BaTiO3 Content Research Articles

P(VDF-TrFE)/BaTiO3 nanocomposite Langmuir-Schaefer thin film for piezoelectric nanogenerator

In this study, a piezoelectric nanogenerator (PENG) was fabricated based on nanocomposite thin films comprising piezoelectric poly(vinylidenefluoride-co-trifluoroethylene) (P(VDF-TrFE)) as a matrix and BaTiO3 (BTO) nanoparticles (NPs) as a nanofiller. The Langmuir-Schaefer (LS) technique was employed to prepare the films. A mixed solution of the polymer and ceramic NPs was spread on the surface of water subphase at a predetermined surface pressure, and thin films were then prepared by transferring the spread monolayer onto indium tin oxide-coated polyethylene terephthalate (ITO-PET) substrate multiple times at a constant surface pressure. Microstructure, crystallinity, β-phase content, dielectric constant, and piezoelectric coefficient (d33) of the thin films were measured with SEM, XRD, FT-IR, LCR meter, and Quasi-static meter, respectively. Six different PENG devices with different BTO contents were fabricated by arranging the thin film-coated substrates in sandwich structure, and they were subject to measurements of piezoelectric characteristics such as open-circuit output voltage (VOC) and short-circuit current (ISC). As results, it was found that the PENG with 4 wt% BTO with ten layers of monolayer deposited at the surface pressure of 15 mN/m yielded the highest VOC of 71.4 V, which was higher than pristine polymer LS film’s 66.2 V at the same conditions, and power density of 35.7 μW/cm2 at 2.5 Hz bending-releasing frequency. This optimum piezoelectric performance was explained in terms of the highest crystallinity, β-phase content, and dielectric properties at the specific BTO content. The optimum PENG coupled with a capacitor and several light emitting demonstrated that it is possibly used to supply power with large energy storage capability of 470 µJ with a 1 µF capacitor for 3 min. This PENG of improved performance is promising as a supply power for a self-powered microelectronics because it has additional advantages of facile fabrication and coating a large area.

Current Achievements in Flexible Piezoelectric Nanogenerators Based on Barium Titanate

Harvesting ambient mechanical energy at the nanometric scale holds great promise for powering small electronics and achieving self-powered electronic devices. The current review is focused on kinetic energy harvesters, particularly on flexible piezoelectric nanogenerators (p-NGs) based on barium titanate (BaTiO3) nanomaterials. p-NGs based on nanotubes, nanowires, nanofibres, nanoplatelets, nanocubes or nanoparticles of BaTiO3 fabricated in vertical or lateral orientation, as well as mixed composite structures, are overviewed here. The achievable power output level is shown to depend on the fabrication method, processing parameters and potential application conditions. Therefore, the most widely studied aspects, such as influence of geometry/orientation, BaTiO3 content, poling process and other factors in the output performance of p-NGs, are discussed. The current standing of BaTiO3-based p-NGs as possible candidates for various applications is summarized, and the issues that need to be addressed for realization of practical piezoelectric energy harvesting devices are discussed.

Morphological, structural, optical, broadband frequency range dielectric and electrical properties of PVDF/PMMA/BaTiO3 nanocomposites for futuristic microelectronic and optoelectronic technologies

Polymer blend nanocomposite (PBNC) films consisted of fluoropolymer poly(vinylidene fluoride) (PVDF) and plexiglass polymer poly(methyl methacrylate) (PMMA) blend host matrix (fixed composition blend of PVDF/PMMA = 80/20 wt/wt%) with barium titanate (BaTiO3) ceramic nanofiller of varying concentrations (x = 0, 2.5, 5, 10, and 15 wt%) were prepared via a state-of-the-art solution-cast method. Scanning electron microscope (SEM) images evidenced high homogeneity of these PBNC films and a huge alteration in the spherulite morphology of the PVDF with the increase in dispersed BaTiO3 concentration in the polymer blend matrix. The X-ray diffraction (XRD) patterns identified the presence of electro-active polar β- and γ-phases of the PVDF crystallites in all the composite materials which are supported by the results of Fourier transform infrared (FTIR) spectra. The differential scanning calorimeter (DSC) thermograms explained the high melting temperature of these overlapped PVDF polymorphs and the degree of crystallinity altered anomalously with the variation of nanofiller concentration. The absorbance of ultraviolet-visible (UV-Vis) radiations enhanced while the direct energy band gap of the 80PVDF/20PMMA blend matrix and also the semiconducting BaTiO3 was found to decrease with the increased concentration of nanomaterial in the host polymer matrix. The ambient temperature broadband dielectric spectra covering the frequency range from 20 Hz to 1 GHz explain that the real part of complex dielectric permittivity reduced with a huge dispersion at higher radio frequencies where the dielectric loss tangent and electric modulus spectra exhibited an intense chain segmental relaxation process. The electrical conductivity of these PBNC films increased with frequency augmented and illustrated a small variation for different concentration composites. The experimental results demonstrated that these PVDF/PMMA/BaTiO3 films could be potential candidates for frequency tunable nanodielectric, electromagnetic interference shielders, a flexible dielectric substrate, thermal insulators, and bandgap regulated materials for futuristic microelectronic, capacitive energy storage, and optoelectronic technologies.

An insight into the temperature-dependent dielectric dispersion and conduction mechanisms in BaTiO3 modified bismuth borate glass-ceramic system

Dielectric characteristics of BaTiO3-modified bismuth borate glass-ceramics have been analyzed at temperatures ranging from 623 to 703 K and a frequency range of 1 Hz–1 MHz. Dielectric permittivity and tan δ have been found to increase with the temperature and BaTiO3 (BT) content. The sharp and intense peak in Z” signifies the presence of grain boundary contributions. R-C and R-CPE models have been employed to analyze the experimentally obtained impedance data of glass-ceramic samples. A theoretical non-exponential Kohlrausch-Williams-Watts (KWW) function has been used to fit experimental data of the imaginary part of the electric modulus. The values of activation energy obtained from impedance and electric modulus are in close agreement with each other and also increase with an increase in BaTiO3. Stretched coefficient (β) is found to be temperature and composition-dependent. The obtained values of β are less than 1, suggesting the nature of relaxation in the samples to be of purely non-Debye type.

Effect of Particle Functionalization on Structural and Dielectric Properties of Flexible TPU/BaTiO3/MWCNTs Composite Films

AbstractFlexible, low‐cost thermoplastic polyurethane (TPU) composite films with functionalized BaTiO3 (BT) and multiwall carbon nanotubes (MWCNTs) are prepared by solution casting and tested as dielectric materials. Different volume content loadings of BT filler (between 10 and 80 vol%) and 0.12 vol% of MWCNTs are applied. The effects of particle functionalization and BT content on the structural, mechanical, and energy storage properties are studied by Fourier infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), as well as puncture and dielectric measurements. It is found that the particle functionalization and BT content significantly affect the hydrogen bonding within the polymer matrix, and have a huge impact on the mechanical and dielectric properties. The optimal concentration (30 vol% of functionalized BT and 0.12 vol% of functionalized MWCNTs) giving the highest dielectric constant of 30.28 and dielectric breakdown strength of 42 kV mm−1 is determined.

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In solid solutions of Na1/2Bi1/2TiO3-xBaTiO3, the question of the relationship between the concentration of BaTiO3(x) and the presence of relaxor properties, as well as at what value of x these properties disappear, was studied. For this purpose, dielectric measurements of polarized and unpolarized compounds were carried out in a wide range of concentrations x 0.05<x<0.45. Ceramic and monocrystalline samples were studied. It was found that relaxation properties exist in the studied concentration range x and the normal ferroelectric state cannot be achieved. This contradicts a number of literature data in which relaxor properties disappear already at x=0.18. It is suggested that different values of x at which relaxor properties are lost may be associated with different sizes and numbers of polar nanoblasts in the cubic ergodic phase resulting from the synthesis of ceramics due to different sintering temperatures and sample densities. It is concluded that the value of x, at which the relaxor properties disappear, is not constant for all NBT-xBT compounds and may vary depending on the synthesis conditions

Composition dependence of structural and piezoelectric properties in Bi(Mg0.5Ti0.5)O3-modified BaTiO3-BiFeO3 ceramics

The chemical composition dependence of the Bi(Mg0.5Ti0.5)O3 (BMT)-modified BaTiO3 (BT)-BiFeO3 (BF) ceramics fabricated by a solid-state synthesis was studied. The effects of BT/BF ratios and BMT concentration on the crystal structure, piezoelectric, and ferroelectric properties were investigated. The crystal structure study carried out under the synchrotron radiation X-ray diffraction revealed a change from rhombohedral structure to the pseudo-cubic structure when the BT contents were increased. A significant change in crystal structure and piezoelectric characteristics was confirmed by varying the BT/BF ratios. In contrast, the crystal symmetry remained unaffected by varying the BMT concentration, while tailoring of the piezoelectric and ferroelectric properties was revealed. Based on the analysis of the structural characteristics and overall electrical properties, the ceramics with modification of the BMT content along with BT/BF ratios could be applied as candidate materials for various practical applications.

Enhancement of Thermoelectric Performance in Bi0.5Sb1.5Te3 Particulate Composites Including Ferroelectric BaTiO3 Nanodots

An increasing number of studies have reported producing composite structures by combining thermoelectric and functional materials. However, combining energy filtering and ferroelectric polarization to enhance the dimensionless figure of merit thermoelectric ZT remains elusive. Here we report a composite that contains nanostructured BaTiO3 embedded in a Bi0.5Sb1.5Te3 matrix. We show that ferroelectric BaTiO3 particles are evenly composited with Bi0.5Sb1.5Te3 grains reducing the concentration of free charge carriers with increasing BaTiO3 content. Additionally, as a result of the energy-filtering effect and ferroelectric polarization, the Seebeck coefficient was improved by ∼10% with a ∼10% improvement in power factors. The BaTiO3 phase can effectively scatters phonons reducing lattice thermal conductivity κl (0.5 W m-1 K-1) and increasing ZT to 1.31 at 363 K in Bi0.5Sb1.5Te3 composites with 2 vol % BaTiO3 content giving an improvement of ∼25% over pure Bi0.5Sb1.5Te3. Our work indicates that the introduction of ferroelectric nanoparticles is an effective method for optimizing the ZT of Bi0.5Sb1.5Te3-based thermoelectric materials.

Contrasting phenomena of quenching-induced piezoelectric performance in (0.4Na1/2Bi1/2TiO3-0.6BiFeO3)-xBaTiO3 ferroelectrics and relaxors

Na1/2Bi1/2TiO3 (NBT)-based materials are promising lead-free alternatives due to their large electrostrain and stable mechanical quality factor. Nonetheless, the relatively low depolarization temperature (Td) impairs its practical application. Recently, quenching from sintering temperature was adopted to increase Td of NBT-based ceramics. However, the origin of the quenching-induced increase in Td is still debated. In this study, quenching effects in (1-x)(0.4Na1/2Bi1/2TiO3-0.6BiFeO3)-xBaTiO3 ceramics are investigated. With increasing BaTiO3 content, this system transforms from ferroelectric to relaxor state at room temperature, with a criticality at x = 0.07, which exhibits R3c and P4bm coexisted phases. Ferroelectric and relaxor compositions exhibit different responses upon quenching. Upon quenching the ferroelectrics, Td increases from 420 to 580 °C for x = 0.04, but d33 is majorly unaltered. However, upon quenching the relaxors, Td increases marginally, while d33 increases from 62 to 97 pC/N. The correlation between the structural evolution and electrical responses upon quenching ferroelectric and relaxor compositions is explored.

A magnetostrictive BaTiO3-Fe-Ga & PDMS magnetic field sensor: Research on magnetic detection performance

Pizoelectric flexible magnetic field sensors have recently attracted much attention due to their high sensitivity and fast response time. A clear sensing mechanism will effectively improve the performance of such sensors. Here, we report a BaTiO3-Fe-Ga & PDMS flexible magnetic sensor. The magnetostrictive and magnetic field detection performance of the sensor is simulated by the finite element software. The simulated results show that magnetic field detection can be achieved through magnetostrictive and piezoelectric effects. The flexible magnetic sensor is prepared and tested based on the simulation results. The distribution of the material in the composite film is demonstrated by SEM and EDS. The results show that the sensor with the BaTiO3 concentration of 20% has the best performance and the sensitivity of 3.4 V/T.

Impact of Multi-Walled CNT Incorporation on Dielectric Properties of PVDF-BaTiO3 Nanocomposites and Their Energy Harvesting Possibilities

The current study investigated the fabrication of multi-walled carbon nanotubes (MWCNTs) adhering to Barium titanate (BaTiO3) nanoparticles and poly(vinylidene fluoride) (PVDF) nanocomposites, as well as the impact of MWCNT on the PVDF-BaTiO3 matrix in terms of dielectric constant and dielectric loss with a view to develop a high performance piezoelectric energy harvester in future. The capacity and potential of as-prepared nanocomposite films for the fabrication of high-performance flexible piezoelectric nanogenerator (PNG) were also investigated in this work. In particular, five distinct types of nanocomposites and films were synthesized: PB (bare PVDF–BaTiO3), PBC-1 (PVDF–BaTiO3-0.1 wt% CNT), PBC-2 (PVDF–BaTiO3-0.3 wt% CNT), PBC-3 (PVDF–BaTiO3-0.5 wt% CNT), and PBC-4 (PVDF–BaTiO3-1 wt% CNT). The dielectric constant and dielectric loss increased as MWCNT concentration increased. Sample PBC-3 had the optimum dielectric characteristics of all the as-prepared samples, with the maximum output voltage and current of 4.4 V and 0.66 μA, respectively, with an applied force of ~2N. Fine-tuning the BaTiO3 content and thickness of the PNGs is likely to increase the harvester’s performance even more. It is anticipated that the work would make it easier to fabricate high-performance piezoelectric films and would be a suitable choice for creating high-performance PNG.

Dielectric properties of oligomeric diisocyanate based composites with barium titanate

A series of composites is synthesized on the basis of oligomeric diisocyanate with different contents of ferroelectric filler barium titanate (BaTiO3). The dielectric performances of the obtained composites are found to follow extreme dependences on the filler content with a sharp minimum of the dielectric permittivity and maximum of the dielectric loss tangent at BaTiO3 content 30 vol.%. The characterization of the composite layers by confocal microscopy revealed that the observed dependences of their dielectric properties upon the composition are determined by structural changes of the composites, including percolation, formation of a single infinite cluster and structures of matrix-island and chain types at certain critical concentrations. Keywords: composites, coatings, diisocyanate, barium titanate, dielectric permittivity, dielectric loss, electrochromatography, supercapacitors.

Effect of thermal annealing on dielectric property and thermal conductivity of Si3N4–BaTiO3 composite ceramics

Si3N4–BaTiO3 composite ceramics were prepared by hot pressing sintering. The effects of the amount of BaTiO3 and annealing process on the microstructure, phase composition, dielectric properties and thermal conductivity of Si3N4 composite ceramics were studied. With the increase of BaTiO3 content, the density and the dielectric performance of the Si3N4-based composite ceramics are improved, while the thermal conductivity is reduced. The annealing treatment can not only inhibit the growth of β-Si3N4, refine the grain, reduce the content of intercrystalline glass phase and porosity, but also promote the precipitation of hexagonal barium titanate, all of which are beneficial to increase the dielectric constant and decrease the dielectric loss, but will slightly reduce the thermal conductivity of Si3N4–BaTiO3 composite ceramic. The sample A2BT15 with 15% BaTiO3 sintered at 1750 °C for 2 h and annealed at 1300 °C exhibited the maximum dielectric constant (ε = 10.57), the minimum dielectric loss (tanδ = 9×10-4), a high relative density (98.8%) and an acceptable thermal conductivity (14.5 W·m-1·K-1). Therefore, the selection of appropriate BaTiO3 content and annealing process can regulate the dielectric property, thermal performance and mechanical property of Si3N4–BaTiO3 composite ceramics in a certain range.

Temperature dependent electrical transport behavior of (100-x)Bi2O3-x(BaTiO3) glass system

Impedance measurements were performed as a function of temperature (RT to 700 K) in the frequency range (1 Hz-1MHz) on fabricated Bismuth Barium Titanate glass samples. Dielectric permittivity is found to be increased on increasing both the temperature and BaTiO3 (BT) content in highly polarizable glass matrix of Bi2O3. Experimental data obtained for imaginary part of electric modulus (M″)has been fitted theoretically using non-exponential Kohlrausch-Williams-Watts (KWW) function, however Jonscher's universal power law has been employed to analyze the frequency dependent ac conductivity. The calculated activation energy values for both the samples have been found to be in close agreement with each other and qualify for doubly ionized oxygen vacancies, proposing that the similar kind of charge carriers are involved in the relaxation and conduction mechanisms. Stretched exponent (β) of Modulus and power exponent (n) of ac conductivity, estimated from theoretical fitting of experimental data, have been found to be dependent on temperature and BT (BaTiO3) content. On increasing temperature, an increase in values of (n) suggests that non-overlapping small polaron tunneling (NSPT) model can be easily applied to explain ac conduction and hopping transport mechanisms of the fabricated glass samples.

Effect of BaTiO3 on the Properties of PVC-Based Composite Thick Films.

Flexible PVC/BT (Polyvinyl chloride/Barium Titanate) composite thick films with (0–30%) volume fractions of BaTiO3 were fabricated via the solution casting method. The effects of BaTiO3 filler on the phase, microstructure and dielectric properties of composite films were investigated. The XRD results revealed that BT particles are embedded in the PVC matrix with no chemical reaction taking place between the two phases. It was observed that the glass transition temperature of PVC had increased with the addition of BT. The frequency dispersion in the dielectric constant versus temperature curves indicated the relaxor nature of the composites. The dielectric constant (εr) measured at 40 °C, increased from 7.6 for pure PVC to 16.1 for 30% of BaTiO3 content in PVC polymer matrix. It is suggested that BaTiO3 ceramic powder enhanced the dielectric properties of PVC and may be used as a flexible dielectric material.

Fabrication and properties of reduction-resistant lead-free NaNbO3–BaTiO3 piezoelectric ceramics

Lead-free NaNbO3–BaTiO3 piezoelectric ceramics were fabricated under a low oxygen partial pressure, which enables co-sintering with base metal Ni electrodes. The reducing atmosphere was accurately controlled by adopting a suitable mixture of Ar, H2, and CO2 gases. By adding MnCO3, ZrO2, and Li2CO3, resultant NaNbO3–BaTiO3 ceramics sintered in a reducing atmosphere have high resistivities, maintain high sintering densities, and exhibit piezoelectric constants equivalent or superior to samples prepared in air. The Curie temperatures of the prepared reduction-resistant NaNbO3-BaTiO3 samples depend on the amount of BaTiO3; they can be maintained at approximately 200 °C or higher by setting the BaTiO3 content to 10 mol%. Particularly, 5 mol% MnCO3, 2 mol% ZrO2, and 1 mol% Li2CO3-added (Na0.9Ba0.1)(Nb0.9Ti0.1)O3 ceramics sintered under a low oxygen partial pressure (PO2 = 10–8 atm at 1250 °C) showed a piezoelectric constant (d 33) of 135 pC N−1 and an electromechanical coupling coefficient (k p) of approximately 25%.

A Comparative Study of BaTiO3/PDMS Composite Film and a PVDF Nanofiber Mat for Application to Flexible Pressure Sensors

Intensive research has been conducted to develop flexible piezoelectric pressure sensors, since selfpowering devices are advantageous for wearable electronic applications. Recently, two types of piezoelectric devices, ceramic-PDMS composite film and PVDF nanofiber mats, have drawn attention in the research community. Piezoelectric ceramics such as BaTiO3 (BTO) and PZT exhibit outstanding piezoelectric coefficients, while PDMS provides flexibility. In contrast, a PVDF nanofiber mat simultaneously exhibits piezoelectricity and flexibility. In the present study, a comparative analysis of BTO-PDMS composite film and a PVDF nanofiber mat for application to flexible pressure sensors was carried out. First, step-wise electric poling was conducted on these two types of pressure sensors, after which the open-circuit voltage (Voc) was measured under compressive force. The 1.8 V peak-to-peak Voc was measured in a BTO-PDMS composite with a 30 wt.% BTO content that was poled by 10 kV/mm electric field for 15 min. This peak-to-peak Voc of the BTO-PDMS composite increased further to ~ 4 V when it was poled for 24 hr. Unlike the BTO-PDMS composite films, the maximum Voc (1.1 V) was measured in a PVDF nanofiber mat that did not undergo subsequent electric poling. A BTO-PDMS composite film and a PVDF nanofiber mat were fabricated, and the compressive force and strain-rate dependencies of Voc and the short-circuit current (Isc) were investigated. Overall, the Voc and Isc of the BTO-PDMS composite film exceeded those of the PVDF nanofiber mat in a force range of 1 − 25 N and frequency range of 0.5 − 2.0 Hz. However, the Voc and Isc signals from the PVDF nanofiber mat were more stable than those from the BTO-PDMS composite film due to the longer lifetime of the signals.

Structural, microstructural and dielectric characterizations of (Bi0.5Na0.5)TiO3based lead-free ferroelectric ceramics

(1–[Formula: see text][Formula: see text][Formula: see text]TiO3–[Formula: see text]BaTiO3lead-free ceramics have been obtained from the conventional solid-state reaction sintering method. The structural properties were investigated from X-ray diffraction and Raman spectroscopy techniques. Results revealed well-crystallized ceramic samples with perovskite structure. Microstructural properties, obtained from scanning electron microscopy measurements, have shown high density with very low porosity level. The dielectric response, analyzed as a function of the temperature and several frequencies, showed very broad peaks with a strong frequency dependence of the temperature for the maximum dielectric permittivity for the modified system. Results were analyzed considering the influence of the BaTiO3 content on the studied physical properties.

Obtaining and Characterizing 3D Printable Polymer Based Composites with BaTiO3 Filler

By the extrusion and injection technique, polymer-based composite samples (polypropylene and thermoplastic polyurethane) were obtained with BaTiO3 filler in concentrations between 0 and 35 %. Following the preliminary characterizations performed by coupled thermal analysis techniques, it was found that the composite samples obtained have thermal stability up to a temperature of about 250 oC and can be processed by extrusion at temperatures between 180 and 240oC. Above this temperature, a series of degradation processes take place by successive thermooxidation with the formation of volatile products.The electrical characterization of the composite samples was performed by the dielectric spectroscopy technique, which showed that the A tga dielectric losses increase as the BaTiO3 content of the composite increases. The maximum increase being recorded at 50 Hz (the slope A tga /% BaTiO3 about 0.003 /% BaTiO3). It was also found, that the electrical conductivity (o) of the composite increases with the increase of content in BaTiO3 so that o at 100 kHz for the composite with 35 % BaTiO3 is about 50 times higher than for the reference sample M 0 (without filler).

PA1111/BaTiO3 nanocomposites with surprisingly enhanced piezoelectricity at low filler content via in-situ compositing process

A series of PA1111/BaTiO3 nanocomposites with different BaTiO3 contents are prepared by the in-situ salification-melt polymerization procedure. The morphological, spectroscopic studies and the property characterization are conducted. The results indicate that the proposed in-situ compositing method can effectively disperse BaTiO3 nanoparticles in PA1111 matrix, and the as-prepared nanocomposites exhibit improved dielectric and piezoelectric properties as BaTiO3 content up. For the nanocomposite with 10 wt% BaTiO3, compared with that of neat PA1111, d33 and g33 is increased by 1.6 and 1.4 times, respectively. The nanocomposites prepared by the in-situ procedure present high piezoelectricity enhancement efficiency, which is attributed to the uniform particle dispersion in the matrix endowed by the secondary interaction between the organic and inorganic components. This work not only helps broaden the application field of PA1111, but also provides a facile energy-saving and modifier-free compositing procedure for the preparation of the uniform polymer-based nanocomposites.