Surface Enhanced Raman Spectra Film Basement Of The Building And Its Application Research

Surface enhanced Raman scattering(SERS) spectroscopy has a wide attentionand application in the filed of analytical chemistry and surface chemistry because ofits ultra sensitivity. Thus, preparation of good SERS substrate is one of the key points.Metal electrode and metal colloid are two common SERS substrates which have bothadvantages and disadvantages. Metal electrode has a strong SERS effect, but it need acomplicated pre-procedure including polish and roughen; whereas metal colloid thatis easy prepared, is difficult to control the same preparation environment every time.What’s more, it will be unstable after the addition of the analyte. The aggregation ofmetal colloid trends to coagulate. There are various kinds of methods to prepare metalfilm such as template, self-assemble, electrochemistry, lithography, ion sputtering,laser deposition etc. Among these methods, some are used with expensive instruments;some are simple and facile, like self-assemble and electrochemistry. In this paper, weprepared three different metal film SERS substrates by the method of self-assemble orelectrochemistry.(1) The growth of uniform gold nanoparticles on the ITO surface in the presenceof phytic acid. Phytic acid, a green organic from cereals, is no poison, no pollutionand low price. It is used to be food additives and metal ion chelating agent. In thiswork, the gold nanoparticles are prepared by phytic acid on the ITO surface withseeding. First, phytic acid is bridge-agent attached ITO surface to form uniformsurface. Second, phytic acid is reductant to make HAuCl4to Au. From thecharacterization of SERS, we get the optimum growth time and temperature. Thesubstrate has a good SERS signal to different molecules. The RSD is about2.8%andafter the storage of2months the peak intensity is still80%compared to that freshprepared. It owns uniform, stability, universality.(2) Preparation of flowerlike Au@R6G nanoparticles with high SERS effect bycyclic voltammetry. Electrochemistry is a simple, facile and controllable method. Inthis work, we employ electrochemical deposition in HAuCl4containing probemolecules R6G to prepare Au@R6G nanoparticles. It is more convenient to the procedure that metal substrate are first prepared, then probe molecules are adsorbedon them to evaluate the SERS effect because of the one step preparation instead oftwo steps. From the SERS characterization, the SERS effect is one-folder higher thanAu@R6G SERS active substrates normally prepared in presenting literatures. LOD ofthis improved SERS substrate based on this strategy can reach10-10M for the R6G. Itowns the good stability, uniform and reproducibility.(3) Preparation of Ag@Au composite film derived from DVD and its SERSapplication. There is a silver and gold reflection layer in DVD, which shapescorrugated morphology. Cluster array Ag@Au film is formed by electrochemistry toroughen the silver and gold reflection layer. From the SERS characterization, it is anexcellent substrate that can improve the SERS signal of various molecules. The RSDis about7%. There are several merits of the one-way DVD SERS substrate such aslow price of the raw material, easy preparation and large production.