Ultrafine nanoparticles conglomerated alpha-Fe2O3 nanospheres were synthesized by laser irradiation of Fe (CO)(5) in acetone. As-prepared products were characterized by transmission electron microscopy, scanning electron microscopy and X-ray diffraction analysis techniques. Such obtained alpha-Fe2O3 nanospheres were used as gas-sensing materials, which exhibit good selectivity, fast response and excellent cycle performance to ethanol molecules. (C) 2017 Elsevier B.V. All rights reserved.

Moving target imaging (MTI) plays an important role in practical applications.How to capture dynamic images of the targets with high qualities has become a hot point of research in the field of MTI.In order to improve the reconstruction quality,a new MTI model based on compressed sensing (CS) is proposed here,by using a sampling protocol of the row-scanning together with a motion measurement matrix constructed by us.It is proved by the simulation and the experimental results that a relatively high quality can be achieved through this approach.Furthermore,an evaluation criterion of reconstructed image is introduced to analyze the relationship between the imaging quality and the moving speed of the target.By contrast,the performance of our algorithm is much better than that of traditional CS algorithm under the same moving speed condition.As a result,it is suggested that our imaging method may have a great application prospect in the earth observation of unmanned aerial vehicles,video monitoring in the product line and other fields.

Pure and Ti-doped WO3 thin films prepared by RF (radio-frequency) magnetron at room temperature were determined by XRD, Raman and SEM to analyze the micro-structure and the morphology of the films. In addition, electrochemical workstation and UN-Vis-NIR spectrophotometer were used to measure their cycling stability and optical property. Research results showed that Ti doping had little interference with the surface morphology and optical constants, but the film crystallization temperature could be increased by Ti doping. Electrochemical test results showed that Ti doping could improve reversibility of ion injection and extraction, and improve cycling performance of films. Meanwhile, the switching speed and optical modulation performance of films were enhanced. In detail, the switching time of colored and bleached states were shortened from 9.8 s and 3.5 s to 8.4 s and 2.7 s, respectively. Therefore, Ti doped WO3 thin films has better electrochromic properties.

The core/shell structure was formed by GO self-assembled with amine-functionalized commercial ZnO (CZO) and preparative hexagonal ZnO (HZO), respectively. Graphene-coated CZO and HZO were obtained after being reduced in Ar at 500 degrees C. The mechanism of the coating procedure was investigated by measuring their respective zeta potential values. Our characterizations demonstrate that graphene on HZO has better quality and fewer layers. An obvious band gap decrease of ZnO was observed for coating with graphene. Photoluminescence spectra of ZnO@graphene core/shell composites display the fluorescence quenching property, which indicates its good application prospect in optoelectronics, photocatalytic and other fields. (C) 2016 Elsevier B.V. All rights reserved.

The monoclinic phase (M phase) VO2 film is prepared on quartz glass substrate by a model MSP-3200 three-target co-sputter coater with RF magnetron reactive sputtering. The optical properties in incident energy ranges of 0.5-3.5 eV (350-2500 nm) and 0.083-0.87 eV (1400-15000 nm) of VO2 film are investigated by spectroscopic ellipsometry with variable temperature attachment. The good results are determined point by point with the three Lorentz harmonic oscillator dispersion models in the range of 0.5-3.5 eV and four Gaussion harmonic oscillator dispersion models in the range of 0.083-0.87 eV in the state of semiconductor below the transition temperature, while adding seven Lorentz harmonic oscillator dispersion models in the high temperature metallic state film results in the characteristic absorption peaks. The results show that the refractive index of the semiconductor state of VO2 film is maintained at maximum 3.27 and extinction coefficient k is close to zero in the near infrared-mid infrared, which is due to the fact that the absorption of semiconductor thin film in the VIS-NIR range is derived from the free carrier absorption and d(//) orbital of the semiconductor film has less electron density. The refractive index n of high temperature metallic state VO2 film has an obviously increasing trend in the near infrared-the mid infrared which is larger than the refractive index of the semiconductor state when the incident light energy is 0.45 eV. Extinction coefficient k increases rapidly in the near infrared, which is because the density of free carrier increases in the range of 0.5-1.62 eV and electron transition absorption augments within the V3d band. When the incident energy less than 0.5 eV, k value changes gently in the film because free carrier concentration and flow rates are stable.

Mg(OH)2 flakes composited on GO nanosheets as triggered by the colloidal electrostatic self-assembly in an liquid laser ablation process. The as-synthesized composite presented excellent adsorption performance for MB and heavy metal ions.

The monoclinic phase (M phase) VO2 film and W-doped M phase VO2 film were prepared on quartz substrate by a model MSP-3200 three targets co-sputter coater with RF magnetron reactive sputtering. The optical properties in the wavelength range of 350–2500 nm of VO2 film and W-doped VO2 film were investigated by spectroscopic ellipsometry with variable temperature attachment. The ellipsometric parameters φ and Δ were fitted by the Lorentz harmonic oscillator dispersion model combining with effective medium approximation model. The results show that the optical constants n, k of W-doped VO2 film vary with wavelength, compared to pure phase VO2 film, and the refractive index n of the W-doped VO2 film is less than that of the pure phase VO2 film. However, the extinction coefficient k of W-doped VO2 film is greater than that of pure phase VO2 film. The doping of W increases both the packing density and concentration of free carriers in VO2 film.

Ultrafine carbon nanodots can be obtained through simple combustion of small molecules with stable blue luminescence bands.

We represent a rational sandwich composite structure consisting of polyaniline, amorphous TiO2, and a graphene oxide network as an anode material for lithium-ion batteries with a high rate capability and long cycle life.

A colloidal approach was developed to immobilize magnetic ZnFe2O4 onto simultaneously reduced GO toward the degradation of dyes under visible-light irradiation.

Intense scientific efforts have been focused on the exploration of the unusual physical and chemical properties of colloidal nanoparticles (NPs). Here, surfactant-free ablated bismuth colloidal species showing distinctive advantages of high reactivity and reducibility were generated by laser-ablating metal Bi in deionized water. They can further react with water molecules and display self-assembly behaviour to form Bi(OH)(3) nanowires at ambient condition. Interestingly, under aging at 60 degrees C or light irradiation, Bi-based colloids will tend to react and self-assemble into phases of Bi2O3 and Bi2O4 nanocrystals. Furthermore, various bismuth-containing compounds, such as bismuth oxyhalides (BiOX, X = Cl, Br, I), Ag/Au/Pt-modified BiOCl, BiVO4, and Bi2WO6 semiconductors were also successfully produced through the reaction of ablated bismuth colloidal species with corresponding chemical reagents or with ablated V and W colloidal species. These synthetic strategies proved that LAL-induced colloidal species are capable of serving as unique chemical precursors. The relatively slow, dynamic species-by-species reaction greatly favours controllable growth and tunable nanostructure compared with the conventional rapid ion-by-ion reaction. Importantly, this growth route provides more underlying insights regarding the growth and assembly mechanisms of nanocrystals without influence from additional chemical ions or surfactants.

Hematite is an important material used in water splitting and lithium-ion battery electrodes. Electronic conductivity and the visible light-absorption ability of hematite are enhanced by doping impurity ions into the hematite lattice and achieving an appropriate hematite nanostructure. This paper reports the simultaneous doping and growth of tin (Sn)-doped hematite crystalline films on a conducting substrate. The crystalline films were prepared by a hydrothermal process. Laser ablation in liquid induced SnOx colloidal nanoparticles, which were used as the doping source. The obtained compacted films were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and UV-vis spectrophotometry analyses. XRD results showed the Sn-doped alpha-Fe2O3 crystalline nanoparticles had dominant active (110) planes. Annealing affected the photoelectrochemical (PEC) performance of the Sn-doped hematite photoanode, and the photocurrent density of the photoanode annealed at 750 degrees C for 2 h reached the highest value at 0.48 mA cm(-2) (at 1.23 V vs. reversible hydrogen electrode). Electrochemical impedance spectroscopy measurements revealed that the charge-transfer resistance of Sn-doped hematite films decreased after the annealing treatment. The improved crystallinity and the preferred (110) plane in the doped crystalline film are favor of the migration of electrons and holes to electrode surfaces, the removal of deleterious surface states and increase of the free electron density, which should contribute to the enhanced PEC performance.

Numerous efforts have been made to integrate nanorods into 3D ordered multifunctional architectures. Herein, we report a rational design and the successful fabrication of a novel chestnut-like Fe3O4@C@ZnSnO3 core-shell hierarchical structure. Reactive Zn and Sn colloids obtained using laser ablation in liquids were used as non-ion precursors to intentionally grow ZnSnO3 nanorods onto the surfaces of core-shell Fe3O4@C particles under solvothermal conditions. The core-shell hierarchical structures were analyzed by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray analysis (EDX), X-ray diffraction, and a superconducting quantum interference device magnetometer (Quantum Design MPMS). The results showed that the Fe3O4@C particles served as nucleation sites for the oriented growth of ZnSnO3 nanorods on the surfaces of the carbon layer. The synthesized core-shell composite exhibited cyclic photocatalytic ability toward the degradation of 2,5-dichlorophenol model molecules because of the compact assembly of the magnetic Fe3O4 core, the active ZnSnO3 photocatalyst, and a protective carbon layer.

Quantum-sized SnO2 nanocrystals can be well dispersed on reduced graphene oxide (rGO) nanosheets through a convenient one-pot in situ reduction route without using any other chemical reagent or source. Highly reactive metastable tin oxide (SnOx) nanoparticles (NPs) were used as reducing agents and composite precursors derived by the laser ablation in liquid (LAL) technique. Moreover, the growth and phase transition of LAL-induced SnOx NPs and graphene oxide (GO) were examined by optical absorption, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy and high-resolution transmission electron microscopy. Highly dispersed SnOx NPs can also prevent rGO from being restacked into a multilayer structure during GO reduction. Given the good electron transfer ability and unsaturated dangling bonds of rGO, as well as the ample electrocatalytic active sites of quantum-sized SnO2 NPs on unfolded rGO sheets, the fabricated SnO2-rGO nanocomposite exhibited excellent performance in the non-enzymatic electrochemical detection of glucose molecules. The use of LAL-induced reactive NPs for in situ GO reduction is also expected to be a universal and environmentally friendly approach for the formation of various rGO-based nanocomposites.

A TiO2/BiOCl composite with a hierarchical structure was constructed by grafting BiOCl nanosheets onto a film of TiO2 nanotube arrays. The structure and morphology were characterised using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV-vis diffuse reflection spectroscopy, and Raman spectroscopy. The activity of the composite photocatalyst for the photodegradation of methyl orange and pentachlorophenol was higher than that of either single-phase TiO2 or BiOCl. The improved photodecomposition performance can be mainly attributed to the enhanced separation efficiency of photo-induced electrons and holes, both at the interface and in the two semiconductors. The proposed grafting strategy for the formation of this hybrid photocatalyst can also be applied to other semiconductor candidates resulting in improved photo-electrochemical properties.