Perovskite BaSnO3 Research Articles

Enhanced photocatalytic performances of highly efficient perovskite BaSnO3 nanorods decorated by CuMn2O4 nanoparticles

We report the fabrication of perovskite BaSnO3 nanorods decorated by CuMn2O4 nanoparticles by hydrothermal approach and their application as highly efficient for Ciprofloxacin (CIP) degradation under visible light illumination. The TEM image indicated the formation of BaSnO3 nanorods with average diameters and lengths of 50–80 nm and 0.5 µm decorated uniformly with CuMn2O4 NPs in the range of 10–20 nm. XRD revealed that the BaSnO3 nanorods with the formation of cubic perovskite structure and the spinel structure of CuMn2O4 with highly crystalline have been constructed. The results indicated that incorporating CuMn2O4 enhanced the photocatalytic performance of BaSnO3 nanorods. Overall the synthesized CuMn2O4/BaSnO3 nanocomposites, 15 % CuMn2O4/BaSnO3 nanocomposite, exhibited the highest photocatalytic ability of 100 % and constant rate of 0.0192 min−1 within 40 min. The photocatalytic ability of 15 % CuMn2O4/BaSnO3 nanocomposite was 4 and 2.2 times larger than that of bare CuMn2O4 and BaSnO3 nanorods. This was explained by the effective charge separation at the heterojunction CuMn2O4/BaSnO3 interface and the low recombination rate in charge carriers. The photocurrent and photoluminescence responses were utilized to verify the photocatalytic performance of CuMn2O4/BaSnO3 photocatalyst. The synthesized CuMn2O4/BaSnO3 nanocomposite with superb photocatalytic performance can be a promising candidate for detoxifying the organic compounds from industrial and domestic wastewater.

New nonmagnetic aliovalent dopants (Li+, Cu2+, In3+ and Ti4+): Optical and strong intrinsic room temperature ferromagnetism of perovskite BaSnO3

Nonmagnetic Li+, Cu2+, In3+ and Ti4+ ions were employed to induce robust room temperature ferromagnetism in perovskite BaSnO3 for advanced spintronics applications. New BaSn0.96M0.04O3 (M = Li+, Cu2+, In3+ and Ti4+) compositions were synthesized by modified Pechini method. In all compositions, single phase of cubic BaSnO3 was detected in the XRD patterns without any impurities. The FTIR spectra displayed the distinctive vibrational absorption band of BaSnO3 and verified the absence of any impurities. The SEM images evidently showed a decrement of grain size alongside morphological changes for doped BaSnO3 compositions compared to the pure one. The band gap energy of BaSnO3 was considerably influenced by the incorporation of Li+, Cu2+, In3+ and Ti4+ dopants. BaSn0.96Cu0.04O3 sample exhibited the highest refractive index value and the minimum value was obtained for BaSn0.96Ti0.04O3. Remarkably, at equal concentration two of the used nonmagnetic elements showed the ability to induce room temperature ferromagnetism in BaSnO3 lattice. Herein, BaSn0.96Cu0.04O3 exhibits a robust and symmetrical ferromagnetic hysteresis loop with complete saturation magnetization (Ms) of 0.158 emu/g and coercivity (Hc) of 42 Oe. BaSn0.96Ti0.04O3 composition revealed a ferromagnetic behavior within magnetic field of± 5000 Oe and the trend was reversed for higher values to show a diamagnetic performance. The interaction between the 3d orbitals of Cu2+ (3d9) or Ti4+ (d0) with the trapped electrons in the oxygen vacancies encourage a ferromagnetic coupling in BaSnO3 structure. The outer shell orbitals of Cu2+ and Ti4+ dopants and the oxygen vacancies seem to play a significant role in the magnetic properties.

Phonon decay in BaSnO3 perovskite

Time-domain coherent Raman techniques have been utilized to selectively measure ultrafast decay rates of optical phonons in cubic BaSnO3 perovskite. Measurements were made within a 350–1300 cm−1 frequency range with time and equivalent spectral resolution of ∼120 fs and less than 0.1 cm−1, respectively. The phonon mode damping rates are found to be within 1.27–1.59 ps−1 at room temperature, indicating that the homogeneously broadened Raman linewidths are within 6.7–8.4 cm−1. Phonon decay mechanisms are being discussed within the framework of parametric phonon interactions due to lattice anharmonicity. Characteristics of the Raman active modes are essential in understanding the limiting factors for achieving high carrier mobility in device applications of the material.

The effect of chalcogens-doped with dilation strain on the electronic, optic, and thermoelectric properties of perovskite BaSnO3 compound

The effect of chalcogens-doped with dilation strain on the electronic, optic, and thermoelectric properties of perovskite BaSnO3 compound

Optical measurements and Burstein Moss effect in optical properties of Nb-doped BaSnO3 perovskite

The research for novel transparent electrodes has gained popularity due to the low abundance and the high cost of Indium. In this paper, we used first-principles calculations employing density functional theory with the exchange-correlation energy functional approximation Generalized Gradient Approximation to analyze the optical, structural, and electronic properties of Niobium doped Barium tin oxide with 12.5%, 6.25%, and 3.125% of doping. The electronic structure calculations show an indirect bandgap of Barium tin oxide. Niobium induces extrinsic donor energy states around the bottom of the conduction band giving rise to an improvement in the electrical conductivity in the system. The Fermi level shifts upward to the conduction band, a typical characteristic of an n-type semiconductor. Burstein Moss effect was found in the optical measurements for the dope systems, leading to an increase in the apparent bandgap. A diminution in the absorption coefficient in the UV–visible range of the light was presented. These characteristics suggest that Nb-doped BaSnO3 is a promising transparent conducting oxide and can be useful for optoelectronic applications.

Detection of acetone via exhaling human breath for regular monitoring of diabetes by low-cost sensing device based on perovskite BaSnO3 nanorods

This study aims to determine whether the analysis of volatile organic compounds (VOCs) in exhaled breath can be used as a non-invasive monitoring tool for diabetes patients. Here, we are reporting perovskite BaSnO3 based quick responsive and highly sensitive acetone biosensor for the sensing of low concentration acetone in the human breath. The BaSnO3 nanomaterial has been prepared by the sol-gel assisted hydrothermal method and confirmed by various characterization tools such as X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), UV–Visible absorption spectroscopy and Dynamic light scattering (DLS) analysis. XRD result reveals the cubic polycrystalline nature with space group of Fm-3 m of BaSnO3 with the average crystallite size of 24.197 nm and induced strain of 1.441 × 10-4. From the X-ray Photoelectron Spectroscopy (XPS) binding energy separation between Barium and Tin doublets are found to be 15.351 eV and 8.426 eV, which confirms the presence of Ba2+ and Sn4+ states respectively. For the exhale human breath level acetone of 1 ppm, the fabricated device shows the sensor response of 6.795 along with the fast performance with 3.325 s response time. The highest sensing response was found 45.850 for 50 ppm of acetone at 80 °C operating temperature and such sensing device shows the excellent linearity between blood glucose level and sensor response.

Quantitative Determination of Native Point‐Defect Concentrations at the ppm Level in Un‐Doped BaSnO3 Thin Films

AbstractThe high‐mobility, wide‐bandgap perovskite oxide BaSnO3 is taken as a model system to demonstrate that the native point defects present in un‐doped, epitaxial thin films grown by hybrid molecular beam epitaxy can be identified and their concentrations at the ppm level determined quantitatively. An elevated‐temperature, multi‐faceted approach is shown to be necessary: oxygen tracer diffusion experiments with secondary ion mass spectrometry analysis; molecular dynamics simulations of oxygen‐vacancy diffusion; electronic conductivity studies as a function of oxygen activity and temperature; and Hall‐effect measurements. The results indicate that the oxygen‐vacancy concentration cannot be lowered below 1017.3 cm−3 because of a background level of barium vacancies (of this concentration), introduced during film growth. The multi‐faceted approach also yields the electron mobility over a wide temperature range, coefficients of oxygen surface exchange and oxygen‐vacancy diffusion, and the reduction enthalpy. The consequences of the results for the lowest electron concentration achievable in BaSnO3 samples, for the ease of oxide reduction and for the stability of reduced films with respect to oxidation, are discussed.

High-Mobility Field-Effect Transistor Using 2-Dimensional Electron Gas at the LaScO3/BaSnO3 Interface

A 2-dimensional electron gas (2DEG) system with high mobility was discovered at the interface of two perovskite oxides: a polar orthorhombic perovskite LaScO3 and a nonpolar cubic perovskite BaSnO3. Upon depositing the LaScO3 film on the BaSnO3 film, we measured the conductance enhancement and the resulting 2DEG density (n2D). Comparing the results with the previously reported LaInO3/BaSnO3 polar interface, we applied the “interface polarization” model to the LaScO3/BaSnO3 system, in which the polarization exists only over four pseudocubic unit cells in LaScO3 from the interface and vanishes afterward like the LaInO3/BaSnO3 interface. Based on the calculations of the self-consistent Poisson–Schrödinger equations, the LaScO3 thickness dependence of n2D of the LaScO3/BaSnO3 heterointerface is consistent with this model. Furthermore, a single subband in the quantum well is predicted. By use of the conductive interface and the LaScO3 as a gate dielectric, a 2DEG transistor composed of only perovskite oxides with high field-effect mobility (μFE) close to 100 cm2 V–1 s–1 is demonstrated.

Tunning tin-based perovskite as an electrolyte for semiconductor protonic fuel cells

The use of ceramic semiconductors to serve as an efficient proton conductor is an evolving approach in the novel emerging field of semiconductor protonic fuel cells (SPFCs). One of the most critical challenges in SPFCs is to design a sufficient proton-conductivity of 0.1 S cm−1 below <600 °C. Here we report to tune the perovskite BaSnO3 (BSO), a semiconductor single-phase material, to be applied as a proton-conducting electrolyte for SPFC. It was found that the oxygen vacancies play a vital role to promote proton transport while the electronic short-circuiting issue of BSO semiconductor has been justified by the Schottky junction mechanism at the anode/electrolyte interface. We have demonstrated a SPFC device to deliver a maximum power density of 843 mW cm−2 with an ionic conductivity of 0.23 S cm−1 for BSO at 550 °C. The oxygen vacancy formation by increasing the annealing temperature helps to understand the proton transport mechanism in BSO and such novel low-temperature SPFC (LT-SPFC).

Tuning two-dimensional electron and hole gases at LaInO3/BaSnO3 interfaces by polar distortions, termination, and thickness

Two-dimensional electron gases (2DEG), arising due to quantum confinement at interfaces between transparent conducting oxides, have received tremendous attention in view of electronic applications. Here, we explore the potential of interfaces formed by two lattice-matched wide-gap oxides of emerging interest, i.e., the polar, orthorhombic perovskite LaInO3 and the nonpolar, cubic perovskite BaSnO3, employing first-principles approaches. We find that the polar discontinuity at the interface is mainly compensated by electronic relaxation through charge transfer from the LaInO3 to the BaSnO3 side. This leads to the formation of a 2DEG hosted by the highly dispersive Sn-s-derived conduction band and a 2D hole gas of O-p character, strongly localized inside LaInO3. We rationalize how polar distortions, termination, thickness, and dimensionality of the system (periodic or non-periodic) can be exploited in view of tailoring the 2DEG characteristics, and why this material is superior to the most studied prototype LaAlO3/SrTiO3.

The effect of Sr and Sb co-doping on structural, morphological and thermoelectric properties of BaSnO3 perovskite material

BaSnO3 (BSO) is one of the promising perovskite materials for high temperature thermoelectric applications. The pure BSO, Sr and Sb co-doped BSO materials were prepared by the polymerization complex method and annealed at 1473 K. The X-ray diffraction patterns confirmed the cubic structure of pure BSO and Sr-Sb co-doped BSO. The addition of Sr and Sb changed the morphology of BSO from microstructures to the layered and polygonal shaped nanostructure. The valence states of each elements of the samples were confirmed by the X-ray photoelectron spectroscopy. The addition of Sb5+ atom in Sn4+ site modified the electronic band structure thereby enhanced electrical conductivity. The highest power factor of 25.3 μW/(m K2) was achieved for the SrSb5(Sr: 5 mM and Sb: 5 mM in the polymerization complex method) at 578 K. The reduced thermal conductivity and increased power factor in SrSb5 resulted in the higher figure of merit of 2.1 × 10−3 at 578 K.

Dopant Segregation Inside and Outside Dislocation Cores in Perovskite BaSnO3 and Reconstruction of the Local Atomic and Electronic Structures.

Distinct dopant behaviors inside and outside dislocation cores are identified by atomic-resolution electron microscopy in perovskite BaSnO3 with considerable consequences on local atomic and electronic structures. Driven by elastic strain, when A-site designated La dopants segregate near a dislocation core, the dopant atoms accumulate at the Ba sites in compressively strained regions. This triggers formation of Ba vacancies adjacent to the core atomic sites resulting in reconstruction of the core. Notwithstanding the presence of extremely large tensile strain fields, when La atoms segregate inside the dislocation core, they become B-site dopants, replacing Sn atoms and compensating the positive charge of the core oxygen vacancies. Electron energy-loss spectroscopy shows that the local electronic structure of these dislocations changes dramatically due to segregation of the dopants inside and around the core ranging from formation of strong La-O hybridized electronic states near the conduction band minimum to insulator-to-metal transition.

Growth and characterization of crystalline BaSnO3 perovskite nanostructures and the influence of heavy Mn doping on its properties

Solid state reaction synthesis of BaSn1-xMnxO3 (x = 0.0–0.3) nanostructures is presented in this article. Heavy transition metal doping in powdered BaSnO3 is accomplished to investigate the structural, morphological, chemical and dielectric properties of synthesized samples. Single phase, cubic crystal formations are revealed from the structural properties. Transmission electron micrographs (TEM) display the formation of polygonal discs with nanoscale (~50 nm) dimensions. Elemental composition of the synthesized samples has been confirmed from the x-ray photoelectron spectroscopy (XPS). Optical properties demonstrate the pristine BaSnO3 as an ultraviolet active material with a band gap of 3.2 eV. The enhancement in visible light active mode is achieved via band gap tuning by proportional Mn-doping in the parent material.

Electron transport of perovskite oxide BaSnO3 on (110) DyScO3 substrate with channel-recess for ferroelectric field effect transistors

We report an electron transport study of an La-doped perovskite oxide BaSnO3 thin film grown by molecular beam epitaxy on (110) DyScO3 as a function of electron concentration, by etching the film step-by-step with nanometer precision. Inductively coupled plasma-reactive ion etching with BCl3/Ar plasma is used for etching depth control. The local doping and electron density are experimentally determined after each etching step. The results show that the electron mobility is dominated by threading dislocations if the electron concentration is below 7.8 × 1019 cm−3, while ionized impurities and phonon scattering become more dominant at electron concentrations greater than 1.2 × 1020 cm−3. The charging state of thread dislocations is estimated to be 6.2. Furthermore, using the etch process to control the electron concentration and channel thickness, a gate-recessed ferroelectric field effect transistor is fabricated with 10 nm HfO2 as a gate dielectric. The device exhibits a saturation current of 29.9 mA/mm with a current on/off ratio of Ion/Ioff = 8.3 × 108 and a ferroelectric polarization charge density of 1.9 × 1013 cm−2. Under the forward gate bias sweep, the device operates in the enhancement mode with a threshold voltage of 3 V. Under the reverse gate sweeping bias, the device operates in the depletion mode with a threshold voltage of –1.5 V.

Metallic line defect in wide-bandgap transparent perovskite BaSnO3.

A line defect with metallic characteristics has been found in optically transparent BaSnO3 perovskite thin films. The distinct atomic structure of the defect core, composed of Sn and O atoms, was visualized by atomic-resolution scanning transmission electron microscopy (STEM). When doped with La, dopants that replace Ba atoms preferentially segregate to specific crystallographic sites adjacent to the line defect. The electronic structure of the line defect probed in STEM with electron energy-loss spectroscopy was supported by ab initio theory, which indicates the presence of Fermi level-crossing electronic bands that originate from defect core atoms. These metallic line defects also act as electron sinks attracting additional negative charges in these wide-bandgap BaSnO3 films.

Simultaneous electrochemical determination of nitrofurantoin and nifedipine with assistance of needle-shaped perovskite structure: barium stannate fabricated glassy carbon electrode.

A needle-shaped perovskite, barium stannate (BaSnO3), was synthesized via a co-precipitation technique for the simultaneous electrochemical determination of antibiotic drug nitrofurantoin (NFTO) and pericardial drug nifedipine (NFP). The spectroscopic and microscopic result confirms that as-prepared BaSnO3 particles formed with desired crystalline nature, functional group, pore size, pore diameter, and fine needle-like morphology. The simultaneous electrochemical detection of thetwo pharmaceutical compounds was examined via cyclic voltammetry (CV) and differential pulse voltammetry (DPV) technique using BaSnO3-modified glassy carbon electrode (BaSnO3/GCE) at a potential range from +0.4 to - 1.2V. The discrete and simultaneous detection of NFTO and NFP at the BaSnO3 sensor exhibits higher catalytic activity in terms of cathodic current and cathodic potential compared to bare GCE. DPV results of theBaSnO3 sensor provide improvedlinear ranges and limits of detection for NFTO (0.01-42.65µM; 42.65-557.65μM, 0.062μM, respectively) and NFP (0.01-697.65μM, 0.0168μM, respectively). Besides, the BaSnO3-fabricated sensor exhibits goodsensitivity, reproducibility, and repeatability. Themodified electrode shows excellent recoveries of NFTO (97.0-100.7%) and NFP (98.7-101.3%) in plasma, urine, and milk samples with an acceptable relative standard deviation (RSD) of 1.6-4.8%. Graphical abstract Needle-shaped BaSnO3 perovskite material for simultaneous electrochemical sensing of pharmaceutical drugs.

Promoting the surface active sites of defect BaSnO3 perovskite with BaBr2 for the oxidative coupling of methane

In this work, to develop better OCM catalysts, especially with improved ethylene selectivity, the promotional effects of BaBr2 on defect BaSnO3 has been investigated by changing the BaBr2/BaSnO3 molar ratio. XRD and Raman have substantiated that BaBr2 and BaSnO3 co-exists in all the BaBr2-modified catalysts. Compared with pure defect BaSnO3, all the modified catalysts exhibit significantly improved OCM performance, particularly with extremely high ethylene selectivity. Electrical conductivity measurement have proven that defect BaSnO3 is a p-type semi-conductor favouring OCM reaction, whose surface possesses abundant vacancies. O2-TPD, CO2-TPD and electrical conductivity dependence on O2 partial pressure results have indicated that BaBr2 addition can enhance the surface oxygen vacancy concentration of BaSnO3, which facilitates the conversion of surface lattice O2− into OCM reactive oxygen sites, such as O22− and O2- anions. At the same time, a larger amount of moderate strength basic sites have been formed. EPR, in situ Raman and XPS results have demonstrated that the quantities of these active oxygen sites can be evidently improved by BaBr2 addition. More importantly, a type of new O2δ- (0 <δ < 1) sites beneficial to OCM reaction have also been formed. Notably, XPS results have revealed that the amount of O22− sites, which can directly convert CH4 into ethylene through carbene intermediates, has been remarkably increased due to the interaction between BaBr2 and BaSnO3. As a consequence, the OCM reaction performance, especially ethylene selectivity and yield on the BaBr2-modified BaSnO3, has been significantly improved.

Hydrogen Evolution Reaction of BaSnO3- δ Thin Film on p-Si

Oxide perovskites are proposed as photoelectrodes for the hydrogen evolution reaction(HER) in alkaline solutions. The cubic perovskite BaSnO3 can be used as a photoelectrode due to the edge position of conduction band, which is lower than the reduction potential. However, since it has a wide band gap of 3.1 eV, it is limited to use energy of a long wavelength including visible light. In this research, we investigated photoelectrochemical characteristics of BaSnO3 thin film deposited by Pulsed laser deposition(PLD) with promoting oxygen vacancy. The HER performance was enhanced due to band gap adjusted oxygen vacancy concentration. Furthermore, Electrochemical Impedance Spectroscopy(EIS) was measured to confirm surface charge resistance and charge transport. Thus, this study introduces that BaSnO3-δ/p-Si can be an efficient electrode for HER.

Influence of antimony on the structural, electronic, mechanical, and anisotropic properties of cubic barium stannate

Throughout this study, we have investigated Sb doping’s effects on the physical metallurgy of perovskite BaSnO3 by employing the first-principles calculations based on the density functional theory (DFT). We observed an increasing trend of lattice constants with an increasing doping concentration of Sb on perovskite BaSnO3. The calculated formation enthalpy and elastic constants ensured the structural stability of our system even under varied doping of Sb. Our band structure calculations suggested that it would be possible to tune the band structure of BaSnO3 by partially substituting Sb at the Sn-site, which reduced the band gap at low doping levels and transformed the compound from semiconducting to metallic at Sb ≥ 12.5%. The mechanical properties exhibited the prominent effects of Sb doping. In addition, the anisotropy of our system was significantly dependent on the elastic constant Cij and varied as the doping concentration of Sb is increased. Therefore, our simulation outputs clearly illustrated the importance of taking into account the Sb doping influence on the physical properties of BaSnO3 perovskite material.

Noncorrosive necking treatment of the mesoporous BaSnO3 photoanode for quantum dot-sensitized solar cells

The perovskite structure BaSnO3 is regarded as a promising photoanode material, and an effective necking treatment strategy is necessary for the electrical connectivity of mesoporous BaSnO3 photoanode-based solar cells. The often-adopted necking strategy involves the treatment in TiCl4 solution with low pH, which can lead to the leaching of barium cations from BaSnO3 and impair the effect of the necking treatment. To address this issue, we report herein a novel noncorrosive necking strategy based on the common ion effect. The strategy involved treating the mesoporous BaSnO3 photoanode with a mixture solution of TiCl4 and BaCl2. Compared with the common TiCl4 necking treatment, the treatment with TiCl4 and BaCl2 mixture solution negligibly affected the formation of the TiO2 overlayer on the surface of BaSnO3 particles, but it maintained the crystallinity of the BaSnO3 particles. The TiCl4 and BaCl2 mixture solution treated BaSnO3 photoanodes were assembled into CdSe/CdS co-sensitized quantum dot-sensitized solar cells (QDSSCs), which showed ca. 37% increase in power conversion efficiency in comparison with the TiCl4 treated photoanode. The charge extraction, electrochemical impedance spectroscopy, and intensity-modulated voltage/photocurrent spectroscopy measurements showed that the QDSSCs fabricated from the TiCl4 and BaCl2 mixture solution treated BaSnO3 photoanode contained fewer trap states and exhibited less charge recombination and longer electron lifetime than those based on the common TiCl4 treated photoanodes, demonstrating the effectiveness of the noncorrosive necking treatment.