银纳米棱镜的形成及其光学性能研究

Formation of Silver Nanoprisms and Their Optical Properties

以有机溶剂作为反应介质 ,聚合物为稳定剂 ,通过微波辅助溶液法成功地制备了具有特殊光学性能的银纳米棱镜 .利用 X射线衍射、透射电子显微镜和紫外 -可见光谱等手段跟踪反应过程 .结果显示 ,随着反应的进行 ,银纳米粒子由 1 0 nm左右的球形颗粒逐渐转变为具有规则三角形 (或缺角的三角形 )形貌的纳米棱镜 ;同时 ,紫外 -可见吸收峰不但显示出明显的量子尺寸效应 ,而且吸收峰也由单一的等离子共振吸收峰变为多重的多极吸收峰共同存在 ,胶体溶液也随之显示出不同的颜色 .改变反应物的配比、体系的浓度及无机前驱物都会得到位置和峰形各不相同的吸收曲线 ,从而得到多彩的纳米银胶体溶液 .

Silver nanoprisms have been prepared by a soft solution approach under microwave irradiation from the solution of silver nitrate(AgNO 3) in the presence of poly(N-vinyl-2-pyrrolidone) without any other reducing agent. The reaction process was followed by X-ray powder diffraction, TEM and UV-Vis spectroscopy. The results showed that silver nanoprisms were formed from the spherical nanoparticles. Most of them were triangular(edge length 50-100 nm) or truncated triangular nanoprisms and two distinct quadrupole plasmon resonances in UV-Vis spectra were observed. With reaction progress, the colloid solution with a interesting color was obtained. The influences of the PVP/AgNO 3 mass ratio, solid content and inorganic precursor on the optical properties and morphology of silver nanoparticles were investigated.