理论支持下的周期性金/银纳米线阵列的构筑及针尖增强拉曼散射技术对痕量物质的检测研究

Surface-enhanced Raman spectroscopy has the advantages of high sensitivity and rapid detection, and it plays an important role in the fields of biology, medicine and industry. The sensitivity and stability of the assay are inseparable from the choice of substrate. The order of nanostructures plays a decisive role in the uniformity of the surface Raman enhancement spectrum. However, how to prepare ordered precious metal nanostructures remains a challenge. In this paper, the finite-difference time-domain method is used to analyze the electric field distribution of nanowire arrays under different structural parameters. The optimized array structure is selected based on the simulation results. A porous alumina template is prepared by a two-step anodization method, and various porous alumina structures are obtained by controlling experimental parameters. Using these porous alumina templates, noble metal nanowire arrays of different morphologies are synthesized. The preparation of a substrate with high sensitivity and stability is achieved. Tip-enhanced Raman spectroscopy (TERS) technology has the advantages of high spatial resolution and detection sensitivity. In this paper, TERS enhanced needle tips are obtained by evaporation, sputtering. The probe molecules are used to compare the effects of noble metal periodic nanowire array substrates with different structures, different sizes and different positions on Raman detection. Finally, Raman scattering studies are carried out on trace substances in water to complete the detection of trace pollutants in water.

表面增强拉曼光谱具有高灵敏度、检测快速等优点，使其在生物、医学及工业领域据着重要地位。而检测的灵敏度和稳定性与基底的选择密不可分。纳米结构的有序性对表面拉曼增强光谱的均匀性起决定性作用，然而如何大面积制备有序的贵金属纳米结构依旧是个挑战。本课题拟利用时域有限差分法分析模拟纳米线阵列在不同结构参数下的电场分布，根据模拟结果选出最优化的阵列结构。然后采用两步阳极氧化法制备多孔氧化铝模板，通过控制实验参数得到多种多孔氧化铝结构。利用这些多孔氧化铝模板，合成不同形貌的贵金属纳米线阵列，以实现对高灵敏度和稳定性基底的制备。针尖增强拉曼光谱（TERS）技术有高的空间分辨率和探测灵敏度的优点。本课题通过蒸镀、溅射等方法获得TERS增强针尖；采用探针分子比较不同结构，不同尺寸，不同位置下的贵金属周期性纳米线阵列基底对拉曼检测效果的影响；最终对水中的痕量污染物做拉曼散射研究，以完成对水中痕量污染物的检测。

表面增强拉曼光谱（SERS）具有很高的灵敏度和选择性等特点，在化学分析、环境污染物等领域发挥了重要作用。检测的灵敏度与基底的选择密不可分。所以，基底的发展正是拓宽应用领域的关键。本课题首先通过旋涂结合静电自组装的方法制备氧化石墨烯/银纳米颗粒多层复合薄膜。将复合薄膜退火得到石墨烯/银纳米颗粒多层复合薄膜。退火后得到的复合薄膜的最低方块电阻仅为0.392KΩ/sq。结果可表明，该复合薄膜具有优异的光电性能和良好的稳定性，可用于高性能光伏器件。为进一步探索贵金属纳米材料基底对拉曼散射信号的影响。课题组同时还制备出由高指数值{651}面包围的六面体金纳米颗粒，其对甲醇的电氧化表现出优异的催化活性。此外，高指数金纳米颗粒基底具有优异的SERS性能，对4-氨基噻吩(4-ATP)的检测限可低至(10-10M)。在电催化、SERS检测和甲醇燃料电池的实际应用中具有很大的潜力。同时，为通过贵金属纳米材料提高基底的表面增强拉曼散射性能，课题还合成了凹八面体金@金银纳米颗粒。最后，通过溶剂蒸发自组装策略制备了均匀排列的凹八面体Au@AuAg NPs组装体。凹八面体Au@AuAg NPs的SERS增强系数为1.3×107，检测限低至10-10M。该工作为凹形结构的双金属NPs开辟了新的途径，在光学、SERS检测等领域具有广阔的应用前景，该结构对痕量有害分子分析具有重要意义。最后，采用多元醇还原法，通过调节反应时间，反应温度等因数，制备出形貌均一，纯度较高的多尺寸银纳米线。随着纳米线直径的增大，纳米线薄膜的导电性能也增强。银纳米线薄膜的最低薄层电阻仅为1.092Ω/sq。该纳米线基底具有优异的光电性，在光学、SERS检测等领域具有广阔的应用前景。