CdS纳米粒子制备的影响因素及 CdS纳米粒子-酚藏花红体系的光谱特性

室温条件下在水溶液中合成了粒度分布均匀、分散性好的CdS纳米粒子. 研究了pH值、反应时间等条件因素对其吸收光谱和荧光光谱特性的影响, 并探讨了CdS纳米粒子-酚藏花红体系的光谱特性、可能的作用机理和应用前景.     

树状大分子保护的CdS纳米粒子的合成与表征

以聚酰胺-胺型树状大分子（PAMAM）为保护剂,在水溶液中制备了不同粒径的CdS纳米粒子,分别考察了PAMAM的代数以及保护剂与CdS物质的量比对CdS纳米粒子大小及荧光性能的影响.利用紫外-可见光谱、荧光光谱、透射电子显微镜对其光学性能和结构进行了表征.     

CdS/TiO2复合纳米粒子的光学性质

在Brij35/正己醇/环己烷/水构成的反相微乳体系中，分别合成了CdS、TiO2纳米粒子和TiO2包覆CdS（CdS/TiO2）的复合纳米粒子.测定了它们的紫外-可见吸收和荧光光谱.结果表明， CdS/TiO2复合纳米粒子在可见光区的吸收比相应的两组分的吸收之和更强.纳米CdS和纳米TiO2均有较强的荧光.而且在相同浓度时纳米TiO2的荧光比纳米CdS的荧光更强.但在CdS/TiO2复合纳米粒子中，TiO2的荧光被淬灭，而CdS的荧光稍有降低.     

CdS纳米粒子与半胱氨酸相互作用的研究

合成了粒径均匀和分散性好的CdS纳米粒子.通过改变CdS纳米粒子及半胱氨酸的浓度、体系的pH值及CdCl2和CH3CSNH2摩尔比等实验条件跟踪监测了CdS纳米粒子光谱性质的变化,探讨了CdS纳米粒子与半胱氨酸之间的相互作用及化学反应机理.     

DNA/CdS纳米粒子复合体系的光谱和光电化学性质

在水溶液中以DNA作为模板和稳定剂, 构筑了DNA与CdS纳米粒子复合体系(DNA/CdS NPC), 研究DNA的含量, 单双链等对复合体系光电响应的影响, 并综合TEM, UV-Vis, IR和荧光光谱等对其形貌和光谱性质进行表征. 结果表明, CdS纳米粒子(CdS NPs)与DNA链之间主要通过静电作用结合; DNA模板对CdS NPs的禁带宽度没有影响; 以DNA模板合成的CdS NPs具有较高的表面态密度, 其对CdS NPs的荧光有增强作用, 而对光电流响应有抑制作用, 并且DNA在复合体系中的含量影响荧光增强和光电流减弱的程度. 该复合体系在荧光标记检测和DNA的定量分析方面可能具有应用前景.     

水溶性CdSe/CdS核壳纳米粒子制备的影响因素及其对CdSe/CdS光谱特性的影响

以半胱氨酸镉配合物为前体, 在水溶液中合成CdSe纳米粒子, 以CdS对其表面进行修饰, 得到具有核壳结构的CdSe/CdS 纳米粒子. 采用XRD, TEM表征其结构及形貌; 以荧光光谱研究了时间、pH值、壳量、壳前体加入方式、稳定剂用量等因素对CdSe/CdS光谱特性的影响.     

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 .     

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。     

甲苯-乙二醇两相界面反应合成CdS纳米粒子

以十八胺为表面修饰剂,硬脂酸镉和硫脲为前驱物,在甲苯-乙二醇两相界面处合成了CdS纳米粒子.研究了反应时间、前驱物浓度、前驱物和表面修饰剂摩尔比等因素对合成CdS纳米粒子的影响.采用紫外-可见吸收光谱、荧光光谱、透射电子显微镜(TEM)和广角X射线衍射(WAXD)等方法对CdS纳米粒子的光学性质、形貌及晶体结构进行了表...     

CdS量子点与CdSe量子点间荧光共振能量转移研究

在有机相中合成了不同尺寸的CdS和CdSe量子点, 并利用Langmuir-Blodgett (LB)技术将相同尺寸的CdS和CdSe量子点组装成多层复合纳米有序结构. 采用荧光光谱研究了CdS和CdSe量子点在混合体系和多层复合纳米有序结构状态下的荧光共振能量转移(Fluorescence resonance energy transfer, FRET). 我们观察到CdS和CdSe量子点混合溶液与当溶剂挥发形成固态膜中, CdS量子点的荧光强度较溶液状态下强烈猝灭, 表明当颗粒间距离减小时CdS和CdSe量子点间产生较高效率的荧光共振能量转移. 在多层复合纳米有序结构中, 随着给体CdS量子点层数的增加, 单层受体CdSe量子点的荧光逐步增强, 这表明层间纵向能量转移率随给体层数的增加而提高.     

Fluorescence quenching of bovine serum albumin.

The fluorescence emission spectra and 3D fluorescence spectra of bovine serum albumin (BSA) in cetyltrimethylammonium bromide (CTAB) reversed micelles were affected by the microenvironment. Blue shifts of the fluorescence emission peaks were found when BSA was present in CTAB reversed micelles. The fluorescence intensity changed with the water content. Similar changes in the peak regions of the 3D fluorescence spectra were also observed. CdS nanoparticles prepared in CTAB reversed micelles quenched the fluorescence of BSA significantly. The fluorescence of BSA was more effectively quenched by negative CdS nanoparticles than by positive or neutral CdS ones. The quenching degree increased linearly with increasing the concentration of negative CdS nanoparticles over the range of 5.0 x 10(-6) - 3.0 x 10(-5) mol L(-1). The quenching mechanism is discussed and the quenching constant is 1.32 x 10(4) L mol(-1).     

Regional variation of sediment load of Asian rivers flowing into the ocean

CdS, CdS:Mn, ZnS, ZnS:Mn and ZnS:Tb nanoparticles were prepared by using carboxylic-containing copolymer, polystyrene-maleic anhydride (PSM), as template. Average particle size, 2.5 nm for CdS nanoparticles, is deduced from UV-vis absorption spectra and consistent with the observation of TEM. Characteristic emissions of the doping ions can be observed and the energy transfer from the host to the doping ions is verified. Fourier transform infrared (FTIR) spectra were studied to confirm the bonding effect of the copolymer and the metal ions. PSM hydrolyzed and chelated metal ions by its carboxylic group, and then performed as a protection layer after the formation of nanoparticles.     

The Effects of Methylene Blue on the Optical Properties of Nanometer-sized CdS Organosol

The inverse micelle system of nanometer-sized CdS doped with Methylene Blue(MB) was synthesized and characterized by using absorption and fluorescence spectra. The results show that MB molecules were absorbed onto the surface of CdS nanoparticles and interacted with surfactants when its concentration was lower than 4×10^-6 mol/L. From the comparison of their spectra, MB molecules by adsorption have a strong quenched fluorescence emission of CdS nanoparticles with surface defect states. All responses and main mechanism are ascribed to the charge transfer between the CdS organosol and Methylene Blue molecules.     

Synthesis,Separation, and Characterization of Au@CdS Nanoparticles

The mixture of Au@CdS and CdS nanoparticles were obtained by reversed micelles method. n-Dodecanethiol was used to replace dioctylsulfosuccinate sodium salt (AOT) as a protector, and the surfactant AOT was washed away by water. By adding enthanol of different quantity, the polarity of dispersed medium was regulated and the solubility of Au@CdS and CdS nanoparticles in dispersed medium was adjusted. Consequently, the Au@CdS and CdS nanoparticles were separated effectively. Ultraviolet absorption spectra, transmission electronic microscopy (TEM), energy-dispersive X-ray analysis (EDX), and fluorescence spectra were used to characterize Au@CdS nanoparticles.     

微波萃取高效液相色谱法测定口红中芳香胺类化合物

利用微波萃取高效液相色谱法测定了口红中芳香胺类化合物.先将口红涂于玻璃片上,然后用微波萃取和高效液相色谱法测定萃取液中的芳香胺类化合物.研究了3种市售口红并得到了芳香胺类化合物的定量测定结果.考察了微波萃取的条件,并将薄层色谱等萃取分离方法和微波萃取法进行了比较,证明微波萃取法在萃取膏状物和蜡状物中的组分时,具有比其它方法更加方便、快速等优点.     

表面修饰CdS和(CdS)ZnS纳米晶的性能研究

在水相中合成了CdS纳米微粒,以ZnS对其进行表面修饰,得到具有核壳结构的(CdS)ZnS水溶性纳米晶。采用红外光谱、X射线衍射(XRD)、透射电镜(TEM)表征其粒度和形貌,紫外-可见吸收光谱(UV)、荧光光谱表征其光学特性。制得的CdS近似呈球形,直径为8nm;CdS纳米颗粒表面经ZnS修饰后,其荧光发射峰强度显著增强,表面态发射减弱。     

Different Interactions between Isomeric Tetrakis-(N-Hexadecylpyridiniumyl) Porphyrins and CdS Nanoparticles

Using porphyrin amphiphiles TC(16)PyP(2), TC(16)PyP(3), and TC(16)PyP(4) as photosensitizers, the interaction between amphiphilic porphyrins and colloidal CdS nanoparticles was studied by observing their absorption spectra, fluorescence spectra, and fluorescence lifetimes. The experimental results reveal that upon addition of CdS nanoparticles to a TC(16)PyP(3) or TC(16)PyP(4) solution, TC(16)PyP(3) or TC(16)PyP(4) is adsorbed onto the surface of the colloidal nanoparticles due to electrostatic action. The absorption spectra display the characteristic absorption of metalloporphyrin. Moreover, this adsorption also leads to red-shifted fluorescence spectra and the quenching of fluorescence emission. These changes are related to the formation of complexes. Nearly 90% of the fluorescence emission of 5x10(-6) mol/L TC(16)PyP(4) can be quenched with 6.8x10(-4) mol/L CdS colloid nanoparticles. Only 60% of the fluorescence emission of 5x10(-6) mol/L TC(16)PyP(3) can be quenched with 6.8x10(-4) mol/L CdS nanoparticles. The fluorescence quenching is attributable mainly to static quenching. According to the fluorescence quenching curves, the apparent association constants of TC(16)PyP(4) and TC(16)PyP(3) with colloidal CdS nanoparticles are 1.42x10(3) (mol/L)(-1) and 6.76x10(2) (mol/L)(-1), respectively. However, TC(16)PyP(2) does not adsorb onto the surface of colloid nanoparticles due to its larger steric hindrance; its absorption and fluorescence spectra are unchanged. Copyright 2000 Academic Press.