不同壳层厚度Au@SiO2的表面增强拉曼效应

Au@SiO2 Nanoparticle with Different Shell Thickness for Surface Enhanced Raman Scattering

摘要:

本文通过电偶置换反应制备了尺寸在30~35nm的结晶性良好的Au纳米颗粒，并成功在其表面包覆了不同厚度的SiO2壳层，利用TEM、HRTEM和UV-Vis对样品的结构和形貌进行了表征，并以罗丹明6G（R6G）为探针分子，对Au@SiO2复合粒子的表面增强拉曼散射(SERS)效应进行了研究。结果显示，相对于Au纳米颗粒，Au@SiO2复合粒子显著提高了拉曼信号的质量和检测的灵敏度，且SiO2壳层厚度对其SRES效应影响显著，壳层厚度为2nm的复合粒子对R6G分子的检测极限可达10-7mol/L。

Abstract:

In this work, well-crystallized Au nanoparticles with avarage sizes of 30 ~35 nm were obtained through Galvanic replacement, and subsequently the Au@SiO2 composite particles with different silica shell thicknesses were successfully synthesized. The microstructures and morphologies of the Au@SiO2 nanoparticles were also characterized using UV-Vis, TEM and HRTEM. The Rhodamine 6G (R6G) dye was selected as probe molecules to evaluate the SERS effects of Au@SiO2 nanoparticles with various shell thicknesses. The results show that SRES signal intensity and quality of the R6G molecules are obviously improved as compared with Au NPs synthesized using the same method. Furthermore, the SiO2 shell thickness has a significant influence on the SERS acitivity. The highest SERS effect is abtained using Au@SiO2 nanoparticles with shell thickness of 2nm with an extremely low detection limit of 10-7 mol/L.