基于二维材料亚纳米腔的三明治（金颗粒/腔/金膜）耦合系统光学特性研究

Metal nanoparticles/spacer/metal film sandwiched system receives intensive attention among plasmonics recently. The properties of spacer materials (thickness, dielectric constant, and electrical conductivity) play an important role in the optical coupling sandwiched system. However, the current spacer materials such as SiO2 cannot reach the requirement of sub-nanometer thickness，which impedes the study of optical properties in the sandwiched system. Although graphene with sub-nanometer thickness can solve the thickness issue, the effect of another property of materials electrical conductivity on the optical property is still not well studied until now. Here, Au NPs/ sub-nanometer spacer / Au film is proposed by introducing the two-dimensional materials with different electrical conductivity (i.e. graphene, MoS2, and BN) as sub-nanometer spacer. The optical coupling properties of the as-proposed system based on the sub-nanometer spacer is investigated experimentally and theoretically and then the effect of electrical conductivity on the coupling effect has been clarified. In addition, the ultra-sensitive surface enhanced-Raman scattering (SERS) device would been achieved after the study of application in SRES. Our current study paves the way to realize sub-nanometer spacer, provides comprehensive understanding to the coupling mechanism between metal nanoparticle and metal film with sub-nanometer spacer, and opens a new route for ultra-sensitive sensor.

金属纳米颗粒/腔/金属膜三明治系统光学特性是当今金属等离子体光学领域的前沿研究课题。腔材料的厚度、介电常数和电导率等性质对其光学效应具有重要影响，传统二氧化硅等腔材料无法实现亚纳米腔限制了光学效应的研究，石墨烯具有亚纳米厚度的特征是解决上述问题的有效途径。然而，亚纳米腔下电导率特性对三明治结构光学耦合特性的影响尚未厘清。针对这一问题，本研究将具有不同电导率的石墨烯、硫化钼和氮化硼等二维材料引入到“金颗粒/亚纳米腔/金膜结构”的构筑；利用理论与实验研究，比较基于不同电导率亚纳米腔下三明治结构的光学效应，进而揭示腔材料电导率对三明治结构光学耦合特性的影响规律；然后通过表面增强拉曼光谱（SERS）应用研究，为三明治结构构筑超灵敏SERS传感器奠定一定基础。本项目有利于丰富亚纳米腔的构筑，加深亚纳米腔下颗粒/膜光学耦合特性的认识，为发展新型金属等离子体光学传感器提供了新的技术保障。

金属纳米颗粒/二维材料光学系统因其独特的结构特性和超强的光学耦合特性获得了快速发展。本项目通过构筑金颗粒/硫化钼和金聚体/硫化钼光学耦合结构，在此基础上设计了金颗粒/硫化钼亚纳米腔/金膜结构光学耦合三明治结构，探索了金纳米单颗粒等离激元增强硫化钼光学吸收增强特性以及金聚体等离激元耦合下硫化钼光学吸收增强特性。通过与之前课题组开展的金颗粒/石墨烯亚纳米腔/金膜结构光学耦合结构光学吸收增强特性比较，揭示了二维材料电导率等材料特性对系统光学耦合特性的内在影响规律，阐明了不同硫化钼厚度与光学性能的对应关系。进一步扩展杂化结构，利用金属氧化物ZnO，设计得到了Au@MoS2-ZnO三元杂化结构，提升光学性能的同时，解决了二硫化钼光催化过程中的光腐蚀问题。本项目的开展加深等离激元增强二维材料光学耦合特性的认识，为发展新型金属等离激元光学器件提供新的技术保障。