纳米Cu/Al_2O_3组装体模板合成与光吸收

以有序的多孔氧化铝为模板,利用交流电在孔洞中沉积金属铜得到纳米Cu粒子/Al2O3组装体系.透射电镜观察显示随着交流电沉积时间的延长,孔洞中纳米Cu粒子数量增加.测量了纳米Cu粒子/Al2O3组装体系的紫外可见光吸收光谱,发现随着孔洞中纳米Cu粒子数量增加,纳米Cu粒子/Al2O3组装体系的吸收带边大幅度红移;根据雷利散射引起的消光增强解释了组装体吸收带边红移的原因.同时发现Cu粒子的表面等离子共振吸收峰消失及组装体在吸收带边区光吸收值满足间接带隙半导体光吸收边的表达式.     

透明导电ZnO薄膜的电化学制备及性能研究

以修饰的ITO玻璃为衬底,以不同浓度Zn(NO3)2.6H2O作为电解质溶液,采用阴极恒流沉积法制备了不同纳米结构的ZnO薄膜。用X射线衍射(XRD)、场发射扫描电镜(FE-SEM)、四探针仪(RTS-8)、紫外-可见(UV-Vis)光谱仪、循环伏安等分别表征薄膜的晶相、形貌和厚度、方块电阻、紫外-可见光透过率和氧化还原电位。结果表明:低浓度溶液沉积得到的c轴取向1D ZnO纳米柱和高浓度溶液沉积得到的致密2D六方ZnO纳米片在可见光范围(400～900 nm)的透过率均可高达85%以上,方块电阻约为14.5Ω/□。两种结构的氧化还原电位有显著区别,纳米柱的为-0.54 V(vs.SCE),而纳米片的为-0.72 V(vs.SCE),说明纳米片状的ZnO薄膜具有更为良好的化学稳定性。     

纳米Cu/Al2O3组装体模板合成与光吸收

以有序的多孔氧化铝为模板,利用交流电在孔洞中沉积金属铜得到纳米Cu粒子/Al₂O₃组装体系.透射电镜观察显示随着交流电沉积时间的延长,孔洞中纳米Cu粒子数量增加.测量了纳米Cu粒子/Al₂O₃组装体系的紫外可见光吸收光谱,发现随着孔洞中纳米Cu粒子数量增加,纳米Cu粒子/Al₂O₃组装体系的吸收带边大幅度红移;根据雷利散射引起的消光增强解释了组装体吸收带边红移的原因.同时发现 关键词： 纳米Cu 模板合成 光吸收     

乙二醇对反向微乳辐照法制备纳米级氧化亚铜形貌的影响

在乙二醇存在下,采用反向微乳辐照法制备了纳米级氧化亚铜(Cu2O)立方体.利用吸收光谱、X射线粉末衍射(XRD)、透射电镜(TEM)、高分辨透射电镜(HRTEM)、扫描电镜(SEM)等对所得产物进行了表征.吸收光谱显示随着乙二醇用量逐渐增加,Cu2O的半导体激子吸收特征峰逐渐增强并且红移,初步表明所得产物的粒径逐渐增大.常规透射电镜的结果表明所得Cu2O的纳米颗粒的粒径逐渐增大,并且变得规整.实验结果表明,乙二醇对Cu2O纳米粒子的形貌具有重要影响.乙二醇的存在增大了微乳水池粘度,而粘度大小影响水化电子的反应性,从而影响Cu2O的生成速率、结晶过程.它还可以降低微乳界面刚性,增大水池间的物质交换而影响Cu2O的成核和结晶;此外,它对Cu2O特定晶面的吸附影响其最终形貌.     

离子交换树脂法制备纳米ZnS

以Zn(NO3)2·6H2O为锌源,Na2S为硫源,采用强碱性阴离子交换树脂法制备了纳米ZnS,并对形成的ZnS纳米粒子进行了XRD、TEM表征.XRD表征计算结果表明样品约为粒径6-10nm的小颗粒,TEM表征结果可观察到样品为由6-10nm的小颗粒团聚而成的50-80nm的大颗粒组成的.     

微波辅助表面修饰：大范围可控调节CdTe纳米粒子发光光谱

利用微波辅助合成方法简单快捷地调节水溶液中CdTe纳米晶的发光性质，使其发光光谱可以覆盖整个可见光区，甚至部分扩展到近红外(537～680 nm)．这种光谱调控的原因可能是由于CdTe纳米晶表面形成了核壳结构以及纳米粒子之间形成复杂的纳米组合体．     

Bi12TiO20纳米粉体的制备及其光吸收特性研究

以钛酸四丁酯和硝酸铋为原料 ,利用化学溶液分解法制备了Bi12 TiO2 0 纳米多晶粉体 .采用XRD和TEM对其结构和形貌进行了表征 .结合热重 差热 (TG DTA)分析 ,探讨了Bi12 TiO2 0 晶相的形成机理 .通过UV Vis漫反射谱的测定 ,研究了Bi12 TiO2 0 纳米晶粉体的光吸收特性 .结果显示 ,从组成为化学计量比的前驱液中可以很容易制得纯Bi12 TiO2 0 纳米晶粉体 ,该Bi12 TiO2 0 纳米晶粉体呈现了在很宽的波长范围内 (5 6 0～ 385nm )对光的吸收的特性 .     

用光声技术研究半导体TiO2,ZnO纳米晶粉的光学特性

应用新型的光声光谱技术,研究了不同种类和不同制备工艺条件的半导体纳米晶粉的光学特性,测量了半导体TiO2、ZnO和掺铝ZnO纳米晶粉的光声光谱,获得了这些半导体纳米晶粉的带隙和光谱吸收系数.研究结果表明,相同种类和相同颗粒形状的半导体纳米晶粉的粒径越小,光学吸收系数越大.半导体纳米晶粉的带隙与相同种类纳米颗粒形状(圆球...     

L-B技术进展——一种半导体纳米粒子的组装技术

纳米粒子由于有量子尺寸效应,因此它的物理、化学特性既有别于单个分子、几个分子组成的多聚体,又有别于体相材料。在溶液中利用制备胶体的方法来制备半导体纳米粒子已经比较成熟。稳定溶液中纳米粒子的方法进展甚速,如离子修饰、胶束固定等,而且它们在能量     

纳米硫化锌的制备及光谱分析

采用超重力反应结晶法制备了纳米硫化锌粒子,并通过透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、X射线光电子能谱仪(XPS)、傅里叶红外光谱仪(FTIR)、紫外-可见光分光光度计(UV-Vis)和X射线能谱仪(EDX)对纳米硫化锌的形貌、结构、组成和光谱性能进行了细致分析。结果表明：超重力反应结晶法制备的纳米硫化锌粒子为球形,平均粒径为42 nm;XRD图谱表明纳米硫化锌呈现较好的闪锌矿晶型; XPS能谱表明纳米硫化锌的S(2p)的电子结合能为162.6 eV,Zn的2p_3/2,2p_1/2的电子结合能分别为1021.4, 1044.6eV。红外光谱研究表明纳米硫化锌在400～4 000cm-1范围内具有良好的红外透过率。紫外-可见光谱研究发现纳米硫化锌在200～340nm的紫外区域有较强的吸收,其禁带宽度为3.57eV。EDX能谱表明该法制备的纳米硫化锌具有较高的纯度。     

Formation and characterization of conductive thin layers of copper sulfide (CuxS) on the surface of polyethylene and polyamide by the use of higher polythionic acids

Layers of copper sulfide of varying composition and properties are formed on the surface of polyethylene and polyamide by a sorption-diffusion method using solutions of higher polythionic acids, H₂S_nO₆. The concentration of sulfur adsorbed-diffused into PE and PA depends on the degree of the acid sulfurity, n, the temperature of the solution and the period of the polymer treatment. The amount of copper in a sulfide (Cu_xS) layer formed after the sulfured polymer treatment with a solution of Cu(I-II) salt is strongly dependent on the concentration of sulfur in the PE and PA. By the chemical analysis of the obtained sulfide layers was determined that a value of x in the Cu_xS layers varies in the interval 1 < x < 2. The microscopic investigation of transverse sections of PE and PA samples with copper sulfide layers showed that the major part of copper sulfide is in the surface matrix of the polymer. X-ray diffraction studies of the Cu_xS layers obtained seven phases: with x = 2 (chalcocite), 1.9375 (djurleite), 1.8 (digenite), 1.75 (anilite), 1.12 (yarrowite), 1.06 (talnakhite) and 1 (covellite). The measurements of the electrical conductance of Cu_xS layers (0.1-4 S cm⁻²) showed that its value greatly depends on the conditions of PE and PA interaction with H₂S_nO₆ and of further interaction with Cu(I-II) salt solution, on the chemical and phase composition of the layer.     

An XPS,ISS and ESR Comparative Study of Eight-Coordination of Copper (II) Ions in the CuTho Compounds

In this study, we attempted to clarify the coordination state and the distribution of copper (II) ions in the CuThO compounds prepared by coprecipitation, by using several physico-chemical techniques in particular, X-Ray Photoelectron Spectroscopy (XPS).

For atomic ratios Cu/Th ≤ 0.25, the copper (II) species are mainly located near the thoria surface. The Cu2p_3/2 level shows a chemical shift towards the lower binding energy compared to Cu²⁺ ions in CuO and also a net decrease in the intensity of the satellite peak, characteristic of copper (11). A relation between these observations and the covalent character o f Cuzt- 02- bond i s esta- blished. Eightfold coordination of copper (11) i n the thoria lattice i s evident. These conclusions are in good agreement with Electron Spin Resonance (ESR) results.

For a higher atomic ratio (Cu/Th > 0.25), a formation o f copper oxide crystallites i s observed on the thoria surface.     

Photoluminescence of Cu:ZnS, Ag:ZnS, and Au:ZnS nanoparticles applied in Bio-LED

In this work, transition elements, including Cu²⁺, Ag⁺, and Au³⁺, were used to dope in zinc sulfide (ZnS) by chemical solution synthesis to prepare Cu:ZnS, Ag:ZnS, and Au:ZnS nanoparticles, respectively. Transition elements doping ZnS nanoparticles form the electronic energy level between the conduction band and valance band, which will result in the green light emission. There is a zinc sulfide emission shift from blue (~3.01 eV) to green light (~2.15 eV). We also found that Au:ZnS nanoparticles will emit a green light (~2.3 eV) and a blue light (~2.92 eV) at the same time because the mechanism of blue light emission was not broken after Au element had been doped. Furthermore, we used sodium chlorophyllin copper salt to simulate chlorophyll in biological light emission devices (Bio-LED). We combined copper chlorophyll with Cu:ZnS, Ag:ZnS, and Au:ZnS nanoparticles by a self-assembly method. Then, we measured its photoluminescence spectroscopy and X-ray photoelectron spectroscopy to study its emission spectrum and bonding mode. We found that Au:ZnS nanoparticles are able to emit green and blue light to excite the red light emission of copper chlorophyll, which is a potential application of Bio-LED.     

Copper diffusion in copper sulfide: a systematic study

Copper sulfide Cu_2−xS is a model mineral for chalcogenides because of the existence of a non-stoichiometric compounds series in the range Cu₂S - CuS in which properties change with x. For this reason, we have studied the influence of the mineral composition on the diffusion in this solid. Electrochemical Impedance Spectroscopy (EIS) applied to Cu_2-xS/cupric sulfate electrolyte was the main investigation technique. It enabled us to work at the equilibrium potential at which the composition is fixed and known. Changing the composition by electrochemically removing (or adding) a known amount of Cu, we were able to determine the chemical diffusion coefficient of copper in the composition range (from x=0 to 0.066). In this work, we present the results obtained in the chalcocite and djurleite phases. These results were compared to other values reported in the literature. From this systematic study we discuss various diffusion mechanisms. Our observations support that in chalcocite and djurleite Cu diffuses via a vacancy mechanism. Paper presented at the 5th Euroconference on Solid State Ionics, Benalmádena, Spain, Sept. 13–20, 1998.     

Polymeric sulfides CdS,CuS, and NiS in polyvinyl alcohol matrix

Cadmium, copper, and nickel sulfides have been synthesized in a polyvinyl alcohol matrix. The specimens have been investigated by means of vibration spectroscopy and X-ray diffraction analysis. The obtained data have confirmed the formation of cadmium sulfide with a polymeric chain structure in polyvinyl alcohol. The possibility of producing similar materials based on copper and nickel sulfides has been discussed.     

XRF和LA-ICPMS测定硫化物熔片中的主次量元素

采用高纯HNO₃为氧化剂代替传统的氧化剂,以GeO₂为玻璃化试剂,建立了一种简单、高效的硫化物熔融玻璃片的前处理方法。XRF和LA-ICPMS分析结果表明,相对于粉末压片法,熔片法制备的样品具有更好的均一性和可靠性。3种硫化物国家一级标准物质的XRF和LA-ICPMS主次量元素(Si,Al,Fe,Mg,K,Ca,Na,Mn,Cu,Zn)分析测试结果均与推荐值相吻合(Ti缺少推荐值),测定误差都在允许范围内,XRF三次熔片测试结果的精密度RSD<5.6%;LA-ICPMS 15次测试结果精密度RSD<3%。表明建立的硫化物熔融玻璃片的前处理方法可较好的应用于XRF和LA-ICPMS分析硫化物中的主次量元素。     

Sulfur and oxygen isotope geochemistry of acid mine drainage--the polymetallic sulfide deposit "himmelfahrt fundgrube" in Freiberg (Germany)

We investigated physical, chemical and isotope (S, O) parameters of sulfate from acid mine drainage from the polymetallic sulfide ore deposit Freiberg (Gennany), which was mined for more than eight hundred years. Two main groups of water were distinguished: 1. Flowing mine water with sulfate concentrations of less than 9,000 mg/l and pH values higher than 3.2, 2. Pore water in weathered low grade ores and pools with sulfate concentrations higher than 9000mg/l and pH values below 3.2. The sulfur and oxygen isotope composition of sulfate from flowing mine waters reflects mixing of sulfate from two sulfur sources: a) atmospheric sulfur from precipitation and b) sulfate formed as a result of sulfide oxidation processes. Sulfur isotope values of mine water sulfate were used to estimate the contribution of sulfate derived through oxidation of sulfides. The sulfur isotope composition of pore water sulfate and precipitated sulfate (jarosite) from weathered low grade ore samples is identical to the sulfur isotope composition of primary sulfides. The oxygen isotope composition of pore water sulfate from low grade ore samples indicates that the oxidation process proceeds relatively slowly in 02-depleted waters, probably without significant microbial catalysis.     

退火和淬火对电致发光材料老化的影响

退火和淬火对交流粉末电致发光老化的改善是最有效的方法,原因尚未清楚。本文通过发射光谱、热释光和离子探针实验首次提出:在退火和淬火速冷过程中铜的分布发生了变化,由于铜的析出,聚集在晶体表面缺陷上,形成了高场所必需的硫化锌—硫化铜结,增加了晶体中场分布的不均匀性和势垒高度,稳定了硫化铜相,改善了场的分布和初电子注入条件,因而,改善了电致发光老化。     

Sulfur and Oxygen Isotope Geochemistry of Acid Mine Drainage—The Polymetallic Sulfide Deposit “Himmelfahrt Fundgrube” in Freiberg (Germany)

Abstract

We investigated physical, chemical and isotope (S, O) parameters of sulfate from acid mine drainage from the polymetallic sulfide ore deposit Freiberg (Germany), which was mined for more than eight hundred years. Two main groups of water were distinguished:

1. Flowing mine water with sulfate concentrations of less than 9000 mg/1 and pH values higher than 3.2

2. Pore water in weathered low grade ores and pools with sulfate concentrations higher than 9000 mg/1 and pH values below 3.2.

The sulfur and oxygen isotope composition of sulfate from flowing mine waters reflects mixing of sulfate from two sulfur sources: a) atmospheric sulfur from precipitation and b) sulfate formed as a result of sulfide oxidation processes. Sulfur isotope values of mine water sulfate were used to estimate the contribution of sulfate derived through oxidation of sulfides. The sulfur isotope composition of pore water sulfate and precipitated sulfate (jarosite) from weathered low grade ore samples is identical to the sulfur isotope composition of primary sulfides. The oxygen isotope composition of pore water sulfate from low grade ore samples indicates that the oxidation process proceeds relatively slowly in O₂-depleted waters, probably without significant microbial catalysis.