Preparation and properties of polyimide films codoped with barium and titanium oxides

Polyimide hybrid films containing bimetalic compounds were obtained by codoping poly(amic acid) with a barium and titanium precursor prepared from BaCO3, Ti(OBu)(4), and lactic acid followed by casting and thermal curing. FTIR, WAXD, and XPS measurements showed that barium and titanium precursor could be transformed to BaTiO3 at a temperature above 650 degreesC, while the mixed oxides were only found in hybrid films. The measurements of TEM and AFM indicated a homogeneous distribution of inorganic phase with particle sizes less than 50 nm. The hybrid films exhibited fairly high thermal stability, good optical transparency, and promising mechanical properties. The incorporation of 10 wt % barium and titanium oxide lowered surface and volume electrical resistivity by 2 and 5 orders, respectively, increasing dielectric constant from 3.5 to 4.2 and piezoelectric constant from 3.8 to 5.2 x 10(-12) c/N, relative to the nondoped polyimide film.

Template-free, surfactantless route to fabricate In(OH)(3) monocrystalline nanoarchitectures and their conversion to In2O3

In this work, a one-dimensional microrod-based three-dimensional flowerlike indium hydroxide (In(OH)(3)) structure was fabricated, without any templates or surfactants, using a well-known hydrothermal approach at a non-high temperature. In2O3 with similar morphology was formed by annealing In(OH)3 precursors and was characterized by Raman spectrum and photoluminescence (PL) spectrum in detail.

Macroscopic single-crystal tubes assembled with porous supramolecular architecture of water-soluble calixarene and phenanthroline

Single-crystal tubular products on the millimetre scale have been synthesized from water-soluble calixarene and phenanthroline in the presence of lanthanides by a hydrothermal method, in which the extended structures contain some 1D infinite channels.

Facile sonochemical synthesis of CePO4 : Tb/LaPO4 core/shell nanorods with highly improved photoluminescent properties

A simple, efficient and quick method has been established for the synthesis of CePO4:Tb nanorods and CePO4:Tb/LaPO4 core/shell nanorods via ultrasound irradiation of inorganic salt aqueous solution under ambient conditions for 2 h. The as-prepared products were characterized by means of powder x-ray diffraction (PXRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction ( SAED), x-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectra and lifetimes. TEM micrographs show that all of the as-prepared cerium phosphate products have rod-like shape, and have a relatively high degree of crystallinity and uniformity. HRTEM micrographs and SAED results prove that these nanorods are single crystalline in nature. The emission intensity and lifetime of the CePO4:Tb/LaPO4 core/shell nanorods increased significantly with respect to those of CePO4: Tb core nanorods under the same conditions. A substantial reduction in reaction time as well as reaction temperature is observed compared with the hydrothermal process.

Systematic synthesis and characterization of single-crystal lanthanide phenylphosphonate nanorods

Using low-temperature hydrothermal methods, nanoscale lanthanide phenylphosphonates species with different morphologies, namely, nanoparticles and nanorods, have been systematically synthesized. The possible growth mechanism of these nanorods was discussed. X-ray diffraction, transmission electron microscopy, electron diffraction, and photoluminescence spectra were used to characterize these materials. The photoluminescent properties of EU(O3PC6H5)(HO3PC6H5) and La0.91EU0.09(O3PC6H5)(HO3PC6H5) nanorods were discussed.

Synthesis of neodymium hydroxide nanotubes and nanorods by soft chemical process

A facile soft chemical approach using cetyltrimethylammoniurn bromide (CTAB) as template is successfully designed for synthesis of neodymium hydroxide nanotubes. These nanotubes have an average outer diameter around 20 nm, inner diameter around 2 nm, and length ranging from 100 to 120 nm, high BET surface area of 495.71 m(2) g(-1). We also find that neodymium hydroxide nanorods would be obtained when CTAB absented in reaction system. The Nd(OH)(3) nanorods might act as precursors that are converted into Nd2O3 nanorods through dehydration at 550 degrees C. The nanorods could exhibit upconversion emission characteristic under excitation of 591 nm at room temperature.

Synthesis and photoluminescence of Y2O3 : RE3+ (RE = Eu, Tb, Dy) porous nanotubes templated by carbon nanotubes

Y2O3:RE3+ (RE = Eu, Tb, Dy) porous nanotubes were first synthesized using carbon nanotubes as template. The morphology of the coated precursors and porous Y2O3:Eu3+ nanotubes was determined by scanning electron Microscopy (SEM) and transmission electron microscopy (TEM). It was found that the coating of precursors on carbon nanotubes (CNTs) is continuous and the thickness is about 15 nm, after calcinated, the Y2O3:Eu3+ nanotubes are porous with the diameter size in the range of 50-80 nm and the length in micrometer scale. X-ray diffraction (XRD) patterns confirmed that the samples are cubic phase Y2O3 and the photoluminescence studies showed that the porous rare earth ions doped nanotubes possess characteristic emission of Eu3+, Tb3+, and Dy3+. This method may also provide a novel approach to produce other inorganic porous nanotubes used in catalyst and sensors.

STUDIED ON THE SIMULTANEOUS SPECTROPHOTOMETRIC DETERMINATION OF INORGANIC MULTICOMPONENT SYSTEMS .3. DETERMINATION OF MICROAMOUNTS OF TUNGSTEN, MOLYBDENUM AND TITANIUM

The absorption spectra of W, Mo and Ti-phenylfluorone cetyltrimethylammonium bromide complexes and the optimum conditions for the simultaneous spectrophotometric determination of microamounts of W, Mo and Ti were studied. In order to examine the effect of the errors of calibration matrix on the analytical resulte, the approach of selecting the analytical wavelengths was investigated and the comparison of computation results between AKC method (the matrix representation of Beer-Lambert's Law) and ...

Hybrid bulk heterojunction solar cells from a blend of poly(3-hexylthiophene) and TiO2 nanotubes

Hybrid bulk heterojunction solar cells based on blend of poly(3-hexylthiophene) (P3HT) and TiO2 nanotubes or dye(N719) modified TiO2 nanotubes were processed from solution and characterized to research the nature of organic/inorganic hybrid materials. Compared with the pristine polymer P3HT and TiO2 nanoparticles/P3HT solar cells, the TiO2 nanotubes/P3HT hybrid solar cells show obvious performance improvement, due to the formation of the bulk heterojunction and charge transport improvement. A further improvement in the device performance can be achieved by modifying TiO2 nanotube surface with a standard dye N719 which can play a role in the improvement of both the light absorption and charge dissociation. Compared with the non-modified TiO2 nanotubes solar cells, the modified ones have better power conversion efficiency under 100 mW/cm(2) illumination with 500W Xenon lamp. (C) 2008 Elsevier B. V. All rights reserved.

Stone-Wales defects created by low energy recoils in single-walled silicon carbide nanotubes

The defect creation at low energy events was studied using density functional theory molecular dynamics simulations in silicon carbide nanotubes, and the displacement threshold energies determined exhibit a dependence on sizes, which decrease with decreasing diameter of the nanotubes. The Stone-Wales (SW) defect, which is a common defect configurations induced through irradiation in nanotubes, has also been investigated, and the formation energies of the SW defects increase with increasing diameter of the nanotubes. The mean threshold energies were found to be 23 and 18 eV for Si and C in armchair (5,5) nanotubes. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3238307]

Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in-situ formed lanthanide complexes

Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film.

Europium complexes immobilization on titania via chemical modification of titanium alkoxide

We report a facile strategy to tether lanthanide complexes to organic-inorganic hybrid titania materials via sol-gel processing by employing chemically modified titanium alkoxide as the precursor where the organic ligand sensitizing the luminescence of lanthanide ions is bonded to titanium.

Preparation and characterization of Gd2O3:Eu3+ luminescence nanotubes

The size controllable Gd2O3:Eu3+ luminescence nanotubes were successfully prepared using a simple method by coating gadolinium compounds on the carbon nanotubes and then firing the carbon nanotubes. The morphology of the obtained Gd2O3:Eu3+ nanotubes was determined by transmission electron microscopy (TEM). It was found that the obtained nanotubes have the outer diameters of similar to 100 nm, the inner diameters of similar to 50 nm, and the lengths of several tens of microns. The sizes of Gd2O3:Eu3+ nanotubes can be easily controlled by changing the reaction times and the concentration of reactants.

Metal nanomaterials and carbon nanotubes - synthesis, functionalization and potential applications towards electrochemistry

This review focuses on the synthesis, assembly, surface functionalization, as well as application of inorganic nanostructures. Electrochemical and wet- chemical methods are demonstrated to be effective approaches to make metal nanostructures under control without addition of a reducing agent or protecting agent. Owing to the unique physical and chemical properties of the nano-sized materials, novel applications are introduced using inorganic nanomaterials, such as electrocatalysis, photoelectricity, spectrochemistry, and analytical chemistry.