Phase transitions and slow spin dynamics of slightly inverted A-site spinel CoAlGaO.

We report the properties of an A-site spinel magnet, CoAlGaO, and analyze its anomalous, low-temperature magnetic behavior, which is derived from inherent, magnetically frustrated interactions. Rietveld analysis of the x-ray diffraction profile for CoAlGaOrevealed that the metallic ions were randomly distributed in the tetrahedral (A-) and octahedral (B-) sites in the cubic spinel structure. The inversion parametercould be controlled by varying the gallium (Ga) composition in the range 0.

Research progress on surface modifications for phosphors used in light-emitting diodes (LEDs).

Stable and efficient phosphors are highly important for light-emitting diodes (LEDs) with respect to their application in solid-state lighting, instead of conventional lamps for general lighting. However, some problems, like low stability, low photoluminescence (PL) efficiency, and serious thermal degradation, are commonly encountered in phosphors, limiting their applications in LEDs. Surface modifications for some phosphors commonly used in LED lighting, including fluoride, sulphide, silicate, oxide, nitride, and oxynitride phosphors, are presented in this review.

Preparation of Oriented ZnO Rod Arrays Using Hexagonal Plate-Like Particles as a Seed Layer.

ZnO rod film is a promising material for electrodes and sensors due to its large surface area and high electrical conductivity. One of the drawbacks of conventional ZnO rod film is the random orientation of rods. In this study, an oriented ZnO seed layer composed of hexagonal plate-like ZnO particles was prepared by dip-coating.

A review on functional nanoarchitectonics nanocomposites based on octahedral metal atom clusters (Nb, Mo, Ta, W, Re): inorganic 0D and 2D powders and films.

This review is dedicated to various functional nanoarchitectonic nanocomposites based on molecular octahedral metal atom clusters (Nb, Mo, Ta, W, Re). Powder and film nanocomposites with two-dimensional, one-dimensional and zero-dimensional morphologies are presented, as well as film matrices from organic polymers to inorganic layered oxides. The high potential and synergetic effects of these nanocomposites for biotechnology applications, photovoltaic, solar control, catalytic, photonic and sensor applications are demonstrated.

High performance {NbTaX}@PVP (X = Cl, Br) cluster-based nanocomposites coatings for solar glazing applications.

The development of highly ultraviolet (UV) and near-infrared (NIR) absorbent transparent coatings is an important enabling technology and area of research for environmental sustainability and energy conservation. Different amounts of K[{NbTaX }X ] cluster compounds (X = Cl, Br) dispersed into polyvinylpyrrolidone matrices were prepared by a simple, nontoxic and low-cost wet chemical method. The resulting solutions were used to fabricate visibly transparent, highly UV and NIR absorbent coatings by drop casting.

Humidity Sensitivity of Chemically Synthesized ZnAlO/Al.

Humidity sensitivity is evaluated for chemically synthesized ZnAlO/Al devices. We succeeded in synthesizing the ZnAlO/Al device by applying chemical techniques only. Hydrothermal treatment for the anodized aluminum (AlO/Al) gives us the device of the ZnAlO/Al structure.

Hafnium Oxide Nanostructured Thin Films: Electrophoretic Deposition Process and DUV Photolithography Patterning.

In the frame of the nanoarchitectonic concept, the objective of this study was to develop simple and easy methods to ensure the preparation of polymorphic HfO2 thin film materials (<200 nm) having the best balance of patterning potential, reproducibility and stability to be used in optical, sensing or electronic fields. The nanostructured HfO2 thin films with micropatterns or continuous morphologies were synthesized by two different methods, i.e.

Controlling the Deposition Process of Nanoarchitectonic Nanocomposites Based on {NbTaX} Octahedral Cluster-Based Building Blocks (X = Cl, Br; 0 ≤ x ≤ 6, n = 2, 3, 4) for UV-NIR Blockers Coating Applications.

The antagonism between global energy needs and the obligation to slow global warming is a current challenge. In order to ensure sufficient thermal comfort, the automotive, housing and agricultural building sectors are major energy consumers. Solar control materials and more particularly, selective glazing are part of the solutions proposed to reduce global energy consumption and tackle global warming.

Nanoarchitectonics of Glass Coatings for Near-Infrared Shielding: From Solid-State Cluster-Based Niobium Chlorides to the Shaping of Nanocomposite Films.

The high potential of [{NbCl}L] cluster-based building blocks as near-infrared radiation blockers for energy saving applications is exposed in the present paper (i = inner edge-bridging ligand, a = apical ligand of the Nb; L = HO and/or Cl). To do so, a combined experimental and theoretical investigation of edge-bridged [{NbCl}Cl(HO)] cluster unit series ( = 0, 4, 6; = 2, 3, 4; = 2, 3, 4) has been carried out. By using the K[{NbCl}Cl] starting solid-state precursor, we explored the behavior of the [{NbCl}Cl] cluster unit during the different steps of its integration as a building block into a polyvinylpyrrolidone (PVP) matrix to form a glass coating composite denoted {NbCl}@PVP ( = 2 or 3).

Video Processing Electrophoretic Measurements under High Electric Fields for Sub-millimeter Particles in Oil.

Electrokinetic properties such as the mobility, surface charge, and zeta potential of sub-millimeter particles are vital parameters in various industrial applications. Their measurement and control in aqueous media have been extensively studied. However, despite their growing importance, the electrokinetic properties of organic solvents have not been studied as thoroughly as those of aqueous media.

Evidence of the Ambipolar Behavior of Mo Cluster Iodides in All-Inorganic Solar Cells: A New Example of Nanoarchitectonic Concept.

Ambipolar materials such as carbon nanotubes, graphene, or 2D transition metal chalcogenides are very attractive for a large range of applications, namely, light-emitting transistors, logic circuits, gas sensors, flash memories, and solar cells. In this work, it is shown that the nanoarchitectonics of inorganic Mo cluster-based iodides enable to form thin films exhibiting photophysical properties that enable their classification as new members of the restricted family of ambipolar materials. Thus, the electronic properties of the ternary iodide Cs[{MoI}I] and those of thin films of the aqua-complex-based compound [{MoI}I(HO)]·HO were investigated through an in-depth photoelectrochemical study.

Synthesis of novel hexamolybdenum cluster-functionalized copper hydroxide nanocomposites and its catalytic activity for organic molecule degradation.

A novel heterogeneous catalytic nanomaterial based on a molybdenum cluster-based halide (MC) and a single-layered copper hydroxynitrate (CHN) was first prepared by colloidal processing under ambient conditions. The results of the elemental composition and crystalline pattern indicated that CHN was comprehensively synthesized with the support of the MC compound. The absorbing characteristic in the ultraviolet and near-infrared regions was promoted by both of the ingredients.

Spontaneously formed gradient chemical compositional structures of niobium doped titanium dioxide nanoparticles enhance ultraviolet- and visible-light photocatalytic performance.

Semiconductor photocatalysts showing excellent performance under irradiation of both ultraviolet (UV)- and visible (VIS)-light are highly demanded towards realization of sustainable energy systems. TiO is one of the most common photocatalysts and has been widely investigated as candidate showing UV/VIS responsive performance. In this study, we report synthesis of Nb doped TiO by environmentally benign mechanochemical reaction.

Revisiting properties of edge-bridged bromide tantalum clusters in the solid-state, in solution and vice versa: an intertwined experimental and modelling approach.

Edge-bridged halide tantalum clusters based on the {TaBr} core have been the topic of many physicostructural investigations both in solution and in the solid-state. Despite a large number of studies, the fundamental correlations between compositions, local symmetry, electronic structures of [{TaBr}L] cluster units (L = Br or HO, in solution and in the solid-state), redox states, and vibrational and absorption properties are still not well established. Using K[{TaBr}Br] as a starting precursor (i: inner and a: apical), we have investigated the behavior of the [{TaBr}Br] cluster unit in terms of oxidation properties and chemical modifications both in solution (water and organic solvent) and after recrystallization.

Development of novel bone-like nanocomposite coating of hydroxyapatite/collagen on titanium by modified electrophoretic deposition.

Electrophoretic deposition (EPD) is a simple, rapid, and inexpensive technique to accomplish uniform coatings with controlled thicknesses. The EPD using binders that do not require a thermal degreasing process, which also eliminates the polymer components of the composite, are required for coating polymer-ceramic composites. This study demonstrated the application of a modified EPD technique utilizing Mg ions to coat a bone-like hydroxyapatite/collagen nanocomposite (HAp/Col) on a titanium (Ti) substrate.

Electrophoretically Deposited Layers of Octahedral Molybdenum Cluster Complexes: A Promising Coating for Mitigation of Pathogenic Bacterial Biofilms under Blue Light.

The fight against infective microorganisms is becoming a worldwide priority due to serious concerns about the rising numbers of drug-resistant pathogenic bacteria. In this context, the inactivation of pathogens by singlet oxygen, O(Δ), produced by photosensitizers upon light irradiation has become an attractive strategy to combat drug-resistant microbes. To achieve this goal, we electrophoretically deposited O(Δ)-photosensitizing octahedral molybdenum cluster complexes on indium-tin oxide-coated glass plates.

Robust Structurally Colored Coatings Composed of Colloidal Arrays Prepared by the Cathodic Electrophoretic Deposition Method with Metal Cation Additives.

Structurally colored coatings composed of colloidal arrays of monodisperse spherical particles have attracted great attention owing to their versatile advantages, such as low cost, resistance to fading, and low impacts on the environment and human health. However, the weak mechanical stability is considered to be a major obstacle for their practical applications as colorants. Although several approaches based on the addition of polymer additives to enhance the adhesion of particles have been reported, the challenge remains to develop a strategy for the preparation of structurally colored coatings with extremely high robustness using a simple process.

Rapid Growth of Colloidal Crystal Films from the Concentrated Aqueous Ethanol Suspension.

Developing a rapid fabrication of colloidal crystal film is one of the technical issues to apply to wide and various fields. We have been investigating a drying process of colloidal aqueous ethanol (EtOH) suspension formed by electrophoretic deposition (EPD). Here, the detailed formation mechanism of the colloidal crystal films with the closest packing structure was investigated by optical microscope and spectroscopy.

Zn-Al Layered Double Hydroxide Film Functionalized by a Luminescent Octahedral Molybdenum Cluster: Ultraviolet-Visible Photoconductivity Response.

A novel UV-Vis photodetector consisting of an octahedral molybdenum cluster-functionalized ZnAl layered double hydroxide (LDH) has been successfully synthesized by co-precipitation and delamination methods under ambient conditions. The electrophoretic deposition process has been used as a low-cost, fast, and effective method to fabricate thin and transparent nanocomposite films containing a dense and regular layered structure. The study provided evidence that the presence of the Mo cluster units between the LDH does not affect the ionic conduction mechanism of the LDH, which linearly depends on the relative humidity and temperature.

Solution-mediated nanometric growth of α-FeO with electrocatalytic activity for water oxidation.

This paper describes a simple, low-temperature, and environmentally friendly aqueous route for the layer-by-layer nanometric growth of crystalline α-FeO. The formation mechanism involves alternative sequences of the electrostatic adsorption of Fe ions on the surface and the subsequent onsite oxidation to Fe. A combination analysis of X-ray diffraction, scanning electron microscopy, UV-Vis spectroscopy, and X-ray photoelectron spectroscopy revealed that α-FeO is directly formed without post-growth annealing designed chemical reactions with a growth rate of 1.

Enhanced visible-light photocatalytic activity of anatase-rutile mixed-phase nano-size powder given by high-temperature heat treatment.

Nano-size EVONIK AEROXIDE P25 titanium dioxide, TiO, powder was heat-treated at temperatures, 700-900°C, in air. An X-ray diffraction study showed that the P25 powder is composed of approximately 20 and approximately 80 mass% of rutile and anatase phases, respectively. It was also shown that the transformation from anatase to rutile induced by high-temperature heat treatment was almost completed at 750°C, whereas a small amount (less than 3 mass%) of anatase phase was still left even in the powder heat-treated at 900°C.

ITO@SiO and ITO@{MBr}@SiO (M = Nb, Ta) nanocomposite films for ultraviolet-near infrared shielding.

Transparent optical thin films for energy saving applications have recently gained substantial prominence for functional window processes. In this study, highly visible transparent nanocomposite films with ultraviolet (UV) and near-infrared (NIR) blocking capabilities are reported. Such nanocomposite films, prepared by electrophoretic deposition on ITO-coated glass, are composed of indium tin oxide (ITO) nanocrystals (9 nm) and octahedral metal atom clusters (1 nm, Nb or Ta) embedded into silica nanoparticles (∼80 nm).

Transparent functional nanocomposite films based on octahedral metal clusters: synthesis by electrophoretic deposition process and characterization.

Transparent optical thin films have recently attracted a growing interest for functional window applications. In this study, highly visible transparent nanocomposite films with ultraviolet (UV)-near-infrared (NIR)-blocking capabilities are reported. Such films, composed of Mo and Nb octahedral metal atom clusters (MC) and polymethylmethacrylate polymer (PMMA), were prepared by electrophoretic deposition on indium tin oxide-coated glass (ITO glass).