The Photophysical Properties of Ruthenium Polypyridyl Complexes within a Sol-Gel Matrix

Tetraethoxysilane (TEOS) sol-gel monoliths impregnated with three different luminescent [Ru(L)₃]²⁺ complexes (where L = 2,2-bipyridine (bpy), 1,10-phenanthroline (phen), or 4,7-diphenyl,1,10-phenanthroline (dpp)) have been prepared. The photoluminescence properties of these complexes were followed as a function of time, as the sol-gel reactions proceeded. Clear differences were observed in the emission energies and the emission lifetimes of the complexes upon gel formation. These differences can be explained by the different extent of electrostatic interaction between the surface of the siloxane polymer and the immobilised complex.     

溶胶—凝胶法制备有机—无机纳米复合材料

溶胶－凝胶法以其温和的反应条件，尤其是低的反应温度成为有机－无机纳米复合材料制备的最有效的方法．本文根据合成路线的不同，分５个方面对用溶胶－凝胶法制备复合材料进行概要介绍．     

Optical Nonlinearity of Hybrid and Nanocomposite Materials Prepared by the Sol-Gel Method

In this paper the nonlinear refractive index, optical limiting effect, photoinduced and electroinduced second harmonic generation of dye-doped hybrid and nanoparticle-doped composite materials prepared by the sol-gel process have been reported. The origin of these nonlinear optical effects has been discussed.     

溶胶-凝胶工艺制备发光薄膜研究进展

本文综述了通过深胶－凝胶工艺制备发光薄膜的基本过程、薄膜的表征方法、发光薄膜的当前发展及应用情况。依据组成特点,对溶胶－凝胶法制备的发光薄膜乾地了分类阐述,并预言了今后该法制备发光薄膜的发展趋势。     

Preparation and Characterization of Novel Luminescent Sol-Gel Films Containing a RE3+ Carboxylic Acid Complex

RE³⁺ (Eu³⁺, Tb³⁺) complexes with carboxylic acid (salicylic acid and benzoic acid) were introduced into the sol, which was prepared by the hydrolysis of tetraethoxysilane (TEOS). A sol-gel luminescent thin film (SG-LTF) was then prepared by dispersing the sol onto a silica substrate by a spin coating method. Multi-layer luminescent thin films were prepared by repeating the same process. The luminescent spectra, fluorescence lifetime and thermal stability of the SG-LTFs were investigated. For the reason of comparison polyvinylbutyral (PVB) was added into a N,N-dimethylformamide (DMF) solution in which the comparative RE³⁺ carboxylic acid complexes were previously dissolved to form the DMF/PVB solution and the PVB luminescent thin film (PVB-LTF) was prepared. The results show that a broad excitation band indicates the formation of RE complexes in the solid SG-LTFs. RE ions, which are restrained in the silica matrix, present longer lifetimes and higher thermal stability than that in the PVB-LTF containing the corresponding pure complexes. The different doping concentration of RE (III) complexes in the SG-LTFs and the different change of the emission intensities with the heat treatment temperature in the sol-gel thin film and the sol-gel bulk gel were also discussed in this paper.     

溶胶-凝胶法合成(Ce, Tb)GdMgB5O10及其发光性质的研究

利用溶胶-凝胶法合成了纯的GdMgB5O10及GdMgB5O10：Ce^3 ，Tb^3 粉末；利用X射线衍射(XRD)、扫描电镜(SEM)、发光光谱等测试手段对GdMgB5O10以及GdMgB5O10：Ce^3 ，Tb^3 粉末的物相、形貌、发光性质等进行了研究。XRD和SEM结果表明溶胶-凝胶法适合制备GdMgB5O10，且在800℃焙烧时完成结晶，颗粒尺寸为200～300nm。发光光谱的测试表明：Tb^3 呈现其特征绿光发射，最强峰位于543nm，在GdMgB5O10：Tb^3 中，当236nm激发时其最佳掺杂摩尔分数为16％。通过光谱分析进一步证实了GdMgB5O10：Ce^3 ，Tb^3 中存在的能量传递过程为：Ce^3 将能量传递给Gd^3 ，然后能量在Gd^3 次晶格中经若干次迁移，最后被Tb^3 捕获。     

Fullerenes in Sol-Gel Materials

The family of fullerene molecules is composed of a large variety of compounds that have been synthesized following the discovery of C₆₀ in 1985. The chemistry of fullerenes, developed in these last years, has allowed designing the properties of this family of molecules for specific applications in materials science. One of the main tasks to build up solid state devices based on fullerenes is the synthesis of materials doped with a highly dispersed and homogeneous distribution of fullerenes. Many of the peculiar photophysical properties, such as the reverse saturable absorption used to obtain a solid state optical limiter, are in fact lost in the aggregates of fullerenes. Sol-gel processing allows preparing inorganic oxides and hybrid organic-inorganic materials at low temperatures and presents an interesting alternative to organic polymers to entrap molecules of the fullerene family in a solid matrix. Porous inorganic solids and aerogels are also important classes of materials that can be synthesized via sol-gel and can act as hosts of fullerenes. In the present article we have reviewed the main achievements of sol-gel processing of fullerene based nanocomposite materials.     

Sol-Gel Processing of Organic-Inorganic Nanocomposite Protective Coatings

Organic-inorganic nanocomposite protective coatings are prepared on aluminum substrates by the spinning technique with the concept of incorporating homogeneously nanosized particles (of AlOOH, Al2O3, ZrO2, SiC) into molecular organic-inorganic hybrid matrices. The hybrid matrices are prepared from epoxysilane and bisphenol A with imidazol as catalyst. The AlOOH particles are derived from aluminum isoprooxide and introduced into the hybrid sols directly, and Al2O3, ZrO2, SiC particles are first surface-modified with Si–OH from hydrolyzed TEOS. The coatings are dense, smooth and flexible and inhibit corrosion.     

Basic Catalyzed Synthesis of Hybrid Sol-Gel Materials Based on 3-Glycidoxypropyltrimethoxysilane

Hybrid organic-inorganic materials derived from 3-glycidoxypropyltrimethoxysilane have been synthesised using 3-aminoethylaminopropyltriethoxysilane as basic catalyst of epoxy polymerisation and modifier of the structure.Different amounts of aminoethylaminopropyltriethoxysilane have been used to prepare films and bulk samples, from 17 to 48 mol% with respect to the alkoxide content. The materials have been characterised by Fourier Transform Infrared, Raman and multinuclear solid-state Nuclear Magnetic Resonance spectroscopy.Complete opening of epoxy rings in 3-glycidoxypropyltrimethoxysilane has been obtained and the different amounts of catalysts employed directly affected the degree of inorganic cross-linking.     

溶胶-凝胶法制备纳米WO_3气致变色材料

本文主要阐述了纳米WO3气致变色材料的溶胶-凝胶制备方法、气致变色机理及其应用的研究新进展,重点评述了溶胶-凝胶法中各种制备条件诸如掺杂、模板剂、溶剂、热处理温度等对这种材料的结构和性能的影响,最后展望了纳米WO3气致变色材料的研究和应用前景。我们认为,在未来的溶胶-凝胶法制备纳米WO3气致变色材料领域,如何进行最优化的掺杂设计和选择高效模板剂、如何降低气体检测温度以及气致变色机理等将是该项研究的重点。     

In Situ Synthesis Kinetics of Salicylic Acid Terbium Complexes in Sol-Gel Derived Host Materials

In situ synthesis kinetics of salicylic acid terbium complexes in sol-gel derived host materials has been investigated. With the increase of the heat treatment time, the broad excitation band in the excitation spectra of the salicylic acid and terbium chloride co-doped gel glass was formed gradually and the luminescence intensity increased gradually, which indicated the gradual synthesis of the salicylic acid terbium complexes in the gel glass during the heat treatment. In situ synthesis reactions of the salicylic acid terbium complexes in 90°C, 120°C, 150°C were found to be second-order reactions, and can be described by the integrated rate equation: , where x is the fractional concentration of the synthesized complex and t the reaction time. According to Arrhenius equation, the activation energy of in situ synthesis of the salicylic acid terbium complexes in the gel glasses was calculated to be 46.39 KJ/mol.     

溶胶-凝胶法制备有机/无机杂化材料工艺及其应用

介绍了溶胶–凝胶法制备有机/无机杂化材料的原理和基本过程,杂化材料的制备方法及对材料性能的影响,概述了杂化材料在结构材料、光学材料及其它材料中的应用研究。     

Organo‐ and Hydrogelators Based on Luminescent Monocationic Terpyridyl Platinum(II) Complexes with Biphenylacetylide Ligands

A series of phosphorescent terpyridyl platinum(II) complexes with ancillary biphenylacetylide ligands, namely, [(R₃tpy)PtC≡C(biphenyl)]X (R=tBu, H, or Et₂N; tpy=2,2′;6′,2′′‐terpyridyl; X is an anion) were synthesized and structurally characterized by various spectroscopic techniques and X‐ray diffraction methods. Despite a lack of long alkyl chain(s) or hydrogen‐bonding motif(s), complexes [(tpy)PtC≡C(biphenyl)]Cl and [(tBu₃tpy)PtC≡C(biphenyl)]X (X=Cl, ClO₄, PF₆, or BF₄) were found to gelate water and organic solvents, respectively. The self‐aggregation of these complexes in solutions and the resulting gels were investigated with variable‐temperature (VT) ¹H NMR spectroscopy, polarized optical microscopy, and absorption/emission spectroscopy. SEM micrographs on dry gels revealed entangled nanofibers with diameters of 20–40 nm and lengths of tens of micrometers. Powder X‐ray diffraction (PXRD) study revealed various degrees of crystallinity of these fibrillar nanostructures. The substituents on both the terpyridyl and acetylide ligands and counterion of these complexes play a profound but concerted role in tuning the intermolecular metal???metal and/or π–π interactions, and hence the gelation properties.     

NiO-SiO2 Sol-Gel Nanocomposite Films for Optical Gas Sensor

Recently nanocomposites with sensoring function are becoming a new area of interest in the field of optical gas sensor. In fact, the optical transmittance of nano-particles or thin films has been reported to be changed by atmosphere gases. In particular it was found that NiO, Co₃O₄ and Mn₃O₄ thin films showed reversible decrease in the Vis-NIR absorption due to CO.Aim of this work is the synthesis and the characterization of SiO₂ sol-gel glass films doped with NiO nanocrystals.Films of composition (100 – X)SiO₂-XNiO with X = 10, 20, 40, were obtained by mixing a matrix solution of Si(OC₂H₅)₄ (TEOS) and CH₃Si(OC₂H₅)₃ (MTES) as SiO₂ precursors, with a doping solution containing NiCl₂ as precursor for NiO particles.3-Aminopropyltriethoxysilane (3-APTES), bearing either an ammine group capable of coordinating the Ni ions and hydrolysable siloxane groups for anchoring the metal complex moiety to the silicate matrix, was used as bifunctional ligand.Transmission electron microscopy micrographs showed a uniform distribution of round shaped nanoparticles in film heated at 500°C with a mean diameter of 2.5 nm.The film composition evaluated from Rutherford backscattering spectrometry was in good agreement with the nominal one. As expected the density of the films heated at 1000°C is much higher than the density of the film heated at 500°C due to a residual porosity. Fourier transform infrared spectra also confirmed the presence of residual porosity in the films heated at 500°C.     

Strategies for Spatially Separating Molecules in Mesostructured Sol-Gel Silicate Films

Three strategies for placing molecules in designated regions of mesostructured thin films made by the sol-gel dip-coating technique are demonstrated. These strategies all involve one-step syntheses where all of the components are present in the sol from which the substrate is pulled. Silicate films templated by ionic surfactants contain three spatially-separated regions: a silicate framework, an organic region formed by the hydrocarbon tails of the surfactants, and an intervening ionic interface formed by the charged surfactant head groups. The first method exploits lipophilic interactions between the molecule and the micelle to place it in the organic region. The second method uses chemical bonding of multiple trialkoxysilane groups in a three dimensional array on the molecule to place it in the silica framework. The third method uses multiple functionality at opposite sides of the molecule to enable it to span two regions. Luminescent molecules are used, and spectroscopy monitors the formation.     

Photochromic Doped Sol-Gel Materials for Fiber-Optic Devices

Photochromic-doped sol-gel materials have been prepared by adding a spiropyran photochromic dye to a solution of ethoxy silane monomers containing non-reacting ethyl radicals. After polymerization, normal photochromism (i.e., colored material upon UV irradiation) is obtained in the resulting matrix. The sol-gel matrix hinders the organic molecule rotations, thus giving two stable states, which can be reversibly switched by UV and green-blue irradiation respectively.If these materials are attached to optical fibers, the properties of the light throughput may be modified. Simple fiber-optic/photochromic devices made of two optical fibers placed in a V-groove removable connector have been prepared. Once cured, these devices behave as optically addressed variable delay generators. The same devices can be used for preparing simple optical switches and routing systems.     

Hybrid Organic-Inorganic Sol-Gel Materials Based on Epoxy-Amine Systems

Understanding the synthesis-structure-properties relationship of hybrid organic-inorganic materials is an important and fundamental task to develop a new generation of highly performing systems for the new needs of nanotechnologies. This issue is, also, important to improve the properties of hybrids when used in applications where nanoscale control is not a fundamental request. In this article, a short overview of epoxy amine sol-gel hybrids is reported. The synthesis of these materials has a large flexibility to allow the fabrication of a wide group of hybrids with different structures and properties, whose applications are ranging from non-linear optics to adhesive and protective coatings.     

Photochromism of Peroxotungstic Acid/PVP Nanocomposite Obtained by Sol-Gel Method

Peroxotungstic acid (PTA)/PVP composite film was prepared via sol-gel method. TEM revealed that the composite films consist of peroxotungstic acid nano-grains embedded in amorphous PVP matrix. The samples were observed to exhibit reversible photochromic effect when irradiated with solar light. The iodometric titration and FT-IR spectra indicated the presence of peroxo groups (W–O–O–W) incorporated into PTA structure. EPR measurement revealed the presence of unpaired paramagnetic electrons in PTA/PVP nanocomposite gel. The UV-Vis-Nir transmittance spectra and EPR spectroscopy of sample indicate that the photochromic behaviour is due to the photo-excitation of the unpaired electrons at W–O octahedral sites of peroxotungstic acid.     

Study on the Photoluminescence Properties of Sol-Gel Ti3+ Doped Silica Glasses

Sol-gel derived Ti³⁺ doped SiO₂ glasses have been prepared by heat-treatment in reducing condition. A broad emission band covering entire visible-light range, with two maxiam at 460 and 560 nm, was observed in the doped reduced glasses. The emission peak at 460 nm is attributed to the defects in the sol-gel SiO₂ glass network, and the one at 560 nm is assigned to the transition ²A_1g ²B_2g of Ti³⁺ in the reduced glasses.     

有机/无机纳米复合材料的研究进展

有机／无机纳米复合材料以其优异的性能越来越受到人们的关注。本文分析总结了有机／无机纳米复合材料的制备方法、性能及其应用,着重介绍了溶胶一凝胶法和原位聚合法。参考文献28篇。