Photoreduction assisted method in preparation of metallic nanoparticles on ZnSe crystals for surface-enhanced infrared absorption spectroscopy

• Main Authors: Han-Ju Ku, 古涵如
• Other Authors: Jyisy Yang
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/49257632518379161215

碩士 === 國立中興大學 === 化學系所 === 102 === Surface-enhanced infrared absorption (SEIRA) spectroscopy has gained large attention because it is potentially a very sensitive means for chemical analysis. This SEIRA effect is commonly observed when molecules adsorbed or nearby metal islands and an enhancement factor of the IR absorption can be much larger than 100 if the used metal islands have proper size and morphologies. To prepare active substrate for SEIRA effect, ZnSe was selected in this work as even it is frequently used IR window material, none of the literature method can effectively produce proper nanoparticles on ZnSe with the exception of vapor deposition. Therefore, to improve the application of SEIRA for analytical purpose, a new method to produce gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) on ZnSe crystal was proposed, which was based on combination of electroless displacement method and photoreduction method. Several parameters, such as the concentration of metal ions, the photo irradiation time, and the additive, affect the performance in production of AuNPs and AgNPs. These parameters were systematically studied for their impacts to the performances of the produced metal nanoparticles. Also, the produced nanoparticles on ZnSe crystals were scanned by electron scanning microscope (SEM) to observe the morphologies of the produced nanoparticles. p-Nitrothiophenol (p-NTP) was used to probe the performances of SEIRA for the produced nanoparticles and the observed SEIRA signals were used to correlate with their corresponding SEM images. Based on SEIRA signals and the observed SEM images, the produced AuNPs and AgNPs, which exhibit best SEIRA performances, were round in shapes with 50 and 20 nm diameter. On the other hand, both AuNPs and AgNPs were successfully prepared on ZnSe crystal with an enhancement factor of 6~19.