【作者】 吴青松；

【导师】 张彩碚； 赵岩；

【作者基本信息】 东北大学 ， 材料物理与化学， 2006， 博士

【摘要】 金、银纳米颗粒及其纳米壳层在电学、光学、表面催化和传感等领域表现出优异的物理和化学特性，可作为介电材料、电极材料、光学标签、光敏感材料、生物传感器以及拉曼增强基底等，有着广泛的应用前景。本论文采用液相化学还原法和表面种子诱导法，分别制备出三角形银、三角形金纳米片和纺锤形银、金和金银双金属纳米壳层，借助于透射电镜(TEM)、扫描电镜(SEM)、X射线衍射(XRD)、紫外可见吸收光谱(UV-Vis)、拉曼光谱(RS)等现代测试技术对金银纳米颗粒及其纳米壳层的尺度、形状、结构特点、光学特性及其形成机理进行了较为系统的研究。 在非光参与的条件下，硝酸银被强弱两种还原剂(硼氢化钠和柠檬酸钠)分步还原，硼氢化钠还原产生的少量小尺寸(≤10nm)初级球形银纳米颗粒在表面活性剂聚氧乙烯十二烷基醚(BRIJ35)分子的诱导作用下，随着硝酸银被柠檬酸钠进一步还原，在不同反应温度下经不同生长方式转变形成三角形银纳米片。在80℃条件下，先形成小尺寸的形似三角形的银纳米颗粒，后直接长大形成三角形银纳米片；在40℃和60℃条件下，初级银纳米颗粒先聚集成线，形成三角形银纳米框架，后经填补不断密实，长大形成三角形银纳米片。三角形银纳米片的边长尺寸随着反应温度的降低、BRIJ35分子或硼氢化钠有效浓度的降低而增大，其三角形貌的完整性随着BRIJ35的浓度的偏低或偏高以及硼氢化钠浓度的升高而降低，同时对溶液的PH值非常敏感。在紫外可见吸收光谱中，三角形银纳米片具有三个特征吸收峰，分别对应其面外四极、面内四极和面内双极共振吸收，其中面内双极共振吸收峰随着三角形银纳米片边长尺寸的增大而不断红移，最大可红移到800nm以外更长波区。 三角形银纳米片在有机分子十六烷基三甲基溴化铵(CTAB)中溴离子和有机基团的作用下，形貌发生重塑。三角形银纳米片在高浓度CTAB分子的作用下经历截角三角形、椭圆形的变形，最后转变形成圆片形银纳米颗粒；在中等浓度CTAB分子的作用下，转变形成纺锤形银纳米片；在较低浓度CTAB分子的作用下，转变形成棒状为主的银纳米颗粒。随着银纳米颗粒形貌的变化，其光吸收性能也相应改变。 80℃～40℃三种温度条件下经不同生长方式形成的三角形银纳米片，自组织行更多还原

【Abstract】 Gold/silver nanoparticles and nanoshells exhibited unique physicochemical properties in electrics, optics, catalyzer and sensor, making them potential candidates for a wide variety of applications, such as dielectric materials, electrodes, optical labels, light-sensitive materials, biosensors and surface-enhanced Raman scattering (SERS) substrates. This dissertation reported the preparation of triangular silver, trangular gold nanoplates, spindle silver, gold and gold-silver bimetallic nanoshells by using a solution -reduction method and a seed-mediated surface growing technique, respectively. By means of characterization methods with transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Ultraviolet-Visible (UV-Vis) spectroscopy and laser Raman spectroscopy (LRS), the sizes, morphologies, structures, formation mechanism and related optical properties of these metal nanoparticles and nanoshells were investigated.A new non-light chemical method was reported to prepare triangular silver nanoplates. In the presence of polyoxyethylene (23) lauryl ether (BRIJ35) molecules, nitrate silver was reduced by sodium borohydride and sodium citrate, and the produced spherical silver nanoparticles transformed into triangular nanoplates by two growth modes at different reaction temperatures. When the solution was heated at 80℃, small triangle-like silver nanoparticles formed and then grew up into the triangular nanoplates directly. However, when the solution was heated at 60℃, small spherical silver nanparticles lined up with each other to form triangular nanoframes, and then transformed into the triangular nanoplates by filling with small silver cystals into their inners. The border size of the triangular silver nanoplates increased with the decreases in reaction temperature and effective concentration of the BRIJ35 molecules or sodium borohydride. The completeness of their triangular shape decreased as the low concentration of BRIJ35 molecules became too high or too, and the concentration of sodium borohydride increased, and meanwhile it was sensitive to the PH values of the reactive solution. The triangular silver nanoplates had three characteristic absorption更多还原