Patterning and photolumine scent properties of perovskite-type organic/inorganic hybrid luminescent films by soft lithography

Perovskite-type organic/inorganic hybrid layered compound (C6H5C2H4NH3)(2)PbI4 was synthesized. The patterning Of (C6H5C2H4NH3)(2)PbI4 thin films on silicon substrate was realized by the micromolding in capillaries (MIMIC) process, a kind of soft lithography. Bright green luminescent stripes with different widths (50, 15, 0.8 mum) have been obtained. The structure and optical properties Of (C6H5C2H4NH3)(2)PbI4 films were characterized by X-ray diffraction (XRD), UV/Vis absorption and photoluminescence excitation and emission spectra, respectively. It is shown that the organic-inorganic layered (C6H5C2H4NH3)(2)PbI4 film was c-axis oriented, paralleling to the substrate plane. Green exciton emission at 525 nm was observed in the film, and the explanations for it were given.

Synthesis, electrocatalytic properties and crystal structure of a new organic-inorganic hybrid constructed from dodecamolybdophosphoric acid and benzotriazole

A new compound, (C6H6N3)(7)((PMo12O40)-O-m)(PMo(v)Mo(11)(m)O40) (.) 2CH(3)CH(2)OH (.) 5H(2)O, was synthesized and characterized by means of elemental analyses, IR spectroscopy, H-1 NMR spectroscopy and single crystal X-ray diffraction. This is the first example of benzotriazole-polyoxometalates species. The compound crystallized in a triclinic space group P (1) over bar with a = 1. 8378 (4) nm. b = 1. 9078 (4) nm. c = 2.1037 (4) nm. alpha = 63.41 (3)degrees. beta = 64.31 (3)degrees. gamma = 68.38 (3)degrees. V = 5.803 (2) nm(3). Z = 2. R-1 = 0.0486, wR(2) = 0.1357. The X-ray crystallographic study showed that the crystal structure was constructed by electrostatic interactions and hydrogen bonds between dodecamolybdophosphorate anions and protonated benzotriazole cations. The electrochemical behavior and the reduction of nitrite and hydrogen peroxide clectrocatalyzed by the title compound were studied.

Photoluminescence of organic-inorganic hybrid SiO2 xerogels

Organic-inorganic hybrid SiO2 xerogels were prepared by the sol-gel method under various preparation conditions and compositions by using tetraethoxysilane (TEOS), (3-aminopropyl) triethoxysilane (A-PS), (3-glycidoxypropyl) trimethoxysilane (GPS), organic acid (CH3COOH) and inorganic acids (HCl, HNO3, H2SO4) as the main precursors. Luminescence and FT-IR spectra were used to characterize the resulted hybrid SiO2 xerogels. The result of FT-IR spectrum shows that the xerogels are composed of non-crystalline -Si-O-Si- networks containing some organic groups such as -NH, -CH and -OH. Under the excitation of 365 nm, all the hybrid xerogels exhibit strong luminescence in the blue region, but the emission intensity and position depend on the starting precursor compositions to a large extent. Suitable amount of polyethylene glycol (PEG500 and PEG10000) in the hybrid xerogels can enhance the emission intensity. Additionally, the emission intensity of the hybrid xerogels increases with heat treatment temperature in the range of ambient to 200degreesC, and vacuum condition is also able to enhance the emission intensity.

An organic-inorganic hybrid ultrathin film: preparation and characterization of copper phthalocyanine derivative-ferric oxide nanoparticles

A nanoparticulate ferric oxide-copper tris(2,4-di-tert-amylphenoxy)-8-quinolinolylphthalocyanine hybrid ultrathin film was constructed from alternate layers by the Langmuir-Blodgett technique. The composition, morphology and structure of the film were studied by X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, atomic force microscopy, small-angle X-ray diffraction, visible spectroscopy and polarized UV-Vis spectroscopy. All the above analyses suggest that the thin film is a kind of one-dimensional superlattice, composed of organic and inorganic components. The XPS data reveal that the nanoparticulate ferric oxide exists as an alpha-Fe2O3 phase in the films. Gas-sensing measurements show that the hybrid LB film has very fast response-recovery characteristics towards 2 ppm C2H5OH vapor.

Hydrothermal synthesis and structural characterization of a novel organic-inorganic hybrid compound {[Cu(2, 2 '-bpy)(2)](2)-Mo8O26}

A novel organic-inorganic hybrid compound {[Cu (2, 2'-bpy)(2)](2)Mo8O26} has been hydrothermally Synthesized and structurally characterized by single-crystal X-ray diffraction. The compound crystallizes in the orthorhombic space group, Pna2(1), with a=2.4164 (5), b=1.8281 (4), c=1.1877 (2) nm, V=5.247(2) nm(3), Z=4, and final R-1=0.0331, wR(2)=0.0727. The structure consists of discrete {[Cu(2,2'-bpy)(2)](2)Mo8O26} clusters, constructed from a beta -octamolybdate subunit[Mo8O26](4-) covalently bonded to two [Cu(2,2'-bpy)(2)](2+) coordination complex cations via bridging oxo groups. In addition, the spectroscopic properties and thermal behavior of this compound have been investigated by spectroscopic techniques (UV-vis, IR, Raman and EPR spectra) and TG analysis.

Luminescent properties of organic-inorganic hybrid monoliths containing rare-earth complexes

Transparent organic-inorganic hybrid monoliths containing rare-earth complexes (Eu(TTA)(3)Phen, Tb(Sal)(3)) were prepared via the sol-gel technique. It could be observed by transmission electron microscopy that the fluorescent particles are distributed in the matrix at the microscopic level. The matrix is composed of organic-inorganic semiinterpenetrating networks, i.e., PHEMA-SiO2 system. The fluorescence emission spectra of samples are similar to those from corresponding powdered Eu(III) and Tb(III) complexes, and the half-widths of the strongest bands are less than 10 nm, which indicates that the monolith exhibits high fluorescence intensity and color purity. Furthermore, the fluorescence spectra exhibit no obvious change with decreasing nanoparticle size of the rare-earth complex. The fluorescence lifetimes of samples are longer than pure Eu(III), Tb(III) complexes, respectively. Samples irradiated with an UV lamp (365 nm) are still transparent but become bright red and green in color due to fluorescence of Eu(III) and Tb(III) complexes. (C) 2000 Elsevier Science B.V. All rights reserved.

Confined crystallization behavior of PCL in organic-inorganic hybrid system

poly(epsilon-caprolactone) (PCL) and silica (SiO2) organic-inorganic hybrid materials have been synthesized by sol-gel approach and the crystalline behavior of PCL in the silica networks has been investigated by differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). The degree of PCL crystallinity in the PCL/SiO2 hybrid networks reduces with the increase of SiO2 content. PCL is in an amorphous state when the concentration of PCL is lower than 40wt% in the hybrid materials. The melting points of PCL in the networks are lower than that of pure PCL,but they almost have a same value. WAXD results show that when the PCL weight percentage is higher than 40wt% in the hybrid samples,part of PCL can crysatllize and the PCL crystallites are almost in a same size. That means the crystalline movement of PCL molecular chains is strictly confined by the porous gel. The crystalline PCL in the hybrid samples is relatively free from the composition of the materials, because the crystallization temperature and melting point of PCL of the samples are almost equal,and the crystalline PCL of different samples has the same crystalline structure and the same crystallite sizes L-110 and L-200, that means the crystalline part of PCL in the hybrid samples is unperturbed and the porous silica gel gives enough space for PCL to crystallize into the same crystalline structure and the same size crystallites.

Synthesis and luminescence properties of organic-inorganic hybrid thin films doped with Eu(III)

In this study, silica-based transparent organic-inorganic hybrid films were prepared by the sol-gel method. Tetraethoxysilane and 3-(trimethoxysilyl)propyl methacrylate were used as the inorganic and organic compounds, respectively. Lanthanide complexes [Eu(phen)(2)]Cl-3 were incorporated into the organically modified silicates (ORMOSIL) and the luminescence properties of the resultant hybrid films (ORMOSIL:[Eu(phen)(2)]Cl-3) were characterized. The relative quantum efficiency was observed higher and the lifetimes were longer in hybrid films than those in pure silica films. Furthermore, thermal stability of hybrid films incorporating various concentration of Eu(III) complex was studied. (C) 2001 Elsevier Science B.V. All rights reserved.

Amperometric glucose biosensor based on sol-gel organic-inorganic hybrid material

A new type of sol-gel organic-inorganic hybrid material was developed and used for the production of biosensors. This material is composed of silica sol and a grafting copolymer of poly(vinyl alcohol) with 4-vinylpyridine. It prevents the cracking of conventional sol-gel-derived glasses and eliminates the swelling of the hydrogel. The optimum composition of the hybrid material was first examined, and then glucose oxidase was immobilized in this matrix to demonstrate its application. The characteristics of the biosensor were studied by cyclic voltammetry and chronoamperometry. The biosensor exhibited a series of good properties: high sensitivity (600 nA mmol(-1)L(-1)), short response time (11 s) and remarkable long-term stability in storage (at least 5 months). In addition, the characteristics of the second-generation biosensor with the use of tetrathiafulvalene as a mediator mere discussed.

Lead(II) chloride ionic liquids and organic/inorganic hybrid materials - a study of chloroplumbate(II) speciation

A range of chloroplumbate(II) organic salts, based on the two cations, 1-ethyl-3-methylimidazolium and trihexyl(tetradecyl) phosphonium, was prepared by ionothermal synthesis. Depending on the structure of the organic cation and on the molar ratio of PbCl2 in the product,.PbCl2, the salts were room-temperature ionic liquids or crystalline organic/inorganic hybrid materials. The solids were studied using Raman spectroscopy; the crystal structure of [C(2)mim]{PbCl3} was determined and shown to contain 1D infinite chloroplumbate(II) strands formed by edge-sharing tetragonal pyramids of pentacoordinate (PbCl5) units. The liquids were analysed using Pb-207 NMR and Raman spectroscopies, as well as viscometry. Phase diagrams were constructed based on differential scanning calorimetry (DSC) measurements. Discrete anions: [PbCl4](2-) and [PbCl3](-), were detected in the liquid state. The trichloroplumbate(II) anion was shown to have a flexible structure due to the presence of a stereochemically-active lone pair. The relationship between the liquid phase anionic speciation and the structure of the corresponding crystalline products of ionothermal syntheses was discussed, and the data were compared with analogous tin(II) systems.

Porous organic-inorganic hybrid aerogels based on Cr3+/Fe3+ and rigid bridging carboxylates

A general method to prepare organic-inorganic hybrid aerogels has been presented. A series of organic-inorganic hybrid aerogels were successfully produced from 3d trivalent transition metals (Cr3+, Fe3+) and bridging carboxylic acids. Gelation of the Cr(III) gels was achieved by heating the precursor solution to temperatures above 80 degrees C, which is in sharp contrast to usual supramolecular gels. Among a range of ligands used, highly porous aerogels could be prepared from rigid carboxylate, e.g. 1,4-benzenedicarboxylate and 1,3,5-benzenetricarboxylate. The porous aerogels can be described as a coherent, rigid spongy network of continuous nanometre-sized particles, which is significantly different from the usual fibrous network of supramolecular gels. The aerogels have tunable porous structures with micro-and mesoporosity depending on their reactant concentrations. Their surface areas, pore volumes, and average pore sizes were analysed by using nitrogen sorption, and the accessibility of the pores to bulky molecules was also evaluated. It represents a strategy to prepare hybrid materials with large porosity utilising structurally simple building blocks as precursors.

Low optical loss planar waveguides prepared in an organic-inorganic hybrid system

HfO2-(3-glycidoxipropil)trimethoxisilane (GPTS) planar waveguides were prepared by a sol-gel route. A stable sol of Hafnia nanocrystals was prepared and characterized by photon correlation spectroscopy and high resolution transmission electron microscopy. The suspension was incorporated in GPTS host and the resulting sol was deposited on borosilicate substrates by the spin coating technique. Optical properties such as refractive index, thickness, number of propagating modes, and attenuation coefficient were measured at 632.8, 543.5, and 1550 nm by the prism coupling technique as a function of the HfO2 content. (C) 2000 American Institute of Physics. [S0003-6951(00)03348-9].