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Nanostructuring of dense SnO2 ceramics by Spark Plasma Sintering
摘要： The spark plasma sintering (SPS) behaviour of pure SnO2 has been studied. Two different SnO2 powders have been studied: a commercial 50–200 nm one and 4–6 nm nanoparticles obtained by precipitation. It has demonstrated that it is not possible to keep pure SnO2 above 1223 K by SPS. Indeed, at 1248 K, SnO appears whereas at higher temperatures, samples are composed by SnO2 and metal Sn. Three different cycles have been developed that allow achieving high densities (≥94%). The study of the grain size shows that when the density increases the grain size increases to reach 60–70 nm for the high density samples. Therefore, SPS can be successfully used to produce dense nanostructured SnO2 ceramics without any sintering agent. Nanostructuring is very efficient to lower thermal conductivity as values as low as 6.59 and 3.99 W m?1.K?1 at 373 and 1000 K respectively, are measured in SPS nanostructured ceramics. Moreover, the transport properties of the dense ceramics are the best reported for undoped SnO2.
关键词： Spark plasma sintering,Tin oxide,Thermal conductivity,Thermoelectric,Nanostructuring
更新于2025-09-19 17:15:36
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Heterostructures of mesoporous TiO2 and SnO2 nanocatalyst for improved electrochemical oxidation ability of Vitamin B6 in pharmaceutical tablets
摘要： The detection of water soluble vitamins using electrochemical method is widely established in pharmaceutical quality control laboratories, and especially the recent advances in hybrid heterostructure nanomaterials has devoted to enhance the significant analytical parameters like sensitivity, selectivity and fast response time. Herein, we report the synthesis of a hybrid heterostructure comprising SnO2 nanoparticles supported mesoporous TiO2, and the obtained nanocomposite were fabricated over glassy carbon electrode (GCE) for the electrochemical oxidation of vitamin B6 in pharmaceutical tablets. The designed SnO2-TiO2/GC modified electrode exhibits well-defined oxidation peak with lowering over-potential and larger signal response compared to the pristine counterparts, and it is mainly due to the formation of abundant active surface layer offered by SnO2 cocatalyst, and thus significantly enhances the electrochemical surface area. Differential pulse voltammetry (DPV) measurements revealed a sharp increase in the anodic peak current upon addition of increasing concentration of vitamin B6. The analytical performance of the modified electrode displayed a wide linear range (0.1 - 31.4 μM), high selectivity, and excellent sensitivity (759.73 μA mM-1 cm-2) with low detection limit (35 nM). Thus, the resultant mesoporous hybrid nanocatalyst provides an efficient electrochemical platform for determination of various potential analytes.
关键词： electrochemical sensor,Tin oxide (SnO2) cocatalyst,mesoporous,Titanium dioxide (TiO2),Vitamin B6
更新于2025-09-19 17:15:36
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Continuous and Ultrafast Preparation of In(OH) <sub/>3</sub> , InOOH, and In <sub/>2</sub> O <sub/>3</sub> Series in a Microreactor for Gas Sensors
摘要： In(OH)3 and InOOH were synthesized in a high-temperature continuous flow microreactor, which was much faster than the hydrothermal synthesis in the Teflon-lined autoclave. The phase transition interval of In(OH)3 and InOOH is measured and the effect of aging temperatures on equilibrium compositions was also theoretically calculated. A transformation from nanorods to nanocubes was observed when the aging temperatures increased. In(OH)3 and InOOH were also synthesized with Sn dopant, which was proved to be beneficial for the transformation from In(OH)3 to InOOH. The sensors based on cubic and hexagonal In2O3 particles showed a fast response (4~5 s) and recovery (12~15 s) speed to acetone vapor at the optimum operating temperature of 290 oC. The sensor based on hexagonal In2O3 showed a higher response than that based on cubic In2O3. This work provided a rapid, continuous and high-temperature synthesis method of an In(OH)3, InOOH and In2O3 series.
关键词： Indium hydroxide (In(OH)3),Tin dopant,Indium oxide(In2O3),Indium oxyhydroxide (InOOH),Gas sensors
更新于2025-09-19 17:15:36
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Structure-activity relationships of hierarchical three-dimensional electrodes with photosystem II for semi-artificial photosynthesis
摘要： Semi-artificial photosynthesis integrates photosynthetic enzymes with artificial electronics, which is an emerging approach to reroute the natural photoelectrogenetic pathways for sustainable fuel and chemical synthesis. However, the reduced catalytic activity of enzymes in bioelectrodes limits the overall performance and further applications in fuel production. Here, we show new insights into factors that govern the photoelectrogenesis in a model system consisting of photosystem II and three-dimensional indium tin oxide and graphene electrodes. Fluorescence microscopy and in situ surface-sensitive infrared spectroscopy are employed to probe the enzyme distribution and penetration within electrode scaffolds of different structures, which is further correlated with protein film-photoelectrochemistry to establish relationships between the electrode structure and enzyme activity. We find that the hierarchical structure of electrodes mainly affects the protein integration, but not the enzyme activity. Photoactivity is more limited by light intensity and electronic communication at the biointerface. This study provides guidelines for maximizing the performance of semi-artificial photosynthesis and also presents a set of methodologies to probe the photoactive biofilms in three-dimensional electrodes.
关键词： semi-artificial photosynthesis,Photosystem II,inverse opal,graphene electrode,indium tin oxide electrode
更新于2025-09-19 17:15:36
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Determination of dopamine using the indium tin oxide electrode modified with direct electrodeposition of gold–platinum nanoparticles
摘要： Gold–platinum (Au–Pt) nanoparticles (NPs) with a ratio of 3:1 solution of chloride salts in the starting electrolyte were deposited on an indium tin oxide (ITO) surface, using a direct electrochemical method, by 40 successive cyclic voltammetry (CV) scans to obtain AuPtNPs/ITO electrode. The deposited nanoparticles were defined by energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) and electrochemical methods. The nanoparticles size of electrodeposited was ~ 30 nm based on SEM results. The efficacy of number of CV scans in the electrodeposition of nanoparticles on the size of electrodeposited nanoparticles was tested. The elemental composition of AuPtNPs/ITO electrode was determined by EDX. Electrochemical studies proved that the electrocatalytic activity of prepared electrode is excellent towards the oxidation of dopamine (DP). The concentration range of DP from 400 nM to 350 μM was linear and limit of detection DP was 20 nM. It was shown that the AuPtNPs/ITO electrode can be used as a sensor with high reproducibility, sensitivity, and long term stability. The selectivity of electrode for determination of DP was verified with investigating the effect of substances by potential interference on the response of electrode. AuPtNPs/ITO electrode was used for the determination of DP in injection and real samples, with acceptable results.
关键词： Dopamine,Gold–platinum alloy,Nanoparticles,Indium tin oxide electrode
更新于2025-09-19 17:15:36
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Antireflection Coatings with Graded Refractive Index of Indium Tin Oxide for Si-based Solar Cells
摘要： The glancing angle deposition (GLAD) technique for fabricating an antire?ection (AR) structure with graded refractive index was applied to silicon substrate by using indium tin oxide (ITO) combining the sputtering method with the evaporation method. In spite of the very limited refractive index pro?le of ITO compared to that of the silicon substrate, the designed AR coatings at wavelengths from near infrared to near ultraviolet showed a re?ectance of only 5.31% at an incident angle of 30? while the transmittance of the ITO AR layer showed a sharp decrease near a wavelength of 400 nm. From these analyses, ITO multilayered AR coatings fabricated by using the GLAD method should improve the performance of an optical device after post-annealing at a low temperature of 160 ?C. When the ITO AR coatings were applied to actual silicon solar cells, it appears that a non-grid electrode cell with ITO AR coatings is possible compared with insulator AR coatings with metal grid electrodes
关键词： Anti-re?ection coating,Solar cells,Glancing angle deposition,Indium tin oxide
更新于2025-09-19 17:15:36
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35.3: Self-formed nano-scale metal-oxide contact interlayer for amorphous silicon tin oxide TFTs
摘要： The formation of metal oxide interlayer is induced by pre-annealing process in the amorphous Silicon-Tin-Oxide thin film transistors (a-STO TFTs) with Mo source/drain electrodes. Cross-sectional high-resolution transmission electron microscopy image confirmed the formation of ~8nm MoOx interlayer. The introduction of MoOx interlayer between Mo electrodes and a-STO improved the electron injection in a-STO TFT. Mo adjacent to the a-STO semiconductor gets oxygen atoms from the oxygen-rich surface of a-STO film to form MoOx interlayer. The self-formed MoOx interlayer acting as an efficient interface modification layer could conduce to the stepwise internal transport barrier formation while blocking Mo atoms diffuse into a-STO layer, which would contribute to the formation of ohmic contact between Mo and a-STO film.
关键词： self-formed interlayer,amorphous Silicon-Tin-Oxide,work function,Thin film transistors,ohmic contact
更新于2025-09-19 17:15:36
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On the Adherence of Chemically Deposited CdS Films to Common Inorganic Substrates: Effect of Cd <sup>2+</sup> Concentration in Solution, Substrate Surface Chemistry, and Reaction Temperature
摘要： The bad adherence to the substrate of chemical-solution-deposited chalcogenide films in alkaline solution is a current technological problem. However, this issue is belittled since is commonly solved by employing pre-sensitized substrates or by empirically changing the deposition parameters until 'finding' the 'proper' chemical formulation. For these reasons, the issue of the adherence has not been previously studied. The present research aims to properly discuss the issue of adherence by taking as example CdS. As a substrate, we used float glass sheets to take advantage of this interesting flat glass (different tin content). It was found that both the surface chemical composition of the substrate and the concentration of Cd2+ in the reaction solution play important roles in the adherence of the CdS thin films; an important effect of temperature was also found. The results were also consistent for indium tin oxide and silicon wafer surfaces. We propose a general surface reaction scheme which considers both the surface reactive sites and the hidroxo–cadmium–thiourea complexes of the reaction solution, as well as the formation of a surface intermediate entity which dissociates into a CdS molecule bonded to the surface and byproducts. The adherence depends on the quantity of surface intermediate entities formed, and therefore, the conditions that promote their formation contribute to the adherence: high reagent concentration, high-reactive surface sites, and low reaction temperature.
关键词： Float Glass,X-Ray Photoelectron Spectroscopy (XPS),Chemical Bath Deposition,Film Adherence,Tin Oxide
更新于2025-09-19 17:15:36
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Dependence of pH on phase stability, optical and photoelectrical properties of SnS thin films
摘要： This study reports the effect of pH value of the reaction solution (5, 5.8 and 6.5) on growth rate of SnS films deposited by chemical bath deposition and their characteristics such as X-ray diffraction (XRD), surface morphology, phase stability, optical and photoelectrical. XRD analysis reveals that the films exhibit an orthorhombic structure with polycrystalline nature, in addition to the presence of the secondary phase Sn2S3 at pH 6.5. Field emission scanning electron microscopy observations show the formation of nanoflowers. Raman spectra manifest the presence of Sn2S3 phase, where its peak intensity gradually reduces until disappearance with decreasing pH value from 6.5 to 5. Furthermore, the enhancement in the dark current (conductivity) value of the thin films occurs with decreasing pH value, as well as increasing in the value of photocurrent under illumination of near-infrared 750 nm. Conversely, the sensitivity value decreased with decreasing pH. Moreover, the energy gap value ranges from 1.34 to 1.51 eV with increasing pH. The as-obtained results demonstrate the key role of pH in controlling SnS films characteristics to achieve high quality films for the applications of photodetectors and solar cells.
关键词： Phase,Raman,Tin sulfide,Sensitivity,Photodetector
更新于2025-09-19 17:15:36
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Oxygen controlled E-beam evaporation deposited p-SnOx thin film for photosensitive devices
摘要： Thin SnOx films of different thicknesses at different oxygen pressures were deposited on glass substrate using reactive E-beam evaporation technique. Significant changes in the optical and structural properties of the films with change in oxygen pressure are observed. Experimentally obtained absorption coefficient and band gap of SnOx suggests its prospective use as suitable absorber material for photoconductive and photovoltaic devices. In addition to the oxygen pressure, thickness of SnOx layer has also an important role on its optical and structural properties.
关键词： Semiconductor,Tin oxide,Optical property,Crystal structure,Thin film
更新于2025-09-19 17:13:59