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A comparison of water photo-oxidation and photo-reduction using photoelectrodes surface-modified by deposition of co-catalysts: Insights from photo-electrochemical impedance spectroscopy
摘要： The purpose of this research paper is to highlight the similarities in the kinetic treatment between water photo-oxidation into molecular oxygen and water photo-reduction into molecular hydrogen, using photoelectrodes surface modified by deposition of co-catalysts. Photo-anodes made of TiO2 nanorods surface-covered by crystals of cobalt Zeolitic Imidazolate Framework (ZIF-67), and photo-cathodes made of Rh:SrTiO3 particles surface-modified by adsorption of molecules of trisdioximate hexa-chlorine cobalt (II) clathrochelate (Co(Cl2Gm)3(BCH3)2), have been prepared and used for water photo-oxidation and photo-reduction experiments, respectively. Both photoelectrodes have been characterized by SEM and cyclic voltammetry under illumination conditions. Charge transfer mechanisms have been investigated by photo-electrochemical impedance spectroscopy (PEIS). It is shown that for both systems, the presence of a co-catalyst increases the charge transfer kinetics, and that the trapping resistance is larger than the charge transfer resistance, at any operating potential.
关键词： Water photo-oxidation,Titanium dioxide nanorods,Strontium titanate,Water photo-reduction,ZIF-67 MOF
更新于2025-09-23 15:23:52
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Thin Films of Barium Strontium Titanate from the Viewpoint of Light-Based Applications
摘要： In this paper we report results from optical transmittance spectroscopy complemented with data on structure from XRD measurements to determine optical properties of a series of as-deposited and annealed (at 900 °C) BaSrTiO3 (BST) thin films deposited by RF magnetron sputtering. The members of the series differ by the substrate temperature and additional oxygen to accompany argon in the deposition chamber. The perovskite structure with weak preferred (110) orientation was detected for annealed BST thin films whilst the as-deposited films were amorphous. Dispersive optical properties – refractive indices, absorption coefficients and optical band gaps were determined from transmittance spectra. After annealing refractive indices increase to prove the densification of material accompanied by the thickness shrinkage. Optical band gaps calculated either by Tauc procedure or determined as iso-absorption levels are also found to be deposition dependent.
关键词： absorption coefficient,thin films,barium strontium titanate,refractive index,optical band gap
更新于2025-09-23 15:23:52
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Study of the fabrication and organization properties of copper-based Ba<inf>1?x</inf>Sr<inf>x</inf>TiO<inf>3</inf> composites
摘要： Barium strontium titanate ceramic particles which have negative thermal expansion properties when it reaches reinforcement and copper which have high thermal conductivity are choosen as matrix of composites. Different content of strontium in barium strontium titanate ceramic particles reinforced copper matrix composites are prepared by Spark Plasma Sintering for electronic packaging applications. The methods of microstructure analysis are employed to observe the morphology of reinforcement and matrix in composites, and interfacial characteristics. Thermal expansion instrument and thermal conductivity equipment are used to test and analyze the thermal expansion and thermal conductive ability of the composites. And the conductivity of the composites is tested by intelligent resistance tester.
关键词： Thermal expansion ability,Barium strontium titanate,Copper matrix composites
更新于2025-09-23 15:22:29
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Systematic microstructural development with thermal diffusivity behaviour from nanometric to micronic grains of strontium titanate
摘要： Strontium titanate is a promising candidate for applications in thermoelectric, thermal management applications, and modern electronic devices because of its desirable thermal stability, chemical stability, and semiconducting behaviour. However, the absence of its important systematic development, having grain size from several nanometric up to micronic size with evolving thermal diffusivity behaviour, triggers the need for filling up the vacuum. Two different heat treatments have been carried out onto the samples which were with presintering and without presintering. Nanometer-sized compacted powder samples were sintered from 500 to 1400 °C using 100 °C increments. The parallel characterizations of structural, microstructural and thermal diffusivity properties were systematically carried out. Interestingly, three significant value-differentiated groups: weak, moderate, and strong thermal diffusivity were observed, resulting from the influence of different phonon-scattering mechanisms through a systematic development of microstructural properties for both heat treatments.
关键词： Strontium titanate,Thermal conductivity,Thermal diffusivity,Microstructure
更新于2025-09-23 15:21:21
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Structural and dielectric properties of PLD grown BST thin films
摘要： Thin films of Barium Strontium Titanate (BaSrTiO3, BST) have been deposited on platinised silicon substrate using pulsed laser deposition (PLD) technique. The effect of growth pressure and temperature during the film deposition on the crystallization and dielectric behaviour of the BST films has been studied. The effect of plume dynamics due to variation in deposition parameters present inside the deposition chamber has also been investigated. The dielectric constant of the BST thin film deposited under variable deposition pressures increases with increase in deposition temperature at a frequency of 1 MHz. The BST thin film deposited at 1.33 × 10?4 bar and 800 °C substrate temperature exhibits high dielectric constant (≈475) with 65% tunability which can be efficiently exploited for the realization of tunable resonators and filters.
关键词： Barium Strontium Titanate,BST,PLD,tunability,dielectric properties
更新于2025-09-23 15:21:21
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Structural and dielectric properties of sol–gel derived Ba<sub>1–<i>x</i></sub>Sr<sub><i>x</i></sub>TiO<sub>3</sub> (0 ≤ <i>x</i> ≤ 0.5) ceramics for energy storage applications
摘要： Barium strontium titanate (Ba1–xSrxTiO3, BSTO: x = 0, 0.3 and 0.5) ceramics were prepared by sintering sol–gel derived BSTO powders at 1350 °C for 2 h. Average grain size of BSTO ceramics decreased from 15 to 2 μm with increasing Sr molar fraction. X-ray structural analysis revealed that BSTO ceramics exhibited tetragonal structure (x = 0 and 0.3) and transformed into cubic structure at high Sr molar fraction (x = 0.5) at room temperature. Dielectric constant of the BSTO ceramics was measured between ?60 and 180 °C and frequency range of 1–100 kHz. Temperature transition from ferroelectric to paraelectric phase (Curie temperature: TC) decreased linearly from 125 to ?30 °C as Sr molar fraction increased. The dielectric constant exhibited frequency-independent behavior in the frequency range investigated. A diffuse dielectric constant peak was evident for BSTO with Sr molar fraction of 0.5 due to the effect of fine-grained size. Polarization–electric field (P–E) at room temperature presented a well-defined hysteresis loop for BSTO (x = 0 and 0.3), indicating their ferroelectric characteristics. At a high Sr molar fraction of 0.5, the P–E loop became a linear relation, indicating a paraelectric phase. Energy storage density of BSTO with x = 0 was about 0.2 J/cm3; however, energy storage efficiency was less than 50%. After doping with Sr molar fraction of 0.5, energy storage density decreased to 0.1 J/cm3 but its energy storage efficiency significantly improved to 90%.
关键词： sol-gel method,dielectric,energy storage capacitors,barium strontium titanate
更新于2025-09-23 15:21:01
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Arbitrary control of the diffusion potential between a plasmonic metal and a semiconductor by an angstrom-thick interface dipole layer
摘要： Localized surface plasmon resonances (LSPRs) are gaining considerable attention due to the unique far-field and near-field optical properties and applications. Additionally, the Fermi energy, which is the chemical potential, of plasmonic nanoparticles is one of the key properties to control hot-electron and -hole transfer at the interface between plasmonic nanoparticles and a semiconductor. In this article, we tried to control the diffusion potential of the plasmonic system by manipulating the interface dipole. We fabricated solid-state photoelectric conversion devices in which gold nanoparticles (Au-NPs) are located between strontium titanate (SrTiO3) as an electron transfer material and nickel oxide (NiO) as a hole transport material. Lanthanum aluminate as an interface dipole layer was deposited on the atomic layer scale at the three-phase interface of Au-NPs, SrTiO3, and NiO, and the effect was investigated by photoelectric measurements. Importantly, the diffusion potential between the plasmonic metal and a semiconductor can be arbitrarily controlled by the averaged thickness and direction of the interface dipole layer. The insertion of an only one unit cell (uc) interface dipole layer, whose thickness was less than 0.5 nm, dramatically controlled the diffusion potential formed between the plasmonic nanoparticles and surrounding media. This is a new methodology to control the plasmonic potential without applying external stimuli, such as an applied potential or photoirradiation, and without changing the base materials. In particular, it is very beneficial for plasmonic devices in that the interface dipole has the ability not only to decrease but also to increase the open-circuit voltage on the order of several hundreds of millivolts.
关键词： interface dipole,Fermi energy,strontium titanate,nickel oxide,hole transfer,hot-electron,lanthanum aluminate,gold nanoparticles,photoelectric conversion,Localized surface plasmon resonances
更新于2025-09-23 15:19:57
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Nanostructure and Optical Property Investigations of SrTiO3 Films Deposited by Magnetron Sputtering
摘要： Strontium titanate thin films were deposited on a silicon substrate by radio-frequency magnetron sputtering. The structural and optical properties of these films were characterized by X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, and spectroscopic ellipsometry, respectively. After annealing at 600–800 °C, the as-deposited films changed from amorphous to polycrystalline. It was found that an amorphous interfacial layer appeared between the SrTiO3 layer and Si substrate in each as-deposited film, which grew thicker after annealing. The optical parameters of the SrTiO3 film samples were acquired from ellipsometry spectra by fitting with a Lorentz oscillator model. Moreover, we found that the band gap energy of the samples diminished after thermal treatment.
关键词： thermal treatment,strontium titanate film,optical properties,magnetron sputtering
更新于2025-09-19 17:15:36
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In situ synthesis and oriented growth of flowerlike SrTiO3 on Ti foil with enhanced photoelectrochemical performance
摘要： The oriented growth of flowerlike strontium titanate (SrTiO3) with highly efficient photoelectrocatalytic oxygen evolution reaction performance afforded a high limiting current density of 3.38 mA/cm2 at 600 mV (vs. the reversible hydrogen electrode), and low overpotential and Tafel slope (84 mV/dec) in 1 M KOH solution. Ti foil as a substrate can significantly enhance electron transfer, and flowerlike SrTiO3 with a highly exposed (110) crystal surface was controlled by NaOH concentration and HF. Therefore, the use of Ti and F- as the substrate and the shape-directing additive, respectively, is a feasible and simple strategy to induce a high-energy surface on a photoelectrocatalyst for photoelectrocatalytic splitting of water.
关键词： Orientation growth,Flowerlike strontium titanate,Photoelectrocatalytic
更新于2025-09-19 17:15:36
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Application of barium strontium titanate (BST) as a light sensor on led lights
摘要： Barium Strontium Titanate (BST) film has been successfully produced as a light sensor. The BST film was made by CSD method by reacting barium acetate, strontium acetate and titanium isopropoxide with mole fractions of 0.5; 0.5 and 1, respectively.The BST absorbance test showed that BST film is sensitive to visible light ranging from 475 to 750 nm. The film test showed maximum absorbance at three peak wavelengths, 475 nm, 593 nm, and 702 nm. The energy gap of the BST film was 1.9 eV which showed that the film produced was a semiconductor. The IV test showed that BST film is a photodiode. This was indicated by the shift of the curve when tested in light and dark conditions. The sensitivity test showed BST film is most sensitive to blue light, signified by the most significant change in resistance. The decrease in resistance of blue LED was 0.401KX/lux, while the resistance decrease of green light was 0.051KX/lux and red was 0.288KX/lux. By using optical and electrical properties, BST thin film could be used as light sensors to detect LED lights.
关键词： semiconductor,I-V,absorbance,chemical solution deposition,Barium strontium titanate
更新于2025-09-19 17:13:59