Synthesis and structural characterization of tungsten disulfide nanomaterials

In this study, tungsten disulfide nanoparticles with different structure have been generated via a solid–gas reaction with tungsten oxide nanobundles as precursors. The structural features of the as-prepared tungsten disulfide nanomaterials were investigated via electron microscopy and selected area electron patterns (SAED) in detail. SAED pattern obtained from the tungsten disulfide particles with sheet-texture structure is discrete speckled rings consisting of numbers of diffraction spots, differing dramatically from those of tungsten disulfide nanorods and nanotubes. The formation of the unique tungsten disulfide sheet-texture particles should be attributed to both the morphological evolution of the tungsten oxide bundles and the sulphur diffusion during the oxide-to-disulfide conversion. This study may be helpful to investigate structurally other layered materials with different morphology.     

Synthesis,crystal growth and characterization of novel semiorganic nonlinear optical crystal: Dichlorobis(l-proline)zinc(II)

Single crystals of the semiorganic material, dichlorobis(l-proline)zinc(II) (DCBPZ), were grown from aqueous solution. The grown crystals were tested by single crystal X-ray diffraction, energy-dispersive spectrometry, FT-IR, UV–vis and TG–DTA. The structural prefection of the grown crystals has been analyzed by high-resolution X-ray diffraction (HRXRD) rocking curve measurements. The dielectric and mechanical behavior of the specimen was also studied. The SHG efficiency of DCBPZ is three times greater than that of KDP. Measuring transmittance of DCBPZ permitted the calculation of the refractive index n, the extinction coefficient K and both the real ?_r and imaginary ?_i components of the dielectric constant as functions of photon energy. The optical band gap of DCBPZ is 4.8 eV.     

纳米结构TiO2/SiO2的制备、结构与光催化性能

用自组装技术合成了纳米TiO2包覆的SiO2粒子.其中TiO2胶体通过溶胶-凝胶方法得到.讨论了不同晶型负载TiO2的合成条件及光催化性.样品经IR,SEM,XRD等进行表征.实验结果表明:SiO2粒子表面的纳米TiO2具有较好的均匀性;TiO2的含量随覆盖层的增加而增多;组装两层样品具有较大的比表面;经100℃干燥可得到不同晶型的纳米TiO2,且锐钛矿型含量较高的纳米TiO2组装粒子具有较好的光催化性能,     

一种具有光学特性的新型哌嗪衍生物晶体的合成与表征

以哌嗪（PQ）和马来酸酐（MAH）为原料,在较温和的条件下制备了一种新型哌嗪衍生物-4,4’-（1,4-哌嗪基）-2-（4-羰基-2-丁烯酸）,简称为PBBA。采用倒置相差显微镜、傅里叶红外吸收光谱（FT-IR）、高效液相色谱质谱联用仪（HPLC-EMS）、高精度原子力扫描电镜（AFM-IPC）等对其性能和结构进行了表征。结果表明PBBA晶体具有特异的光学性能和对称的分子结构。     

Synthesis,structure, and field-effect property of 2-(benzimidazol-2-yl) quinoline

A new active electronic material, 2-(benzimidazol-2-yl) quinoline (BIQ), has been synthesized and fully characterized. This compound exhibits field-effect carrier mobility and behaves as a p-type semiconductor (μ_FET=0.038 cm²/V s at V_DS=15 V). BIQ and its related imidazolylquinoline compounds may have possible application as active materials in organic thin film transistors.     

新型聚丙烯酸酯的制备与非线性光学性能

设计合成了一种含偶氮苯和取代苯乙炔基长共轭生色团的丙烯酸酯,并采用溶液聚合法合成了功能化的聚丙烯酸酯,利用FTIR、NMR等对化合物的结构进行了表征,证实得到了指定结构的化合物.利用z-scan技术对合成的聚丙烯酸酯的非线性光学性能进行了表征,对聚合物的非线性吸收进行拟合,计算得到非线性吸收系数β和三阶非线性系数x(3).     

Crystal structure and characterization of a novel organic optical crystal: 2-Aminopyridinium trichloroacetate

2-Aminopyridinium trichloroacetate, a novel organic optical material has been synthesized and crystals were grown from aqueous solution employing the technique of controlled evaporation. 2-Aminopyridinium trichloroacetate crystallizes in monoclinic system with space group P2₁/c and the lattice parameters are a = 8.598(5) Å, b = 11.336(2) Å, c = 11.023(2) Å, β = 102.83(1)° and volume = 1047.5(3) Å³. High-resolution X-ray diffraction measurements were performed to analyze the structural perfection of the grown crystals. Thermal analysis shows a sharp endothermic peak at 124 °C due to melting reaction of 2-aminopyridinium trichloroacetate. UV-vis-NIR studies reveal that 2-aminopyridinium trichloroacetate has UV cutoff wavelength at 354 nm. Dielectric studies show that dielectric constant and dielectric loss decreases with increasing frequency and finally it becomes almost a constant at higher frequencies for all temperatures. The negative nonlinear optical parameters of 2-aminopyridinium trichloroacetate were derived by the Z-scan technique.     

Synthesis,structure, growth and characterization of a novel organic NLO single crystal: Morpholin-4-ium p-aminobenzoate

The title compound, morpholin-4-ium p-aminobenzoate (MPABA)(C₄H₁₀NO⁺,C₇H₆NO₂^?), has been synthesized for the first time by the addition of morpholine with 4-aminobenzoic acid in equi-molar ratio and good quality single crystals have been grown by solution growth technique using methanol as a solvent. The molecular structure of the compound was solved and refined by Direct Methods using SHELXS97 and full-matrix least-squares technique using SHELXL97, respectively. MPABA crystallizes in a monoclinic system with unit cell parameters, a = 5.948(5) Å, b = 18.033(4) Å, c = 10.577(5) Å, β = 90.40(1)° and non-centrosymmetric space group Cc. The experimentally measured density and chemical compositions were found to be in good agreement with the theoretical values. The phases and functional groups of MPABA have been identified and confirmed through powder X-ray diffraction and Fourier transform infrared (FTIR) studies, respectively. The thermal stability and decomposition details were studied through TG/DTA thermograms. The UV–visible transmission spectra were recorded for the grown crystal and its NLO characteristic was explored by powder second harmonic generation (SHG) studies.     

TiO2纳米带制备、表征及光催化性能

采用简单的水热反应以及后续的热处理,制备了大量的TiO2纳米带。通过XRD、SEM、TEM以及UV-Vis对产物进行表征和分析,并以甲基橙作为目标降解物,对退火后的产物进行了光催化性能测试。结果表明,所制备的样品在600℃热处理3h后,样品为锐钛矿相与TiO2(B)相的混晶相。退火以后,带的形态保持较好,带宽约60nm。室温下,所制备的混晶TiO2对甲基橙具有良好的紫外光降解能力,60min后降解度达96%。     

ZnO nanocone arrays on self-assembled Zn2SnO4 base: synthesis, structure, growth mechanism and optical property

ZnO nanocone arrays on self-assembled Zn2SnO4 base were successfully synthesized via a thermal evaporation method of two-step temperature-rising. The as-prepared ZnO nanocone products had a well crystalline wurzite structure with symmetry about the growth direction along [0001]. Based on the calculation of the lattice misfit between different families of crystal planes of ZnO and Zn2SnO4, Stranski-Krastanow growth mode of ZnO nanocones was proposed in which the ZnO relaxing layer plays an important role. The orientation relationship of nanocone and base was also investigated. For the optical property of this nanocones-base system, a strong green fluorescence-emission at 523 nm was detected while the Zn2SnO4 base provides a defect peak at 486 nm which broadens the green emission band.     

Synthesis and characterization of a novel photocrosslinkable fluorinated poly(arylene ether) for optical waveguide

To improve its chemical resistance and mechanical stability, a novel fluorinated poly(arylene ether) bearing a photocrosslinkable chalcone group in the main chain was successfully synthesized by means of polycondensation between 4,4′-dihydroxychalcone and decafluorobiphenyl in N,N-dimethylacetamide in the presence of the excess anhydrous potassium carbonate. The structure of polymer was characterized by ¹H NMR and ¹⁹F NMR spectroscopies. The resulting polymer shows excellent solubility in common organic solvents, high glass transition temperature and good thermal stability. Crosslinking of the resulted polymer has been demonstrated by UV irradiation. Near-IR spectra of polymer film before and after UV irradiation show no absorption at the telecommunication wavelengths of 1310 and 1550 nm, demonstrating that the resulting polymer is good candidate material for optical waveguide application.     

Synthesis,optical and thermal characterization of novel thiazolyl heterocyclic azo dye

Thiazolyl heterocyclic azo dye and its metal (Ni²⁺, Co²⁺)–azo complexes were synthesized. Their structures were confirmed by elemental analysis, UV–VIS absorption spectra, FT-IR, ¹H NMR and MALDI-MS. The thermal properties of metal complexes were studied by DSC–TGA. The optical constants (complex refractive index N = n + ik) and thickness of the complex thin films on polished single-crystal silicon substrates were investigated on a scanning ellipsometer. Results indicate that thiazolyl metal–azo complexes possess good optical and thermal properties. They would be a promising recording medium candidate for NVD with the Super-resolution near field structure (Super-RENS) technology.     

Synthesis,crystal growth and characterization of nonlinear optical organic crystal: p-Toluidinium p-toluenesulphonate

p-Toluidinium p-toluenesulphonate (p-TTS) an organic nonlinear optical crystal has been grown from the aqueous solution by slow evaporation solution growth technique. Single crystal X-ray diffraction analysis reveals that p-TTS crystallizes in monoclinic crystal system. The structural perfection of the grown p-TTS single crystal has been analyzed by high-resolution X-ray diffraction rocking curve measurements. Fourier transform infrared spectral studies have been performed to identify the functional groups. The optical transmittance window and the lower cutoff wavelength of the grown crystals have been identified by UV–vis–IR studies. Birefringence of p-TTS crystal has been studied using channel spectrum measurement. The laser damage threshold value was measured using Nd:YAG laser. The second harmonic conversion efficiency of p-TTS has been determined using Kurtz powder technique. Thermo gravimetric and differential thermal analyses were used to study its thermal properties. Dielectric constant, dielectric loss and AC conductivity of the grown p-TTS single crystal has been studied.     

Synthesis,crystal growth and optical absorption of EuLiH3

The EuLiH₃ was synthesized by direct reaction between lithium metal, europium dihydride and hydrogen. Single crystals of EuLiH₃ ($\text{a}\text{=3.795}\text{A}\text{?}$) with well defined chemical purity were grown from the melt using the Stockbarger technique. At room temperature an optical absorption edge of 1.99eV was found which exhibits a red shift of 0.14eV upon cooling below the magnetic ordering temperature.     

Synthesis and characterization of WS2 nanotube supported cobalt catalyst for hydrodesulfurization

WS₂ nanostructures hold structural characteristics which suggest they will be suitable for heterogeneous catalysis in the hydrodesulfurization (HDS) process. In this work, WS₂ nanotubes (INT-WS₂) were coated with cobalt nanoparticles using electroless plating method. Prior to cobalt deposition, the nanotubes surface was activated using palladium seeding process. The deposited cobalt nanoparticles had hcp crystal structure and formed non-uniform layer on the nanotubes surface. The catalytic reactivity of the produced cobalt coated nanotubes toward thiophene decomposition was characterized by an atmospheric flow reactor. The coated nanotubes revealed good catalytic reactivity toward thiophene mineralization. Further, the adsorption kinetics of thiophene on coated INT-WS₂ was studied by thermal desorption spectroscopy (TDS). The cobalt coated system was found to be more catalytically active than the pristine INT-WS₂ system. This result is promising since further optimization of the nanofabrication process of the catalyst should increase the conversion rates even further.     

Phase structure and hydrogen absorption property of LaMg2Cu

LaMg₂Cu alloy was prepared by inductive melting and then was annealed at 723 K for 10 h in 0.1 MPa argon atmospheres. X-ray diffraction (XRD) and scanning electron microscopy (SEM) showed that the alloy consisted of LaMg₂Cu₂ phase, LaMg₃ phase and a few of unknown phases. The annealing treatment improved the equilibrium pressure and hydrogen absorption capacity of LaMg₂Cu alloy. The hydrogen absorption capacity of the as-cast and annealed alloys at 473 K were 2.86 and 3.33 wt.%, and the equilibrium pressure were 1 and 3 MPa, respectively. The enthalpy and entropy of LaMg₂Cu–H hydriding reaction were determined. LaMg₂Cu alloy could absorb hydrogen with rapid hydriding kinetics, the hydrogen absorption rate of LaMg₂Cu increased from 423 K to 498 K and the uptake time for hydrogen content to reach 90% of the maximum storage capacity for annealed alloy was less than 550 s at 498 K. The experimental curves of hydrogen absorption kinetics could be fitted with good accuracy by Jander equation. It suggested that the hydriding of LaMg₂Cu alloy was a three-dimensional diffusion-controlled process. And the activation energy and pre-exponential factor of LaMg₂Cu alloy were also calculated.     

Fabrication, characterization and optical property of CuI nanospheres

Single-crystal cuprous iodide semiconductor nanospheres were fabricated via a mild low-temperature solution route by using polyvinyl pyrrolidone as capping agent and the mixture of water and polyethylene glycol 400 as solvent. The structure, morphology, and properties of the products were characterized by powder X-ray diffraction, transmission electron microscopy, scanning electron microscopy, thermal gravimetry and photoluminescence spectrometry. The results showed that the products were CuI nanospheres of ca. 280-650 nm in diameter and were composed of quasi-trigonal particles of ca. 20-40 nm. The phase transformation temperature and the melting point of the products decreased by ca. 12 and 8 °C compared with the bulk CuI. The possible formation mechanism was discussed on the basis of experimental results.     

Synthesis, characterization and formation mechanism of single-phase nanostructure bredigite powder

Single-phase nanocrystalline bredigite powder was successfully synthesized by mechanical activation of talc, calcium carbonate, and amorphous silica powder mixture followed by annealing. Simultaneous thermal analysis (STA), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), dynamic light scattering (DLS),and Fourier transform infrared spectroscopy (FT-IR) techniques were employed to characterize various powders. Single-phase nanostructure bredigite powder with crystallite size of about 65 nm was synthesized by 20 h of mechanical activation with subsequent annealing at 1200 °C for 1 h. The bredigite formation mechanism was studied. During the formation process of nanostructure bredigite powder some intermediate compounds such as wollastonite (CaSiO₃), larnite (Ca₂SiO₄), merwinite (Ca₃MgSi₂O₈), and calcium magnesium silicate (Ca₅MgSi₃O₁₂) were formed. It was found that bredigite was not produced directly and that the formation of merwinite, enstatite and Ca₅MgSi₃O₁₂was unavoidable during the synthesis of bredigite.