Novel Surface Enhanced Raman Scattering Substrates:Preparation And Application

Surface enhanced Raman scattering（SERS）technology is based on the principle of Raman scattering which highly increases the signal intensity by using metal materials with rough surface as substrates.One of the most important factors of this technology is the preparation of SERS substrates.In this work,two kinds of novel SERS substrates were developed.On one hand,to overcome the disadvantages of current SERS substrates,such as high equipment requirements,complex steps and high cost,we developed a new method to prepare Copper foil-gold nanoparticles（CuF-AuNPs）SERS substrate through in-situ reduction AuNPs on copper foil.On the other hand,based on the recent research of photonic crystal（PC）materials in the field of optical detection,we developed a novel surface enhanced Raman scattering substrate（PC-AuNPs）through combining the band edge effect of photonic crystal and SERS technology.Detailed information is described as follows:（1）CuF-AuNPs SERS substrate was fabricated by in-situ reduction AuNPs on the rough surface of copper foil treated by nitric acid.The effect of nitric acid concentration on the surface roughness of copper foil and the effect of HAuCl₄reduction time on the merits of the CuF-AuNPs substrate were investigated.The Raman scattering signal of different concentrations from 1×10^-88 mol/L to 1×10^-3mol/L of Rhodamine B（RHb）was detected on CuF-AuNPs.A good linearity（y=1492x+12435,R²=0.995）relationship was obtained between the characteristic peak intensity of RHb and its logarithmic concentration.The detection limit reached1×10^-88 mol/L.（2）Band edge effect of photonic crystal（PC）was combined with gold nanoparticles（AuNPs）to fabricate a novel surface enhanced Raman scattering substrate（PC-AuNPs）.The preparation of PC-AuNPs substrate consisted of three steps.Firstly,SiO₂ nanospheres were amino-modified.Then,an opal PC structure was obtained by vertical deposition of SiO₂ nanospheres.Finally,AuNPs were loaded on the surface of opal structure.The Raman scattering signal of Rhodamine B（RHb）was detected on PC-AuNPs to evaluate the merits of this new substrate.It was found that the band gap range of photonic crystal and the loading amount of AuNPs are important factors for PC-AuNPs.A good linearity（y=1711x+15244,R²=0.9994）relationship can be obtained between the characteristic peak intensity of RHb and its logarithmic concentration.The detection limit reached 1×10^-88 mol/L.This method is simple and exhibits good sensitivity and reproducibility for qualitative and quantitative detection,and could provide a novel strategy for the development of SERS substrate.