不同壳层厚度Au@SiO_2的表面增强拉曼效应

Surface Enhanced Raman Scattering of Au@SiO_2 Nanoparticles with Different Shell Thicknesses

通过电偶置换反应制备了尺寸在30~35 nm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Si O2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@SiO_2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@SiO_2复合粒子显著提高了拉曼信号的质量和检测的灵敏度,且Si O2壳层厚度对其SRES效应影响显著,壳层厚度为2 nm的复合粒子对R6G分子的检测极限可达10^(-7)mol/L。

Well-crystallized Au nanoparticles with average sizes of 30-35 nm were prepared through Galvanic replacement, and subsequently the Au@SiO2 composite particles with different silica shell thicknesses were 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（surface enhanced Raman scattering） effect of Au@SiO2 nanoparticles with various shell thicknesses. The results show that SERS signal intensity and quality of the R6 G 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 activity. The highest SERS effect is obtained when using Au@SiO2 nanoparticles with shell thickness of 2 nm with an extremely low detection limit of 10^-7 mol/L.