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High-frequency ultrasound plays a vital role in ultrasonic imaging and particle manipulation. However, the control of high-frequency ultrasound fields with traditional acoustic lens presents challenges in impedance matching, precise control, material selection. Therefore, piezoelectric ultrasonic transducers prepared based on traditional methods are difficult to achieve high frequency and efficient sound beam control. To address these challenges, we have developed a piezoelectric metasurface-based ultrasonic transducer, using the encode binary information method to modulate acoustic waves. Simulation results reveal that at a frequency of 50 MHz, the system exhibits efficient acoustic focusing capabilities, which have been successfully applied in the experimental trapping of microspheres with acoustic tweezers. The design and development of high-frequency ultrasound transducers have emerged as a burgeoning research area at the confluence of acoustics and numerous interdisciplinary fields. [ABSTRACT FROM AUTHOR]

Advanced ferroelectrics with a combination of large piezoelectric response and good temperature stability are crucial for high sensitivity and reliability in sensing and actuating devices. However, these two key factors usually do not cooperate with each other especially for lead-free piezoelectric materials, while achieving high piezoelectricity is normally accompanied by poor stability or vice versa. Herein, we report an approach to resolve the incompatibility between piezoelectric coefficient and temperature stability by designing laminated compositions and controlling element diffusion at multi-interfaces, leading to giant piezoelectricity (d 33 ∼450 pC/N) with a minimal variation of about 7 % over a wide temperature range (25°C–90 °C), exceeding the classical lead-free systems. By elaborately modulating the diffusion conditions, the concentration of the element shows a gradually change across the laminated structure, contrast to the terraced distribution of element concentration in traditional laminated structure. Further structure characterization clarifies that the gradually change element concentration contributes to a smooth evolution of crystal structure, which is beneficial for the transition of domain switching between different composition layers, resulting in the improvement of piezoelectric temperature stability. The piezoelectric accelerometer manufactured by modulated ceramics was tested by a vibration system and turned out to be temperature stable compared with commercial PZT-4 sensor. This finding provides an effective and straightforward approach for developing superior ferroelectrics with enhanced temperature stability and high piezoelectric coefficient, promising the potential applications of piezoelectric devices concurrently approaching exceptional sensitivity and thermal reliability. [ABSTRACT FROM AUTHOR]

CaBi 4 Ti 4 O 15 (CBT) ceramics are promising piezoelectric materials that have been widely studied for high-temperature applications. Despite significant advancements in the electrical performance of CBT ceramics, the understanding of their mechanical behaviors remains limited, which is unfavorable for designing ceramics with high stability and reliability during high-temperature service. This work investigated the mechanical properties and fracture behaviors of Nb/Mn co-doped CaBi 4 Ti 4 O 15 (CBTNM) with various doping levels, focusing on stress-strain responses and ferroelastic deformation behaviors under uniaxial compression and multi-field coupling conditions. HRTEM analysis reveals small-scale layered domain wall structures on the surface of plate-like grains. The fracture and compressive strengths of CBTNM ceramics initially decrease and then increase with an increase in doping content, and the underlying mechanisms are related to grain size, defects, and densification. CBTNM ceramics exhibit nonlinear stress-strain responses due to ferroelastic deformation under compressive loading, and the resultant irreversible domain switching strain increases with an increase in doping content, while poling can further increase the residual strain. Under multi-field loading conditions, CBTNM ceramics undergo more ferroelastic deformation events and exhibit larger residual strain. The micro-cracks, pores, complicated fracture modes, and degraded fracture surfaces with fragmental and rough features are mainly responsible for the lower elastic modulus and inferior mechanical response. This work enhances our understanding of the mechanical behaviors of high-temperature piezoelectric ceramics and provides guidance for designing high-performance piezoelectric materials for complex environmental applications. [ABSTRACT FROM AUTHOR]

Antimicrobial materials are crucial for high‐touch surfaces to prevent the adhesion and proliferation of microorganisms, playing a key role in infection control measures. In this work, a magnetoelectric nanocomposite able to exert antimicrobial activity when magnetically stimulated, is obtained by solvent casting. The nanocomposites, composed of poly(hydroxybutyrate‐co‐hydroxyvalerate) (PHBV) and cobalt ferrite magnetostrictive nanoparticles (CFO NPs), respond to a variable magnetic field by mechanically stimulating the piezoelectric component of the material, thereby inducing an electrical polarization. The antimicrobial properties of the material are determined by exposing it to different frequencies (0.3 and 1 Hz) using a custom‐designed magnetic bioreactor, where the resulting electrical microenvironments are the contributing factor. The growth of Escherichia coli and Staphylococcus aureus over the nanocomposite is highly inhibited when magnetically stimulated (dynamic conditions) mainly at 0.3 Hz, in contrast to static conditions. The electric microenvironment is further measured upon magnetic stimulation, with PHBV films with 20% CFO inducing a voltage variation of ≈20 µV at the surface while the films with 10% CFO induced a voltage variation of ≈12 µV. This work demonstrated that magnetic stimulation, combined with magnetoelectric materials, can be used for remote antimicrobial control, thus preventing the spread of infections. [ABSTRACT FROM AUTHOR]

Energy harvesting from natural sources, including bodily movements, vehicle engine vibrations, and ocean waves, poses challenges due to the broad range of frequency bands involved. Piezoelectric materials are frequently used in energy harvesters, although their effectiveness depends on aligning the device's natural frequency with the frequency of the target energy source. This study models energy harvesters customized for specific applications by adjusting their natural frequencies to match the required bandwidth. We evaluate commercially available piezoelectric transducers and model them using COMSOL Multiphysics alongside an equivalent spring-mass schematic approach, enabling precise adjustments to optimize energy capture. The proposed system achieves a maximum power output of 160 µW and a power density of 187.35 µW/ cm 3 at a natural frequency of 65 Hz. Furthermore, the theoretical maximum power density is calculated as 692.97 W/ m 3 , demonstrating the system's potential for high energy efficiency under optimal conditions. Simulations are validated against experimental data to ensure accuracy. Our findings provide a design framework for optimizing energy harvester performance across diverse energy sources, leading to more efficient and application-specific devices for varied environmental conditions. [ABSTRACT FROM AUTHOR]

Integrally bladed disks (blisks) are extensively used in military and commercial aircraft engines. There are inevitable deviations between blades called mistuning, leading to the vibration localization of blisks, which potentially results in high cycle fatigue (HCF). Furthermore, the dynamic performance is sensitive to mistuning patterns. Hence, to predict the vibration response of mistuned blisks accurately, the mistuning pattern needs to be identified experimentally and verified under traveling wave excitation (TWE). Piezoelectric TWE is a promising testing technique for blisk dynamics in a non-rotating state, offering advantages such as high excitation force, wide bandwidth, and a simple setup. However, piezoelectric materials are generally arranged on blades forming an electromechanically coupled structure, which challenges the existing mistuning identification methods. In this paper, an integral mistuning identification and model updating method with traveling wave excitation verification is developed. The detuning strategy is used to split natural frequencies of blades, whereupon the response is measured blade by blade. Measured response functions of isolated blades can be retrieved by data reconstruction. Then, the mistuning patterns of elastic modulus and damping ratio are identified by Kirchhoff-plate theory and half-power bandwidth method, respectively. Experimental studies are carried out to validate the method. A dummy blisk with piezoelectric patches is designed and the dynamic properties are calculated. Blade-by-blade measurement and TWE test are conducted. Results show that natural frequencies of the updated model are in excellent agreement with the measured ones. Under TWE, the deviations of natural frequencies for all blades are less than 0.25%. The response deviation of the updated model is decreased by 89.4% on average compared with the original model and the average response deviation of the updated model is 7.4%. [ABSTRACT FROM AUTHOR]

The applications of piezoelectric materials in the field of smart structures have received significant attention from both the communities of science and engineering. Numerous experimental studies have been carried out to endow smart structures with good flexibility. The flexible/stretchable piezoelectric materials are developed to fit this emerging trend. Generally, these materials undergo significant deformation before reaching fracture failure, and they often exhibit a stress-softening phenomenon during the deformation process. However, the traditional linear constitutive model, typically used for rigid piezoelectric ceramics, continues to dominate theoretical and modeling processes in many scenarios. Existing nonlinear constitutive models usually introduce additional coefficients besides elastic, piezoelectric, and dielectric coefficients. Determining these coefficients requires a substantial number of experiments. In this work, based on a Neo-Hookean material model and electromechanical theory, a novel model for flexible piezoelectric material considering large deformation has been established. In contrast with existing models, the present model describes the nonlinear behavior of flexible piezoelectric material without the need for introducing additional parameters. Furthermore, this model exhibits a quadratic dependence of stress on the electric field. To facilitate practical applications, the constitutive model has been implemented using the commercial simulation software ABAQUS through a user subroutine. The accuracy of the subroutine is validated by comparing simulations with analytical solutions for uniaxial stretching of a flexible piezoelectric ribbon. Several numerical examples are followed to demonstrate the robustness of the elements. The proposed model offers a valuable tool for the analysis and design of flexible piezoelectric material. [ABSTRACT FROM AUTHOR]

Defect chemistry that results in the thermal processing of dielectric and piezoelectric films, crystals and ceramics ultimately controls the properties and long‐term performance of materials and devices. This paper reviews several thermochemical defect reactions using important perovskite base composition dielectrics including Pb(Zr,Ti)O3, (Na,K)NbO3, (Bi0.5Na0.5)TiO3‒BaTiO3, and Ca(Hf,Ti,Mn)O3. Within this group of perovskite‐based functional materials, we note ways the point defects can be formed to create non‐stoichiometric compositions changing the overall cation‐to‐anion ratios during the synthesis process. These reactions can be developed with the loss of volatile species such as metal and oxygen ions. The relative concentrations of these can impact the over conductions in terms of the mixed contributions of ionic conductivity from the oxygen vacancies and the electronic conductivity, along with microstructure and properties in some cases. [ABSTRACT FROM AUTHOR]

Despite the significant advancements in piezoelectric materials for sonodynamic therapy (SDT), the suppression of orthotopic glioma remains challenging, primarily due to the unclear mechanism and the restriction of blood-brain barrier (BBB). Herein, we proposed that layered piezoelectric SrBi 2 Ta 2 O 9 nanoparticles (SBTO NPs) could effectively depolarize the mitochondrial membrane potential (ΔΨ m) of glioma cells under ultrasound (US) exposure. The US-induced band bending in SBTO NPs enhanced redox ability, promoting an increase in reactive oxygen species (ROS) generation. The in vitro results proved that SBTO NPs selectively accumulated in mitochondria under US and induced apoptosis in a mitochondrial depolarization manner mediated by the generation of ROS and free charges. Furthermore, SBTO NPs could cross the BBB and then accumulate in gliomas through US/microbubbles (MBs) procedure and protein-mediated transport. The therapeutic effect of piezoelectric SBTO NPs mediated SDT was proved in the orthotopic glioma mouse model. As validated by the histopathological observation and the long-term evaluation, the good biocompatibility and biosafety of SBTO NPs make it possible for deep tumor therapy, and worthy for further preclinical study. Employing piezoelectric sonosensitizers for sonodynamic therapy (SDT) has emerged as a promising strategy for cancer treatment; however, the unclear mechanism and blood-brain barrier (BBB) limit the effectiveness of SDT in glioma. Herein, we developed piezoelectric SrBi 2 Ta 2 O 9 nanoparticles (SBTO NPs) with a built-in electric field for glioma treatment and explored the underlying therapeutic mechanism. Notably, SBTO NPs selectively accumulated in mitochondria under ultrasound (US) and induced apoptosis in a mitochondrial depolarization manner, which is mediated by the generation of reactive oxygen species (ROS) and free charges. In an orthotopic glioma mouse model, SBTO NPs were delivered into the glioma through US/microbubbles and transferrin-mediated transport pathways, inhibiting tumor growth. This work provides a new paradigm for the treatment of orthotopic glioma and other tumor types. [Display omitted] [ABSTRACT FROM AUTHOR]

The current study analyzed the piezoelectrically driven mechanism responsible for generating force in both rectangular and hummingbird wings, which mimicked the flapping motion of the micro air vehicles, utilizing a combination of numerical simulation and experimental approaches. Digital image correlation technology was employed within the experimental setup to capture the dynamic deformation pattern of the flapping wing, yielding dynamic deformation data. This dataset was subsequently integrated into the computational fluid dynamics (CFD) simulation software to explain the aeroelastic effects. In this way, the dynamic deformation data played a crucial role in computing inertial forces regarding wing flexibility. In addition, temporal force variations generated by the flapping wing were measured using a load cell. The numerical results provided a full understanding of the flapping wing's unsteady aerodynamics, with an emphasis on vortex formations and pressure distribution. We thoroughly examined the force produced by the piezo-actuated flapping wing system. This analysis was then rigorously compared with the data obtained from the load cell measurements. Our primary emphasis was on the vertical forces along the z-axis. Moreover, a thorough comparison of the combined CFD and experimental data inertial results revealed an overall agreement in the total forces from the load cell. [ABSTRACT FROM AUTHOR]

Piezoelectric materials have been proposed as embedded power source, which are capable of converting mechanical energy into electrical energy. However, power generated from a piezoelectric material usually comes with poor characteristics such as high voltage, low current and high impedance. In order to drive the embedded sensor circuit, piezoelectric power needs to be characterized and regulated. In this paper, we present an analysis on the power generation characteristics of the stiff lead zirconate titanate (PZT) ceramics and its equivalent circuit. It is then verified by simulation and experimental results. Since a single PZT element may not meet the needs of real-world embedded applications, we present experiments and analysis using four identical PZTs. Finally, we outline an application where PZT elements are used for power generation in a Total Knee Replacement (TKR) implant. [ABSTRACT FROM AUTHOR]

Hybrid organic-inorganic molecular ferroelectrics have emerged as promising materials for multifunctional piezoelectric devices. However, they present challenges in practical applications because of their inherent brittleness and poor ductility. Herein, we present a flexible mechano-optical dual-responsive molecular ferroelectric composite by incorporating trimethylchloromethyl ammonium (TMCM)-MnCl3 into styrene ethylene butylene styrene (SEBS) matrix. The SEBS/TMCM-MnCl3 exhibits excellent stretchable mechanical properties (tensile strain >1300%, thickness of 30 μm), piezoelectricity, and photoluminescence, enabling advanced visual-tactile- fused anticounterfeiting and encryption applications. Anticounterfeiting and antitampering tags are developed to judge whether the valued items are true or tampered with based on pattern recognition and piezoelectric response, respectively. Additionally, high-security password keyboards featuring triple-layer encryption are designed, offering more password combinations (524,288 times greater than those of traditional password devices relying solely on digital encryption) and enhanced security reliability against cracking attempts. This work can inspire designs of multifunctional optoelectronic materials and enable visual-tactile- fused intelligent applications in human-machine interfaces, information security, and advanced robotics. [ABSTRACT FROM AUTHOR]

Lead zirconate titanate (PZT) is a widely recognized piezoelectric ceramic exhibiting excellent dielectric and ferroelectric properties over a wide range of temperature and frequency, making it desirable for applications such as capacitors, piezoelectric transducers, and actuators. Being subjected to repeated electrical loading in various applications, a progressive decrease in the functionality can happen, leading to device failure over time. Therefore, understanding degradation phenomena in all aspects is of importance to expand the lifespan of electronic devices. Despite of many studies focusing on the macroscopic properties of ferroelectrics related to degradation, such as switchable polarization, little is known about the change on local ferroelectric and piezoelectric properties and the domain structure induced by degradation. This paper reports the effect of sub‐coercive electrical cycling on local static and dynamic piezoelectric properties for PZT ceramic using piezoresponse force microscopy (PFM). The piezoelectric properties are probed along the three sample directions (x, y, z) to gain comprehensive insights into the local domain orientation throughout the bulk PZT sample which is then compared with microscopically measured piezoelectric coefficients. The PFM results are analyzed with respect to changes in domain orientation (depolarization) as well as to reduction on piezoelectric material response (degradation) to identify the origin of the degradation behavior. Our results directly show a strong depolarization effect in the direction of the applied electric field because of sub‐coercive cycling although it leads to small or even no degradation in directions perpendicular to the applied electric field. However, the latter is associated with a notable change in dynamic polarization switching properties which are strongly tied to the local domain structure. Our study shows that the origin of the degradation can be identified by analyzing the statistical change of local piezoelectric properties. [ABSTRACT FROM AUTHOR]

This study proposes a sandwich structure 1-3 piezoelectric composite, incorporating flexible silicone rubber to enhance the thickness vibration mode of piezoelectric ceramics. Rigid aluminum nitride (AlN) is employed to bolster the mechanical stability of the composite. Utilizing equivalent parameter theory, we establish a mathematical model for the sandwich structure composite material. The impact of the piezoelectric phase size and the volume fraction of AlN on several performance parameters of the material are analyzed, including the thickness electromechanical coupling coefficient, density, sound velocity, and characteristic impedance. The sandwich structure piezoelectric composite was fabricated using the "cutting and filling" technique. Experimental outcomes reveal that this material demonstrates concentrated thickness vibration modes, with a thickness electromechanical coupling coefficient reaching as high as 0.72, a 16.6 % increase compared to traditional 1-3 piezoelectric composites. Results from thermal shock tests and tensile tests suggest that the sandwich structure 1-3 piezoelectric composite has considerable potential for use in highly reliable low-frequency receiving transducers. [ABSTRACT FROM AUTHOR]

RF energy harvesting converts ambient signals into electrical power, providing a sustainable energy source. This study demonstrates the use of a piezoelectric transformer for efficient RF energy harvesting. In this work, a piezoelectric transformer (PT) is employed as a high-gain, efficient inverting amplifier to enhance RF wireless energy harvesting. The PT, composed of lead zirconate titanate (PZT), is placed after the receiving loop antenna, with its output connected to an AC-to-DC converter circuit. Maximum harvested power was observed at the PT's resonance frequency of 50 kHz, with an optimal load of 40 kΩ. The system, comprising the antenna, transformer, and rectifier circuit, continues to resonate at 50 kHz, as confirmed by input impedance measurements, demonstrating stable and effective performance. The overall system efficiency was characterized to be 88%. [ABSTRACT FROM AUTHOR]

Cantilever beams with piezoelectric coating are the most widely used form of strain-driven energy harvesting. Almost all prior research on cantilever beam shapes aimed at enhancing energy output accounts for beams fully coated with piezoelectric materials. While a larger coating area, up to a certain limit, can enhance energy output, it also escalates the cost of the structure, as piezoelectric materials are very expensive. Output power density over the length of the beam/piezoelectric material varies significantly. Hence, a partially coated beam with an optimized positioning of piezoelectric material can not only cut the cost of the system but also warrant a higher output power density. On the other hand, optimizing the base beam shape always remains one of the top approaches to increasing the power output. As such, this work aims to select a cantilever beam design by investigating a wide variety of cantilever beam shapes while the beam is partially coated with the piezoelectric material to maximize the power output capacity of the harvester. In the first part of the study, an efficient size of the piezoelectric material and its placement in the host beam are selected based on the power capacity of the system. Next, the selected effective size and placement of the piezoelectric material is implemented in a wide range of cantilever beam shapes (e.g., trapezoidal, triangular, V-cut, concave, and convex) to select a host beam design for maximizing the output power density. To ascertain a comparable argument, the surface area, volume, and mass of all the considered beam shapes are kept consistent, as these parameters influence the power output of the harvester. The geometry of each shape is systematically varied to understand the effect of geometric configuration on the output power density. Additionally, an analysis is conducted to validate that the findings/selection of this study are independent of the thickness of the host beam or piezoelectric material. [ABSTRACT FROM AUTHOR]

This paper has reported a novel ternary system consisting of (1- x - y) BiScO 3 - x PbTiO 3 - y CaZrO 3 (y CZ-BS- x PT). The phase structure, microstructure and electrical parameters of the new piezoelectric material at room temperature were studied in detail. The results showed that d 33 increased significantly with the increase of CZ content. Combined with the results of phase structure, the MPB of 0.02CZ-BS- x PT is located at x = 0.615, which demonstrates optimum piezoelectric performance (d 33 = 470 pC/N， k p = 52.0 %, ε r = 1704). At the same time, the in-situ high-temperature electrical parameters were characterized systematically. It is worth noting that the in-situ electrical parameters are more attractive. When the temperature rises from room temperature to 300 °C, the k t and k p of 0.02CZ-BS-0.615 PT decreases by less than 7 % and the k p reaches the maximum of 60.7 % at 200 °C, and remains 49.8 % even at 300 °C. In addition, the in-situ d 33 test of 0.005CZ-BS-0.63 PT showed that the d 33 of the material increased from room temperature to 424 °C, reaching a maximum of 690 pC/N. From room temperature to 300 °C, the change rate is only 26 %, lower than that of the undoped BS-PT, which is 38.6 %. And the d 33 * reaches a maximum of 994 p.m./V at 200 °C. The improved in-situ piezoelectric properties of y CZ-BS- x PT ternary system makes it a great candidate for high temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

This study reports the characteristics of a piezoelectric nanogenerator (PENG) consisting of a mixture of polydimethylsiloxane (PDMS) and zinc tin oxide (ZTO) particles (ZTO@PDMS) with different shapes and phases. The output performance of PENGs with crystalline Zinc hydroxystannate(ZHS), amorphous ZTO, and crystalline ZTO of different phases was investigated based on annealing temperature. The fabricated PENGs with amorphous ZTO (a-ZTO) cubes showed a maximum output voltage of ∼4.3V and a current of ∼470 nA with a power of 3.14 μW, which is 249 % higher than that of the crystalline ZTO (c-ZTO) cube-based one. The amorphous ZTO (a-ZTO) nanosphere showed the highest output performance. The surface area of the piezoelectric material affected the residual polarization, which led to different piezoelectric properties. Therefore, we investigated the output performance of PENGs with various shapes while maintaining the same volumes of ZTO cubes and spheres. The molar ratio of the materials was varied during synthesis, revealing that the ZTO cubes have a higher output performance. The polarization-electric loops (P-E loops) showed a high remnant polarization (Pr∼25.89μC/cm2) in ZTO@PDMS films with larger 1103 nm cubes. These values were 170.5 %, 143.7 %, and 113.2 % larger than those observed in ZTO@PDMS films with cubes of size 826 nm, 978 nm, and 1047 nm, respectively. The ZTO nanocubes have a significant advantage in the fabrication of high output performance based on PENGs. [ABSTRACT FROM AUTHOR]

Sonopiezocatalytic therapy is an emerging therapeutic strategy that utilizes ultrasound irradiation to activate piezoelectric materials, inducing polarization and energy band bending to facilitate the generation of reactive oxygen species (ROS). However, the efficient generation of ROS is hindered by the long distance of charge migration from the bulk to the material surface. Herein, atomically thin Bi2O2(OH)(NO3) (AT‐BON) nanosheets are rationally engineered through disrupting the weaker hydrogen bonds within the [OH] and [NO3] layer in the bulk material. The ultrathin structure of AT‐BON piezocatalytic nanosheets shortens the migration distance of carriers, expands the specific surface area, and accelerates the charge transfer efficiency, showcasing a natural advantage in ROS generation. Importantly, the non‐centrosymmetric polar crystal structure grants the nanosheets the ability to separate electron‐hole pairs. Under ultrasonic mechanical stress, Bi2O2(OH)(NO3) nanosheets with the remarkable piezoelectric feature exhibit the desirable in vivo antineoplastic outcomes in both breast cancer model and liver cancer model. Especially, the AT‐BON‐induced ROS bursts lead to the activation of the Caspase‐1‐driven pyroptosis pathway. This study highlights the beneficial impact of bulk material thinning on enhancing ROS generation efficiency and anti‐cancer effects. [ABSTRACT FROM AUTHOR]

The concept of multisource energy harvesting has attracted attention in order to harvest multiple types of energy in a single material. In this work, Pb‐free (Ba,Ca)(Zr,Ti)O3 (BCZT) ceramics were used to investigate a combination of piezoelectric and pyroelectric energy harvesting behavior. The temperature dependence of the permittivity and the pyroelectric coefficient was measured, and the pyroelectric properties of BCZT were expected to improve near its orthorhombic–tetragonal phase transition temperature TO–T (∼40°C). The output voltage and current were measured using a BCZT plate, where the BCZT was oscillated under a temperature gradient to apply mechanical stress and temperature fluctuation simultaneously. The measured output voltage from the combined piezo‐ and pyroelectric contributions at a frequency of 2 Hz and with a load resistance of 10 MΩ was 1.4 times higher than the sole piezoelectric output voltage. The resulting combined output voltage was confirmed by finite element simulation. [ABSTRACT FROM AUTHOR]

Digital light processing (DLP) is a projection-based vat photopolymerization 3D printing technique that attracts increasing attention due to its high resolution and accuracy. The projection-based layer-by-layer deposition in DLP uses precise light control to cure photopolymer resin quickly, providing a smooth surface finish due to the uniform layer curing process. Additionally, the extensive material selection in DLP 3D printing, notably including existing photopolymerizable materials, presents a significant advantage compared with other 3D printing techniques with limited material choices. Studies in DLP can be categorized into two main domains: material-level and system-level innovation. Regarding material-level innovations, the development of photocurable resins with tailored rheological, photocuring, mechanical, and functional properties is crucial for expanding the application prospects of DLP technology. In this review, we comprehensively review the state-of-the-art advancements in DLP 3D printing, focusing on material innovations centered on functional materials, particularly various smart materials for 4D printing, in addition to piezoelectric ceramics and their composites with their applications in DLP. Additionally, we discuss the development of recyclable DLP resins to promote sustainable manufacturing practices. The state-of-the-art system-level innovations are also delineated, including recent progress in multi-materials DLP, grayscale DLP, AI-assisted DLP, and other related developments. We also highlight the current challenges and propose potential directions for future development. Exciting areas such as the creation of photocurable materials with stimuli-responsive functionality, ceramic DLP, recyclable DLP, and AI-enhanced DLP are still in their nascent stages. By exploring concepts like AI-assisted DLP recycling technology, the integration of these aspects can unlock significant opportunities for applications driven by DLP technology. Through this review, we aim to stimulate further interest and encourage active collaborations in advancing DLP resin materials and systems, fostering innovations in this dynamic field. [ABSTRACT FROM AUTHOR]

This paper investigates the nonlinear dynamic deflection, natural frequency, and wave propagation in functionally graded (FG) porous piezoelectric microscale tubes under periodic load, hygrothermal conditions, and an external electric field. The piezoelectric material used to make the smart microtubes has pores that may be smoothly changed or uniformly distributed over the tube wall. Here, three types of porosity distribution are taken into consideration. The nonlinear motion equations are constructed using a novel shear deformation beam theory and the modified couple stress theory (MCST). The nonlinear motion equations are solved using the fourth-order Runge–Kutta technique and the Galerkin approach. The effects of various geometric parameters, porosity distribution type, porosity factor, periodic load amplitude and frequency, material length scale parameter, moisture, and temperature on the nonlinear dynamic deflection, natural frequency, and wave frequency of FG porous piezoelectric microtubes are explored through a number of parametric investigations. [ABSTRACT FROM AUTHOR]

This paper investigates a quantitative comparison of the Love wave propagation due to traction-free and rigid boundary surfaces on the piezoelectric-dispersive layer over a non-dispersive initially stressed half-space. The model is considered (a) transversely isotropic piezoelectric material in the upper layer, (b) exponentially increasing dispersive (non-homogeneous) layer in the intermediate, and (c) initially stressed non-dispersive (homogeneous) medium in the lower half-space. Electrical potential fields in the piezoelectric layer are defined in terms of electrical potential function with open and short circuit piezoelectricity using the quasi-static Maxwell's equation. We have derived analytical dispersion relations for two cases of boundary conditions: (i) free surface with zero tractions and (ii) rigid boundary, in both the open and short circuit cases. The validities of the dispersion relations are shown by deriving some particular cases and compared with the classical dispersion relation of the Love wave. A novel numerical representation of changes in displacement amplitude with depth and comparative effect of various piezoelectric materials such as PZT-4, PZT-5A, PZT-7A, and BaTiO3 are shown using MATLAB software. The rigid boundary surface case is more effective than traction-free boundary surfaces in terms of electromechanical coupling factor. It is also identified that there are significant effects on the dispersion of the Love-type waves due to different boundary conditions on the upper surface of the model. These comparative studies highlight the present work and may be helpful in the fields of solid mechanics and material fabrication processes. [ABSTRACT FROM AUTHOR]

Extensive research has focused on green and renewable energies to address the increasing demand for flexible, reliable, and self-sustaining advanced technology and electrical supplies. Piezoelectric nanogenerators (PENGs) have garnered significant interest as a pioneering energy-harvesting technology, due to their notable advancements and capacity to effectively capture and convert mechanical energy from the environment into electrical power. This review article seeks to cover the latest developments and innovations in piezoelectric materials for PENG applications. It explores key topics, such as the strategic selection of piezoelectric materials to optimize energy-harvesting efficiency, advancements in fabrication techniques, and the evaluation of PENGs performance. Throughout this manuscript, critical points are highlighted that require further investigation in the field of high-performance piezoelectric material fabrication. Ongoing research is crucial for improving the flexibility and durability of functional materials, thus advancing the development of superior electronic devices with enhanced piezoelectric properties. Furthermore, addressing enhancements in the electromechanical properties of current piezoelectric materials is imperative. This review article aims to support researchers in their quest for a comprehensive understanding of piezoelectric mechanisms and offers valuable insights for the progression and refinement of PENGs, which have broad potential applications. An overview of the PENGs applications, piezoelectric materials selection, fabrication methods and PENGs performance discussed in this review paper. [ABSTRACT FROM AUTHOR]

Piezoelectric devices exhibit unique properties that vary with different vibration modes, closely influenced by their polarization direction. This paper presents an analysis on the free vibration of laminated piezoelectric beams with varying polarization directions, using a state-space-based differential quadrature method. First, based on the electro-elasticity theory, the state-space method is extended to anisotropic piezoelectric materials, establishing state-space equations for arbitrary polarized piezoelectric beams. A semi-analytical solution for the natural frequency is then obtained via the differential quadrature method. The study commences by examining the impact of a uniform polarization direction, and then proceeds to analyze six polarization schemes relevant to the current research and applications. Additionally, the effects of geometric dimensions and gradient index on the natural frequencies are explored. The numerical results demonstrate that varying the polarization direction can significantly influence the natural frequencies, offering distinct advantages for piezoelectric elements with different polarizations. This research provides both theoretical insights and numerical methods for the structural design of piezoelectric devices. [ABSTRACT FROM AUTHOR]

The mechanic-electro coupling overlapping finite element method (OFEM) is proposed to improve the accuracy in solving the mechanical characteristics of piezoelectric structures. Based on the basic equations and boundary conditions of piezoelectric materials, overlapping triangle elements are used to discretize the solution domain of piezoelectric structures, and the displacement function and potential function of the mechanic-electro coupling OFEM are constructed through local interpolation. The control equation of the mechanic-electro coupling OFEM is derived using the variation principle. The accuracy and validity of this method are verified by comparing with the reference solution and analytical solution in patch test and piezoelectric patch bending test. The static characteristics of the cantilever-typed piezoelectric sensor model, the rectangular plate with one-sided piezoelectric patch configuration, and the hole-containing piezoelectric energy harvester model are analyzed. The mechanic-electro coupling OFEM has high engineering value and broad application prospects in analyzing the structural mechanical properties of intelligent piezoelectric components. [ABSTRACT FROM AUTHOR]

This study develops a novel singularity analysis method that addresses the limitations posed by piezoelectric material quantity and the variation patterns of property functions in functionally graded piezoelectric materials (FGPMs). Given that piezoelectric composite materials consist of multiple materials, the material properties of FGPMs vary with respect to angle. By introducing the asymptotic assumption that governs the physical fields close to the notch vertex into the static equilibrium equations, a comprehensive set of characteristic equations is formulated. All singularity orders and corresponding characteristic angle functions of the notch are determined by numerically solving the established characteristic equations. The effects of the notch opening angle, piezoelectric material polarization direction, and boundary conditions on the electromechanical field singularity at the notch are assessed. The judicious selection of material variation patterns can alleviate notch singularity in FGPMs. Highlights: A novel method for studying the singularity of piezoelectric material notch is proposed.The singularity orders and the characteristic angle functions are obtained simultaneously.Multimaterial notch contained an arbitrary number of subdomains can be considered.The proposed method eliminates the need for solving complex transcendental equations. [ABSTRACT FROM AUTHOR]

Flexible piezoelectric materials have gained considerable attention due to their remarkable properties, including electromechanical coupling and high stretchability. These characteristics make them valuable in the realm of flexible electronic devices. However, the issue of fracture in these materials cannot be ignored. In general, these flexible/stretchable materials experience fractures when subjected to significant deformation, unlike brittle piezoelectric materials with low failure strain which have been extensively studied. There is a pressing need to investigate the fracture behavior of flexible piezoelectrics under finite deformation conditions. Within the framework of the phase field method, this work addresses the fracture of flexible piezoelectrics utilizing a nonlinear electromechanical material model. To investigate the influence of electrical boundary conditions on fracture behavior, a function related to the electric permittivity ratio and phase field variable is employed to degrade the electric energy density. By adjusting the electric permittivity ratio, the analysis encompasses the fracture behavior of flexible piezoelectric materials under the assumptions of electrically impermeable, semi-permeable, and permeable conditions, respectively. In order to solve the coupled governing equations, a residual controlled staggered algorithm (RCSA) is employed in the user element subroutine of commercial software ABAQUS. The simulation results indicate that fracture behavior in flexible piezoelectric materials is influenced by several factors, including material parameters, geometry, polarization direction, and the external electric field. Notably, when the poling direction is perpendicular to the electric field direction, variations in the external electric field have a minimal impact on fracture behavior. In contrast, when the poling direction is parallel to the electric field direction, the influence on fracture behavior is pronounced. These findings provide valuable insights for developing strategies to enhance the fracture resistance and durability of flexible piezoelectric materials in practical applications. [ABSTRACT FROM AUTHOR]

Geosynthetics are widely used in reinforced soil engineering because of their excellent performance. Currently, an increasing number of researchers are studying the fabrication of geosynthetics with both reinforcement functions and sensing abilities. Sensor-enabled piezoelectric geobelts (SPGBs) have great potential in the field of integrated soil reinforcement monitoring because of their ability to reinforce and sense soil. In this paper, polymer-based SPGBs that can be batch extruded were successfully prepared using high-density polyethylene (HDPE), polyolefin elastomer (POE), carbon black (CB), and piezoelectric ceramics (PZT), and the preparation rate of SPGBs was substantially improved. Laboratory tensile tests were conducted to test the strain–stress–impedance–voltage signals of SPGB in the tensile process at 45 different ratios. The results showed that the piezoelectric strain constant (d33) of SPGBs was up to 10.5 pC/N. The tensile strength and breaking strain of SPGBs reached their maximum values of 14 MPa and 26.37%, respectively, at 65% PZT content. During the tensile test, the SPGB normalized impedance increased with increasing strain, and there was a significant sudden increase at the time of damage. An empirical formula for strain-normalized impedance, which can be used to calculate the strain of SPGBs quantitatively, was established. The SPGB output voltage rapidly increased and then decreased with increasing strain, and two characteristic points can be used as warning signs to qualitatively describe the change of SPGBs. The results of this study can provide a design basis for the batch preparation of SPGBs in engineering. [ABSTRACT FROM AUTHOR]

The repair of bone defects from various causes remains a significant challenge in clinical settings. Piezoelectric materials have been demonstrated to promote osteogenic differentiation, among which barium titanate (BT) has been widely reported. Magnesium oxide (MgO) dopants not only enhance the piezoelectric properties but also stimulate the osteogenic and angiogenic properties in stem cells. In this study, a MgO‐modified BT/hydroxyapatite (MgO@BT/HA) piezoelectric ceramic scaffold was constructed using three‐dimensional (3D)‐printed technology. The results indicated that the addition of MgO improved the electrical properties of BT (d33 = 68.26 pC/N), and facilitated an increase in the proportion of HA (30%) while maintaining the piezoelectric coefficient (d33 = 2.04 pC/N) of the ceramic system. Furthermore, under the induction of low‐intensity pulsed ultrasound (LIPUS) stimulation, in vitro biosafety experiments confirmed that MgO@BT/HA exhibits excellent biosafety and promotes the osteogenic differentiation of dental pulp stem cells (DPSCs). [ABSTRACT FROM AUTHOR]

High‐temperature piezoelectric ceramics with excellent piezoelectric properties are key materials for high‐temperature piezoelectric devices. In this context, bismuth titanate–niobate (Bi3TiNbO9) is one of the most promising candidates, owing to its high Curie temperature (TC) > 900°C. However, the relatively low piezoelectric response of prototype Bi3TiNbO9 does not satisfy the requirements of high‐precision and high‐sensitivity applications. Herein, chromium‐substituted Bi3TiNbO9 with a nominal composition, Bi3Ti1−xCrxNbO9 (BTN‐100xCr), was prepared using the solid‐state reaction method. Raman spectroscopy and X‐ray diffraction refinements revealed structural distortions induced by the substitution of chromium. Piezo‐response force microscopy and ferroelectric hysteresis loops showed facile polarization reversal and domain wall movement in chromium‐substituted Bi3TiNbO9. The resultant structural distortion and domain wall movement served as intrinsic and extrinsic contributions to the enhancement of the piezoelectric properties, respectively. Consequently, BTN‐1.5Cr exhibits a high piezoelectric constant (d33) of 17.7 pC/N, which is four times that of Bi3TiNbO9 (4.2 pC/N), a high TC of 908°C, and an excellent thermal stability of piezoelectric and electromechanical coupling properties up to 500°C. These results indicate that chromium substitution enhances the high‐temperature piezoelectric properties of Bi3TiNbO9, and chromium‐substituted Bi3TiNbO9 is a promising candidate for high‐temperature piezoelectric applications. [ABSTRACT FROM AUTHOR]

• Flexoelectricity and surface effect on piezoelectric nanolaminates were reported. • Analytical solution of bending deformation and vibration were obtained. • Effects of residual surface stress and the flexoelectric coefficient were examined. • Effects of aspect ratio and plate thickness on bending behavior were examined. In this paper, a model of double-layer rectangular piezoelectric nanolaminates with different upper and lower surface properties is established. The bending and vibration behavior of the piezoelectric nanolaminates are evaluated and analyzed, taking into consideration the flexoelectric and surface effects. Utilizing the surface piezoelectric model, flexoelectric theory, and Kirchhoff plate theory, this study provides analytical solutions for the bending deflection and natural frequency of rectangular piezoelectric nanolamination materials under various boundary conditions. The results indicate that the effects of flexoelectric and surface influences on piezoelectric nanolaminates are associated with residual surface stress and flexoelectric coefficients. These effects can enhance the bending stiffness and decrease the natural frequency of the piezoelectric nanolaminates. Furthermore, altering the residual stress on the upper and lower surfaces of the laminates separately will result in different trends in bending deflection, while causing a consistent trend in natural frequency change. When the electric potential direction of piezoelectric nanolaminates is different, the bending deflection of piezoelectric nanolaminates will change accordingly. The natural frequency of piezoelectric nanolaminates is determined by the absolute value of the flexoelectric coefficients, and is independent of their positive or negative values. Both the surface effect and the flexoelectric effect are influenced by size-dependent behaviors. When the thickness of the laminates is sufficiently large, both the surface effect and flexoelectric effect can be disregarded. This paper's research methods and results provide theoretical models and analytical methods for the microstructure design, multi-physical field characterization, and bending deformation behavior of intelligent components containing rectangular piezoelectric nanolaminates. [ABSTRACT FROM AUTHOR]

[Display omitted] • The catalytic mechanism and material preparation based on the piezoelectric effect. • The application of the piezoelectric effect in wastewater purification is expounded. • The development of the piezoelectric effect-assisted water purification technology. • The challenges and prospects of the piezoelectric effect in wastewater purification. The demands of human life and industrial activities result in a significant influx of toxic contaminants into aquatic ecosystems. In particular, organic pollutants such as antibiotics and dye molecules, bacteria, and heavy metal ions are represented, posing a severe risk to the health and continued existence of living organisms. The method of removing pollutants from water bodies by utilizing the principle of the piezoelectric effect in combination with chemical catalytic processes is superior to other wastewater purification technologies because it can collect water energy, mechanical energy, etc. to achieve cleanliness and high removal efficiency. Herein, we briefly introduced the piezoelectric mechanisms and then reviewed the latest advances in the design and synthesis of piezoelectric materials, followed by a summary of applications based on the principle of piezoelectric effect to degrade pollutants in water for wastewater purification. Moreover, water purification technologies incorporating the piezoelectric effect, including piezoelectric effect-assisted membrane filtration, activation of persulfate, and battery electrocatalysis are elaborated. Finally, future challenges and research directions for the piezoelectric effect are proposed. [ABSTRACT FROM AUTHOR]

The conversion of ambient mechanical vibrations into electricity using piezoelectric nanogenerators (PENGs) has garnered significant attention from researchers over the past few years, in light of its potential in wearable applications. The high flexibility and significant ferroelectricity of poly(vinylidene fluoride) (PVDF) make them the most promising candidates for PENG applications among polymer piezoelectric materials. In the present work, NiO nanoparticles were incorporated in different ratios into a PVDF matrix, and their potential for use in piezoelectric nanogenerators was investigated. The PVDF/NiO (5 wt.%) nanocomposite PENG exhibited the highest electrical output, with a 2.8-fold increase in open-circuit voltage and short-circuit current observed as compared to a bare PVDF-based PENG. However, a further increase in the compositional ratio of NiO led to a decrease in PENG output. The improved piezoelectricity in the PVDF/NiO (5 wt.%) nanocomposite is attributed to the enhanced polar phases and improved ferroelectricity of PVDF. Further confirmation of the improved piezoresponse was explored by measurement of the piezoelectric coefficient (d33) and dielectric study of the nanocomposites. The PENG electrical output was further simulated using the finite elemental method in COMSOL Multiphysics 5.5. The simulated results matched well with the experimental output, which confirmed the improved electrical performance of the PVDF/NiO nanocomposite-based PENGs. The enhanced performance of the nanocomposite PVDF film is attributed to the higher β phase in the PVDF. The efficiency of the PENG devices in motion-sensing applications was also explored. Different output voltage signals corresponding to different movements of the nanocomposite-based PENGs make the device compatible with sensor applications. [ABSTRACT FROM AUTHOR]

(K,Na)NbO3(KNN)-based ceramics are a promising lead-free piezoelectric material that could replace Pb(Zr1−xTix)O3-based materials due to their higher Curie temperature and superior electrical properties. However, the volatilization of sodium and potassium during conventional high-temperature sintering makes it difficult to obtain KNN ceramics with a dense structure and excellent electrical properties. Herein, a conventional solid-phase method combined with microwave sintering is applied for the preparation of KNN ceramics. The influence of the microwave sintering process on the microstructure and electrical properties of KNN ceramics were studied. The optimal microwave sintering conditions for KNN ceramics were determined to be 1100°C for 50 min. Under these conditions, the ceramic samples exhibited excellent ferroelectric properties, with the maximum polarization (Pmax) of 20.4 μC/cm2 and a remanent polarization (Pr) of 18.1 μC/cm2. Additionally, the samples demonstrated impressive piezoelectric properties, including the maximum electric field-induced strain (Smax) of 0.0251%, a dynamic piezoelectric coefficient (d33*) of 125.5 pm/V, and a piezoelectric coefficient (d33) of 109.8 pC/N. The study has important implications for the use of microwave sintering to achieve the densification of the ceramic with volatile elements such as KNN-based ceramics at lower sintering temperature and short sintering time. [ABSTRACT FROM AUTHOR]

High frequency and large bandwidth are growing trends in communication radio-frequency devices. The LiNbO3 thin film material is expected to become the preferred piezoelectric material for high coupling resonators in the 5G frequency band due to its ultra-high piezoelectric coefficient and low loss characteristics. The main mode of laterally excited bulk acoustic wave resonators (XBAR) have an ultra-high sound velocity, which enables high-frequency applications. However, the interference of spurious modes is one of the main reasons hindering the widespread application of XBAR. In this paper, a Z-cut LiNbO3 thin film-based XBAR with arc-shaped electrodes is presented. We investigate the electric field distribution of the XBAR, while the irregular boundary of the arc-shaped electrodes affects the electric field between the existing interdigital transducers (IDTs). The mode shapes and impedance response of the XBAR with arc-shaped electrodes and the XBARs with traditional IDTs are compared in this work. The fabricated XBAR on a 350 nm Z-cut LiNbO3 thin film with arc-shaped electrodes operating at over 5 GHz achieves a high effective electromechanical coupling coefficient of 29.8% and the spurious modes are well suppressed. This work promotes an XBAR with an optimized electrode design to further achieve the desired performance. [ABSTRACT FROM AUTHOR]

Energy harvesting plays an important role in advancing personalized wearables by enabling continuous monitoring, enhancing wearable functionality and facilitating sustainable solutions. We aimed to develop a flexible piezoelectric energy harvesting system based on inorganic piezoelectric materials that convert mechanical energy into electricity to power a wide range of mobile and portable electronic devices. There is significant interest in flexible piezoelectric energy harvesting systems that use inorganic piezoelectric materials due to their exceptional physical features and prospective applications. Herein, we successfully demonstrated a flexible piezoelectric nanogenerator (PENG) designed by the co-doped rare-earth element ceramics (RE-PMN-PT) embedded in PVDF and PDMS composite film and attained a significant output performance while avoiding electrical poling process. The impact of dielectric characteristics on the electrical output of nanogenerators was investigated, together with the structure of the composites. The Sm/La-PMN-PT particles effectively amplify both the voltage and current output, showcasing their potential to power portable and wearable devices, as demonstrated by their capacity to illuminate LEDs. The maximal output power of 2 mW was correlated with the high voltage (220 V) and current (90 µA) of Sm/La-PMN-PT/PVDF, which demonstrated that the device has the potential for energy harvesting in biomedical applications. [ABSTRACT FROM AUTHOR]

Flexible sensors are in great demand in the field of wearable electronics because of their good softness, stretchability, breathability and structural elasticity. Besides, polyvinylidene fluoride (PVDF) and its copolymers have been considered as promising piezoelectric materials for advanced sensing and excellent biocompatibility. Electrospinning is simple, low cost, and scalable technology that can be used to fabricate PVDF-based nanofibers applied in long-term monitoring or human–computer interaction. In this paper, we initially presented the basic process for preparing PVDF nanofibers, followed by a systematic elaboration on extended electrospinning techniques to facilitate more in-depth research on PVDF-based nanofibers. Then, the enhancements methods were summarized, complemented by some reinforcing mechanisms, novel structures and some solutions for filler agglomeration. Furthermore, the latest applications as wearable sensors were introduced. Potential difficulties, problems and perspectives are also discussed. We hope that this article can help researchers better understand this field and push it to a higher level. [ABSTRACT FROM AUTHOR]

Recently, textured piezoelectric ceramics have become a hot topic in the field of piezoelectric materials. Due to their high cost-effectiveness, textured ceramics are expected to be the material of choice for the next generation of acoustic transducers. In this study, we investigated the coercive field (Ec), piezoelectric constant (d33), and dielectric constant (ε33) of textured PIN-PSN-PT ceramics under different torques, in response to the demand for the development of composite rod transducer technology for transmitting and receiving. Based on the obtained data, a wideband composite rod transducer was designed and fabricated using textured PIN-PSN-PT ceramics with high performance. Compared with conventional PZT piezoelectric ceramic transducers of the same size, the wideband composite rod transducer made with textured ceramics extends the frequency band to a lower frequency of 6.5 kHz, improves the emission performance by 2 dB, and enhances the reception performance by 2 dB. Compared with conventional PZT piezoelectric ceramics in the same frequency band, the acoustic performance is comparable, but there is a volume reduction of 59.23% and a weight reduction of 49.7%, solving the technical bottleneck of developing composite rod transducers that are miniaturized and lightweight. The research results of this study have important reference value for the engineering application of textured ceramic materials in acoustic transducers. [ABSTRACT FROM AUTHOR]

Piezoelectric ceramics with high electro strain are widely used in actuators, sensors, and so on. Here, this work investigates the electro strain of representative piezoelectric materials, and analyzes the influence of electrode type on the electro strain of PZT41 with significant strain anomalies. It is found that the occurrence of abnormally significant strain is not affected by the electrode but caused by intrinsic defects. Therefore, the ceramic samples with and without defects tailoring in Na 0.5 Bi 0.5 TiO 3 (NBT) based and PbZr 0.52 Ti 0.48 O 3 (PZT) based systems were prepared by the solid-state reaction method, and the results show that abnormally ultrahigh electro strains occur in excessively thin samples with diploes due to defects tailoring. Through displacement configuration experiments and comprehensive analysis of polarization switching processes, it is found that the occurrence of asymmetric abnormal significant strains is caused by reversible bending deformation in excessively thin samples. This work provides new support for the emergence of ultrahigh electro strain in piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Studies on the piezoelectric materials capable of efficiently outputting high electrostrains at low electric fields are driven by the demand for precise actuation in a wide range of applications. Large electrostrains of piezoceramics in operation require high driving fields, which limits their practical application due to undesirable nonlinearities and high energy consumption. Herein, a strategy is developed to enhance the electrostrains of piezoceramics while maintaining low hysteresis by incorporating lead magnesium niobate relaxors into lead zirconate titanium at the morphotropic phase boundary. An ultrahigh inverse piezoelectric coefficient d 33 * of 1380 pm/V with a reduced hysteresis of 11.5% is achieved under a low electric field of 1 kV/mm, outperforming the major lead-based piezoelectric materials. In situ synchrotron X-ray diffraction and domain wall dynamics characterization with sub-microsecond temporal resolution reveal that the outstanding performances originate from facilitated domain wall movement, which in turn is due to reduced lattice distortion and miniaturized domain structures. These findings not only address the pending challenges of effective actuation under reduced driving conditions but also lay the foundation for a more systematic approach to exploring the origin of large electrostrains. The authors develop an application-oriented low-field actuating piezoceramic via relaxor substitution. Their in situ synchrotron XRD analysis along with domain wall dynamics characterization reveals the mechanisms of outstanding performance. [ABSTRACT FROM AUTHOR]

Aqueous zinc-ion batteries (AZIBs) have become a promising and cost-effective alternative to lithium-ion batteries due to their low cost, high energy, and high safety. However, dendrite growth, hydrogen evolution reactions (HERs), and corrosion significantly restrict the performance and scalability of AZIBs. We propose the introduction of a BaTiO3 (BTO) piezoelectric polarized coating as an interface modification strategy for ZIBs. The low surface energy of the BTO (110) crystal plane ensures its thermodynamic preference during crystal growth in experimental processes and exhibits very low reactivity toward oxidation and corrosion. Calculations of interlayer coupling mechanisms reveal a stable junction between BTO (110) and Zn (002), ensuring system stability. Furthermore, the BTO (110) coating also effectively inhibits HERs. Diffusion kinetics studies of Zn ions demonstrate that BTO effectively suppresses the dendrite growth of Zn due to its piezoelectric effect, ensuring uniform zinc deposition. Our work proposes the introduction of a piezoelectric material coating into AZIBs for interface modification, which provides an important theoretical perspective for the mechanism of inhibiting dendrite growth and side reactions in AZIBs. [ABSTRACT FROM AUTHOR]

Bi0.5Na0.5TiO3 (BNT) emerges as a promising ferroelectric and piezoelectric lead-free candidate to substitute the contaminant Pb[TixZr1−x]O3 (PZT). However, to obtain optimal ferroelectric and piezoelectric properties, BNT must be sintered at high temperatures. In this work, the reduction of sintering temperature by using iron added to BNT is demonstrated, without significant detriment to the dielectric properties. BNT-xFe with iron from x = 0 to 0.1 mol (∆x = 0.025) were synthesized using high-energy ball milling followed by sintering at 900 °C. XRD analysis confirmed the presence of rhombohedral BNT together with a new phase of NaFeTiO4 (NFT), which was also corroborated using optical and electronic microscopy. The relative permittivity, in the range of 400 to 500 across all the frequencies, demonstrated the stabilization effect of the iron in BNT. Additionally, the presence of iron elevates the transition from ferroelectric to paraelectric structure, increasing it from 330 °C in the iron-free sample to 370 °C in the sample with the maximum iron concentration (0.1 mol). The dielectric losses maintain constant values lower than 0.1. In this case, low dielectric loss values are ideal for ferroelectric and piezoelectric materials, as they ensure minimal energy dissipation. Likewise, the electrical conductivity maintains a semiconductor behavior across a range of 50 Hz to 1 × 106 Hz, indicating the potential of these materials for applications at different frequencies. Additionally, the piezoelectric constant (d33) values decrease slightly when low concentrations of iron are added, maintaining values between 30 and 48 pC/N for BNT-0.025Fe and BNT-0.05Fe, respectively. [ABSTRACT FROM AUTHOR]

In this study, an Integrated Electronics Piezoelectric (IEPE)-type accelerometer based on an environmentally friendly lead-free piezoceramic was fabricated, and its field applicability was verified using a cooling pump owned by the Korea Atomic Energy Research Institute (KAERI). As an environmentally friendly piezoelectric material, 0.96(K,Na)NbO3-0.03(Bi,Na,K,Li)ZrO3-0.01BiScO3 (0.96KNN-0.03BNKLZ-0.01BS) piezoceramic with an optimized piezoelectric charge constant (d33) was introduced. It was manufactured in a ring shape using a solid-state reaction method for application to a compression mode accelerometer. The fabricated ceramic ring has a high piezoelectric constant d33 of ~373 pC/N and a Curie temperature TC of ~330 °C. It was found that the electrical and physical characteristics of the 0.96KNN-0.03BNKLZ-0.01BS piezoceramic were comparable to those of a Pb(Zr,Ti)O3 (PZT) ring ceramic. As a result of a vibration test of the IEPE accelerometer fabricated using the lead-free piezoelectric ceramic, the resonant frequency fr = 20.0 kHz and voltage sensitivity Sv = 101.1 mV/g were confirmed. The fabricated IEPE accelerometer sensor showed an excellent performance equivalent to or superior to that of a commercial IEPE accelerometer sensor based on PZT for general industrial use. A field test was carried out to verify the applicability of the fabricated sensor in an actual industrial environment. The test was conducted by simultaneously installing the developed sensor and a commercial PZT-based sensor in the ball bearing housing location of a centrifugal pump. The centrifugal pump was operated at 1180 RPM, and the generated vibration signals were collected and analyzed. The test results confirmed that the developed eco-friendly lead-free sensor has comparable vibration measurement capability to that of commercial PZT-based sensors. [ABSTRACT FROM AUTHOR]

Bone repair and regeneration require physiological cues, including mechanical, electrical, and biochemical activity. Many biomaterials have been investigated as bioactive scaffolds with excellent electrical properties. Amongst biomaterials, piezoelectric materials (PMs) are gaining attention in biomedicine, power harvesting, biomedical devices, and structural health monitoring. PMs have unique properties, such as the ability to affect physiological movements and deliver electrical stimuli to damaged bone or cells without an external power source. The crucial bone property is its piezoelectricity. Bones can generate electrical charges and potential in response to mechanical stimuli, as they influence bone growth and regeneration. Piezoelectric materials respond to human microenvironment stimuli and are an important factor in bone regeneration and repair. This manuscript is an overview of the fundamentals of the materials generating the piezoelectric effect and their influence on bone repair and regeneration. This paper focuses on the state of the art of piezoelectric materials, such as polymers, ceramics, and composites, and their application in bone tissue engineering. We present important information from the point of view of bone tissue engineering. We highlight promising upcoming approaches and new generations of piezoelectric materials. [ABSTRACT FROM AUTHOR]

A basic solution to the problem of three collinear equal cracks in a transversely isotropic piezoelectric material plate is obtained under the influence of electromechanical forces. Stroh formalism and complex variable methods are used to derive the mathematical expressions for SIF (stress intensity factor), COD (crack opening displacement), and COP (crack opening potential). The length of the saturation zones is investigated at each crack tip under the influence of quadratically varying electric displacement. Furthermore, a numerical study is carried out to discuss the effect of quadratically varying electrical potential on the saturation zone, COD, and COP. The results obtained numerically are reported graphically. [ABSTRACT FROM AUTHOR]

Broadband vibration attenuation is a challenging task in engineering since it is difficult to achieve low-frequency and broadband vibration control simultaneously. To solve this problem, this paper designs a piezoelectric meta-beam with unidirectional electric circuits, exhibiting promising broadband attenuation capabilities. An analytical model in a closed form for achieving the solution of unidirectional vibration transmission of the designed meta-beam is developed based on the state-space transfer function method. The method can analyze the forward and backward vibration transmission of the piezoelectric meta-beam in a unified manner, providing reliable dynamics solutions of the beam. The analytical results indicate that the meta-beam effectively reduces the unidirectional vibration across a broad low-frequency range, which is also verified by the solutions obtained from finite element analyses. The designed meta-beam and the proposed analytical method facilitate a comprehensive investigation into the distinctive unidirectional transmission behavior and superb broadband vibration attenuation performance. [ABSTRACT FROM AUTHOR]

At present, rigid-flexible coupling systems have been used in various engineering fields extensively, due to task demands, the systems have become complex increasingly, and thus, it is crucial to study the dynamic problems and active control of rigid-flexible coupling systems. Piezoelectric materials with electromechanical coupling phenomenon have great applications in active control of rigid-flexible coupling systems. In the current study, the active control of rigid-flexible coupling rectangular thin plate is investigated based on piezoelectric effect. The dynamic model of rigid-flexible coupling piezoelectric rectangular thin plate is established first using the Hamilton's principle, and its discrete form is obtained using the superposition method. The dynamic equations of the system are numerically solved using the Newmark-β method. The active control of the rigid-flexible coupling system has been carried out. Case studies show that, for rigid-flexible coupling rectangular thin plate, the rigid motion will drive the vibration of flexible thin plate, and the vibration of the flexible thin plate can cause rigid body motion. The piezoelectric patch can achieve active control of rigid body motion and flexible plate vibration simultaneously. The active control effect is related to the distribution position and thickness of the piezoelectric patch, as well as the excitation voltage. The closer the piezoelectric patch is to the edges of the rectangular thin plate, the better the active control effect on the rigid body motion. The closer the piezoelectric patch is to the center of the rectangular thin plate, the better the active control effect on the flexible plate vibration. Furthermore, the thicker the piezoelectric patch, the greater the excitation voltage, and the better the active control effect. The conclusion of the current work has direct and important engineering applications. [ABSTRACT FROM AUTHOR]

In this work, the sound transmission loss (STL) of a simply supported doubly curved shallow aluminum shell covered by two layers of piezoelectric material, PZT-5H is presented. The study takes into account the presence of uncertain ambient temperature which is shown to significantly affect piezoelectric control of sound transmission. To derive the equations of motion, the assumed mode method combined with the first-order shear deformation theory and Hamilton's principles are employed. The modeling process incorporates the ambient temperature and thoroughly investigates its effects on STL, vibrational displacement, and piezoelectric voltage in terms of thermal strain, piezoelectric constants, and the pyroelectric coefficient uncertainties. Results show that uncertainty in environmental temperature significantly affects STL uncertainty up to 10% and vibrational displacement of the shell to the 15 times of its lowest value. The piezoelectric voltage also fluctuates with the variation in the temperature in a maximum range of 0.12–5.2 Volt. Further, the piezoelectric sensing voltage which accounts for the piezoelectric sensor thickness is observed to be highly sensitive to the temperature uncertainty with a maximum range of 0.65–7.6 Volt, causing depolarization and hysteresis nonlinearity. Thus, environmental temperature variation is considered as one of the main uncertain aspects for robust sound transmission controller. The proposed study provides an insightful investigation for robust piezoelectric control of STL in the presence of thermal uncertainty. [ABSTRACT FROM AUTHOR]

Piezoelectric materials capable of generating an inherent electric field under strain, exhibit promising applications in in-situ piezocatalysis and enhanced photocatalytic activities. SrTiO 3 (STO) is a photocatalytic material, but it faces challenges such as low efficiency in photogenerated carrier separation and transfer, as well as limited reduction and oxidation reactions. To address these issues, this study utilized the piezoelectric properties of tetragonal BaTiO 3 (BTO) nanoparticles and the photocatalytic properties of STO to prepare BaTiO 3 /SrTiO 3 composite materials for piezoelectric assisted photocatalytic degradation of dyes. Disperse BTO nanoparticles with different mass ratios in STO spinning solution to produce a suspension, which is electrospun to form BTO-STO-1:x. The optimal degradation performance and catalytic activity of BTO-STO-1:x were determined through testing to identify the best composite material. It provides a robust foundation for underpinning the coupling mechanism between the enhancement of piezoelectricity and photocatalytic effect, offering an efficient pathway for advancing the field of piezoelectric assisted photocatalysis. [ABSTRACT FROM AUTHOR]