绿色银纳米粒子的共振散射光谱研究

以柠檬酸钠作光还原剂,采用紫外光-可见光二步光化学法制备了绿色银纳米离子,在399.4nm和691.5nm处有二个紫外-可见吸收峰;在340nm,470nm和520nm处有三个共振散射峰,从超分子和纳米粒子这一整体出发,探讨了共振散射光谱产生的原因及银超分子光反应机理。     

绿色银纳米粒子的共振散射光谱研究

以柠檬酸钠作光还原剂,采用紫外光-可见光二步光化学法制备了绿色银纳米离子,在399.4nm和691.5nm处有二个紫外-可见吸收峰;在340nm,470nm和520nm处有三个共振散射峰,从超分子和纳米粒子这一整体出发,探讨了共振散射光谱产生的原因及银超分子光反应机理。     

聚丙烯酰胺存在下微波高压合成银纳米粒子及其光谱特性

以聚丙烯酰胺为还原剂和稳定剂 ,采用微波高压液相合成法制备了黄色银纳米粒子。用吸收光谱和共振散射光谱研究了其制备条件的影响。在 4 2 1.6nm处产生最大吸收峰 ,在 4 70nm处产生一个最强共振散射峰。实验表明 :该法制备的银纳米粒子粒径均匀 ,平均粒径为 6 6nm ,其稳定性和分散性较好 ,合成方法简便、快捷。     

Ag-CV的表面增强共振散射光谱研究

采用共振散射光谱和紫外可见光谱研究了银胶与结晶紫的相互作用。在ＰＨ为４．０的ＨＡｃ－ＮａＡｃ缓冲溶液中,奶胶在３４５ｎｍ和７００ｎｍ有两个共振散射峰;当加入带下辈民的阳离子染料结晶紫后,产生表面增强效应,３４５ｎｍ和７００ｎｍ处的共振散身信号大为增强,从而获得灵敏的表面增强共振散射光谱。     

聚丙烯酰胺存在下微波高压合成银钠米粒子及其光谱特性

以聚丙烯酰胺为还原剂和稳定剂，采用微波高压液相合成法制备了黄色银钠米粒子。用吸收光谱和共振散射光谱研究了其制备条件的影响。在421.6nm处产生最大吸收峰，在470nm处产生一个最强共振散射峰。实验表明：该法制备的银钠米粒子粒径均匀，平均粒径为66nm，其稳定性和分散性较好，合成方法简便、快捷。     

液相卤化银纳米微粒的界面荧光和共振散射光谱特性

液相卤化银纳米微粒的共振散射光谱和发射光谱表明，AgCl和AgBr纳米微粒均在330，400，470和680nm处产生4个共振散射峰，在340，400和470nm处产生三个荧光峰．Ad纳米微粒在340，400，437，470和680nm处产生5个共振散射峰；除在340，400和470nm处产生3个荧光峰外，在434nm处有一最强的荧光峰．卤化银纳米微粒体系的浓度对共振散射信号的影响与浓度对荧光强度的影响一致，Aga，AgBr和AgI体系的共振散射光信号强度分别约为荧光信号的110，130和80倍，即荧光与共振散射之间存在相关性．提出了液相AgX纳米微粒荧光产生机理，解释了荧光与共振散射之间存在相关性的原因．     

维生素E绿色还原法制备银纳米粒子的研究

采用一种绿色还原法制备银纳米粒子,以维生素E为还原剂,淀粉为稳定剂,在液相中还原硫酸银,通过改变溶液的pH值和反应时间,得到不同粒径的黄色银纳米粒子,并分别采用透射电镜、红外光谱、紫外-可见吸收光谱、扫描电镜和电化学方法对银纳米粒子进行表征。结果表明:维生素E在溶液中被氧化生成苯醌,反应得到的银纳米粒子为球形,粒径为8~25 nm;在较强碱性条件下,得到的银纳米粒子尺寸较小,分布较均匀,其平均粒径约为10 nm;不同条件下生成的银溶胶分别在417、411、409、408 nm处出现紫外吸收峰,这些吸收峰均为银纳米粒子的表面共振吸收;生成的银纳米粒子具有很好的电化学性质,并对L-半胱氨酸的电化学反应显示了良好的催化活性。     

银(Ⅰ)-苯羟乙酸光反应的共振散射光谱研究

在 0 .0 4mol/LH2 SO4 0 .0 1mol/L苯羟乙酸介质中 ,Ag+ 被紫外光还原生成银胶 ,苯羟乙酸被光氧化生成苯甲醛。银胶于 5 2 5nm处产生一灵敏的共振散射峰 ,银浓度在 0 .1～ 4.0 μg/mL范围内与共振散射光强度呈良好线性关系。方法的检出限为 0 .0 5 μg/mL。该法已用于废水中银的测定。并采用共振散射光谱、紫外可见吸收光谱及示波极谱等探讨了光化学反应机理和共振散射现象     

表面吸附质对银亚胶体吸光特性的影响

纯银溶胶在390nm处有一吸收峰。当银溶胶吸附了1-苯基-5-巯基四氮唑(PMT)或2-巯基苯骈噻唑(MBT)时, 银溶胶由亮黄色转变为橙红色, 即在510～550nm处出现一个新的吸收峰。研究发现, 卤素离子在银溶胶颗粒上与PMT和MBT有竞争吸附作用。但是卤离子对银溶胶的光谱吸收的影响完全不同于PMT和MBT。在讨论这种差别时应首先考虑金属银溶胶颗粒表面性质因吸附不同物质所产生的变化。     

AR-Ag(Ⅰ)体系的共振散射光谱法测定痕量银

在pH=4.4的NaAc-HAc缓冲介质和2.0×10-3mol/L十二烷基苯磺酸钠(SDBS)溶液中,Ag(Ⅰ)与茜素红(AR)可形成较稳定的离子缔合物微粒,其在324、360和500nm处分别产生3个较强的共振散射峰.在最佳实验条件下,浓度在0.022～2.160μg/mL之间的Ag(Ⅰ)与共振散射强度△I324nm呈较好的线性关系,检测限为0.139 ng/mL.据此,建立了一种测定痕量银的共振散射新方法,并将该方法用于废胶片中痕量银的测定.     

Resonance light scattering properties of Eu3+ in gold colloid

Gold colloidal containing rare-earth ions Eu3+ were prepared at room temperature. Fluorescence spectra and resonance light scattering (RLS) spectra of Eu3+ ions and gold colloid containing Eu3+ were measured. For solution containing Eu3+, RLS features show two peaks at the edges of the visible light wavelength region. The short wavelength peak takes place at about 400 nm and the longer wavelength peak is the corresponding 1/2 fraction frequency RLS peak, which takes place at about 780 nm. When gold colloids were added to the solution containing Eu3+, both these two RLS peaks were enhanced. We believe that the energies, which are absorbed by the surface plasmon resonance in the gold nanoparticles, are efficiently transferred into the Eu3+ ions to cause the increased scattering.     

超细颗粒卤化银的制备与稳定性

卤化银微晶体是一种典型的与成像材料相关的无机微粒子。一个多世纪以来,它所特有的光敏性能使之在成像科学领域中一直占据着重要的地位。近二十年来,纳米粒子化学和物理的迅速发展对于推动成像科学技术前进产生了不可低估的影响。纳米级超细颗粒卤化银的制备与性能研究十分活跃,它不仅对于深入认识卤化银成像机理具有重要意义,而且在形成新的特殊照相材料如超高解像力照相材料等方面起着关键性作用。超细颗粒卤化银的制备方法基本上可概括为两种,即直接反应法与间接反应法。前者是在某种保护性介质中同时注入银盐与卤盐,使之直接反应…     

Resonance scattering spectral analysis of chlorides based on the formation of (AgCl)n(Ag)s nanoparticle

A novel resonance scattering spectral method has been proposed for the determination of trace amounts of chlorides in the range of 2 x 10(-7)-8 x 10(-6) mol/l. It was based on the photochemical reaction system of AgNO3-NaCl-sodium oxalic to form the (AgCl)nucleus (n)(Ag)shell (s) nanoparticle. There is a strongest resonance scattering peak at 470 nm and a maximum absorption peak at 425 nm. The concentration of chlorides is proportional to the intensity of resonance scattering at 470 nm. The nonlinear resonance scattering peaks of the nanoparticle system have been also considered, according to the theory of the interaction between the surface electron of nanoparticle and the incidence photon.     

(PtI6-2RDG)n缔合纳米微粒体系的共振散射、荧光猝灭和减色效应研究

在0.02mol/L HCl介质中，罗丹明6G（RDG）分别在530nm和550nm处有一个吸收峰和荧光峰，PtI6^2-与RDG^ 主要通过静电引力形成疏水性的PtI6-2RDG缔合物分子。PtI6-2RDG分子间存在较强的分子和和疏水作用力而生成（PtI6-2RDG)n缔合纳米微粒，其粒径为40nm，在400nm、470nm和590nm产生3个共振散射，其中400nm和590nm处的2个峰为其特征共振散射峰，550nm荧光峰和530nm吸收峰的降低是由于纳米微粒形成后，只有裹露在（PtI6-2RDG)n纳米微粒界面的RDG荧光分子才能吸收激发光子跃迁到激发态，进而返回基态产生荧光，而体体相的RDG荧光分子无法与激发光作用产生荧光，即与激发光作用的RDG分子数大为降低。当该纳米微粒体系加入乙醇后，由于乙醇致使（PtI6-2RDG)n纳米微粒分解为PtI6-2RDG分子，体系的红紫色和共振散射峰消失，吸收峰和荧光峰恢复，研究结果表明，红紫色（PtI6-2RDG)n纳米微粒的形成是其共振散射增强、荧光猝灭、减色效应和产生特征共振散射峰的根本原因。     

氯金酸-罗丹明S缔合纳米微粒体系的共振散射增强与荧光猝灭研究

在0．2mol/L HCl介质中，罗丹明S(RDS)分别在520nm和550nm处有一个吸收峰和荧光峰。当有Au(Ⅲ）存在时，Au（Ⅲ）与Cl^-形成AuCl4^-，AuCl^-与RDS^ 借助于静电引力形成疏水性的AuCl4-RDS缔合物分子。AuCl4-RDS分子间存在较强的分子间作用力和疏水作用力而生成(AuCl4-RDS)。缔合纳米微粒，粒径为45nm。在360nm产生瑞利散射峰，在600nm产生共振散射峰。由于纳米微粒形成后，只有裹露在(AuCl4-RDS)n纳米微粒界面的RDS荧光分子才能吸收激发光子跃迁到激发态，进而返回基态产生荧光。而体相的RDS荧光分子无法与激发光作用产生荧光，即受激RDS分子数大为降低，故550nm荧光峰和520nm吸收峰的降低。当缔合纳米微粒体系加入乙醇后，体系的红紫色和共振散射峰消失，吸收峰和荧光峰恢复，由于乙醇致使(AuCl4-RDS)。纳米微粒分解为AuCl4-RDS分子。结果表明：红紫色(AuCl4-RDS)n纳米粒子的形成是其共振散射增强、荧光猝灭和产生共振散射峰的根本原因。     

Luminescence effect of silver nanoparticle in water phase

Yellow silver nanoparticles in water phase were prepared by microwave synthesis method. Study found that there is a fluorescence peak at 465 nm and a strongest resonance scattering peak at 460 nm for the nanoparticles. The resonance scattering intensity at 465 nm I(460 nm). fluorescence intensity at 465 nm F(465)(nm) and absorbance at 455 nm A(455 nm) were found linear to the concentration c(Ag) in the range from 0 to 3.5x10(-4)mol/L Ag, with linear regression equation for I(460 nm)=48.1x10(4) c(Ag)+3.69 and F(465 nm)=28.7x10(4)c(Ag)+3.50 and A(455 nm)1.23x10(4)c(Ag)+0.01, their regression coefficient for 0.9976, 0.9954 and 0.9957, respectively. When the c(Ag) was over 3.5x10(-4)mol/L, the resonance scattering peak and fluorescence peak of 465 nm take place red-shift and display luminescence quenching, but the absorption peak place does not change and the absorption intensity enhances. The paper reports the spectral properties of silver nanoparticles in water phase, and offers the principle of interface luminescence electron to state the luminescence effect of silver nanoparticles.     

Change Color Effect and Spectral Properties of Gold Nanoparticle-cationic Surfactants System

The change color effect of gold nanoparticle solutions was studied by means of resonance scattering and absorption spectrometry and scan electron microscopy. The red Au nanoparticles with a size of 10 nm exhibit a resonance absorption peak and a resonance scattering peak all at 525 nm. After some inorganic electrolyte was added to a red Au nanoparticles solution, the color of the solution became blue and the absorbance at 600-700 nm was significantly increased. The ratio of the concentration of rnonovalent cations, at which the resonance scattering of the system at 525 nm is maximal to that of divalent cations, is in the range of 100 : 1--100 ; 1. 8. It is in good agreement with the Schulze-Hardy rule of the coagulation value of electrolyte. After adding some cationic surfactants to the above solution, the color of the solution is in deep blue, with two resonance absorption peaks at 550 and 680 nm, and a greatly enhanced resonance scattering peak at 525 nm. The experiments demonstrate that the stronger the hydrophobicity of the cationic surfactant is, the stronger the change color effect of the Au nanoparticle solution promoted by cationic surfactant is. The change color effect of Au nanoparticle solution is resulted from the increased diameter of Au nanoparticles, and the changes of resonance absorotion DeaR and resonance scattering.