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1
Boivin, Guillaume, Pierre Bélanger e Ricardo J. Zednik. "Characterization of Pure Face-Shear Strain in Piezoelectric α-Tellurium Dioxide (α-TeO2)". Crystals 10, n. 10 (15 ottobre 2020): 939. http://dx.doi.org/10.3390/cryst10100939.
Abstract (sommario):
Paratellurite, also known as α-tellurium dioxide, is a ceramic that is primarily employed for its interesting optical properties. However, this material’s crystal structure belongs to the 422 symmetry class that allows a unique piezoelectric behavior to manifest itself: deformation in pure face-shear. This means that crystal symmetry necessitates the piezoelectric tensor to have only a single non-zero coefficient, d123 = d14: such unique behavior has the potential to enable novel gyroscopic sensors and high-precision torsional microelectromechanical systems (MEMS) actuators, as pure face-shear can be used to induce pure torsion. Although α-TeO2 is one of the few known materials belonging to this symmetry class, considerable uncertainty in its single piezoelectric coefficient exists, with the few reported literature values ranging from 6.13 to 14.58 pC/N; this large uncertainty results from the difficulty in using conventional piezoelectric characterization techniques on paratellurite, limiting measurements to indirect methods. The novel applications that would be enabled by the adoption of this extraordinary material are frustrated by this lack of confidence in the literature. We therefore leverage, for the first time, a first-principles analytical physical model with electrochemical impedance spectroscopy (EIS) to determine, directly, the lone piezoelectric coefficient d123 = d14 = 7.92 pC/N.
2
Boivin, Guillaume, Pierre Bélanger e Ricardo J. Zednik. "Torsional Piezoelectric Strain in Monocrystalline Paratellurite". Materials Science Forum 879 (novembre 2016): 637–41. http://dx.doi.org/10.4028/www.scientific.net/msf.879.637.
Abstract (sommario):
Crystals of the 422 symmetry class exhibit interesting piezoelectric behavior, as their piezoelectric tensor has only a single non-zero coefficient, d123 = d14: such unique behavior has the potential to enable novel gyroscopic sensors and high-precision torsional MEMS actuators. Although alpha-phase tellurium dioxide (paratellurite, alpha-TeO2) is one of the few materials belonging to this symmetry class, this material has been primarily studied for its interesting optical properties. Indeed, a large uncertainty in the piezoelectric coefficient of paratellurite exists, with d123 measurements on single crystals ranging from 8.13 pC/N to 14.58 pC/N; this large uncertainty results from the difficulty in using conventional piezoelectric characterization techniques on paratellurite, and impedes adoption of this extraordinary material. The present study characterizes the piezoelectric behavior of this interesting material using two independent techniques, (1) a three dimensional laser Doppler interferometer system, and (2) electrochemical impedance spectroscopy (EIS). The experimental results are analyzed using numerical simulations for dynamic excitation conditions over a frequency range of 20 Hz to 200 kHz.
3
Mallah, Abdulrahman, Mourad Debbichi, Mohamed Houcine Dhaou e Bilel Bellakhdhar. "Structural, Mechanical, and Piezoelectric Properties of Janus Bidimensional Monolayers". Crystals 13, n. 1 (10 gennaio 2023): 126. http://dx.doi.org/10.3390/cryst13010126.
Abstract (sommario):
In the present work, the noncentrosymmetric 2D ternary Janus monolayers Al2XX’(X/X’ = S, Se, Te and O), Si2XX’(X/X’ = P, As, Sb and Bi), and A2PAs(A = Ge, Sn and Pb) have been studied based on first-principles calculations. We find that all the monolayers exhibit in-plane d12, and out-of-plane d13 piezoelectric coefficients due to the lack of reflection symmetry with respect to the central A atoms. Moreover, our calculations show that Al2OX(T = S, Se, Te) chalcogenide monolayers have higher absolute in-plane piezoelectric coefficients. However, the highest out-of-plane values are achieved in the Si2PBi monolayer, larger than those of some advanced piezoelectric materials, making them very promising transducer materials for lightweight and high-performance piezoelectric nanodevices.
4
Berik, Pelin, e Peter L. Bishay. "Parameter Identification of the Nonlinear Piezoelectric Shear d15 Coefficient of a Smart Composite Actuator". Actuators 10, n. 7 (19 luglio 2021): 168. http://dx.doi.org/10.3390/act10070168.
Abstract (sommario):
The objective of this work is to characterize the nonlinear dependence of the piezoelectric d15 shear coefficient of a composite actuator on the static electric field and include this effect in finite element (FE) simulations. The Levenberg-Marquardt nonlinear least squares optimization algorithm implemented in MATLAB was applied to acquire the piezoelectric shear coefficient parameters. The nonlinear piezoelectric d15 shear constant of the composite actuator integrated with piezoceramic d15 patches was obtained to be 732 pC/N at 198 V. The experimental benchmark was simulated using a three-dimensional piezoelectric FE model by taking piezoelectric nonlinearity into consideration. The results revealed that the piezoelectric shear d15 coefficient increased nonlinearly under static applied electric fields over 0.5 kV/cm. A comparison between the generated transverse deflections of the linear and nonlinear FE models was also performed.
5
Lei, Heng, Tao Ouyang, Chaoyu He, Jin Li e Chao Tang. "Monolayer group IV monochalcogenides T-MX (M = Sn, Ge; X = S, Se) with fine piezoelectric performance and stability". Applied Physics Letters 122, n. 6 (6 febbraio 2023): 062903. http://dx.doi.org/10.1063/5.0135704.
Abstract (sommario):
Monolayer group monochalcogenides (MX; M = Sn, Ge; X = S, Se) in the orthogonal α-phase are excellent piezoelectric materials. In this study, a configuration with bonding features similar to the α-phase is proposed (T-phase) for monolayer MX using the first-principles method. Based on the modern theory of polarization, as implemented in Vienna Ab initio Simulation Package, the T-phase is determined to be an excellent piezoelectric phase for monolayer MX. The in-plane piezoelectric coefficient d11 of T-SnS is 452.3 pm/V, which is larger than that reported for most two-dimensional binary compounds in the α-phase, including α-SnSe (∼250 pm/V). The large piezoelectric coefficients of T-MX mainly stem from its distinctive puckered configuration, which make it extraordinarily flexible along the polarization direction. The study results suggest a possibility for designing high piezoelectric coefficient materials with MX, and the potential application of T-MX in the fields of energy collection and nanoelectromechanical systems needs to be analyzed in future studies.
6
Gao, Chang Yin, e Wan Quan Li. "Research on the Bending Charge Sensitivity Distribution of Piezoelectric Quartz". Applied Mechanics and Materials 48-49 (febbraio 2011): 980–83. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.980.
Abstract (sommario):
In order to enhance measurement precision of the piezoelectric micro-actuator, by means of the transformation rule of tensor the research on the Bending Charge Sensitivity Distribution of Piezoelectric Quartz is conducted. First by the theories of elasticity and electromagnetism the torsion stress and bound charge are calculated, and the charge measured by the detection electrodes is obtained, which depend on the piezoelectric coefficient d12. Then using the transformation rule of tensor the piezoelectric coefficient d12 in the new coordinate system is calculated, and according to the unrestrained multipurpose optimization method the optimization Cut is obtained. Finally a special designed experiment is performed, and the experimental results show that the bound charge produced by the optimized Cut is about twice larger than that primitive Cut. This research on the bending charge sensitivity will provide a theoretical foundation for disposing the detection electrodes of a new piezoelectric micro-actuator
7
Altammar, Hussain, Anoop Dhingra e Nathan Salowitz. "Damage Detection Using d15 Piezoelectric Sensors in a Laminate Beam Undergoing Three-Point Bending". Actuators 8, n. 4 (29 settembre 2019): 70. http://dx.doi.org/10.3390/act8040070.
Abstract (sommario):
A major inhibition to the widespread use of laminate structures is the inability of nondestructive testing techniques to effectively evaluate the bondline integrity. This work proposes and analyzes a bondline-integrity health monitoring approach utilizing shear-mode (d15) piezoelectric transducers. The d15 transducers were embedded in the bondlines of symmetric laminate structures to monitor and evaluate the bondline integrity using ultrasonic inspection. The d15 piezoelectric transducers made of lead zirconate titanate (PZT) enabled ultrasonic inspection of bonds by actuating and sensing antisymmetric waves in laminate structures. Design considerations, fabrication process, and experimental methods for testing a laminate specimen are presented. Designs included bondline-embedded d15 PZT piezoelectric transducers with surface-mounted transverse (d31) piezoelectric transducers for signal comparison. Defects in the bondline were created by a quasi-static three-point bending test, with results showing the ability of d15 piezoelectric transducers to detect bondline damage. Two damage indices based on Pearson correlation coefficient and normalized signal energy were implemented to evaluate the presence of damage and its severity. The experimental results demonstrate the ability of bondline-embedded d15 piezoelectric transducers to be used as actuators and sensors for ultrasonic health monitoring of bondline integrity. A comparison between surface-mounted d31 PZT and bondline-embedded d15 PZT sensors was also conducted. It was seen that signals sensed by bondline-embedded d15 PZTs showed higher distortion due to bondline defects compared with the sensed signals from the surface-mounted d31 PZT.
8
Jiang, Chao, Feifei Chen, Fapeng Yu, Shiwei Tian, Xiufeng Cheng, Shujun Zhang e Xian Zhao. "Thermal Expansion and Electro-Elastic Features of Ba2TiSi2O8 High Temperature Piezoelectric Crystal". Crystals 9, n. 1 (24 dicembre 2018): 11. http://dx.doi.org/10.3390/cryst9010011.
Abstract (sommario):
A high-quality Ba2TiSi2O8 (BTS) single crystal was grown using the Czochralski (Cz) pulling method. The thermal expansion and electro-elastic properties of BTS crystal were studied for high temperature sensor applications. The relative dielectric permittivities ε 11 T / ε 0 and ε 33 T / ε 0 were determined to be 16.3 and 11.8, while the piezoelectric coefficients d15, d31, d33 were found to be 17.8, 2.9, and 4.0 pC/N, respectively. Temperature dependence of electro-elastic properties were investigated, where the variation of elastic compliance s 55 E (= s 44 E ) was found to be <6% over temperature range of 20–700 °C. Taking advantage of the anisotropic thermal expansion, linear thermal expansion comparable to insulating alumina ceramic was achieved over temperature range up to 650 °C. The optimum crystal cut with large effective piezoelectric coefficient (>8.5 pC/N) and linear thermal expansion coefficient (8.03 ppm/°C) achieved for BTS crystal along the (47°, φ) direction (φ is arbitrary in 0–360°), together with its good temperature stability up to 650 °C, make BTS crystal a promising candidate for high temperature piezoelectric sensors.
9
Zhu, Yuankun, Xuejun Zheng, Lei Li, Yuangen Yu, Xun Liu e Jianguo Chen. "Evaluation of shear piezoelectric coefficient d15 of piezoelectric ceramics by using piezoelectric cantilever beam in dynamic resonance". Ferroelectrics 520, n. 1 (18 novembre 2017): 202–11. http://dx.doi.org/10.1080/00150193.2017.1388838.
10
Gu, W. Y., W. Y. Pan e L. E. Cross. "Direct measurement of the piezoelectric shear coefficient d15 under non-resonant conditions". Materials Letters 8, n. 1-2 (aprile 1989): 3–5. http://dx.doi.org/10.1016/0167-577x(89)90085-2.
11
Kahn, M., R. P. Ingel e D. Lewis. "On the determination of the piezoelectric shear coefficient,d15, in a PZT ceramic". Ferroelectrics 102, n. 1 (febbraio 1990): 225–34. http://dx.doi.org/10.1080/00150199008221482.
12
Chen, Feifei, Chao Jiang, Fapeng Yu, Xiufeng Cheng e Xian Zhao. "Investigation of Electro-Elastic Properties for LN Single Crystals at Low Temperature". Applied Sciences 11, n. 16 (11 agosto 2021): 7374. http://dx.doi.org/10.3390/app11167374.
Abstract (sommario):
Lithium niobate crystals (LiNbO3, LN) are multifunctional crystal materials with many outstanding properties. In this work, the electro-elastic properties of LN single crystals were explored at temperatures from −150 °C to 150 °C. The temperature dependences of dielectric permittivities, elastic compliances, electromechanical coupling factors and piezoelectric coefficients were determined using the impedance method. The LN crystals possessed large dielectric permittivities, the ε11T/ε0 and ε33T/ε0 were 83.2 and 29.4 at room temperature, respectively. The elastic compliances s11, s13, s33 and s44 presented a positive increase as the temperature increased, and the variations were 5.0%, 8.2%, 4.6% and 5.4%, respectively, showing a good temperature stability. Moreover, the temperature dependence of the electromechanical coupling factors and piezoelectric coefficients for different vibration modes were studied with a temperature range from −150 °C to 150 °C, where the thickness shear vibration mode d15 presented a large piezoelectric response and minimal temperature variation.
13
Toporovsky, Vladimir, Vadim Samarkin, Alexis Kudryashov, Ilya Galaktionov, Alexander Panich e Anatoliy Malykhin. "Investigation of PZT Materials for Reliable Piezostack Deformable Mirror with Modular Design". Micromachines 14, n. 11 (28 ottobre 2023): 2004. http://dx.doi.org/10.3390/mi14112004.
Abstract (sommario):
This article presents a study of the electrophysical properties of a piezoceramic material for use in adaptive optics. The key characteristics that may be important for the manufacturing of piezoelectric deformable mirrors are the following: piezoelectric constants (d31, d33, d15), capacitance, elastic compliance values s for different crystal directions, and the dielectric loss tangent (tgδ). Based on PZT ceramics, the PKP-12 material was developed with high values of the dielectric constant, piezoelectric modulus, and electromechanical coupling coefficients. The deformable mirror control elements are made from the resulting material—piezoceramic combs with five individual actuators in a row. In this case, the stroke of the actuator is in the range of 4.1–4.3 microns and the capacitance of the actuator is about 12 nF.
14
Afanasiev, Mikhail S., Dmitry A. Kiselev, Alexey A. Sivov e Galina V. Chucheva. "Synthesis and piezoelectric properties of freestanding ferroelectric films based on barium strontium titanate". Modern Electronic Materials 9, n. 4 (12 dicembre 2023): 163–68. http://dx.doi.org/10.3897/j.moem.9.4.115181.
Abstract (sommario):
In this work, the membrane structures based on lead-free ferroelectric barium strontium titanate with composition Ba0.8Sr0.2TO3 (BSTO) were fabricated by a magnetron sputtering method. The formation of a single-phase Ba0.8Sr0.2TO3 with thickness of 300 nm sintered on Si substrate is confirmed by XRD analysis. It is shown that films without a silicon substrate exhibit ferroelectric and piezoelectric properties. The piezoelectric and ferroelectric behaviors of BSTO thin film without a silicon substrate were confirmed through a piezoelectric force microscopy and Kelvin probe force microscopy and measurements of the effective piezoelectric coefficients (d33 and d15). Images of the residual potential of polarized areas have been obtained on the membranes, which are stable over time despite the absence of a lower electrode. Additionally, a local of ferroelectric hysteresis loop has been observed. A combination of the structural and piezoelectric measurements reveals that it possible to create freestanding ferroelectric films based on Ba0.8Sr0.2TO3 system, establishing it as a promising candidate for high-performance electromechanical applications.
15
Afanasiev, Mikhail S., Dmitry A. Kiselev, Alexey A. Sivov e Galina V. Chucheva. "Synthesis and piezoelectric properties of freestanding ferroelectric films based on barium strontium titanate". Modern Electronic Materials 9, n. 4 (12 dicembre 2023): 163–68. http://dx.doi.org/10.3897/j.moem.9.115181.
Abstract (sommario):
In this work, the membrane structures based on lead-free ferroelectric barium strontium titanate with composition Ba0.8Sr0.2TO3 (BSTO) were fabricated by a magnetron sputtering method. The formation of a single-phase Ba0.8Sr0.2TO3 with thickness of 300 nm sintered on Si substrate is confirmed by XRD analysis. It is shown that films without a silicon substrate exhibit ferroelectric and piezoelectric properties. The piezoelectric and ferroelectric behaviors of BSTO thin film without a silicon substrate were confirmed through a piezoelectric force microscopy and Kelvin probe force microscopy and measurements of the effective piezoelectric coefficients (d33 and d15). Images of the residual potential of polarized areas have been obtained on the membranes, which are stable over time despite the absence of a lower electrode. Additionally, a local of ferroelectric hysteresis loop has been observed. A combination of the structural and piezoelectric measurements reveals that it possible to create freestanding ferroelectric films based on Ba0.8Sr0.2TO3 system, establishing it as a promising candidate for high-performance electromechanical applications.
16
Ivanov, Maxim, Ohheum Bak, Svitlana Kopyl, Semen Vasilev, Pavel Zelenovskiy, Vladimir Shur, Alexei Gruverman e Andrei Kholkin. "High Resolution Piezoresponse Force Microscopy Study of Self-Assembled Peptide Nanotubes". MRS Advances 2, n. 02 (27 dicembre 2016): 63–69. http://dx.doi.org/10.1557/adv.2016.658.
Abstract (sommario):
ABSTRACT Peptide nanotubes based on short dipeptide diphenylalanine (FF) attract a lot of attention due to their unique physical properties ranging from strong piezoelectricity to extraordinary mechanical rigidity. In this work, we present the results of high-resolution Piezoresponse Force Microscopy (PFM) measurements in FF microtubes prepared from the solution. First in-situ temperature measurements show that the effective shear piezoelectric coefficient d15 (proportional to axial polarization) significantly decreases (to about half of the initial value) under heating up to 100 oC. The piezoresponse becomes inhomogeneous over the surface being higher in the center of the tubes. Further, PFM study of a composite consisting of FF microtubes and reduced graphene oxide (rGO) was performed. We show that piezoelectric properties of peptide microtubes are significantly modified and radial (vertical) piezoresponse appears in the presence of rGO as confirmed via PFM analysis. The results are rationalized in terms of molecular approach in which π – π molecular interaction between rGO and dipeptide is responsible for the appearance of radial component of polarization in such hybrid structures.
17
Wu, Yingying, Yun Ou, Jinlin Peng e Chihou Lei. "Phase Structures, Electromechanical Responses, and Electrocaloric Effects in K0.5Na0.5NbO3 Epitaxial Film Controlled by Non-Isometric Misfit Strain". Crystals 13, n. 9 (29 agosto 2023): 1321. http://dx.doi.org/10.3390/cryst13091321.
Abstract (sommario):
Environmentally friendly lead-free K1-xNaxNbO3 (KNN) ceramics possess electromechanical properties comparable to lead-based ferroelectric materials but cannot meet the needs of device miniaturization, and the corresponding thin films lack theoretical and experimental studies. To this end, we developed the nonlinear phenomenological theory for ferroelectric materials to study the effects of non-equiaxed misfit strain on the phase structure, electromechanical properties, and electrical response of K0.5Na0.5NbO3 epitaxial films. We constructed in-plane misfit strain (u1−u2) phase diagrams. The results show that K0.5Na0.5NbO3 epitaxial film under non-equiaxed in-plane strain can exhibit abundant phase structures, including orthorhombic a1c, a2c, and a1a2 phases, tetragonal a1, a2, and c phases, and monoclinic r12 phases. Moreover, in the vicinity of a2c−r12, a1c−c, and a1a2−a2 phase boundaries, K0.5Na0.5NbO3 epitaxial films exhibit excellent dielectric constant ε11, while at a2c−r12 and a1c−c phase boundaries, a significant piezoelectric coefficient d15 is observed. It was also found that high permittivity ε33 and piezoelectric coefficients d33 exist near the a2c−a2, a1a2−r12, and a1c−a1 phase boundaries due to the existence of polymorphic phase boundary (PPB) in the KNN system, which makes it easy to polarize near the phase boundaries, and the polarizability changes suddenly, leading to electromechanical enhancement. In addition, the results show that the K0.5Na0.5NbO3 thin films possess a large electrocaloric response at the phase boundary at the a1a2−r12 and a1c−a1 phase boundaries. The maximum adiabatic temperature change ΔT is about 3.62 K when the electric field change is 30 MV/m at room temperature, which is significantly enhanced compared with equiaxed strain. This study provides theoretical guidance for obtaining K1−xNaxNbO3 epitaxial thin films with excellent properties.
18
Rana, Gourav, Raveena Gupta e Chandan Bera. "Theoretical study of phonon and electron transport in low band gap Janus MXene monolayer MoWCO2 for thermoelectric application". Applied Physics Letters 122, n. 6 (6 febbraio 2023): 063902. http://dx.doi.org/10.1063/5.0134617.
Abstract (sommario):
A theoretical study is performed on narrow bandgap Janus monolayer MoWCO2 using the density functional theory and the Boltzmann transport equation. The scattering rate is calculated for electron–phonon, phonon–phonon, phonon-boundary, and electron-boundary scattering. It has a power factor (6.5 × 103 [Formula: see text]W/mK2) for p-type and (1.5 × 103 [Formula: see text]W/mK2) for n-type at T = 700 K. A strong effect of surface scattering is observed in phonon transport, and lattice thermal conductivity is reduced to 65 W/m K from 308 W/m K at T = 300K for 1 [Formula: see text]m width (L) of ribbon. In contrast, there is no change observed in electrical conductivity. This reduction in thermal conductivity improves the thermoelectric figure of merit to 0.33 (p-type) and 0.08 (n-type) at T = 700 K for L = 10 nm from 0.04 (p-type) and 0.01 (n-type). The obtained Young's modulus and Poisson's ratio are 244 N/m and 0.55, respectively, indicating that the material can be deformed under small strain. The obtained in-plane piezoelectric coefficients are e11 = 268 pC/m and d11 = 1.6 pm/V. This indicates the material will be suitable for wearable thermoelectric devices and sensor applications.
19
BEN ACHOUR, Mohamed Aymen, Mohamed Rguiti, Cédric Samuel, Sophie Barrau, Marie-France Lacrampe e Christian Courtois. "Energy harvesting by uniaxially stretched Poly(lactic acid) film at low strain frequency for powering wearable sensors: Experimental results and theoretical extrapolation." Smart Materials and Structures, 26 maggio 2023. http://dx.doi.org/10.1088/1361-665x/acd972.
Abstract (sommario):
Abstract Poly(lactic acid) (PLA) is an eco-friendly and low-cost polymer with an shear piezoelectricity classically induced by a simple uniaxial stretching and without poling process. These interesting properties make PLA as a good candidate to replace the widely used PVDF piezoelectric polymer, particularly for flexible energy harvesting applications aiming to power wearable sensors. In this work, PLA films were fabricated by a simple extrusion and uniaxial stretching process. The energy harvesting efficiency of the PLA films were characterized using a test bench designed for flexible materials based on the piezoelectric 31-mode at low frequencies. The measurements on PLA films show a maximum electrical power about 3.7 µW harvested by applying a strain of 1% amplitude at 20 Hz. A theoretical model was developed based on electromechanical parameters to ascertain the energy harvesting behaviour of PLA. The validated model was also helpful to estimate the electrical output power from PLA films by increasing the active surface area and for the potential improvement of piezoelectric shear coefficient (d14). The optimized PLA film could then produce an electrical power comparable to that produced by PVDF film in the same mechanical excitation conditions. This study then highlights the potential of the developed model to estimate the electrical power generated by piezoelectric polymer film for energy harvesting applications.
20
Khandelwal, Upanya, Rama Satya Sandilya, Rajeev Kumar Rai, Deepak Sharma, Smruti Rekha Mahapatra, Debasish Mondal, Navakanta Bhat et al. "Large electro-opto-mechanical coupling in VO2 neuristors". Applied Physics Reviews 11, n. 2 (17 aprile 2024). http://dx.doi.org/10.1063/5.0169859.
Abstract (sommario):
Biological neurons are electro-mechanical systems, where the generation and propagation of an action potential are coupled to the generation and transmission of an acoustic wave. Neuristors, such as VO2, characterized by insulator-metal transition (IMT) and negative differential resistance, can be engineered as self-oscillators, which are good approximations of biological neurons in the domain of electrical signals. In this study, we show that these self-oscillators are coupled electro-opto-mechanical systems, with better energy conversion coefficients than the conventional electro-mechanical or electro-optical materials. This is due to the significant contrast in the material's resistance, optical refractive index, and density across the induced temperature range in a Joule heating driven IMT. We carried out laser interferometry to measure the opto-mechanical response while simultaneously driving the devices electrically into self-oscillations of different kinds. We analyzed films of various thicknesses, engineered device geometry, and performed analytical modeling to decouple the effects of refractive index change vis-à-vis mechanical strain in the interferometry signal. We show that the effective piezoelectric coefficient (d13*) for our neuristor devices is 660 ± 20 pm/V, with a 31% internal energy conversion efficiency, making them viable alternatives to Pb-based piezoelectrics for MEMS applications. Furthermore, we show that the effective electro-optic coefficient (r13*) is ∼22 nm/V, which is much larger than that in thin-film and bulk Pockels materials.
21
Xu, Furong, Songli Dai, Weifu Cen, Qinghua Zeng e Zean Tian. "Study on the piezoelectric properties and the mechanism of strain-regulated piezoelectricity in flexible Janus monolayers Cr2X3Y3 (X/Y=Cl, Br,I)". Physica Scripta, 11 gennaio 2024. http://dx.doi.org/10.1088/1402-4896/ad1da0.
Abstract (sommario):
Abstract Piezoelectric materials hold significant promise in piezoelectric electronics and piezoelectric optoelectronics. As a new member of this family, the 2D Janus structures characterized by central symmetry breaking have attracted much attention due to the out-of-plane piezoelectric effects. In this work, the mechanical, piezoelectric properties, and the strain regulation mechanism of Juans structure material (Cr2X3Y3, X/Y = Cl, Br, I) are systematically investigated by the first-principles methods. The calculated mechanical properties show that Cr2X3Y3 with a lower Young’s modulus of 27.31~29.76 N/m is more sensitive to applied stresses, theoretically exhibiting exceptional piezoelectric properties. The in-plane piezoelectric coefficients d11 for Cr2Br3Cl3, Cr2I3Cl3, and Cr2I3Br3 are 4.92, 9.89, and 7.86 pm/V, respectively; the out-of-plane piezoelectric coefficients d31 are 1.13, 2.33, and 1.64 pm/V, respectively. Cr2I3Cl3 has the highest values of d11 and d31 due to the large electronegativity difference between iodine and chlorine atoms. Based on the analysis, it can be deduced that Cr2X3Y3 demonstrates substantial piezoelectric responses in both in- and out-of-plane, with potential strain regulation effects. The d31 values of Cr2I3Cl3 show an approximately linear relationship to strain in the range from -2% to 4% and remain consistently above 2.10 pm/V across a broader range of strain from -4% to 6%, underscoring its robustness to strain. Our study indicates that two-dimensional Janus Cr2X3Y3 monolayers would emerge as promising candidates for diverse applications in multifunctional electronic devices.
22
Yarajena, Sai Saraswathi, Rabindra Biswas, Varun Raghunathan e Akshay K. Naik. "Quantitative probe for in-plane piezoelectric coupling in 2D materials". Scientific Reports 11, n. 1 (29 marzo 2021). http://dx.doi.org/10.1038/s41598-021-86252-9.
Abstract (sommario):
AbstractPiezoelectric response in two-dimensional (2D) materials has evoked immense interest in using them for various applications involving electromechanical coupling. In most of the 2D materials, piezoelectricity is coupled along the in-plane direction. Here, we propose a technique to probe the in-plane piezoelectric coupling strength in layered nanomaterials quantitively. The method involves a novel approach for in-plane field excitation in lateral Piezoresponse force microscopy (PFM) for 2D materials. Operating near contact resonance has enabled the measurement of the piezoelectric coupling coefficients in the sub pm/V range. Detailed methodology for the signal calibration and the background subtraction when PFM is operated near the contact resonance of the cantilever is also provided. The technique is verified by estimating the in-plane piezoelectric coupling coefficients (d11) for freely suspended MoS2 of one to five atomic layers. For 2D-MoS2 with the odd number of atomic layers, which are non-centrosymmetric, finite d11 is measured. The measurements also indicate that the coupling strength decreases with an increase in the number of layers. The techniques presented would be an effective tool to study the in-plane piezoelectricity quantitatively in various materials along with emerging 2D-materials.
23
Xie, Yapeng, Silie Fu, Linhan Wang, gengrun gan, Xue‑Lian Gao, Chun‑An Wang, Yu-Lin Chen e Jia-Ying Chen. "Piezoelectric characteristics of doped β-Ga2O3 monolayer: a first-principles study". Physica Scripta, 26 marzo 2024. http://dx.doi.org/10.1088/1402-4896/ad37e1.
Abstract (sommario):
Abstract Two-dimensional (2D) piezoelectric materials have been widely concerned because of their important applications in nano-piezoelectric generators. Finding two-dimensional materials with a large piezoelectric effect is still a great challenge. In this work, the inversion center of the β-Ga2O3 monolayer was broken by substitutional doping. Not only the in-plane piezoelectric effect but also the uncommon out-of-plane piezoelectric effect is induced in the doped β-Ga2O3 monolayer. In addition, we analyzed the cause of the piezoelectric effects from their electronic properties. The values of out-of-plane (in-plane) piezoelectric coefficient for Cu-doped and Al-doped β-Ga2O3 reach -4.04 (3.95) pm/V and -2.91 (0.37) pm/V, respectively. The results are comparable with those of the commonly used bulk piezoelectric materials such as α-quartz (d11 = 2.3 pm/V), AlN (d33 = 5.1 pm/V), and GaN (d33 = 3.1 pm/V), even though they are both two-dimensional structures. Our study shows a great potential application of doped β-Ga2O3 monolayer in micro and nano-electromechanical devices such as smart wearables, sensors, energy converters, and micro energy collectors.
24
Xiao, Yu, Sviatoslaw Karnaoukh e Nan Wu. "Design and analysis of a d15 mode piezoelectric energy generator using friction-induced vibration". Smart Materials and Structures, 16 febbraio 2023. http://dx.doi.org/10.1088/1361-665x/acbcb1.
Abstract (sommario):
Abstract Research works have been conducted on transverse and longitudinal mode piezoelectric energy generation to collect energy from ambient vibrations. However, the inconsistency with the frequency of the energy source and low output power density remain problems for high energy output. In this work, we propose a shear mode piezoelectric energy generator, which utilizes the friction-induced vibration and high shear mode piezoelectric coefficient to improve the energy output. A piezoelectric coupled friction-induced vibration mathematical model is developed to accurately calculate the dynamic vibration response and voltage output. The dynamic voltage response is validated by experiment, and it proves the possibility of continuous friction-induced high-frequency vibration. The energy generation process is evaluated by transient charging simulation of a storage capacitor through an iteration process, which was experimentally validated in the literature. Parameter studies have been conducted to investigate the influences of the piezoelectric patch dimensional parameters, vibration system parameters, friction model parameters, methods of electrical connections, and different piezoelectric materials on the energy generation performance to provide guidance for better design. Under ideal experiment conditions with proper parameters, a volume of 6.25×10^(-8) m3 PZT4 piezoelectric material indicates RMS charging power density of 5.38×10^3 Wm-3 and 4.70×10^3 Wm-3 with electrically in parallel and electrically in series, respectively. While using the same amount of material and structural setup, the single crystal PMN-PT piezoelectric material shows RMS charging power density of 2.72×10^4 Wm-3 and 2.58×10^4 Wm-3 with electrically in parallel and electrically in series, correspondingly. These promising results demonstrate that close to W-level RMS charging power output may be realized by structure optimization of energy generator design and incorporating multiple generators together for operation. Possible incorporation into vehicle braking systems can be considered to utilize the wasted friction energy, and it may offer an energy supply for low-power wireless devices.
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Yuan, Hui, Pierre‐Andre Cazade, Shuaikang Zhou, Linda J. W. Shimon, Chengqian Yuan, Dan Tan, Cunshun Liu et al. "Molecular Engineering of Ordered Piezoelectric Sulfonic Acid‐Containing Assemblies". Small, 10 dicembre 2023. http://dx.doi.org/10.1002/smll.202309493.
Abstract (sommario):
AbstractSulfonic acid‐containing bioorganic monomers with wide molecular designability and abundant hydrogen bonding sites hold great potential to design diverse functional biocrystals but have so far not been explored for piezoelectric energy harvesting applications due to the lack of strategies to break the centrosymmetry of their assemblies. Here, a significant molecular packing transformation from centrosymmetric into non‐centrosymmetric conformation by the addition of an amide terminus in the sulfonic acid‐containing bioorganic molecule is demonstrated, allowing a high electromechanical response. The amide‐functionalized molecule self‐assembles into a polar supramolecular parallel β‐sheet‐like structure with a high longitudinal piezoelectric coefficient d11 = 15.9 pm V−1 that produces the maximal open‐circuit voltage of >1 V and the maximal power of 18 nW in nanogenerator devices pioneered. By contrast, molecules containing an amino or a cyclohexyl terminus assemble into highly symmetric 3D hydrogen bonding diamondoid‐like networks or 2D double layer structures that show tunable morphologies, thermostability, and mechanical properties but non‐piezoelectricity. This work not only presents a facile approach to achieving symmetry transformation of bioorganic assemblies but also demonstrates the terminal group and the property correlation for tailor‐made design of high‐performance piezoelectric biomaterials.
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Graafsma, Heinz, Jarek Majewski, David Cahen e Philip Coppens. "Ionic Displacements and Piezoelectric Constants of AgGaS2 from X-Ray Diffraction of a Crystal in an External Electric Field." MRS Proceedings 210 (1990). http://dx.doi.org/10.1557/proc-210-639.
Abstract (sommario):
AbstractWe have determined the displacements of the ions and the changes in cell parameters which occur on application of an electric field to a crystal of AgGaS2, using a three-step modulation method. The shifts in Bragg angle of 14 reflections, due to a fieldof 2.6 x 106 V/m applied nearly parallel to [221], were used to refine the change in cell parameters. The resulting piezo-electric coefficients are d14=d25 =8.8 (0.9) 10-12 C/N and d36=7.6 (1.8) 10-12 C/N. This leads to a value of 4.8 (0.5) pC/Nfor the piezoelectric constant in the [221] direction which compares well with a value of 5-6 10-12 C/N determined by other methods. The ionic displacements were studied on a second sample, with E=2.6x 106 V/m in adirection parallel to [110]. Very small, but significant a and b directiondisplacements were observed for all atoms, whereas the displacements in the c direction were negligible as expected. Relative to the sulfur framework, the Ga ion displacement is considerably larger than that of the Ag ions.