【作者】 张波；

【导师】 赵爱武；

【作者基本信息】 中国科学技术大学 ， 无机化学， 2010， 硕士

【摘要】 最近几十年,银纳米粒子由于其独特地物理和化学性质,已经成为许多基础研究与应用研究所关注的对象。由于在一定频率的外界电磁场作用下银内部的自由电子做规则运动而产生的表面等离子体共振,使得银纳米粒子四周的电磁场被极大地增强。基于这一现象,表面增强拉曼散射(SERS)光谱技术应运而生,最近的研究更是成功地将SERS光谱技术应用到单分子检测中。而银纳米材料的性质与材料的形状、尺寸、结构等因素息息相关。所以,对银纳米材料形貌可控制备的研究就显得非常地重要。本论文主要研究不同形貌银纳米材料的可控制备以及其SERS性质,主要研究内容分为以下三个部分:(1)水溶液法是进行无机化学合成的最常用方法,通过添加柠檬酸钠,用弱还原剂抗坏血酸还原硝酸银水溶液成功地制备出具有花状结构的银微纳米材料。通过研究产物的形貌、结构、以及反映中间产物的形貌,提出其生长机理。研究了柠檬酸钠在花状银的形成过程中起到的作用以及pH值对产物的形貌的影响。把产物沉积在硅片上作为SERS基底能够检测到10-8 M的罗丹明6G(R6G)分子,增强因子达到4.1×107。(2)为了模拟矿物的形成条件,发明了水热法,在水热法的基础上,把溶剂由水变为有机溶剂就是一种新的化学合成方法:溶剂热法。在无机控制合成中,聚乙烯吡咯烷酮(PVP)是被经常用到的有机物。在实验中PVP既起到稳定纳米颗粒的作用,又起着帽化试剂(capping agent)的作用。讨论了盐酸在立方体银纳米粒子的形成中起到重要的作用,当不加盐酸时,或者用硫酸代替盐酸时,均不能得到立方体银纳米粒子。以R6G为目标分子检测了立方银纳米粒子作为SERS基底增强能力。(3)多孔氧化铝薄膜是很好的制备纳米材料的模板,在总结前人经验的基础上,采用优化的二次阳极氧化法制备出具有整齐六方结构的多孔氧化铝薄膜。以多孔氧化铝为模板,用交流电沉积的方法制备出排列整齐的银微纳米线阵列。研究了银纳米线阵列作为SERS基底检测对巯基苯甲酸(PMBA)时的SERS性能。更多还原

【Abstract】 In the past decades, silver nanoparticles have been the subjects of a numbers of fundamental and practical studies, due to its specially physical and chemical properties. Under irradiation of lights with a proper frequency, the surface plasmon in silver particles can be excited, as a result, the local electromagnetic field close to the particles can be greatly enhanced. This is the foundation of Surface-enhanced Raman scattering (SERS) spectroscopy techniques that sensitive to the electromagnetic fields. Recently, SERS techniques have been used to detect the signs of single molecule. The SERS properties of silver nanoparticles are strongly dependent on the shape, size, and structure of the particles. In this dissertation, controlled synthesis of silver nanoparticles and SERS properties are the main content was studied, the three main parties are following:(1) Aqua-solution method is one of the most common method of inorganic chemical synthesis. Flower-like silver micro-nano materials were successfully prepared by ascorbic acid reduces silver nitrate in aqueous solution with the aid of sodium citrate. By studying the morphology and surface structure of the products, and the morphology of intermediate products, its growth mechanism was proposed. The effects of sodium citrate and pH value on the flower-like silver micro-nano materials were studied. The products deposited on silicon were used as SERS substrates to detect 10-8 M Rhodamine 6G (R6G) molecules, and the enhancement factor reached 4.1×107.(2) In order to simulate the conditions of mineral formation, the hydrothermal method was invented. When using organic solvents instead of water, a new chemical synthesis method: solvothermal was invented. In the inorganic controlled synthesis, polyvinylpyrrolidone (PVP) are frequently used organic agent. In the experiments, PVP not only plays the role of stable nanoparticles, but also plays the role of capping agent. Hydrochloric acid plays an important role in the formation of the cube silver nanoparticles, as without HCl or sulfuric acid instead of hydrochloric acid, cannot obtained the cube silver nanoparticles. We evaluated the SERS properties of the cube silver nanoparticles dispersed on Si wafer using Rhodamine 6G (R6G) as target molecule.(3) porous alumina film is a good template for preparation of nanomaterials, on the basis of previous experience, 6-fold rotational symmetric porous anodic aluminum oxide film was prepared by the optimized anodic oxidation. Use porous anodic aluminum oxide film as template, silver nanowires array was prepared by the method of the alternating current deposition. We evaluated the SERS properties of the silver nanowires array using R6G as target molecule.更多还原