Sodium Bismuth Titanate Research Articles

Contribution of piezoelectric effect on piezo-phototronic coupling in ferroelectrics: A theory assisted experimental approach on NBT.

A new study explores the distinct roles of spontaneous polarization and piezoelectric polarization in piezo-phototronic coupling. This investigation focuses on differences in photocatalytic and piezo-photocatalytic performance using sodium bismuth titanate, a key ferroelectric material. The research aims to identify which type of polarization has a greater influence on piezo-phototronic effects. A theoretical assessment complements the experimental findings, providing additional insights. This study explores the enhanced piezo-phototronic performance of electrospun nanofibers compared to sol-gel particles under different illumination conditions (11 W UV, 250W UV, and natural sunlight). Electrospun nanofibers exhibited a rate constant (k) improvement of 2.5 to 3.75 times, whereas sol-gel particles showed only 1.3 to 1.4 times higher performance when ultrasonication was added to photocatalysis. Analysis using first-principle methods revealed that nanofibers had an elastic modulus (C33) about 2.15 times lower than sol-gel particles, indicating greater flexibility. The elongation of the lattice along the z axis in the case of nanofibers reduced the covalency in the Bi-O and Ti-O bonds. These structural differences reduced spontaneous polarization and piezoelectric stress coefficients (e31 and e33). Despite having lower piezoelectric stress coefficients, higher flexibility in nanofibers led to a higher piezoelectric strain coefficient, 2.66 and 1.97 times greater than sol-gel particles, respectively. This improved the piezo-phototronic coupling for nanofibers.

Performance of dye-sensitized solar cells of perovskite sodium bismuth titanate layer and studying the effect of Fe-doped on the photovoltaic properties

Performance of dye-sensitized solar cells of perovskite sodium bismuth titanate layer and studying the effect of Fe-doped on the photovoltaic properties

Enhanced Energy Storage Properties of Four-Layer Composite Films via Strategic Macrointerface Modulation.

Dielectric capacitors play a crucial role in the field of energy storage; however, the low discharged energy density (Ue) of existing commercial dielectrics limits their future applications. Currently, further improvement in the Ue of dielectrics is constrained by the challenge of simultaneously achieving high permittivity (εr) and high breakdown electric field strength (Eb). To address this issue, we designed a series of four-layer poly(vinylidene fluoride) (PVDF)-based composite films comprising three functional layers: a sodium bismuth titanate (NBT) plus PVDF composite (NBT&PVDF) layer to achieve high εr values and a pure PVDF layer and a boron nitride (BN) plus PVDF composite (BN&PVDF) layer to achieve high Eb values. This design synergistically enhanced the εr and Eb values of the composite films by exploiting low-loss macrointerface polarization via adjustment of the functional layer stacking order, as supported by simulation analyses. Ultimately, the composite film with a topmost layer of pure PVDF, followed by an NBT&PVDF layer, another pure PVDF layer, and a BN&PVDF layer achieved an enhanced Ue value of 26.42 J·cm-3 and excellent efficiency of 80.03% at an ultrahigh Eb value of 770 MV·m-1. This approach offers an innovative pathway for developing advanced energy storage composite dielectrics via macrointerface manipulation.

Microwave-Assisted Fabrication and Characterization of Carbon Fiber-Sodium Bismuth Titanate Composites

Lead-based piezoelectric materials cause many environmental problems, regardless of their exceptional performance. To overcome this issue, a lead-free piezoelectric composite material was developed by incorporating different percentages of carbon fiber (CF) into the ceramic matrix of Bismuth Sodium Titanate (BNT) by employing the microwave sintering technique. The aim of this study was also to evaluate the impact of microwave sintering on the microstructure and the electrical behavior of the carbon-fiber-reinforced Bi0.5Na0.5TiO3 composite (BNT-CF). A uniform distribution of the CF and increased densification of the BNT-CF was achieved, leading to improved piezoelectric properties. X-ray diffraction (XRD) showed the formation of a phase-pure crystalline perovskite structure consisting of CF and BNT. A Field Emission Scanning electron microscope (FESEM) revealed that utilizing microwave sintering at lower temperatures and shorter dwell times results in a superior densification of the BNT-CF. Raman Spectroscopy confirmed the perovskite structure of the BNT-CF and the presence of a Morphotropic Phase Boundary (MPB). An analysis of nanohardness indicated that the hardness of the BNT-CF increases with the increasing amount of CF. It is also revealed that the electrical conductivity of the BNT-CF at a low frequency is significantly influenced by the amount of CF and the temperature. Moreover, an increase in the carbon fiber concentration resulted in a decrease in dielectric properties. Finally, a lead-free piezoelectric BNT-CF showing dense and uniform microstructure was developed by the microwave sintering process. The promising properties of the BNT-CF make it attractive for many industrial applications.

Enhancement of Microwave Absorption Properties of Crystal‐Engineered Perovskite Oxide Using Cobalt Ferrite

A multiferroic composite that comprises of a non‐ferromagnetic ferroelectric material with a high dielectric constant and a non‐ferroelectric ferromagnetic material with a high magnetostriction is of tremendous interest as microwave absorption material due to its applicability in tunable microwave phase shifters, resonators, filters, absorbers, etc. In the previous work, the solid solution of strontium titanate and sodium bismuth titanate (Sr0.5(Na0.5Bi0.5)0.5TiO3, SNBT50), which is observed to possess a very high dielectric constant at room temperature (Ferroelectrics, Vol 583, 252–263 [2021]), is successfully reported. Thus, in this work, a core–shell magnetoelectric composite is prepared by coating highly ferromagnetic and magnetostrictive cobalt ferrite onto a diamagnetic but strongly ferroelectric SNBT50 to enhance its magnetic properties and to investigate the modification in microwave absorption. Detailed characterization of electric and magnetic parameters in microwave frequency range (1–20 GHz) reports substantial enhancement in the magnetic permeabilities as well as the magnetic loss of the composite system, as opposed to bare SNBT50. This results in improved impedance matching in the system and enhanced microwave absorption, with a minimum reflection loss (RL) of −20.19 dB and an increased effective absorption bandwidth of 4.56 GHz at a mere 2.7 mm absorber length. Consequently, in this investigation, a promising pathway is established for the development of multiferroic composites with favorable magnetoelectric coupling at room temperature that possesses wide absorption bandwidth and suitable RL, making them highly suitable for use in multiferroic‐based microwave components.

KNN composite ceramics with superior pyroelectric performance for self-powered thermal detector

The thermal detector based on pyroelectric effect has attracted widespread attention due to its self-powering and rapid response. Although phase boundary engineered lead-free potassium sodium niobate [K0.5Na0.5NbO3, KNN] based ferroelectrics exhibit promising for pyroelectric sensor application, the high dielectric constants (εr) of these materials significantly constrain their pyroelectric figures of merit (FOMs), owing to the inverse correlation between FOMs and εr. To address this problem, we innovatively introduce perovskite bismuth sodium titanate [Bi0.5Na0.5TiO3, BNT] with low εr and high pyroelectric coefficient as the second phase to construct a KNN/BNT composite. The introduction of BNT can not only remain the high pyroelectric coefficient (p=7.12 × 10−4 C m−2 K−1) of KNN matrix, but also result in superior FOMs (Fv increased by 74 %), outperforming previous KNN-based pyroelectric ceramics. The excellent pyroelectric performance originates from the unique composite microstructure with compositional heterogeneity. That is, both the low εr BNT enriched phase and refined grain size as well as the promoted vibration of Nb–O octahedron contribute to the superior pyroelectric performance. A self-powered thermal detector with great thermal response has been developed, which also exhibits potential for detecting ultraviolet energy and infrared radiation.

Enhancing Energy Storage Performance of 0.85Bi0.5Na0.5TiO3-0.15LaFeO3 Lead-Free Ferroelectric Ceramics via Buried Sintering.

Bismuth sodium titanate (Bi0.5Na0.5TiO3, BNT) ceramics are expected to replace traditional lead-based materials because of their excellent ferroelectric and piezoelectric characteristics, and they are widely used in the industrial, military, and medical fields. However, BNT ceramics have a low breakdown field strength, which leads to unsatisfactory energy storage performance. In this work, 0.85Bi0.5Na0.5TiO3-0.15LaFeO3 ceramics are prepared by the traditional high-temperature solid-phase reaction method, and their energy storage performance is greatly enhanced by improving the process of buried sintering. The results show that the buried sintering method can inhibit the formation of oxygen vacancy, reduce the volatilization of Bi2O3, and greatly improve the breakdown field strength of the ceramics so that the energy storage performance can be significantly enhanced. The breakdown field strength increases from 210 kV/cm to 310 kV/cm, and the energy storage density increases from 1.759 J/cm3 to 4.923 J/cm3. In addition, the energy storage density and energy storage efficiency of these ceramics have good frequency stability and temperature stability. In this study, the excellent energy storage performance of the ceramics prepared by the buried sintering method provides an effective idea for the design of lead-free ferroelectric ceramics with high energy storage performance and greatly expands its application field.

Ultra-large strain response in BNT-BT-KNN thin films boosted by electric field-induced inversion of long-range ordered polarization

Bismuth sodium titanate (BNT)-based piezoelectric materials are the most promising candidates for lead-free actuator applications. With the request for integration and size miniaturization of devices, it is urgent to develop thin films for microdevices to be compatible with semiconductor processes. Through composition engineering, BNT-based thin films were fabricated on silicon substrates, with ultra-high strain response and negligible hysteresis in strain curves. The DC-dependent and temperature-dependent dielectric properties were collected to investigate the relaxor state of thin films. The structure and polarization transition and evolution as a function of electric field and time were analyzed based on the electric characterization, in-situ Raman measurements, and dynamics PFM. The reversible phase transition and polarization order-disorder transformation are the most significant features for reaching a large strain of >1.6% in BNT-based thin films.

Effect of A-site excess on the shape memory effect of sodium bismuth titanate ceramics

The impact of A-site excess on the shape memory effect of Na0.5Bi0.5TiO3 ceramics was investigated. We found that the recoverable plastic-like strain was increased by more than 10 % by A-site excess. The enhancement is attributed to the change in crystal structure from a rhombohedral phase to a monoclinic one, which further changes the phase transition behavior between the ferroelectric and nonpolar phases. Suppression of grain size and the generation of defects after the addition of excess Bi and Na were proposed for the appearance of monoclinic phase. This investigation proposes a viable approach to modulate the shape memory effect of Na0.5Bi0.5TiO3-based ceramics through the manipulation of the crystal structure and the associated phase transition processes, ultimately influencing the shape memory characteristics.

Enhanced comprehensive energy storage properties in Bi0.5Na0.5TiO3-based relaxor ferroelectric ceramics under a moderate electric field

Bismuth sodium titanate (Bi0.5Na0.5TiO3)-based relaxor ferroelectric ceramics have received ever-increasing interest for their potential application in dielectric capacitors owing to their sterling energy storage capability. Herein, the perovskite end-member Ba(Fe0.5Nb0.5)O3 (BFN) was incorporated into 0.7Bi0.5Na0.5TiO3-0.3SrTiO3 (0.7BNT-0.3ST) ceramics to improve the relaxor characteristics and refine the grain, leading to slim polarization–electric field (P–E) hysteresis loops and enhanced electric breakdown strength. Particularly, the 0.85(0.7BNT-0.3ST)-0.15BFN ceramics achieved a high recoverable energy density of 5.7 J/cm3 and a high energy storage efficiency of 86.4% under a moderate electric field of 390 kV/cm. Additionally, remarkable stability in frequency, cycling, and temperature and excellent charge/discharge behavior were achieved at the same time. The above findings reveal that BFN-modified BNT-ST ceramics display greatly improved comprehensive energy storage properties, making them promising candidates in the field of electrostatic energy storage.

Strong magnetoelectric coupling in novel Na0.5Bi0.5TiO3–BaFe12-2xCoxTixO19 multiferroic composite

Multiferroic composites of sol-gel synthesized Sodium Bismuth Titanate (Na0.5Bi0.5TiO3) and Co–Ti substituted Barium Hexaferrite (BaFe12-2xCoxTixO19; x = 0.0, 0.5, 1.0, 1.5 and 2.0) in the ratio 3:1 was synthesized through ceramic route. Successful formation of R3c rhombohedral and P63/mmc hexagonal phases corresponding to Na0.5Bi0.5TiO3 and BaFe12-2xCoxTixO19 respectively was confirmed from the XRD and Rietveld refinement pattern. The frequency and temperature dependence of dielectric constant and loss of the composite systems exhibited typical dispersion behaviour which could be understood using the Maxwell-Wagner model. Substituted samples showed enhanced dielectric behaviour where dielectric constant was observed to increase while loss tangent decreased. Using the Universal Jonscher's Power law (JPL), conductivition mechanisms of the composite systems were studied from the ac conductivity behaviour which revealed that the x = 0.0 sample followed Non-overlapping Small Polaron Tunnelling (NSPT) model while the remaining samples followed the Correlated Barrier Hopping (CBH) model. The complex impedance and Nyquist plot analysis showed the enhancement of resistive property in the x≠0 systems. Magnetic hysteresis loop measurements were conducted, and the associated parameters were determined with the assistance of the Law of Approach to Saturation (LAS). Favourable reduction in the magnetic anisotropy was observed indicating the disturbance of magnetic spin structure in the hexaferrite phase. The P-E loops established the novel room temperature multiferroic nature of the composite systems. Significant magnetoelectric coupling was detected at room temperature in all samples, with the x = 0.5 sample exhibiting the highest value of approximately 59.81 mV/cmOe. These desirable properties suggest that the composites may find future device applications as in magnetically tunable energy harvesting devices and self-powered magnetoelectric sensors in the future.

Improvement of thermomechanical and dielectric properties of thermoplastic polyurethane using bismuth sodium titanate/carbon nanotube hybrid fillers

AbstractThe development of innovative composite materials through the amalgamation of thermoplastic polyurethane (TPU) with bismuth sodium titanate (BNT) and carbon nanotube (CNT) fillers was investigated. Before the composite fabrication, the fillers' surfaces were treated to enhance their compatibility with the TPU matrix. Hybrid fillers of BNT and CNTs were fabricated by mixing the two types of filler particles through ball milling and subsequently annealing the mixture at 250°C. Melt‐blending and injection molding were utilized to synthesize the composites at 210°C processing temperature. The prepared composites showed significantly enhanced thermal conductivity, dielectric constant, thermal stability, and thermomechanical properties compared with the neat TPU matrix. For instance, the dielectric constant was enhanced by 340% upon the inclusion of 40 wt.% BNT and CNT fillers compared to the neat TPU matrix (40CBNT‐TPU has 13.2). In particular, the inclusion of BNT‐CNT particles in the TPU matrix improved the thermal conductivity of the TPU matrix by 1180% tremendously as compared to neat TPU (40CBNT‐TPU has 2.6 W/(m.K)).Highlights Crystalline bismuth sodium titanate (BNT) is fabricated. Degradation of 8 wt.% of the IPDI‐treated BNT proves surface treatment. Dielectric constant (DC) improved by 340% compared to neat TPU. Thermal conductivity (TC) enhanced 11.4 times compared to neat TPU. Improvement in TC and DC will make it applicable in electronic materials.

Achieving Ultrahigh Electrocaloric Response in (Bi0.5Na0.5)TiO3-Based Ceramics through B-Site Defect Engineering.

Lead-free electrocaloric (EC) ferroelectrics are considered ideal for the next generation of environmentally friendly solid-state refrigeration materials. However, their inferior performance compared to lead-based materials significantly restricts their potential application. According to phase-field simulations, it is predicted that the pinning effect of a moderate number of defects can effectively enhance the reversible polarization response associated with the entropy change. Herein, sodium-bismuth titanate (BNT) ceramics with high spontaneous polarization are selected to construct B-site defects by introducing Li+ and Nb5+. Under an electric field of 6 kV mm-1, ultrahigh EC temperature changes of ΔTpos = 1.77 and ΔTneg = 1.49 K are achieved at 65 °C by direct measurement (ΔTneg > 1 K over 55-120 °C). Furthermore, ΔTneg remains above 0.70 K in the temperature range from 25 to 130 °C, exhibiting immense potential for practical applications. This study offers a promising direction for optimizing the EC response in defect systems.

Surface ferromagnetism of lead-free ferroelectric bismuth sodium titanate materials

The role of complex surface defect on the magnetic at the (110) surface of bismuth sodium titanate (Bi0.5Na0.5TiO3) was discussed based on the first-principles calculation. The first-principle calculations for various types of surface defects exhibited the existence of magnetic moments for selected chemical and position defects. Specifically, Na and Bi vacancies induced large magnetic moments of 0.52 µB/f.u and 0.50 µB/f.u, respectively, which were larger than that of Ti vacancies of 0.01 µB/f.u. Interestingly, oxygen vacancies did not induce local magnetic moments. Furthermore, significant magnetic moments of 0.50 µB/f.u and 0.49 µB/f.u were obtained for Na and Bi interstitial defects, while the local magnetic moments were slightly achieved around 0.03 µB/f.u and 0.04 µB/f.u for Ti and O interstitial defects, respectively. Anti-site defects between Bi and Na at A-site in perovskite ABO3 structure exhibited magnetic moments of 0.55 µB/f.u for Na anti-site at Bi-site and 0.39 µB/f.u for Bi anti-site at Na-site. Interestingly, anti-site defects between the A-site and B-site in perovskite ABO3 structure resulted in larger magnetic moments, with values of 0.57 µB/f.u and 0.53 µB/f.u obtained for Ti anti-site defects at the Bi-site and Na-site, respectively. Additionally, magnetic moments of 0.50 µB/f.u and 0.54 µB/f.u were achieved for Bi and Na anti-site defects at the Ti-site, respectively. We expected that our work further contributed to the understanding of the role of surface defects in the magnetism of Bi0.5Na0.5TiO3 materials in integrating ferromagnetic properties into lead-free ferroelectric materials for smart electronic device applications.

Influence of NaOH Concentration on Structural, Morphological, Optical, and Electrical Characterization of Perovskite Sodium Bismuth Titanate Prepared by Hydrothermal Method

The hydrothermal method successfully prepares a lead-free sodium bismuth titanate (NBT) perovskite film. The prepared films were studied structurally, and morphologically using X-ray diffraction, and field-emission scanning electron microscopy (FESEM), respectively. Varying the concentration of NaOH showed a noticeable effect on the properties studied. Good crystallization of NBT perovskite films without impurities was obtained at 18 and 20 M concentrations, where the crystalline size was 14 nm according to the Scherer equation. Also, when varying the concentration of NaOH, a similar film thickness was obtained through a cross-section of the FESEM images. It was observed that there was a difference in the intensity of the peaks of the photoluminescence spectra of the prepared films with a change in the concentration of NaOH, which confirms a change in the concentration of oxygen vacancies. The activation energy of the prepared films was deduced from the Arrhenius plot, as it showed small values in the films prepared with a low concentration of NaOH. The results showed that the maximum value of mobility of NBT films was at 20 M of NaOH concentration through the Hall Effect.

Recent advances in processing, morphological evolution and applications of bismuth sodium titanate nanoceramics

Nanostructured hybrid functional perovskite materials are an exciting domain of electroceramic materials and have created attention among researchers due to the coexistence of multiple properties like piezo and ferroelectricity. It offers a broad range of applications in optics and electronics technology. One of its kinds, bismuth sodium titanate (Bi0·5Na0·5TiO3-BNT) nanomaterials, possesses an integral and significant role in advanced electronic industries. This article aims to systemize the deliberation related to the development of bismuth sodium titanate-based nanomaterials, including the study of nanomaterial morphology mechanism, fabrication methods, crystal structure, and its role in many other novel applications. This work focuses on analyzing behavior based on synthesis methods, the proposed approaches for optimizing morphology, and current challenges. Challenges and opportunities connected with the BNT nanomaterials are elaborated. This study could motivate young researchers to study and develop novel BNT-based nanomaterials so that we could get the best out of the research.

Efficient piezocatalytic properties of Na0.5Bi0.5TiO3 nanoparticles for dye degradation and hydrogen peroxide production

Piezocatalysis has emerged as a promising environmental remediation technique, and the exploration of environmentally friendly and high-performance piezocatalysts is crucial for their practical applications. In this work, the bismuth sodium titanate (Na[Formula: see text]Bi[Formula: see text]TiO3 (NBT)) exhibited efficient piezocatalytic activity toward typical organic pollutants degradation, including acid orange 7, methylene blue, rhodamine B and methyl orange. Notably, rhodamine B was degraded by 98.1% within 30[Formula: see text]min with a reaction rate constant of 0.130[Formula: see text]min[Formula: see text]. Furthermore, the NBT achieved a hydrogen peroxide production efficiency of 538[Formula: see text][Formula: see text]mol/g⋅h without the sacrificial agent, indicating that the NBT is a superior piezocatalyst for dye degradation and hydrogen peroxide generation. This work demonstrated that by using mechanical energy, the NBT can be used for degrading organic pollutants in wastewater and hydrogen peroxide generation.

Enhancing life cycle product design decision-making processes: Insights from normal accident theory and the satisficing framework

Life Cycle Assessment (LCA), a computational tool for enabling sustainable product design decision making, faces challenges in the interpretation phase, where conclusions are drawn for improvement recommendations. This necessitate the need to incorporate into LCA management-relevant theoretical underpinnings to strengthen decision-making processes. Comparative LCA case studies of lead-based piezoelectric material (lead zirconate titanate – PZT) and lead-free alternatives (potassium sodium niobate – KNN, sodium bismuth titanate – NBT), was employed to demonstrate how two theoretical lenses, namely Normal Accident Theory (NAT) and the Satisficing Framework, are used inductively to enhance decision making regarding unintended consequences in the value chain. By operationalising NAT, which has hitherto focused on the consequences of physical accidents, as a life cycle engineering-based methodology, NAT attributes of interactive complexity and tight coupling was revealed in piezoelectric materials, based on environmental systems’ predictability, observability, and applicability. This led to the introduction of Environmental Impact Accident (EIA) as a new concept, facilitating an early assessment of the associated complexities influencing the sustainability credentials of piezoelectric materials whilst informing mitigation strategies. However, when considering multiple objectives that conflict or trade-off between alternative piezoelectric materials with different environmental and health impacts across the value chain, a conundrum is created but resolved using the Satisficing Framework. The paper concludes by proposing theoretical and practical policy options for incorporating LCA into product life cycle decision making.

Impact of sintering time on structure and electrical properties of Pb-free BNT-BKT-SZ ceramics

The work focuses on preparing and characterising BNT-based ceramics via a solidstate method. To investigate the phase, microstructure, and physical and electrical properties of BNT-based ceramics.Lead-free piezoelectric bismuth sodium titanate – bismuth potassium titanate – stronsium zirconate (BNT-BKT-SZ) ceramics were fabricated by the solid-state reaction method. The effect of sintering temperature with soaking times of 2, 4, and 6 h at 1150C on structural, microstructure, density, porosity, and electrical properties was examined. The phase formation of the ceramics was examined using X-ray diffraction (XRD). Scanning electron microscopy (SEM) (JEOL JSM5910LV) was employed to investigate ceramic microstructure. The bulk density and mechanical properties of the sample were measured using Archimedes’ method, respectively. The electrical properties of ceramics, such as dielectrics, ferroelectrics, and piezoelectrics, were investigated.XRD showed all samples had a single perovskite structure and no secondary phase. All sintered samples at different temperatures have a coexisting phase boundary between the rhombohedral phase and the tetragonal phase. The sintered ceramic at 1150C with a soaking time of 4 h shows a maximum density of 5.89 g/cm3. In addition, the temperature at which the sintering process is carried out substantially impacts the electrical characteristics. Dielectric and electric field-induced strain (Smax) properties that sintered at 1150C with a soaking time of 4 h exhibited the highest values of 4.489 and 0.39% (d33* of 650 pm/V), respectively.The impact of the coercive field on the electrical breakdown characteristics of ceramics should be investigated further in the course of research that has to be carried out.The characterisation confirmed the effects of sintering temperature on the physical, phase, microstructure, and electrical properties of BNT-based ceramics.Such research demonstrates a suitable sintering temperature for producing BNT-BKT-SZ. The mechanical and electrical properties of a material are dependent on its sintering parameters. The ceramic system is suitable for piezoelectric and/or energy storage applications.

Origin of Polarization in Bismuth Sodium Titanate-Based Ceramics.

The classical view of the structural changes that occur at the ferroelectric transition in perovskite-structured systems, such as BaTiO3, is that polarization occurs due to the off-center displacement of the B-site cations. Here, we show that in the bismuth sodium titanate (BNT)-based composition 0.2(Ba0.4Sr0.6TiO3)-0.8(Bi0.5Na0.5TiO3), this model does not accurately describe the structural situation. Such BNT-based systems are of interest as lead-free alternatives to currently used materials in a variety of piezo-/ferroelectric applications. A combination of high-resolution powder neutron diffraction, impedance spectroscopy, and ab initio calculations reveals that Ti4+ contributes less than a third in magnitude to the overall polarization and that the displacements of the O2- ions and the A-site cations, particularly Bi3+, are very significant. The detailed examination of the ferroelectric transition in this system offers insights applicable to the understanding of such transitions in other ferroelectric perovskites, particularly those containing lone pair elements.