Bismuth Titanate Research Articles

Ion dynamics of non-stoichiometric Na0.5+xBi0.5-xTiO3-δ: A degradation study

Sodium bismuth titanate, a well-known piezoelectric material is reported as the new family of fast oxide ion conductors. In the current study, we investigated the influence of A-site non-stoichiometry on the electrical conductivity and ion dynamics of sodium bismuth titanate ceramics. For this, we synthesized the system Na0.5+xBi0.5-xTiO3–δ with x = −0.02, −0.01, 0.00, 0.01 and 0.02. The samples synthesized were almost single phase with rhombohedral (R3c) symmetry. The scanning electron micrographs showed the formation of dense grains with bulk density > 96%. The microstructure appeared to be very sensitive to non-stoichiometry. The conductivity data isotherms with frequency showed non-linear variation and were well fitted with Jonscher power law. We have observed super linear frequency dependent behaviour in Bi rich composition and sub-linear behaviour with the increase in Na content. To study the degradation mechanism, Na0.5+xBi0.5-xTiO3-δ (x = −0.01, 0.00, 0.01) samples were kept in reducing environment for 48 h. Further, for the analysis of conduction mechanism and the qualitative/quantitative estimation of charge carriers before and after reducing conditions, various models were used.

Lattice Structure and Dynamics of Two-Layer Heterostructures of Barium–Strontium Titanate and Layered Bismuth Titanate of Various Thicknesses on a Magnesium Oxide Substrate

The lattice structure and dynamics of single-crystal Bi4Ti3O12 with a thickness from 4 to 430 nm on a (001)MgO substrate with a previously deposited Ba0.4Sr0.6TiO3 sublayer (4 nm) have been studied. The two-layer structures were prepared by radio-frequency sputtering of ceramic targets of the corresponding compositions. The X-ray diffraction studies performed at room temperature have shown that, in this heterostructure, axis c of the Bi4Ti3O12 unit cell is perpendicular to the substrate, and direction [100] has an angle of ±45° to the [100]MgO direction. At the thicknesses of Bi4Ti3O12 to ~40 nm, the film unit cell is compressed in the direction of a normal to the substrate plane and extended in the conjugate plane, and the sign of the deformation is changed at large thicknesses. It is found that the phonon mode frequency in the Bi4Ti3O12 film shift and additional peaks appear in the Raman spectra, which demonstrates an increase in the degree of monoclinic distortion of the film crystal structure as compared to the crystal structure.

Effect of the number of layers on surface topography of bismuth-titanium coatings

The objective of this research is to perform a topographic characterization by atomic force microscopy of the surface of bismuth titanate (Bi/Ti) coatings varying the number of layers deposited on the substrates, considering that there were not results of reported studies in which these precursors were used. It is important to analyze the surface behavior of these coatings as a first phase of future researches to establish the viability of possible uses and applications in biomedical industry. The films were synthesized by the sol-gel method from bismuth nitrate pentahydrate and titanium tetrabutoxide. Subsequently, by means of the spin- coating technique, the coatings were deposited on 316L stainless steel in monolayer and bi- layer, as this type of steel has been widely used for medical applications due to its good compatibility. The roughness values of each of the coatings were also determined. It is concluded that there is a relationship between the topography of the surface and the roughness values of the films with respect to the concentration of the precursors, the number and the speed of centrifugation of the layers deposited on the substrate. High concentrations of titanium tetrabutoxide effect on the good densification characteristics of the coatings.

Characterization of the anticorrosive properties in bismuth-titanate films obtained by the sol-gel method

Sol-gel synthesis has been used since 1950 to prepare oxides. The method is attractive because the processes of obtaining the oxides are developed at room temperature; products with high purity and homogeneity are obtained, and allow the combination of several types of oxides: silicon, zirconium, titanium, aluminum, bismuth, and cerium. Sol-gel has been used to make ceramic composites with anticorrosive properties on stainless steel substrates. A class of stainless steel widely used in biomedical applications, especially in the treatment of fractures, 316L is its low economic cost relative to other materials such as titanium. Once the steel implant is inside the human body it comes into contact with body fluids that contain chloride ions. The fluid-implant interaction develops a corrosive process on the metal surface. The corrosive products of iron diffuse in the body causing tissue damage. As a possible solution to this problem, the objective of the investigation was to obtain a bismuth-titanium oxide using the sol-gel method and apply it on 316L stainless steel substrates. Bismuth nitrate pentahydrate and titanium tetrabutoxide were used as precursors. The anticorrosive response was evaluated in a simulated physiological solution, Ringer’s solution, by electrochemical impedance spectroscopy and potentiodynamic polarization curves. It is concluded that the coatings function as a corrosion barrier preventing the chloride ions Ringer’s solution reach the metal surface.

Lanthanide Ion-Doped Bismuth Titanate Nanocomposites for Ratiometric Thermometry with Low Pump Power Density

The sensing of temperature is closely related to human life. The noncontact ratio temperature measurement method has extensive applications in biochemical monitoring and industrial production. Howe...

Tunable structure and intensive upconversion photoluminescence for Ho3+-Yb3+ codoped bismuth titanate composite synthesized by sol-gel-combustion (SGC) method

Ho3+ and Yb3+ codoped bismuth titanate (BTO) composite powders with infrared to visible upconversion luminescence (UCL) function were prepared by SGC method. The effects of Ho3+ and Yb3+ doping content on the structure and property were investigated for BTO: xHo, 0.2 Yb (x = 0, 0.02, 0.04, 0.06, 0.08, 0.1) and BTO: 0.02Ho, yYb (y = 0.1, 0.2, 0.3, 0.5, 0.7, 0.9) samples. All the samples include three bismuth titanate phases (Bi4Ti3O12, Bi2Ti2O7, and Bi20TiO32), and the phase proportion can be tuned by changing Ho3+ and Yb3+ doping content. These powders are well crystalized with honeycomb-like microscopic structure, and with good absorption for 233 nm, 310 nm and 975 nm wavelength. The band gap can be tuned from 3.53 eV to 4.03 eV when increasing Yb3+ content from y = 0 to y = 0.9. A strong 530–580 nm green emission band and a relative weak 630–690 nm red one corresponding to Ho3+: 5S2 → 5I8 and 5F5 → 5I8 transitions appear in the UCL spectra for all the BTO: Ho, Yb samples when pumped at 980 nm. The emission intensities can well be tuned with various Ho3+ and Yb3+ content. The optimal UCL was obtained in BTO: 0.02Ho, 0.5 Yb for all the prepared samples. The energy transfer mechanism is analyzed by building a two-photon energy transfer model, which is proved by the relationship between emission intensities and pumping power measurement. The concentration quenching of Ho3+ is caused by cross relaxation of CR1 and CR2 (Ho: 5F4, 5S2 + 5I8 → 5I4 + 5I7) and by CR3 (Ho: 5F4, 5S2 + Yb: 2F7/2 → Ho: 5I6 + Yb: 2F5/2) for Yb3+ quenching. The mean luminescence lifetime (τm) from Ho: 5S2 decreases monotonously with the increase of Ho3+ and Yb3+ content.

Visible-light-driven photocatalytic degradation of naproxen by Bi-modified titanate nanobulks: Synthesis, degradation pathway and mechanism

Naproxen (NPX) as one of the typical pharmaceuticals and personal care products (PPCPs) has been constantly detected in aquatic environment recently which has potentially hazard to the human health and ecosystem. However, the practical applicability of photocatalysts in degradation of NPX is still restricted by challenges that most nanomaterials need to be stimulated by ultraviolet light and their limited photocatalytic activity under visible light. Therefore, we synthesized bismuth titanate nanobulks (Bi-TNB) through the two-step method of hydrothermal-calcining. The crystal structure, morphology, UV–vis diffuse reflectance spectra and surface adsorption performance of the as-prepared were investigated by XRD, SEM, UV–vis and BET. Several parameters which might influence the degradation efficiency were studied including initial NPX concentration, catalyst dosage, solution pH and concentration of anions, cations and humus. The results indicated that more than 99.9% of NPX (0.25 mg/L) was removed by Bi-TNB (0.5 g/L) at pH = 7. Reactive species scavenging experiments indicated that h+ and O2·− were the dominant active species involved the degradation of NPX. In photodegradation process, NPX was firstly decarboxylated and then further photocatalytic oxidized to form carboxylic acids of lower molecular weights and would be finally transformed into CO2 and H2O. PPCPs coexistence experiment showed that acetaminophen would hinder the removal of NPX by Bi-TNB. Both the reaction in different water matrices and degradation under the condition of sunlight indicated that Bi-TNB could be applied in degradation of NPX in environmental water systems. This study provides a new strategy for enhancing material photocatalytic performance to be used in practical applications.

Ferroelastic properties and compressive stress-strain response of bismuth titanate based ferroelectrics

Ferroelectric materials have been widely studied for applications in numerous devices due to their controllable ferroelectric/ferroelastic properties under electric field or mechanical stress. Recently, a type of bismuth layer-structured ferroelectrics, W/Cr co-doped BIT ceramics, has attracted much attention due to its high Curie temperature, large spontaneous polarization, and particularly enhanced ferroelectric properties. Nevertheless, as a significant consideration for the reliability and durability of devices, the mechanical properties associated with ferroelastic behaviors of this type of ceramics are generally ignored. In this study, a type of W/Cr co-doped BIT ceramics with optimal chemical composition of Bi4Ti2·95W0·05O12.05+0.2 wt% Cr2O3 (BTWC) was synthesized via the solid-reaction technology. Ferroelastic domain structures and ferroelastic switching behaviors together with mechanical failure properties of the sintered ceramics were investigated in details. PFM observations reveal the existence of pseudo-90° and -180° ferroelastic domain structures in BTWC ceramics. The nonlinear deformation of stress-strain curve originates from ferroelastic domain switching induced by mechanical stress of sufficient magnitude. Moreover, the ferroelastic switching plays a significant role in improving the fracture toughness of BTWC ceramics. Additionally, the ceramics sintered at higher temperature are expected to exhibit a better ferroelastic switching behavior yet lower failure stress. The work can provide design consideration of loading conditions for practical applications of BTWC ceramics.

Electrochemical sensor for the detection of lead ions of B-site-doped bismuth titanate perovskite thin film

The perovskite thin film was fabricated using cobalt (Co)-doped B-site on bismuth titanate (Bi4Ti3−xCoxO12) on FTO substrate by spin coating technique. The fabricated substrate was annealed at 700 °C and employed as an electrochemical sensor for the detection of lead ions. The obtained device was investigated for their structural, optical and morphological features using X-ray diffraction (XRD), UV–V is spectroscopy (UV), photoluminescence and scanning electron microscopy (SEM). XRD patterns reveal that the grains were orientated along c axis with (117) plane providing decreased crystallite size upon increasing dopant concentrations in BTO. UV–Vis diffusion reflectance spectrum showed that bismuth titanate thin films exhibited good optical transmittance in the visible region. BTO thin films displayed particles are in spherical in shape which was confirmed using SEM. The acquired thin film was employed as an electrochemical sensor for the detection of lead ions. The detection technique was carried out using cyclic voltammetry which delivered high sensitivity. On examining the physical and chemical properties of the obtained product, it can also be further employed as real-time applications.

Synthesis of BixTiyOz/TiO2 heterojunction with enhanced visible-light photocatalytic activity and mechanism insight

Four bismuth titanate and titania composites were firstly synthesized by the mixed alcohol-thermal method using same material ratio. The as-prepared samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Energy dispersive X-ray spectrometry (EDS), Ultraviolet–visible (UV–Vis), Brunauer-Emmett-Teller (BET) surface area test and Photocurrent response curve. The results indicated that the composition and morphology of composites were affected by the glycerol ratio and calcination temperature. The mineralized rate of titanium salt and bismuth salt could be adjusted by the proportion of glycerol, which changed the ratio of titanium oxide to bismuth oxide in the system and formed the different bismuth titanate composites. The photodegradation efficiency of tetracycline hydrochloride (TC), chlortetracycline hydrochloride (CTC) and methylene blue (MB) by the as-prepared composites were greater than that of pure TiO2 under visible light. The free radical trapping experiments also proved that superoxide ion radicals (·O2−) and holes (h+) played a leading role in photocatalytic degradation, and the possible photocatalytic degradation mechanism of the composites was also discussed.

Amphotericity-spectroscopy correlations in Eu doped sodium bismuth titanate (Na0.5Bi0.5TiO3)

Optical characteristics of a doped material depend on the site wherein the dopant resides. In mixed A-site perovskites, the dopant has several possibilities. This, in turn, correlates with the emission spectrum of the doped material. Here we choose Eu3+ as the dopant since it is a well-known and efficient red-luminophore. Sodium bismuth titanate (NBT-Na0.5Bi0.5TiO3) is selected as a host due to its ability to accommodate Eu over large concentration windows while maintaining optical activity. For compositions x ≥ 0.04, we show that Eux:NBT has amphoteric behavior (i.e., simultaneous dopant substitution in two competing sites). Eu3+ occupancy in Bi and Ti-sites are quantitatively estimated using Rietveld refinement. Also, the appearance of A1g breathing vibrational mode (830–860 cm−1) in Raman spectra shows the presence of Eu3+ on the Ti-site. Photoluminescence (PL) emission shows sharp and intense bands at ∼592 nm, ∼615 nm, and ∼687 nm, and one weak band at ∼652 nm, corresponding to f–f transitions of Eu3+. To evaluate the optical characteristics with varying site-substitution of Eu3+; Judd–Ofelt parameters and radiative properties are calculated for the first time in this mixed A-site titanate system. From the values of asymmetric ratios; Eu3+ ion is shown to occupy the non-centrosymmetrical sites (Bi-sites) of NBT. However, at x = 0.04, Ω2 < Ω4, which indicates long-range effects and hence Eu occupancy in centrosymmetric sites (Ti-sites). This study opens up avenues for further exploration of correlations between dopant-concentration, amphotericity, and spectrochemical response in other systems. The amphoteric behavior of dopants can tune emission intensities and produce multi-emission colors using a single-dopant. This would have implications for luminescence-based applications.

Fabrication of bismuth titanate nanosheets with tunable crystal facets for photocatalytic degradation of antibiotic

The synergism between different surface facets of semiconductor with optimal ratios can contribute to obtain enhanced photocatalytic degradation performance. Herein, a bismuth-based material Bi4Ti3O12 exposed with {001} top facets and {010}/{100} lateral facets was prepared by the molten-salt method. More importantly, the ratio of different exposed facets could be controlled by adjusting the synthesis temperature of molten-salt synthesis process. The as-prepared Bi4Ti3O12 exposed with the optimal ratio of {001} top facets to {010}/{100} lateral facets exhibited the enhanced degradation activity of tetracycline hydrochloride (TC-HCl) under irradiation. The rate constant of optimal sample reached 0.904% min−1, over 3.3 times as compared with that of the counterpart with higher proportion of {001} facets. Besides, active species trapping experiments, photoelectrochemical measurements and selective photodeposition tests were used to illuminate the photocatalytic degradation mechanism. According to that, the enhanced degradation activity could be ascribed to crystal facet synergism which can promote photoinduced carrier separation. This work can give insights into designing and constructing other two-dimensional (2D) bismuth-based materials with the aim of enhancing photocatalytic degradation performance.

Influence of co-modification with tungsten and tantalum on the crystal structure and electrical properties of bismuth titanate ceramics

Bismuth titanate Bi4Ti3O12 (BIT) based lead-free piezoelectric ceramics with the formula Bi4Ti3-2xWxTaxO12 (abbreviated as BITWT-x, x = 0, 0.015, 0.03, 0.04, 0.045, 0.05) were fabricated by the conventional solid-state sintering method. The effect of W and Ta doping on the crystal structure and electrical properties of BITWT-x ceramics were investigated. BITWT-x ceramics had an orthogonal phase, and crystal structural distortion of W/Ta co-doped BITWT-x based ceramics was higher than that of BITWT-0 ceramics, which improved the ferroelectricity and the piezoelectric property. The ferroelectricity (Pr = 7.78 μC/cm2) of BITWT-0.03 ceramics was better than that (Pr = 0.84 μC/cm2) of BITWT-0 ceramics. The piezoelectric property (d33) was enhanced, and the highest d33 of BITWT-0.04 ceramics was 21.4 pC/N. Moreover, the d33 of the BITWT-x ceramics at 600 °C still kept 80% of its original d33 when the value of x was in the range of 0.03–0.045. Donor ions W6+ and Ta5+ reduced ionic conductivity (oxygen vacancies) and electron conductivity (holes), then increased the resistivity of BITWT-x ceramics (ρ400 °C = 1.82 × 108 Ω cm, x = 0.03). However, the enhanced effect reached a saturated state when x was 0.03. Thus, the BITWT-x ceramics were suitable for the high-temperature application.

Ab Initio and Experimental Insights on Structural, Electronic, Optical, and Magnetic Properties of Cr-Doped Bi2Ti2O7

Combined ab initio and experimental study of Cr doping into bismuth titanate pyrochlore was carried out for the first time. Accurate first-principles density functional theory calculations were performed considering a Hubbard U correction (DFT+U) to account for on-site Coulomb interactions of the Cr 3d states. The possibility to synthesize a novel pyrochlore-type compound with a high dopant content Bi1.5Cr0.5Ti2O7 (Bi site doping) in a fine powder state was shown via coprecipitation method, while the single-phase Bi2Ti1.5Cr0.5O7 (Ti site doping) could not be obtained. Detailed descriptions of thermostability, structural, optoelectronic, and magnetic properties of Cr-doped pyrochlores in the fine (particles size 100-300 nm) and "bulk" (1-50 μm) powder states are presented based on the well-matched results of theoretical and experimental investigations. According to the Rietveld refinement of the X-ray diffraction data, Bi1.5Cr0.5Ti2O7 compound is an A-site deficient pyrochlore (Bi1.38Cr0.30)(Ti1.84Cr0.16)O6.44 with chromium distribution between both cationic sites. Metastability of fine powder Cr-containing pyrochlore phase was revealed during long-thermal annealing, while the bulk powder sample was stable up to its melting point 1230 °C. According to the study of electronic structure and optical properties, Cr-doped pyrochlores are wide-band semiconductors with light absorption in the range of 300-500 nm and perspective as photocatalytic active materials under visible light irradiation. Paramagnetic behavior with effective magnetic moment 3.92 μB (Bi1.6Cr0.1Ti2O7-δ) and 3.01 μB (Bi1.5Cr0.5Ti2O7) was experimentally observed. All chromium in magnetically diluted pyrochlore Bi1.6Cr0.1Ti2O7-δ exists in the form of Cr3+ monomers, whereas in the more concentrated magnetic Bi1.5Cr0.5Ti2O7 composition Cr3+-O-Cr3+ dimers may also be present, with a fraction equal to 0.39. This investigation constitutes the first approach to the electronic, structural, optical, and magnetic properties of d-elements doped bismuth titanate pyrochlores from experimental and theoretical viewpoints, emphasizing the power of DFT+U to provide insights and to complement the experimental characterization of these new compounds.

Hydrothermal growth of Bi2Ti2O7/TiO2 and Bi4Ti3O12/TiO2 heterostructures on highly ordered TiO2-nanotube arrays for dye-sensitized solar cells

Secure solar energy has been considered to be a possible way to alleviate the energy crisis. Using a hydrothermal reaction, functional heterostructures, including Bi2Ti2O7 and Bi4Ti3O12, were assembled on highly ordered TiO2-nanotube arrays that were prepared via a two-step anodic-oxidation method. The loading of the heterostructure onto the arrays was controlled by adapting the reaction temperature and alkalinity of the hydrothermal reaction. The samples were assembled into dye-sensitive solar cells to study their photoelectric performance. The optimal photoelectric-conversion efficiencies of Bi4Ti3O12/TiO2 (synthesized at 200 °C and pH 13.7) were 2.3 times greater than those of pure TiO2-nanotube arrays. The photoelectric property was enhanced due to the increase in the photoabsorption that originated from the introduction of the dyes, as well as the improvement in the charge-separation efficiency, which was derived from the matching of the energy-bands between the bismuth titanate and TiO2. The ferroelectric properties of Bi4Ti3O12 also played an important role in the enhanced photoelectric property.

Influence of sintering temperature on ion dynamics of Na0.5Bi0.5TiO3-δ: Suitability as an electrolyte material for SOFC

Sodium bismuth titanate samples with different morphology were synthesized via varying the sintering temperature from 1000 to 1150 °C. The conductivity was significantly affected with the morphology of the system. The dynamics of ions was understood from the conductivity spectra. The dc conductivity, hopping frequency and exponent values were extracted from the conductivity spectra analysis. The impedance and modulus spectroscopy along with exponent behaviour suggested short range hopping for the sample sintered at 1000 °C and followed Ghosh scaling instead of Summerfield scaling. While long-range hopping was observed for the samples sintered at 1150 °C and it followed both the Summerfield scaling and Ghosh scaling. Moreover, the stability of the sample is checked in reducing atmosphere.

Influence of Na, Sm substitution on dielectric properties of SBT ceramics

Abstract Sodium, Samarium substituted Strontium Bismuth Titanate (Sr1-xNaxSmxBi4Ti4O15 –SNSBT where x = 0.1, 0.2, 0.3, 0.4) piezoelectric ceramics are synthesized by solid-state sintering route using high energy planetary ball mill for 20 h in presence of Acetone and Aqua media. Calcination and sintering are carried out at 800 °C and 1160 °C respectively in Air using programmable furnace. 1 mm thickness and 10 mm diameter circular pellets are prepared by uniaxial hydraulic press at 4 tons/cm2 pressure. Larger surfaces of the sample are coated with silver in order to have good electric contact for properties study. X-Ray Diffraction and Scanning Electron Microscopy studies are carried out to identify the orthorhombic structure, grain size and grain orientation. SEM shows densified and plate like structure of SNSBT. Experimental density is found to be more than 95% of theoretical density. Tolerance factor is decreased with increase of Na, Sm concentrations of SNSBT ceramics. Dielectric measurements are conducted as function of temperature at various frequencies and phase transition temperature (Tc) is enhanced by addition of Na, Sm of SBT.

Optical multi-functionalities of Er3+- and Yb3+-sensitized strontium bismuth titanate nanoparticles

Multi-functional up-conversion (UC) phosphors are highly desirable for many potentially technological applications. Here, Er3+- and Yb3+-doped SrBi4Ti4O15 (SBT:xEr3+/yYb3+) UC nanoparticles (NPs) have been successfully synthesized for the first time by a convenient EDTA-citrate approach. The structures and morphologies were characterized by powder X-ray diffraction, Fourier transform infrared reflectivity spectra, scanning electron microscopy, and transmission electron microscopy. Under 980 nm excitation, SBT:xEr3+/yYb3+ UCNPs exhibited bright green and weak red emissions. The UC emission properties were disclosed to be tightly dependent on the Yb3+ and Er3+ concentration and the involved UC mechanism was discussed. More importantly, the noncontact optical thermometric ability were assessed based on the thermo-responsive fluorescence intensity ratio (FIR) technique and the maximum sensitivity (Smax) of SBT:0.15Er3+/0.15Yb3+ UCNPs is about 0.0036 K–1. Excellent repeatability and stability were proven by the thermal-cycling measurements. Furthermore, prominent photo-thermal (PT) effect was obtained with the temperature coefficients (η) being 0.24 and 0.49 °C∙mm2/mW for SBT:0.15Er3+/0Yb3+ and SBT:0.15Er3+/0.15Yb3+ UCNPs, respectively, which showed that the incorporation of Yb3+ was a promising strategy to improve the PT capability. In addition, regularly dynamic response of the PT agent under periodic laser stimulation was also observed. These results imply that SBT:xEr3+/yYb3+ UCNPs could be potentially utilized in thermometers and PT agents.

Dielectric and Raman spectroscopy studies of (Na0.5Bi0.5)TiO3 lead-free ceramic

Abstract In this study, samples of sodium bismuth titanate (Na0.5Bi0.5)TiO3 (NBT) have been prepared using the solid-state technique. Sintering was done at 1200 ºC for 4 h in air atmosphere. X-ray diffraction analysis carried out at room temperature showed the formation of a single-phase compound with a rhombohedral crystal system. Dielectric and Raman spectroscopic characterizations have been performed as a function of temperature. The dielectric study showed the existence of a diffuse phase transition around 330 ºC. The Raman spectra was fitted to the individual Raman peaks. The obtained peaks were analyzed by observing the changes in their respective peak positions and intensities with increasing of temperature. At high temperatures, the results showed discontinuous changes in the phonon frequencies across the rhombohedral-tetragonal transition.

Investigation of the mechanism of domain switching in different Na0.5Bi0.5TiO3 microstructures

Abstract Several researches have studied the physical properties of hydrothermally-synthesized low dimensional piezoelectric nanostructures. However, the obtained piezoelectric coefficient is not high and the relationship between physical properties and microstructures is still neglected. Here we report the piezoelectric and ferroelectric properties of different lead-free sodium bismuth titanate (Na0.5Bi0.5TiO3, NBT) microstructures synthesised with hydrothermal routes and give visualization of domain structures using piezoresponse force microscopy. The NBT nanowire exhibits better local piezoelectric response compared with NBT spherical aggregates and microcubes and other one-dimensional materials prepared by hydrothermal method and the large piezoelectric coefficient of nanowire was explained by observed regular stripe domain structures. Moreover, it is found that there are different domain configurations at the top and side of the nanowire under the external electrical fields, which don't change the regular stripe domain structure but lead to the movement of domain boundaries. By finite element modeling, it attributes to the different electric potential distributions from tip within the nanowire.