Piezoelectric Crystal Research Articles

Bending Analysis of Functionally Graded One-Dimensional Hexagonal Piezoelectric Quasicrystal Multilayered Simply Supported Nanoplates Based on Nonlocal Strain Gradient Theory

In this study, the nonlocal strain gradient theory is adopted to investigate the static bending deformation of a functionally graded (FG) multilayered nanoplate made of one-dimensional hexagonal piezoelectric quasicrystal (PQC) materials subjected to mechanical and electrical surface loadings. The FG materials are assumed to be exponential distribution along the thickness direction. Exact closed-form solutions of an FG PQC nanoplate including nonlocality and strain gradient micro-size dependency are derived by utilizing the pseudo-Stroh formalism. The propagator matrix method is further used to solve the multilayered case by assuming that the layer interfaces are perfectly contacted. Numerical examples for two FG sandwich nanoplates made of piezoelectric crystals and PQC are provided to show the influences of nonlocal parameter, strain gradient parameter, exponential factor, length-to-width ratio, loading form, and stacking sequence on the static deformation of two FG sandwich nanoplates, which play an important role in designing new smart composite structures in engineering.

Transmission properties of electromagnetic waves in piezoelectric photonic crystal with periodically reversed ferroelectric domains

We design the piezoelectric photonic crystal (PPC) with periodically reversed ferroelectric domains on the base of the structure of the piezoelectric superlattice, and study theoretically the transmission properties of electromagnetic (EM) waves in the PPC through Transfer Matrix Method of the photonic crystal (PhC). We analyze the mechanism for the influence of the piezoelectric effect on the transmission properties of EM waves in the PPC. The piezoelectric effect can influence the transmission properties of EM waves by changing the dielectric properties of the PPC. And we discuss the difference between the PPC and PhC. In the low frequency region, the reflection spectrum of PPC appear the total reflection and zero refractive indexes, and which doesn't exist in the PhC. In the high frequency region, the frequency positions and widths of the photonic band gaps of the PPC are higher and wider than cases of the PhC, respectively. Some potential applications are also discussed.

Piezoelectric Responses of Mechanically Exfoliated Two-Dimensional SnS2 Nanosheets.

The emergence of piezoelectric properties in two-dimensional (2D) layered transition metal dichalcogenides (TMDs) has triggered the intensive research on using low dimensional materials for conversion of mechanical stimuli into electrical signals or vice versa. While the bulk intrinsically presents no piezoelectric property, the origin of the piezoelectric responses in their 2D thin planes is ascribed to the loss of centrosymmetry. There are also other categories of 2D layered materials such as post-transition metal dichalcogenides (PTMDs) that might be of interests, which have been confirmed theoretically and are yet to be fully explored experimentally. In this work, we investigate the thickness-dependent piezoelectric responses of 2D tin disulfide (SnS2) nanosheets as a representative of layered PTMDs. The results indicate that the 2D SnS2 nanosheets with a thickness of ∼4 nm present an effective out-of-plane piezoelectric response of 2 ± 0.22 pm/V. Furthermore, the thickness dependence of the piezoelectric behavior at a resonant frequency shows that the piezoelectric coefficient decreases with increasing the thickness of 2D SnS2 nanosheets. Additionally, in reference to periodically poled lithium niobate piezoelectric crystal, the measured effective lateral piezoelectric coefficients at different voltages range from 0.61 to 1.55 pm/V with the average value at ∼1 pm/V. This study expands candidates for new piezoelectric materials in the 2D domain with comparable vertical and lateral coefficients, potentially opening a broader horizon for integration into sensors, actuators, and micro- and nanoelectromechanical systems.

Vibration Based Piezoelectric Energy Harvesting - A Review

In this digital race, electronic equipment has been integrated into human beings as a part of their body. Some electronic equipment is connected by wires, while some are self-powered by batteries. Today the ultra-low-power smart electronic gadgets and smart wireless sensor devices need an unlimited battery for enhancing the performance. In a remote area such as forests and hill areas, conventional charging methods of batteries by wire is not possible. Supplying power through wires is difficult. To overcome this, a sustainable solution is energy harvesting. The renewable sources for energy harvesting are light, heat, wind, tidal, motion, and vibration. Researchers have more interest in harvesting energy through mechanical vibration due to its abundant availability. This paper reviews the work about piezoelectric crystals and their role in energy harvesting, simulation software used, energy harvesting circuits and storage devices.

A magneto-mechano-electric (MME) energy harvester based on rectangular cymbal structure

In this work, we report a magneto-mechano-electric (MME) energy harvester with a rectangular cymbal structure consisting of a piezoelectric ceramic plate and magnetostrictive alloy (Metglass) foils. The magnetic field induced voltage was then predicted by using finite element analysis. Experimental results show that under a magnetic field excitation of 8 Oe at 180 Hz (resonance frequency), the MME energy harvester can generate a peak-peak output power of 5.7 mW and peak-peak current of 2.3 mA, respectively, for a load resistance of 5.6 kΩ, which allow to drive 10 LEDs lighting directly and stably. Correspondingly, its power density is 5.1 mW cm−3 at Hac =7 Oe, which is comparable with previous reports about traditional cantilever structure MME energy harvester using a piezoelectric single crystal. This work confirms that the MME energy harvester is a promising candidate for powering wireless sensors and other micro-energy smart electronics using the stray magnetic field, or even mechanical vibration energy in environment.

Unconventional piezoelectric coefficients in perovskite piezoelectric ceramics

Piezoelectric ceramics exhibit three conventional piezoelectric coefficients, i.e., d33, d31, d15, due to their ∞mm crystal symmetry. Unconventional piezoelectric coefficients, such as d11, d12, d13, d14, d16, etc., can only be extracted from piezoelectric single crystals of special symmetry with specific cut direction. Here we demonstrate a rotated poling method to realize unconventional piezoelectric coefficients in perovskite piezoelectric ceramics. This method is elaborated in theory and experimentally proven to be effective. Full nonzero piezoelectric coefficients in the 3 × 6 piezoelectric coefficients matrix can be obtained by combining these “quasi (effective) piezoelectric coefficients” with the conventional piezoelectric coefficients, which would expand applications in a wide variety of piezoelectric devices.

Control of Thermophysical Properties of Langasite-Type La3Ta0.5Ga5.5O14 Crystals for Pressure Sensors

We present a possible method to reduce the anisotropy of the thermal stress generated on langasite-type La3Ta0.5Ga5.5O14 (LTG) piezoelectric crystals arising from the mismatch of the thermal expansion coefficients and Young’s moduli of the crystals and metals at high temperatures. To formulate this method, the thermal stresses of order-type langasite crystals, in which each cation site is occupied by one element only, were calculated and compared to each other. Our results suggest that the largest cation site affects the thermal stress. We attempted to replace La3+ in LTG by a larger ion and considered Sr2+. Single crystals of strontium-substituted LTG (Sr-LTG) were grown using the Czochralski method. The thermal stress along the crystallographic c-axis decreased but that perpendicular to the c-axis increased by strontium substitution into the LTG crystal. The anisotropic thermal stress was reduced effectively. The Sr-LTG single crystal is a superior candidate material for pressure sensors usable at high temperatures.

Atomistic-Benchmarking towards a protocol development for rapid quantitative metrology of piezoelectric biomolecular materials

Biomolecular crystals are an emerging class of piezoelectric materials that are both biocompatible and biodegradable, which enables their use in biomedical applications and smart devices while ensuring eco-friendly production and disposal. However, accurate quantification of the piezoelectric response of soft sub-micron crystals remains a significant challenge, as conventional piezoelectric measurement techniques are suited to ceramics, thin films, and polymers. Here, we demonstrate the use of a novel piezoresponse force microscopy (PFM) methodology for robust, reliable quantification of the electromechanical response of biomolecular crystals. As a strong test of high accuracy and precision, we show that PFM, integrated with quantum mechanical (QM) density functional theory (DFT) calculations, can distinguish the piezoelectric responses of near-isopiezoelectric amino acid crystals. We show that a statistical approach, combined with experimental best practices, provides effective piezoelectric coefficients of biomolecular single crystals accurately and unambiguously. This work opens the door to high-throughput screening and characterisation of natural and engineered soft piezoelectric crystals for eco-friendly energy harvesters and biodegradable medical implants, reducing dependence on lead-based and rare-earth-containing piezoelectric materials.

Vibration Characteristics of Force Signal for Single Diamond Grit Scratching Process

Scratching force is a significant factor to evaluate the characteristics of single diamond grit scratching process. In this paper, experimental study was carried out to investigate the vibration characteristics of force signals during the scratching process. A precise multicomponent dynamometer is employed in the force measurement during a single diamond grit scratching on pure copper. The frequencies of the vibration section of force signals with different scratching parameters are calculated and analyzed. The influence of force signal vibration on the measuring accuracy of dynamometer is systematically analyzed further. The results show that higher scratching speed and larger scratching depth lead to larger vibration amplitudes of the force signals. Strong impact on the quartz piezoelectric crystal of dynamometer, which is produced indirectly by single diamond grit scratching process, leads to the vibration of scratching force signal. The first semi-sinusoidal force signal is the actual scratching force. The vibration of the scratching force signal has little effect on the measuring accuracy of the dynamometer.

Influence of Photoelastic and Piezoelectric Effects on the Energetic Characteristics of Transmission and Reflection Holograms in a Photorefractive Crystal

The surface of the normal component of the inverse tensor of the dielectric permittivity of a cubic photorefractive piezoelectric Bi12SiO20 crystal was constructed. A volume phase holographic grating with a wave vector along the $$ \left[1\overline{1}1\right] $$ crystallographic axis was recorded in this crystal. It is established that the combined action of the photoelastic and piezoelectric effects leads to an increasing normal component of the inverse tensor of the dielectric permittivity along the $$ \left[1\overline{1}1\right] $$ direction and a decreasing normal component of the inverse tensor of the dielectric permittivity in the perpendicular direction. It is revealed that the anisotropy of the contribution of the photoelastic and piezoelectric effects causes an increase in the output energetic characteristics (optimized in the azimuth of polarization of light waves) for the transmission hologram and their decrease for the reflection hologram.

Hand-generated piezoelectric mechanical-to-electrical energy conversion plasma

A transient spark discharge is an atmospheric pressure plasma that has applications in pollutant removal, medicine, water treatment, agriculture, bactericides, and nanomaterial synthesis. Conventional methods of generating transient sparks at atmospheric pressure usually require a high voltage input at nanosecond pulses. Piezoelectric crystals offer a path to creating plasma devices that do not require a high voltage power supply to generate high voltage outputs; they directly transform mechanical energy into electrical energy. This work examines a manually-operated piezoelectric mechanical-to-electrical energy conversion plasma device. Electrical characterization of the plasma discharge generated by this device shows that it behaves as a transient spark, discharging 0.96 mJ over approximately 30 ns, with consistent behavior across multiple consecutive discharges. Although this specific device had a low mechanical-to-plasma energy conversion efficiency of 1.54%, the piezoelectric crystal resets to an equilibrium condition after approximately 8 μs, which suggests that it could be operated with a mechanical input of up to nearly 125 kHz. This work shows the potential of generating plasma in off-the-grid situations using piezoelectric crystals. One particular application of a piezoelectric plasma device is for in situ pollution mitigation or plasma-enhanced combustion, embedding such a device on the high-frequency oscillating or rotating components of internal combustion engines and turbomachinery.

Petrov–Galerkin method for the band structure computation of anisotropic and piezoelectric phononic crystals

In this paper, the Petrov-Galerkin finite element interface method is modified to the vectorial form and applied to compute the band structure of phononic crystals with complicated scatterer geometry. Value-periodic subspace and projective grid are employed in this method. Complete mathematical model together with the continuity and equilibrium conditions on the scatterer interface as well as the Bloch-periodic boundary conditions on the unit cell are presented for these systems. We then apply this method to compute the band structure of three kinds of special phononic crystals: phononic crystal with anisotropic inclusions, phononic crystal containing piezoelectric materials and phononic crystal containing nano-piezoelectric materials. Taking advantage of asymmetric basis functions and non-body-fitted meshes, our method is suitable for the calculation and analysis of phononic crystals with complicated scatterer geometries. With plenty of numerical experiments, the accuracy and convergency of the proposed method is demonstrated. The influences of the rotation angle of anisotropic inclusion, complicated scatterer shape, filling fraction of the scatterers, and the rotation angle of the scatterers to the band structure of these three kinds of phononic crystals are investigated. This will provide a new perspective for the design and manufacture of phononic crystals with specific band structures.

Electrochemical biosensor for rapid detection of bacteria based on facile synthesis of silver wire across electrodes

The early detection of bacteria is of critical importance in addressing serious public health problems. Here, an electrochemical biosensor for rapid detection of bacteria based on facile synthesis of silver wire across electrodes was constructed. High-variable region of 16S rRNA of bacteria was used as biomarker. Polymerase-free synthesis of silver wire was introduced into electrochemical signal transduction to improve the sensitivity of electrochemical detection. The construction biosensor of proposed method is as follows: Metastable hairpin probe H1 was modified on electrode surface, biomarker can open the stem-loop structure of H1 and activates HCR. The alternate opening of the stem-loop structure of H1 and H2-AuNPs finally results in the formation of long double-stranded DNA-RNA (HCR products) -AuNPs. The formed AuNPs modified HCR products was blown in one direction using N2 to across the electrode gap. Using this HCR products as template, the silver wire was formed between the electrodes by silver deposition, and resulted in sharp change in electrical parameters of electrode. As the proof-of-concept work, multichannel series piezoelectric quartz crystal (MSPQC) was utilized as detector. The detection of Staphylococcus aureus in the concentration range from 50 to 107 CFU/mL within 100 min was achieved. The detection limit was 50 CFU/mL. Escherichia coli, Salmonella enteritidis, Listeria innocua, Pseudomonas aeruginosa and Streptococcus pneumoniae did not interfere the detection results. This newly proposed electrochemical biosensor is simple, rapid and exhibit high signal-to-noise ratio, it has great potential for being applied in food safety monitoring and clinical diagnosis.

Energy harvesting assessment with a coupled full car and piezoelectric model

Energy recovery from induced mechanical vibration in vehicle suspension based on piezoelectric harvesting and electromagnetic harvesting has been recently investigated by researchers. Piezoelectric vibration energy harvesting is a new technology that has been investigated for automotive applications due to the amount of wasted vibration from suspension systems. In this study, comprehensive simulations were conducted in order to investigate piezoelectric crystal application to vehicle suspension systems for the potential of harvested power quantification. For this purpose, a linear finite element of a piezoelectric disk was developed and integrated in the spring shock absorber assembling of a 7-DOF full car dynamic model. Equations of motion of these dynamic systems in the time domain were solved in the MATLAB® environment, where the road irregularities are introduced in the model, considering the Roll-pitch-bounce input mode. The RMS electric power responses for BaTiO3, PbTiO3, PbZrTiO3, PZT-5A and PZT-5H piezoelectric crystals were experimented and obtained in the context of energy harvesting. The energy density achieved in this study compared with the experimental results from the literature indicates the potential of the recovered power from the wasted vibration from suspension systems that could be used on embedded electronic devices

Accurate measurements of longitudinal temperature distribution of PPLN crystal in the process of second-harmonic generation.

Phase-matching temperature tuning curves and longitudinal temperature distribution of periodically poled lithium niobate (PPLN) crystal were measured in the process of second-harmonic generation (SHG) of 1070 nm pump wavelength using tiny transparent piezoelectric crystals as the temperature sensors. The temperatures of the crystal sensors placed along the PPLN length were determined directly by measuring the induced frequency shifts of their piezoelectric resonances, which were excited in a noncontact manner by a probe radio-frequency electric field. Such temperature sensors do not suffer additional heating conditioned by absorption of scattered radiation and also do not have any contact wires. Due to the high Q factors of piezoelectric resonances, the measurement accuracy of 0.05°C was achieved for a local determination of PPLN surface temperature during SHG. The self-consistent theoretical model that describes the SHG process in the presence of induced nonuniform temperature distribution of the nonlinear-optical crystal is introduced.

Shift photovoltaic current and magnetically induced bulk photocurrent in piezoelectric sillenite crystals

Recently, it has been shown how shift and ballistic currents in piezoelectric sillenite crystals Bi$_{12}$GeO$_{20}$ and Bi$_{12}$SiO$_{20}$ can be separated experimentally under the assumption that the shift component of the circular current is small. However, it has been claimed that the shift and ballistic currents cannot be quantified by this method, due to the magneto-photovoltaic effect caused either by the change of the crystal's spatial symmetry in the magnetic field or by the breaking of time-reversal symmetry. Presently, we report observations of photovoltaic currents in Bi$_{12}$SiO$_{20}$, excited by linearly- and circularly-polarized light under weak external magnetic field, as well as measurements of the corresponding photo-Hall signals. We demonstrate that the magneto-photovoltaic current constitutes a significant fraction of the measured current in the Hall direction for Bi$_{12}$SiO$_{20}$ under specific experimental conditions.

The effect of an ultrasound-activated needle tip tracker needle on the performance of sciatic nerve block on a soft embalmed Thiel cadaver.

In this study, we measured the performance of medical students and anaesthetists using a new tracker needle during simulated sciatic nerve block on soft embalmed cadavers. The tracker needle incorporates a piezo element near its tip that generates an electrical signal in response to insonation. A circle, superimposed on the ultrasound image surrounding the needle tip, changes size and colour according to the position of the piezo element within the ultrasound beam. Our primary objective was to compare sciatic block performance with the tracker switched on and off. Our secondary objectives were to record psychometrics, procedure efficiency, participant self-regulation and focused attention using eye-tracking technology. Our primary outcome measures were the number of steps successfully performed and the number of errors committed during each block. Videos were scored by trained experts using validated checklists. Sequential tracker activation and deactivation was randomised equally within subjects. With needle activation, steps improved in 10 (25%) subjects and errors reduced in six (15%) subjects. The most important steps were: needle tip identification before injection, OR (95%CI) 2.12 (1.61-2.80; p<0.001); and needle tip identification before advance of the needle, 1.80 (1.36-2.39; p<0.001). The most important errors were: failure to identify the needle tip before injection, 2.40 (1.78-3.24; p<0.001); and failure to quickly regain needle tip position when tip visibility was lost, 2.03 (1.5-2.75; p<0.001). In conclusion, needle-tracking technology improved performance in a quarter of subjects.

Highly Sensitive Magneto-Mechano-Electric Magnetic Field Sensor Based on Torque Effect

Magnetic field sensors based on the strain-mediated magnetoelectric (ME) coupling are usually bulky and energy-consuming due to the requirement for DC magnetic bias field, and the use of piezoelectric ceramics or single crystals cannot bear overlarge strain due to their fragility. Here, we demonstrate a stress-mediated ME sensor operating in torque mode without magnetic bias field. Combined with elastic layers, the NdFeB permanent magnets induce compressive stress on the piezoelectric layer via torque effect under a weak magnetic field. The contribution from d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">33</sub> piezoelectric coefficient is dominant to the ME effect, and a large ME voltage of 2480 mV is observed at 13.6 Oe. At the resonate frequency of 138.7 Hz, magnetoelectric coefficient is found to be as high as 6.08 V/cm Oe. Our results reveal that the proposed ME sensor mediated by stress is excellent in performance and reliable in durability, which is promising for magnetic sensor applications.

Preliminary Study: Comparative Analysis of the Effects of Ozone and Ultrasound on Streptococcus Mutans

ABSTRACT Streptococcus mutans is one of the principal pathogens of the human oral habitat, being one of the principal etiological agents of carious lesions. Ozone is a powerful oxidant, it has the ability to inactivate microorganisms in general, and ultrasound is an acoustic system generated through a piezoelectric crystal that also presents microbicidal effects. In the present study, a comparative analysis was made of the damage caused to Streptococcus mutans in vitro by ultrasound and ozone, through scanning electron microscopy (SEM) and atomic force microscopy (AF) analysis. In addition, flow cytometry was used to determine microbial viability and the formation of Reactive Oxygen Species (ROS) after the application of different techniques. The data obtained by means of microscopic analysis reveal that both ozone and ultrasound produce morphological alterations in bacteria, which become rod-shaped organisms. In addition to this deformation, on the microbial surface it was possible to identify crater-like impressions. In contrast, the irregularity of protuberances on the surface of the microbial wall was only detected when ozone was employed. Regarding the formation of ROS, it was observed that that ozone induces a significant growth (p < .05) of these molecules, while ultrasound does not present this effect. Ozone and ultrasound present microbicidal effects, however, ozone is more efficient.

Contactless Stimulation of Multiple Piezoelectric Devices Using Electric Field

The contactless energy transmission scheme using parallel-plate capacitor like structure has been explored which provides a platform for energization of multiple piezoelectric (piezo) components. In the proposed method, ac electric field lines produced by copper electrodes penetrate to the piezo components that are coaxially aligned and positioned in-between at certain distance away from each electrode. Consequently, the components are strongly excited at a point where the functioning electric field source frequency alike with the mechanical resonant frequency of the piezo components. The maximum output power corresponding to optimum load and resonant frequency acquired from the contactless energized multi piezo devices is better than that of power obtained from contactless energized single piezo component by this parallel-plate capacitor electric field generator. The testing results reveal the practicability of non contact stimulation/excitation of multi piezo components simultaneously through electric field.