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Results for “PIEZOELECTRIC CRYSTAL”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Enhanced piezoelectricity from highly polarizable oriented amorphous fractions in biaxially oriented poly(vinylidene fluoride) with pure β crystals

Piezoelectric polymers hold great potential for various electromechanical applications, but only show low performance, with |d 33 |< 30 pC/N. We prepare a highly piezoelectric polymer (d 33 = -62 pC/N) based on a biaxially oriented poly(vinylidene fluoride) (BOPVDF, crystallinity = 0.52). After unidirectional poling, macroscopically aligned samples with pure β crystals are achieved, which show a high spontaneous polarization (P s ) of 140 mC/m 2 . Given the theoretical limit of P s,β = 188 mC/m 2 for the neat β crystal, the high P s cannot be explained by the crystalline-amorphous two-phase model (i.e., P s,β = 270 mC/m 2 ). Instead, we deduce that a significant amount (at least 0.25) of an oriented amorphous fraction (OAF) must be present between these two phases. Experimental data suggest that the mobile OAF resulted in the negative and high d 33 for the poled BOPVDF. The plausibility of this conclusion is supported by molecular dynamics simulations.

36 MATERIALS SCIENCE↗
DOE OSTI2020

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 magnetophotovoltaic 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. Further, we demonstrate that the magnetophotovoltaic current constitutes a significant fraction of the measured current in the Hall direction for Bi 12 SiO 20 under specific experimental conditions.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Conducting metal oxides integrated with the surface acoustic wave (SAW) sensor platform

One or more embodiments relates a single port surface acoustic wave sensor (SAW) device adapted for use in a wide range of operational temperatures and gas phase chemical species. The device includes a piezoelectric crystal substrate; at least one interdigitated electrode/transducer (IDT) positioned on the piezoelectric crystal substrate; and at least one conducting metal oxide film positioned on the piezoelectric crystal substrate and in communication with at least the IDT.

Ohodnicki, Jr., Paul R.↗
DOE OSTI2024

Electrical de-poling and re-poling of relaxor-PbTiO 3 piezoelectric single crystals without heat treatment

Re-poling of unexpected partially depoled piezoelectric materials conventionally needs to be first fully depoled through annealing above their Curie temperature to revive piezoelectric performances. Here, we investigated de-poling and re-poling of Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 single crystals under electric fields at room temperature. We found that alternating current electric fields with amplitudes near the coercive field at low frequencies (<10 Hz) can be employed to successfully depolarize poled crystals at room temperature. We also demonstrated a reversible polarization switching process with a relaxor-PbTiO 3 single crystal ultrasound transducer without device performance degradations. This experimental observation is supported by phase-field simulation, showing that alternating current electric fields can readily induce de-poling at room temperature, while direct current electric fields induce a transient depoled state only within an uncontrollable short period of time. The findings suggest new strategies for unprecedented in-device tailoring of the polarization states of ferroelectric materials.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Autonomous self-repair in piezoelectric molecular crystals

Living tissue uses stress-accumulated electrical charge to close wounds. Self-repairing synthetic materials, which are typically soft and amorphous, usually require external stimuli, prolonged physical contact, and long healing times. We overcome many of these limitations in piezoelectric bipyrazole organic crystals, which recombine following mechanical fracture without any external direction, autonomously self-healing in milliseconds with crystallographic precision. Kelvin probe force microscopy, birefringence experiments, and atomic-resolution structural studies reveal that these noncentrosymmetric crystals, with a combination of hydrogen bonds and dispersive interactions, develop large stress-induced opposite electrical charges on fracture surfaces, prompting an electrostatically driven precise recombination of the pieces via diffusionless self-healing.

Bhunia, Surojit↗
DOE OSTI2022

Electric Field Measurements at the Surface of a Piezoelectric Transformer for Plasma Jet Formation using the Plasma Research Facility at Sandia National Laboratory (Final Report)

The overall goal of this research is to understand how low-temperature non-equilibrium plasmas form directly off the surface of piezoelectric crystals. Specifically, this project aims to temporally and spatially resolve how the electric field evolves on and near the surface of a piezoelectric transformer (PT) at conditions that produce an atmospheric-pressure air plasma jet emanating from the corner of the PT. In this work, we used the Plasma Research Facility (PRF) at Sandia National Laboratory to conduct temporally- and spatially-resolved electric field induced second harmonic (E-FISH) measurements of the electric field at and near the surface of a piezoelectric transformer, providing a fundamental understanding of how piezoelectric crystals can be used for plasma generation. We carried out two Objectives: Objective 1 – The first objective was to measure the temporal and spatial evolution of the electric field along the surfaces approaching the corner of a rectangular PT just below conditions that lead to plasma jet formation. Such a measurement can be used to explain when and where the electric field peaks, leading to plasma formation; Objective 2 – The second objective was to measure the temporal and spatial evolution of the electric field along the surfaces approaching the corner of a rectangular PT just at conditions of plasma jet formation. This, in principle, gives a more accurate determination of how the electric field leads to plasma formation but is more difficult due to the relatively stochastic plasma jet behavior of a PT. This work was complemented by an award from the Sandia PRF, and we worked with Dr. Edward Barnat at the Sandia PRF to carry out these objectives.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Diffused morphotropic phase boundary in relaxor-PbTiO 3 crystals: High piezoelectricity with improved thermal stability

Solid solution ferroelectrics are the most widely used piezoelectric material for numerous electromechanical applications, including sensors, actuators, and transducers. A milestone in ferroelectric research is the discovery of the morphotropic phase boundary that was first reported in Pb(Zr x Ti 1–x )O 3 , which has been extensively solicited to improve the performance of various solid solution ferroelectrics, including those having the highest piezoelectricity known today. However, due to the inherent correlation between phase transition and thermodynamic imbalance, the efforts of building the phase boundary encounter the challenge that high performance materials are generally accompanied by property instability. In this paper, we report a comprehensive study on the crystalline symmetry and polar nano-regions in relaxor-PbTiO 3 crystals by synchrotron measurements and property characterizations. In contrast to the common belief that the morphotropic phase boundary is a narrow composition region, the morphotropic phase boundary in ternary Pb(In 1/2 Nb 1/2 )O 3 -Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 is demonstrated as an extensive region covering at least 9% of the PbTiO 3 content. Such a diffused morphotropic phase boundary is associated with the intensive interaction of polar nano-regions, leading to high piezoelectricity (>1500 pC/N) with greatly improved thermal stability, where the piezoelectric variation is ~90% over the temperature range of 273–373 K, which is about a factor of 3 lower compared to its binary counterpart Pb(Mg 1/3 Nb 2/3 )O 3 -PbTiO 3 . This work sheds light on the fundamental understanding of nanoscale inhomogeneity and macroscopic symmetry in relaxor-PbTiO 3 , and successfully interlinks the structure and properties in complex solid solutions. The existence of a diffused morphotropic phase boundary is also expected to benefit other ferroic systems beyond ferroelectrics, such as ferromagnetic and multiferroic materials.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2023

Technology Maturation of Wireless Harsh Environment Sensors For Improved Condition Based Monitoring Of Coal Fired Power Generation

The overall goal of this project was to demonstrate and develop the usage of high-temperature (HT) harsh-environment (HE) wireless surface acoustic wave resonator (SAWR) sensor technology to promote reliable maintenance through condition-based maintenance (CBM) for field applications in harsh service conditions associated with power plant environments. The project aimed to advance the HT HE wireless SAWR sensor technology from TRL 5 to TRL 7. In addition to HT HE wireless temperature sensing, efforts were dedicated during this project to investigate, develop and increase the TRL from 3 to 5 for the following technologies: (a) HT HE strain sensors to address additional CBM monitoring needs, such as boiler tube mechanical / thermal stresses, which can provide early indications for boiler tube cracking and failure; and (b) HT aluminum nitride (AlN) and scandium aluminum nitride (ScAlN) based piezoelectric thin film fabrication and implementation of SAW sensors, with the goal of releasing the need to use single crystal piezoelectric materials for SAWRs and thus broaden possible technology applications to non-planar and harder to modify surfaces. To achieve the goals mentioned above, UMaine and its partner, Environetix Technologies Corporation, established partnerships with the following power plants: Longview Power (Maidsville, WV), a coal-fired power plant; Penobscot Energy Recovery Corp (PERC, Orrington, ME), a waste-to-energy power plant; and the UMaine Steam Plant (Orono, ME), an oil / natural gas power plant. To realize wireless HT HE SAWR sensor systems in these harsh service conditions, the University of Maine research team worked with Environetix and these power plants to define, design, fabricate, test and validate a mature prototype wireless temperature SAWR sensor system for boiler tube applications within the HT HE of the reheater pass damper chamber to directly and wirelessly monitor the temperature at eighteen independent boiler tube locations. The system included three levels, or “tiers”, of wireless communication to enable remote monitoring: Tier 1, the wireless link in the reheater pass damper chamber directly accessing the sensors on the boilers; Tier 2, the wireless local area network link, transmitting processed sensor information within the power plant to the Tier 3, a commercial wireless signal carrier company for secure remote data monitoring outside of the power plant. Regarding the wireless sensor system installed at Longview Power, temperature information from the boilers was continuously transmitted from the Longview boilers at Maidsville, WV, to Environetix headquarters, Orono, ME, over a 34 month period, when the system was finally decommissioned. Strain sensors and piezoelectric ScAlN thin film sensors were successfully installed on the exhaust duct at the UMaine Steam Power plant. The advances in wireless strain sensors and thin film piezoelectric film fabrication and testing were performed mostly in UMaine laboratories and field tested at the UMaine Steam Plant, due to its close proximity to UMaine/Environetix, access to the plant facility, and due to difficulties in accessing the other power plants during the COVID shut-down period. The project accomplished the TRL level increase of the targeted CBM technologies through the successful fabrication, installation, test, and validation of dedicated and commercial wireless sensor systems, utilizing the three different power plants. The outcomes of this project, including the wireless sensor data capability, are expected to yield an advance for CBM in harsh power plant environments. The reduction of maintenance costs, improved safety during plant operation, and increased power plant efficiency will lead to increased revenues (i.e., fewer forced outages) due to better process monitoring enabled by the wireless HT HE SAWR temperature sensor technology.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2024

Final Report on Characterization of Irradiated Sensors and Coupling Adhesive Bonds

This report summarizes characterization via scanning/transmission electron microscopy of the microstructures of the unirradiated and irradiated piezoelectric ultrasonic sensor/aluminum substrate assemblies using four commercially available inorganic coupling adhesives to bond two types of piezoelectric crystals to the substrates. The sample assemblies were irradiated in the PULSTAR reactor at NC State University and ultrasonic data was collected in-situ. ORNL LAMDA Laboratory capabilities were utilized to perform pre- and post-irradiation examination of the sensor assemblies. This document summarizes the PIE performed at the ORNL LAMDA laboratory. The results of the PIE described in this report are consistent with the ultrasonic data collected during irradiation – in particular, high temperature epoxy adhesive seemed to provide the best coupling as compared to the refractory ceramic adhesives. It was determined that the quality of the sensor-adhesive-substrates governed the ultrasonic performance of the sensors. It was also apparent that irradiation did not significantly affect bond quality, which is also supported by the ultrasonic data collected during irradiation. A more comprehensive DOE NSUF Final Report including details of materials selection, sample fabrication, initial ultrasonic testing, irradiation and in-situ ultrasonic testing, positron annihilation lifetime spectroscopy and doppler broadening spectroscopy performed at EPRI and NC State University will be published at the conclusion of the project.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials and methods for the preparation of nanocomposites

Disclosed herein is an isolable colloidal particle comprising a nanoparticle and an inorganic capping agent bound to the surface of the nanoparticle, a method for making the same in a biphasic solvent mixture, and the formation of structures and solids from the isolable colloidal particle. The process can yield photovoltaic cells, piezoelectric crystals, thermoelectric layers, optoelectronic layers, light emitting diodes, ferroelectric layers, thin film transistors, floating gate memory devices, phase change layers, and sensor devices.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Flexible piezoelectric and ferroelectric haloimidazole crystals

Provided herein are substituted haloimidazole crystals, the substituted haloimidazole crystal comprising a substituted haloimidazole compound wherein the substituents are selected from the group consisting of hydrogen, an alkyl, and a halogen. The substituted haloimidazole crystals may further comprise second substituted haloimidazole. The substituted haloimidazole crystals may be piezoelectric, ferroelectric, flexible, or any combination thereof. Also provided herein are methods for preparing substituted haloimidazole crystals.

Owczarek, Magdalena↗
DOE OSTI2021

Widespread Negative Longitudinal Piezoelectric Responses in Ferroelectric Crystals with Layered Structures

In this study, we investigate the underlying mechanisms of the universal negative piezoelectricity in low-dimensional layered materials by carrying out first-principles calculations. Two-dimensional layered ferroelectric CuInP 2 S 6 is analyzed in detail as a typical example, but the theory can be applied to any other low-dimensional layered piezoelectrics. Consistent with the theory proposed in [Phys. Rev. Lett. 119, 207601 (2017), the anomalous negative piezoelectricity in CuInP 2 S 6 also results from its negative clamped-ion term, which cannot be compensated by the positive internal-strain part. Here, we focus on a more general rule by proposing that having a negative clamped-ion term should be universal among piezoelectric materials, which is attributed to the “lag of Wannier center” effect. The internal-strain term, which is the change in polarization due to structural relaxation in response to strain, is mostly determined by the spatial structure and chemical bonding of the material. In a low-dimensional layered piezoelectric material such as CuInP 2 S 6 , the internal-strain term is approximately zero. This is because the internal structure of the molecular layers, which are bonded by the weak van der Waals interaction, responds little to the strain. As a result, the magnitude of the dipole, which depends strongly on the dimension and structure of the molecular layer, also has a small response with respect to strain. An equation bridging the internal strain responses in low-dimensional and three-dimensional piezoelectrics is also derived to analytically express this point. This work aims to deepen our understanding about this anomalous piezoelectric effect, especially in low-dimensional layered materials, and provide strategies for discovering materials with novel electromechanical properties.

2-dimensional systems↗
DOE OSTI2026

High-entropy 1D halide perovskite piezoelectrics found by megalibrary synthesis and rapid nonlinear optical screening

Piezoelectric molecular crystals offer excellent compositional and structural tunability and sustainable processability. However, their discovery is slow, primarily due to the serial synthesis and screening processes used. Here, we report an approach that combines massively parallel megalibrary synthesis with scanning second harmonic generation (SHG) microscopy for rapid screening of piezoelectric molecular crystals. Megalibraries consisting of more than 1,000,000 compositionally distinct but positionally encoded TMCM x TMA (1–x) Cd y Pb (1–y) ClzBr (3–z) (TMCM: trimethylchloromethylammonium, TMA: tetramethylammonium; 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, 0 ≤ z ≤ 3) nanocrystals were synthesized. The megalibraries were rapidly screened by SHG microscopy to identify notable noncentrosymmetric structures, which were then tested for piezoelectricity, facilitating discovery of a high-entropy noncentrosymmetric material with a large d 33 (TMCM 0.75 TMA 0.25 Cd 0.75 Pb 0.25 Cl 1.5 Br 1.5 , 42.8 picocoulombs per newton). Furthermore, this approach enabled systematic investigation of the Curie temperature (T C )–composition relationship in the TMCMCdCl z Br (3–z) system, facilitating reverse design of materials with targeted T C . Our work establishes a powerful approach to accelerate the discovery and design of unusual piezoelectrics for next-generation electronics and optics.

Li, Jun [Northwestern University, Evanston, IL (Un↗
DOE OSTI2022

Hard-to-soft transition-enhanced piezoelectricity in poly(vinylidene fluoride) via relaxor-like secondary crystals activated by high-power ultrasonication

We report although high piezoelectric coefficients have recently been observed in poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] random copolymers, they have low Curie temperatures, which makes their piezoelectricity thermally unstable. It has been challenging to achieve high piezoelectric performance from the more thermally stable PVDF homopolymer. In this report, we describe how high-power ultrasonic processing was used to induce a hard-to-soft piezoelectric transition and improve the piezoelectric coefficient d 31 in neat PVDF. After high-power ultrasonication for 20 min, a uniaxially stretched and poled PVDF film exhibited a high d 31 of 50.2 ± 1.7 pm V -1 at room temperature. Upon heating to 65 °C, the d 31 increased to a maximum value of 76.2 ± 1.2 pm V -1 , and the high piezoelectric performance persisted up to 110 °C. The enhanced piezoelectricity was attributed to the relaxor-like secondary crystals in the oriented amorphous fraction, broken off from the primary crystals by ultrasonication, as suggested by differential scanning calorimetry and broadband dielectric spectroscopy studies.

relaxor-like secondary crystals↗
DOE OSTI2022

Orientation-controlled crystallization of γ-glycine films with enhanced piezoelectricity

Glycine, the simplest amino acid, is considered a promising functional biomaterial owing to its excellent biocompatibility and strong out-of-plane piezoelectricity. Practical applications require glycine films to be manufactured with their strong piezoelectric polar $\langle$001$\rangle$ direction aligned with the film thickness. Based on the recently-developed solidification approach of a polyvinyl alcohol (PVA) and glycine aqueous solution, in this work, we demonstrate that the crystal orientation of the as-synthesized film is determined by the orientation of glycine crystal nuclei. By controlling the local nucleation kinetics via surface curvature tuning, here we shifted the nucleation site from the edge to the middle of the liquid film, and thereby aligned the $\langle$001$\rangle$ direction vertically. As a result, the PVA–glycine–PVA sandwich film exhibits the highest average piezoelectric coefficient d 33 of 6.13 ± 1.13 pC N –1 . This work demonstrates a promising kinetic approach to achieve crystallization and property control in a scalable biocrystal manufacturing process.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

2D Electrets of Ultrathin MoO 2 with Apparent Piezoelectricity

Since graphene, a variety of 2D materials have been fabricated in a quest for a tantalizing combination of properties and desired physiochemical behavior. 2D materials that are piezoelectric, i.e., that allow for a facile conversion of electrical energy into mechanical and vice versa, offer applications for sensors, actuators, energy harvesting, stretchable and flexible electronics, and energy storage, among others. Unfortunately, materials must satisfy stringent symmetry requirements to be classified as piezoelectric. Here, 2D ultrathin single-crystal molybdenum oxide (MoO 2 ) flakes that exhibit unexpected piezoelectric-like response are fabricated, as MoO 2 is centrosymmetric and should not exhibit intrinsic piezoelectricity. However, it is demonstrated that the apparent piezoelectricity in 2D MoO 2 emerges from an electret-like behavior induced by the trapping and stabilization of charges around defects in the material. Arguably, the material represents the first 2D electret material and suggests a route to artificially engineer piezoelectricity in 2D crystals. Specifically, it is found that the maximum out-of-plane piezoresponse is 0.56 pm V -1 , which is as strong as that observed in conventional 2D piezoelectric materials. The charges are found to be highly stable at room temperature with a trapping energy barrier of ≈2 eV.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Studying phonon coherence with a quantum sensor

Nanomechanical oscillators offer numerous advantages for quantum technologies. Their integration with superconducting qubits shows promise for hardware-efficient quantum error-correction protocols involving superpositions of mechanical coherent states. Limitations of this approach include mechanical decoherence processes, particularly two-level system (TLS) defects, which have been widely studied using classical fields and detectors. In this manuscript, we use a superconducting qubit as a quantum sensor to perform phonon number-resolved measurements on a piezoelectrically coupled phononic crystal cavity. This enables a high-resolution study of mechanical dissipation and dephasing in coherent states of variable size ($\overline{n}$ ≃ 1 – 10 phonons). We observe nonexponential relaxation and state size-dependent reduction of the dephasing rate, which we attribute to TLS. Using a numerical model, we reproduce the dissipation signatures (and to a lesser extent, the dephasing signatures) via emission into a small ensemble (N = 5) of rapidly dephasing TLS. Our findings comprise a detailed examination of TLS-induced phonon decoherence in the quantum regime.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗