應用石墨烯以迦凡尼置換法製做表面增強拉曼散射活性金奈米複合性基材

近年來，表面增強拉曼散射(SERS)吸引越來越多人投入研究，主要歸因於SERS其本身的幾項優勢，包括對偵測物質的高度敏感性、不受水的訊號干擾以及可以得到偵測分子的外部結構訊息等。因此，為了更加廣泛地應用SERS之特性，本篇研究將針對SERS對偵測物的敏感度及高再現性的偵測結果，開發出具有表面增強拉曼散射活性之複合性金奈米基材。在此研究中，我們運用迦凡尼置換法(galvanic displacement)製備我們的複合性金奈米基材，因金與鋁基板之間有不同的電位差而發生自身氧化還原，使金奈米粒子沉積在鋁基板的表面。並且利用調控不同的控制變因，如四氯化金酸水溶液濃度、迦凡尼置換反應時的溫度、改變溶液pH值、添加不同種類陰離子等，以控制所製造出金奈米粒子之形態以及粒徑大小，並進一步影響SERS訊號之效果。同時，本實驗也利用鋁基板表面石墨烯的有無，觀察兩不同基材間金奈米粒子表面形態的差異，做為探討石墨烯用於製造複合式金奈米基材的影響以及SERS訊號之增強效果。初步研究顯示，石墨烯結合基材表面所吸附分子，確實能使表面增強拉曼散射複合性金奈米基材具有良好的拉曼散射增強效果，而此基材之增強因子可達約107。

關鍵字

表面增強拉曼散射；金奈米粒子；石墨烯；迦凡尼置換法；奈米基材

並列摘要

Surface-enhanced Raman scattering (SERS) has attracted increasing attention in the past few decades due to the high sensitivity, minimal water interference, and abundant molecular information that can be obtained by SERS. To further increase the applicability of SERS, diverse approaches have been attempted to prepare SERS active substrates with increasing sensitivity and reproducibility. In this study, galvanic displacement (GD) was utilized to fabricate SERS active hybrid nanocomposites. Since the reduction potentials between gold and aluminum are different, gold nanoparticles (Au NPs) were deposited spontaneously on the surface of aluminum substrates. Meanwhile, parameters that affect the morphologies of the fabricated composites, including the concentration of HAuCl4, the temperature of the Galvanic displacement, and the addition of anion additives were studied to correlate the morphologies of nanocomposites and the enhancement factors of the SERS signals. A series of detailed studies were carried out to explore the contribution of graphene in the system. In addition, the enhancement factor (intensity increase of SERS) and the morphologies of the hybrid composites were compared in the presence and absence of graphene. Based on the preliminary results, it was found that the presence of graphene can further enhance the Raman signal of molecules adsorbed on the SERS active hybrid composites prepared in this study. The enhancement factor of this substrate about 107.