金多孔纳米片的一锅法制备及其在SERS检测中的应用

设计并构建多样的金微纳米结构是实现表面增强拉曼光谱（SERS）信号放大的合理途径。利用氯金酸与聚乙二醇（PEG）的氧化还原反应,通过水热合成法制备出金多孔纳米片。PEG在制备过程中既是包裹剂又是还原剂。该制备方法反应温度比较温和,采用一锅法一步合成工艺,成本效益高且环境友好。所制备的金多孔片尺寸多为微米级,清洗后表面没有有机物污染。EDS分析进一步证实所制备的多孔片结构为金单质。结果表明,金多孔纳米片的形貌可通过反应时间、PEG浓度和金离子浓度等实验参数进行调整。金多孔纳米片制备的拉曼光谱基底具有优异的SERS光谱增强效果,并在检测中表现出良好的重现性。另外,所制备的金纳米多孔片基底实现了有机农药福美双和甲拌磷的快速灵敏分析检测。     

玻璃基底上纳米银粒子的原位生长及其表面增强拉曼散射活性

利用预处理-化学沉积法在玻璃基底表面原位生长形貌各异的纳米银粒子,获得高活性的表面增强拉曼散射(SERS)基底。采用SEM、XRD和UV等测试手段对样品进行分析和表征,并考察纳米银粒子的形貌对其薄膜基底表面增强拉曼散射活性的影响。结果表明:随着反应液中硝酸银与乙二胺的摩尔比以及反应温度的改变,纳米银粒子的形貌发生变化。当反应温度为30℃、硝酸银与乙二胺的摩尔比为1:5时,制备出的由纳米银薄片组成的薄膜具有最强的紫外吸收光谱红移,可红移至800 nm;并且以此条件得到的表面增强拉曼散射活性基底具有最强的表面增强拉曼散射信号,拉曼增强因子达到258.4。     

银纳米线蚀刻及其表面等离激元特性

采用电子扫描显微镜(SEM)表征过氧化氢(H_2O_2)蚀刻的银纳米线表面形貌,采用紫外-可见(UV-vis)吸收光谱、荧光光谱以及拉曼光谱研究蚀刻后银纳米线的表面等离激元特性。结果表明:H_2O_2可有效蚀刻银纳米线表面形貌,与未蚀刻的银纳米线相比,蚀刻后的银纳米线平均直径减小,表面形成纳米凹槽以及立方状的银纳米粒子,银纳米线表面等离激元共振吸收峰强度增大,并呈现宽化。由于蚀刻后的银纳米线光电耦合增强,导致表面的电磁场强度增大,对罗丹明B(RB)探针分子的荧光辐射增强16.8倍,对RB探针分子的拉曼散射信号增强约6.2×105倍。这对于纳米金属表面增强光谱具有积极的应用意义。     

球形SiO2表面Ag纳米粒子生长及其拉曼增强效应

以聚乙烯吡咯烷酮(PVP)作为还原剂和稳定剂制备SiO2/Ag纳米复合材料,分析银氨络离子的浓度对银纳米粒子的影响,采用透射电镜(TEM)、扫描电镜(SEM)对SiO2/Ag复合材料进行表征,并研究以SiO2/Ag为基底的表面拉曼散射增强。结果表明,银纳米颗粒以多晶形式沉积在球形二氧化硅表面,通过调节银氨络离子的浓度可以改变Ag纳米颗粒的大小及其在SiO2上的沉积量;当银的沉积量增加时,表面拉曼散射也随之增强。     

陈化胶体金的简便合成与光谱特性（英文）

描述了通过只添加氢氧化钠到氯金酸和十六烷基三甲基溴化铵混合液中合成陈化纳米金胶体,并研究了该胶体的光谱特性。基于傅里叶红外光谱对纳米金的形成机理进行了分析并以紫外可见光谱和扫描电子显微镜表征了添加不同量的氢氧化钠而获得的陈化3 m的胶体金。同时获得了吸附于陈化了3 m的胶体金表面上的亚甲基蓝的表面增强拉曼光谱。结果表明,陈化3 m的胶体金其紫外可见光谱具有宽的等离子吸收峰,对这种宽化改变进行了解释分析。其透射电子显微镜分析表明在纳米金合成阶段,添加不同量的氢氧化钠可影响纳米金大小,同时不同量的氢氧化钠影响着胶体金的陈化过程并产生出形状依赖的陈化胶体金。表面增强拉曼光谱的增强特性不同证明了所形成的陈化胶体金的大小/形状依赖特征。因此,我们期望着这种陈化胶体金能够在生化分析领域被得到开发应用。     

陈化胶体金的简便合成与光谱特性

文章描述了通过只添加氢氧化钠到氯金酸和十六烷基三甲基溴化铵混合液中合成陈化纳米金胶体,并研究了该胶体的光谱特性。基于傅里叶红外光谱对纳米金的形成机理进行了分析并以紫外可见光谱和扫描电子显微镜表征了添加不同量的氢氧化钠而获得的陈化三个月的胶体金。同时文章获得了吸附于陈化了三个月的胶体金表面上的亚甲基蓝的表面增强拉曼光谱。结果表明,陈化三个月的胶体金其紫外可见光谱具有宽的等离子吸收峰,这种宽化改变在文章对中进行了解释分析。其透射电子显微镜图片表明了在纳米金合成阶段,添加不同量的氢氧化钠可影响纳米金大小,同时不同量的氢氧化钠影响着胶体金的陈化过程并产生出形状依赖的陈化胶体金。表面增强拉曼光谱的增强特性不同证明了所形成的陈化胶体金的大小/形状依赖特征。因此,我们期望着这种陈化胶体金能够在生化分析领域被得到开发应用。     

倾斜生长法制备表面增强拉曼散射基底及其应用

基于贵金属纳米结构表面增强拉曼散射可实现物质的痕量检测。主要介绍了基于倾斜生长法对Ag纳米棒阵列的可控制备,及其应用于痕量物质的检测,并通过主成分分析法和偏最小二乘回归法建立了痕量物质的半定量和定量分析。     

微波辅助法制备纳米银胶及其在拉曼表面增强方面的应用

采用一步微波辅助法制备了纳米银胶,并利用紫外-可见吸收光谱,透射电子显微镜(TEM)和原子力显微镜(AFM)等检测手段对纳米银胶相应的性质和结构进行了表征。利用罗丹明6G(R6G)为探针分子,考察了不同反应时间制备的纳米银胶对拉曼散射(SERS)的表面增强效果。结果表明,纳米银胶可以提高拉曼散射的信号强度,比较和分析了增强后的拉曼光谱。同时,我们对纳米银胶增强拉曼散射信号的机理进行了详细的研究。     

表面增强拉曼光谱在工业水处理及金属材料保护中的应用

表面增强拉曼光谱SERS广泛地用于各种物质在金、银、铜等贵金属表面的吸附机理研究 ,而实际应用中更需要的是铁铝等金属 ,尤其是含铁材料的SERS研究。很多含硫化合物是工业水处理和材料保护中铁的良好缓蚀剂。本工作尝试用表面增强拉曼光谱研究了苄基双硫化合物在铁表面的吸附状态 ,获得了很好的增强效应 ,为拓展拉曼光谱的应用提供了一个很好的途径。     

微波辅助法制备纳米银胶及其在拉曼表面增强方面的应用（英文）

采用一步微波辅助法制备了纳米银胶,并利用紫外-可见吸收光谱,透射电子显微镜(TEM)和原子力显微镜(AFM)等检测手段对纳米银胶相应的性质和结构进行了表征。利用罗丹明6G(R6G)为探针分子,考察了不同反应时间制备的纳米银胶对拉曼散射(SERS)的表面增强效果。结果表明,纳米银胶可以提高拉曼散射的信号强度,比较和分析了增强后的拉曼光谱。同时,对纳米银胶增强拉曼散射信号的机理进行了详细的研究。     

Raman scattering investigation of Bi2Te3 hexagonal nanoplates prepared by a solvothermal process in the absence of NaOH

Hexagonal Bi₂Te₃ nanoplates were synthesized by a simple solvothermal process in the absence of NaOH. The composition, morphology and size of the as-prepared products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Raman scattering optical properties of the as-prepared Bi₂Te₃ nanoplates were investigated by micro-Raman spectroscopy. The Raman spectrum shows that infrared (IR) active mode (A_1u), which must be odd parity and is Raman forbidden for bulk crystal due to its inversion symmetry, is greatly activated and shown up clearly in Raman scattering spectrum. We attribute the appearance of infrared active (A_1u) in Raman spectrum to crystal symmetry breaking of Bi₂Te₃ hexagonal nanoplates. The as-grown Bi₂Te₃ hexagonal nanoplates, exhibiting novel Raman optical properties compared with bulk crystals, may find potential applications in thermoelectric devices.     

石英毛细管内壁镀金工艺的研究

目的开发出切实可行的石英毛细管内壁镀金工艺,应用于激光拉曼的气体分析检测中。方法先用石英玻璃片进行镀金工艺研究,经过对羟基化、硅烷化、纳米金颗粒修饰、湿法镀金各步条件参数的确定,获得最佳的镀金工艺方案,再对相关参数进行调整,应用于石英毛细管。将镀金石英毛细管应用于激光拉曼的气体分析测试中,分析其对散射信号的增强效果。结果 Na OH的浓度和毛细管内溶液的流速及时间显著影响纳米金颗粒的吸附沉积。最佳的石英毛细管内壁镀金工艺为:5 mol/L Na OH处理1min→APTMS/IPA烷基化修饰→金溶胶在流速0.8 m L/min下处理4 h→含盐酸羟胺的镀金液在流速0.8m L/min下处理4 h。该工艺制得的内壁镀金毛细管用于气体拉曼测试后,可将空气中N2相对峰值从148 counts(未镀金毛细管)提高至480 counts。结论制备出的镀金石英毛细管可增强激光拉曼检测气体的信号,为进一步实现气体在线拉曼监测奠定基础。     

Ultra-sensitive detection of individual gold nanoparticles: spectroscopy and applications to biology

Gold nanoparticles are now widely used in different fields of chemistry, physics and biology. For many applications, it became crucial to use the smallest ones and at the same time to be able to detect them at the single particle level with versatile optical methods. Such methods should also allow the study of their intimate optical properties. Here we review the ultra-sensitive optical methods based on the photothermal effect which permit the detection of individual gold nanoparticles down to 1.4 nm through their absorption. The absorption spectroscopy of the Surface Plasmon Resonance of individual gold nanoparticles down to 5nm is further presented and revealed intrinsic size effects in the optical response of the smallest nanoparticles. Different applications to biology are also presented such as for new types of gold nanoparticles based DNA microarrays and for live cell molecular imaging owing to the insensitivity of the photothermal methods to scattering environments.     

Surface chemical modification of CVD diamond films by laser irradiation

The wettability of CVD diamonds, which much depends on the surface chemical state, is of great importance to their applications. In this work, surface chemical modification of diamond films are performed with nanosecond (ns) laser irradiation in ambient air, and the influence of chemical modification on the wettability of diamond films is investigated. Two types of laser fluence, namely fluence above ablation threshold and fluence between ablation threshold and graphitization threshold are used. The surface morphology and chemical composition of irradiated diamond films are characterized by scanning electron microscope (SEM), X-ray diffraction spectroscopy (XRD), Raman scattering analysis and X-ray photoelectron spectroscopy (XPS), respectively. Graphitization, oxidation and nitridation on CVD diamond surface can be clearly observed for both fluences. Angle contact measurements show that after such evolution of surface terminations super-hydrophilic properties can be obtained. Besides, the fluence between ablation threshold and graphitization threshold appears to be more preferable, for the surface graphitization with such fluence is much slighter in comparison with the fluence above ablation threshold. This is of great importance to the bioimplantable application of CVD diamond films.     

Optical and acoustic phonon modes confined in gallium phosphide nanoparticles

The main aim of this paper is to discuss the confinement effects on the optical and acoustic phonon vibrational modes in gallium phosphide(GaP) nanoparticles(cylindric grain).The Raman scattering from the GaP nanoparticles was investigated.It was found that the red-shifts of the longitudinal optical(LO) mode and transverse optical(TO) mode were 15 cm?1 and 13.8 cm?1,respectively.It is generally accepted that the red-shifts of the optical phonon modes are due to the presence of smaller nanosized particles(～1.2 nm) acting as the nanoclustered building blocks of the GaP nanoparticles.In the low frequency Raman spectrum,a set of Stokes lines with almost the same spacing was clearly observed.The scattering feature originates from the discrete phonon density of states of the nanoclustered building blocks.According to Lamb's vibrational theory,the Raman shift wavenumbers of the spheroidal mode and torsional mode of the lowest energy surface modes for the nanoclustered building blocks were calculated.Good agreement can be achieved between the calculated results and the observed scattering peaks.These results indicate that the corresponding Raman peaks are due to scattering from the localized acoustic phonons in the nanoclustered building blocks in the GaP nanoparticles.     

Silver-coated silicon nano-particles prepared by thermal decomposition

The silver-coated silicon nano-particles were prepared by thermal decomposition, assisted with post-treatments of electrochemical polishing. Structure and morphology identification indicated the differences between Ag-coated p-type and n-type porous silicon layers were due to their different porosity, and the higher porosity of p-type porous silicon layers was suitable to form the cubic silver particles with nm size. The post-process was used to remove the excess Ag and Ag–O continents from the surface, and the processes were monitored by electric measurement and Raman scattering spectroscopy. The overall change in resistance and Raman spectra revealed the formation of silver-coated silicon nano-particles for p-type porous silicon layer.     

Hydrothermal synthesis of silver nanoparticles by sodium alginate and their applications in surface-enhanced Raman scattering and catalysis

Various methods have been reported for the synthesis of Ag nanoparticles (NPs) by reduction of AgNO₃ with a chemical reducing agent. However, many of them pose potential environmental and biological risks. Herein, we demonstrate for the first time that Ag NPs can be synthesized using sodium alginate (NaAlg) as both reducing and stabilizing agents by a simple and effective green hydrothermal strategy. By controlling the temperature and time of reaction, Ag nanospheres and nanoplates can be fabricated. Moreover, the application of an Ag NPs–NaAlg thin film in surface-enhanced Raman scattering of rhodamine 6G is demonstrated. The catalytic efficiency of the as-prepared Ag NPs embedded in calcium alginate beads is evaluated for reaction of 4-nitrophenol reduction to 4-aminophenol in the presence of NaBH₄.