聚合物为模板制备CdS, ZnS及其掺杂纳米材料

以聚苯乙烯-马来酸酐为模板,合成了CdS,CdS︰Mn,ZnS,ZnS︰Mn及ZnS︰Tb纳米微粒.紫外吸收光谱表明所得微粒尺寸均匀,TEM结果显示CdS纳米微粒的尺寸为2.5 nm.从荧光光谱观察到掺杂离子的特征发射峰,证实了基质到掺杂离子的能量传递.通过红外光谱研究了聚合物与金属离子的键合作用,金属离子首先与聚合物的羧基配位,生成硫化物纳米微粒后,聚合物又包覆在纳米微粒的表面形成保护层.     

聚乙烯烷酮修饰CdS纳米微粒的制备及其光电转移特性

以聚乙烯烷酮（PVP）为修饰剂,制备了CdS纳米微粒。实验结果表明PVP与CdS纳米微粒间存在着强的相互作用,PVP和CdS纳米微粒的荧光都在很大程度上发生淬灭。其原因在于作为修饰剂的PVP与CdS纳米微粒子间发生了特殊缔合．受激时形成共振激发态,电子能量弛豫被延迟。     

巯萘剂表面修饰的CdS纳米微粒的合成及发光特性

用疏萘剂(TN)作为表面修饰剂,在甲醇溶液中合成了CdS/TN纳米微粒,用TEM测得纳米微粒呈球形,其粒径约10nm,吸收光谱和荧光光谱研究表明,[S^2-]/[TN]浓度比、TN和镉离子的浓度对CdS/TN纳米微粒的粒径及发光特性具有显著影响,且随着条件的改变,CdS/TN纳米微粒的发射波长红移100nm,表现出明显的量子尺寸特性.XPS显示所制得表面修饰纳米微粒的核为CdS.     

水热法合成CdS/ZnO核壳结构纳米微粒

以半胱氨酸镉配合物为前驱体,采用水热法合成CdS纳米微粒,并以ZnO对其进行表面修饰,形成具有核／壳结构的CdS／ZnO半导体纳米微粒,CdS纳米微粒表面经ZnO修饰后,其带边发射大大增强,透射电镜显示,110℃下反应4h所得的CdS／ZnO颗粒尺寸约为20nm,电子衍射表明其结构为六方相。     

聚苯胺对纳米CdS的光致发光增强效应

利用电化学脉冲沉积法在聚苯胺(PANI)膜上制备了纳米CdS/PANI复合膜,并利用扫描电镜光谱、紫外可见光谱、红外光谱、拉曼和荧光等光谱技术表征复合膜的形貌、结构及性质.CdS/PANI复合膜中CdS微粒呈现量子尺寸效应;CdS和PANI间存在相互作用;由于聚苯胺和CdS能级的合适匹配,聚苯胺对CdS的光致发光(PL)有增强效应,增强机理为光生载流子的传递机理.     

Q-CdS/聚合物纳米复合膜的制备与荧光性能

采用配位化学合成原理 ,分离制备出颗粒尺寸小于 10nm的单分散性的Q态CdS(Q CdS)纳米粒子 ,将Q CdS纳米粒子与聚合物复合成膜 ,制备出一系列Q CdS 聚合物纳米复合膜 .用紫外可见吸收光谱与透射电镜研究了纳米复合膜的量子尺寸效应和分散性 .通过荧光光谱探讨了不同聚合物基体材料和不同Q CdS含量的纳米复合膜的荧光发光性能 .结果表明 ,一方面这种以聚合物为基体的纳米复合膜 ,由于聚合物与Q CdS之间的相互作用 ,使纳米复合膜表现出与单一相组分完全不同的特征荧光发射峰 ;另一方面 ,随着纳米复合膜中Q CdS含量的不断增大 ,纳米复合膜的荧光强度不断增强 ,在一定浓度时达到最大值 .     

结合表面引发的原子转移自由基聚合和气/固反应制备CdS纳米微粒/聚苯乙烯核壳微球

结合表面引发的原子转移自由基聚合和气/固反应制备CdS纳米微粒/聚苯乙烯核壳微球. 以表面富含环氧基团的聚苯乙烯微球为基底, 利用开环反应在水相中一步接枝表面引发剂, 然后在聚苯乙烯微球表面引发甲基丙烯酸镉的原子转移自由基聚合, 最后通入H2S气体原位生成CdS纳米微粒. 生成的CdS纳米微粒复合的核壳微球呈草莓状形貌, 且具有良好的光学性能.     

择优生长CdS纳米微粒膜的制备和性能研究

利用恒电流阴极还原法或电流脉冲法在聚苯胺膜、PATP膜、Au膜和ITO基体上制备了CdS纳米微粒膜 ,并对其结构和紫外_可见吸收等性质进行初步表征 .结果表明基体对CdS微粒膜的结构和性能具有较大的影响     

CdS/TiO2复合纳米微粒的原位合成及性质研究

采用一种新方法,在TiO₂表面原位合成CdS纳米微粒,并用红外光谱跟踪了CdS/TiO₂复合纳米微粒的形成过程.紫外吸收光谱研究表明TiO₂对CdS纳米微粒的形成有很好的稳定作用,荧光光谱研究结果表明,这种纳米异质结构有着良好的电荷分离.     

黄色硫化镉纳米粒子的共振瑞利散射光谱研究

在高分子聚乙烯醇存在下 ,Cd2 + 与S2 - 反应生成黄色CdS纳米微粒。当CdS浓度小于 5× 1 0 - 4 mol L时 ,它在 4 70nm产生一个最强RRS峰 ,这是由低浓度较小粒径黄色CdS纳米微粒或黄色CdS分子与光源相互作用的结果 ;当CdS浓度大于 7.5× 1 0 - 4 mol L时 ,在 5 2 0nm产生一个最强的特征RRS峰。黄色CdS纳米微粒体系在可见光区无吸收峰。当CdS纳米微粒的浓度在 7.5× 1 0 - 4 ～ 2 .0× 1 0 - 3mol L范围内 ,所得纳米粒子的粒径为 4 3nm。实验表明 :光源发射强度分布和CdS纳米粒子的形成是产生其RRS光谱峰的主要原因     

Kinetic effect in the size-control of CdS nanoparticles

A new method of size control for CdS nanoparticles, called common cation coprecipitation, is reported. In the course of coprecipitation, both CdS and CdSt_2(cadmium stearate) formations are diffusion-controlled and their rates are quite different. The size of CdS nanoparticles depends on the ratio of initial concentrations of S~(2-) to St~- (stearate ion). Characterized by UV-Vis absorption, XRD, TEM, fluorescence and XPS, the results obtained show that the coprecipitate is a composite, i. e. CdS particle inserts in the CdSt_2 molecular layers to form a sandwich-like structure. The method reported for size control of CdS nanoparticles might be called kinetic self-assembling.     

Electrochemical synthesis of free-standing CdS nanoparticles in ethylene glycol

A novel one-step electrochemical method for the preparation of capping-free cadmium sulfide nanoparticles is described. With gold as the working electrode, capping-free CdS nanoparticles are synthesized very conveniently at 70°C in the ethylene glycol (EG) solution of elementary sulfur, cadmium salt, and supporting electrolyte at −0.1 V. By carefully selecting the reductive potential, elementary sulfur is reduced while the reduction of Cd²⁺ is blocked by the formation of a sulfur monolayer on the gold electrode surface. The produced S²⁻ reacts with cadmium cations in the solution to produce CdS. In this method, magnetic stirring can effectively prevent the deposition of CdS on the electrode surface. XRD analysis indicates that the product is pure cubic-phase CdS. The size and morphology of the particles are studied by TEM. Published in Russian in Elektrokhimiya, 2006, Vol. 42, No. 9, pp. 1060–1064. The text was submitted by the authors in English.     

CdS纳米微粒在LB膜层隙聚集形态的AFM观察

用LB技术制备纳米微粒与超薄有机膜的复合膜是近年来值得注意的研究进展＊．利用该方法所制备出的材料既具有纳米粒子所特有的量子尺度效应，又具有LB股的分子层次有序、股厚可控以及易于组装等特点．它可用来制备结构可控的有机无机交替膜．而且，通过改变LB膜成膜材料和制备条件还可改变纳米粒子的光电特性．因此它在微电子学、光电子学、非线性光学及传感器等研究领域有着十分广阔的应用前景问．纳米微粒的聚集形态及LB膜在生成纳米微粒后的结构变化对材料的特性有着很大的影响．但采用一般的电镜技术或光谱分析手段均不能在实空间和…     

反胶束法合成CdS纳米粒子及其表征

以AOT为保护剂,采用反胶束法合成CdS纳米粒子。利用水洗法洗去保护剂AOT,通过加入不同量的无水乙醇调节分散介质的极性,改变CdS纳米粒子在分散介质中的"溶解度",从而实现不同尺寸粒子的分离。采用紫外-可见(UV-vis)吸收光谱、透射电子显微镜(TEM)、荧光光谱法对其进行表征。     

用硫脲分子表面修饰的CdS纳米粒子的合成和表征

报道了用硫脲分子进行表面化学修饰的CdS纳米粒子的合成方法,并引入了AOT(磺基琥珀酸双-2-乙基己基酯钠盐)作为平衡反离子,进一步对CdS表面作了修饰,增加了CdS纳米粒子在有机溶剂中的稳定性和可分散性。我们还探讨了温度、浓度、pH等因素对合成的影响,并通过TEM、XRD、FT-IR等手段对产物结构进行了表征。所得微粒粒径为5 nm左右,呈球形,硫脲分子与CdS纳米粒子富Cd²⁺表面通过形成Cd-S配位键而修饰在粒子表面。这种表面修饰的CdS纳米粒子将在非线性光学及自组装方面具有优     

Photoinduced Electron Transfer between CdS and CdTe Nanoparticles in Colloidal Solutions

The photochemical behavior of solutions containing a mixture of CdS and CdTe nanoparticles under pulsed irradiation conditions was investigated. It was shown that electron transfer from the CdS particles to the CdTe nanoparticles occurs during the photoexcitation of such systems. The effectiveness of the process is increased with increase in the size of the CdTe nanoparticles. Such behavior is due to decrease in the potential of the CdTe conduction band with increase in the size of the nanoparticles as a result of the appearance of quantum-dimensional effects.     

Preparation of cadmium sulfide nanoparticles in self-reproducing reversed micelles

Octyl octanoate (O-OL) underwent hydrolysis in sodium octanoate (NaOA) reversed micelles in 85:15 = isooctane:octanol (OL) (v/v), containing w = [H2O]/[NaOA] = 40. The products of the hydrolysis, octanoic acid (OA) and octanol (OL), lead to the formation of additional (albeit smaller) reversed micelles; hence the process is considered to be self-reproducing. Self-reproduction was found to be catalyzed by lithium hydroxide, solubilized in the water pools, as well as by hydrogen sulfide, added to the solution of the reversed micelles. Addition of hydrogen sulfide to cadmium perchlorate containing self-reproducing reversed micelles resulted in the formation of cadmium sulfide (CdS) nanoparticles. Diameters of the CdS containing nanoparticles could be altered from 5.4 to 1.8 nm by changing the [Cd2+]/[H2S] ratios from 0.25 to 10. The CdS nanoparticles formed were capped by mercaptopropionic acid, isolated as solids, and could be repeatedly redispersed in water without changing their sizes. Additional CdS nanoparticles were generated in the supernatants removed from the precipitated capped CdS nanoparticles.     

明胶溶液中笤帚状纳米CdS的合成及其光谱特性研究

以明胶为稳定剂, 制备出CdS纳米棒, 并实现其向笤帚状纳米CdS的形貌转化. 扫描电镜(SEM)图像表明, 生长时间为2 d, 样品为棒状结构, 直径为50～140 nm, 长度为150～710 nm; 生长15 d的CdS微晶为笤帚状, 结节点直径340～620 nm, 长度2.7～8.4 μm. 探讨了其形貌转化的原因. 结合红外吸收(IR)和荧光光谱的测试结果, 提出了可能的离子络合转化和定位生长机理. 合成的CdS微晶具有一定的荧光性质, 并在紫外和荧光光谱上均表现出明显的量子尺寸效应.     

Preparation of colloidal CdSe and CdS/CdSe nanoparticles from sodium selenosulfate in aqueous polymers solutions

Cadmium selenide nanoparticles formation at the interaction between CdCl2 and Na2SeSO3 in aqueous solutions of sodium polyphosphate and gelatin has been studied. Structural and optical properties of CdSe nanoparticles have been characterized. It has been shown that the temperature and the ratio of reagents concentrations are the basic parameters, controlling the size of CdSe nanoparticles. Photocatalytic activity of CdS nanoparticles in Na2SeSO3 reduction has been found and investigated; structural and optical properties of binary CdS/CdSe nanoparticles have been characterized. This photoreaction, when carried out in the presence of CdCl2, results in the formation of composite CdS/CdSe nanoparticles. It has been shown that slow interaction of adsorbed selenosulfate with surface-trapped CdS conduction band electrons is the limiting stage of the photocatalytic reaction.     

The influence of DMSO on the formation and photoelectrochemical properties of CdS thin films by electrodeposition method

The homodispersed CdS nanoparticles were prepared on Sn-doped indium oxide substrates (ITO) to form smooth and uniform CdS thin films by electrodeposition method from a dimethyl sulfoxide (DMSO) solution containing cadmium chloride and sulfur. The structure and morphologies of samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. The results indicate that DMSO played an important role in formation of CdS nanofilms by affecting the nucleation and growth of the CdS nanoparticles. So, a DMSO-assisted growth process was proposed as a plausible mechanism for the formation of smooth and uniform CdS nanofilms. According to the photoelectrochemical test, the CdS thin film prepared in 30 % DMSO + 70 % H₂O system exhibited maximum photocurrent and open circuit potentials. This is because the deposited CdS nanoparticles had better dispersity on ITO, which facilitated the propagation and kinetic separation of photogenerated charges.