溶胶法制备的二氧化硅与二氧化钛复合薄膜的性能

在室温下, 采用溶胶法在玻璃基板上制备了厚度约为100 nm的均匀、透明的纳米SiO2-TiO2复合薄膜.研究了不同温度处理后薄膜的超亲水性、光催化能力等光致活性.通过XPS对薄膜表面及近表面元素的化学态的研究发现, Ti在表面及近表面不仅以Ti4＋形式存在, 也存在少量Ti3＋.紫外光照射后, 部分Ti4＋ 转变成了Ti3＋. XRD研究表明, 该薄膜中的TiO2主要以锐钛矿形式存在, 而且其晶粒大小为14～20 nm.用AFM研究了SiO2-TiO2薄膜的表面形貌及不同的温度处理对TiO2颗粒大小的影响.     

Crystallization Behavior of SiO2-TiO2 Sol-Gel Thin Films

The aim of this work was to investigate the crystallization behavior of thin films of SiO₂−TiO₂ made by the sol-gel process as function of the TiO₂ content and the temperature and time of heat treatment. Precursor solutions were prepared by hydrolysis of TEOS (tetraethoxysilane) and TPOT (titaniums tetraisopropoxide). Multilayer films were spun on single crystal silicon wafers. The compositions studied were (on a molar percentage basis) 20TiO₂−80SiO₂, 30TiO₂−70SiO₂, 40TiO₂−60SiO₂ and pure TiO₂. The films were heat treated at different temperatures between 300°C and 1200°C, for different periods of time (30 s-90 h). The crystallization kinetics were followed by micro-Raman spectrometry. Grazing incidence X-ray diffraction showed that the films crystallized into one or both of two crystalline phase of TiO₂: anatase and rutile (for pure TiO₂ only). The volume fractions of the crystalline phase varied from very low values (<1%), up to 100%, for a TiO₂ sample heat treated at 800°C for 8 hours. The results show that the volume fraction of crystalline phase is strongly influenced by the heat treatment temperature and also, to a smaller extent, by the heat treatment time. The most important parameter, however, is the composition of the films: the higher their TiO₂ concentration, the lower is the crystallization temperature and the larger is the crystallized fraction.     

溶胶—凝胶法制备NiO／SiO2催化剂研究

分别以正硅酸乙酯、硝酸镍为硅源和镍源,采用溶胶－凝胶法,经超临界流体干燥和普通干燥制备了NiO-A-SiO2、NiO-G-SiO2催化剂;以气凝胶和干凝胶为载体,采用浸渍法制备了NiO/A-SiO2、NiO/G-SiO2催化剂。并用XRD、TEM、BET、TPR等手段,研究了制备方法对催化剂织构、结构和Ni物种存在形态的影响,发现NiO-A-SiO2和NiO-G-SiO2催化剂上高度分散的NiO簇团与SiO2之间有较强的相互作用,其顺酐液相选择加氢转化率低于10％;NiO/G-SiO2催化剂上,以单一物种形态存在的NiO与SiO2相互作用弱,顺酐转化率为42％;NiO/A-SiO2催化剂上,以多种形态存在的微量NiO与SiO2间的相互作用较复杂,其顺酐液相选择加氢的转化率和丁二酸酐的选择性分别可达100％和98％。     

Size Effect on Crystal Structures of Barium Titanate Nanoparticles Prepared by a Sol-Gel Method

Barium titanate nanoparticles were synthesized by the hydrolysis of complex alkoxide precursor that was prepared in a reflux of metallic barium and tetraethylorthotitanate in solvent. The hydrolysis was performed by the addition of water/ethanol solution to the precursor solution. As reflux time increased, particle sizes, which were measured with transmittance electromicroscopy, became smaller followed by sharpening of size distribution. As water concentration and benzene content in the hydrolysis increased, the particle size increased with crystallite size that was determined with X-ray diffractometry. No significant difference was observed between the particle and crystallite sizes up to 30 nm. Over the size of 30 nm, the particle size was larger than the crystallite size because of generation of polycrystallites. Annealing treatments in air at 400 and 1000°C also increased both the particle and crystallite sizes. The crystallite sizes estimated from the (111) peaks were smaller than those from (110) peaks in a range of sizes larger than 40 nm, which indicated that the critical crystallite size of transformation from cubic to tetragonal structures was approximately 40 nm.     

Influence of Solvent Concentration on the Microstructure of SiO2-TiO2 Sol-Gel Films

Spin-coating is one of the possible methodsfor the fabrication of optical planar waveguides. These have several applications in integrated optical devices, provided that their optical losses are below ≈1 dB/cm. The attenuation is caused in part by surface and bulk scattering. The latter depends on the microstructure of the films and, more particularly, the porosity, which is studied here. A series of SiO₂−TiO₂ films were prepared from solutions containing different concentrations of ethanol. The influence of the ethanol/(Si+Ti)_alkoxides volume ratio on the porosity was investigated by Ellipsometry, Infrared Spectroscopy, and Scanning Electron Microscopy. The porosity volume fraction was found to reach a minimum when the ethanol volume ratio is near 4.     

Crystallization Behavior of SiO2-TiO2 Ceramics Derived from Titanosiloxanes on Pyrolysis

The crystallization behavior of SiO2-TiO2 ceramics derived from titanosiloxanes was investigated in relation to the structure of the precursor and the pyrolysis temperature. The titanosiloxanes, [Si(OBut)2OTi(acac) 2O]2, [(ButO)3SiO] 2Ti (OPri)2, and [(ButO)3SiO] 3Ti(OPri), were pyrolyzed in an air atmosphere to form SiO2-TiO2 ceramics which crystallized to anatase at 600–650°C, 700–750°C, and 800–850°C, respectively. The crystallization temperature decreased with increased titanium content of the precursor. The average crystallite size of anatase increased with increased pyrolysis temperature and the titanium content. The crystallization temperature and the crystallite size for SiO2-TiO2 ceramics is controlled by the precursor structure, which may enable control of the physical properties of the ceramic materials.     

Atomic Force Microscopic Studies of Porous TiO2 Thin Films Prepared by the Sol-Gel Method

Porous titanium dioxide thin films were prepared from alkoxide solutions with and without polyethylene glycol (PEG) by the sol-gel method on soda-lime glass. The effects of PEG addition to the precursor solution on the microstructure and roughness of the resultant thin films were investigated by atomic force microscopy (AFM). It was found that TiO₂ films prepared from the precursor solution without PEG had granular microstructure and flat texture, and was composed of about 100 nm spherical particles. With an increase in the times of coating cycles, the roughness of films decreased and the size of TiO₂ particles increased. On the other hand, the larger the amount and molecular weight of the added PEG in precursor solutions, the larger the diameter and the depth of pores in the resultant films on the decomposition of PEG during heat-treatment. The surface of the films was also rougher, and fewer pores were produced during heat-treatment. The mechanism of porous structure formation in the TiO₂ films was explained using the principle of spinodal phase separation.     

Analysis of Antimony Doping in Tin Oxide Thin Films Obtained by the Sol-Gel Method

The antimony doping in SnO₂ thin films prepared by the sol-gel dip-coating method has been studied using two characterization techniques. In order to determine the actual doping level directly in the deposited layers, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been used. We found that this doping level is systematically lower than expected from the starting solutions composition, and that two oxidation states are present: Sb³⁺ and Sb⁵⁺. As the antimony content increases, there is a competition between Sb⁵⁺ and Sb³⁺ species.The SnO₂: Sb thin films have also been observed by transmission electron microscopy (TEM), showing that the measured mean size of crystallites decreases as the Sb content increases in the oxide. No precipitates of either Sn or Sb oxides (other than SnO₂) could be detected.     

Formation of Superhydrophobic-Superhydrophilic Pattern on Flowerlike Alumina Thin Film by the Sol-Gel Method

We have prepared superhydrophobic surfaces which become superhydrophilic by heat-treatment at 500°C or irradiation of UV-light. When hydrolyzed fluoroalkyltrimethoxysilane (FAS) was coated on Al₂O₃ gel film with a roughness of 20 to 50 nm, the films showed superhydrophobicity and high transparency; the contact angle for water of the film was 165° and the transmittance for the visible light was higher than 92%. When the FAS-coated thin films were heat-treated at temperatures higher than 500°C, the films became superhydrophilic; the contact angle for water on the films was smaller than 5°. Thin films of amorphous TiO₂ or anatase TiO₂ were coated between Al₂O₃ gel and FAS layer, and the contact angle for water was also about 160°. UV irradiation using high-pressure mercury lamp on these films resulted in the contact angle to be smaller than 5°. When UV light was irradiated through a photomask, superhydrophobic-superhydrophilic micropatterns applicable as a stamper for printing or a substrate of micro-optical components were successfully obtained on the films.     

Crystallization Behavior and Properties of B-Doped ZnO Thin Films Prepared by Sol-Gel Method with Di erent Pyrolysis Temperatures

Boron-doped zinc oxide transparent (BZO) films were prepared by sol-gel method. The effect of pyrolysis temperature on the crystallization behavior and properties was systematically investigated. XRD patterns revealed that the BZO films had wurtzite structure with a preferential growth orientation along the c-axis. With the increase of pyrolysis temperature, the particle size and surface roughness of the BZO films increased, suggesting that pyrolysis temperature is the critical factor for determining the crystallization behavior of the BZO films. Moreover, the carrier concentration and the carrier mobility increased with increasing the pyrolysis temperature, and the mean transmittance for every film is over 90% in the visible range.     

沉积温度对Cu_2O薄膜生长过程及光电性能的影响(英文)

以硫酸铜为铜源,采用一步化学浴沉积法制备出了晶粒尺寸可调的纳米晶Cu2O薄膜。通过X射线衍射、扫描电镜和紫外可见分光光度法研究了沉积温度对薄膜晶体结构、成核密度、晶粒尺寸、薄膜厚度和光电性能的影响。结果表明,当在60~90℃范围内调节温度时,能够很好地控制晶粒尺寸、薄膜厚度,并将禁带宽度控制在33~51 nm、392~556 nm和2.47~2.61 eV范围内;随着晶粒尺寸的减小,紫外可见光谱的吸收边有明显的蓝移。此外还对薄膜的生长过程,成核密度和颗粒尺寸变化的机理进行了讨论。     

沉积温度对Cu2O薄膜生长过程及光电性能的影响

以硫酸铜为铜源,采用一步化学浴沉积法制备出了晶粒尺寸可调的纳米晶Cu₂O薄膜。通过X射线衍射、扫描电镜和紫外可见分光光度法研究了沉积温度对薄膜晶体结构、成核密度、晶粒尺寸、薄膜厚度和光电性能的影响。结果表明,当在60~90℃范围内调节温度时,能够很好地控制晶粒尺寸、薄膜厚度,并将禁带宽度控制在33~51nm、392~556nm和2.47~2.61eV范围内;随着晶粒尺寸的减小,紫外可见光谱的吸收边有明显的蓝移。此外还对薄膜的生长过程,成核密度和颗粒尺寸变化的机理进行了讨论。     

Preparation and Characterization of TiO2 Thin Films by Sol-Gel Method

Titanium dioxide (TiO₂) thin films have been deposited on silicon and glass substrates by the sol-gel process using titanium iso-propoxide [Ti(O-i-C₃H₇)₄]. The bond configuration of the TiO₂ thin films was analyzed by using FTIR in the wavenumber range from 400 to 4000 cm^–1. The spectral transmittance of as-deposited TiO₂ films deposited on fused silica glass was measured in the wavelength range from 200 to 900 nm. X-ray diffraction measurements were performed to determine the crystallinity of the TiO₂ films. As-deposited films were amorphous. As the film was annealed at higher temperature, the structure was transformed from amorphous to the anatase crystalline state. The chemical composition of the deposited film was investigated using X-ray photoelectron spectroscopy (XPS). The films are essentially stoichiometric with carbon as the dominant impurity on the surface. Raman spectra show the characteristic of TiO₂ anatase phase. The electrical properties of the TiO₂ films were measured using capacitance-voltage (C-V) and current-voltage techniques. From C-V measurements, the dielectric constants were calculated to be approximately 26 for the as-deposited films and 75–82 for films annealed at 700°C in different atmosphere. For the as-deposited samples, the breakdown voltage was 2.7 MV/cm, and for an electric field of 1 MV/cm, the leakage current was 5 × 10^–5 A/cm² and the resistivity was 2.2 × 10¹⁰ -cm.     

一种室温下制备乙酰丙酮铜络合物的方法

室温下以乙酰丙酮和自制的碱式碳酸铜为原料合成乙酰丙酮铜。最佳合成条件是碱式碳酸铜和乙酰丙酮的物质的量比为1:4,反应时间2 h,产率可达99%,该化合物经过红外光谱和元素分析等表征。该反应具有操作和后处理方便、产品纯度和产率高等优点,同时将学生实验得到的产品进行有效利用。     

溶胶-凝胶法制备的Y_2O_3薄膜的光波导性质研究

用醋酸钇溶解于甲氧基乙醇的溶胶 凝胶法制备了Y2 O3光波导薄膜。通过二乙烯三胺的络合作用 ,获得了均匀和稳定的前驱液 ,并用浸渍提拉法得到了薄膜。差热分析、红外吸收光谱被用来表征Y2 O3凝胶和粉末。用XRD、扫描电子显微镜、m线法和波导荧光光谱法研究了Y2 O3光波导薄膜的结构和光波导性质。结果表明 ,Y2 O3薄膜对于光活性掺杂是一种很好的基质材料 ,预示Y2 O3薄膜在光电子方面具有巨大的应用前景。     

Synthesis of Bi2O3 and Bi4(SiO4)3 Thin Films by the Sol-Gel Method

Bi2O3 thin films were prepared by dipping silica slides in ethanolic solutions of tris(2,2-6,6-tetramethylheptane-3, 5-dionato)bismuth(III) [Bi(dpm)3] [1] and heating in air at temperatures 500°C. Bi4(SiO4)3 homogeneous thin films were obtained from the reaction of the bismuth oxide coating with the silica glass substrate at temperatures higher than 700°C. For heat treatments at temperatures between 600°C and 700°C, Bi2SiO5 coatings were obtained. The composition and microstructure evolution of the films were determined by Secondary Ion-Mass Spectrometry (SIMS), X-Ray Photoelectron Spectroscopy (XPS) and Glancing Angle X-Ray Diffraction (GA-XRD). The synthesis procedure was reproducible and allowed the control of the Bi2O3 phase composition. Moreover, the thin film annealing parameters were correlated with the formation of bismuth silicates, among which Bi4(SiO4)3 (BSO) is very appealing for the production of fast light-output scintillators [2].     

反相胶束增稳室温荧光法测定中药痕量有效成分氯原酸的研究

研究了双－「２－乙基己基」－磺酸基琥珀酸（气溶胶ＯＴ或ＡＯＴ）／环己烷／水反相胶束介质吕草药有效成分氯原酸的荧光性质,发现氯原酸在上述反相胶束体系中,不仅荧光有增强现象,而且分子激发和发射光谱发生红移。首次建立了反相胶束增稳室温荧光法测定氯原酸的新方法。该法测定的线性范围为：６×１０＾－７－－４×１０＾－６（ｇ／ｍＬ）,检出限为：１．２×１０＾－７ｇ／ｍＬ）,相地标准偏差为：１．３（％）。     

Third-Order Nonlinear Optical Properties and Dielectric Properties of Pb-Complex Perovskite Thin Films Prepared by Sol-Gel Method

The third-order nonlinear optical properties of the sol-gel derived Pb(Fe_1/2Nb_1/2)O₃-PbTiO₃ (PFN-PT) thin films have been investigated by the THG method. The χ⁽³⁾ values of PFN-PT thin films increased from 3.2×10⁻¹² esu (PT) to 8.5×10⁻¹² esu (PFN) with increasing content of Fe³⁺ ions which possessed very high second-hyperpolarizability, ψ(Fe_2/3O). It was experimentally confirmed that complex oxides such as ABO₃-type perovskites consisting of large non-transition metal A-site cations and small transition metal B-site cations exhibited high χ⁽³⁾ as expected from Lines' model. It was also found that the χ⁽³⁾ values of complex oxides could be estimated from the second-hyperpolarizabilities of the constituent single oxides reported so far. Because of the large remanent polarization, PT thin films may exhibit the highest χ⁽³⁾ among the ferroelectric PFN-PT thin films studied in the present work. The maximum dielectric constant, ε, of 1990 at room temperature was obtained for 0.5PFN·0.5PT thin films, whose composition corresponds to so-called morphotropic phase boundary (MPB).     

Thin and Thick RuO2-TiO2 Coatings on Titanium Substrates by the Sol-Gel Process

Thin and thick 20 mol% RuO₂–80 mol% TiO₂ coatings have been obtained through a combination of different preparation parameters, including catalyst and oxide concentrations, using ruthenium trichloride trihydrate and titanium n-butoxide. Acid catalysed solutions produced uniform, crack-free coatings that were too thin for use on electrocatalysis electrodes. On the other hand, base catalysed solutions produced thicker, cracked coatings. Electrodes prepared with base catalysed solutions performed well in electrocatalysis lifetime testing for corrosion stability.     

隐丹参酮和丹参酮IIA滤纸基质室温磷光法的研究

考察了隐丹参酮和丹参酮 IIA的滤纸基质室温磷光法 ( PS- RTP)特性。选择Cd( Ac) 2 作为重原子微扰剂 ,对影响这两种丹参酮类化合物发光强度的各种因素进行了详细研究。同时建立了隐丹参酮和丹参酮 IIA的 PS- RTP分析测定的新方法