Preparation of Gold and Silver Nanostructural Materials on Germanium Substrates for Surface Enhancement Infrared Absorption Spectroscopy

• Main Authors: You-Hsien Chen, 陳宥銜
• Other Authors: 楊吉斯
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/88282910391915445039

碩士 === 國立中興大學 === 化學系所 === 95 === In this work, an electroless displacement method was developed to produce nanoparticles on germanium for surface enhancement infrared absorption (SEIRA) measurements. By controlling the reaction conditions, this developed method produced metal nanopatricles that exhibit large surface enhancement effects. Two goals in this work were targeted including preparation of core-shell Ag@Au and Au@Ag nanoparticles and investigation of additives in preparation of Ag nanoparticles for SEIRA. Utilizing p-Nitrothiophenol (p-NTP) as probe molecule, the factors influence the enhancement were examined and optimized. By examined with scanning electron microscope (SEM), the morphologies of the produced nanoparticles were also investigated and correlated with surface enhancement effect. In the production of Ag@Au or Au@Ag nanoparticles, a consecutive method was used and both the influences of the reaction concentration and time were examined. Results indicated that the produced Ag@Au or Au@Ag nanoparticles did not provide significant increase of surface enhancement but modification of the surface of nanoparticles was feasible. By reaction with 1 mM AgNO3 for 15 min following reaction in 1 mM HAuCl4 for 5 min, the produced nanoparticles showed the largest surface enhancement effect among the tested conditions. In the examination of the effect of additives, several chelating agents were selected and examined. With the assistance of chelating agents, the produced Ag nanoparticles showed significant increase of the SEIRA signals. Among them, ethylenediamine tetraacetic acid (EDTA) showed the most significant influence to the production of suitable Ag nanoparticles for SEIRA. An enhancement factor of 300 was obtained in this study. Besides the effect of species of chelating agents, effect of concentration of silver nitrate and additives, and the reaction time were also examined. Optimal condition was found when the mole ration of AgNO3 and EDTA was 1:1.