MoS2间隔双金属复合结构光纤SERS-SPR传感层的研究

High-sensitive optical fiber SERS-SPR can realize the fast, real-time and accurate detection, which plays an important role in the medical diagnosis and treatment and public health. The SERS-SPR signals achieved by the commonly used metal sensor layer with strong background fluorescence are variant, low-sensitivity, low-stability and poor-reproducibility. The research in our group directly fabricates the MoS2 spaced bi-metal hybrid structure with the method of electron-beam lithography and thermal decomposition. By virtue of the bi-metal SPR, we can increase the hot spots and further improve the sensitivity of the SERS signal and the resolution of the SPR signal via narrowing the resonance peak. Besides, the exciton in MoS2 can powerfully couple with the SPR in metal, which will further enhance the SERS-SPR signal. The MoS2 can effectively adsorb the molecules and passivate the metal layer improving the stability and reduce the background fluorescence. With the assist of the Comsol, we investigate the tunable rule of the resonance peak for the bi-metal structure, analyze the mechanism of the couple of exciton and SPR and reveal the enhanced mechanism. With the proposed hybrid structure, we aim at achieving the SERS-SPR dual-mode and high-sensitivity signal based on the optical fiber and provide the more comprehensive sensing information to reduce the misinformation during identifying the biomolecule.

高灵敏光纤表面增强拉曼散射-表面等离子体共振（SERS-SPR)技术可实现快速、实时、准确的检测，对医学诊疗和公共卫生等具有重要的作用。通常的金属SERS-SPR传感层存在信号易变形、灵敏度低、稳定性差、背景荧光强、可重复性差等缺点。本项目利用电子束光刻和热分解的方法原位制备二硫化钼间隔双金属的复合结构，通过双金属结构的SPR效应，增加热点的分布提高SERS信号的灵敏度，调谐窄化共振谱线提高SPR信号的分辨率；二硫化钼间隔层中的激子可与金属等离子体形成强耦合作用，进一步增强SERS-SPR信号，同时可有效吸附分子、钝化底层金属提高稳定性并可抑制背景荧光；理论研究双金属结构共振峰的可调谐规律，分析激子与等离子体耦合作用的机制，揭示增强机理。最终实现基于光纤SERS和SPR的双模式、高灵敏光谱信号的稳定输出，获得更为丰富全面的信息以减少鉴定生物分子时的误报。

本项目利用热分解和水热合成的方法原位制备二硫化钼间隔双金属的复合结构，通过双金属结构的等离激元效应，增加了热点的分布并提高了SERS信号的灵敏度，实现了共振谱线调谐窄化提高了SPR信号的分辨率；二硫化钼间隔层中的激子与金属等离激元形成强耦合作用，进一步增强了SERS-SPR信号，同时可有效吸附分子、钝化底层金属提高稳定性并可抑制背景荧光；理论研究了双金属结构共振峰的可调谐规律，并揭示了增强机理，实现了基于光纤SERS和SPR的双模式、高灵敏光谱信号的稳定输出。