金纳米粒子自组装薄膜的光谱学研究

采用柠檬酸钠还原氯金酸制备了金胶体，通过静电自组装制备了金纳米粒子薄膜，利用紫外-可见光吸收光谱等对金纳米粒子薄膜进行了光谱学研究，紫外-可见光吸收光谱表明所制备的金溶胶为单分散体系，根据自组装薄膜的X-射线衍射谱，由谢乐公式估算金纳米粒子的粒径约为21nm；X-射线光电子能谱显示氯金酸的还原反应比较完全，金主要以Au^0的价态存在，金胶体粒子通过静电吸引机制组装到PDDA改性的衬底表面；紫外-可见光吸收光谱和表面增强拉曼光谱显示，由于粒子间的电磁耦合，自组装金纳米粒子薄膜表现出协同等离子体共振吸收行为和表面增强拉曼散射效应。

Spectroscopic Studies on Electrostatically Self-assembled Gold Nanoparticulate Thin Films

Colloidal gold was prepared by citrate-induced reduction of hydrogen tetrachloroaurate. Gold nanoparticulate thin films were built up using the electrostatic self-assembly technique and characterized by different spectroscopes. The UV-Vis absorbance spectrum indicated that the gold colloid was a monodisperse suspension. The calculation using the Scherrer's equation on base of the X-ray diffraction spectrum indicated that the average size of the gold particles assembled on the substrates was about 21 nm. The X-ray photoelectron spectra showed that the reduction of hydrogen tetrachloroaurate was almost complete and that the gold was present in the thin films largely as Au zero. The X-ray photoelectron spectra also showed that the gold particles were attracted and fixed onto the PDDA-modified substrates by electrostatic forces. The UV-Vis absorbance spectra and the surface enhanced Raman scattering spectra indicated that, arising from the interparticle coupling, the gold nanoparticulate thin films displayed strong collective plasma resonance absorption and sur faced enhanced Raman scattering effect.