Search

Bismuth-based piezoelectric ceramics are presently of immense interest to researchers as they are believed to be Pb-free alternatives to well-known lead zirconate titanate-based piezoceramics. Herein, the author reports a lead-free ternary solid solution (1−2x)Na0.5Bi0.5TiO3-xBaTiO3-xBa0.7Ca0.3TiO3 (x = 0.01, 0.03, 0.05, 0.07, and 0.09: BNT-BT-BCT) synthesized through a standard solid state reaction route. All the samples crystallized to a complete perovskite structure studied through the powder x-ray diffraction analysis. Rietveld analysis of x-ray diffraction data revealed a structural transformation from monoclinic (Cc) to tetragonal phase (p4mm) with the co-existence of monoclinic (Cc) and tetragonal (p4mm) phases in the samples of x ≥ 0.03. The temperature-dependent dielectric analysis of (x = 0.03 and x = 0.05) systems suggests relaxor characteristics near ferroelectric–antiferroelectric phase transition temperature (Td). A changeover from relaxor to a near normal ferroelectric character was realized for x ≥ 0.07. Furthermore, the existence of polar nano-regions (PNRs) was studied through HR-TEM. Interestingly, a low electric field (±25 kV/cm) driven enhanced piezoelectric [(with 0.22% of strain; Smax/Emax = 850 pm/V for x = 0.03) and (with 0.17% strain and Smax/Emax of 714 pm/V for x = 0.07)] and an electrostrictive [with 0.20% of strain; Smax/Emax = 820 pm/V for x = 0.05] was achieved around Td. This can be attributed to the combined effects of phase boundary, ferroelectric–antiferroelectric transition, and the existence of PNRs. [ABSTRACT FROM AUTHOR]

Lightweight flexible piezoelectric polymers are demanded for various applications. However, the low instinctively piezoelectric coefficient (i.e. d33) and complex poling process greatly resist their applications. Herein, we show that introducing dynamic pressure during fabrication is capable for poling polyvinylidene difluoride/barium titanate (PVDF/BTO) composites with d33 of ~51.20 pC/N at low density of ~0.64 g/cm3. The melt-state dynamic pressure driven energy implantation induces structure evolutions of both PVDF and BTO are demonstrated as reasons for self-poling. Then, the porous material is employed as pressure sensor with a high output of ~20.0 V and sensitivity of ~132.87 mV/kPa. Besides, the energy harvesting experiment suggests power density of ~58.7 mW/m2 can be achieved for 10 N pressure with a long-term durability. In summary, we not only provide a high performance lightweight, flexible piezoelectric polymer composite towards sustainable self-powered sensing and energy harvesting, but also pave an avenue for electrical-free fabrication of piezoelectric polymers. Lightweight flexible piezoelectric polymers are demanded for various applications, but restricted by the low instinctively piezoelectric coefficient and complex poling process. Here, the authors develop a high performance lightweight, flexible self-poled piezoelectric polymer composite towards sustainable self-powered sensing and energy harvesting. [ABSTRACT FROM AUTHOR]

The modulus of elasticity of concrete ( E c ) is an essential parameter commonly used in concrete design, concrete curing monitoring, and deterioration evaluation and damage detection of concrete structures. A quick and reliable in situ determination of E c helps in accurate decision-making for construction and maintenance. The electromechanical impedance (EMI) technique using surface-bonded lead zirconate titanate (PZT) patches (referred to as SBP) has become a popular nondestructive method for monitoring concrete structures due to ease of operations. The existing research mainly utilized baseline-dependent approaches to monitor the changes (e.g., hardening or damage evolution) of concrete structures. However, relevant baselines are greatly influenced by the status of PZT sensors and bonding layers, limiting the practical applications of this technique. This paper presents a baseline-free EMI resonance method for measuring E c of concrete without using prior baseline data for the first time. Numerical and experimental studies on standard concrete cubes (100 mm in width) with SBP were conducted to examine the proposed method. A dimensionless physical quantity was first proposed to view the EMI signals. Then, resonance peaks highly related to concrete properties but insensitive to the status of the sensor system were selected, physically described, and correlated to the concrete parameters through numerical analyses. Finally, experimental validations, covering the measurement of E c , repeatability of the chosen resonance peaks, and temperature effects, were conducted to illustrate the proposed method's stability, accuracy, and sensitivity. [ABSTRACT FROM AUTHOR]

This study introduces a novel image capture and lighting techniques using a cutting-edge hybrid MEMS scanner system designed for compact microscopic imaging. The scanner comprises a tapered optical fiber waveguide and innovative aerosol-jet printed PZT (lead zirconate titanate) bimorph push-pull actuators on a stainless-steel substrate, effectively addressing issues that are commonly associated with PZT on silicon substrates such as fracture and layer separation. By leveraging nonlinear vibration, the scanner achieves a spiral scan pattern from a single signal input, in addition to the expected two-dimensional scanning and target illumination from two phase-shifted inputs. This capability is further enhanced by a novel process to taper the optical fiber, which reduces illumination scattering and tunes the fiber to the resonant frequencies of the scanner. The precisely tapered tip enables large fields of view while maintaining independent 2-axis scanning through one-degree-of-freedom actuation. Experimental validation showcases the successful generation of a spiral scan pattern with a 60 μm diameter scan area and a 10 Hz frame rate, effectively reconstructing scanned images of 5 μm lines, cross patterns (15 μm in length with a 5 μm gap), and structures of a Psychodidae wing. [ABSTRACT FROM AUTHOR]

Low strain limits the further application of Pb(Zr,Ti)O 3 (PZT) piezoelectric ceramics in actuators. Herein, a ternary piezoelectric ceramic x PbTiO 3 -(0.95- x)PbZrO 3 -0.05(Bi 0.5 Na 0.5)TiO 3 (x PT-PZ-BNT) is proposed and prepared by solid-state method to improve the strain characteristics. Results indicate that a biased electric field is intentionally constructed by defects arising from the incorporation of BNT into PZ-PT ceramic, which promotes non-180° domains to restore to initial states, thereby contributing to the increase in strain. Moreover, the electric domain configuration is efficiently modified by adjusting the component proportion in x PT-PZ-BNT ceramics, in which the 0.42 PT-PZ-BNT presents short and broad domains with fast response to external electric field. Rayleigh analysis indicates that the strain contributed by domain switching is dominant in PT-PZ-BNT ceramics under a high electric field. Consequently, a large strain of 0.4% is achieved in 0.42 PT-PZ-BNT ceramic with the variation less than 10% in the temperature range of 25∼175 °C. This study not only deeply analyzes the effect of domain configuration on the strain for PZT piezoelectric ceramics, but also demonstrates an effective approach to increase the strain through constructing internal biased electric field and regulating domain configuration. [ABSTRACT FROM AUTHOR]

Achieving synergy between high solid loading and low viscosity for ceramic suspensions a critical issue in the field of stereolithography. In this work, we successfully obtained a well-dispersed PZT suspension with high solid loading (55 vol%) and low viscosity (3047.5 mPa s at 60 rpm) by adding appropriate amounts of dispersant (1 wt% KOS110) and thickening agent (2 wt% PEG300), providing a foundation for crack-free photosensitive lead zirconate titanate (PZT) samples. This work presented a simple approach for achieving synergy between the high solid loading and low viscosity of ceramic suspensions for stereolithography-based additive manufacturing. [ABSTRACT FROM AUTHOR]

This article presents a study on Electromagnetic radiation (EMR) energy harvesting characteristics of lead zirconate titanate (PZT) of soft grade (SP 5 A) samples under drop weight impact load. In the present study, four samples having different diameter to thickness (d/t) ratio were used. A possible EMR energy harvesting mechanism from these samples under impact loading has been discussed. It is found that the EMR parameters viz. EMR voltage, generated EMR energy, and so on, depend on the dimension of the sample and applied mechanical energy. The sample having highest t/d2 (0.069) produces maximum EMR voltage, that is, 2.31 V. Also for the same sample, EMR parameters increase with the increase in applied mechanical energy. Also an increasing pattern of EMR energy was observed with the increase in the capacitance value of the capacitor. The results obtained suggest the possibility of using PZT as a better option for energy harvesting, sensing, and structural health monitoring applications. Also the results suggest EMR technique as an alternative option for harnessing energy from piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

Effective damage identification is paramount to evaluating safety conditions and preventing catastrophic failures of concrete structures. Although various methods have been introduced in the literature, developing robust and reliable structural health monitoring (SHM) procedures remains an open research challenge. This study proposes a new approach utilizing a 1-D convolution neural network to identify the formation of cracks from the raw electromechanical impedance (EMI) signature of externally bonded piezoelectric lead zirconate titanate (PZT) transducers. Externally bonded PZT transducers were used to determine the EMI signature of fiber-reinforced concrete specimens subjected to monotonous and repeatable compression loading. A leave-one-specimen-out cross-validation scenario was adopted for the proposed SHM approach for a stricter and more realistic validation procedure. The experimental study and the obtained results clearly demonstrate the capacity of the introduced approach to provide autonomous and reliable damage identification in a PZT-enabled SHM system, with a mean accuracy of 95.24% and a standard deviation of 5.64%. [ABSTRACT FROM AUTHOR]

This letter quantifies the phases by Rietveld refinement of perovskite relaxor ferroelectric ceramics of lanthanum-modified lead titanate zirconate (PLZT 9/65/35) as a function of temperature. The refinement results show the relative limit of phases between the polar electrical percolation and their vanishing as a function of temperature, coincident with dielectric measurements. The quantification of polar/nonpolar phases simultaneously is structural description of the polar clusters in relaxor ferroelectrics ceramics. The temperature changes in the polar/nonpolar phase ratio suggest a volume dynamism of the polar clusters as a function of temperature. [ABSTRACT FROM AUTHOR]

In this paper, detailed studies of effect of small amount of manganese substitution (at the zirconium site) on the structural, micro-structural, and electrical characteristics of lead zirconate titanate of Pb(Zr0.35–xMnxTi0.65)O3;x = 0, 0.02, 0.06, 0.10 (PZMT)) have been reported. The materials were prepared by using standard ceramic technology. The formation of the compounds and their basic crystal data have been studied through X-ray diffraction (XRD) method. The crystallite size and lattice strain of the compounds, evaluated from Scherrer's and Hall Williamson (H-W) equations, is found to be in the range of 40–50 nm and 11 × 10−4 to 50 × 10−4, respectively. Microstructures of different magnifications, revealing the surface nature of the compounds, have been recorded by field emission scanning electron microscope (FESEM). Effect of Mn+4 ions on electrical behavior (electrical impedance (Z*), electrical modulus (M*), conduction and relaxation phenomenon) of PZMT systems, over wide range of temperature and frequency, has been studied. [ABSTRACT FROM AUTHOR]

Civil engineering is not just about construction of buildings, towers, bridges etc. but also of their caring and maintenances. For this purpose all the constructed structures have to be monitored for their structural health in terms of damage detection, severity of damage etc., collectively called structural health monitoring (SHM) of structures in civil engineering. For SHM, electromagnetic impedance (EMI) technique is one of the best methods of NDTs being used in the field of civil engineering. EMI uses lead zirconate titnate (PZT) as its piezoelectric component for the purpose of measurement. PZT based devices are widely used in civil engineering. There is a huge demand for health monitoring now a days and to full fill those demands of health monitoring, PZT is one among the most reliable and cost efficient material. Piezoelectric sensor can be used to measure changes in acceleration, strain, pressure and to ensure the better safety measures. These PZT based sensors can be used for predicting the natural disasters like earthquake that helps to save the thousands of lives and can decrease property lose. The piezoelectric sensors can be used to monitor the civil structure which helps an engineer to analyses the characteristics of that structure. It is also used for collecting the data of force that is being exerted on the ground by the building, temperatures and pressure differences in environment etc. Damage detection is a technique that is used to monitor the civil structure, this can improve safety and ensure durability, and for concrete structures, damage detection plays an important role. For the purpose of SHM and damage detection PZT based sensors can be used. For civil engineering applications, PZT-cement based composites have been developed. The concrete and host structure such PZT-cement based composites shows better matching when compared to normal or other piezoelectric ceramics. In this review work we have discussed about SHM/Damage detection, Vibrational control, PZT embedded cement composites and PZT embedded in concrete. [ABSTRACT FROM AUTHOR]

Having the distinction of being one of the most extensively employed piezoelectric ceramic materials worldwide and multi-faceted, lead zirconate titanate (PZT) has numerous applications and characteristics. In 1954, a remarkable discovery happened at the Tokyo Institute of Technology, which was the development of PZT. Due to its excellent dielectric constant, piezoelectric value, polarization, high Curie temperature, and flexibility, it has been widely used in the field of mechanical engineering, along with other branches of sciences. The main interest of this review article is to describe the significance and involvement of PZT in the field of mechanical engineering. This article starts with a brief review of the history of PZT, after that different synthesis methods, and applications of PZT in relevance to the field of mechanical engineering have been discussed. Finally, this article concludes with the future scope of PZT in the field of mechanical engineering. [ABSTRACT FROM AUTHOR]

Fragility and the presence of a poisonous substance (lead) are the two major issues with traditional piezoceramics and structures that include them. This work suggests an active structure that is lightweight, flexible, and eco-friendly such that a polymeric foam plate is sandwiched between two piezoelectrically activated nanocomposite layers. A combination of a polymer and piezoelectric nanowires (NWs) of zinc oxide (ZnO) is used in the nanocomposite layers. For the proposed active structure, two types of void distributions and functionally graded (FG) distributions of the NWs have been assumed in each corresponding layer. The buckling characterization of the proposed eco-friendly active sandwich plate (EFASP) under biaxial mechanical loads has been conducted using an extended meshless solution based on a third-order theory. An in-depth parametric study on the EFASPs' biaxial buckling resistance revealed that increasing NW content considerably enhances buckling resistance, with this enhancement strongly reliant on the distribution profile of the NWs. Moreover, it was observed that embedding voids in the substrate layer can lead to a large structural weight reduction while only marginally lowering the buckling performance of suggested EFASPs. [ABSTRACT FROM AUTHOR]

Pyroelectric materials, are those materials with the property that in the absence of any externally applied electric field, develop a built-in spontaneous polarization in their unit cell structure. They are regarded as ideal detector elements for infrared applications because they can provide fast response time and uniform sensitivity at room temperature over all wavelengths. Crystals of the perovskite Lead Titanate (PbTi O 3 ) family show pyroelectric characteristics and undergo structural phase transitions. They have a high Curie temperature (the temperature at which the material changes from the ferroelectric (polar) to the paraelectric (nonpolar) phase), high pyroelectric coefficient, high spontaneous polarization, low dielectric constant, and constitute important component materials not only useful for infrared detection, but also with vast applications in electronic, optic, and Micro-electromechanical systems (MEMS) devices. However, the preparation of large perfect, and pure single crystals of PbTi O 3 is challenging. Additionally, difficulties arise in the application of such bulk crystals in terms of connection to processing circuits, large size, and high voltages required for their operation. A number of thin film fabrication techniques have been proposed to overcome these inadequacies, among which, magnetron sputtering has demonstrated many potentials. By addressing these aspects, the review article aims to contribute to the understanding of the challenges in the field of pyroelectric materials, highlight potential solutions, and showcase the advancements and potentials of pyroelectric perovskite series including PbZrTiO3 (PZT), P b x C a 1 − x (PZN-PT), etc. for which PbTi O 3 is the end member. The review is presented in two parts. Part 1 focuses on material aspects, including preparation methods using magnetron sputtering and material characterization. We take a tutorial approach to discuss the progress made in epitaxial growth of lead titanate-based ceramics prepared by magnetron sputtering and examine how processing conditions may affect the crystalline quality of the growing film by linking to the properties of the substrate/buffer layer, growth substrate temperature, and the oxygen partial pressure in the gas mixture. Careful control and optimization of these parameters are crucial for achieving high-quality thin films with desired structural and morphological characteristics. [ABSTRACT FROM AUTHOR]

A mesoscopic model for a polymer-based magnetoelectric (ME) composite film is developed. The film is assumed to consist of a piezoelectric polymer matrix of the PVDF type filled with CFO-like single-domain nanoparticles. The model is treated numerically and enables one to obtain in detail the intrinsic distributions of mechanical stress, polarization and electric potential and helps to understand the influence of the main configurational parameters, viz., the poling direction and the orientational order of the particle magnetic anisotropy axes on the electric response of the film. As the model is fairly simple—it uses the RVE-like (Representative Volume Element) approach with a single-particle cell—the results obtained are rather of qualitative than quantitative nature. However, the general conclusions seem to be independent of the particularities of the model. Namely, the presented results establish that the customary ME effect in composite films always comprises at least two contributions of different origins, viz., the magnetostrictive and the magnetoactive (magnetorotational) ones. The relative proportion between those contributions is quite movable depending on the striction coefficient of the particles and the stiffness of the polymer matrix. This points out the necessity to explicitly take into account the magnetoactive contribution when modeling the ME response of composite films and when interpreting the measurements on those objects. [ABSTRACT FROM AUTHOR]

Ultrasonic flowmeter is one of the most widely used devices in flow measurement. Traditional bulk piezoelectric ceramic transducers restrict their application to small pipe diameters. In this paper, we propose an ultrasonic gas flowmeter based on a PZT piezoelectric micromachined ultrasonic transducer (PMUT) array. Two PMUT arrays with a resonant frequency of 125 kHz are used as the sensitive elements of the ultrasonic gas flowmeter to realize alternate transmission and reception of ultrasonic signals. The sensor contains 5 × 5 circular elements with a size of 3.7 × 3.7 mm2. An FPGA with a resolution of ns is used to process the received signal, and a flow system with overlapping acoustic paths and flow paths is designed. Compared with traditional measurement methods, the sensitivity is greatly improved. The flow system achieves high-precision measurement of gas flow in a 20 mm pipe diameter. The flow measurement range is 0.5–7 m/s and the relative error of correction is within 4%. [ABSTRACT FROM AUTHOR]

In addition to traditional piezoelectric polymers, mono-crystals and ceramics, piezoelectrets or charged voided polymers have shown an interesting piezoelectric response by converting the mechanical energy into electrical and vice versa, therefore being incorporated in a number of advanced electromechanical transducers. This article is a review on the different phases for the elaboration of pseudo piezoelectric films based on passive polymers. First, several methods for the elaboration of the cellular structure of these materials are explained in the main text, with the morphological representation of the reached porosity. The porosity represents a cell to embed the positive and negative electrical charges created by the most common electrical charging processes, which are subsequently mentioned. Different theoretical models are emphasized as well to predict the piezoelectric behavior of this porous polymers. Finally, some of the latest harvesting energy applications based on porous polymers are collected. All the considerations cited above make Piezoelectric porous polymers open access materials that can be developed and optimized by the control of the porosity then used in energy harvesting applications. [ABSTRACT FROM AUTHOR]

Wearable piezoelectric micropumps may contribute to improving drug delivery in the field of medicine. Poly(vinylidene fluoride/trifluoroethylene) (P(VDF/TrFE)), an organic ferroelectric polymer, is a desirable material for fabricating the piezoelectric layer of medical micropumps owing to its biocompatibility and flexibility. However, a large voltage is required to drive the micropumps because the piezoelectric response of P(VDF/TrFE) is small compared with that of inorganic materials, such as lead zirconate titanate. In this study, thin films (P(VDF/TrFE)) are focused that can reduce applied voltage and improve the flexibility of entire actuators. In addition, actuators sealed with poly(monochloro‐paraxylene) (Parylene C) are considered, which has excellent chemical resistance, flexibility, and biocompatibility. The calculated piezoelectric constant |e31| of the fabricated P(VDF/TrFE) thin films is 42 mC m−2. A large deformation of 1 mm is observed in the fabricated cantilever‐type actuators sealed with Parylene C when a voltage of 160 V is applied. Furthermore, the vibration of the actuators by the reverse piezoelectric effect on the water surface is observed. It is indicated in these results that a low voltage can safely drive P(VDF/TrFE) thin‐film piezoelectric actuators sealed with Parylene C in medical micropumps. [ABSTRACT FROM AUTHOR]

In self-polarized lead zirconate titanate thin films formed on platinized silicon substrates, a significant increase in the internal electric field was observed as a result of long-term aging. To explain this phenomenon, a mechanism is proposed for the formation of the internal field associated with the diffusion of charged oxygen vacancies, which, in turn, is due to the action of a mechanical stress gradient. The diffusion coefficient of charged oxygen vacancies was estimated to be ~ 3 × 10–16 cm2/s. [ABSTRACT FROM AUTHOR]

The scientific community has raised increasing apprehensions over the transparency and interpretability of machine learning models employed in various domains, particularly in the field of materials science. The intrinsic intricacy of these models frequently results in their characterization as "black boxes", which poses a difficulty in emphasizing the significance of producing lucid and readily understandable model outputs. In addition, the assessment of model performance requires careful deliberation of several essential factors. The objective of this study is to utilize a deep learning framework called TabNet to predict lead zirconate titanate (PZT) ceramics' dielectric constant property by employing their components and processes. By recognizing the crucial importance of predicting PZT properties, this research seeks to enhance the comprehension of the results generated by the model and gain insights into the association between the model and predictor variables using various input parameters. To achieve this, we undertake a thorough analysis with Shapley additive explanations (SHAP). In order to enhance the reliability of the prediction model, a variety of cross-validation procedures are utilized. The study demonstrates that the TabNet model significantly outperforms traditional machine learning models in predicting ceramic characteristics of PZT components, achieving a mean squared error (MSE) of 0.047 and a mean absolute error (MAE) of 0.042. Key contributing factors, such as d33, tangent loss, and chemical formula, are identified using SHAP plots, highlighting their importance in predictive analysis. Interestingly, process time is less effective in predicting the dielectric constant. This research holds considerable potential for advancing materials discovery and predictive systems in PZT ceramics, offering deep insights into the roles of various parameters. [ABSTRACT FROM AUTHOR]

Piezoelectric motors designed for operation in the ITER tokamak-reactor must be tested for stability under severe radiation conditions. Properties of lead zirconate-titanate that is the most common type of piezoelectric materials were analyzed from the point of view on influence of radiation. It is shown that, at the expected in ITER level of radiation, this piezoceramics has a good potential for resistance to radiation induced amorphization and depolarization. [ABSTRACT FROM AUTHOR]

Semiconducting effects in zinc oxide nanowires‐based nanogenerators greatly impact their performances. A coupled model integrating piezoelectric and semiconducting properties is developed with a finite element method to better understand the phenomena involved in this kind of device made with a process including chemical bath deposition of the nanostructures and their polymer encapsulation. Free carriers and surface traps are taken into account to give some keys to explain differences between previous theoretical and experimental works. This model is first validated on a single nanowire with a 1016 cm−3 n‐doping level by comparison with analytical calculations. For this comparison, surface traps are not taken into account as no analytical solution is available considering them. Second, n‐doping levels (between 1012 and 1018 cm−3) and surface traps densities (between 108 and 1012 cm−2) lead to variations of the generated piezopotential of two orders of magnitude. The control of these two semiconducting properties is a real challenge for this kind of application. Furthermore, simulation results show that the benefic effect of 1–3 piezo‐composite is still present even for a high n‐doping level of 1018 cm−3. [ABSTRACT FROM AUTHOR]

With the advancement in smart electronic devices and self‐powered devices, the demand for piezoelectric polymers has found potential research interest. Among these, electrospun polyvinylidene fluoride (PVDF) fibers have gained attention for energy harvesting due to their flexibility and higher piezoelectric coefficient. In the current work, various methods are compared to enhance PVDF's piezoelectric properties, including different solvents (DMAc, DMF), conductive filler (rGO), and annealing as post‐treatment. The results indicate that PVDF/rGO fibers in DMAc solvent exhibit the highest β phase fraction and crystallinity. Moreover, for the first time, the piezoelectric properties of PVDF/rGO electrospun single fiber is presented using high voltage switching spectroscopy piezoelectric force microscopy (HVSS‐PFM). The highest piezoelectric coefficient (d33) is measured for PVDF/DMAc‐rGO composite fibers. Notably, PVDF/rGO in DMAc solvent significantly improves the piezoelectric coefficient, leading to a remarkable fourfold increase in power density compared to pure PVDF, making it a promising material for energy harvesting applications. [ABSTRACT FROM AUTHOR]

A handful of piezoelectrics cover all of today's technologies, so there is a need to expand the range of accessible piezoelectric properties to enable future fundamental and technological advances. Focusing on Space Group 186, we have computed the piezoelectric properties of 47 materials, and deployed machine-learning models to reveal the quantities that control them. We have found reasonable linear models for the case of wurtzites, from a dataset of only 19 entries. Some of these models are based on easily retrievable features, while others involve features requiring additional computations. In the case of non-wurtzite materials, the statistical learning has not found any meaningful correlations, since the diversity of structures and compositions in a set of 26 non-wurtzite entries obliterates the influence of features on piezoelectric coefficients. The linear models presented for the wurtzite coefficients can potentially be used to inform future searches for wurtzite-structured alloys with higher piezoelectric coefficients. [ABSTRACT FROM AUTHOR]

Barium tantalum oxynitride (BaTaO2N), as a member of an emerging class of perovskite oxynitrides, is regarded as a promising inorganic material for solar water splitting because of its small band gap, visible light absorption, and suitable band edge potentials for overall water splitting in the absence of an external bias. However, BaTaO2N still exhibits poor water‐splitting performance that is susceptible to its synthetic history, surface states, recombination process, and instability. This review provides a comprehensive summary of previous progress, current advances, existing challenges, and future perspectives of BaTaO2N for solar water splitting. A particular emphasis is given to highlighting the principles of photoelectrochemical (PEC) water splitting, classic and emerging photocatalysts for oxygen evolution reactions, and the crystal and electronic structures, dielectric, ferroelectric, and piezoelectric properties, synthesis routes, and thin‐film fabrication of BaTaO2N. Various strategies to achieve enhanced water‐splitting performance of BaTaO2N, such as reducing the surface and bulk defect density, engineering the crystal facets, tailoring the particle morphology, size, and porosity, cation doping, creating the solid solutions, forming the heterostructures and heterojunctions, designing the photoelectrochemical cells, and loading suitable cocatalysts are discussed. Also, the avenues for further investigation and the prospects of using BaTaO2N in solar water splitting are presented. [ABSTRACT FROM AUTHOR]

Polymer-based composites filled with ceramic particles such as barium titanate (BT) or lead zirconate titanate (Pb (Zr,Ti)O3) are considered as ideal materials for energy storage capacitors in electric systems. In this study, we fabricated poly (methylmethacrylate) (PMMA)/poly (vinylidene fluoride) (PVDF) composite films filled with a small amount (10 wt%) of BT by solution casting and investigated their dielectric properties. Our results indicate that the dielectric constants and breakdown strengths of the composites are strongly influenced by the mass content of PMMA. Furthermore, the composite film exhibits excellent energy properties (Ue, ~ 9.145 J cm−3; η, ~ 73.84%) when the mass ratio of PVDF and PMMA is 5:5. These composites possess significant potential as high-performance dielectric materials for energy storage capacitors. [ABSTRACT FROM AUTHOR]

Piezoelectric nanogenerators (PENGs) have attracted great interest owing to their broad range application in environmental mechanical energy harvesting to power small electronic devices. In this study, novel flexible and high-performance double-layer sandwich-type PENGs based on one-dimensional (1-D) and two-dimensional (2-D) zinc oxide (ZnO) nanostructures and Ni foam as the middle layer have been developed. The morphology and structure of 1- and 2-D ZnO nanostructures have been studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). To investigate the effect of structural design on the piezoelectric performance, single-layer PENGs were also fabricated. The piezoelectric output of all prepared PENGs were evaluated under different human impacts at various forces and frequencies. The double-layer designed PENGs showed a two times larger voltage output compared to the single-layer PENGs, and the use of Ni foam as middle-layer and of 2-D ZnO nanosheets (compared to 1-D nanorods) was also found to increase the performance of the designed PENGs. The working mechanism of the prepared PENGs is also discussed. The design of nanogenerators as double-layer sandwich structures instead of two integrated single-layer devices reduces the overall preparation time and processing steps and enhances their output performance, thus opening the gate for widening their practical applications. [ABSTRACT FROM AUTHOR]

Piezoelectric nanogenerators (PENGs) are the core components of self-powered devices used in sensors, ecofriendly wearable gadgets, and biomedical implants. This study introduces and demonstrates a flexible PENG with supersonically cold-sprayed films of cobalt titanate (CTO) and polyvinylidene fluoride (PVDF). An electrically poled PENG produces a maximum output voltage of 34.8 V under a tapping force of 20 N, whereas a CTO/PVDF-based PENG exhibits 25.4 V across a loading resistance ( R L ) of 50 MΩ and generates a short-circuit current of 30 μA at 0.1 MΩ. Furthermore, the maximum power density is 25 μW·cm-2 at R L = 0.6 MΩ. Cyclic tapping and bending test results show that open-circuit voltages (Voc) of 25.4 and 5.8 V are produced under the tapping cycle of N tap = 4200 and bending cycle of N bend = 750 , respectively, confirming the mechanical durability of the PENG. Thus, the potential of CTO/PVDF films for use in PENGs with various functionalities can be confirmed based on the V oc values generated from bending, mobile tapping, walking, and lifting movements. [ABSTRACT FROM AUTHOR]

The paper shows how different sintering methods affect the basic characteristics of PZT-type multicomponent ceramics. A perovskite-structured multicomponent ceramic of lead zirconate titanate (PZT) type doped with Mn4+, Sb3+, W6+, and Ni2+ and with a chemical composition of Pb(Zr 0.49 Ti 0.51) 0.94 Mn 0.015 Sb 0.01 W 0.015 Ni 0.03 O 3 was obtained. Ceramic powders were synthesized using the calcination method. Three sintering methods, including: (i) pressureless free sintering (FS), (ii) hot pressing (HP), and (iii) spark-plasma sintering (SPS), were used for the final sintering. The electrophysical measurements of the PZT-type ceramics, including scanning electron microscopy microstructure (SEM), X-ray diffraction (XRD), dielectric, ferroelectric, piezoelectric properties, and DC electrical conductivity, are presented. The microstructure of the samples is characterized by densely packed grains with correctly crystallized grain shapes but with different average grain sizes for each sintering technology used. At room temperature (RT), PZT ceramic samples have high values of resistivity ρ DC (from 7.25 × 108 Ωm to 1.14 × 109 Ωm), high values of permittivity (from 1048 to 1307), and low values of dielectric loss factor (from 0.008 to 0.02). Samples with the most favorable dielectric, ferroelectric, and electromechanical parameters were obtained using the FS and HP sintering methods. In the case of spark-plasma sintering (SPS), the assumed improvement in the electrophysical properties of the P-SPS ceramic sample was not obtained. Also, the most advantageous piezoelectric parameters have ceramic samples obtained by the FS and HP methods. The conducted tests verify that all the obtained ceramic compositions have a complete set of parameters suitable for micromechatronic applications. [ABSTRACT FROM AUTHOR]

Smart ferroelectric lead zirconate titanate (PbZr0.52Ti0.48O3) was synthesized in the morphotropic phase boundary by a sol-gel autocombustion strategy. The as-prepared powder was calcined at three different temperatures, 700, 800, and 900 °C for 3 h, each. The tetragonality of the final product increases with the rise of calcination temperature. Thermal gravimetric analysis and differential thermal gravimetric analysis depicted that complete crystallization of PZT was observed at 400 °C. Structural, vibrational, and microstructure studies were investigated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy investigated for grains and elemental analyses and high-resolution transmission electron microscopy (HR-TEM). Results of XRD and HR-TEM were compatible, showing the formation of nanocrystalline powder with coexisting tetragonal and rhombohedral phases. Rietveld refinement of XRD data was carried out using material analysis using diffraction software in order to obtain the lattice constants. For mechanical and electrical measurements, disks were pressed at 10MPa. The samples were burned out at 500 °C for 1 h and then 1100 °C for 2 h to obtain more dense disks. The surfaces of the disks were coated with silver paste, followed by burning out for almost an hour. Dielectric and piezoelectric characteristics for the fabricated PZT samples were determined in detail. From these analytical techniques and collected data, one can deduce that the sample annealed at 900 °C can be used as an ultrasonic transducer in various metrological applications. [ABSTRACT FROM AUTHOR]

High‐power piezoelectric ceramics are typically driven to output vibration velocity (v0) under high AC electric fields. Herein, the Fe2O3 doped 0.125 Pb(Zn1/3Nb2/3) O3–0.075 Pb(Mn1/3Nb2/3)O3–0.8 Pb(Zr0.48Ti0.52)O3(PZMNZT–xFe; x = 0.05–0.35) piezoelectric ceramics were prepared to enhance v0, and the favorable comprehensive electrical properties, such as d33 = 315 pC/N, Qm = 1738, kp = 0.58, kt = 0.48, εr = 1156, tan δ = 0.4%, and Tc = 320°C, were achieved in the PZMNZT–0.15Fe ceramic. Most importantly, the PZMNZT–0.15Fe ceramic presented a reliable v0 of 0.90 m/s, which was 2.25 times of the commercial PZT4 ceramic (∼0.40 m/s). The excellent high‐power performance should be attributed to ordering functional elements such as crystal grains and ferroelectric domains. Overall, this work reveals that the PZMNZT–0.15Fe ceramic is competitive for high‐power applications. [ABSTRACT FROM AUTHOR]

Quasicrystals have aroused great interest and argument among researchers due to their unique atomic configurations. In this paper, based on the Stroh formalism and Barnett-Lothe matrices, we investigate the problems of two-dimensional piezoelectric quasicrystal composite wedges and spaces subjected to different loadings, such as line force and line dislocation. The special cases of the semi-infinite spaces, infinite spaces, and bi-material composite spaces are also taken into consideration. We derive the analytical expressions of displacements and stresses by considering the continuities of the displacements and surface tractions on the radial plane. After that, the comparative study regarding the infinite space problem, between solutions from Green's function and solutions from our method, is performed to verify the accuracy of the formulation and numerical results. Numerical examples are given to present the mechanical behaviors of quasicrystal under different loadings. The results prove that line force affects phonon displacement more clearly than phason displacement, but line dislocation affects stresses and electric displacement little. [ABSTRACT FROM AUTHOR]

PLZT (lanthanum-doped lead zirconate titanate) ceramic with outstanding photostrictive effect has been widely used in the micro precision drive field. In this article, a new closed-loop control method with ON-OFF control strategy is proposed for the photoelectric actuator based on PLZT ceramic. The closed-loop control model under driving voltage control strategy is established, and the parameters are identified by a series of experiments. Then, the control equations of driving voltage and output displacement of the photoelectric actuator are derived on the basis of the closed-loop control model during the light on and light off phases. After that, the numerical simulation analysis is carried out when the driving voltage and output displacement are taken as control objects respectively. According to the analysis results, the output displacement of the photoelectric actuator can be successfully controlled at a specific target value, and the proposed control method has excellent control effect, the feasibility and effectiveness of the control method are verified. Relevant conclusions can lay a foundation and provide theoretical guidance for the practical application of the photoelectric actuator in the field of active control. [ABSTRACT FROM AUTHOR]

The effect of the intrinsic properties of silicone rubber and barium titanate (BaTiO3) nanoparticles on the piezoelectric properties of BaTiO3/silicon rubber composites was studied by the finite element analysis. The data of the simulation show that the stress and voltage of the composite were greatly increased when the concentration of the BaTiO3 nanoparticle increased from 5 to 30 vol. %. As Young’s modulus of silicone rubber increased from 5 to 20 MPa, the compressive stress of the composites raised linearly. With the Poisson’s ratio rising from 0.41 to 0.49, the compressive stress increased by 0.18 MPa in the process. When the dielectric constant of the BaTiO3/silicon rubber composite was less than 30, the potential difference of the piezoelectric film gradually raised with the dielectric constant increasing. When the dielectric constant of the composite was higher than 30, the output voltage of the composite gradually decreased. Therefore, the lower Young’s modulus and Poisson’s ratio of the silicone rubber composite is beneficial to improve the piezoelectric properties of the composite. This article will provide a reference for designing the preparation of spherical BaTiO3 composite materials. [ABSTRACT FROM AUTHOR]

Health monitoring plays an important role in the maintenance of asphalt pavement. Tubular smart aggregate (TSA) is a cylindrical sensor composed of lead zirconate titanate (PZT) and protective coating. Ultrasonic waves are produced when the TSA vibrates and can be used to monitor the health of asphalt pavement. The influence of the protective coating material of the TSA, elastic modulus of PZT, and diameter of the TSA on the TSA resonant frequency was studied. A voltage signal and mechanical load were applied to the TSA; vibration and the received voltage of the TSA were collected. Furthermore, two TSAs were embedded in an asphalt mixture to transmit and receive ultrasonic waves. The vibration and generated voltage by the TSA embedded in the asphalt mixture were collected. Results indicate that the resonant frequency of the TSA increases with the increase of the elastic modulus of protective coating and PZT. With the increase of the diameter of the TSA, the resonant frequency of the TSA decreases gradually. When the voltage signal and mechanical load subjected to the TSA were close to the resonant frequency of the TSA, larger vibration and voltage were generated. Due to the viscoelasticity of the asphalt mixture, the resonant frequency of the TSA embedded in an asphalt mixture was reduced. [ABSTRACT FROM AUTHOR]

A composition-dependent structural, microstructure, ferroelectric, and energy storage performance of novel barium-based (1 − x)Ba(Zr0.1Ti0.9)O3 − x(Ba0.85Ca0.15)TiO3[(1 − x)BZT − xBCT] pseudo-binary systems with x = 0.0, 0.3, 0.5, 0.7 and 1 are investigated systematically. The barium zirconate titanate, BZT (x = 0.0), and barium calcium titanate, BCT (x = 1) ceramics exhibited a single-phase rhombohedral (R) and tetragonal (T) perovskite structure, respectively. The derivative of [(1 − x)BZT − xBCT] compositions with x = 0.3 enters into the orthorhombic phase (O), and the other two compositions with x = 0.5 and 0.7 compositions enter into the tetragonal phase. The surface morphologies reveal dense, uniform grain size varies from 2.59–12.05 μm with the addition of BCT to the BZT matrix. The presence of all the elements is confirmed using EDX analysis, and the existence of both Ti4+ and Ti3+ valence states in the Ti core level found in the sample. The maximum polarization is 15.06 μC/cm2 achieved for the x = 0.3 sample at 15.50 kV/cm applied field. The recoverable energy density (Wrec) and energy efficiency (η) are estimated to be nearly 167 mJ/cm3 and 42%, respectively. These outstanding characteristics of [(1 − x)BZT − xBCT] ceramics are ascribed to polymorphic phase boundaries, demonstrating their superior ferroelectric and optical properties. The present study may pave a new path in designing dielectric ceramics through intermixing MPBs for energy storage and multifunctional electro-optical devices. [ABSTRACT FROM AUTHOR]

This study explores the effects of filler concentrations of lanthanum-doped lead zirconate titanate (PLZT) on the electrical and mechanical characteristics of nanocomposite thick film. Crystal structure and morphology of the thick film have been studied using X-ray diffraction, atomic force microscopy, and scanning electron microscopy techniques. It has been noted that adding PLZT nanoparticles to the polyvinylidene fluoride (PVDF) matrix modifies the physical properties of PVDF. In the nanocomposite film, the most prominent polar β phase has been identified at 6 mol% of PLZT filler. In all the films, a nearly homogenous grain distribution has been observed. Frequency-dependent dielectric, conductivity, and impedance of the sample were studied at room temperature. Maximum electric dipole polarization of 0.68 μC/cm2 and piezoelectric (d33) constant of 48 pC/N have been observed at 6 mol% of PLZT filler in the PVDF matrix. Indeed, it has been observed that the (0.94)PVDF–(0.06)PLZT nanocomposite film is well suited for applications such as nanogenerators, structural health monitoring systems, and various kinds of sensors and actuators. [ABSTRACT FROM AUTHOR]

Flexible wearable sensing devices are in great demand for self-powered systems. In this study, we fabricated fiber films of poly(vinylidene fluoride) (PVDF) matrix embedded with modified lead zirconate titanate nanoparticles (PZT NPs) using the electrospinning process. Each fiber film was cut into small pieces of 2 × 2 cm2, and pairs of pieces were pressed with a hot-pressing method. Modified PZT NPs with a high piezoelectric coefficient were embedded in PVDF fibers as a piezoelectric-reinforcing phase, which promoted the formation of the polar β phase in PVDF. The embedded PZT NPs affected the distribution of the polarized electric field and formed a local electric field between two PZT NPs, which promoted the polarization of PVDF, thereby enhancing the piezoelectric properties of PVDF/PZT NPs fiber films. The piezoelectric coefficient (d33) of the PVDF/PZT NPs fiber films embedding 4 wt.% PZT NPs showed the most significant enhancement, from 12 pC/N for neat PVDF to 21 pC/N, which is an approximately 75% improvement. The results of this work demonstrate the great potential application of piezoelectric composite fiber films in flexible wearable sensing devices. [ABSTRACT FROM AUTHOR]

In this work, we report a systematic study of complex La3+ and Sc3+ doped lead zirconate titanate ceramics with the stoichiometric formula (PbZr0.53Ti0.47)0.90 (LaxSc1−x)0.10O3−δ for x = 0.2, 0.4, 0.6, and 0.8 denoted as PLZTS2, PLZTS4, PLZTS6, and PLZTS8, respectively (abbreviated as PLZTS10x), synthesized using the solid-state reaction method. We carried out dielectric measurements on Ag/PLZTS10x/Ag metal–ferroelectric–metal capacitors as a function of temperature (100–650 K) and frequency (102–106 Hz). Upon increasing La3+ concentration, the dielectric constant was found to be increased up to x = 0.6 and attained the highest value of ∼1800 at room temperature, and consequently, the highest saturation polarization was observed. The relaxor behavior of PLZTS8 can be attributed to the polar nano regions created in the materials. A recoverable energy density of ∼1162 mJ/cm3 with an excellent efficiency of ∼79% was achieved under an applied electric field of 97 kV/cm. The demonstrated high dielectric constant (ɛ′), spontaneous polarization (Ps), and energy density make these bulk materials promising for ferroelectric memory and energy-storage applications. [ABSTRACT FROM AUTHOR]

Several high-explosive (HE) crystals are known to be piezoelectric. However, no systematic study has been carried out on how this effect can be utilized. In this paper, we report the results of an analysis on the response of composites consisting of HE crystals and a polymeric binder under electrostatic excitation. The HE crystals considered are 1,3,5-trinitroperhydro-1,3,5-triazine, octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine, pentaerythritol tetranitrate, and ammonium perchlorate. To explore avenues for enhancing the piezoelectric effect, the binder of the composites is taken to be piezoelectric polyvinylidene fluoride. The focus is on the distributions of induced electric field vector and mechanical stress in the microstructures. The effects of crystal–binder volume fraction, HE crystal size, and dielectric constants of the HE crystals are investigated. To further explore the effect, microparticles of lead zirconate titanate piezoelectric ceramic are introduced to some microstructures. For the HE crystals considered here, a coupled electromechanical analysis shows that the microstructural heterogeneities can enhance the local electric fields to as high as 1.34 times the applied E-field, causing the dielectric breakdown field strength of the overall composite to be much lower than the breakdown strengths of the constituents in the microstructure. In addition, the induced stress levels just prior to dielectric breakdown are well below the yield strengths of the respective constituents. As such, controlled dielectric breakdown, rather than mechanical damage, should primarily be used to facilitate hotspot formation, ignition, and chemical reaction. The likelihood of local dielectric breakdown within the HE crystals is systematically quantified as a function of applied electric field, microstructural attributes, and constituent behavior. To gauge the effect of the direct piezoelectric effect, one material case is also subjected to mechanical excitation in the form of compression. Under an applied external stress, the results show that the direct piezoelectric effect can lead to local yielding and thereby serve as a hotspot generation mechanism. On the other hand, the induced E-field is weak and unlikely to serve as a practical or efficient means of effecting hotspots within an energetic material. The analysis points out that simultaneous application of electrostatic excitation and mechanical excitation can also be considered. [ABSTRACT FROM AUTHOR]

10.1063/5.0044758 82 M. Makarovic, M. Ç. Bayir, H. Ursic, A. Bradesko, and T. Rojac, "Domain wall conductivity as the origin of enhanced domain wall dynamics in polycrystalline BiFeO3", J. Appl. Phys. 10.1063/5.0029582 79 D. Zhang, D. Sando, Y. Pan, P. Sharma, and J. Seidel, "Robust ferroelectric polarization retention in harsh environments through engineered domain wall pinning", J. Appl. Phys. Today, it is established that ferroic domain walls represent outstanding functional nano-entities with unique physical properties, which are exploited in the rapidly expanding field of domain-wall nanoelectronics.[[16], [23]] Due to their low local symmetry and the distinct structural, electric, or magnetic environment, ferroic domain walls can behave substantially differently than the surrounding domains. Ferroic materials exhibit long-range order with respect to their elastic, electric, or magnetic properties, giving rise to fascinating physics and functional properties that are used in, e.g., state-of-the-art sensor technology, energy harvesting, and medical diagnosis. [Extracted from the article]

We present a novel electric permittivity sensor based on Bleustein–Gulyaev (BG) waves. Toward that end, we formulate the nonlinear electromechanical partial differential equations governing a BG wave resonator. We find that the permittivity of the material-under-test changes the sensor natural frequencies, thereby enabling the implementation of a frequency-shift permittivity sensor. We also find that the sensor sensitivity is enhanced by increasing bias voltage to drive the sensor into the nonlinear regime. Bias was found to be limited by electrical breakdown. The sensor was fabricated by depositing aluminum electrodes on a shear-poled lead zirconate titanate piezoelectric substrate. Experimental measurements of the displacement on the sensor surface were in good agreement with the developed model. [ABSTRACT FROM AUTHOR]

The in-plane dielectric and ferroelectric properties of preferentially oriented lead zirconate titanate (PZT) thin films are characterized using interdigitated transducers (IDTs). By combining finite element method simulations and capacitance measurements, values of the dielectric constant of films with thicknesses between 150 nm and 800 nm are obtained. A modified Sawyer–Tower circuit is used to investigate the polarization loops measured in-plane using IDT electrodes. A well-defined hysteresis loop is obtained demonstrating the switching of the polarization of the ferroelectric domains. Leakage current measurements reveal high resistivity and are an indication of the high quality of the PZT film. The obtained characteristics are used to determine the total impedance of the IDT-PZT structure. Here, the structure is represented by an equivalent ladder circuit using the inductance and resistance of the IDT electrodes and the capacitance and conductance of the PZT film. The obtained total impedance matches low frequency measurements. [ABSTRACT FROM AUTHOR]

The polarization and strain response of ferroelectric materials at electric fields below the macroscopic coercive field is of paramount importance for the operation of many electronic devices. The response of real ferroelectric and related materials is, in general, complex and difficult to interpret. The reason for this is that many processes in a ferroelectric material contribute to its properties, often concurrently. Examples include the motion of ferroelectric and ferroelastic domains, the presence of domains within domains, the dynamics of different types of polar nano-entities, the interaction of polar nano-entities (e.g., polar nanoregions in relaxors) with the strain and polarization within domains, motion of defects, and rearrangement of defect clusters and their interaction with polarization and strain. One signature of these processes is nonlinearity of the strain and polarization. Most ferroelectrics exhibit nonlinear response at all practical field levels, meaning that the apparent material coefficients depend on the amplitude of the driving excitation. In this paper, we show that an investigation of nonlinear behavior is a sensitive way to study various mechanisms operating in dielectric and piezoelectric materials. We review the basic formalism of the nonlinear description of polarization and strain, give a physical interpretation of different terms, and illustrate this approach on numerous examples of relaxors, relaxor ferroelectrics, hard and soft ferroelectrics, and morphotropic phase boundary compositions. An experimental approach based on a lock-in technique that is well suited for such studies is also discussed. [ABSTRACT FROM AUTHOR]

The structural and electroactive properties of the as-prepared random copolymer polyvinylidene-co-hexafluoropropylene thin film are explored as a function of thermal treatment at various temperature regions. The thermal treatment of the polymer thin film not only changes the structural conformations that is very natural but establishes a polar domain in the non-polar α-phase. Here, we discover an anomalous temperature-dependent crossover behavior from the non-polar α-phase to an appreciable enhancement in ferroelectric and piezoelectric responses. The maximum unipolar strain (S m a x = − 5.01 %) , an ultrahigh value of normalized piezoelectric coefficient (d 33 ∗ = − 556 pm / V) , high electromechanical coupling factor (K p = 0.78) factor including the high dielectric constant (ϵ ′ = 23 at 100 Hz) at a relatively low electric field of 900 kV/cm may, therefore, be an effect of the established polar domain for the sample annealed at 105 °C. The direct piezoelectric charge coefficient (d33), a key factor for the performance of a prepared polymer thin film system as an energy harvester, lies in the range of − 10 ± 2 pC / N. Also, the annealed sample exhibited a persistent polarization after several cumulative cycles of applied stress. [ABSTRACT FROM AUTHOR]

The ferroelectric, ferroelastic, and dielectric properties as well as the crystal structure were investigated for polycrystalline donor doped lead zirconate titanate (PZT) with grain sizes ranging from 0.25 to 5 μm, which were prepared using a novel zirconium titanium hydrate precursor (ZTH) with a specific surface area of 310 m2/g. Piezoforce microscopy was used to investigate the change in the domain structure, revealing a change in the domain configuration from a complex 3D structure to a simple lamellar domain formation at a 1 μm grain size that corresponded to a rapidly increasing internal mechanical stress observed with in situ synchrotron x-ray experiments. The correlation between the change in domain configuration, increasing internal stresses, effects of poling on the crystal structure, and the macroscopic ferroelectric and ferroelastic properties are discussed in detail, allowing a deeper understanding of size effects in polycrystalline donor doped PZT ceramics. [ABSTRACT FROM AUTHOR]

The motion of domain walls in lead zirconate titanate (PZT) produces both nonlinearity and hysteresis. While measurements of the resulting self-heating under an electric field drive are well known in bulk ferroelectric ceramics, self-heating effects in PZT films may differ from those in bulk ceramics due to a combination of reduced domain wall motion, differences in heat dissipation associated with substrates or passive elastic layers, and differences in typical drive fields. Here, it is shown that the thermal imaging of the test structures of PZT piezoelectric microelectromechanical systems using techniques such as infrared thermography and thermoreflectance thermal imaging suffers from motion-induced artifacts. These limitations were overcome via nanoparticle-assisted Raman thermometry with a spatial resolution of ∼1 μm. To acquire the local temperature distribution quantitatively, anatase nanoparticles were distributed across the electrodes and actuating PZT diaphragm. The temperature rise of the test structures increased as the operating frequency, voltage amplitude, and slew rate increased. As expected, the largest temperature rises were induced due to self-heating associated with domain switching under bipolar operation. In addition, a higher voltage amplitude testing revealed non-uniform temperature distributions across the piezoelectric actuator, suggesting that AC Joule heating can induce significant heat generation (ΔT ∼ 30 K) under high electric fields (∼390 kV/cm). [ABSTRACT FROM AUTHOR]

Piezoelectric diphenylalanine peptide nanotubes (PNTs) have recently been demonstrated in energy harvesting applications, typically based on vertically aligned PNTs that generate charge when pressed. In this work, we use a wettability difference and an applied electric field to align PNTs and PNT-based composites on flexible substrates. Open-circuit voltages and short-circuit currents exceeding 6 V and 60 nA, respectively, are achieved by bending the substrate, opening up the use of horizontally aligned PNTs as flexible energy harvesting substrates. [ABSTRACT FROM AUTHOR]