Barium Stannate Research Articles

Synthesis and characterization of Sm3+-doped barium stannate down-conversion nanocrystals and its application in dye-sensitized solar cells

Sm3+-doped barium stannate (BaSnO3:Sm3+) down-conversion particle was prepared via a sol-gel method with SnCl4·5H2O, BaCO3 and Sm(NO3)3 as raw materials followed by an annealing process. Differential thermal analysis (TG/DTA), X-ray diffraction analysis (XRD), scanning electronic microscope (SEM), and energy dispersive spectroscopy (EDS) confirmed the formation of BaSnO3:Sm3+ nanocrystals with a typical perovskite structure. The photoluminescence (PL) spectra indicated that the as-prepared BaSnO3:Sm3+ nanocrystals could convert UV-light to yellow light at 587 nm and effectively widen the spectra response ranges of the DSSC to the ultraviolet region. The photoelectric properties of the dye-sensitized solar cells (DSSCs) based on BaSnO3:Sm3+ photo-anodes were also investigated. The BaSnO3:Sm3+ down-conversion photo-anodes showed a much greater photovoltaic efficiency compared with the photo-anode of BaSnO3 without rear earth (RE). The photoelectric conversion efficiency of the DSSCs based on BaSnO3:Sm3+ photo-anode doping Sm3+ of 1mol% was almost twice higher than that based on pure BaSnO3 photo-anode under the simulated light irradiation.

Accurate control of stoichiometry and doping in barium stannate perovskite oxide nanoparticles.

Barium stannate (BaSnO3) is one of the most promising emerging materials for use as a transparent electrode. However, to date, its synthesis has been proven to be highly irreproducible. In this communication, we present a detailed investigation of the reproducibility issues and provide a robust approach to synthesize BaSnO3 nanomaterials with controlled stoichiometry and doping.

Lanthanum containing barium stannate nanoparticles synthesized by cetyltriammonium bromide assisted wet chemistry route for application in perovskite solar cell

Abstract In this paper, we report comparative photovoltaic performance of cetyltriammonium bromide assisted wet chemical route synthesized Ba0.94La 0.06SnO3 and sol-gel synthesized TiO2 nanoparticles using CH3NH3SnCl3 as absorber and NiO as hole transport layer. The X-ray diffraction patterns of Ba0.94La 0.06SnO3, TiO2 and NiO nanoparticles showed the formation of cubic, tetragonal and cubic phases, respectively with average crystallite size ∼ 25 nm. The X-ray diffraction pattern of CH3NH3SnCl3 nanoparticles exhibited the formation of monoclinic phase, with average crystallite size ∼ 5 nm. The band gap values of Ba0.94La 0.06SnO3, TiO2, NiO and CH3NH3SnCl3 nanoparticles are estimated as 3.6, 3.4, 3.5 and 2.8 eV, respectively. The silver contacts, which work as counter electrode, were thermally deposited, and device has been studied for power conversion efficiency under the illumination of ∼ 100 mW cm2.

Effect of iron doping on magnetic and electrical properties of BaSnO3 nanostructures

Structural, magnetic and dielectric properties for the synthesized Fe doped nano barium stannate (BaSnO3) are investigated intently. The nanocuboids, nanoparticles and nanorods of BaSnO3 (BSO) by the influence of Fe ions are seen. Raman measurements shows a blue shift (646 cm−1) for the doped system and the magnetic and electric properties are studied by VSM, dielectric and PE loop measurements. Well saturated ferromagnetism exhibited at room temperature with high saturation magnetization (23.025 m emu g−1) and coercivity (339.3 G) are observed for Fe (5 at.%) doped BaSnO3.

Initial Stages of Growth of Barium Zirconate Titanate and Barium Stannate Titanate Films on Single-Crystal Sapphire and Silicon Carbide

The initial stages of growth of barium zirconate titanate and barium stannate titanate ferroelectric films on single-crystal sapphire and silicon carbide are studied for the first time. The choice of substrates is dictated by the possibility of using such structures in ultra-high frequency devices. The growth of discontinuous BaZrxTi1–xO3 films is found to be mediated by the gas phase mass transport mechanism in the studied temperature range. For deposition of BaSnxTi1–xO3 films, the mechanism of mass transport switches at ~800°C from surface diffusion to gas phase diffusion; also, the films deposited on sapphire and silicon carbide have considerably different elemental composition. The formation of an intermediate SiO2 layer is noted on silicon carbide during the growth of oxide films on this substrate, its thickness depending on the deposition temperature.

Electrical and optical property measurement of nickel-doped barium stannate synthesized by modified solid state sintering

Mechanical mixing of precursors followed by sintering at 1350 °C treated for 2 h were performed to synthesize nickel-doped barium stannate BaSn1-x NixO3 with x = 0.05, 0.10 and 0.15. The phase formation of synthesized material was identified by X-ray Diffractogram (XRD), which confirms a cubic perovskite structure as major constituent. The crystallite size and plane of orientation were calculated from the diffraction pattern. The morphological behaviour was studied from SEM images, and the chemical constituents of the synthesized materials were identified from EDX spectra. Bond formation and M—O coordination of the synthesized materials were identified from FTIR absorption spectra corresponding to symmetric and asymmetric stretches of bonding. Optical properties of the sintered samples were measured by UV—V spectroscopy. The bandgap of the synthesized material was calculated from the spectrograph. The photoluminescence characteristics were studied from PL spectra. The nanocrystalline behaviour of the material was assessed from HRTEM images and SAED patterns. The electrical measurements in terms of dielectric and ferroelectric properties were measured for various concentrations of doped materials.

Effect of Europium (III) Oxide doping on the nanoscale ceramic Stannates(MSnO3) of Ca, Ba upon photo luminescence, catalytic degradation and anti-microbial activity – Green approach

The study of alkaline earth doped stannate ceramics of Barium and Calcium is being carried out to explore more on the phosphorescent applications. The present study is an energy and cost-efficient green approach towards the preparation of Europium (III) doped stannate of Calcium and Barium in the nano scale as it involves the biowaste of egg shell as a precursor for calcium carbonate and the plant extract of aloe vera as the reaction medium and a comparatively lower calcination temperature than reported so far. The structure, phase purity, surface morphology and applications in terms of photo luminescence, photo catalytic and anti-microbial activities have been investigated. The doping of alkaline earth metal of Europium in lower weight percentage (lesser than one) was carried out at lower processing temperatures than reported earlier. There was a phase transition in the case of barium stannate upon doping and there were observable changes in crystallite size, morphology and microstructure in the case of Stannates of Calcium and Barium. The results of photo luminescence study and the photo catalytic degradation of methylene blue dye were encouraging. The anti-microbial study in terms of toxicity of the doped samples in smaller dosages upon Pseudomonas aeruginosa, Staphylococcus aureus provided a new dimension to their application.

A strategy for obtaining high electrostrictive properties and its application in barium stannate titanate lead-free ferroelectrics

Recently electrostrictive effect in ferroelectrics has attracted much attention, since the electric field-induced strain based on such an effect possesses an ultra-low hysteresis, which is of special interest to both fundamental research and potential application in high-precision actuators. In this paper, we propose a strategy to obtain high electrostrictive properties in ABO3 perovskite structure BaTiO3 (BT)-based ferroelectric ceramics by means of doping. The doping element, amount, valence as well as position are specified according to this strategy. It is suggested that B-site Sn4+-doped BT, i.e., Ba(Ti1-xSnx)O3 (BTS), would possess superior electrostrictive properties. The structural evolution and electrical properties of BTS ferroelectric ceramics were investigated in detail in order to verify this deduction. Besides the ferroelectric-to-relaxor transition with respect to the increase of x from 0.06 to 0.11, expected and high electric field-induced strain (> 0.08% at 40 kV/cm) with a very ultra-low hysteresis (< 8%) is obtained in x = 0.10–0.11 compositions. High longitudinal electrostrictive coefficient Q33 ranges from to 0.0398 m4/C2 to 0.0515 m4/C2 accompanying with temperature- and composition-insensitive characteristics. These results not only prove the effectiveness of this strategy, but also pave a way to search for novel kinds of electrostrictive systems in ferroelectrics.

Highly performance of flexible transparent conductive Cu-based ZnO multilayer thin films via BS barrier layer

Highly performance of flexible transparent conductive Cu-based ZnO multilayer thin films are achieved by barrier layer of amorphous thin films based on barium stannate. The flexible multilayers exhibit high figure of merit (FoM) of 20.38 × 10−3 Ω−1 with the sheet resistance of 6.19 Ω/sq. and resistivity of 5.28 × 10−5 Ω cm, while the average optical transmittance is about 81.3% in the visible range. The FoM value is the highest among all the reported Cu-based transparent conductive thin films. The influence mechanism of BS barrier layers on electrical and optical properties of the multilayers is also proposed. Our results demonstrate that BS barrier layer is an effective way in tuning/improving the optical and electrical performances in the Cu-based ZnO multilayer thin films.

Bifacial Modified Charge Transport Materials for Highly Efficient and Stable Inverted Perovskite Solar Cells.

Significant efforts have been devoted to enhancing both the performance and long-term stability of lead halide perovskite solar cells (PSCs) to promote their practical application. In this context, a self-assembled monolayer composed of a dye molecule is demonstrated for the first time to be efficient in passivating the surface of the hole transport layer, NiO x, in the p-i-n PSCs through multiple functions, including the minimization of energy-level offset, reducing surface trap states, and enhancing wetting between NiO x and perovskite layers coupled with increasing perovskite crystallinity. Consequently, the dye monolayer has sufficiently improved the hole extraction efficiency and suppressed the charge recombination, validated by steady and transient photoluminescence measurements and the electrochemical impedance analysis. Concurrently, a mixed layer of BaSnO3 nanoparticles and [6,6]-phenyl-C61-butyric acid methyl (PCBM) (barium stannate (BSO)/PCBM) was exploited as an efficient electron transport layer, resulting in superior electron transport properties and correspondingly excellent device stability. By incorporating these bifacial modifications, the device performance of the inverted PSC was propelled to 16.2%, compared with 14.0% for that without any interfacial and compositional engineering. Benefiting from the excellent crystallinity of the perovskite through dye passivation and the blocking of moisture, oxygen, and ion migration by using the hybrid BSO/PCBM layer, over 90% of the initial power conversion efficiency has been preserved for the device after exposure to ambient air for 650 h.

Roles of Point Defects in Thermal Transport in Perovskite Barium Stannate

Perovskite barium stannate (BaSnO3) is a promising candidate that can be used as transparent conducting oxide in optoelectronic devices and as the channel material in high-mobility oxide electronics. In this work, we calculate the lattice thermal conductivity and investigate the impact of point defects on thermal transport in BaSnO3 based on the phonon Boltzmann transport equations with interatomic force constants from first-principles calculations. In pristine BaSnO3, we find the contribution of acoustic phonons to thermal transport accounts for 54% at 300 K and the rest is attributed to the lower-frequency (27.5–50 THz) optical modes with relatively high group velocity. We show oxygen vacancies and impurities can cause noticeable reduction in thermal conductivity of BaSnO3, but the corresponding mechanisms differ in terms of scattering rates on different phonon modes. The thermal conductivity reduction due to oxygen vacancies at 300 K is mainly caused by the increased scattering of the acoustic phonons and the low-frequency optical phonons. Lanthanum and potassium impurities mainly increase the scattering of acoustic phonons, but antimony impurity lowers the thermal conductivity by increasing the scattering rate of dominant phonons, including both the acoustic modes and the low-frequency optical modes. The results and findings facilitate us to better understand the thermal transport mechanisms of perovskite oxides with an emphasis on the impact of oxygen vacancies and impurities on the thermal properties of BaSnO3.

Facile wet chemical synthesis of Er3+/Yb3+ co-doped BaSnO3 nano-crystallites for dye-sensitized solar cell application

We report synthesis of pure and rare earth ion Er3+ /Yb3+ co-doped barium stannate (BaSnO3) nano-crystallites by facile wet chemical route. The nano-crystallites at the Ba2+ lattice site substitution of 0.1 and Er/Yb ratio of 0.00, 0.11, 0.18 and 0.25 exhibited band gap of 3.64, 3.66, 3.67 and 3.68 eV, respectively. The electrical conductivity of the nano-crystallites was found to increase with increase in Er/ Yb content ratio. All samples revealed a broad emission peak between 380 and 400 nm at the excitation wavelength of 350 nm. The up-conversion emission intensity has been found to increase with Er3+ /Yb3+ content for the excitation wavelength of 980 nm. Further, the influence of the up-conversion behavior on the photovoltaic performance of dye-sensitized solar cell has been investigated. The highest photon conversion efficiency of 4.2% was observed for the composition of Ba(Er/Yb: 0.25)SnO3 with JSC = 9.69 mA/cm2, Voc = 0.63 V, FF = 0.690, which was about 40% increase in efficiency in comparison to pristine BaSnO3 (3.0%).

Varying the Composition of Ferroelectric Films during Ion-Plasma Sputtering: Simulation and Experiment

Varying the elemental composition of ferroelectric thin films of barium strontium titanate, barium zirconate titanate, and barium stannate titanate solid solutions obtained by ion-plasma sputtering of ceramic targets at different pressures of the working gas is studied through simulation and experimentally. The experimental results are interpreted based on statistical simulation of the transport processes for fluxes of sputtered Ba, Sr, Sn, Zr, and Ti atoms in a gas medium. It is shown that the simulation results describe variations in the elemental composition satisfactorily (within 5%) in a wide range of working gas pressures. Theoretical and experimental studies enable us to choose the optimum values of technological parameters for obtaining ferroelectric thin films with specified elemental compositions that determine their electrophysical properties.

Origins of n -type doping difficulties in perovskite stannates

Materials that are simultaneously transparent and electrically conductive play a key role in optoelectronic devices. Barium stannate has recently come to the forefront as a promising new transparent conductor, but its conductivity has been difficult to control. The authors have performed computational studies to determine the mechanisms that limit doping. They find that atomic-scale defects, such as vacancies in the crystal lattice, are responsible, but their formation can be controlled by tailoring the growth conditions. The authors also investigated related materials, such as strontium stannate and calcium stannate, which are transparent even in the ultraviolet. Calcium stannate is found to always be insulating, but guidelines are provided for maximizing the conductivity of the strontium compound.

Behavior of lanthanum containing barium stannate nanoparticles synthesized by cetyltriammonium bromide assisted wet chemistry route

In present study, we report dielectric, ferroelectric and pyroelectric behavior of pristine and La3+ containing barium stannate nanoparticles synthesized via wet chemical route involving cetyltriammonium bromide assisted thermal decomposition of binary precursors. The X-ray diffraction patterns of pristine and La3+ (2, 4 and 6 at%) doped BaSnO3 nanoparticles showed the formation of cubic perovskite phase. On substitution of Ba2+ lattice sites by La3+ at the La content of 6 at%, the sample exhibited fourfold increase in conductivity in comparison to pristine BaSnO3. Polarization hysteresis (P-E) curves of La containing barium stannate nanoparticles showed anti-ferroelectric behavior. The pyroelectric coefficient of pristine and La (2, 4 and 6 at%) containing BaSnO3 nanoparticles at 473 K were found to be 7.8, 11.6, 14.1 and 17.2 μCm−2K−1, respectively. Further, the responsivity and detectivity values were higher in comparison to the materials, such as AlN, GaN, CdS and ZnO.

Structural properties of barium stannate

BaSnO3 has attracted attention as a transparent conducting oxide with high room temperature carrier mobility. We report a series of measurements that were carried out to assess the structure of BaSnO3 over a variety of length scales. Measurements included single crystal neutron and x-ray diffraction, Rietveld and pair distribution analysis of neutron powder diffraction, Raman scattering, and high-pressure x-ray diffraction. Results from the various diffraction probes indicate that both the long-range and local structures are consistent with the cubic symmetry. The diffraction data under pressure was consistent with a robustly cubic phase up to 48.9 GPa, which is supported by density functional calculations. Additionally, transverse phonon velocities were determined from measured dispersion of the transverse acoustic phonon branches, the results of which are in good agreement with previous theoretical estimates and ultrasound measurements.

Cetyltriammonium Bromide Assisted Synthesis of Lanthanum Containing Barium Stannate Nanoparticles for Application in Dye Sensitized Solar Cells

In present work, correlation of structural and optical behavior of pristine and lanthanum containing barium stannate nanoparticles (synthesized via cetyltriammonium bromide (CTAB) assisted facile wet chemical route), and its effect on photovoltaic properties of dye‐sensitized solar cell are reported. Thermo‐gravimetric analysis of the dried compound presumably BaSn(OH)6, leads to the formation of BaSnO3 nanoparticles through three endothermic decomposition processes, via liberation of one mole of water in each step, together with removal of remaining CTAB in initial cycle. The X‐ray diffraction patterns reveal that substitution of Ba2+ lattice sites by La3+ (upto ≈6 at.%), the lattice retains its cubic Pm3m symmetry, however, unit cell contracts. The dye sensitized solar cells are fabricated using pristine and La‐ containing BaSnO3 as photo anode; platinum coated FTO as counter electrode, N719 dye as sensitizer and I−/I3− as electrolyte. These show the highest power conversion efficiency (≈9.2%) at the La content of 6 at.% which is about threefold increase in efficiency in comparison to pristine BaSnO3. The electron transport properties of these DSSC devices are investigated by electro chemical impedance spectroscopy.

Tunable Optical Behaviour and Room Temperature Ferromagnetism of Cobalt-Doped BaSnO3 Nanostructures

In this work, the effect of Co doping on the structural, vibrational, morphological, optical and magnetic behaviour of BaSnO3 nanostructures is reported. Pure and Co (1,3, and 5%)-doped barium stannate (BSO) nanostructures were prepared by conventional hydrothermal technique followed by calcination at 900 °C for 5 h. The single crystalline cubic phase was identified by XRD analysis and structural distortions associated with Co doping were evidenced by variation in microstarin and crystallite size. FTIR and Raman studies further confirm the structural quality of the prepared samples. FESEM analysis revealed the mixed morphology of prepared samples, and the chemical compositions of all the samples were analysed using EDAX studies. The absorption studies revealed the incorporation of dopant ions and their effect on the bandgap subsequently in samples. The presence of defects and paramagnetic centres in the samples were confirmed by PL and EPR analyses. Magnetization studies demonstrated that pure BSO exhibits characteristic diamagnetism at room temperature and the addition of Co into Ba–Sn–O lattice drives the F-centre exchange interactions which results in the ferromagnetic behaviour. Hence, the occurrence of diamagnetic to ferromagnetic transition at room temperature with addition of Co as a dopant was identified.

Начальные стадии роста пленок цирконата-титаната бария и станната-титаната бария на монокристаллических подложках сапфира и карбида кремния

AbstractThe initial stages of growth of barium zirconate titanate and barium stannate titanate ferroelectric films on single-crystal sapphire and silicon carbide are studied for the first time. The choice of substrates is dictated by the possibility of using such structures in ultra-high frequency devices. The growth of discontinuous BaZr_ x Ti_1– x O_3 films is found to be mediated by the gas phase mass transport mechanism in the studied temperature range. For deposition of BaSn_ x Ti_1– x O_3 films, the mechanism of mass transport switches at ~800°C from surface diffusion to gas phase diffusion; also, the films deposited on sapphire and silicon carbide have considerably different elemental composition. The formation of an intermediate SiO_2 layer is noted on silicon carbide during the growth of oxide films on this substrate, its thickness depending on the deposition temperature.

CO and H2 oxidation over Pt/BaSnO3 catalysts

This work reports the results of the studies on oxidation of carbon monoxide and H2 over Pt supported on barium stannate (BaSnO3—perovskite type oxide). The composition and properties of Pt/BaSnO3 catalysts were characterized by X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (TOF–SIMS), H2 and CO chemisorption, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM–EDS) and tested in the reactions of carbon monoxide and hydrogen oxidation. It was stated that platinum strongly interacts with BaSnO3. The catalytic activity and adsorption properties of Pt/BaSnO3 catalysts are determined by these interactions. The presence of different species (which generally can be labelled as [(Pt)BaSnO3]) resulting from platinum and BaSnO3 chemical interaction was found by the TOF–SIMS on surface of Pt/BaSnO3 catalysts. The mechanism of CO and H2 oxidation over Pt/BaSnO3 catalysts was discussed in the light of strong interactions between Pt and BaSnO3.