银－金红石复合纳米微晶的光谱性能

λ>330nm光照射含有金红石型TiO2微晶颗粒的AgNO3溶液,制备出了Ag-TiO2复合超微粒子,与纯的银溶胶相比,复合粒子上银的等离子体吸收峰宽化红移,位于400～600nm。这种复合超微粒子的溶胶,表现出表面增强拉曼散射(SERS)效应。吸附-共振增强可用来解释Ag-TiO2复合粒子的SERS效应。     

银/二氧化硅核壳纳米颗粒的制备及其壳层厚度对其光学性质的影响

通过溶胶-凝胶法,制备了银/二氧化硅核壳材料(Ag@SiO2),对SiO2壳层厚度进行了有效调控,并系统研究了壳层厚度对银的等离子体共振峰(LSPR)以及对折射率灵敏度(RIS)的影响。研究结果表明,随SiO2壳层包覆厚度的增加,银纳米颗粒的LSPR吸收峰呈现先红移后蓝移的规律。对于粒径为50 nm的银纳米颗粒,当SiO2壳层达到65 nm时,LSPR最大吸收波长为465 nm。进一步增加SiO2壳层厚度,LSPR发生蓝移并且强度变弱,当SiO2壳层达到120 nm时,LSPR吸收峰已无法清晰辨认。研究了Ag@SiO2材料的RIS效应,发现随着SiO2厚度的增大RIS效应逐渐变小。     

1-苯基-5-巯基四氮唑和苯并三氮唑在胶态银和硫化银上的阳极抑制效应

为了研究抑制剂对银核和硫化银核的不同作用 ,本工作考察了 1 苯基 5 巯基四氮唑 (PMT)和苯并三氮唑 (BTA)作为抑制剂在银核和硫化银核上物理显影的阳极抑制和解抑制效应 .实验结果表明 :1 )PMT和BTA对Ag核和银离子过量时制得的硫化银核 ,Ag2 S(Ag) ,的显影催化活性都有不同程度的抑制作用 ,而对硫离子过量时制得的硫化银核 ,Ag2 S(S) ,无明显的抑制作用 ,这可能是由于过量硫离子在硫化银核上的吸附要强于这两种抑制剂 ;2 )S2 O32 - 或I- 离子的存在对BTA在Ag核上有解抑制作用 ,不仅可恢复甚至提高Ag核的显影催化活性 ,而对Ag2 S核的抑制作用无明显影响 ;3)与BTA不同 ,S2 O32 - 或I- 离子对PMT在Ag核上没有解抑制作用 ,对Ag2 S(Ag)核的抑制作用还稍有增强 ,而对Ag2 S(S)核稍有减弱 ;4 )银溶胶中的表面增强拉曼谱 (SERS)测量证实 :BTA在Ag核上的吸附导致Ag核显影催化活性的下降 ,加入S2 O32 - 或I- 离子后致使BTA的SERS信号消失则意味着BTA在银核表面的脱附 .以上这些结果说明阳极抑制机理在抑制效应中有重要作用     

离子液体中纳米TiO2/聚3-甲基噻吩复合膜的制备及性质研究

采用溶胶凝胶法制成了纳米TiO2电极,在离子液体中将其应用于3-甲基噻吩的电化学聚合,采用循环伏安法(CV),在线紫外可见光谱(UV-Vis),扫描电镜(SEM)和电化学阻抗谱(EIS)对TiO2/聚3-甲基噻吩(TiO2/PMT)复合膜进行了表征并研究了其电化学性质.实验证明,不论是用循环伏安法,恒电位,还是恒电流方法,都能在电极上得到聚3-甲基噻吩(PMT)膜,并伴随有明显的掺杂和去掺杂过程.对应的在线紫外可见光谱上,也出现了氧化和还原两种不同的吸收状态,还原(去掺杂)过程中在480 nm处有一个吸收峰,而氧化(掺杂)过程中此峰消失,取而代之的是一个可见光区的逐渐增强的吸收.PMT膜是P型半导体,TiO2是n型半导体,两者之间能够形成p-n异质结,使光电转换效率得以提高.SEM给出了TiO2电极和聚合物修饰的TiO2的形貌图,电极的交流阻抗谱则从一个角度说明了聚合物膜修饰电极的导电性.     

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。     

Yb(Ⅲ)、Gd(Ⅲ)与EHPG配合物的光谱研究

在0.01mol·L^-1 N-2-羟乙基哌嗪-N′-2-乙磺酸(Hepes),pH 7.4和室温条件下,应用荧光光谱和紫外差光谱研究了Yb(Ⅲ),Gd(Ⅲ)与N-N′-乙烯-二[2-(2-羟基苯基)甘氨酸](EHPG)的配合反应。结果表明,随着稀土离子Yb(Ⅲ)或Gd(Ⅲ)的不断滴加,EHPG在310nm处的最大荧光峰强度逐渐降低,而其紫外差光谱在238和292nm处的吸收峰逐渐增强,当稀土离子Yb(Ⅲ)或Gd(Ⅲ)达到一定量时,310nm处的荧光强度、238和292nm处的吸收峰强     

银纳米颗粒的合成及其与曙红Y的相互作用

分别制备了以L-半胱氨酸(L-cyst.)或以巯基乙酸(TGA)保护的银纳米颗粒,并用紫外-可见分光光度法和透射电子显微技术(TEM)对两种不同状态的银纳米颗粒的结构作了表征。由其吸收光谱图显示,L-cyst.和TGA保护的银纳米颗粒的吸收峰依次位于384 nm和392 nm波长处;由TEM的检测结果表明:上述2种形态银纳米颗粒的粒度大小依次在10~40 nm和20~30 nm范围内。试验中发现,以L-cyst.保护的银纳米颗粒与曙红Y之间有明显的相互作用,导致其吸收峰从384 nm红移至395 nm;以TGA保护的银纳米颗粒与曙红Y之间未见有相互反应。初步探讨了其作用机理,认为系由于结合于银纳米颗粒表面的L-半胱氨酸分子所带的正电荷与曙红Y分子上的负电荷之间的静电作用的结果。     

THE CHARACTERIZATION OF SILVER SUBCOLLOID USED IN SURFACE ENHANCED RAMAN SPECTROSCOPY

A clear light-yellow silver sol which has the visible spectral absorption at 390 nm, when adsorbed phenylmercaptotetrazole(PMT) or mercaptobenzothiazole(MBT), has a new absorption at 510-550 nm. It was found that the adsorption of halide ions competes with PMT and MBT. However, halide ions have a completely different influence from PMT and MBT on the spectral absorption of the silver sol. The differences may result from the change of the properties of the surface of the silver subcolloidal particles and from the bond forms combining adsorbates with the substrates.     

绿色和黄色银胶的光化学制备及其共振散射光谱研究

研究了不同光源、光照时间、反应物浓度等对绿色银胶形成的影响 ,分别制备了绿色银胶和黄色银胶 .透射电镜显示 ,它们的平均粒径分别为 1 0 0nm和 4 0nm .绿色银胶在 393 9nm和 71 3 3nm处有两个吸收峰 ;黄色银胶在 4 1 9 3nm处有一较宽的吸收峰 .它们的最强共振散射峰位于 4 70nm处 ;绿色银胶在 34 0nm和 680nm还有两个小共振峰 .     

Comparison of the adsorption orientation for 2-mercaptobenzothiazole and 2-mercaptobenzoxazole by SERS spectroscopy

In this study, the adsorption orientation for 2-mercaptobenzothiazole (MBT) and 2-mercaptobenzoxazole (MBO) on to silver mirror and silver sol substrates have been studied by surface enhanced Raman scattering (SERS). The MBT and MBO were chemisorbed on both silver mirror and silver sol after deprotonation with a tilted orientation to the silver surfaces. The surface enhanced properties of MBT and MBO showed that the substrate of silver mirror was superior to the sliver sol. The SERS spectra of MBT and MBO revealed that both of the MBT and MBO were adsorbed on silver surfaces strongly by a common sulfur molecule and a sulfur atom from MBT and an oxygen atom from MBO. Therefore, the adsorption orientation of MBT and MBO was little tilted perpendicularly to the silver surfaces. The adsorption geometry did not undergo any significant changes in acidic and basic solutions. It showed that the adsorption orientation for MBT and MBO were stable in the both solutions.     

Rapid detection of Rosa laevigata polysaccharide content by near-infrared spectroscopy

We have investigated surface-enhanced Raman spectroscopy (SERS) spectrum of Omethoate (O,O-dimethyl-S-methylcarbamoylmethylthiophosphate). It is found significant signals in the ordinary Raman spectrum for solid-state Omethoate as well as strong vibrational signals absorbed on the silver sol surface which is prepared by γ-irradiation technique at a very low concentration. Effects of pH and anions (Cl-, Br-, I-) on the adsorption orientation are investigated as well. Two different adsorption mechanisms are deduced, depending on the experimental conditions. The sulfur atom or the sulfur and two oxygen atoms are adsorbed onto the silver sol surface. Among halide ions, Br- and I- are more strongly adsorbed onto the silver sol surface. As a result, the adsorption of Omethoate is less effective due to their steric hindrance.     

Synthesis of anisotropic silver nanoparticles and investigation of their sensory properties

A simple procedure has been proposed for synthesis of planar triangular silver nanoparticles. Optimal conditions have been determined for particles to form, and the particles have been characterized by physicochemical methods. The halide-ion-sensory properties of sols of anisotropic silver nanoparticles prepared in different ways have been studied; sensitivity to halide ions is based on the changes in positions and intensities of longitudinal surface plasmon resonance (SPR) peaks in the range 500–800 nm in the optical absorption spectra of solutions.     

新型中空卤化银颗粒乳剂的制备和性能研究V.中空卤化银T颗粒乳剂的制备和性能研究

８０ 年代以来,许多新型的卤化银微晶已在新开发的各种高质量感光材料中得到应用．近十年来在国内外文献中又出现新型中空卤化银微晶制备方法的报道．本文着重研究一种表面有许多小孔及凹坑的中空卤化银Ｔ颗粒的制备方法和感光性能．由于其独特的孔洞结构,使位错、缺陷增加,填隙银离子浓度增加和电子陷阱增多,潜影形成效率提高,从而达到提高乳剂感光性能的目的．     

异烟酸在银溶胶上的表面增强喇曼散射及影响因素

本文研究了异烟酸吸附在银溶胶表面的表面增强喇曼散射(SERS)光谱以及卤素离子、溶液pH值及溶液浓度对异烟酸SERS光谱的影响。文章提出了离子在银溶胶表面的吸附方式,即主要以—COO~-端吸附于银溶胶表面。最后,对所述实验现象作了定性讨论。     

Features of light absorption of gold nanoparticles bound to the surface of silver by a bridge structure containing Zr(IV) ions

A study was carried out on the optical properties of multilayered surface structures obtained by the coordination binding of gold nanoparticles to a silver surface by Zr(IV) ions. Such a system displays high absorption capacity in a broad spectral range (200-2000 nm), which is observed visually as an ultra-black coating. A physical interpretation of this effect is attributed to an interaction between plasmon excitations on the silver surface and the gold nanoparticle film separated by a dielectric bridge structure consisting of d-metal ions.     

Surface-enhanced Raman scattering study of riboflavin on borohydride-reduced silver colloids: Dependence of concentration, halide anions and pH values

The influences of concentration, halide anions and pH on the surface-enhanced Raman scattering (SERS) of riboflavin adsorbed on borohydride-reduced silver colloids were studied. The optimum concentration for the SERS of riboflavin is 10(-6)mol/L while the SERS enhancement varies for different modes. The addition of 0.2mol/L halide (NaCl, NaBr, and NaI) aqueous solutions, leads to a general decrease of the SERS intensity and a change of spectral profile of riboflavin excited at 514.5nm. Riboflavin interacts with the silver surface possibly through the CO and N-H modes of the uracil ring. The SERS spectra of riboflavin were recorded in the 3.4-11.6 pH range. By analyzing several SERS marker bands, the protonated, deprotonated or the coexistence of both molecular species adsorbed on the colloidal silver particles was proved.     

Study on the interaction of platinum(IV), gold(III) and silver(I) ions with DNA

Fluorescence, absorption spectra have been produced by the interaction of platinum(IV), silver(I) and gold(III) ions with the berberine–DNA system (berberine, Scheme 1). Platinum(IV) and gold(III) ions show different effects from that of silver(I) ion on the spectral characteristics of the berberine–DNA system. Quenching fluorescence is seen with platinum(IV) and gold(III) ions addition, whereas increasing fluorescence is observed for silver(I) ions. The addition of gold(III) and silver(I) ions cause an increase in absorption of the berberine–DNA system. The above results suggest that different metal ions exhibit different affinities when binding to DNA correlates well with the ions’ charge, structure and the coordination ability.     

琥珀酸二异辛酯磺酸钠微乳体系中纳米银的制备及其连续相的影响

在琥珀酸二异辛酯磺酸钠(AOT)为表面活性剂、环己烷为连续相形成的微乳体系中, 利用水合肼还原AgNO₃制备了分散性良好的纳米银. 利用紫外-可见(UV-Vis)光谱和透射电镜(TEM)对所得产物进行了表征, TEM显微图像表明形成粒子为球形结构, 平均粒径为5.10 nm, 标准偏差为2.84 nm. 分别利用正己烷、正庚烷、正辛烷、环己烷和十二烷等作连续介质, 研究了微乳液中连续相对纳米银形成的影响. 随着正烷烃碳链长度的增加, 微乳液中胶束之间的交换速率增大, 形成粒子的平均粒径逐渐减小. 十二烷形成的微乳体系制备的纳米银溶胶具有最宽的共振吸收峰, 所得的纳米银粒子平均粒径最小. 环己烷形成的微乳液中反胶束具有特殊的界面强度, 导致纳米银晶核的形成速率过低, 纳米银晶粒的生长不完全.     

Silver halide colloid precursors for the synthesis of monolayer-protected clusters

A new method for the synthesis of monolayer-protected silver clusters (MPCs) based on the two-phase reduction of a stable negatively charged silver bromide sol is described. Phase transfer of the colloid to toluene is accomplished using tetra-n-octylammonium bromide as the phase transfer reagent. The advantage of this synthesis is to uncouple the formation of the silver halide colloid from its transfer and reduction in the organic phase, thus allowing control over each reaction step. The silver colloid in toluene was reduced with aqueous borohydride in the presence of 4-bromobenzenethiol as the passivating agent. The UV-visible absorption spectra indicate the intermediate formation of Ag(core)AgBr(shell) clusters during reduction. The resulting MPCs have been characterized by optical and transmission electron microscopy, energy-dispersive X-ray analysis, thermogravimetry, and UV-vis absorption spectroscopy. The formation of spiral cracks in the nanoparticulate agglomerates on solvent evaporation was observed. The spectra of thin films obtained by solvent evaporation have been analyzed using an effective medium theory.