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Electrical Properties of Fluoro-Substituted Perovskites Ba2 ? 0.5xCaNbO5.5 ?xFx
摘要： The effect of F--doping on the transport properties of perovskite-type complex oxides based on barium—calcium niobate Ba2CaNbO5.5 is analyzed. It is found that, regardless of the mechanism of introducing fluoride ions into the oxygen sublattice, the О2– and Н+ conductivities increase in the range of low fluoride concentrations due to an increase in the mobility of current carriers.
关键词： perovskite,anion doping,heterovalent doping,protonic conductivity,ionic conductivity
更新于2025-11-21 11:20:42
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Synthesis of hybrid zinc-based materials from ionic liquids: a novel route to prepare active Zn catalysts for the photoactivation of water and methane
摘要： A new and simple route for the preparation of zinc-based materials is proposed in this work. The synthesis of zinc oxide from the hydrolysis of imidazolium trichlorozincate ionic liquids (ILs) produces catalytic active nanostructured materials, where the size and shape (irregular particles, nanorods) are dependent on the synthetic conditions employed. Indeed, the hydrolysis of trichlorozincate ILs prepared by an equimolar ionic liquid:ZnCl2 ratio afforded irregular particles, while increasing the IL amount (2:1 and 4:1) drives to the formation of nanorods. These hybrid zinc oxide materials were able to promote the photoactivation of water and methane at 25 °C affording up to 1417 μmolH2.g-1.h-1 and up to 67 μmolCO2.g-1.h-1, respectively. Moreover, tuning the reaction conditions a microstructured zinc-based mineral named simonkolleite was prepared with the expected hexagonal-like morphology. This compound was also applied as an alternative and efficient photocatalyst in the activation of water (972 μmolH2.g-1.h-1) and methane (12.6 μmolCO2.g-1.h-1).
关键词： Zinc oxide,photocatalysis,semiconductors,simonkolleite,ionic liquids,nanomaterials
更新于2025-11-21 11:18:25
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Diffusion Behavior of Differently Charged Molecules in Self-Assembled Organic Nanotubes Studied Using Imaging Fluorescence Correlation Spectroscopy
摘要： The diffusion behavior of fluorescent molecules within bolaamphiphile-based organic nanotubes (ONTs) was systematically investigated using imaging fluorescence correlation spectroscopy (imaging FCS). Anionic sulforhodamine B (SRB), zwitterionic/cationic rhodamine B (RB) or cationic rhodamine 123 (R123) was loaded into ONTs having cylindrical hollow structures (ca. 10 nm in inner diameter) with amine and glucose groups on the inner and outer surfaces, respectively. Wide-field fluorescence video microscopy was used to acquire imaging FCS data for dye-doped ONTs in aqueous solutions of different ionic strengths (1 – 500 mM) at different pH (3.4 – 8.4). The diffusion behavior of these dyes was discussed on the basis of their apparent diffusion coefficients (D) that were determined by autocorrelating the time transient of fluorescence intensity at each pixel on an ONT. Molecular diffusion in the ONTs was significantly slowed by molecule-nanotube interactions, as shown by the very small D (10-1 – 10-2 μm2/s). The pH-dependence of D revealed that dye diffusion was basically controlled by electrostatic interactions associated with the protonation of the amine groups on the ONT inner surface. The pH-dependent change in D was observed over a wide pH range, possibly due to electrostatically induced variations in the pKa of the densely packed ammonium ions on the ONT inner surface. On the other hand, the influence of ionic strength on D was relatively unclear, suggesting the involvement of non-coulombic interactions with the ONTs in molecular diffusion. Importantly, individual ONTs of different lengths (1 – 5 μm) afforded similar diffusion coefficients for each type of dye at each solution condition, implying that the properties of ONTs were uniform in terms of solute loading and release. These results highlight the characteristics of molecular diffusion behavior within the ONTs, and will help in the design of organic nanotubes better suited for use as drug vehicles and contaminant adsorbents.
关键词： Electrostatic Interactions,Diffusion Behavior,Ionic Strength,pH-dependence,Imaging Fluorescence Correlation Spectroscopy,Organic Nanotubes
更新于2025-11-19 16:56:42
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A high-performance room temperature methanol gas sensor based on alpha-iron oxide/polyaniline/PbS quantum dots nanofilm
摘要： A high-performance room temperature methanol gas sensor based on alpha-iron oxide/polyaniline/lead sulfide quantum dots (α-Fe2O3/PANI/PbS QDs) nanofilm was demonstrated in this paper, among which the α-Fe2O3 was an urchin-shaped hollow microsphere. The sensing film was fabricated on an epoxy substrate with interdigital electrodes via successive ionic layer adsorption and reaction technique. The prepared α-Fe2O3/PANI/PbS QDs nanocomposite was examined by X-ray diffraction, transmission electron microscopy, X-ray photoelectron spectroscopy, scanning election microscopy and Fourier transform infrared spectrum. The methanol sensing performances of the α-Fe2O3/PANI/PbS QDs film sensor were investigated against methanol from 10 to 100 ppm at room temperature. The experimental results indicated that the methanol sensor in this work had an excellent response, outstanding selectivity and good repeatability at room temperature. The underlying sensing mechanism of the α-Fe2O3/PANI/PbS QDs film toward methanol was ascribed to a series of interactions and changes on the surface of thin films, which make their resistance change greatly. Larger surface area and much more active adsorption sites also played an important role.
关键词： Methanol gas sensor,Room temperature,Successive ionic layer adsorption and reaction,Hydrothermal method,α-Fe2O3/PANI/PbS QDs
更新于2025-11-14 17:15:25
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One-pot synthesis of 3D Cu <sub/>2</sub> S–MoS <sub/>2</sub> nanocomposites by an ionic liquid-assisted strategy with high photocatalytic activity
摘要： Novel 3D Cu2S–MoS2(x : y) nanocomposites with different proportions of Cu2S (x) and MoS2 (y) are synthesized successfully by a one-step hydrothermal method with the assistance of the ionic liquid [BMIM]SCN. The characterization results show that the nanocomposites are self-assembled from nanosheets of Cu2S and MoS2, they display nanoflower morphology and a typical mesoporous structure. The fabrication mechanism of the nanocomposites is investigated using time-dependent experiments, which indicate the key role of the ionic liquid (IL) in the synthesis process. Furthermore, TAA is used as a sulfur source instead of the IL to form a Cu2S–MoS2 nanocomposite, with the aim of further investigating the effects of the IL on the morphology of the composite. Photodegradation of MB under visible light irradiation experiments were used as probe reactions to evaluate the photocatalytic performance of the as-prepared samples. All the nanocomposites show better catalytic activity than Cu2S and MoS2 monomers. Among the different Cu2S–MoS2(x : y) nanocomposites, the Cu2S–MoS2(1 : 1) composite exhibits the most excellent photocatalytic performance and cycling stability.
关键词： Cu2S–MoS2 nanocomposites,hydrothermal synthesis,photocatalytic activity,ionic liquid,methylene blue degradation
更新于2025-11-14 17:04:02
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Percolation Effects in Electrolytically-Gated WS <sub/>2</sub> /Graphene Nano:Nano Composites
摘要： Mixed networks of conducting and non-conducting nanoparticles show promise in a range of applications where fast charge transport is important. While the dependence of network conductivity on the conductive mass fraction (Mf) is well understood, little is known about the Mf-dependence of mobility and carrier density. This is particularly important as the addition of graphene might lead to increases in the mobility of semiconducting nanosheet-network transistors. Here, we use electrolytic gating to investigate the transport properties of spray-coated composite networks of graphene and WS2 nanosheets. As the graphene Mf is increased, we find both conductivity and carrier density to increase in line with percolation theory with percolation thresholds (~8 vol%) and exponents (~2.5) consistent with previous reporting. Perhaps surprisingly, we find the mobility increases modestly from ~0.1 cm2/Vs (for a WS2 network) to ~0.3 cm2/Vs (for a graphene network) which we attribute to the similarity between WS2-WS2 and graphene-graphene junction resistances. In addition, we find both the transistor on- and off-currents to scale with Mf according to percolation theory, changing sharply at the percolation threshold. Through fitting, we show that only the current in the WS2 network changes significantly upon gating. As a result, the on-off ratio falls sharply at the percolation threshold from ~104 to ~2 at higher Mf. Reflecting on these results, we conclude that the addition of graphene to a semiconducting network is not a viable strategy to improve transistor performance as it reduces the on:off ratio far more than it improves the mobility.
关键词： graphene,ionic liquid,thin film transistor,WS2,carrier density,composite,mobility,Printed electronics
更新于2025-10-22 19:40:53
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Hydrophilic Poly(vinylidene Fluoride) Film with Enhanced Inner Channels for Both Water- and Ionic Liquid-Driven Ion-Exchange Polymer Metal Composite Actuators
摘要： This study presents a novel and facile strategy to fabricate a hydrophilic poly(vinylidene fluoride) (PVDF) electrolyte film with enhanced inner channels for a high-performance and cost-effective ion-exchange polymer metal composite (IPMC) actuator. The resultant PVDF composite film is composed of hierarchical micro/nanoscale structures: well-defined polymer grains with a diameter of ～20 μm and much finer particles with a diameter of ～390 nm, producing three-dimensional interconnected, hierarchical inner channels to facilitate ion migration of the electrolyte matrix film has a high porosity of 15.8% and yields a high water uptake of 44.2% and an ionic liquid (IL, [EMIm]·[BF4]) uptake of 38.1% to make both water-driven and IL-driven IPMC actuators because of the introduction of polar polyvinyl pyrrolidone. Compared to the conventional PVDF/IL-based IPMC, both water-driven and IL-driven PVDF-based IPMCs exhibit high ion migration rates, thus effectively improving the actuation frequency and producing remarkably higher levels of actuation force and displacement. Specifically, the force outputs are increased by 13.4 and 3.0 folds, and the displacement outputs are increased by 2.2 and 1.9 folds. Using an identical electrolyte matrix, water-driven IPMC exhibits stronger electromechanical performance, benefiting to make IPMC actuator with high levels of force and power outputs, whereas IL-driven IPMC exhibits a more stable electromechanical performance, benefiting to make long lifetime IPMC actuator in air. Thus, the resultant IPMCs are promising in the design of artificial muscles with tunable electromechanical performance for flexible actuators or displacement/vibration sensors at low cost.
关键词： ionic exchange polymer metal composite (IPMC),ionic liquid (IL),poly(vinylidene fluoride) (PVDF),inner channel,electromechanical response,polyvinyl pyrrolidone (PVP)
更新于2025-09-23 15:23:52
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Novel solid polymer electrolyte based on PMMA:CH3COOLi effect of salt concentration on optical and conductivity studies
摘要： Novel solid polymer electrolyte (SPE) films based on poly(methyl methacrylate) (PMMA) and lithium acetate (CH3COOLi) with different weight ratios of PMMA:CH3COOLi wt% (60:40, 70:30, 80:20 wt%) were prepared by solution casting technique. XRD analysis confirmed the amorphous nature of Li–PMMA SPE films. FTIR analysis revealed the structural changes in polymer by complexation with Li salt. From the optical absorbance studies, the value of lowest energy band gap was found to be 3.06 eV for the composition, PMMA:CH3COOLi (60:40 wt%). From AC impedance studies, the highest value of ionic conductivity 8.21 × 10?5 S/cm at 303 K for the SPE film PMMA:CH3COOLi (60:40 wt%) is observed compared to the reported literature. From the results of Li–PMMA SPE film with high ionic conductivity, it is a promising material for the application of solid-state battery.
关键词： Band gap,Ionic conductivity,Dielectric measurements,Li–PMMA SPE
更新于2025-09-23 15:23:52
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Electrodeposition of lead selenide films from ionic liquids based on choline chloride
摘要： The paper presents some experimental results regarding the electrodeposition of PbSe thin films at 70 oC from two choline chloride (ChCl) based ionic liquids containing PbCl2 and SeO2 as precursors in choline chloride-ethylene glycol (ILEG) and choline chloride-urea (IL) eutectic mixtures. In this article we will detail our investigation of cathodic processes involved during the electrodeposition of binary semiconductor compound, PbSe as well as of singular Pb and Se elements. The cathodic branches of the recorded cyclic voltammograms in the cases of ionic liquids containing both Pb2+ + Se4+ show successively the Se underpotential deposition, Se bulk deposition and Pb deposition followed by a formation of PbSe semiconductor compound. However, at the most negative potentials the Se content of final layers decreases by a partial electrochemical dissolution of Se which reduces to Se2- soluble species. PbSe thin films have been electrodeposited on copper or nickel substrates under potentiostatic control at 70 oC for 0.5-4 h. The adherent and uniform deposits were characterized by SEM-EDX and XRD techniques. SEM images have shown adherent and grey deposits with uniform morphology and cubic PbSe crystals. A stoichiometry of around Pb1.1Se was indicated by EDX elemental analysis. XRD confirmed the formation of PbSe compound, showing a nanocrystalline structure, with crystallites average sizes in the range of 10-35 nm.
关键词： DES ionic liquids,electrodeposition,selenide semiconductors,Lead selenide,cyclic voltammetry
更新于2025-09-23 15:23:52
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[IEEE 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Budapest (2018.7.1-2018.7.5)] 2018 IEEE 2nd International Conference on Dielectrics (ICD) - Bistable Optical Functions of Polyethylene Glycol
摘要： Polyethylene glycol takes both transparent and translucent phases during the phase transition process at around room temperature. This bistability seems useful to create optical devices including 3D displays and tunable random lasers. These devices, however, require a spot-heating technique that controls the phase of each microelement. Self-heating of microelements is achievable if the electric conductivity of the polyethylene glycol is enhanced by the dissolution of alkaline halide salts.
关键词： ionic conduction,bistability,optical functions,polyethylene glycol,phase transition
更新于2025-09-23 15:23:52