表面增強拉曼散射效應具有高靈敏度及高選擇性的特性，因此在生醫及化學分子檢測上受到注目。目前普遍接受的增強機制可分為電磁增強及化學增強，其中電磁增強機制主要歸因於金屬粒子本身提供的表面等離子共振效應，而化學機制則是由許多不同的效應所造成。因此，開發出可控制電磁、化學增強機制的奈米材料合成方法，及研究對於表面增強拉曼散射的基礎性質探討或是其創新應用技術都是一大邁進。石墨烯奈米帶為獨特結構的奈米碳材，可以藉由其寬度的變化來控制其電子屬性，使其具有在表面增強拉曼散射、能源、生醫應用上的潛力。
本論文著眼於開發及設計出一個具備電磁增強及化學增強性質的奈米複合材料。透過文獻的搜索，我們選用了銀奈米粒子和硼摻雜石墨烯奈米帶來合成複合材料。首先我們透過化學裁剪法來合成寬度為4到5奈米的石墨烯奈米帶，此外藉由在大氣常壓下的前處理異質摻雜奈米碳材合成方法，我們成功合成出硼摻雜石墨烯奈米帶，並透過X光光電子能譜儀分析出其硼原子含量為1.4原子百分比。為了更有效的提升表面增強拉曼散射的效果，我們利用大氣常壓微電漿系統來輔助合成奈米複合物，並進行有系統的材料特性鑑定及其表面增強拉曼散射性能測試，其結果顯示出，在對於常見的羅丹明6G分子檢測上，我們的奈米複合材料可以達到低至10-12莫爾濃度的偵測極限，並計算出其增強因子數值為1.9 x 1012。除了單純對材料偵測性能的測試，我們更加有系統地利用不同特性的待測分子及奈米碳材去研究其化學增強效應的機制，研究成果發現在我們的系統下，材料吸附能力及其與雷射光源能量的共振效應為主要的化學增強機制。為了驗證此奈米複合材料在生醫分子感測上的可行性，我們也在表面增強拉曼散射的系統下來進行葉酸分子的偵測，發現其最低偵測濃度可以達到10-8 莫爾濃度。

Surface-enhanced Raman scattering (SERS) provides high sensitivity and selectivity on molecule detection, making it attractive for biomedical and chemical detections. Generally there are two mechanisms to influence the SERS enhancement: electromagnetic mechanism (EM) created by the metals with surface plasmon resonance (SPR) property and chemical mechanism (CM) caused by several possible aspects. The development of synthetic method to produce nanostructures with controllable EM and CM properties will lead to important advances on both fundamental study and innovative applications for SERS-based biomedical detections. Graphene nanoribbons (GNRs) represent a unique structure of carbon nanomaterials with controlled electronic properties by tuning their widths, making them can be potentially useful as the SERS-active substrate and used in other applications including energy, composites, biomedical and electronics.
Here we report a rational design to develop a SERS-active nanocomposite with improved EM and CM properties. Toward this goal, we prepared silver nanoparticle (AgNP)/Boron-doped GNR (B-GNR) composites using a sequential reaction route. First we synthesized GNRs with averaged width around 4 to 5 nm by chemical unzipping the singled-walled carbon nanotubes (SWCNTs). Additionally, the prepared GNRs were doped with B atoms by a controlled carbonthemic reaction under argon (Ar) flow at atmospheric pressure and the B dopant concentration was about 1.4 atomic percentage (atom%) according to the X-ray photoelectron spectroscopy (XPS) analysis. Ag NPs with 10 nm averaged size were decorated onto the B-GNRs surface through an atmospheric-pressure microplasma-assisted redox reaction. Detailed materials characterizations including transmission electron microscopy and UV-Vis spectroscopy show that Ag/B-GNR composites were successfully synthesized in our experiment. We further systematically studied the Raman response of the AgNP/B-GNR composite using Rhodamine 6G (R6G) as the Raman probe molecules. The result indicates that the AgNP/GNR composite shows superior SERS performance with low detection concentration of 10-12 M of R6G and high enhancement factor (EF) of 1.9×1012. We further systematically studied the CM enhancement via different probing molecules and substrates. Results show that SERS performance is strongly influenced by the laser alignment resonance effect and the substrate surface adsorption ability. To demonstrate the feasibility of using AgNP/B-GNR as the SERS substrate for detecting the folic acid (FA) molecule, we perform a series of SERS measurements under different FA concentrations. The result indicated that the as-produced nanohybrid can reach 10 nanomolar-level detection. Overall, our study provide the conception to design the applicable SERS substrates.

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