Silver Nanostructure for Efficient SERS Substrate and Electrochemical Detection

• Main Authors: Jui-Hung Hsu, 徐瑞鴻
• Other Authors: Yu-Kuei Hsu
• Format: Others
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/29hu8t

碩士 === 國立東華大學 === 光電工程學系 === 105 === First, we use a simple dip-coating route to deposit silver nanowires (Ag NWs) on coffee filter (CF), which would function as a new type substrates of SERS and non-enzyme biosensor for detecting the H2O2 in this study. For SERS, the Ag NW/CF substrate exhibits low detection limit of 1x10-11 M for 4-Aminothiophenol (4-ATP). And for biosensor, the Ag NW/CF electrode exhibits detection limit of 0.1 mM and high sensitivity of 219 mAmM-1cm-2 for detection of H2O2 in concentration range 100 M ~ 25 mM. In order to find out the way to enhance the efficiency in the detections of H2O2 and SERS signal, we utilized the electrochemical growth technique to fabricate dendritic Ag NW on FTO substrate for achieving the low detection limit. Because the branched Ag NW/FTO has large active surface for electrocatalytic reaction, our results show a sensitivity of 1.44 mAcm-2mM-1 to H2O2 and the concentration range from 0.25M to 2.6 mM with a low detection limit of 0.25 mM. In addition, the branched Ag NW also exhibited an excellent and significant performance for molecular sensing by using SERS with ultra-low concentration detection limit of 1x10-16 M for 4-ATP. Finally, the branched Ag NW/FTO functions as photoelectrode for the detection of H2O2 under illumination based on the characteristics of SPR and electro-catalytic effects. In this study, we observed that the maximum photocurrent density of -0.2 mAcm-2 can be reached at potential -0.6 V v.s. Ag/Ag Cl and the reason is due to localized surface plasmon resonance leading to the contribution of the hot electrons in photocurrent.