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Copper oxide nanoparticles (CuO NPs) are attractive owing to their size- and shape-dependent properties, as well as their diverse applications. Therefore, the synthesis of environmentally friendly CuO NPs using low-toxicity reagents remains significant. In this study, a benign wet-chemical process was applied to synthesize CuO NPs in an alcohol-water mixture, employing copper acetate as the precursor and sodium oleate as the surfactant. Multiple experimental parameters, including water content, the molar ratio of sodium oleate to copper acetate, types of alcohols, and reaction temperature, were investigated to examine their effects on the formation and structures of the resulting products. Results from X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed the monoclinic crystalline structure of CuO NPs with an ultra-small size of less than 3 nm. The size of CuO NPs can be easily adjusted by altering the water content, the molar ratio of precursor to surfactant, and other factors. The as-synthesized CuO NPs exhibited significantly enhanced antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). [ABSTRACT FROM AUTHOR]

Wet‐chemical synthesis refers to the bottom‐up chemical synthesis in solution, which is among the most popular synthetic approaches towards functional two‐dimensional (2D) materials. It offers several advantages, including cost‐effectiveness, high yields,, precious control over the production process. As an emerging family of 2D materials, elemental 2D materials (Xenes) have shown great potential in various applications such as electronics, catalysts, biochemistry,, sensing technologies due to their exceptional/exotic properties such as large surface area, tunable band gap,, high carrier mobility. In this review, we provide a comprehensive overview of the current state‐of‐the‐art in wet‐chemical synthesis of Xenes including tellurene, bismuthene, antimonene, phosphorene,, arsenene. The current solvent compositions, process parameters utilized in wet‐chemical synthesis, their effects on the thickness, stability of the resulting Xenes are also presented. Key factors considered involves ligands, precursors, surfactants, reaction time, temperature. Finally, we highlight recent advances, existing challenges in the current application of wet‐chemical synthesis for Xenes production, provide perspectives on future improvement. [ABSTRACT FROM AUTHOR]

Fluoro-aluminates with pyrochlore-type structures such as Cs2KAl3F12 & Cs2NaAl3F12 could have very useful industrial applications but despite of having much significance, very less exploration on these kinds of compounds has been accomplished. Although some experiments related to luminescence studies on Ce3+ activated phosphors have been achieved on these fluorides long ago, since then very less considerable work on investigating such compounds was done so far. Therefore further work has been carried out by adding rare-earth gadolinium (Gd) as an activator in these complexes. Gadolinium in its trivalent form showed encouraging luminescence results. Additionally, the effect of dopant concentration on photoluminescence intensities has been studied. Decay characteristics showed long lifetimes (in ms) that vary with Gd3+ concentrations. Also, respective values for quantum efficiency (Ø)% and non-radiative rates (AnR) have been evaluated. Phase-purity was confirmed with the help of XRD and Rietveld analysis. [ABSTRACT FROM AUTHOR]

Abstract Combining material big data with artificial intelligence constitutes the fourth paradigm of material research. However, the sluggish development of high‐throughput (HT) experimentation has resulted in a lack of experimentally verified and validated material data, which has become the bottleneck of data‐driven material research. Wet‐chemical synthesis has the benefits of low equipment cost and scalability, but traditional wet‐chemical techniques are time‐consuming and ineffective at disclosing the interrelationships between synthesis, compositions, structures, and performance. Constructing a HT workflow in wet‐chemical synthesis is crucial to achieving the preparation of multidimensional materials and establishing the composition–structure–synthesis–performance relationships of functional materials for diverse applications. In this review, the most recent development in HT wet‐chemical synthesis techniques for material research are analyzed in depth. Additionally, the application of HT wet‐chemical synthesis in the fabrication of advanced hydrogels and catalysts is demonstrated through illustrative instances. Finally, this review suggests possible paths for enhancing the efficiency of HT experimentation and data acquisition in order to facilitate more effective material discovery.

In the past decades, metal-containing nanomaterials have attracted increasing interests owing to their intriguing physicochemical properties and various promising applications. Recent research has revealed that the phase of metal-containing nanomaterials could significantly affect their properties and functions. In particular, nanomaterials with amorphous phase, which possess long-range disordered atomic arrangements, and the amorphous/crystalline heterophase nanostructures comprised of both amorphous and crystalline phases, have exhibited superior performance in various applications, e.g., catalysis and energy storage. In this review, a brief overview of the recent progress on the wet-chemical synthesis and applications of amorphous and amorphous/crystalline heterophase metal-containing nanomaterials has been provided. Subsequently, on the basis of different categories of metal-containing nanomaterials, including metals, metal alloys, and metal compounds, their synthetic routes and promising applications will be highlighted. Finally, current challenges and some personal perspectives in this emerging research field will be proposed. [ABSTRACT FROM AUTHOR]

Multi-feature based nano- (and micro-) materials are highly promising candidates for mechanical energy harvesting. The impregnation of the nanocrystals in a polymer matrix modifies the electrical characteristics of a composite film; in consequence, it becomes a multifunctional composite membrane. Herein, we report cuboctahedron zinc ferrite (ZnFe2O4) microparticles in a polydimethylsiloxane (PDMS) (ZnFe2O4@PDMS)-based composite film for mechanical energy harvesting. Several composite films are prepared at different thicknesses and weight percentages (wt%). The composite film having a thickness of 750 μm and 4 wt% generates a maximum open-circuit voltage (Voc), short-circuit current (Isc) and power of 60 V, 7.4 μA and 97 μW, respectively, by applying the contact-and-separation mode of a triboelectric nanogenerator. In addition, the film generates non-separation Voc of 800 mV and Isc of 580 nA. Eventually, the composite films were employed for tactile sensing applications. Versatile property-based ZnFe2O4@PDMS films can be further explored for hybrid device applications also. [ABSTRACT FROM AUTHOR]

Precursor powders for BaCe0.2Zr0.7Y0.1O3-δ(BCZY27) ceramics were synthesized by a modified Pechinimethod and calcined at 900°C for 12 h. The calcined BCZY27 powders were milled in eccentric and in high energy mill with the addition of 2 and 4mol% ZnO as sintering aid. The effects of milling and sintering aids on the sinterability and electrical conductivity were studied. The linear shrinkage in thermomechanical analyses started at 1050°C for the BCZY27 with 4mol% ZnO processed in eccentric mill. Theoretical density above of 90%TD was obtained for the BCZY27 milled with 4mol% ZnO and sintered at 1400°C for 4h. X-ray diffraction analysis of the BCZY27 ceramics sintered at 1400°C confirmed the presence of BaCe0.2Zr0.7Y0.1O3-δ and Y0.4Ce0.6O1.8 phases. The incorporation of Zn into perovskite lattice leads to the secondary phase formation. SEM and EDS analyses confirmed the presence of Y0.4Ce0.6O1.8 phase. The sintering was assisted by BaO-ZnO eutectic, which was reflected by the increase of activation energy values for grain boundary conduction. The milling processing did not affect the conductivity properties. The obtained BCZY27 dense sample has conductivity of 7.60 × 10−3 S/cm at 500°C.

Abstract The research work aimed to explore a serial of facile methods to obtain low‐cost, flexible, and high‐performance CdS/CdSe QDSSCs. The flexible photoanode was prepared on the ITO/PEN substrate by blade coating. In order to improve the bonding performance between different layers of photovoltaic devices, the introduction of additives in the precursor slurry and the rapid annealing after blade coating were adopted. The flexible CdS/CdSe QDSSCs deliver energy conversion efficiency over 3%. When the tert‐butanol additive was introduced, the conversion efficiency of the flexible device was as high as 3.49%. Meanwhile, flexible devices also showed excellent bending stability. When hydrochloric acid additives were introduced, the energy conversion efficiency retention rate of flexible CdS/CdSe QDSSCs was 72.7%, which showed great application potential.

Two-dimensional (2D) metal nanomaterials have gained ever-growing research interest owing to their fascinating physicochemical properties and promising application, especially in the field of electrocatalysis. In this review, we briefly introduce the recent advances in wet-chemical synthesis of 2D metal nanomaterials. Subsequently, the catalytic performances of 2D metal nanomaterials in a variety of electrochemical reactions are illustrated. Finally, we summarize current challenges and highlight our perspectives on preparing high-performance 2D metal electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] The very recent development of highly selective techniques making possible the synthesis and experimental characterization of subnanometric (subnanometer-sized) metal clusters (even single atoms) is pushing our understanding far beyond the present knowledge in materials science, driving these clusters as a new generation of quantum materials at the lower bounds of nanotechnology. When the size of the metal cluster is reduced to a small number of atoms, the d -band of the metal splits into a subnanometric d -type molecular orbitals network in which all metal atoms are inter-connected, with the inter-connections having the length of a chemical bond (1–2 Å). These molecular characteristics are at the very core of the high stability and novel properties of the smallest metal clusters, with their integration into colloidal materials interacting with the environment having the potential to further boost their performance in applications such as luminescence, sensing, bioimaging, theranostics, energy conversion, catalysis, and photocatalysis. Through the presentation of very recent case studies, this Feature Article is aimed to illustrate how first-principles modelling, including methods beyond the state-of-the-art and an interplay with cutting-edge experiments, is helping to understand the special properties of these clusters at the most fundamental level. Moreover, it will be discussed how superfluid helium droplets can act both as nano-reactors and carriers to achieve the synthesis and surface deposition of metal clusters. This concept will be illustrated with the quantum simulation of the helium droplet-assisted soft-landing of a single Au atom onto a titanium dioxide (TiO 2) surface. Next, it will be shown how the application of first-principles methods have disclosed the fundamental reasons why subnanometric Cu 5 clusters are resistant to irreversible oxidation, and capable of increasing and extending into the visible region the solar absorption of TiO 2 , of augmenting its efficiency for photo-catalysis beyond a factor of four, also considering the decomposition and photo-activation of CO 2 as a prototypical (photo-) catalytic reaction. Finally, I will discuss how the modification of the same material with subnanometric Ag 5 clusters has converted it into a "reporter" of a surface polaron property as well as a novel two-dimensional polaronic material. [ABSTRACT FROM AUTHOR]

Ultrafine pure and cobalt doped SnO2-δ nanocrystals (Sn1-xCoxO2-δ, 0 ≤ x ≤ 0.05) were synthesized by microwave-assisted hydrothermal method. The as-prepared nanocrystals have single phase tetragonal rutile structure. With increase of Co content (x > 0.01), Co entered into SnO2 lattice in mixed Co2+/Co3+ state. Pronounced blue shift of the band gap with cobalt doping originated from the combined effect of quantum confinement and Burnstain-Moss shift. Raman and photoluminescence study revealed oxygen deficient structure of SnO2-δ for which the prevalent defects are in the form of in-plane oxygen vacancies. Co-doping induced decrease of in-plane oxygen vacancy concentration and luminescence quenching. SnO2-δ exhibited significantly better photocatalytic activity under UV light irradiation, than Co-doped samples due to better UV light absorption and increased concentration of in-plane oxygen vacancies which, as shallow donors, enable better electron-hole separation and faster charge transport.

A simple wet-chemical synthesis method was developed to fabricate Zinc oxide micro-rod clusters. The synthesis process involved the rapid dilution of a zinc-bearing alkaline solution at 150°C in a convection oven on indium tin oxide (ITO) substrates. The synthesis was carried out by immersing an unseeded ITO substrate in a mixture of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and hexamethylenetetramine ((CH2)6N4) aqueous solution. The obtained sample was annealed at 400°C for 2 h. The structural, morphological and optical properties of the synthesized ZnO microstructures were investigated by X-ray diffraction, scanning electron microscopy and ultraviolet-visible spectroscopy, respectively. The ZnO rod clusters are hexagonal phase of the wurtzite structure. The crystal grain sizes of the films were found to be 72.6, 84.3 and 66.3 nm for the (100), (002) and (101) crystal planes, respectively. The optical bandgap of the ZnO was determined to be 3.147 eV. [ABSTRACT FROM AUTHOR]

Abstract Semiconductor nanomaterial-based epitaxial heterostructures with precisely controlled compositions and morphologies are of great importance for various applications in optoelectronics, thermoelectrics, and catalysis. Until now, various kinds of epitaxial heterostructures have been constructed. In this minireview, we will first introduce the synthesis of semiconductor nanomaterial-based epitaxial heterostructures by wet-chemical methods. Various architectures based on different kinds of seeds or templates are illustrated, and their growth mechanisms are discussed in detail. Then, the applications of epitaxial heterostructures in optoelectronics, catalysis, and thermoelectrics are described. Finally, we provide some challenges and personal perspectives for the future research directions of semiconductor nanomaterial-based epitaxial heterostructures.

The research work aimed to explore a serial of facile methods to obtain low‐cost, flexible, and high‐performance CdS/CdSe QDSSCs. The flexible photoanode was prepared on the ITO/PEN substrate by blade coating. In order to improve the bonding performance between different layers of photovoltaic devices, the introduction of additives in the precursor slurry and the rapid annealing after blade coating were adopted. The flexible CdS/CdSe QDSSCs deliver energy conversion efficiency over 3%. When the tert‐butanol additive was introduced, the conversion efficiency of the flexible device was as high as 3.49%. Meanwhile, flexible devices also showed excellent bending stability. When hydrochloric acid additives were introduced, the energy conversion efficiency retention rate of flexible CdS/CdSe QDSSCs was 72.7%, which showed great application potential. [ABSTRACT FROM AUTHOR]

Near-field enhanced mid-infrared light-matter interactions via metallic plasmonic antennae (PA) have attracted much attention but are inevitably limited by the detuning between their narrow band and the broad applied spectral range. Here, we develop a new low-temperature incubation synthetic method to acquire uniform Ag microparticles (MPs) with numerous hotspots. Their plasmonic band is remarkably extended by the plasmonic coupling of numerous hotspots and covers the entire mid-infrared range (400-4000 cm -1 ). Hence, the almost complete molecular fingerprint of 4-mercaptobenzonitrile was successfully probed for the first time via resonant surface-enhanced infrared absorption (rSEIRA), and the rSEIRA spectra of different essential amino acids were further detected and exhibit a high spectral identification degree assisted by machine learning. This work changes the inertia perception of "narrow band and large size but small hotspot area" of mid-infrared metallic PA and paves the way for the ultrasensitive mid-infrared optical sensing.

The wet-chemical technique has been widely applied in material synthesis. In recent years, high throughput (HT) technique has shown its potential in parallel synthesis and the investigation of synthesis parameters. However, traditional ways of HT parallel synthesis require costly equipment and complex operating procedures, restricting their further applications. In this paper, we prepared a cost-effective and timesaving microfluidic-based composition and temperature controlling platform to carry out HT wet-chemical synthesis in a facile and automated workflow. The platform uses a microfluidic chip to generate 20–level concentration gradients of the two reagents and uses 100–channel reactor arrays for wet-chemical synthesis with 5–level temperature gradients. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) were applied to characterize Co–Ni bimetallic powder materials synthesized under 100 different reaction conditions. X-ray photoelectron spectroscopy (XPS) was conducted to confirm the oxidation state of the products. This platform not only enables one-step determination of the minimum reaction temperature required for a wet-chemical system but also provides a significant increase in efficiency compared with the traditional wet-chemical approach. The microfluidic-based composition and temperature controlling platform shows promise in facile, efficient, and low-cost HT wet-chemical synthesis of materials.

IrO 2 and RuO 2 are known as two of the best catalysts for the oxygen evolution reaction (OER) in acidic electrolyte. It is reported that RuO 2 has higher OER catalytic activity, while IrO 2 possesses better electrochemical stability during the OER process in acid. Therefore, many combined strategies have been proposed to utilize the advantages of both IrO 2 and RuO 2 catalysts in water electrolysis applications. In this article we describe how, by tuning the wet-chemical synthesis process in which the Ir precursor is added after the synthesis of RuO 2 nanoparticles (NPs) (two-step), the Ru 0.5 Ir 0.5 O 2 NPs have been synthesized to improve the OER catalytic activity in both acidic and alkaline media. In detail, the specific OER activity of the Ru 0.5 Ir 0.5 O 2 NPs (with a particle size of ca. 10 nm) is 48.9 μA cm−2 at an overpotential ŋ = 0.22 V (vs. RHE) and 21.7 μA cm−2 at ŋ = 0.27 V (vs. RHE) in 0.1 M HClO 4 and 0.1 M KOH, respectively. These values are higher than those for the one-step (Ir 0.5 +Ru 0.5)O 2 NPs (obtained by contemporaneously adding both Ru and Ir precursors), which are 19.5 and 15.5 μA cm−2 at the same measuring conditions, respectively. Additionally, with more IrO 2 component distributed on the particle surface, the two-step Ru 0.5 Ir 0.5 O 2 NPs show better OER catalytic stability than RuO 2 NPs. Image 1 • Two-step synthesis yields higher number of surface-Ir atoms on mixed Ru 0.5 Ir 0.5 O 2 NPs. • The particle size of Ru 0.5 Ir 0.5 O 2 NPs is relatively small, about 10 nm. • The high OER catalytic activities of two-step Ru 0.5 Ir 0.5 O 2 NPs are achieved. • Two-step Ru 0.5 Ir 0.5 O 2 NPs possess better OER stability than one-step synthesized NPs. [ABSTRACT FROM AUTHOR]

Nanorods of Ce0.85La0.15O1.925 (CLO) have been synthesized using a wet-chemical route and characterized by thermal analysis, phase, crystal structure, microstructure and electrical conductivity. Nanorods have been stabilized by adding binary eutectic mixture of Li2CO3 and Na2CO3. This hinders the grain growth of Ce0.85La0.15O1.925 nanorods. Cubic fluorite structure of ceria has been detected by X-ray diffraction. A sharp increase in the conductivity has been observed at a certain temperature, corresponding to superionic transition at the interfaces. This composition shows the highest conductivity, 1.14 × 10−1 S/cm at 500 °C with activation energy of conduction 0.19 eV. This value is about three orders of magnitude higher than that of Ce0.85La0.15O1.925 (2.02 × 10−4 S/cm at 500 °C) nanoparticles prepared by auto-combustion route. [ABSTRACT FROM AUTHOR]

Coal is one of the most abundant natural carbonaceous materials. This paper reports a novel oxidative chemical method for the synthesis of high-value carbon dots (CDs) from cheap and abundant low-quality high‑sulfur coals for use in high-end applications. These CDs were synthesized by using wet-chemical ultrasonic stimulation-induced process which is environmentally facile and less drastic compared to other chemical methods of production of CDs. The sizes of the synthesized CDs from different types of coal samples were estimated to be in the range of 1–4 nm, 1–6 nm, 2–5 nm, and 10–30 nm. The quantum yield (QY) of the CDs was determined and it was found to be around 3–14%. For high-end field application, the CDs were further tested for toxicity and were reported to be safe for environmental and biological applications. The cell image analysis under the fluorescence microscope further indicated that the synthesized CDs could be used as a promising bio-compatible material for optical-imaging as well as bio-imaging. The CDs showed promising fluorescent sensing property and can be utilized as a good probe for silver ion detection/sensing. The CDs is also found to be a promising reagent for silver nanoparticles synthesis. The results provide a new avenue for large-scale synthesis of CDs. Unlabelled Image • Simple synthetic wet-chemical production of carbon dots from low-quality coal • Blue-fluorescence emitting, biocompatible, and safe carbon dots • Promising fluorescent for bio-imaging and sensing of Ag+ ions [ABSTRACT FROM AUTHOR]

Graphical abstract F-containing TiO 2 nanoparticles prepared by one-pot wet chemical methods show improved photocatalytic activity. Highlights • F-TiO 2 nanoparticles were synthesized using simple wet chemical route. • The produced F-TiO 2 nanoparticles with tens of nanometers had a hierarchical structure. • Photocatalytic activity of F-TiO 2 showed the improved behavior compare with H-TiO 2. • The possible mechanism for improved photocatalytic activity due to surface fluorine was discussed. Abstract Two types of TiO 2 nanoparticles: i) fluorine-containing TiO 2 (F-TiO 2) and ii) fluorine-free TiO 2 (H-TiO 2) nanoparticles, were prepared through a simple, scalable wet-chemical synthesis process, and a comparative study of their photocatalytic properties was conducted. This facile process begins with a one-pot precipitation process at 90 °C, followed by heat treatment at 600 °C for 1 h in air, resulting in hierarchical, sphere-like, mesoporous structures composed of primary nanoparticles. The microstructural features and crystallographic structures of both types of nanoparticles were systematically investigated by X-ray diffraction, thermogravimetric/differential thermal analysis, X-ray photoelectron spectroscopy, N 2 physical adsorption-desorption, field emission scanning electron microscopy, and transmission electron microscopy analyses. The photocatalytic activities were also evaluated by measuring the degradation of MB. The F-TiO 2 nanoparticles showed enhanced photocatalytic activity compared to H-TiO 2 , which can be attributed to adsorbed fluorine on the surface which leads to various positive effects on the photocatalytic degradation reactions. [ABSTRACT FROM AUTHOR]

With the dual objective of investigating the site preferences of larger sized activator ions and to append luminescence property to the perovskite structured RbZnF 3 , doping of manganese(II), cerium(III), europium(III) and terbium(III) ions (5 mol%) was carried out. Although cubic symmetry of RbZnF 3 was preserved for all the doped samples, site preference of rare-earth ions for the A-site Rb + leading to an inverse perovskite arrangement has been noticed from careful analysis of lattice parameters from refinement of powder X-ray diffraction data. Undoped RbZnF 3 exhibited rod-like morphology in the transmission electron microscopic image. In addition to an intense band around 230 nm assignable to the charge transfer from ZnF 3 − to Rb + , typical transitions of respective dopant ions were observed in their UV–visible spectra. The doped samples showed luminescence in blue, green and red regions and time decay experiments suggested uniform dispersion of them without any clustering effect. The lower phonon energy of RbZnF 3 matrix by virtue of the presence of heavier rubidium at the A-site together with its doping with rare-earth ions resulting in an inverse perovskite like arrangement could favour their utility in various practical applications. [ABSTRACT FROM AUTHOR]

The synthesis of efficient nanosized persistent luminescence materials remains a challenge for the community. Paradoxically, due to the dependence of the point lattice defects and the persistent luminescence efficiency, the control of the defect formation, favorable when the materials are prepared at high temperatures, normally leads to particle growth and sintering. In this work, efficient nanosized rare earth doped disilicates Sr 2 MgSi 2 O 7 :Eu 2+ ,Dy 3+ were synthesized via three different wet-chemical methods taking advantages of the microwave-assisted reduction process as a support step to produce high-quality polycrystalline materials. The crystallite size of the sample showed to be smaller when the decomposition temperature of the precursors is higher and close to the phase formation energy. The excitation VUV spectroscopy indicated that despite being nanocrystalline, the materials optical band gap has just a small difference compared one to another. The reduction of Eu 3+ to Eu 2+ was successfully obtained, since the f-d interconfigurational transitions of Eu 2+ 4f 6 5d 1 →4f 7 emission were observed in the blue region of the spectra. The persistent luminescence efficiency measured through its lasting decay time was close to the commercial materials references and with the advantage of having size control during the synthesis method that can lead to the size dependent applications of photonic materials. [ABSTRACT FROM AUTHOR]

Platelike alkaline niobates, which are an important class of templates for growing lead-free textured piezoceramic materials, are usually synthesized at temperatures greater than 900 °C from a melting process. We previously developed a hydrothermal route to niobate hydrate at temperatures above 100 °C and combined it with heat treatment to yield platelike niobate perovskite. In this contribution, we present the first report on near-room-temperature wet-chemical preparation of platelike potassium niobate (KN) and potassium sodium niobate (KNN) hydrate particles. Hexagonal-platelike KN-hydrate particles that were 1.5–4.0 μm wide and 0.1–0.35 μm thick were prepared via low temperature synthesis at 60 °C over a period of 24 h in a 9 mol/L KOH solution. Similarly, KNN hydrate particles with a hexagonal-platelike shape were prepared at 40 °C over a period of 48 h in 6 mol/L [OH − ]. Sodium dodecyl benzene sulfonate (SDBS) surfactant was added as a shape modulator. Calcining the KN hydrate particles at 500 °C for 2 h transformed the crystals to a stable perovskite phase while maintaining the platelike morphology. The low-temperature wet-chemical route to alkaline niobates is expected to lead to a low-cost scalable method for the mass production of platelike template particles in the field of high-performance lead-free piezoceramics. [ABSTRACT FROM AUTHOR]

Lanthanum-doped lead zirconate titanate (Pb 0.95 La 0.05 Zr 1−x Ti x O 3 ) with two different compositions, x=0.20 (PLZT20) and 0.80 (PLZT80), were successfully obtained by the oxidant peroxide method (OPM). This environmental friendly synthetic route showed to be very attractive to prepare lead based ferroelectric powders since no carbon or halides compounds were used. Tetragonal perovskite structure was observed for PLZT80 and rhombohedral perovskite for PLZT20, with single phase identified in the powders calcined at temperatures higher than 700 °C. Powders crystallized at 700 °C were used to produce ceramic samples that were sintered at 1000 °C for 2 h by conventional and microwaves techniques. The composition of the fractured surface of ceramics were quite close to the nominal molar composition, indicating that the OPM promotes the formation of materials with high compositional homogeneity and similar microstructures regardless the sintering method used. [ABSTRACT FROM AUTHOR]

Bismuth titanate with sillenite structure (Bi 12 TiO 20 ) was prepared at lower temperatures and shorter times using a modified oxidant peroxide method (OPM). Bi 12 TiO 20 was synthesized utilizing commercial Bi 2 O 3 and reactive titanium dioxide nanoparticles having peroxo-modified surfaces. Rather than depending on particle size, the reaction mechanism is related to the highly exothermic decomposition of peroxo groups, regardless the titanium source used, which locally releases a large amount of energy that can accelerate the reaction, similar to self-propagating high temperature routes (SHS). [ABSTRACT FROM AUTHOR]

The yttrium, iron and niobium doped-SrTiO 3 powders have been successfully fabricated by a modified low–temperature synthesis method from a polymer complex. The usage of strontium hydroxide precursor instead of conventional strontium nitrate or strontium carbonate provides to the possibility of significant decrease of annealing temperature. It allows to prepare a material with sphere-shape grains of nanometric size (15–70 nm). The results of thermal analysis indicate that the crystallization of precursor takes place at different stages. The product after heat treatment at 600 °C for 3 h in air was also characterized by X-Ray diffraction method (XRD) and Fourier transform – infrared spectroscopy (FT-IR). After the crystallization and the impurity removal process, a single-phase material was obtained in case of all analyzed samples. The morphology of obtained nano-powders was also studied by a scanning electron microscopy (SEM). It can be concluded, that this method allows obtaining a perovskite phase of a metal doped SrTiO 3 with nanometric particles. [ABSTRACT FROM AUTHOR]

We present a theoretical formalism which, for the first time, accounts for the nucleation, growth and/or redissolution of binary non-ideal solid-solutions, whether mineral or bimetallic, in solution. It yields the time evolution of all ion activities, together with the particle population characteristics: number, size and composition profile of particles as a function of time and of their time of nucleation. It is shown that depending on the Guggenheim parameter values which drive the non-ideality of the solid-solution, on the ratio of the solubility products of the end-members and on initial conditions, different scenarios of precipitation may take place, in which particles display composition profiles which may be smooth or discontinuous. An illustration of the characteristics of precipitation in the various scenarios is given, by simulations performed under some simplifying assumptions and qualitative predictions are made for the precipitation of some mineral solid solutions of geochemical interest. To our knowledge, this is the first time, in the fields of both geochemistry and metallic alloys, that these out-of-equilibrium precipitation processes of non-ideal solid-solutions are fully described. [ABSTRACT FROM AUTHOR]

The integration of ceramic powders in composite materials for bone scaffolds can improve the osseointegration process. This work was aimed to the synthesis and characterization of new collagen–hydroxyapatite/barium titanate (Coll–HA/BT) composite materials starting from barium titanate (BT) nanopowder, hydroxyapatite (HA) nanopowder and collagen (Coll) gel. BT nanopowder was produced by combining two wet-chemical approaches, sol–gel and hydrothermal methods. The resulting materials were characterized in terms of phase composition and microstructure by X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy. Moreover, the biocompatibility and bioactivity of the composite materials were assessed by in vitro tests. The synthesized BT particles exhibit an average size of around 35 nm and a spherical morphology, with a pseudo-cubic or tetragonal symmetry. The diffraction spectra of Coll–HA and Coll–HA/BT composite materials indicate a pronounced interaction between Col and the mineral phases, meaning a good mineralization of Col fibres. As well, the in vitro tests highlight excellent osteoinductive properties for all biological samples, especially for Coll–HA/BT composite materials, fact that can be attributed to the ferromagnetic properties of BT. [ABSTRACT FROM AUTHOR]

We propose a short review paper on the mainly adopted techniques for the production of metal nanoparticles in industrial and laboratory scale. The methods are grouped according to the wellknown classification in bottom-up and top-down schemes, with a particular emphasis on the operating conditions specifically adopted. Namely, some aspects concerning the experimental setup, the choice of precursors and reactants and the relevant technical advantages/limitations of the methods are discussed and compared in light of the most recent issues in matter of metal nanoparticles synthesis. [ABSTRACT FROM AUTHOR]

Bimetallic PdAu alloyed nanochain networks (PdAu NCNs) were facilely prepared by a simple wet-chemical method with the assistance of allantoin as the structure-directing agent and stabilizing agent. Allantoin played an important role in the formation of chain-like networks. The products were mainly characterized by transmission electron microscopy (TEM), high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy. The as-prepared PdAu NCNs had enlarged electrochemical active surface area, and displayed enhanced electrocatalytic activity toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR), showing higher resistance to poisoning CO-like intermediates in MOR and more positive onset potential in ORR as compared to commercial Pd black catalyst. This approach provides a promising route for large-scale preparation of desirable bimetallic catalysts with the assistance of small biomolecules. [ABSTRACT FROM AUTHOR]

ABSTRACT The property of high refractive index, low solubility in water as well as stability to high temperature variation of lanthanum phosphate (LaPO4) proved it was the most effective candidate for the production of display lamps, and plasma display panel devices and sensors. The morphological and nanostructural characteristics play a key role in the working efficiency of the luminescent material. These properties can be controlled by the synthesis method, which we have adopted in this paper. We have prepared LaPO4 nanoparticles at a relatively low temperature (110 ºC) in polyethylene glycol medium by using a wet chemical one-step synthesis. The phase composition and structural properties of the sample have been characterized by X-ray diffraction, Fourier transform infrared, transmission electron microscopy and the luminescent property by photoluminescence and thermoluminescence. The samples were well crystallized and the average crystallite size of 15 nm has been calculated for pure LaPO4 using the Debye-Scherrer equation. The result from heat-treated samples shows the phase combination and morphological structure of the powder depend on the annealing temperature. The heat treatment changes the structure of LaPO4 from cuboid rods to fine grains at about 600 °C. The emission spectrum of LaPO4 shows the broad emission band at 368 nm and shoulder at 465 nm with emission of blue color when monitored at an excitation wavelength at 256 nm. The stability of phosphor has been studied with respect to humidity, temperature, doping, doping concentration, γ-ray exposures, etc. The prepared nanosized phosphors were thermally stable and may be a promising blue phosphor for lighting technology as well as radiation dosimetry. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Abstract: Cerium activated yttrium aluminate with garnet structure Y3Al5O12:Ce3+ is used as yellow emitting phosphor for the manufacturing of white light emitting diodes (WLEDs) generating “cold white” illumination. The luminescent emission of WLEDs can be either red, or blue tuned by the partial substitution of Y3+ with Gd3+ and/or Al3+ with B3+, respectively. The paper presents our results referring to the preparation of (Y,Gd)3(Al,B)5O12:Ce3+ type phosphors by the wet chemical synthesis route – WCS, using the simultaneous reagent addition technique – SimAdd. In this respect, the Y/Gd–Al/B–Ce precursors were obtained by coprecipitation, from Y, Gd, Al, Ce nitrates, boric acid and urea solution. The precursor nano-powders were intimately mixed with NH4Cl (flux), and heat treated at 1200°C/2h in nitrogen atmosphere. Based on complementary investigations it can be seen that the phosphorus composition consists of a mixture of (Y,Gd)3Al5O12:Ce3+ and (Y,Gd)BO3:Ce3+. The photoluminescent, morphological and structural properties of the phosphor powders were investigated in relation with the Gd/Y or B/Al substitution. It is revealed that the WCS-SimAdd route can be used to synthesize a phosphor with modulated color, appropriate for the use in LED-type optoelectronic devices. [Copyright &y& Elsevier]

The integration of ZnO nanostructures in practical devices almost always takes advantage of wet-chemistry procedures which are largely inefficient in terms of energy, chemicals, time, length, and cost. For instance, in many cases the predeposition and annealing of a seed layer is required, which can also result in process-compatibility and functional issues. Forced flow, thermal convection, and localized heating may help, but can also introduce other difficulties. Here we demonstrate that heating the substrate by an adjacent temperature-controlled surface can naturally promote the ultra-efficient, convection-assisted, seed-less synthesis of high-density, vertically aligned ZnO nanowires on large areas. In particular, the sub-mm confinement of the high-temperature required for solution-growth can reduce the nanowire energetic-cost by orders of magnitude. As examples, we effortlessly grow with a single procedure high-density and long (up to several tens of μm) ZnO nanowires on silicon, gold, aluminium, and both the copper and the plastic of flexible printed circuit boards (PCBs). As proofs of concept, we show the unprecedentedly low-energy, easy and seed-less cointegration on a flexible PCB of a ZnO-nanowire piezotronic strain sensor with gauge factor around 1000. The proposed approach can be generalized to the solution-growth of other materials and can result in ultra-efficient depositions on a wide variety of substrates. [Display omitted] • Wet-chemical synthesis by heating the substrate with an adjacent surface. • Nanowire-energetic cost reduced by orders of magnitude. • Superior efficiency in terms of energy, chemicals, time, length, and cost. • Seed-less, high-density, long, vertically aligned ZnO nanowires on large areas. • Lowest energy, cheapest and easiest to fabricate piezotronic device ever reported. [ABSTRACT FROM AUTHOR]

Abstract: Europium activated yttrium aluminate (YAG:Eu) phosphors were synthesized using urea by wet chemical synthesis route. The luminescent behavior and the microstructural changes are monitored, depending on the amount of europium. The luminescent spectra of YAG:Eu phosphors possess four major emission bands in the range of 570–700nm with maxima situated at 592nm 598nm, 611nm and 631nm. The intensity ratio between the 611nm band as red component (5D0 → 7F2) and 592nm band as orange component (5D0 → 7F1) is discussed, in order to obtain information about the chemical surroundings of the luminescent centers and their symmetry. X-ray diffraction showed that the main crystalline phase of the phosphors is yttrium aluminum garnet Y3Al5O12 with cubic structure. Monoclinic Y4Al2O9 phase was also found as impurity. The effect of the europium content on the microstructural parameters is revealed. The luminescent characteristics depend strongly on the structural purity, activator concentration and incorporation of europium ions in the host lattice. Additional investigations as FT-IR, BET, ICP-OES were performed for a better understanding of the luminescent and structural characteristics of YAG:Eu phosphor. [Copyright &y& Elsevier]

Three types of precursors were prepared using the wet-chemical synthesis route, starting from yttrium-europium-aluminum nitrate solution and different precipitating agents (urea, oxalic acid, and ammonium carbonate). The precursors were fired at 1200 °C in nitrogen atmosphere in order to obtain europium-doped yttrium aluminate YAlO:Eu phosphor with garnet structure (YAG:Eu). The processes involved in the thermal decomposition of precursors and their composition were put in evidence using thermal analysis (TG-DTA) and FT-IR spectroscopy. The GA-DTA curves possess typical features for basic-oxalate, -nitrate, and -carbonates as formed with oxalic acid, urea, and ammonium carbonate, respectively. Correlation between the thermal decomposition steps, mass loss, and composition of gases evolved during the thermal treatment was established using TG-DTA-FT-IR coupling. It was found that the different composition of precursors reflects on the luminescent characteristics of the corresponding phosphors. Urea and ammonium carbonate lead to the formation of YAG type phosphors, with garnet structure and specific red emission. As for the oxalic acid, this precipitating agent generates a non-homogeneous powder that contains yttrium oxide as impurity phase. This phosphor is a mixture of YO:Eu, YAlO:Eu, and YAlO:Eu that explain the relative higher emission intensity. [ABSTRACT FROM AUTHOR]

This work reports fabrication of bistable memory switching devices employing wet-chemically synthesized ZnO nanoparticles with polymethyl methacrylate and poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] polymers. ZnO nanoparticle-embedded polymer layers were coated on conducting indium tin oxide (ITO) glasses using the spin-coating technique. Synthesized ZnO nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, x-ray diffraction, energy-dispersive x-ray, and photoluminescence studies. These ZnO particles are 20 nm to 30 nm in size with hexagonal structure. Switching and memory effects of the devices fabricated employing the ZnO nanoparticle-polymer composite films were investigated using current-voltage ( I- V) characteristics. The I- V measurements of both polymer devices showed electrical bistability. The ON to OFF current ratio of the bistable device was found to be ∼10. The observed current-time response showed good memory retention behavior of the fabricated devices. The carrier transport mechanism of the devices has been described on the basis of I- V experimental results and electronic structure. [ABSTRACT FROM AUTHOR]

Abstract: The magnetic and microwave properties of Ni nanospheres and conical nanorods have been investigated through experimental and theoretical methods. Ni nanospheres and conical nanorods have the same crystal structure and close particle size, whereas the remanence ratio, coercivity, dynamic permeability and microwave absorbing properties show great dependence on their shape. Ni conical nanorods self-assembled into urchin-like structure have higher natural resonance frequency due to the large shape anisotropy compared to the Ni nanospheres. Supposing random spatial distribution of magnetic easy axes and using the Landau–Lifshitz–Gilbert equation associated with the Bruggeman''s effective medium theory, we simulate the complex permeability of Ni nanoparticles, which agrees well with the experimental results. [Copyright &y& Elsevier]