基于贵金属合金/Ⅱ-Ⅵ族半导体复合基底的SERS增强机理研究

贵金属合金/Ⅱ-Ⅵ族半导体复合型表面增强拉曼散射（SERS）基底，具有良好的SERS灵敏性、生物相溶性和稳定性，在临床医学、表面电化学等领域具有广阔的应用前景。但其目前的主要问题是表面等离子体激元（SP）在调制电荷转移跃迁（CT）中的作用不明确，多种SERS增强机理之间难以平衡，限制了基底的功能性和适用领域。而揭示基底SERS活性的微观增强机理和调控规律是解决上述问题的关键。本项目拟将电磁场数值仿真和量化计算方法结合，模拟目标体系的局域电场、光谱和电子性质，研究表面等离子体激发和电子跃迁过程，揭示SP对CT的调制机制，分析成键作用、SP和CT对SERS的贡献，明确激发波长、基底的结构和电位、吸附环境和外加电场等因素与SERS效应的内在联系，进而阐明该体系SERS活性的增强机理和调控规律。本项目的开展将为优化目标体系的SERS活性、设计优秀的合金/半导体复合SERS基底提供理论支撑。

The surface enhanced Raman scattering (SERS) substrate composed of noble metal alloys and Ⅱ-Ⅵ semiconductors has good SERS activity, biocompatibility and stability, and has broad application prospects in clinical medicine, surface electrochemistry and other fields. At present, the main problem is that the role of surface plasmon (SP) in modulated charge transfer transition (CT) is not clear, and it is difficult to balance various SERS enhancement mechanisms, which limit the functionality and application of the substrate. The key to solve the problem is to reveal the micro mechanism and regulation rule of SERS activity. In this work, the electromagnetic field numerical simulation and quantitative calculation method are combined to simulate the local electric field, spectrum and electronic properties of the target system. By studying the surface plasmon excitation and electron transition, the modulation mechanism of plasma on CT will be revealed. The intrinsic relationship between several factors and SERS effect will be clarified, such as excitation wavelength, structure and potential of substrate, adsorption environment and external electric field, etc., and then the enhancement mechanism and regulation rule of SERS activity for this system will be clarified. This work will provide theoretical support for enhancing the SERS activity of target system and designing excellent alloy/semiconductor composite SERS substrates.