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Dual functionality of K0.3WO3/Ag2O nanocomposites for smart window: Energy saving and visible photocatalytic self-cleaning performance
摘要： Series of novel K0.3WO3/Ag2O nanocomposites were successfully prepared by simple two steps method. An exciting fact that near-infrared light shielding and visible photocatalytic self-cleaning effects are integrated into the K0.3WO3/Ag2O film (weight ratio of K0.3WO3 to Ag2O = 30) could offer significant potential applications in smart windows. Furthermore, the optical properties and photocatalytic activity of the composites could be tuned by adjusting the weight ratio of K0.3WO3 to Ag2O. The obtained K0.3WO3/Ag2O films presented enhanced photocatalytic self-cleaning performance compared with pure K0.3WO3 under visible light irradiation. The improved self-cleaning performance of the K0.3WO3/Ag2O composites was ascribed to a combined contribution of the matched energy band structures and boosted separation efficiency of photo-generated carriers. An approximately 2.3°C-3.4 °C decrease in inner temperature was obtained for the heat box covered with K0.3WO3/Ag2O coated glass. Therefore, the proposed K0.3WO3/Ag2O (weight ratio of K0.3WO3 to Ag2O = 30) smart coating is a promising material for self-cleaning energy-saving windows.
关键词： Self-cleaning,Visible photocatalytic,Ag2O,KxWO3,Tungsten bronze,NIR shielding
更新于2025-11-19 16:56:35
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Time-and-Space Resolved Cathode Plasma Expansion Velocities in Magnetically Insulated Coaxial Diode With a Metal-Dielectric Cathode
摘要： Time-and-space resolved cathode plasma expansion velocities in magnetically insulated coaxial diodes (MICD) with edged cathodes made of bronze dielectric, bronze, and graphite have been compared through optical diagnosis. The voltage and current of the diode pulse of 260 ns are about 400 kV and 2.8 kA, respectively. The axial and radial expansion velocities of the cathode plasma were obtained through the angled lateral view by utilizing high-speed framing camera combined with the digital image processing methods. In addition, the evolution of the cathode and collector plasmas was visible firstly on the front view at the same time. The bronze-dielectric cathode not only showed low expansion velocity of about 0.5 cm/μs but also had other superior characteristics indicated by the strong emission capability, the fast plasma formation and the uniform plasma distribution. Thereby, the metal–dielectric cathode is a good candidate for applications in a long-pulsed MICD.
关键词： Bronze-dielectric cathode,plasma expansion velocities,high-speed framing camera (HSFC),magnetically insulated coaxial diode (MICD)
更新于2025-09-23 15:23:52
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The <i>h</i> -Sb <sub/>x</sub> WO <sub/> 3+2 <i>x</i> </sub> Oxygen Excess Antimony Tungsten Bronze
摘要： The previously unreported oxygen excess hexagonal antimony tungsten bronze is reported, with a composition of Sb0.5W3O10, in the following denoted as h-SbxWO3 + 2x with x = 0.167, to demonstrate its analogy to classical AxWO3 tungsten bronzes. This compound forms in a relatively narrow temperature range between 580 8C < T < 620 8C. It was obtained as a dark-blue polycrystalline powder, and as thin, needle-shaped, blue single crystals. h-SbxWO3 + 2x crystallizes in the hexagonal space group P6/mmm with the cell parameters a = 7.4369(4) (cid:2) and c = 3.7800(2) (cid:2). The antimony and excess oxygen occupy the hexagonal channels within the network of corner-sharing WO6 octahedra. h-SbxWO3 + 2x has a resistivity of 1300 K (cid:2) 1.28 mW cm at room temperature, with little if any temperature-dependence on cooling. DFT calculations on a simplified model for this compound find a metallic-like electronic structure with the Fermi level falling within rather flat bands, especially around the G point.
关键词： hexagonal bipyramids,metallic oxide,tungsten,antimony,bronze
更新于2025-09-23 15:23:52
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Ultrathin Tellurium Oxide/Ammonium Tungsten Bronze Nanoribbon for Multi-Modality Imaging and Second Near-Infrared Region Photothermal Therapy
摘要： Developing nano-photothermal agents (PTAs) with satisfied photothermal conversion efficiency (PTCE) in the second NIR window (1000-1350 nm, NIR II) holds great promise for enhanced photothermal therapy (PTT) effect. Herein, we develop a NIR-II PTA with advanced PTCE, based on a new two-dimensional (2D) ultrathin tellurium oxide/ammonium tungsten bronze (TeO2/(NH4)xWO3) nanoribbons (TONW NRs). The doped ammonia ions mediated-free electrons injection into the LUMO band of WO3 combined with the electronic transitions between W6+ ions and the lone pair of electrons in Te atoms achieve excellent NIR absorption of TONW NRs resulted from localized surface plasmon resonance (LSPR). The polyethylene glycol functionalized TONW NRs (PEG-TONW NRs) exhibit good stability and biocompatibility, displaying a PTCE high to 43.6%, surpassing many previous nano-PTAs active in the NIR II region, leading to remarkable tumor ablation ability both in vitro and in vivo. Meanwhile, advanced X-ray computed tomography (CT) and photoacoustic (PA) imaging capability of PEG-TONW NRs were also realized. Given the admirable photothermal effect in NIR II region, good biocompatibility and advanced CT/PA imaging diagnosis capability, the novel PEG-TONW NRs is promising in future personalized medicine application.
关键词： photothermal therapy,multimodal imaging,tellurium oxide,two-dimensional nanomaterials,ammonium tungsten bronze,the second NIR window
更新于2025-09-23 15:22:29
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Perovskite Materials - Synthesis, Characterisation, Properties, and Applications || Microwave Dielectrics with Perovskite-Type Structure
摘要： Most electroceramics are ferroelectrics, but microwave dielectrics are mostly paraelectrics with a center of symmetry i. Microwave dielectrics should possess a perfect crystal structure with neither defects nor internal strain in order to be microwave friendly. They have been used in resonators and filters in mobile telecommunications devices. Perovskite and related compounds are also mostly ferroelectrics, but paraelectrics with a perovskite structure also exist, and are used in microwave dielectrics. Owing to the flexibility of the perovskite structure, many kinds of microwave dielectrics with a perovskite structure have been designed for microwave dielectrics. In this chapter, simple and complex perovskite, and perovskite related materials such as pseudo-tungsten-bronze solid solutions and homologous compounds are introduced for microwave dielectrics. The microwave dielectric properties are revealed through the crystalline structure of the material. Therefore, the relationship between the crystalline structure and properties of the material is presented, and is expected to be of use in the design of novel dielectrics. As many superior materials for microwave dielectrics have been developed and are expected to be used in new applications such as wireless sensors and wireless power transfer by resonant coupling, wave absorption by interference and transparent ceramics with no birefringence, these new applications are also discussed.
关键词： Tungsten-bronze compounds,Ordering,Homologous series,Microwave dielectrics,Complex Perovskite
更新于2025-09-23 15:21:01
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Investigations of nano-crystalline Sr0.5Ba0.5Nb2O6 and bulk ceramics synthesized by a polymerization method using PEG400
摘要： Nano-crystalline Sr0.5Ba0.5Nb2O6 was synthesized by a one-pot method using PEG400 and citric acid. Calcination of the (Sr,Ba,Nb)-gel at 600 °C leads to Sr0.5Ba0.5Nb2O6 with a crystallite size of 24(2) nm and a specific surface area of 38.5(10) m2 g?1. Sintering up to 1325 °C leads to ceramics with globular or irregular-shaped grains and average grain sizes between 1.3 and 2.4 μm, whereas higher temperatures lead to a rod-like microstructure. The indirect allowed optical band gap varies between 3.70(5) and 3.29(5) eV. Dielectric measurements show a diffuse phase transition and weak relaxor properties. The maximum of the permittivity occurs between 116 and 147 °C. The frequency dependence of the impedance can be well described by one or two RC-circuits depending on sintering temperature. The melting temperature is determined as 1506(7) °C with ΔHf = 140(20) kJ mol?1. The average linear thermal expansion coefficient is found to be 10.5(5)?10?6 K?1.
关键词： Nano-particle,Strontium barium niobate,Band-gap,Dielectric permittivity,Tungsten bronze
更新于2025-09-23 15:21:01
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Synthesis of Na <i> <sub/>x</sub></i> MoO <sub/>3</sub> crystals through high pressure solid-state reaction
摘要： We report growth of high-purity single crystals of the sodium molybdenum bronzes NaxMoO3 through high pressure solid-state reaction routes. Our results demonstrate that the crystallite sizes of NaxMoO3 can rapidly grow to ～25 μm under a moderate pressure of 4.0 GPa in just 10 min. This discovery provides a starting point for the growth of large single crystals of alkali metal molybdenum bronzes under high pressure.
关键词： High pressure,molybdenum bronze,reaction
更新于2025-09-23 15:21:01
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Properties, fabrication and applications of plasmonic semiconductor nanocrystals
摘要： In semiconductor nanocrystals (NCs), a new regime has been opened in the plasmonic field since the discovery of localized surface plasmon resonances (LSPRs). LSPRs that lead to near-field enhancement, scattering, and resonant absorption around the NC can be tuned in the range from the visible to the near-infrared (NIR) region across a wide optical spectrum by synthetically varying the doping level, and post synthetically via electrochemical control, photochemical control, and chemical oxidation and reduction. In this review, we will focus on the three widely explored and interrelated examples and their manipulation methods of LSPR of (1) hydrogen molybdenum bronze (HxMoO3?y) NCs, (2) hydrogen tungsten bronze (HxWO3?y) NCs, and (3) oxygen vacancy doped molybdenum tungsten oxide (MoxW1?xO3?y) NCs. Finally, a brief outlook on the applications of these plasmonic NCs is presented.
关键词： hydrogen molybdenum bronze,localized surface plasmon resonances,hydrogen tungsten bronze,plasmonic semiconductor nanocrystals,molybdenum tungsten oxide
更新于2025-09-23 15:19:57
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Tetragonal tungsten bronze phase thin films in the Ka??Naa??Nba??O system: Pulsed laser deposition, structural and dielectric characterizations
摘要： Pulsed laser deposition parameters have been determined to synthesize pure Tetragonal Tungsten Bronze (TTB) phase thin films in the (K,Na)-Nb-O system (KNN). In relation to the high volatility of alkaline elements, it was found that the target composition and the target-substrate distance are of first importance. The TTB phase was identified by X-ray and electron diffraction and the surface microstructure consisting mainly of nanorods supports the formation of hallmark of the TTB phase. Poly-oriented nanorods have been obtained on both C-plane sapphire and (111)Pt/TiO2/SiO2/(001)Si substrates whereas horizontal nanorods oriented along the (hk0) planes have been grown on (100) and (110) SrTiO3. All the nanorods are parallel together when grown on (110) SrTiO3 and they present two in-plane orientations rotated of 90° from each other on (100) SrTiO3. Dielectric characteristics (dielectric permittivity e r, and loss tangent tand ) have been measured at low (1 kHz - 1 MHz) and high (1 GHz - 40 GHz) frequencies, on films deposited on Pt coated silicon and sapphire, respectively. A value of e r = 200 at 1 kHz with tand = 0.015 were measured in a parallel plate capacitor configuration, whereas e r = 130 and tand = 0.20 at 10 GHz were retrieved from transmission lines printed on the KNN TTB thin film grown on C-plane sapphire. Raman investigations of the TTB films were performed in the temperature range 77 - 873 K, confirming the TTB phase formation and the absence of structural transition. Piezoelectric Force Microscopy measurements evidenced a piezoelectric signal although no switching could be performed. However the dielectric measurements, complicated by high leakage currents when a DC voltage was applied, did not evidence any proof of ferroelectricity for the undoped KNN TTB films whereas results reported on other niobates (A,A')0.6Nb10O30 (with A: K, Na and A': Sr, Ba, Ca) have shown Curie temperatures, lying between 156°C and 560°C, separating the paraelectric phase (space group: P4/mbm N°127) and the ferroelectric one (space group: P4bm N°100).
关键词： Tetragonal Tungsten Bronze,Nanorods,Dielectric characterizations,K-Na-Nb-O system,Pulsed laser deposition
更新于2025-09-23 15:19:57
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Flexible Alla??Solutiona??Processed Organic Solar Cells with Higha??Performance Nonfullerene Active Layers
摘要： All-solution-processed organic solar cells (from the bottom substrate to the top electrode) are highly desirable for low-cost and ubiquitous applications. However, it is still challenging to fabricate efficient all-solution-processed organic solar cells with a high-performance nonfullerene (NF) active layer. Issues of charge extraction and wetting are persistent at the interface between the nonfullerene active layer and the printable top electrode (PEDOT:PSS). In this work, efficient all-solution-processed NF organic solar cells (from the bottom substrate to the top electrode) are reported via the adoption of a layer of hydrogen molybdenum bronze (HXMoO3) between the active layer and the PEDOT:PSS. The dual functions of HXMoO3 include: 1) its deep Fermi level of ?5.44 eV can effectively extract holes from the active layer; and 2) the wetting issues of the PEDOT:PSS on the hydrophobic surface of the NF active layer can be solved. Importantly, fine control of the HXMoO3 composition during the synthesis is critical in obtaining processing orthogonality between HXMoO3 and the PEDOT:PSS. Flexible all-solution-processed NF organic solar cells with power conversion efficiencies of 11.9% and 10.3% are obtained for solar cells with an area of 0.04 and 1 cm2, respectively.
关键词： nonfullerene organic solar cells,all-solution-processed,hydrogen molybdenum bronze,charge extraction,wetting
更新于2025-09-23 15:19:57