半胱氨酸作为耦联剂制备的纳米银膜上的SERS研究

Surface Enhanced Raman Scattering Study of Silver Nanoparticles Prepared by Coupling Molecules of L-Cysteine

在直流10V电压下电解聚乙烯醇和硝酸银的混合液3h制备纳米银胶,将经过半胱氨酸修饰后的载玻片浸入银胶24h制得纳米银膜。用紫外可见分光光度计对银胶进行了观测,由于其吸收峰半高宽较窄可知银胶中纳米银颗粒粒径分布较为均匀。同时,使用扫描电镜对银膜进行了表征。通过对半胱氨酸分子SERS信号的分析得出了纳米银粒子在玻璃表面上可能的组装方式。以结晶紫(Crystal Violet)和孔雀石绿(Malachite Green)作为探测分子,采用便携式拉曼光谱仪测得两种分子不同浓度下的SERS谱。发现该方法所制得的纳米银膜有很好的表面增强效果。最后分析了半胱氨酸分子SERS信号对探针分子光谱的影响。

Nano silver colloids were prepared by electrolysis method.Mixture aqueous solution of polyvinyl alcohol（PVA）and AgNO3 were used as electrolyte.A 10-V direct current was applied Ag rods for 3h.The glass slides were modified by L-cysteine.Then,the glass slides were kept in the silver colloids for 24h.Silver colloids were observed by the UV-Vis spectrometer.It can be seen that the size of silver nanoparticles is in a narrow size distribution.The nano silver film was studied by the Scanning Electron Microscopy.We compared the normal Raman spectrum（NRS）of L-cysteine（solid）with SERS spectra of L-cysteine molecules and obtained the possible assembling structures of nano silver film.The SERS spectra of Crystal Violet and Malachite Green with different concentrations were measured by Portable Raman Spectrometer.The results show that highly efficient surface-enhanced Raman scattering（SERS）was observed from Crystal Violet and Malachite Green on silver film.Finally,we discussed the influence of SERS spectra between probe molecule and L-Cysteine.