高效光纤型SERS探针的界面设计、可控制备及性能研究

With its compactness and higher sensitivity than SERS substrate, the optical fiber surface enhanced Raman scattering (SERS) probe may find a variety of applications in trace detection, high sensitivity sensing, and so on. However, due to the high chemical stability of the silica-based optical fiber, it is hard to realize the strong bonding between noble metal nano-structure and the silica-based optical fiber, and also hard to prepare the noble metal nano-structure with controlled morphology and scale on the surface of the optical fiber. In this project, by producing activated groups on the surface of silica-based fiber, we can choose specific modified molecules with suitable functional groups, then use such specific modified molecules as the link, and finally make it possible to form the stable and strong chemical bond between the silica-based optical fiber and nobel metal nano-structure. By further choosing specific modified molecules, and clarifying the mechanism of nucleation and crystal growth regulation mechanism of the noble metal nano-structure on the fiber surface, the morphology and scale of the noble metal nano-structure formed on the fiber surface can be adjusted and controlled by using seed growth method based on the liquid-phase chemical synthesis. This project may greatly increase the mechanical and physical strength of fiber SERS probes by using the modified molecular grafting technique to form the stable and strong chemical bond between nano-structure and the silica-based optical fiber, and improve the detection sentitivity of optical fiber SERS probe by optimizing the morphology and scale of noble metal nano-structure on the optical fiber surface. Therefore, executing this project plan holds remarkable significance in both scientific research and technological progress.

光纤SERS探针结构紧凑，且具有比宏观SERS基底更高的检测灵敏度，在痕量检测、高灵敏度传感等领域有着重要的应用前景。但因石英光纤的化学稳定性好，使得光纤SERS探针面临着贵金属纳米结构难以与光纤表面高强度结合且难以调控纳米结构形貌与尺度等困难。本项目拟通过活化石英光纤表面，优化筛选出具有合适官能团的修饰分子，再以这种修饰分子为纽带，实现石英光纤与贵金属纳米结构间的高强度化学键合；通过进一步筛选修饰分子，阐明贵金属纳米结构在功能化光纤上的成核机理以及晶核生长调控机制，利用基于液相化学合成的种子生长法，实现对光纤表面的贵金属纳米结构形貌尺度的调控。通过本项研究，利用修饰分子嫁接技术实现石英光纤与贵金属纳米材料异质结构界面间的化学键合，提高纳米光纤SERS探针机械与物理强度；通过光纤上贵金属纳米结构形貌和尺度的调控，提高光纤SERS探针的探测灵敏度。因此，本项研究具有重要的科学意义和实用价值。

光纤SERS探针具有结构紧凑、可以实时监测、抗电磁干扰、能够用于遥测等优点，因此可以应用于远距离探测、原位检测、以及活体检测等领域。本项目以光纤SERS探针研制中的界面设计及可控制备等科学问题为切入点，已完成的工作总结如下：（1）提出了制备光纤SERS探针的新方法，在光纤上获得了具有片状银纳米结构的光纤SERS探针，其具有很高的SERS活性及重现性，并且对光纤锥结构进行了优化设计。（2）探明了光纤活化及表面功能化的方法，并辅以激光诱导法实现了一系列硅烷化光纤探针的制备，而硅烷化的光纤表面有利于提高贵金属纳米结构的沉积密度，从而有益于提高光纤SERS探针的灵敏度并解决了光纤上贵金属纳米结构的稳定结合。（3）实现了通过高压釜合成法对光纤表面上贵金属纳米结构的形貌和尺度调控，与其它制备方法获得的光纤SERS探针相比，探测极限得到进一步的提升。（4）发展了光纤SERS探针的双基底探测方案，分别通过激光诱导在光纤锥面制备银纳米颗粒，同时在待测液中加入高活性的SERS基底，结果表明双基底光纤探针的SERS增强要高于单一基底所产生的信号以及两者之和。（5）研究了在探针制备过程中直接调控颗粒尺寸，进而在光纤探针上得到了具有密排结构且稳定的SERS活性材料，该探针展现了很高的灵敏度、长期稳定性、很好的重现性以及优越的可循环利用性。上述研究工作取得了多项具有创新性和系统性的研究成果，在项目实施三年来，已在国际学术期刊Analyst，Appl. Phys. Lett.，RSC Adv.，New J. Chem.，ChemistrySelect上发表了标注有国家基金资助的研究论文。本项目的完成为光纤SERS探针的研制及应用提供了新的方法和思路，所制备的若干种高效光纤型SERS探针在分析化学、生物传感及环境监测等领域有潜在的应用价值。