奈米銀化CD-R基板在表面增強拉曼散射(SERS)上之研究與應用

The Study and Application of Nanosilver/CD-R Substrate in Surface-Enhanced Raman Scattering (SERS)

駱亮安(Luo Liang-An)

指導教授 ： 林震煌

國立臺灣師範大學/理學院/化學系/碩士(2016年)

https://doi.org/10.6345/NTNU202204185

摘要

一般拉曼光譜儀搭配顯微鏡會使用載玻片作為樣品基板，然而樣品乾燥在基板上時，樣品會出現咖啡環效應，使得樣品分佈不均勻，尤其在偵測低濃度樣品時，會讓實驗更為困難，因此本研究試圖使用CD-R作為基板，並搭配奈米粒子作表面增強拉曼散射(SERS)，解決樣品分佈不均及難以測得低濃度的問題。
本研究使用具有疏水性表面的CD-R作為表面增強拉曼光譜的基板。去除紀錄層和保護層以後，以SEM (scanning electron microscope)發現CD-R的表面具有微陣列結構，每一個陣列縫隙約為341 nm。滴約直徑2 mm大小的液珠在CD-R和載玻片上，以接觸角儀測出CD-R接觸角為84°，載玻片的接觸角為20°，此顯示出CD-R提供較高的疏水性表面，為使用CD-R基板可以減少咖啡環效應的原因。
預混合NH2OH · HCl (1.67 × 10-3 M/90 mL) 和NaOH (0.519 M/0.577 mL)，在2000 rpm的轉速攪拌下，加入0.01 M AgNO3 10 mL，持續攪拌4.5分鐘後完成土黃色的奈米銀膠體溶液。
在CD-R滴奈米銀膠體溶液自然乾燥後，奈米銀粒子可以推積在微陣列縫隙中，奈米銀膠體溶液的UV-Vis的吸收在406 nm，奈米銀粒子大小約20 nm，這種奈米銀粒子大小在雷射照射下，可以感應出表面電漿共振。為了評估奈米銀CD-R基板的表現性，對-胺基苯硫酚 (4-ATP)和孔雀石綠(MG)選作測試樣品，p-ATP上的硫原子易和奈米銀粒子鍵結，此共價鍵會讓C-S的能量下降，造成1089 cm-1 (拉曼訊號) 偏移至1077 cm-1 (SERS訊號)，估算出的增強因子為3×〖10〗^6。

關鍵字

咖啡環效應 ； 奈米粒子 ； 表面增強拉曼散射

並列摘要

With a high hydrophobic surface, CD-R was selected as the substrate of SERS (Surface Enhanced Raman Scattering) in this study. After removing the recording and protective layers, it was found that the surface of the CD-R was constructed with microarray structures; the width between each microarray was approximately 341 nm, observed by SEM (scanning electron microscope). By using a contact angle-meter, to a drop of water (diameter of 2 mm), the contact angles of the CD-R and a regular glass slide were found to 84° and 20°, respectively. It reveals that the CD-R substrate provides higher hydrophobic feature than glass slide. This is also the reason for why the use of CD-R substrate can avoid coffee ring effect.
Nano-silver colloid solution was prepared by pre-mixing NH2OH · HCl (1.67 × 10-3 M/90 mL) and NaOH (0.519 M/0.577 mL). After vigorous stirring at speed 2000 rpm, 0.01 M AgNO3 10 mL was added to the above solution and continue stirring in 4.5 minutes. After this, a wheat nano-silver colloid Solution was completed. When a drop of nano-silver colloid solution was dropped on the CD-R substrate, it would be spontaneously dried, and then the nano-silver particles can be uniformly deposited on the surface, leading to make silver-CD-R substrate. The wavelength of maximum absorbance was 406 nm. The sizes of the nano-silver particles on CD-R were about 20 nm, which size was useful to induce a surface plasma resonance when a laser was used. In order to evaluate the performance of the silver/CD-R substrate, 4-ATP (p-aminothiophenol) was selected as the test sample. The findings show that the sulfur atom was easy to bond with nano-silver particles. We found that a covalent bond might be formed between the sulfur atom and nano-silver particles, and as a result, the energy of C-S bond was decreased, since the energy of a C-S bond was decreased from 1088 cm-1 (Raman signal) to 1077 cm-1 (SERS signal). Based on this signal, a 3000 fold enhancement factor was calculated.

並列關鍵字

coffee ring effect ； nanoparticles ； surface-enhanced Raman Scattering

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