High Pyroelectric Coefficient Research Articles

Harnessing the power of temperature gradient-enhanced pyroelectricity: self-powered temperature/light detection in Ce-doped HfO2 ferroelectric films with downward spontaneous polarization

Ferroelectric materials are ideal for self-powered sensors in Internet of Things (IoT) and high-precision detection systems due to their excellent polarization properties. Compatibility with miniaturization, high-density systems, and complementary metal oxide semiconductor (CMOS) processes is crucial for their widespread adoption. HfO2-based ferroelectric films show potential in self-powered pyroelectric sensors as their thinness enables effective temperature and light detection. However, the disordered ferroelectric domain distribution limits their pyroelectric performance and hampers the development of highly integrated self-powered pyroelectric devices. This report investigates the temperature and light detection capabilities of Ce-doped HfO2 ferroelectric films, which exhibit as-grown spontaneous polarization in the downward direction, making them a promising option for self-powered pyroelectric sensors. The findings provide robust evidence that the introduction of a temperature gradient significantly enhances pyroelectricity. In addition, their applications in the detection of hot/cold wind and breathing have been proved. Notably, the 30 nm thick Ce-doped HfO2 ferroelectric film has a high pyroelectric coefficient of about 894.7 μC·m–2·K–1 and enables high-precision detection of changes in temperature of 0.1 K. This study highlights the potential application of HfO2-based ferroelectric films in self-powered sensors with temperature and light detection capabilities, making them a promising candidate for future IoT-based systems and high-precision detection systems.

Preparation and mechanism of black LiTaO3 wafer with controlled transmission efficiency of light and resistivity by reduction method

Tantalum lithium (LiTaO3) is known as a “universal” material in the field of functional materials. However, due to its high pyroelectric coefficient and transmission efficiency, practical applications are limited. In this study, black LiTaO3 wafer was prepared by a simple reduction process by using a new reductant composed of FeSiAl flaks, C nanoparticles, and Fe-C core–shell nanoparticles. It was found that the as-prepared wafers have tunable light transmission efficiency and resistance. Moreover, it was also found that the annealing temperature of 800 °C is the threshold temperature of the wafer in the reduction process. Furthermore, it was revealed that the underlying blacking mechanism could be attributed to the wafers' generation of TaC and O vacancies during the reduction process. This work presents a simple method to blackening, uncovers a novel mechanism, and provides tunable light and resistivity transmission efficiency of LiTaO3, which may serve as benchmarks for related studies and promote LiTaO3′s practical applicability.

Magnetron-Sputtered Lead Titanate Thin Films for Pyroelectric Applications: Part 2-Electrical Characteristics and Characterization Methods.

Pyroelectric materials are naturally electrically polarized and exhibits a built-in spontaneous polarization in their unit cell structure even in the absence of any externally applied electric field. These materials are regarded as one of the ideal detector elements for infrared applications because they have a fast response time and uniform sensitivity at room temperature across all wavelengths. Crystals of the perovskite lead titanate (PbTiO3) family show pyroelectric characteristics and undergo structural phase transitions. They have a high Curie temperature (the temperature at which the material changes from the ferroelectric (polar) to the paraelectric (nonpolar) phase), high pyroelectric coefficient, high spontaneous polarization, low dielectric constant, and constitute important component materials not only useful for infrared detection, but also with vast applications in electronic, optic, and MEMS devices. However, the preparation of large perfect and pure single crystals PbTiO3 is challenging. Additionally, difficulties arise in the application of such bulk crystals in terms of connection to processing circuits, large size, and high voltages required for their operation. In this part of the review paper, we explain the electrical behavior and characterization techniques commonly utilized to unravel the pyroelectric properties of lead titanate and its derivatives. Further, it explains how the material preparation techniques affect the electrical characteristics of resulting thin films. It also provides an in-depth discussion of the measurement of pyroelectric coefficients using different techniques.

High pyroelectric performance and its dependence on the field‐induced orientation in antiferroelectric PLZST system

AbstractIn antiferroelectrics (AFE), the recovery of AFE phase from field‐induced ferroelectric (FEIN) phase occurs at the depolarization temperature, Td. In this study, we report an exceptionally high pyroelectric coefficient, p ≈ 16.00 × 10−2 C/m2 K at ∼70°C in the AFE composition Pb0.982La0.012(Zr0.60Sn0.30Ti0.10)O3 which lies close to FE‐AFE phase boundary. We closely examine this FEIN‐AFE transformation in virgin and poled samples, during heating, by temperature‐dependent X‐ray diffraction, polarization, strain–electric field hysteresis, dielectric and pyroelectric studies and report, for the first time, the mechanism responsible for this behavior.

Magnetron Sputtered Lead Titanates Thin Films for Pyroelectric Applications: Part 1: Epitaxial Growth, Material Characterization.

Pyroelectric materials, are those materials with the property that in the absence of any externally applied electric field, develop a built-in spontaneous polarization in their unit cell structure. They are regarded as ideal detector elements for infrared applications because they can provide fast response time and uniform sensitivity at room temperature over all wavelengths. Crystals of the perovskite Lead Titanate (PbTiO3) family show pyroelectric characteristics and undergo structural phase transitions. They have a high Curie temperature (the temperature at which the material changes from the ferroelectric (polar) to the paraelectric (nonpolar) phase), high pyroelectric coefficient, high spontaneous polarization, low dielectric constant, and constitute important component materials not only useful for infrared detection, but also with vast applications in electronic, optic, and Micro-electromechanical systems (MEMS) devices. However, the preparation of large perfect, and pure single crystals of PbTiO3 is challenging. Additionally, difficulties arise in the application of such bulk crystals in terms of connection to processing circuits, large size, and high voltages required for their operation. A number of thin film fabrication techniques have been proposed to overcome these inadequacies, among which, magnetron sputtering has demonstrated many potentials. By addressing these aspects, the review article aims to contribute to the understanding of the challenges in the field of pyroelectric materials, highlight potential solutions, and showcase the advancements and potentials of pyroelectric perovskite series including PbZrTiO3 (PZT), PbxCa1-x (PZN-PT), etc. for which PbTiO3 is the end member. The review is presented in two parts. Part 1 focuses on material aspects, including preparation methods using magnetron sputtering and material characterization. We take a tutorial approach to discuss the progress made in epitaxial growth of lead titanate-based ceramics prepared by magnetron sputtering and examine how processing conditions may affect the crystalline quality of the growing film by linking to the properties of the substrate/buffer layer, growth substrate temperature, and the oxygen partial pressure in the gas mixture. Careful control and optimization of these parameters are crucial for achieving high-quality thin films with desired structural and morphological characteristics.

Novel pyroelectric single crystals PIN-PMN-PT and their applications for NDIR gas detectors

Ternary manganese-doped (1−x−y)Pb(In1/2Nb1/2)O3-xPb(Mg1/3Nb2/3)O3-yPbTiO3 (Mn-doped PIN-PMN-PT) single crystals have demonstrated remarkable pyroelectric properties alongside enhanced temperature stability. These attributes hold substantial promise for the advancement of high precision nondispersive IR (NDIR) applications. In this study, Mn-doped 0.21Pb(In1/2Nb1/2)O3-0.49Pb(Mg1/3Nb2/3)O3-0.30PbTiO3 single crystals were introduced and carefully investigated. A compensated structure of pyroelectric IR detector based on Mn-doped PIN-PMN-PT single crystal was designed and fabricated, and a CO2 gas concentration monitoring module was built. Results showed that Mn-doped PIN-PMN-PT single crystals exhibit high pyroelectric coefficient, and better thermal stability than binary (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 system. The compensated pyroelectric IR detectors using Mn-doped PIN-PMN-PT single crystals as element chips showcase a performance that is approximately fourfold higher than that of commercial LiTaO3 pyroelectric detectors. The NDIR CO2 gas sensor module was assembled and exhibited remarkable accuracy along with an impressively low minimum detection concentration. These outcomes underscores its substantial potential for practical utilization in gas monitoring applications.

Molecular Ferroelectric Crystals with Superior Pyroelectricity, Plasticity, and Recyclability.

The pyroelectric effect is used in a wide range of applications such as infrared (IR) detection and thermal energy harvesting, which require the pyroelectric materials to simultaneously have a high pyroelectric coefficient and a low dielectric constant for high figures of merit. However, in conventional proper ferroelectrics, the positive correlation between the pyroelectric coefficient and the dielectric constant imposes an insurmountable challenge in upgrading the figures of merit. Here, we explored superior pyroelectricity in [(CH3)4N][FeCl4] (TMA-FC) and [(CH3)4N][FeCl3Br] (TMA-FCB) molecular ferroelectric plastic crystals, which could decouple this positive correlation due to the nature of improper polarization behavior. Therefore, TMA-FC and TMA-FCB derive a high pyroelectric coefficient and a low dielectric constant simultaneously, yielding record-high figures of merit around room temperature. Furthermore, the favorable plasticity enables ferroelectric crystals to attach surfaces with different shapes for device design and integration. More interestingly, the molecular ferroelectrics could be softened and reshaped at elevated temperatures without decay in pyroelectricity, making them recyclable for cost savings and e-waste reduction. Combined with the facile fabrication process, the findings of this work would open avenues for employing molecular ferroelectric plastic crystals in the manufacture of high-performance pyroelectric devices.

A molecular pyroelectric enabling broadband photo-pyroelectric effect towards self-driven wide spectral photodetection

Broadband spectral photoresponse has shown bright prospects for various optoelectronic devices, while fulfilling high photoactivity beyond the material bandgap is a great challenge. Here, we present a molecular pyroelectric, N-isopropylbenzylaminium trifluoroacetate (N-IBATFA), of which the broadband photo-pyroelectric effects allow for self-driven wide spectral photodetection. As a simple organic binary salt, N-IBATFA possesses a large polarization (~9.5 μC cm−2), high pyroelectric coefficient (~6.9 μC cm−2 K−1) and figures-of-merits (FV = 187.9 × 10−2 cm2 μC−1; FD = 881.5 × 10−5 Pa−0.5) comparable to the state-of-art pyroelectric materials. Particularly, such intriguing attributes endow broadband photo-pyroelectric effect, namely, transient currents covering ultraviolet (UV, 266 nm) to near-infrared (NIR, 1950 nm) spectral regime, which breaks the restriction of its optical absorption and thus allows wide UV-NIR spectral photodetection. Our finding highlights the potential of molecular system as high-performance candidates toward self-powered wide spectral photodetection.

Figures of merit of PLZT ferroelectric ceramics for practical applications

Structural, microstructural and pyroelectric properties were investigated in PZT-based ferroelectric ceramics for a composition close to the morphotropic phase boundary (Zr/Ti = 53/47), as a function of the lanthanum content. The samples were prepared via the conventional solid-state reaction sintering method. Three compositions were synthetized and studied following the PbZr0.53Ti0.47O3 + x mole% La nominal formula, where x = 0.0, 2.5 and 5.0. The structural characterization confirmed the presence of both tetragonal and rhombohedral phases for all the studied compositions, showing a decrease in the tetragonality factor (c/a) with the increase of the lanthanum concentration. The observed decrease in the stability of the ferroelectric phase (in favor of the paraelectric one) have been discussed in light of the solubility of the doping cation into the studied PZT perovskite structure. Microstructural properties revealed low pores concentration micrographs, showing homogeneous microstructures and uniform grain-sizes. The pyroelectric response of the as-prepared PLZT samples was also investigated in a wide temperature interval. The lower lanthanum content composition exhibited the best properties, characterized by a high pyroelectric coefficient and enhanced figures of merit. These characteristics make such a composition a promising material for practical applications.

Highly Sensitive Pyroelectric Detector Using Atomically Thin Nanoscale Silicon Ditelluride

Two-dimensional (2D) materials are increasingly being used as detectors and are gaining popularity due to the advantage of tunability of their electrical and thermal properties. Certain non-centrosymmetric materials exhibit a property known as pyroelectricity, which can be utilized to detect infrared (IR) radiation. On the other hand, the pyroelectric effect can be induced in centrosymmetric materials by making them react to external stimuli that break up their symmetry. Here, we report the pyroelectric behavior of a centrosymmetric 2D SiTe2 by inducing interface polarization in a Schottky junction. For this bulk, SiTe2 was synthesized via induction melting and its 2D counterpart via liquid-phase exfoliation. A pyroelectric photodetector in Au/p-SiTe2/ITO configuration was fabricated. The electrical studies confirm the formation of a Schottky junction. The 2D SiTe2-based pyroelectric detector exhibited a high pyroelectric coefficient of 3.73 mC/m2 K and a good responsivity of 3.9 × 105 Jones. The obtained pyroelectric coefficient using 2D SiTe2 was remarkably superior to that of conventional bulk materials. This enhanced property arises from the combined effect of the two-dimensional nature of the material and the induced interface polarization in the device. We employed density functional theory to support our experimental observations. The performance results suggest that 2D SiTe2 could be a benchmark candidate for ultrafast pyroelectric detectors.

Enhanced pyroelectric properties of BNT-xBNN lead-free ferroelectric ceramics for energy harvesting

Pyroelectric energy harvesting has been explored to obtain high room temperature pyroelectric coefficient (p) along with high depolarization temperature (Td) for the practical applications. However, the problem that Td and p of Bi0.5Na0.5TiO3-based ceramics cannot be increased simultaneously has not been solved. In this work, (1-x)Bi0.5Na0.5TiO3-xBaNi0.5Nb0.5O3 (BNT-xBNN, x = 0, 0.02, 0.03, 0.04 mol) lead-free ceramics were prepared by conventional solid-state reaction method. Introduction of BaNi0.5Nb0.5O3 can facilitate lattice cell expansion and decrease of the O-B-O bond angles, providing more possibilities for the B-site ion to deviate from the equilibrium position, producing micrometer level grain size (3.25–6.15 µm) with good ferroelectric performance (Pr = 42 μC/cm2, Ps = 47 μC/cm2). The permittivity (εr) of pristine samples raises from 439 to 723 when the content of BNN ascends to 0.03 mol. Hence, an enhanced room temperature p of 7.91 × 10−4 C m−2 K−1 with a high Td of about 150 °C has been attained in BNT-xBNN with x = 0.03 mol, which concomitantly generates the energy density of 22.3 μJ/cm3 with 90 MΩ load. Our work contributes to the development of pyroelectric properties for practical applications in energy harvesting.

High pyroelectric response in Pb0.99Nb0.02[(Zr0.57Sn0.43)1−xTix]0.98O3 ceramics

AbstractBoth high pyroelectric coefficient and figure of merits of ferroelectric materials are desirable for infrared detection. In this work, we prepared Pb0.99Nb0.02[(Zr0.57Sn0.43)1−xTix]0.98O3 (0.060 ≤ x ≤ 0.080) ceramics, and the microstructure and electric properties were studied systematically. It is observed that the composition x = 0.07 shows enhanced pyroelectric properties around ambient temperature due to the ferroelectric–antiferroelectric phase transition, with the pyroelectric coefficient p = 6.83 × 10−4 C m−2 K−1 and the figures of merit Fi = 5.04 × 10−10 m V−1, Fv = 7.61 × 10−2 m2 C−1, and Fd = 3.46 × 10−5 Pa−1/2 at room temperature and the highest pyroelectric coefficient of 695.5 × 10−4 C m−2 K−1 and Fi = 1410.46 × 10−10 m V−1, Fv = 1587.39 × 10−2 m2 C−1, and Fd = 1182.94 × 10−5 Pa−1/2 at 36.7°C. These values are superior to other pyroelectric materials. These results indicate that this system is a promising pyroelectric material for the applications of infrared detectors.

Natural day–night temperature variations driving pyrocatalytic wastewater treatment and CO2 reduction based on room-temperature rhombohedral–tetragonal phase transition of lead-free ferroelectric BZT-0.5BCT fibers

Environmental remediation approaches in terms of wastewater treatment and CO2 reduction using environmental energy are highly desirable for an industrialized society. Herein, the pyrocatalytic performance of electrospun lead-free ferroelectric Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (BZT-xBCT, x = 0.2, 0.3, 0.4, 0.5, 0.6) micro-nano fibers is investigated, and BZT-0.5BCT is identified as an efficient pyrocatalyst for water pollutants decomposition driven by rhombohedral–tetragonal (R-T) phase transition. Phase changes can induce high pyroelectric coefficients. In response to 0–60 °C thermal cycles, the decomposition ratio of Rhodamine B (RhB) by BZT-0.5BCT fibers after nine thermal cycles is approximately 70%. Moreover, under outdoor day-night temperature fluctuations, about 76% of RhB and 95% of methylene blue (MB) can be degraded after 10 and 7 days respectively because BZT-0.5BCT has an R-T phase change point of around 30 °C. For Cr(VI) (potassium dichromate) and tetracycline (TE), the fibers also show good pyrocatalytic degradation ability. Due to destruction of bacterial cell membranes by superoxide groups, high levels of antimicrobial activity could also be achieved against Escherichia coli (99.99%) and Staphylococcus aureus (92.83%). Furthermore, the pyrocatalytic reduction of CO2 to acetaldehyde by BZT-0.5BCT can reach approximately 382.47 μmol g−1 after 20 thermal cycles of 0–60 °C. Therefore, such outstanding catalytic performance of pyroelectric BZT-0.5BCT fibers enables pyroelectric catalysis as a potential approach for both all-round wastewater treatment and CO2 reduction.

Effect of Nd-doping on 0.95(K0.6Na0.4)NbO3-0.05(Bi0.5Na0.5)ZrO3 ceramics: Enhanced electrical properties and piezoelectric energy harvesting capability

Present work reports the influence of Nd-dopant on the structural, microstructural and di-/ferro-/piezo-electrical properties of lead-free binary piezoelectric perovskite system 0.95(K0.6Na0.4)NbO3-0.05(Bi0.5Na0.5)ZrO3 (abbreviated as KNN-BNZ). X-ray diffraction confirmed the formation of perovskite phase with coexisting tetragonal and rhombohedral phases for both the samples. The introduction of Nd3+ in KNN-BNZ resulted in reduced average grain size and curie phase transition temperature (from 347 °C to 294 °C at 1 kHz). Nd-doped KNN-BNZ ceramic showed enhanced piezoelectric response (d33 = 382 pC/N), well saturated P-E hysteresis loops (Ec = 15.27 kV/cm and Pr = 24.74 μC/cm2) with excellent fatigue stability and high pyroelectric coefficient (p ∼ 1418.4 μC/m2/oC). Based on the synthesized piezoceramics, piezoelectric energy harvesting devices were further fabricated and the open-circuit piezo-voltage from pure and Nd-doped KNN-BNZ based devices was measured to be 6.2 and 8.6 V, respectively. The obtained results highlight the candidature of Nd-doped KNN-BNZ ceramic for ferroelectric memory and mechanical vibration energy harvesting devices, as a substitute for lead based ferroelectric perovskites.

Enhanced pyroelectric performance in Na0.5Bi0.5TiO3-xNa0.5Bi4.5Ti4O15 lead-free ferroelectric ceramics via composition and microstructure engineering

Lead-free pyroelectric materials with high room-temperature pyroelectric coefficient (p) and depolarization temperature (Td) are in great demand for uncool infrared detectors. However, the state-of-the-art unleaded pyroelectric ceramics are confronted with challenge of increasing room-temperature pyroelectric coefficient at cost of declining depolarization temperature. Herein, we report that high room-temperature p of 5.28 × 10−4C m − 2K−1 with Td of 175 °C can be simultaneously achieved by introducing Na0.5Bi4.5Ti4O15 into Na0.5Bi0.5TiO3 solid solution system. Structure resolution revealed that the diffusing of Na0.5Bi4.5Ti4O15 not only modifies the structures of TiO6 octahedra and wipes the P4bm nanodomains from the long-range ordered R3c phase, resulting in high remnant polarizations and enhanced room-temperature p, but also facilitates the electron transfer in the formation of Ti-O covalent bond and enhances the strength of Ti-O covalent bonds to improve the stability of crystal structure, leading to the enhancement of Td. Combined with enhanced room-temperature pyroelectric coefficient and high depolarization temperature, the Na0.5Bi0.5TiO3-xNa0.5Bi4.5Ti4O15 systems could be a promising lead-free pyroelectrics for uncool infrared detection.

Piezoelectric, ferroelectric and pyroelectric properties of (100 − x)Pb(Mg1/3Nb2/3)O3 − xPbTiO3 ceramics

A series of (100[Formula: see text]Pb(Mg[Formula: see text]Nb[Formula: see text]O[Formula: see text]PbTiO3 (PMN[Formula: see text]PT, [Formula: see text]= 24, 25, 26) ceramics were prepared by solid-state reaction technique using MgNb2O6 precursor. The results of the detailed characterizations reveal that the content of PT has negligible influence on the grain size, and all samples possess the perovskite structure. As the PT content increases, the samples changed from the normal ferroelectric phase to the ergodic relaxor state at room temperature. As a result, PMN–[Formula: see text]PT ceramics are endowed with electro-strain of 0.08% at a relatively low electric field of 2 kV/mm, and effective piezoelectric coefficient of 320 pm/V was obtained. Simultaneously, the PMN–[Formula: see text]PT ceramics have exceptional pyroelectric performance, exhibiting a high pyroelectric coefficient [Formula: see text][Formula: see text]5.5 – 6.3 × 10[Formula: see text] C⋅cm[Formula: see text]⋅K[Formula: see text]. This study demonstrates the great potential of PMN–[Formula: see text]PT for piezoelectric and pyroelectric device applications.

Lead-free (Ba0.88Ca0.12)(Ti0.94Sn0.06)O3 piezoceramics: A comprehensive analysis of the phase evolution and enhancement of electrical properties induced by high energy ball milling

The study reveals that high-energy ball milling can be employed to induce controlled phase evolution in lead-free (Ba0.88Ca0.12)(Ti0.94Sn0.06)O3(BCST) ceramics. These piezoceramics were fabricated through solid-state sintering route using nanopowders produced by high-energy milling over durations varying from 5 to 30 h. Rietveld refinements confirm the co-existence of orthorhombic (O)-tetragonal (T) phases in the ceramics with their relative proportions systematically changing with the milling duration. The milling technique demonstrates its capability of enhancing the Curie temperature (Tc) appreciably –BCST's low Tc being a serious drawback for not making it a strong contender for replacing widely used PZT in piezoelectric industry. Additionally, the study shows the possibility of enhancing the high pyroelectric coefficient value by 260% and electrostrictive response to as high as 0.048 m4C-2 by only mechanical milling without any change in the ceramic composition. These observed values of pyroelectric and electrostrictive responses are much higher than even those of Pb-based materials.

High pyroelectric performance in Pb0.99Nb0.02[(Zr0.57Sn0.43)0.94Ti0.06]0.98O3/Al2O3 composites by design

AbstractHigh pyroelectric performance around human body temperature is essential for ultra‐sensitive infrared detectors of medical systems. Herein, toward human health monitoring, composite ceramics (1‐x)Pb0.99Nb0.02[(Zr0.57Sn0.43)0.94Ti0.06]0.98O3/xAl2O3 (x = 0, 0.1, and 0.2) were designed. A metastable ferroelectric (FE) phase was induced in the anti‐FE matrix by the Al2O3 component‐induced internal stress, and in turn FE‐anti‐FE phase boundary was constructed. The ceramics at x = 0.2 exhibit high pyroelectric coefficient with p = 10.9 × 10−4 C·m−2·K−1 and figures of merit with current responsivity Fi = 6.23 × 10−10 m·V−1, voltage responsivity Fv = 12.71 × 10−2 m2·C−1, and detectivity Fd = 7.03 × 10−5 Pa−1/2 around human body temperature. Moreover, the enhanced pyroelectric coefficients exist in a broad operation temperature range with a large full width at half maximums of 18.5°C and peak value of 29.2 × 10−4 C·m−2·K−1 at 48.2°C. The designed composite ceramic is a promising candidate for infrared thermal imaging technology of noncontact human health monitoring system.

In situ TEM observation on the ferroelectric‐antiferroelectric transition in Pb(Nb,Zr,Sn,Ti)O3/ZnO

AbstractCeramic composites of (1‐x)Pb0.99{Nb0.02[(Zr0.57Sn0.43)0.937Ti0.063]0.98}O3 (PNZST)/xZnO were recently reported to exhibit exceptionally high pyroelectric coefficients near human body temperature due to the ferroelectric‐antiferroelectric transition of the matrix grains. In the present work, a comparative study is conducted on two composites of x = 0.1 and 0.4 with in situ heating transmission electron microscopy (TEM). The results verify the presence of strain field in the PNZST grain adjacent to a ZnO particle and the stabilized ferroelectric phase at room temperature in the composite of x = 0.1. During heating, the ferroelectric matrix grain transforms to the antiferroelectric phase, contributing to the pyroelectric effect. In the composite of x = 0.4, high‐angle annular dark‐field imaging combined with energy‐dispersive X‐ray spectroscopy reveal the existence of both ZnO and Zn2SnO4. The formation of Zn2SnO4 indicates that Sn in the PNZST matrix grain is selectively extracted, and decomposition of the perovskite phase has taken place. The decomposition products in the form of fine particles are observed to facilitate the nucleation of the antiferroelectric phase and restrict the motion of the phase boundary during heating. The larger amount of ZnO and Zn2SnO4 and the decomposition of the PNZST perovskite phase are suggested to be responsible for the much lower pyroelectric coefficient in the x = 0.4 composite.

Growth, Properties and Applications of Bi0.5Na0.5TiO3 Ferroelectric Nanomaterials.

The emerging demands for miniaturization of electronics has driven the research into various nanomaterials. Lead-free Bi0.5Na0.5TiO3 (BNT) ferroelectric nanomaterials have drawn great interest owing to their superiorities of large remanent polarization, high pyroelectric and piezoelectric coefficients, unique photovoltaic performance and excellent dielectric properties. As attractive multifunctional ferroelectrics, BNT nanomaterials are widely utilized in various fields, such as energy harvest, energy storage, catalysis as well as sensing. The growing desire for precisely controlling the properties of BNT nanomaterials has led to significant advancements in material design and preparation approaches. BNT ferroelectric nanomaterials exhibit significant potential in fabrication of electronic devices and degradation of waste water, which pushes forward the advancement of the Internet of things and sustainable human development. This article presents an overview of research progresses of BNT ferroelectric nanomaterials, including growth, properties and applications. In addition, future prospects are discussed.