先采用一步法制备碳纳米管和银纳米颗粒(CNTs/Ag1)基底,再采用银纳米溶胶(Ag2)修饰CNTs/Ag1,得到CNTs/Ag1/Ag2复合结构基底。利用三维时域有限差分(3D-FDTD)计算了电场分布和增强因子。拉曼测试实验结果表明:对罗丹明6G(R6G)的检测极限低至10 -15 mol/L;采用归一化比率k实现对低浓度(10 -15~10 -10 mol/L)的R6G的定量检测,k的相对标准偏差(RSD)低至拉曼强度的RSD的一半。此外,实现了对浓度为10 -9~10 -6 mol/L的结晶紫(CV)溶液的定量检测。不同浓度的两种探针分子的k值的线性拟合度均达到99%以上。

Herein, the substrate comprising carbon nanotubes and silver nanoparticles (CNTs/Ag₁) was first prepared using the one-step method, and then CNTs/Ag₁ was decorated by the additional Ag nanoparticle sol (Ag₂) to constitute the final composite structural substrate (CNTs/Ag₁/Ag₂). The corresponding electric field distributions and the enhancement factors were calculated using the three-dimensional finite difference time domain (3D-FDTD) algorithm. Experimental results of Raman test show that the detection limit is 10 ^-15 mol/L for rhodamine 6G (R6G). Quantitative detection of R6G with a low-concentration of 10 ^-15-10 ^-10 mol/L is realized using the normalized ratio k. The relative standard deviation (RSD) value of k is as low as half of the RSD of Raman intensity. Moreover, quantitative detection of crystal violet (CV) solution with a concentration of 10 ^-9-10 ^-6 mol/L is achieved. The linearity-fitting degrees of all k values of two probe molecules are larger than 99% at different concentrations.