2-氨基苯硫酚NIR-SERS光谱及其在纳米银表面吸附行为分析

NIR-SERS and Adsorption Behavior Studies of 2-Aminothiophenol (2-ATP)Adsorbed on the Surface of the Silver Nanofilm

本文采用静电自组装的方法制备了二维纳米银膜。UV-vis吸收光谱显示其等离子体共振吸收带位于400+900nm的光谱范围,延伸到了近红外区,可以较好的匹配785nm的近红外激发光源。以该纳米银膜为基底,对2-氨基苯硫酚(2-ATP)分子进行了近红外表面增强拉曼散射(NIR-SERS)检测,获得了重复性良好的NIR-SERS光谱图。实验表明:以2-ATP为探针分子时,该纳米银膜的NIR-SERS增强因子达到2.19×109。同时,本文采用密度泛函理论(DFT),以B3LYP/6-31G为基函数,对2-ATP分子进行结构优化和普通拉曼光谱(NR)计算,发现理论值和实验值吻合较好。此外,对2-ATP的NIR-SERS谱带进行了归属分析,发现当2-ATP分子在纳米银表面吸附时,是以-SH基团吸附到银表面,且同时-SH基团会被纳米银氧化。

Two-dimensional nano scale silver films were prepared using the electrostatic self-assembled method in this paper. UV-vis adsorption spectrum of the silver nanofilm shows that the plasmonic resonance band is in the region of 400-900 nm, which extends to the near infrared region. This plasmonic resonance band is able to be matched with the 785 nm excitation source. With 2-ATP used as the tested molecules, we have obtained the near infrared surface-enhanced Raman scattering （NIR-SERS） spectra of 2-ATP adsorbed on the silver nanofilm with good spectral reproducibility. Meanwhile, the enhancement factor （EF） of this silver nanofilm was evaluated using the tested molecule of 2-ATP, and the EF is up to -2.19×10^9. The geometry optimization and calculated wavenumbers of 2- ATP and 2-ATP-Ag are performed with DFT, B3LYP functional, and the 6-31G/ LanL2DZ basis set. The calculated wavenumbers match well with the experimental data. In addition, the adsorption behavior of the 2-ATP molecule adsorbed on the surface of sil- ver nanoparticle was also analyzed and found that the 2-ATP molecule adsorbed on the sur-face of silver through the group of --SH. Meanwhile, the --SH group will be oxidized by Ag nanoparticles when 2-ATP molecules adsorbed on the surface of silver.