光诱导转化法制备片状三角形银纳米粒子的表面增强喇曼散射

SERS Study of Triangular Silver Nanoplates Prepared by Photoinduced Conversion Method

采用柠檬酸三钠化学还原法制备球形Ag纳米粒子溶胶,并用高压球形氙灯对球形Ag纳米粒子溶胶进行光诱导实验.利用透射电子显微镜、紫外-可见吸收光谱研究了不同光照时间下的银胶纳米粒子的光谱特性和表面形貌,并以结晶紫为探针分子测量了银胶纳米粒子的表面增强喇曼散射光谱.实验结果表明:随着光照时间的增多,Ag纳米粒子溶胶颜色变化显著;紫外-可见吸收光谱吸收峰从单一峰渐渐显示出多个峰;透射电子显微镜图显示Ag纳米粒子由球形逐渐转变成片状三角形银纳米粒子、截角的片状三角形银纳米粒子;表面增强喇曼散射的增强效应随着光照时间的变化先逐渐增大,然后逐渐减小.

Spherical silver nanoparticles are prepared by chemical reduction of sodium citrate,and photoinduced conversion of spherical Ag nanoparticles is conducted by the irradiation of high pressure spherical Xe lamp.The spectra property and morphologies of silver nanoparticles prepared under different irradiation time are studied by UV-visible absorption spectroscopy and Transmission Electron Microscope（TEM）.Using crystal violet as a molecular probe,SERS spectra of crystal violet on Ag nanoparticles are studied.Experimental results indicate that the color of Ag colloid changes observably and the number of absorption peak of Ag colloid gradually manifold with the increase of irradiation time.TEM pictures show that morphology of Ag nanoparticles is evolved from sphericity to triangular plate,finally truncated triangular plate.As the irradiation time increasing,the SERS signal intensity increases first,and then decreases.