and energy‐generation‐related systems. Currently, piezoelectric crystals with ultrahigh operational temperature and good piezoelectric performance for high‐temperature sensing applications are attracting considerable attention. Herein, a novel piezoelectric crystal YbBa3(PO4)3 with cubic symmetry and a high melting point of ≈1850 °C is explored, and grown by using the Czochralski method. The temperature‐dependent behaviors of electro‐elastic constants and electrical resistivity are investigated ranging from 25 to 800 °C, where the dielectric loss of the YbBa3(PO4)3 crystal is found to be ≈15% at 800 °C. In addition, an optimal crystal cut with a pure thickness shear vibration mode is designed. The optimal crystal cut presents a good piezoelectric activity ( = 12.6 pC N−1) as well as good temperature stability. Furthermore, a high‐temperature accelerometer with shear piezoelectric mode is designed and fabricated using the YbBa3(PO4)3 crystal, and the sensing performance at elevated temperature are evaluated. The average sensitivity is found to be 1.16 pC g−1, with a small temperature deviation (≈7.7%), exhibiting a good temperature stability. All these results indicate that YbBa3(PO4)3 piezoelectric crystal is a promising candidate for high‐temperature piezoelectric sensing applications.

Dimensional Analysis of Double-Track Microstructures in a Lithium Niobate Crystal Induced by Ultrashort Laser Pulses

Double-track microstructures were induced in the bulk of a z-cut lithium niobate crystal by 1030 nm 240 fs ultrashort laser pulses with a repetition rate of 100 kHz at variable pulse energies exceeding the critical Kerr self-focusing power. The microstructure topography was characterized by atomic force microscopy in piezoelectric response mode. The spatial positions of laser-induced modification regions inside lithium niobate in the case of laser beam propagation along the crystal optical axis can be directly predicted by simple analytical expressions under the paraxial approximation. A dimensional analysis of the morphology of the double-track structures revealed that both their length and width exhibit a monotonous increase with the pulse energy. The presented results have important implications for direct laser writing technology in crystalline dielectric birefringent materials, paving the way to control the high spatial resolution by means of effective energy deposition in modified regions.

Architected Piezoelectric Metamaterial With Designable Full Nonzero Piezoelectric Coefficients

Abstract Piezoelectric metamaterials have received extensive attention in the fields of robotics, nondestructive testing, energy harvesting, etc. Natural piezoelectric ceramics possess only five nonzero piezoelectric coefficients due to the crystal symmetry of ∞mm, which has limited the development of related devices. To obtain nonzero piezoelectric coefficients, previous studies mainly focus on assembling piezoelectric ceramic units or multiphase metamaterials. However, only part of the nonzero piezoelectric coefficients or locally piezoelectric electromechanical modes are achieved. Additionally, it still remains a challenge for manipulating the piezoelectric coefficients in a wide range. In this work, full nonzero piezoelectric coefficients are obtained by symmetry breaking in the architected piezoelectric metamaterial. The piezoelectric coefficients are designable over a wide range from positive to negative through manipulating the directions of each strut for the three-dimensional architected lattice. The architected metamaterials exhibit multiple positive/inverse piezoelectric modes, including normal and shear deformation. Finally, a smart gradient architected piezoelectric metamaterial is designed to take advantage of this feature, which can sense the position of the normal and shear force. This work paves the way for the manipulation of piezoelectric metamaterial in a wide range with designable full nonzero piezoelectric coefficients, thereby enabling application potential in the fields of smart sensing and actuation.

Performance enhancement of piezoelectric bulk mode MEMS mode-matched gyroscopes based on a secondary phase feedback loop

This work investigates the performance enhancement of piezoelectric bulk mode mode-matched gyroscopes based on a secondary phase feedback loop. An independent phase feedback loop realized by a lock-in amplifier is applied on a 10 MHz multiple ports piezoelectric device to harness its effective stiffness and damping factor for better gyroscope performance. The multiple ports device is designed based on support transducer topology with eight transducer arms, some of which drive the central resonant tank into a secondary elliptical mode. Open-loop measurement with varied phase delay is adopted to carry out the best working condition (i.e. higher Q-factor, smaller frequency split). Therefore, the measured scale factor results in a 1.56 times improvement through boosting the Q-factor of the driving mode. The minimum frequency split compensated by the phase feedback could reach 13.4 ppm with a tuning phase of 60° and tuning voltage of 0.1 V. The bias instability of the proposed gyro through the help of phase feedback loop could be reduced by 2.13 times. The achievement in this work has shown that the phase feedback mechanism could indeed help to improve the performance of the resonant transducers.

Dual-Mode Flexible Sensor Based on PVDF/MXene Nanosheet/Reduced Graphene Oxide Composites for Electronic Skin

MXene materials have the metallic conductivity of transition metal carbides. Among them, Ti3C2TX with an accordion structure has great application prospects in the field of wearable devices. However, flexible wearable electronic devices face the problem of single function in practical application. Therefore, it is particularly important to study a flexible sensor with multiple functions for electronic skin. In this work, the near-field electrohydrodynamic printing (NFEP) method was proposed to prepare the composite thin film with a micro/nanofiber structure on the flexible substrate using a solution of poly(vinylidene fluoride)/MXene nanosheet/reduced graphene oxide (PMR) nanocomposites as the printing solution. A dual-mode flexible sensor for electronic skin based on the PMR nanocomposite thin film was fabricated. The flexible sensor had the detection capability of the piezoresistive mode and the piezoelectric mode. In the piezoresistive mode, the sensitivity was 29.27 kPa-1 and the response/recovery time was 36/55 ms. In the piezoelectric mode, the sensitivity was 8.84 kPa-1 and the response time was 18.2 ms. Under the synergy of the dual modes, functions that cannot be achieved by a single mode sensor can be accomplished. In the process of detecting the pressure or deformation of the object, more information is obtained, which broadens the application range of the flexible sensor. The experimental results show that the dual-mode flexible sensor has great potential in human motion monitoring and wearable electronic device applications.

Increase output of vibration energy harvester by a different piezoelectric mode and branch structure design

In this study, we improve the performance of vibration energy harvesting by adopting a different working mode of piezoelectric material. We propose a harvester that is composed of an inverted beam and a branch structure. The branch can produce an amplified inertial force under vibration and passes it to a lead zirconate titanate (PZT) sheet. The resultant force acts on the PZT sheet as a dynamic normal force, not as a dynamic flexural one in the classical harvester. This change can increase the output significantly. First, the theoretical model is established and solved. The results show that the design can induce a super-harmonic vibration and produce a large output. Then, the validation experiments are carried out. The experimental results prove the occurrence of super-harmonic vibration and show that under weak stochastic excitation the branch structure can promote the electric output significantly. For a stochastic excitation of PSD = 0.06 g2 Hz−1, the average power of the novel harvester can reach 0.344 mW by a small PZT sheet with the dimensions of . This study may provide a novel scheme in improving the vibration energy harvesting efficiency.

Miniaturized electromechanical devices with multi-vibration modes achieved by orderly stacked structure with piezoelectric strain units

Piezoelectric devices based on a variety of vibration modes are widely utilized in high-tech fields to make a conversion between mechanical and electrical energies. The excitation of single or coupled vibration modes of piezoelectric devices is mainly related to the structure and property of piezoelectric materials. However, for the generally used piezoelectric materials, e.g., lead zirconate titanate ceramics, most of piezoelectric coefficients in the piezoelectric matrix are equal to zero, resulting in many piezoelectric vibration modes cannot be excited, which hinders the design of piezoelectric devices. In this work, an orderly stacked structure with piezoelectric strain units is proposed to achieve all nonzero piezoelectric coefficients, and consequently generate artificially coupled multi-vibration modes with ultrahigh strains. As an example, an orderly stacked structure with two piezoelectric strain units stator, corresponding to 31–36 coupled vibration mode, was designed and fabricated. Based on this orderly stacked structure with two piezoelectric strain units stator, we made a miniature ultrasonic motor (5 mmLength × 1.3 mmHeight × 1.06 mmWidth). Due to the ultrahigh strain of the 31–36 coupled vibration mode, the velocity per volume of the motor reached 4.66 s−1 mm−2. Furthermore, its moving resolution is around 3 nm, which is two orders higher than that of other piezoelectric motors. This work sheds a light on optimizing the performance of state-of-the-art electromechanical devices and may inspire new devices based on multi-vibration modes.

Piezoelectric Lateral-Extensional Mode Resonators With Reconfigurable Electrode and Resonance Mode-Switching Behavior Enabled by a VO₂ Thin-Film.

This article presents the first two-port lateral-extensional mode zinc oxide (ZnO) piezoelectric resonator with a reconfigurable bottom electrode that is enabled by embedding a vanadium dioxide (VO2) thin film. The insulator-to-metal phase transition of VO2 is triggered by substrate heating that translates to abrupt changes in electric field patterns and piezoelectrically transduced modal vibrations, thus allowing mode-switching of piezoelectric resonators at specific frequencies. Finite element method (FEM) analysis was used to model the broadband frequency response, while frequency characteristics of the corresponding two-port resonator were measured over a temperature range between 20 °C and 95 °C with a specific focus on two resonances at 88 and 148 MHz. By leveraging the hysteretic behavior of VO2 thin film during a heating/cooling cycle, a change in both the capacitive feedthrough and resonance signal levels was observed, due to the abrupt change in the conductivity of VO2 during its phase transition. The unique switch- ON behavior of the resonance at 88 MHz starts at 70 °C during the heating cycle, while the switch- OFF transition begins at 60 °C during the cooling cycle. On the other hand, when the temperature is increased from 20 °C to 60 °C, a decrease in the insertion loss and resonance frequency of 12 dB and 0.28 MHz, respectively, were observed for the resonance at 148 MHz. Meanwhile, a resonance frequency increase of 0.42 MHz was observed during a temperature increase from 60 °C to 95 °C, which can be ascribed to VO2 phase transition from monoclinic to rutile phase. The hysteresis loops for insertion loss and resonance frequency indicate a different critical temperature for phase transition from the monoclinic (insulator) phase and rutile (metallic) phase and vice versa. The substantial variation in the temperature coefficient of frequency can be largely ascribed to electrode reconfiguration enabled by VO2 phase transition.

Lamb waves-based technologies for structural health monitoring of composite structures for aircraft applications

The most common researched area of damage in a composite material such as carbon fibre reinforced plastics (CFRP) used currently in aircraft construction is barely visible impact damage (BVID), significantly reducing mechanical properties. Early detection and qualification would improve safety and reduce the cost of repair. In this context, structural health monitoring (SHM) techniques have been developed that could monitor a structure at any time by using a network of sensors. Widely used discrete ceramic transducers can generate and sense Lamb waves travelling in the structure. Wave propagation must then be analysed for effective damage identification. An effective SHM system is desired to meet several demands, such as minimised weight penalty, non-intrusive system not interfering with the structure performance, cost-effectiveness for implementation with targeted sensitivity and area coverage, capability of monitoring non-accessible and critical hot spot regions, robustness, and reliability. This review starts with an introduction on Lamb waves fundamentals and their use in SHM, and then particularly focuses on methods using piezoelectric transducers and mode selection. Some relevant applications on different structural configurations are discussed. Finally, recent developments on piezoelectric coating and direct-write sensor technology for tailored transducers are highlighted with some thoughts for near future research work.

Vibration analysis of piezoelectric Kirchhoff–Love shells based on Catmull–Clark subdivision surfaces

AbstractAn isogeometric Galerkin approach for analysing the free vibrations of piezoelectric shells is presented. The shell kinematics is specialized to infinitesimal deformations and follow the Kirchhoff–Love hypothesis. Both the geometry and physical fields are discretized using Catmull–Clark subdivision bases. This provides the required ‐continuous discretization for the Kirchhoff–Love theory. The crystalline structure of piezoelectric materials is described using an anisotropic constitutive relation. Hamilton's variational principle is applied to the dynamic analysis to derive the weak form of the governing equations. The coupled eigenvalue problem is formulated by considering the problem of harmonic vibration in the absence of external load. The formulation for the purely elastic case is verified using a spherical thin shell benchmark. Thereafter, the piezoelectric shell formulation is verified using a one dimensional piezoelectric beam. The piezoelectric effect and vibration modes of a transverse isotropic curved plate are analyzed and evaluated for the Scordelis–Lo roof problem. Finally, the eigenvalue analysis of a CAD model of a piezoelectric speaker shell structure showcases the ability of the proposed method to handle complex geometries.

Electromechanical Performance of Biocompatible Piezoelectric Thin-Films

The present study analyzed a computational model to evaluate the electromechanical properties of the AlN, BaTiO3, ZnO, PVDF, and KNN-NTK thin-films. With the rise in sustainable energy options for health monitoring devices and smart wearable sensors, developers need a scale to compare the popular biocompatible piezoelectric materials. Cantilever-based energy harvesting technologies are seldom used in sophisticated and efficient biosensors. Such approaches only study transverse sensor loading and are confined to fewer excitation models than real-world applications. The present research analyses transverse vibratory and axial-loading responses to help design such sensors. A thin-film strip (50 × 20 × 0.1 mm) of each sample was examined under volumetric body load stimulation and time-based axial displacement in both the d31 and d33 piezoelectric energy generation modes. By collecting evidence from the literature of the material performance, properties, and performing a validated finite element study to evaluate these performances, the study compared them with lead-based non-biocompatible materials such as PZT and PMN-PT under comparable boundary conditions. Based on the present study, biocompatible materials are swiftly catching up to their predecessors. However, there is still a significant voltage and power output performance disparity that may be difficult to close based on the method of excitation (i.e., transverse, axial, or shear. According to this study, BaTiO3 and PVDF are recommended for cantilever-based energy harvester setups and axially-loaded configurations.