Investigation of the Photochromism of WO, TiO, and Composite WO-TiO Nanoparticles.

We report the synthesis of WO, TiO, and TiO-WO nanoparticles by a polyol route, with the objective of studying the influence of the preparation method on their photochromic properties. By combining transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and diffuse reflectance experiments, we show that low W concentrations and high ripening temperatures allow the preparation of WO nanoparticles with high photochromic efficiency. WO-TiO nanocomposites (NCs) prepared by the introduction of a TiO solution in a WO nanoparticle suspension exhibit a strong coloring photochromism, which is attributed to the TiO coating of the WO nanoparticles as it involves the formation of W-O-Ti oxo-bonds in place of W-ν defects.

Controlling differentiation of stem cells bioactive disordered cues.

Ideal bone tissue engineering is to induce bone regeneration through the synergistic integration of biomaterial scaffolds, bone progenitor cells, and bone-forming factors. Biomimetic scaffolds imitate the native extracellular matrix (ECM) and are often utilized as analogues of the natural ECM to facilitate investigations of cell-ECM interactions and processes. , the cellular microenvironment has a crucial impact on regulating cell behavior and functions.

Sequential chiral induction between organic and inorganic supramolecular helical assemblies for the formation of chiral carbon dots.

Self-organised helical bilayers of dicationic gemini surfactants confined in helical silica nanospace were transformed to carbon dots (CDots) pyrolysis. These water-dispersible CDots exhibit electronic absorption spanning the UV and visible range and possess symmetrical circular dichroism (CD) signals, the sign of which depends on the handedness of the helices.

Topotactic fluorination of intermetallics as an efficient route towards quantum materials.

Intermetallics represent an important family of compounds, in which insertion of light elements (H, B, C, N) has been widely explored for decades to synthesize novel phases and promote functional materials such as permanent magnets or magnetocalorics. Fluorine insertion, however, has remained elusive so far since the strong reactivity of this atypical element, the most electronegative one, tends to produce the chemical decomposition of these systems. Here, we introduce a topochemical method to intercalate fluorine atoms into intermetallics, using perfluorocarbon reactant with covalent C-F bonds.

Chemical surface modification of lithium disilicate needles of a silica-based ceramic after HF-etching and ultrasonic bath cleaning: Impact on the chemical bonding with silane.

Objective: Recommendations to obtain the best bonding to silica-based ceramics are to prepare its surface by hydrofluoric-acid HF etching and regular application of a silane. This study investigated how the HF-etching following by ultrasonic water bath cleaning (recommended protocol to improve the bonding with a composite resin), modifies the surface chemistry of a lithium disilicate glass-ceramic and impacts the chemical bonding with silane.

Methods: Lithium disilicate glass-ceramic discs (IPS Emax Press, Ivoclar Vivadent) were mirror polished, etched with 9% HF for 20 s and rinsed 1 min under water.

Design of Metal@Titanium Oxide Nano-heterodimers by Laser-Driven Photodeposition: Growth Mechanism and Modeling.

In order to circumvent the usual nucleation of randomly distributed tiny metallic dots photodeposited on TiO nanoparticles (NPs) induced by conventional UV lamps, we propose to synthesize well-controlled nanoheterodimers (NHDs) using lasers focused inside microfluidic reactors to strongly photoactivate redox reactions of active ions flowing along with nanoparticles in water solution. Since the flux of photons issued from a focused laser may be orders of magnitude higher than that reachable with classical lamps, the production of electron-hole pairs is tremendously increased, ensuring a large availability of carriers for the deposition and favoring the growth of a single metallic dot as compared to secondary nucleation events. We show that the growth of single silver or gold nanodots can be controlled by varying the beam intensity, the concentration of the metallic salt, and the flow velocity inside the microreactor.

Photochromic Behavior of ZnO/MoO Interfaces.

ZnO/MoO powder mixture exhibits a huge photochromic effect in comparison with the corresponding single oxides. The coloring efficiency of such combined material after UV-light irradiation was studied in terms of intensity, kinetics, and ZnO/MoO powder ratio. Additionally, the incidence of the pretreatment step of the ZnO and MoO powders under different atmospheres (air, Ar or Ar/H flow) was analyzed.

Influence of Quenching on the Opto-Electronic Properties of F:SnO Layers.

For many opto-electronic applications, F:SnO materials must benefit from high transparency, high conductivity, and high mechanical strength even after quenching. The purpose of this study was to investigate the influence of quenching on the opto-electronic properties of the F:SnO layers synthesized at high temperature on Si C O-coated soda-lime glass by atmospheric chemical vapor deposition. The morphology, structure, and composition of the layers were studied before and after quenching in air- and oxygen-rich atmospheres at 670 °C.

Toward Simplified Electrochromic Devices Using Silver as Counter Electrode Material.

Novel design of electrochromic devices (ECDs) known for their ability to modify optical properties under an applied voltage, based on a minimization of the number of layers is reported. The use of a metallic electrode, playing the role of both the conductive layer and the counter electrode, allows us to simplify the assembly of a commonly five-layer battery-type device to four-layer ECD. Further minimization of the number of layers is achieved using a conductive and electrochromic material.

The nitrogen concentration effect on Ce doped SiON emission: towards optimized Ce for LED applications.

Ce-Doped SiON films are deposited by magnetron reactive sputtering from a CeO target under a nitrogen reactive gas atmosphere. Visible photoluminescence measurements regarding the nitrogen gas flow reveal a large emission band centered at 450 nm for a sample deposited under a 2 sccm flow. Special attention is paid to the origin of such an emission at high nitrogen concentration.

Modified silver nanowire transparent electrodes with exceptional stability against oxidation.

We report an easy method to prepare thin, flexible and transparent electrodes that show enhanced inertness toward oxidation using modified silver nanowires (Ag NWs). Stabilization is achieved through the adsorption of triphenylphosphine (PPh3) onto the Ag NW hybrid dispersions prior to their 2D organization as transparent electrodes on polyethylene terephtalate (PET) films. After 110 days in air (20 °C) under atmospheric conditions, the transmittance of the PET/Ag NW/PPh3 based films is nearly unchanged, while the transmittance of the PET/Ag NW-based films decreases by about 5%.

A tris(triazolate) ligand for a highly active and magnetically recoverable palladium catalyst of selective alcohol oxidation using air at atmospheric pressure.

High efficiency and selectivity, easy magnetic recovery and recycling, and use of air as the oxidant at atmospheric pressure are major objectives for oxidation catalysis in terms of sustainable and green processes. A tris(triazolyl) ligand, so far only used in copper-catalyzed alkyne azide cycloadditions, was found to be extremely efficient in SiO2 /γ-Fe2 O3 -immobilized palladium complexes. It was characterized by inductively coupled plasma (ICP) analysis, transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), energy-dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectra (XPS) and found to fulfill the combined conditions for the selective oxidation of alcohols to aldehydes and ketones.

Core-level photoemission spectra of Mo0.3Cu0.7Sr2ErCu2Oy, a superconducting perovskite derivative. Unconventional structure-property relationships.

Detailed studies of the electronic states for Mo(0.3)Cu(0.7)Sr(2)ErCu(2)Oy samples with different oxygen contents are presented here.

RGD surface functionalization of the hydrophilic acrylic intraocular lens material to control posterior capsular opacification.

Posterior Capsular Opacification (PCO) is the capsule fibrosis developed on implanted IntraOcular Lens (IOL) by the de-differentiation of Lens Epithelial Cells (LECs) undergoing Epithelial Mesenchymal Transition (EMT). Literature has shown that the incidence of PCO is multifactorial including the patient's age or disease, surgical technique, and IOL design and material. Reports comparing hydrophilic and hydrophobic acrylic IOLs have shown that the former has more severe PCO.

Efficient and magnetically recoverable "click" PEGylated γ-Fe2O3-Pd nanoparticle catalysts for Suzuki-Miyaura, Sonogashira, and Heck reactions with positive dendritic effects.

The engineering of novel catalytic nanomaterials that are highly active for crucial carbon-carbon bond formations, easily recoverable many times, and biocompatible is highly desirable in terms of sustainable and green chemistry. To this end, catalysts comprising dendritic "click" ligands that are immobilized on a magnetic nanoparticle (MNP) core, terminated by triethylene glycol (TEG) groups, and incorporate Pd nanoparticles (PdNPs) have been prepared. These nanomaterials are characterized by transmission electron microscopy (TEM), high-resolution TEM, inductively coupled plasma analysis, Fourier transform infrared spectroscopy, X-ray photoelectron spectra and energy-dispersive X-ray spectroscopy.

Surface modification of polymers treated by various fluorinating media.

Fluorination processes of polymer surfaces are able to lead to drastic modifications of the surface properties without changing the bulk characteristics of the virgin material. In this paper, two types of polymers, i.e.

Stabilisation of carbon-supported palladium nanoparticles through the formation of an alloy with gold: application to the Sonogashira reaction.

Oh my Gold! Gold atoms stabilise catalytically active palladium nanoparticles when engaged in an alloy heterogenised on carbon. The increased durability makes the Pd-Au/C catalyst more recyclable than the gold-free Pd/C catalyst for the Sonogashira reaction.

Poly(acrylic acid)-block-poly(vinyl alcohol) anchored maghemite nanoparticles designed for multi-stimuli triggered drug release.

Original core/corona nanoparticles composed of a maghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug delivery system (DDS) application. This kind of DDS aims to combine the advantage of stimuli-responsive polymer coating, in order to regulate the drug release behaviours under different conditions and furthermore, improve the biocompatibility and in vivo circulation half-time of the maghemite nanoparticles. Drug loading capacity was evaluated with methylene blue (MB), a cationic model drug.

Rapid hydrothermal synthesis of VO2 (B) and its conversion to thermochromic VO2 (M1).

The present study provides a rapid way to obtain VO2 (B) under economical and environmentally friendly conditions. VO2 (B) is one of the well-known polymorphs of vanadium dioxide and is a promising cathode material for aqueous lithium ion batteries. VO2 (B) was successfully synthesized by rapid single-step hydrothermal process using V2O5 and citric acid as precursors.

Influence of nanohelical shape and periodicity on stem cell fate.

Microenvironments such as protein composition, physical features, geometry, and elasticity play important roles in stem cell lineage specification. The components of the extracellular matrix are known to subsequently assemble into fibrillar networks in vivo with defined periodicity. However, the effect of the most critical parameter, which involves the periodicity of these fibrillar networks, on the stem cell fate is not yet investigated.

Peptide immobilization on polyethylene terephthalate surfaces to study specific endothelial cell adhesion, spreading and migration.

To control specific endothelial cell (EC) functions, cell adhesive RGDS, EC specific REDV and YIGSR peptides, and angiogenic SVVYGLR sequences were covalently immobilized onto polyethylene terephthalate (PET) surfaces for the purpose of cell culture. X-ray photoelectron spectroscopy, atomic force microscopy, fluorescence microscopy and contact angle measurement were employed for characterization of surface modifications. The peptide density on PET surfaces was evaluated by fluorescence microscopy.

A new route towards nanoporous TiO2 as powders or thin films from the thermal treatment of titanium-based hybrid materials.

Calcination of cyclopentadienyltitanium-based organic-inorganic hybrid materials at 450-500 °C led to the formation of anatase titanium dioxide as white powders consisting of a porous network of aggregated nanoparticles, the nanoporosity detected being related to the inter-particle space. Depending on the calcination temperatures, the surface area of the titanium dioxide particles varied from 65 to 158 m(2) g(-1).

Dual lithium insertion and conversion mechanisms in a titanium-based mixed-anion nanocomposite.

The electrochemical reaction of lithium with a vacancy-containing titanium hydroxyfluoride was studied. On the basis of pair distribution function analysis, NMR, and X-ray photoelectron spectroscopy, we propose that the material undergoes partitioning upon initial discharge to form a nanostructured composite containing crystalline Li(x)TiO(2), surrounded by a Ti(0) and LiF layer. The Ti(0) is reoxidized upon reversible charging to an amorphous TiF(3) phase via a conversion reaction.

Low-temperature UV processing of nanoporous SnO₂ layers for dye-sensitized solar cells.

Connection of SnO₂ particles by simple UV irradiation in air yielded cassiterite SnO₂ porous films at low temperature. XPS, FTIR, and TGA-MS data revealed that the UV treatment has actually removed most of the organics present in the precursor SnO₂ colloid and gave more hydroxylated materials than calcination at high temperature. As electrodes for dye-sensitized solar cells (DSCs), the N3-modified 1-5 μm thick SnO₂ films showed excellent photovoltaic responses with overall power conversion efficiency reaching 2.

Fabrication and superhydrophobic behavior of fluorinated microspheres.

We describe the preparation of fluorinated microspheres by precipitation polymerization and their use to fabricate superhydrophobic surfaces. For that purpose, two different approaches have been employed. In the first approach, a fluorinated monomer (either 4-fluorostyrene or 2,3,4,5,6-pentafluorostyrene) was added to the initial mixture of monomers constituted by styrene (S) and divinylbenzene (DVB).