| Summary: | 碩士 === 逢甲大學 === 光電研究所 === 95 === This thesis deals with the surface enhanced Raman scattering (SERS) of benzoic acid’s ring breathing mode(1003cm-1) and carboxyl C=O vibrational mode (1600cm-1 ) by the silver particles doped sol-gels. The sol-gels are made out of tetramethyl-orthosilicat(TMOS), water, methanol, and formamide with the molar ratio of 1:4:4:2. Methanol is chosen as the solvent of the benzoic acid (BA) solutions for its immunity to the SERS’s effect. Consequently, methanol’s 1033cm-1 peak can served as a good internal reference for the normalization of the spectrum intensity. In order to observe the SERS only and avoid any normal Raman scattering of BA, the concentration of BA solution is reduced to 10-2 M. Five series sol-gels by various amounts of doped silver particles are prepared and processed under heat treatments with eight different temperatures ranging from room temperature to 450℃. The experimental results indicate that 200-300℃ heat treated sol-gels shows no SERS spectra regardless of the amounts of silver particles doped. However, sol-gels heat treated under other temperatures not only show significant SERS effect, but also had an optimum SERS as the concentration of silver particles is about 20g per TMOS mole. These different behaviors are related to the interactions in between BA and silver particle, BA ‘s coverage on the silver particles as well as the possible influence of silver particles on the sol-gel’s structures. The analysis and discussions in this thesis will not only offer the optimal SERS condition for the sol-gel’s preparations, but also will be beneficial to the study of detecting scarce elements in the future.
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