表面荧光机制的理论研究

本文研究了 Rh B分子的 539.0 nm和 572 .5nm两荧光峰在表面增强活性银胶颗粒表面上的增强和淬灭效应 :在同一分子体系中同时观察到 530 .0 nm荧光峰的增强和 572 .5nm荧光峰的淬灭 ,并对其进行了理论计算。结果表明这两个荧光峰的增强或淬灭主要取决于局域电磁场增强和分子到金属表面无辐射能量转移衰减过程的竞争效应。当满足吸收共振增强和辐射共振增强时 ,荧光被增强 ;反之 ,荧光被淬灭。计算表明 ,荧光增强因子最高为 1     

染料分子荧光淬灭规律研究

本文研究了若丹明B、若丹明6G和吖啶橙三种染料分子吸附于银表面上时的荧光变化规律,发现在银胶颗粒表面的吸附均造成了其荧光强度急剧而大幅度的淬灭,淬灭随时间呈双曲线型衰减。同时利用这一实验结果对分子在表面间的吸附系数与脱附系数——这些表征分子与表面相互作用的重要参数——表达式进行了初步推导。     

染料分子荧光淬灭规律研究

本文研究了若丹明B、若丹明6G和吖啶橙三种染料分子吸附于银表面上时的荧光变化规律,发现在银胶颗粒表面的吸附均造成了其荧光强度急剧而大幅度的淬灭,淬灭随时间呈双曲线型衰减。同时利用这一实验结果对分子在表面间的吸附系数与脱附系数——这些表征分子与表面相互作用的重要参数——表达式进行了初步推导。     

若丹明B掺杂的SiO2凝胶的荧光光谱研究

以正硅酸乙酯（TEOS）和有机染料若丹明B（Rhodamine B)为原料，彩溶胶－凝胶方法（the sol-gel method)制备了若丹明B掺杂的SiO2凝胶，研究了SiO2凝胶的荧光光谱。报道了若丹明B在SiO2凝胶中的荧光光谱比在水中的荧光光谱发生红移，尤其在制备过程中的不同阶段，若丹明B掺杂SiO2凝胶的荧光光谱的峰位发生的一系列变化，从而得到了若丹明B在水中及若丹明B在SiO2凝胶制备过程之中，直至SiO2凝胶制备完毕的荧光光谱发生变化的全过程。还报道了在反应中的磁力搅抖阶段，采用回流过程和不采用回流过程两种方法时，对所得若丹明B掺杂SiO2凝胶的荧光光谱的影响。     

若丹明6G和若丹明B混合染料荧光谱特性及染料激光行为

实验发现若丹明6G和若丹明B混合溶液的荧光谱峰值波长随两种物质的混合比例不同而有规律地变化,与单一的若丹明6G和若丹明B相比,混合溶液的荧光谱线宽度明显增宽。使用混合染料,用改变混合比的方法对染料激光进行调谐,可简化调谐方法,调谐范围为557.4-588.5nm。     

溶剂对若丹明6G荧光寿命的影响(英文)

采用时间相关单光子计数技术测量了若丹明6G在不同溶剂中的荧光寿命.实验结果表明:在若丹明6G浓度为10~(-4)克分子/立升条件下,它的荧光寿命和溶质分子生成氢键的能力呈线性函数关系.据此,并参照溶剂对若丹明6G吸收光谱影响的实验结果,可以认为,溶剂对若丹明6G荧光寿命的影响主要是通过在溶质和溶剂分子间生成氢键,从而影响了若丹明6G分子发生缔合的容易程度所致.     

多道检测-激光诱导荧光光谱分析装置研究

采用Nd∶YAG激光器为激发光源,与CCD光学多道分析系统联用建立了多 道检测-激光诱导荧光光谱分析装置,并对该装置的设计进行了优化,荧光光谱测量范围35 0～1 000 nm,波长精度0.3 nm,探测器光谱响应灵敏度0.1 LX。采集和检测了若丹明6G乙 醇溶液的高信噪比荧光谱,最低检出限达到10-8 mol/L。线性范围为10-6～10-8 mol/L。将所建立的装置用于若丹明B荧光淬灭法测定水中硒的含量,获得了满意 的结果。方法的线性范围为1～10 μg/L,检出限为0.5 μg/L,加标回收率为81.3%～112.5 %。     

SiO2纳米颗粒对R6G-乙醇溶液荧光光谱影响

在3×10－4M和1×10－4M浓度的R6G-乙醇溶液中分别掺杂了8个不同浓度的SiO2纳米颗粒（107～1012 个/mL）.研究了SiO2纳米颗粒（100 nm）对若丹明6G（R6G）荧光光谱的影响,结果表明:n1～n4(1012～1010个/mL)浓度掺杂的SiO2纳米颗粒在549 nm处的有很好的荧光增强作用,对570 nm处的荧光峰有明显的粹灭作用|n5～n8(109~107个/mL)浓度掺杂的SiO2纳米颗粒在549 nm处没有明显的荧光增强作用,但对570 nm处的荧光峰有增强作用,荧光增强因子可达10%~20%.荧光增强与粹灭的原因在于纳米颗粒对荧光的散射作用和R6G无荧光H-型二聚体或荧光J-型二聚体的形成.     

纳米银粒子表面吸附染料分子的荧光增强及荧光猝灭现象

本文通过阴、阳离子型染料分子荧光素钠(FS)及若丹明6G(Rh6G)吸附在银胶体系内纳米银颗粒表面上,首次发现了FS的荧光增强谱及Rh6G的荧光猝灭谱.引起荧光增强及荧光猝灭的因素,除局域场和分子到金属表面能量转移这两个方面外,还与纳米银表面与被吸附分子之间的距离有关.     

甲基橙-银胶体系pH和氯离子效应的光谱研究

研究了甲基橙-银胶体系的光吸收和光致发光信号随pH值和加入氯离子的变化规律.实验发现随着pH值的增加, 分子的荧光发射峰与银胶的光吸收峰的重叠增大, 引起体系中能量转移效率的增加, 即428 nm分子荧光峰的淬灭和560 nm聚集体的特征光致发光峰增强现象的加剧.另外, 不同pH值下氯离子的加入都会使染料分子更加密集的吸附在胶体银颗粒表面, 形成分子吸附更加紧密的聚集体, 造成体系中受表面吸附分子影响的光致发光峰获得了极大的增强.同时, 因聚集体表面吸附层染料分子对入射光的大量吸收, 导致到达内核银表面的入射光强度减弱, 致使体系能量转移通道在一定程度上受阻, 表现为428 nm荧光峰的淬灭幅度减小.参照分子聚集体的形成理论, 接合体系光谱的变化, 从pH值的改变和Cl^-的加入对分子结构及加剧聚集体的形成等方面的影响来解释发光和光吸收的显著变化.     

The Fluorescence Enhancement of the Protein Adsorbed on the Surface of Ag Nanoparticle

The fluorescence enhancement of the BSA adsorbed on the surface of Ag nanoparticles is reported, where non-fluorescent collagen is used as the separator between the BSA and Ag nanoparticles. The study indicates that Ag nanoparticles can enhance the fluorescence of the BSA, especially the fluorescence of the tyrosine residues with lower quantum. Three types of Ag nanoparticles are evaluated including Ag island film, Ag colloids and fractal Ag electrode. Of them Ag island film is the best. The investigation suggests that the fluorescence enhancement of the BSA is related to the adsorption of the BSA on the surface of Ag island film through the hydrophobic interaction, while the collagen can promote the adsorption of the BSA on the surface of Ag island film and change its conformation, resulting in the interaction between BSA and Ag island film.     

pH-dependent fluorescence property of methyl red isomers in silver colloids

We report the use of silver (Ag) colloids in the spectroscopic differentiation of methyl red (MR) isomers (o-MR, m-MR, p-MR) by fluorescence techniques. Under different pH conditions, the formation of MR-Ag complex has an impact on the fluorescence band shapes and peak position shift, which are distinctive between MR isomers. The fluorescence quenching between 400 and 414 nm accompanied by simultaneous enhancement between 510 and 541 nm changes with pH are closely related to energy transfer efficiency and the interaction between the MR isomers and the Ag surface.     

2-氨基苯硫酚NIR-SERS光谱及其在纳米银表面吸附行为分析

本文采用静电自组装的方法制备了二维纳米银膜。UV-vis吸收光谱显示其等离子体共振吸收带位于400+900nm的光谱范围,延伸到了近红外区,可以较好的匹配785nm的近红外激发光源。以该纳米银膜为基底,对2-氨基苯硫酚(2-ATP)分子进行了近红外表面增强拉曼散射(NIR-SERS)检测,获得了重复性良好的NIR-SERS光谱图。实验表明:以2-ATP为探针分子时,该纳米银膜的NIR-SERS增强因子达到2.19×109。同时,本文采用密度泛函理论(DFT),以B3LYP/6-31G为基函数,对2-ATP分子进行结构优化和普通拉曼光谱(NR)计算,发现理论值和实验值吻合较好。此外,对2-ATP的NIR-SERS谱带进行了归属分析,发现当2-ATP分子在纳米银表面吸附时,是以-SH基团吸附到银表面,且同时-SH基团会被纳米银氧化。     

Surface‐enhanced Raman scattering studies of carbon nanotubes using Ag‐core Au‐shell nanoparticles

Surface‐enhanced Raman scattering from carbon nanotube bundles adsorbed with plasmon‐tunable Ag‐core Au‐shell nanoparticles (Ag@Au nps) was carried out for the first time. By utilizing nanoparticles whose plasmon resonance peak (541, 642 nm) closely matches the commonly used Raman excitation sources (532, 632.81 nm), we can observe a large enhancement in the Raman signatures of carbon nanotubes. We obtain greater enhancement in the Raman signal for the above case when compared to nanotubes adsorbed with conventional Ag, Au or other ‘off resonant’ Ag@Au nps. The power‐dependent SERS experiment on single‐walled nanotubes (SWNTs) with resonant Ag@Au nps reveals a linear behavior between the G‐band intensity and the photon flux density, which is in agreement with the vibrational pumping model of SERS. The observed enhancement by resonance matching is pronounced for carbon nanotubes and may lead to insights into understanding nanotube–nanoparticle interaction. Copyright © 2009 John Wiley & Sons, Ltd.     

Fluorescence Enhancement of a Polymer Planar Waveguide Doped with Rhodamine B and Ag Nanoparticles

Planar polymer multi-model waveguides doped with Ag nano-particles and rhodamine B are fabricated and investigated by the spectroscopy analysis method as well as the M-line method. Experimental results shown that fluorescence enhancement occurs when excited by a wide band wavelength with Ag nano-particle concentration at a certain level. The maximum enhancement factor in our experiment is obtained to be about 3.8 when excited by 350 nm. Our study may have potential applications in polymers optical elements, such as polymer waveguide lasers and amplifiers.     

A STUDY ON SURFACE-ENHANCED HYPER-RAMAN SCATTERING OF BASIC FUCHSIN ADSORBED ON THE SILVER COLLOID

This paper presents the surface-enhanced hyper-Raman scattering (SEHRS) effect of basic fuchsin (BF) adsorbed on the silver colloid. On the basis of the absorption spectra, a new absorption band at 1000nm has been observed in the case of BF adsorption on the silver colloid, The result indicates that surface electromagnetic enhancement also appears at the incident photon frequency in the near-IR region, which plays an important role in the SEHRS signals. The electromagnetic enhancement factor (2.0×l0⁴) is estimated by using electromagnetic model. Additionally, surface-enhanced second-harmonic generation (SHG) effect in the cases of pure silver colloid, silver colloid plus adsorbed molecule and KCl solution has been detected.     

多孔硅银淀积表面RhB染料分子的表面增强Raman散射

我们采用多孔硅和多孔硅银淀积表面作为衬底研究了ＲｈＢ染料分子的表面增强Ｒａ ｍａｎ散射。在多孔硅表面,ＲｈＢ染料分子的Ｒａｍａｎ散射有大约１０倍的表面增强效果;而在多孔硅的银淀积表面,表现出超过１０４表面增强。通过多孔硅表面银颗粒对ＲｈＢ染料分子荧光的抑制和对Ｒａｍａｎ散射的表面增强,我们获得了谱峰清晰的ＲｈＢ染料分子Ｒａｍａｎ散射谱