Pyroelectric Performance Research Articles

Self-powered triboelectric/pyroelectric multimodal sensors with enhanced performances and decoupled multiple stimuli

Abstract Self-powered multifunctional sensors have been receiving great attention for their potential use in sustainable wearable electronics. In this work, we demonstrate a facile approach for the development of self-powered multimodal pressure-temperature sensors based on an identical ferroelectric copolymer, poly (vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) for the contact pair materials by switching the triboelectric polarity via ferroelectric polarization. This approach enables the identical material-based triboelectric devices with remarkably enhanced triboelectric and pyroelectric output performances. The inversely-polarized P(VDF-TrFE) device exhibits ~106 and ~12 times higher triboelectric and pyroelectric currents, respectively, compared to those of non-polarized devices. Consequently, our triboelectric device provides the highest pressure sensitivity of 40 nA kPa−1 and 1.4 V kPa−1 with a broad pressure detection range (98 Pa–98 kPa) as well as competitive temperature sensitivity of 0.38 nA °C−1 and 0.27 nA °C−1 in cooling and heating states, respectively, compared to previous PVDF-based self-powered sensors. Furthermore, our self-powered sensor can discriminate multiple stimuli including pressure as well as temperature without signal interference. Our sensor can be utilized for the monitoring of weak pulse pressure as well as multimodal finger touch. This work provides a facile fabrication approach to realize triboelectric and pyroelectric multimodal devices with outstanding output performances.

High pyroelectric effect in poly(vinylidene fluoride) composites cooperated with diamond nanoparticles

In this work, the synthetic diamond nanoparticles are used as the non-ferroelectric fillers to obtain high pyroelectric performance in PVDF composite films. The oxygen-containing groups that inherently exist on the surface of the diamond nanoparticles make more content of PVDF transform from the α-phase to the β-phase, contributing to the high pyroelectric coefficient. The 0.4 wt% diamond/PVDF film shows the highest pyroelectric coefficient of 870,000 μC/cm2K, which is 3.5 times higher than the pristine PVDF. As a result, the diamond/PVDF films generate higher pyroelectric current and voltage than the pristine PVDF film.

Realizing a ferroelectric state and high pyroelectric performance in antiferroelectric-oxide composites.

We report a robust room temperature ferroelectric (FE) state in (1 - x)Pb0.99Nb0.02[(Zr0.57Sn0.43)0.933Ti0.067]0.98O3-xZnO ((1 - x)PNZST-xZnO) composites, where PNZST shows a predominant antiferroelectric (AFE) nature due to ZnO-induced internal strain. Upon heating, a FE-AFE transition occurs and generates high pyroelectric performance. The composite with x = 0.1 shows a peak pyroelectric coefficient of p = 2450.7 × 10-4 C m-2 K-1 and figures of merit of current responsivity Fi = 926.9 × 10-10 m V-1, voltage responsivity Fv = 1334.3 × 10-2 m2 C-1, and detectivity Fd = 1194.8 × 10-5 Pa-1/2, which are about two orders of magnitude higher than those of most perovskite pyroelectric oxides. More interestingly, the FE-AFE transition temperature, i.e., the temperature corresponding to peak pyroelectric performance, is tunable in a wide temperature range from 30 °C to 65 °C. This work not only provides a promising material candidate for high performance pyroelectric devices, but also an alternative idea to develop ferroelectric and pyroelectric properties based on antiferroelectric materials.

High pyroelectric performance due to ferroelectric–antiferroelectric transition near room temperature

Pyroelectric materials have a huge market in daily life applications and high pyroelectric performances near room temperature are highly desired.

Achieving single domain in rhombohedral and tetragonal Mn‐doped Pb(In1/2Nb1/2)‐Pb(Mg1/3Nb2/3)‐PbTiO3 crystals for infrared detecting applications

AbstractThe [111]‐oriented rhombohedral Mn‐doped 0.15Pb(In1/2Nb1/2)‐0.55Pb(Mg1/3Nb2/3)O3‐0.30PbTiO3 (Mn:PIMNT(15/55/30)) crystal and the [001]‐oriented tetragonal Mn‐doped 0.29Pb(In1/2Nb1/2)‐0.29Pb(Mg1/3Nb2/3)O3‐0.42PbTiO3 (Mn:PIMNT(29/29/42)) crystal were poled under different conditions. The pyroelectric performance of the two crystals as a function of poling temperature, as well as the relationship with ferroelectric domain configuration and phase structure was investigated systematically. The pyroelectric properties of the two crystals enhance with rising the poling temperature, which can be attributed to the improvement of the single state. And for the rhombohedral Mn:PIMNT(15/55/30) crystal locating near morphotropic phase boundary (MPB), the increase of tetragonal phase induces the deterioration of pyroelectric properties. Due to more residual tetragonal phase, the pyroelectric coefficient of the Mn:PIMNT(15/55/30) crystal poled at 150°C is lower than that poled at 100°C. In general, both the crystals poled above TC achieve nearly single state, exhibiting the best pyroelectric properties with relatively high Curie temperature (TC), where P = 9.71 × 10−4 C m−2 K−1, Fi = 3.88 × 10−10 m V−1, Fv = 0.068 m2 C−1 and Fd = 29.7 × 10−5 Pa−1/2 for the rhombohedral Mn:PIMNT(15/55/30) crystal (TC = 171°C) and P = 6.78 × 10−4 C m−2 K−1, Fi = 2.71 ×10−10 mV−1, Fv = 0.1 m2 C−1, Fd = 23.54 × 10−5 Pa−1/2 for the tetragonal Mn:PIMNT(29/29/42) single crystal (TC = 251°C), meeting the stable operation of infrared detector at relatively high environmental temperatures.

Surface and thickness effect on the ferroelectric, dielectric and pyroelectric properties of Mn-doped Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 single crystals

Ferroelectric, dielectric and pyroelectric properties of Mn-doped Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 (PMN-0.28 PT) single crystals has been investigated with surfaces of different roughness, and thickness in the range of 487–16 μm. The crystals were grown by modified Bridgman method and treated by mechanical lapping and chemical mechanical polishing (CMP) for different thickness and surface. The experimental results indicate that the lapping process deteriorates the ferroelectric, dielectric, and pyroelectric performances by introducing domain reorientation and damage into the surface, which can be substantially reduced by polishing process. The surface state exhibits greater impact on the ferroelectric, dielectric and pyroelectric performances when the sample thickness becomes smaller. By lapping, the 109° and 71° domain reorientation occurs along with the generation of non-ferroelectric damage layer, the surface stress and defects.

Significantly enhanced pyroelectric performance in novel sodium niobate‐based lead‐free ceramics by compositional tuning

AbstractIn this study, (1 − x)NaNbO3–xBa0.6(Bi0.5K0.5)0.4TiO3 (abbreviated as NN‐xBBKT, x = 0.05, 0.10, 0.15, and 0.20) lead‐free pyroelectric ceramics were synthesized by conventional solid‐state reaction method. Moreover, their microstructure, phase structure, dielectric, ferroelectric, piezoelectric, and pyroelectric characteristics were studied systematically. The X‐ray diffraction result showed that the phase structure of NN‐xBBKT ceramics changed from orthorhombic to tetragonal and finally became pseudocubic symmetry. The ferroelectric‐paraelectric phase transition temperature and depolarization temperature shifted to lower temperature with the increase in BBKT content. Furthermore, with increasing BBKT content, piezoelectric coefficient, figures of merit, and pyroelectric coefficient first increased and then decreased. The optimum pyroelectric properties (eg Fd = 0.81 × 10−5 Pa−1/2, Fv = 1.02 × 10−2 m2 C−1, Fi = 1.04 × 10−10 m V−1, and p = 3.11 × 10−8 C cm−2 K−1) were observed in sample composition with x = 0.15. More importantly, the pyroelectric coefficient of ceramic with x = 0.15 also displayed relatively high thermal stability because of high depolarization temperature (~110°C). These parameters demonstrate that the novel Pb‐free NaNbO3‐based ceramics form an important class of pyroelectric material with broad range of application prospect.

Plastic/Ferroelectric Crystals with Easily Switchable Polarization: Low-Voltage Operation, Unprecedentedly High Pyroelectric Performance, and Large Piezoelectric Effect in Polycrystalline Forms.

Molecular ferroelectric crystals have attracted growing interest as potential alternatives to conventional lead-based ceramic ferroelectrics. We have recently discovered that a class of compounds known as plastic crystals can show multiaxial ferroelectricity, which allows ferroelectric performance even in polycrystalline forms. Here, we report new plastic/ferroelectric ionic molecular crystals that exhibit remarkably small coercive electric fields at room temperature. The easily switchable ferroelectric polarization enables low-voltage switching operations and high-frequency performance. Such ferroelectric crystals can be readily processed into bulk polycrystalline forms with desired shapes that are characterized by unprecedentedly high pyroelectric figures of merit and large piezoelectricity. These multifunctional molecular crystals represent highly attractive prospects for device elements with a diverse range of applications, which will significantly boost the development of molecular ferroelectric crystals.

Electrocaloric effect and pyroelectric performance in (K,Na)NbO3‐based lead‐free ceramics

AbstractThe issue of how to achieve an electrocaloric effect (ECE) and pyroelectric effect in a material simultaneously remains to be a challenge for developing practical solid‐state cooling devices and RF‐detectors. Here, we structure a polymorphic phase transition (PPT) region by doping modification in KNN‐based ceramics, which are developed to achieve the ECE. The direct measured ECE and pyroelectric properties are investigated in lead‐free (1‐x)K0.5Na0.5NbO3‐xBi0.5Na0.5ZrO3 (KNN‐xBNZ) ceramics. The adiabatic temperature change (∆T) of 0.22 K at 100°C, 0.14 K at 70°C and 0.16 K at 30°C can be obtained under an electric field of 35 kV cm–1 for x = 0.03, 0.04 and 0.05, respectively. In addition, the temperature dependence of pyroelectric coefficient (p) is established for all compositions via the Byer‐Roundy method. A large p of 454.46 × 10–4 C m–2 K–1 is detected at Curie temperature (TC) in the ceramics with x = 0.03. Achieving electrocaloric effect and pyroelectric performance simultaneously may shed light and provide a feasible design scheme for developing practically useful electrocaloric and pyroelectric materials.

Pyroelectric sensor based on Pb(Mg1/3Nb2/3)1-xTixO3 single crystals for solid state hydrogen storage reactors

The pyroelectric effect is commonly used to construct infrared radiation detectors. To pay attention to the possibility of using this phenomenon in materials based on relaxor-ferroelectric such as Pb(Mg1/3Nb2/3)1-xTixO3 (lead titanium-lead magnesium niobate), single crystals from solid solution were grown using modified Bridgman method with x taken three different range (x = 0.25, 0.33 and 0.40).In this work the operation principles for pyroelectric sensor and their properties are presented, with a brief review on the temperature stability of the Pb(Mg1/3Nb2/3)O3–xPbTiO3 (PMN–xPT) single crystals. It was shown that the pyroelectric and dielectric properties are strongly dependent on composition (PT content), as well as the temperature variation. The investigations have revealed that the best choice for pyroelectric performances is <111>oriented PMN–0.25 PT, although, the PMN–0.33 PT and PMN–0.40 PT owns much better temperature stability, and higher Curie temperature Tc.The PMN–xPT single crystals showed promising pyroelectric performances, they can be used as thermal sensors and may be associated with temperature management systems to improve the performance of solid state hydrogen reactors.

Pyroelectric response in the Langmuir–Blodgett fabricated artificial polymer multilayers

Ferroelectric poly(vinylidenefluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer, poly(vinylidenefluoride-trifluoroethylene-chlorofloroethlene) [P(VDF-TrFE-CFE)] terpolymer and P(VDF-TrFE)/P(VDF-TrFE-CFE) multilayers were fabricated by Langmuir–Blodgett (LB) technique. The microstructure, ferroelectric and pyroelectric properties of these films were investigated. In [Formula: see text] multilayer, an enhancement of pyroelectric performance was observed compared with [Formula: see text] multilayer and P(VDF-TrFE-CFE) film. The results indicate that the internal electric field due to polarization mismatch has a dominating contribution from the view of electrostatic coupling.

Pyroelectric performance of [Bi0.48Na0.4032K0.0768]Sr0.04(Ti0.975Nb0.025)O3 ceramics

In the present work, the pyroelectric performance of [Bi0.48Na0.4032K0.0768]Sr0.04(Ti0.975Nb0.025)O3 (BNT-2.5Nb) ceramics is investigated. At room temperature, the value of pyroelectric coefficient found as 13.2 × 10−4 C/m2 K which is higher than many lead-free ferroelectric materials. Further, the pyroelectric figures of merit (FOMs) for detectivity (Fd), voltage responsivity (Fv), current responsivity (Fi), and energy harvesting (Fe*) are calculated. BNT-2.5Nb ceramics show pyroelectric open circuit voltage as 0.45 V when it was exposed to temporal temperature gradient. This work result indicates that the Nb-doping in Bi0.5Na0.5TiO3-based composition can be beneficial for lead-free pyroelectric device applications.

More superior pyroelectric performance of synthesized dravite by high-pressure solid-state method

It’s of great significance to explore the synthesis of tourmaline with simple chemical composition to study the mechanism of its pyroelectric properties due to the presence of crystal defects and isomorphous substitution in natural tourmaline. In the present work, dravite is firstly synthesized by high pressure solid-state method at 5-6 GPa and 550-650 °C. X-ray powder diffraction and electron microprobe analysis data indicate that the synthesized sample is the compound of the dravite with the formula of NaMg3Al6Si6B3O27(OH)4 and a small amount of SiO2. Compared with the natural dravite, the pyroelectric coefficient of the synthesized dravite is improved by an order of magnitude due to the great increase of the intrinsic dipole moment in synthesized dravite. The temperature dependent infrared spectra shows that the dipole moment of each ionic group in the synthesized dravite increases with temperature, leading to the raise of the pyroelectric coefficient with the increment of temperature. And in all ionic groups, [SiO4] tetrahedron and [BO3] triangle are the most important ionic groups that caused the pyroelectricity of tourmaline.

Simultaneous large pyroelectric response and high depolarization temperature in sodium bismuth titanate-based perovskites

To support practical infrared detector applications, pyroelectric ceramics should exhibit excellent pyroelectric performances, high depolarization temperatures, and good thermal stabilities. In this study, the pyroelectric properties, depolarization behaviors, and thermal stabilities of tetragonal 0.8Bi0.5Na0.5TiO3–0.2BaTiO3 (0.8BNT–0.2BT) ceramics are studied systematically. The samples exhibit high depolarization temperatures (∼209 °C) and excellent thermal stabilities. More importantly, they display high pyroelectric coefficients (p = 2.42 × 10−8 C cm−2 K−1), as well as high voltage responsivity (Fv = 2.68 × 10−2 m2 C−1) and specific detectivity (Fd = 1.53 × 10−5 Pa−1/2) figures of merit at room temperature and 1 kHz. The overall properties of tetragonal 0.8BNT–0.2BT ceramics indicate their potential for application in infrared detectors.

Diesel Exhaust Emission Soot Coated Pyroelectric Materials for Improved Thermal Energy Harvesting.

Pyroelectric performance is significantly improved using a coating of diesel exhaust soot. Coated pyroelectric sample (lead zirconate titanate) is exposed to a temporal temperature gradient. Under the application of infrared (IR) heating for a given temperature gradient, the maximum open circuit voltage improves more than four times, electric current across a resistance of 10 ohm improves more than six times, and the stored energy in 10 µF capacitor is enhanced by 17 times. These results are important from two aspects: 1) utilization of waste diesel exhaust soot and 2) improving energy harvesting performance of pyroelectric materials.

Polarization investigation of Mn-doped 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 single crystals for infrared detecting application

This work has been carried out to investigate the poling temperature and poling field dependences of pyroelectric and dielectric properties of ⟨111⟩ oriented Mn-doped 0.72Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 single crystals. Poling treatments are implemented at 25 °C, 90 °C, and 120 °C with DC poling electric fields of 1, 2, 3, and 4 times the corresponding coercive field, respectively. The correlation between ferroelectric domain transition and pyroelectric properties is investigated. The optimized pyroelectric and dielectric performances with the highest pyroelectric coefficient p and the lowest dielectric loss tan δ, as well as the optimized figures of merit, are achieved by poling samples at 90 °C in this study, instead of those conventionally poled at nearly Curie temperature (120 °C). Moreover, excellent long-term performances of 90 °C poled Mn-PMN-0.28PT crystals are disclosed over a 30-day range.

Pyroelectric performance of (Ba0.825+xCa0.175-x)(Ti1-xSnx)O3 lead free ceramics

The pyroelectric properties of (Ba0.825+xCa0.175-x)(Ti1-xSnx)O3 ceramics with x = 0.0625, 0.0875 and 0.100 were investigated. Samples were fabricated using solid state reaction route and were exposed to IR lamp periodically to recorded open circuit voltage. Peak value of open circuit voltage was 0.8 V, 0.70 V and 0.53 V for x = 0.0625, 0.0875 and 0.1 samples, respectively. P–E loops were recorded for all the compositions under study. Further pyroelectric coefficient was estimated using P–E loops data. The values of pyroelectric coefficient estimated as 5.70 × 10−4C/m2 K, 5.5 × 10−4C/m2 K and 5 × 10−4C/m2 K for x = 0.0625,0.0875 and 0.1 samples.

Electrocaloric effect and pyroelectric properties in Ce-doped BaCexTi1−xO3 ceramics

BaCexTi1−xO3 (BCT) ceramics at x = 0.025, 0.05, 0.075 and 0.1 were prepared by the traditional solid state reaction route and sintered at 1540 °C for 6 h. The microstructural, dielectric, electrocaloric, and pyroelectric performances of BCT were systematically explored. Hysteresis loops were measured under various temperatures, and the electrocaloric effect (ECE) was calculated for all samples. The results showed that BaCe0.075T0.925O3 had the best ECE which exhibited a large adiabatic temperature change of 0.81 K, an isothermal entropy change of 0.82 JK−1kg−1 and an electrocaloric strength of ∼0.28 Km/MV. Further, the pyroelectric figure of merits (FOMs) were analyzed and the results indicated that BaCe0.1T0.9O3 would be a better candidate for pyroelectric devices which exhibited high pyroelectric coefficient (p) of 7.82 × 10−4Cm−2K−1 and FOM of high detectivity (Fd) of 10.39 μPa−1/2. These results in this work would facilitated the development of the electrocaloric and pyroelectric performance of Ce-doped BaTiO3 ceramics.

Enhanced Pyroelectric Catalysis of BaTiO3 Nanowires for Utilizing Waste Heat in Pollution Treatment.

A novel catalytic effect of pyroelectric materials induced by a change in temperature, namely pyroelectric catalysis, was found to be attractive due to its ability to utilize waste heat in pollution treatment. In this work, the pyroelectric catalytic properties of BaTiO3 (BTO) nanowires synthesized by a template hydrothermal method have been thoroughly investigated. The nanowires with an elongated polar axis show a superior pyroelectric catalytic performance in comparison with the equiaxial nanoparticles. Our numerical simulation results with a finite element method indicate that the enhanced catalytic efficiency of BTO nanowires can be attributed to the higher pyroelectric potential. On the basis of the pyroelectric effect and our experimental results, a pyroelectric catalytic degradation mechanism has been proposed by taking into account the migration of charge carriers and the formation of reaction radicals. This study for enhancing the pyroelectric catalytic activity by using BTO nanowires may provide a facile, promising, and new reusable strategy for the catalytic degradation of organic dye pollutant by means of temperature variation. It is hoped that the present work gives a clear understanding of the mechanism of pyroelectric catalysis.

Pyroelectric performances of 1-3 ferroelectric composites based on barium titanate nanowires/polyvinylidene fluoride

Pyroelectric properties of 1–3 ceramic/polyvinylidene fluoride (PVDF) composites by using barium titanate nanowires (BTnws) and dopamine modified BTnws (DM-BTnws) as inclusions were firstly reported. 0–3 composites based on dopamine modified BT nanoparticles (DM-BTnps)/PVDF were also prepared for comparison. It was found that low contents of DM-BTnws in PVDF are beneficial for achieving high fraction of β-phase content based on the analysis results of X-ray diffraction (XRD), Fourier transform infrared (FTIR) and electric displacement-electric field (D-E) measurements. The enhancement of β-phase content in the DM-BTnws/composited film was believed to originate from strong hydrogen bonds interactions between poly-dopamine and PVDF molecules, which induced phase transition in PVDF from α-phase into β-phase. However, although DM-BTnws improved β-phase content and, accordingly, pyroelectric coefficient of the composites, they deteriorated dielectric performances of PVDF, reducing pyroelectric performances of the composites in terms of voltage and detectivity figures of merit.