Barium Stannate Research Articles

Unraveling the thickness-dependent high photoconductivity in BaSnO3 thin films: insights from ultrafast charge carrier dynamics

Abstract Barium stannate, a perovskite-structured semiconductor, is gaining significant attention for its potential in high-performance UV photodetectors and optoelectronic applications. This study investigated the photo-response of epitaxial BaSnO3 (BSO) thin films grown using pulsed laser deposition. Our findings revealed an exceptionally high photo-response in BSO films having thicknesses (90, 270, and 360 nm). Detailed optical analyses were conducted to elucidate the photoconductive response’s mechanisms, including photoluminescence (PL), time-resolved PL, and the ultrafast transient spectroscopy. Notably, ultrafast transient spectroscopy was employed for the first time on this material. Leveraging BSO’s wide bandgap (3.4 eV), photoconductivity measurements in the UV range showed a peak responsivity of 5 A W−1 at 5 V with a 360 nm film and a response time of 470 ms. The transient spectroscopy reveals the thickness-dependent carrier dynamics, such as carrier relaxation, carrier trapping in mid-gap states, and recombination. Specifically, observed trapping times were approximately 6 ps for 360 nm thickness, 26 ps for 270 nm thickness, and 59 ps for 90 nm thickness of BSO thin film. This research enhances the understanding of the photoconductive behavior of barium stannate thin films and lays the groundwork for optimizing BSO-based UV-sensitive optoelectronic devices.

Neuromorphic synaptic applications of oxygen-deficient BaSnO3 thin films

Cubic barium stannate (BaSnO3) has emerged as a promising platform for optoelectronic devices due to its remarkable room-temperature electron mobility, high transparency, excellent thermal stability, and flexible doping control. In this work, a photonic synaptic device—an image sensor integrating memory and processing—was proposed based on the persistent photoconductivity of oxygen-deficient BaSnO3 thin films. The device demonstrated a light-tunable response, allowing it to replicate key functions of biological synapses. Importantly, this device can be utilized as a reservoir layer in a reservoir computing system, achieving a recognition accuracy of over 90% when identifying handwritten digit images. This work underscores the potential of BaSnO3 for retinomorphic computing applications.

Enhanced H2S Gas Sensing Performance of SnO2/BaSnO3 Heterostructures

In this study, tin oxide (SnO2) nanofibers were fabricated using electrospinning technology and composited with barium stannate (BaSnO3) perovskite material to produce a heterojunction film. X-ray diffractions results showed SnO2 was oriented at 550 °C with 4 h of calcination, and BaSnO3 was oriented at 700 °C with 4 h of calcination. SnO2 nanofibers are average deposits on the substrate without any bulking and curling. By employing the “point-coat” process and observing with scanning electron microscopy, a SnO2/BaSnO3 heterojunction thin film was successfully synthesized. After the gas detection, the sensitivity difference of the SnO2/BaSnO3 had enhanced to 40 ∼ 60% in 10 ppm of H2S at different temperatures compared with pure SnO2, and SnO2/BaSnO3 had maintained at 75 ∼ 76% sensitivity in 10 ppm of H2S at 255 °C.

Epitaxial films and devices of transparent conducting oxides: La:BaSnO3

This paper reviews recent developments in materials science and device physics of high-quality epitaxial films of the transparent perovskite La-doped barium stannate, La:BaSnO3. It presents current efforts in the synthesis science of epitaxial La:BaSnO3 films for achieving reduced defect densities and high electron mobility at room temperature. We discuss the scattering mechanisms and the route toward engineering defect-free epitaxial La:BaSnO3 heterostructures. By combining chemical surface characterization and electronic transport studies, special emphasis is laid on the proper correlation between the transport properties and the electronic band structure of La:BaSnO3 films and heterostructures. For application purposes, interesting optical properties of La:BaSnO3 films are discussed. Finally, for their potential application in oxide electronics, an overview of current progress in the fabrication of La:BaSnO3-based thin-film field-effect transistors is presented together with recent progress in the fundamental realization of two-dimensional electron gases with high electron mobility in La:BaSnO3-based heterostructures. Future experimental studies to reveal the potential deployment of La:BaSnO3 films in optoelectronic and transparent electronics are also discussed.

The influence of the dopant concentration and sintering parameters on properties of antimony doped barium stannate ceramics

In this paper, the influence of antimony concentration and different sintering techniques on the structural, microstructural, and electrical properties of antimony-doped barium stannate, BaSn1-xSbxO3 (BSSO, x = 0.00, 0.04, 0.06, 0.08 and 0.10) was investigated. BSSO-based ceramic samples were obtained by conventional and spark plasma sintering. The XRD analysis confirmed the single-phase, cubic BaSnO3 lattice system in all conventionally sintered samples. Apart from the dominant cubic phase, the spark plasma sintering conditions led to the formation of a secondary phase, Ba2SnO4, in all samples. FESEM analysis revealed the presence of low angle grain boundaries (LAGBs) in BSSO samples with high antimony concentration (x = 0.08), independently of the sintering technique. However, the fraction of LAGBs is significantly higher in the BaSn0.92Sb0.08O3-SPS sample due to the simultaneous exposure of the conductive sample to the effects of high temperature and pressure during sintering process. These boundaries have low activation energy and allow free charge carrier transport through the grain boundary region. The high dopant concentration and the presence of large fraction of LAGBs in BaSn0.92Sb0.08O3-SPS sample reflected on its electrical properties through low and almost temperature-independent electrical resistivity in the temperature range of 25–150 °C.

Investigating the effect of Y3+/La3+ co-dopant on Ba site of BaSnO3 as an efficient photoanode for dye sensitized solar cell application

This study aims to improve the performance of barium stannate (PBS) based photoanode by co-doping with rare earth elements (Y3+ and La3+) and optimizing charge transport in the mesoporous TiO2 (meso-TiO2) as compact layer at the FTO interface. Employing Y3+ and La3+ dopant into BaSnO3 (YLB) at the FTO/meso-TiO2/YLB interface enhances light absorption and minimizes charge recombination. The resulting DSSC device, utilizing a meso-TiO2/YLB3 photoanode (PBS-3% of Y3+/La3+), achieves an efficiency of 3.79 %, with a high current density of 8.04 mA/cm2, a fill factor of 64.76 % and an open circuit voltage of 0.73 V. The synergistic effect of dopant and compact layer treatment purposefully improves photon and charge collection, enhancing overall device performance and reducing recombination at the interface. Consequently, the introduction of a compact layer-treated co-doped PBS photoanode emerges as a promising alternative for a charge transport layer in DSSC.

Fabrication of high performance BaSnO3/PVDF piezoelectric nanogenerator through high surface area BaSnO3 nanoparticle assisted β-phase stabilization of PVDF

Piezoelectric nanogenerators (PENGs) are becoming increasingly popular for energy generation and their use in smart electronics. In this study, a barium stannate (BaSnO3)-doped polyvinylidene fluoride (PVDF)-based PENG has been fabricated for the first time. The β-phase of PVDF was stabilized by optimizing the doping of BaSnO3 nanoparticles without the need for external electrical poling. The high surface area of the BaSnO3 nanoparticles promotes the nucleation of the polar β-phase in PVDF through electrostatic interaction. A low-cost solution casting method was used to prepare flexible BaSnO3/PVDF nanocomposite containing 5 wt% BaSnO3, which was then shaped and sandwiched between copper electrodes and protected with a thin PDMS layer to create the final PENG. The fabricated PENG can generate up to ∼41 V of voltage, ∼1.51 µA of current and ∼18.1 µW/cm2 of power density when ∼15.7 kPa pressure is applied by a human finger. The PENG can also charge capacitors, power up 16 LEDs in a series connection, and power other small electronics such as wristwatches, speakers, and calculators. Additionally, the PENG can activate the electrochromic material methyl viologen, which is commonly used in smart window applications.

Lithium doping's effects on the microstructural, dielectric, energy storage, optical and electrical properties of BaTi0.89Sn0.11O3 ceramics

The present study discusses the synthesis of lithium-doped barium stannate titanate BaTi0.89Sn0.11O3 (BTS11) using sol–gel synthesis route and explores the influence of the lithium content on their structural, morphological, ferroelectric, optical, and electrical properties. The phase of the sol–gel prepared samples with different atomic composition BaLixTi0.89Sn0.11O3(BLxTS11), with x = 0 %, 2 %, 4 %, 6 %, 8 and 10 %, was investigated using X-ray diffraction (XRD) revealing the formation of pure perovskite exhibiting lattice strain. Structural characterization was additionally conducted using Raman spectroscopy to detect structural and the chemical environment modifications caused Li incorporation. The doping induced variation also in the morphology and grain size of BLxTS11 pellets studied using SEM micrographs, which revealed evident grain size changes inversely proportional to the BLxTS11 lattice strain. The samples were then inspected for their ferroelectric properties. The maximum dielectric constant of all samples was observed at a temperature of around 45–50 °C. In addition, correlations between the chemical, structural, and morphological properties of the BLxTS11 ceramics and their energy storage capabilities were established. According to the P-E hysteresis behavior, BL6TS11 ceramic (x = 6 %) ferroelectric demonstrated the highest energy-storage capabilities, with a recoverable energy-storage density of 225 mJ/cm3 and an energy-storage efficiency of 60 %. The optical and electrical properties of the material were also investigated revealing a decrease in the band gap values and a significant increase of resistivity by Li doping.

Stable and efficient hydrogen evolution activity of tungsten-incorporated nanocrystalline perovskite BaSnO3 electrocatalyst

The increasing demand in energy consumption and alarming environmental concern is compelling to develop alternative renewable and clean energy sources. Hydrogen (H2) is identified as a potential candidate due to its abundance, high gravimetric energy density, and no carbon footprint. Presently, splitting of water is a highly promising method for sustainable hydrogen generation, and the key challenge is to develop a stable and high-performing electrocatalysts for H2 evolution reaction (HER) as a renewable energy source. Metal oxides are excellent alternative electrocatalysts to noble metals due to their cost effectiveness, tunability and abundance. Ternary perovskite barium stannate (BaSnO3) has been intensely explored for water splitting and electrocatalysis related applications. Tungsten (W) 1 % incorporated BaSnO3 synthesized by facile hydrogen peroxide route is explored as an electrocatalyst for HER activity in acidic medium for the first time. The pure and W-incorporated BaSnO3 exhibited promising HER activity with an overpotential value of 233 and 295 mV at 10 mA/cm2 with enhanced electrochemical surface area of 7.309 and 3.075 Fcm−2, respectively. A 12-hour stability test not only concluded the durability and performance of H2 evolution activity but also confirmed the enhanced initial current density for the W-incorporated BaSnO3 sample.

An ethylvanillin electrocatalytic sensor based on perovskite La3+-doped barium stannate nanorods

Herein, a series of La3+-doped BaSnO3 nanorods (Ba1-xLaxSnO3) were prepared by sol-gel method and were developed as electrochemical sensor for the electrochemical detection of ethylvanillin (EVA). The Ba1-xLaxSnO3 sensor exhibited better electrocatalytic detection performance than that of GCE and BaSnO3, which is ascribed to the enhancement of conductivity and active sites after the introduction of La3+. The optimized Ba0.995La0.005SnO3 sensor exhibited a linear range from 0.05 μM to 130 μM and a low limit of detection (LOD) of 8.6 nM. Mechanistic study demonstrated that the electrochemical oxidation process of EVA is involved the diffusion control process of two electrons and the same number of protons. Additionally, the proposed sensor for EVA demonstrated good anti-interference ability, repeatability (RSD ∼2.70 %), reproducibility (RSD ∼2.99 %), and stability (RSD ∼2.44 %). Moreover, the Ba0.995La0.005SnO3 sensor has good recoveries (100.4 %–102.4 %) for the detection of EVA in real milk powder extraction sample. The as-fabricated Ba0.995La0.005SnO3 sensor provide the possibility to detect the EVA in the real sample.

Transport properties of highly dense proton-conducting BaSn1−xInxO3−δ ceramics

Doped barium stannate belongs to the perovskite-structured complex oxides with proton transport capability. Such objects are of high interest in terms of their application in various protonic ceramic electrochemical cells. In the present work, In-doped barium stannate (BaSn1−xInxO3−δ, 0 ≤ x ≤ 0.4) materials were prepared and thoroughly characterized by structural, microstructural, and electrochemical techniques. The single-phase and high-dense ceramic materials were prepared by the conventional solid-state synthesis route over the entire doping range investigated. The chemical composition of these materials was found to be in close agreement with the nominal values, indicating no evaporation of Ba-, Sn-, or In-containing phases during sintering. The high-temperature electrochemical analysis showed that the ionic conductivity of BaSn1−xInxO3−δ gradually increases with increasing the In-content without reaching a concentration maximum, even for high dopant concentrations. The relatively high activation energy values indicate that this ionic conductivity is determined by oxygen-ionic transport, which, however, becomes predominantly protonic at reduced temperatures. The determination of bulk and grain boundary transport showed that both were improved with the In-doping. The possible reasons for these observations were discussed in detail in this work. Therefore, the obtained data are important for discovering the transport properties of stannates and their potential applications.

Zinc-modified barium stannate micro-rods: Investigating structural, morphological, and optical features

In the present study, we have synthesized pristine and Zn-doped (0.025, 0.05, 0.075, 0.10) barium stannate (BSO) micro-rods via the hydrothermal method. The prepared samples have been analyzed for their structural, optical, and morphological properties using X-ray diffraction technique (XRD), UV–Vis diffuse reflectance spectroscopy, field emission scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDX). Our Rietveld refinement examination of the XRD data verifies that the samples are single-phase, with a cubic crystal structure. Additionally, the lattice parameters determined align closely with the existing literature. Furthermore, the FE-SEM analysis unveiled the presence of well-defined rod-shaped structures accompanied by particle agglomeration across the surface. Further, the EDX analysis confirmed the presence of key elements, providing crucial insights into the material's chemical makeup. Especially noteworthy was the UV-DRS analysis, demonstrating a direct correlation between increased Zn doping concentrations and a concurrent reduction in the band gap values. This adjustment aligns the material's band gap with those commonly found in key components utilized in DSSC and PSC cells, suggesting promising applications in these crucial technological domains.

Barium stannate/graphitic carbon nitride S-scheme heterojunction as an efficient photocatalyst for removal of toxic coloring agents under visible light

Photocatalyst heterojunctions are crucial for efficient long-term carrier separation and for increasing the photocatalytic efficiency of single catalysts. A simple and low-cost method of fabricating barium stannate (BaSnO3, ZSO) is described in this paper, as well as the co-precipitation process with ultrasonic assistance that is used to produce barium stannate/graphitic carbon nitride nanocomposites (BaSnO3/g-C3N4, BSO/CN) with varying amounts of BSO. Various analytical techniques were used to evaluate the purity, morphology, and structure of the products, including XRD, FTIR, EDS, FESEM, TEM, BET, DRS, and PL. CN lowered the bandgap of BSO, allowing it to be used in the visible spectrum according to DRS data. An evaluation of BSO, CN, and several BSO/CN nanocomposites was conducted to determine their ability to degrade erythrosine (ER) and eriochrome black T (EBT). Results showed that the efficiency of the dye was affected by several factors, including the concentration of BSO, the quantity of catalyst, and the dye concentration. In a BSO/CN nanocomposite containing 0.1 g of BSO and 60 mg of ZSO/CN (0.1:1), 88.4 % of ER was degraded. As revealed by the scavenger experiments, superoxide radicals exhibit remarkable properties in photoreactions. It appears that higher levels of competence (88.4 %) were associated with the highest rate constant (k = 0.0256 min−1) according to the kinetics survey.

Engineering the optical, and dielectric properties of (PVA: PVP)/BaSnO3 polymer nanocomposites as promising films for optoelectronics and energy storage applications

AbstractThis work is devoted to optimizing the optical and dielectric parameters of polyvinyl alcohol (PVA): polyvinyl pyrrolidone (PVP) (1:1) polymer nanocomposites by controlling barium stannate contents (BaSnO3) aspiring to engage it into flexible optoelectronics and thermally stable capacitors. Herein, high purity BaSnO3 was synthesized by solid‐state route and loaded with different ratios (5–20 wt%) into PVA/PVP blend to form films by solution casting method. Further, the degree of crystallinity (Xc) was highly increased upon increasing the filler contents (BaSnO3), as confirmed by X‐ray diffractometer measurement. The surface morphology pictured by a field emission scanning electron microscope revealed the variation of the surface from smooth to rough surface upon insertion of BaSnO3. The thermodynamic parameters including enthalpy (ΔH), entropy (ΔS), and Gibb's free energy (ΔG) were extracted from TGA measurements and studied in detail. The optical characteristics of plain PVA/PVP and polymer nanocomposite films are explored by UV–Vis–NIR spectrophotometer. The presence of charge‐transfer complexes within the polymer nanocomposites was certified via shifting of band gap energy from 5.02 to 4.33 eV and variation of band tailing energy (Eu) from 0.22 to 0.44 eV. The real and imaginary part of optical conductivity (σp1, σp2) was confirmed to be enhanced with the insertion of BaSnO3. It is also found that the dielectric constant and DC current increased with the insertion of BaSnO3 content, while the dielectric loss decreases. The findings recommend these polymer nanocomposites as a good candidate for green energy applications and high‐performance capacitors.

Co-doping effect on the microstructural and electrical properties of barium stannate materials

Proton-conducting perovskite oxides are of considerable interest to researchers as promising electrolytes for low- and intermediate solid oxide electrochemical cells. Therefore, designing new potential proton-conducting phases and improving the functional properties of known materials are of great importance from both fundamental and applied viewpoints. In the present work, BaSnO3 was selected as a reference proton-conducting system and then a co-doping strategy was employed to analyze ‘composition – structure – microstructure – transport properties’ relationships. To perform such an analysis, the properties of previously studied BaSn0.7M0.3O3–δ (M = In, Sc, Y) compounds were compared here to their co-doped derivatives, BaSn0.7In0.15Sc0.15O3–δ, BaSn0.7Y0.15Sc0.15O3–δ, and BaSn0.7In0.15Y0.15O3–δ. It is found that the type of dopant affects the materials sinterability, when more coarse-crystalline ceramics are formed with increasing the average ionic radii at the Sn-position. The introduction of Y3+-cations reduces both ionic and hole conductivities compared to single-doped with In3+ or Sc3+ barium stannate materials. However, simultaneous doping with In3+/Sc3+ cations minimizes the contribution of hole conductivity compared to that of Sc-doped barium stannate with the same acceptor dopant concentration.

Tungsten-doped barium stannate as a transparent conducting film

Epitaxial W-doped BaSnO3 (on Sn site) thin films with promising Vis-NIR transparency and comparable carrier mobility have been fabricated on SrTiO3(100) substrate, implying its potential as a candidate for Vis-NIR transparent conducting oxide.

Performance improvement of perovskite/CIGS tandem solar cell using barium stannate charge transport layer and achieving PCE of 39 % numerically

The way to overperform the Shockley-Quisser limit of power conversion efficiency (PCE) for single junction solar cell is tandem device. In this work, a perovskite solar cell (PSC) and Copper Indium Gallium Selenide (CIGS) based solar cell (CSC) are individually optimized and implemented as PSC/CSC tandem (PSSC) device in SCAPS-1D. The perovskites which are highly stable and optically fit for PSSC, consists of triple or quadruple mixed cations, lead (Pb) and halides and the most popular perovskite of this kind is Cs0.15MA0.15 FA0.70Pb(I0.85Br0.15)3 which is used as absorber material in the PSC presented in this work. Another important aspect of PSC is selection of suitable material for charge transport layers. For the first time, a never explored before the oxide perovskite namely the barium stannate (BaSnO3) is used as electron transport layer (ETL) along with NiO as hole transport layer (HTL) in the reported PSC which provides impressive short circuit current density (JSC), open circuit voltage (VOC), fill-factor (FF) and PCE of 23.89 mAcm−2, 1.48 V, 88.92 %, 31.53 % respectively. Moreover, a comprehensive analysis of the PSC without HTL but with BaSnO3 as ETL is carried out and improved records are observed. Finally, the optimized PSSC which consists of HTL free PSC and CSC can deliver a PCE as high as 39 % which is the highest ever predicted value and is attributed to the well-matched energy band alignment of BaSnO3 with the absorber. This work can be a potential contributor to the high efficiency solar cell fabrication roadmap.

Highly transparent and low resistance BaSnO3/Ag nanowire composite thin films

Highly transparent and low resistance composite thin films with a bilayer structure composed of barium stannate (BSO) and silver nanowires (Ag NWs) are manufactured on polycarbonate (PC) substrates. The Ag NW networks are embedded into the BSO thin films prepared by magnetron sputtering. The BSO/Ag NW composites possess low sheet resistance of 9.1 Ω/sq. and high transmittance of 84.7 % at four spin-coating cycles, these are superior to that of bare Ag NWs and flexible ITO films. The mechanisms of improved transmittance and conductivity of BSO/Ag NW composites are proposed. The resistance remains mostly intact after beading tests at curvature radius of 3.0 mm and taping tests with 30 cycles, indicating the excellent flexibility and adhesiveness. More importantly, the BSO/Ag NW composites possess excellent oxidation resistance, thermal and chemical stabilities. These results suggest that BSO/Ag NW composites can be utilized for the fabrication of flexible electronics.

Synthesis of BaSnO3 as a Highly Dispersed Additive for the Preparation of Proton-Conducting Composites

The process of thermolysis of barium hydroxostannate BaSn(OH)6 as a precursor for preparing barium stannate BaSnO3 has been investigated using the method of differential thermal analysis. Thermal decomposition products of the precursor were characterized using X-ray diffraction, IR spectroscopy, low-temperature nitrogen adsorption, and scanning electron microscopy. It was shown that dehydration at nearly 270 °C resulted in the formation of an X-ray amorphous multiphase product, from which single-phase barium stannate crystallized at temperatures above 600 °C. The synthesized barium stannate was used as a functional additive to prepare composite proton electrolytes in the CsHSO4-BaSnO3 system. The structural and transport properties of the obtained system were investigated. It is shown that the highly conductive state of the salt is stabilized in a wide range of temperatures. High conductivity values of composite solid electrolytes in the medium temperature range create the possibility of their use as solid electrolyte membrane materials.

CO gas sensing characteristics of BaSnO3 epitaxial films prepared by PLD: The effect of film thickness

In the present work, perovskite Barium Stannate (BaSnO3) thin films of varying thickness were investigated for carbon monoxide (CO) gas sensing application. Epitaxial BaSnO3 thin films of thickness (90, 270 and 360 nm) were grown on MgO substrates by using pulsed laser deposition technique. The enhanced electrical properties of the films with decreasing thickness can be attributed to the increased amount of Sn4+ ions in the film. An increase in CO gas sensing response of thin films was observed with decreasing film thickness. BaSnO3 thin film having 90 nm thickness exhibits a higher gas sensing response of 58% at 400 °C, which is a quite lower temperature as compared to the previous works in similar systems. This high value is attributed to the presence of large number of grains and grain boundaries providing easy adsorption and desorption of oxygen species at the surface, confirmed by the atomic force microscopy and X-ray photoelectron spectroscopy, respectively.