Piezoelectric Figures Of Merit Research Articles

Environmental bacteria engineered piezoelectric bio-organic energy harvester towards clinical applications

State-of-the-art biomedical applications including healthcare monitoring, in vivo real-time sensing and disease treatment largely relies on bio-piezoelectric platforms consisting of biocompatibility and piezoelectricity. However, the inability to design a high performance piezoelectric material with biocompatibility is the major challenges towards practical implementation. Here we present the concept and design principles of an biocompatible piezoelectric material with the assistance of environmental (hot spring) bacterial strain. The biological bacterial protein engineered the microstructure of organic polymer poly(vinylidene fluoride) (PVDF) in order to design the porous bio-organic films with increased biocompatibility, piezoelectric phase content and crystallinity. The porous microstructure significantly enhances the piezoelectric coefficient (d33~ −43 pC/N) and piezoelectric figure of merit (FoMp~ 18.8 ×10−12 Pa−1) of the bio-organic film compared with non-porous pure PVDF (d33~ −0.85 pC/N, FoMp~ 8.5 ×10−15 Pa−1). The proof-of-concept of device designing is also studied, that is nanogenerator composed of bio-organic film is capable to generate maximum output power of as high as 640 mW/m2, possesses energy conversion efficiency of 62.5% which is further used for driving several commercial light emitting diodes (LEDs) and charge capacitors. The enhanced piezoelectric performance is attributed via porosity formation and validated through finite element method (FEM) based theoretical simulation. With the good biocompatibility and piezoelectric pressure sensitivity (1.26 VkPa−1 and 0.86 VkPa−1 in the pressure range of 0.01 −1 kPa and 2 −15 kPa respectively), the device was implemented towards clinical applications of real-time healthcare monitoring from subtle pulse pressure waveform detection to vibrotactile information collection. With its natural biocompatibility, easy to prepare formulation and superior energy harvesting performance, the bio-organic film offers attractive prospects towards the development of effective, sustainable and autonomous electromechanical device for next generation self-powered biomedical devices.

Effect of poling direction and porosity on piezoelectric figures of merit: A numerical study

Piezoelectric materials are at front of scientific research when it comes to sensing, actuation and energy harvesting from smart materials and structures. Crucial to such materials is their output power and performance in terms of figure of merit (FOM). In the present paper, we have compared the effect of two approaches, namely, introducing porosity and poling tuning on different figures of merit. Here, two material systems, 0.3BaTiO3-0.7NaNbO3 (BT-NNb) and Pb[ZrxTi1-x]O3 (PZT-5A), have been considered and the effective piezoelectric properties for different porosity levels (upto 25% volume fraction) and at different poling orientations were computed using representative volume element (RVE). It was observed that for BT-NNb the effective properties get optimised at a given poling orientation unlike in PZT-5A. For BT-NNb, without poling tuning, the maximum change in FOM31, FOM33 and FOMh (associated with transverse (d31), longitudinal (d33) and hydrostatic (dh) piezoelectric strain coefficients) was found to be 14.3%, 14.1% and 14.4% for 25% porous (by volume) system. On the other hand, for the same system, at optimum poling orientation all the FOMs were found to be ∼ 1000 times higher than their corresponding initial values. However, in PZT-5A, no optimum poling orientation was observed and thus it was concluded that FOMs can only be improved by introducing porosity in the system.

Piezoelectric properties of PCW-PNN-PZT ceramics sintered at low temperature

ABSTRACTIn this study, in order to develop the composition ceramics for ultrasonic sensor application, Pb0.985Bi0.01(Co1/2W1/2)0.03(Ni1/3Nb2/3)0.09(ZrxTi1-x)0.88O3+0.25wt% CuO (abbreviated as PCW-PNN-PZT) system ceramics were prepared with the variations of x and then their phase microstructure, piezoelectric and dielectric characteristics were investigated with the variations of x. The compositions near the morphotropic phase boundary (MPB) appeared when x = 0.495. Moreover, the PCW-PNN-PZT ceramics could be sintered at low temperature of 920°C by adding sintering aids CuO. At sintering temperature of 920°C and x = 0.495 specimen, the density (ρ), electromechanical coupling factor(kp), dielectric constant (ϵr), mechanical quality (Qm) and piezoelectric constant (d33) piezoelectric figure of merit (d33·g33) indicated the optimal value of 7.94 g/cm3. 0.65, 1959, 356, 486 pC/N, and 15.56 [pm2/N], respectively, suitable for ultrasonic sensor application. The CuO was proved to lower the sintering temperature of piezoelectric ceramics due to the effects of PbO and CuO liquid phase.

PMW-PNN-PZT 세라믹스의 Bismuth 치환에 따른 미세구조 및 압전 특성

In this study, in order to develop the composition ceramics for ultrasonic sensor with high <TEX>$d_{33}*g_{33}$</TEX>, <TEX>$Pb_{1-3x/2}Bix(Mg_{1/2}W_{1/2})_{0.03}(Ni_{1/3}Nb_{2/3})_{0.09}(Zr_{0.5}Ti_{0.5})_{0.88}O_3$</TEX>(PMW-PNN-PZT) system ceramics were prepared using CuO as sintering aids. And then, their microstructure, piezoelectric and dielectric characteristics were systemetically investigated with bismuth substitution. The PMW-PNN-PZT ceramic specimens could be sintered at sintering temperature of <TEX>$940^{\circ}C$</TEX> by adding sintering aids. At x=0.015 specimen, the density, electromechanical coupling factor(<TEX>$k_p$</TEX>), dielectric constant, piezoelectric constant(<TEX>$d_{33}$</TEX>) and piezoelectric figure of merit(<TEX>$d_{33}*g_{33}$</TEX>) indicated the optimal properties of <TEX>$7.90g/cm^3$</TEX>, 0.67, 2,511, 628 pC/N, and <TEX>$17.7pm^2/N$</TEX>, respectively, for duplex ultrasonic sensor application.

Dielectric and piezoelectric properties of low temperature sintering PMW-PNN-PZT ceramics doped with CuO and Bi for duplex ultrasonic sensor

ABSTRACTIn this study, in order to develop the composition ceramics for duplex ultrasonic sensor application, PMW-PNN-PZT system ceramics were prepared using CuO as sintering aids and their phase microstructure, piezoelectric and dielectric characteristics were minutely investigated with the amount of Bi substitution. The PMW-PNN-PZT ceramic specimens could be sintered at sintering temperature of 920°C by adding sintering aids CuO without secondary phase. At 0.5 mol% Bi substituted specimen, the density, electromechanical coupling factor(kp), dielectric constant, mechanical quality factor(Qm), piezoelectric constant(d33) and piezoelectric figure of merit (d33·g33) indicated optimal properties of 7.93 g/cm3, 0.676, 2265, 70, 611 pC/N, 18.64(pm2/N), respectively, for duplex ultrasonic sensor application.

Piezoelectric properties of low temperature sintering PMW-PNN-PZT ceramics for piezoelectric energy harvesting devices

ABSTRACTIn this study, in order to develop low-temperature sintering ceramics for piezoelectric energy harvesting devices, Pb(Mg1/2W1/2)0.03(Ni1/3Nb2/3)0.09(ZryTi1-y)O3 ceramics were synthesized using conventional mixed oxide method. Effect of Zr/Ti ratio on their piezoelectric and dielectric properties was investigated. XRD-diffraction patterns of all the samples showed perovskite phase, and a secondary phasses was observed. As Zr/Ti ratio was increased, the crystal structure of the ceramics gradually moved from tetragonal to rhombohedral phases, and the compositions near the morphotropic phase boundary(MPB) appeared when Zr/Ti ratio was 50/50. However, at the PMW-PNN-PZT (Zr/Ti = 50.5/49.5) composition ceramics sintered at 920°C, density, electromechanical coupling factor(kp), piezoelectric constant(d33), and dielectric constant, piezoelectric figure of merit (d33·g33) indicated the optimum values of 7.75 g/cm3, 0.62, 556pC/N, 2125, and 16.43(pm2/N), respectively, suitable for energy harvesting device application.

Simultaneous optimisation of orientation and constituent volume in piezoelectric composites

Piezoelectric composites are optimised for maximum strain levels by simultaneously accounting for the concentration and orientation of the piezoelectric and polymer constituents. Existing studies in piezoelectric composites are confined to independently identifying either the optimal volume fraction or the orientation of the piezoelectric phase. Four different composite configurations of single-crystal/polycrystal piezoelectric with polymer are analysed. Yet the polarisation orientation is found to play a crucial role in the piezoelectric response of ferroelectrics. The choice of an optimal composite is complicated, and it is impossible to analyse all possible permutations and combinations of the piezoelectric volume fractions, grain orientation distribution parameters (in the case of polycrystalline piezoelectrics plus polymer) or the crystallographic orientation angles (in the case of single-crystal piezoelectrics and polymer) themselves. Optimal design variables which would generate single-/polycrystalline configurations that enhance the macroscopic piezoelectricity of the composite are identified. It is found that juxtaposing a preferentially oriented piezoelectric material with a polymer into a composite would result in enhancement of piezoelectric figures of merit from constituent phases. It is shown that a small fraction of piezoelectric material (\(v_\mathrm{f}=0.14\)) is sufficient to design an optimal piezoelectric composite that can generate piezoelectric strains comparable to that of single-phase material.

SnO&lt;sub&gt;2&lt;/sub&gt;가 첨가된 저온소결 (Na,K,Li)(Nb,Sb,Ta)O&lt;sub&gt;3&lt;/sub&gt;계 세라믹스의 유전 및 압전 특성

In this paper, in order to develop excellent Pb-free composition ceramics for ultrasonic sensor. The -doped ()(abbreviated as NKL-NST) ceramics have been synthesized using the ordinary solid state reaction method. The effect of -doping on their dielectric and piezoelectric properties was investigated. The ceramics doped with 0 wt% have the optimum values of piezoelectric constant(), piezoelectric figure of merit(), planar piezoelectric coupling coefficient() and density : , , . suitable for duplex ultrasonic sensor application.

Structural, dielectric relaxation and piezoelectric characterization of Sr 2+ substituted modified PMS-PZT ceramic

Pyrochlore phase free [Pb 0.94Sr 0.06] [(Mn 1/3Sb 2/3) 0.05(Zr 0.53Ti 0.47) 0.95] O 3 ceramics has been synthesized with pure Perovskite phase by semi-wet route using the columbite precursor method. The field dependences of the dielectric response and the conductivity have been measured in a frequency range from 50 Hz to 1 MHz and in a temperature range from 303 K to 773 K. An analysis of the real and imaginary parts of the dielectric permittivity with frequency has been performed, assuming a distribution of relaxation times. The scaling behavior of the dielectric loss spectra suggests that the distribution of the relaxation times is temperature independent. The SEM photographs of the sintered specimens present the homogenous structures and well-grown grains with a sharp grain boundary. The material exhibits tetragonal structure. When measured at frequency (100 Hz), the polarization shows a strong field dependence. Different piezoelectric figures of merit ( k p, d 33 and Q m) of the material have also been measured obtaining their values as 0.53, 271 pC/N and 1115, respectively, which are even higher than those of pure PZT with morphotropic phase boundary (MPB) composition. Thus the present ceramics have the optimal overall performance and are promising candidates for the various high power piezoelectric applications.

Processing–Property Relations in Grain‐Oriented Lead Metaniobate Ceramics Fabricated by Layered Manufacturing

Highly grain‐oriented lead metaniobate (PbNb2O6; PN) ceramics were prepared by a layered manufacturing (LM) process. This process has enabled us to obtain a net‐shaped piezoelectric ceramic component with grain orientation of f∼89%, and improvement in electromechanical properties. The LM feedstock (filament) includes equiaxed (matrix; 90 vol%) and anisometric PN templates (10 vol%), both dispersed uniformly in a thermoplastic binder. The needle‐like PN templates were synthesized by molten salt synthesis technique, while the equiaxed PN powder was prepared by conventional ceramic processing methods. The processing conditions were studied and optimized to obtain orthorhombic phase fine powder and anisometric templates. Samples were obtained through layer‐by‐layer deposition of the filament through a small diameter (500 μm) nozzle. After binder removal, the PN samples were sintered in a temperature range of 1150°–1300°C for 1 h. SEM observation revealed strong grain orientation perpendicular to the deposition direction. Relative permittivity at the Curie point (Tc: 560°C) was 18 100 and 14 600 for the LM and random polycrystalline samples, respectively. Improved properties in piezoelectric figure of merit by 71%, d33 by 23%, and g33 by 31% were observed in the grain‐oriented samples. Remnant polarization also showed about 80% improvement, increasing from 4.5 to 8.1 μC/cm2 for the grain‐oriented LM samples.

Development of novel polycrystalline materials on the basis of Sn2P2S6 for hydrophone applications

Polycrystalline textures, pressed powder and 0-3 composites on the basis of Sn2P2S6 have been prepared with the aim to identify an optimum polycrystalline form with high piezoelectric figure of merit which would offer the prospect of application in hydrophone devices. 0-3 Sn2P2S6/PVA (poly-vinyl alcohol) composite shows the highest hydrostatic piezoelectric voltage sensitivity (gh=210* 103Vm/N). The electromechanical coupling coefficients kt, kp and piezoelectric coefficient d33 for this composite were found to be 41%, 16% and 60 pC/N respectively. The dielectric properties of the materials studied, in particular the nature of the low frequency dielectric dispersion are discussed.

Investigations on the piezoelectric and structural properties of samarium-doped lead zirconate titanate ceramics

Lead zirconate titanate (PZT) ( Zr/Ti = 65/35 ) ceramics were doped with various atomic percentages of samarium (Sm) and their piezoelectric and structural properties were studied. There is a significant improvement in the piezoelectric figure of merit ( d h g h ) of PZT when SM 3+ is introduced into the A sites. PZT containing 4 at.% Sm shows a figure of merit of about 1400. The structural studies performed on the samples indicate that this composition shows a coexistence of rhombohedral and tetragonal phases.