光功能导向的新型贵金属纳米结构的设计及可控制备

A considerable attention from many fields, including physics, material science, energy and biomedical science, has been attracted to the study of noble metal nanostructures due to their unique optical properties oriented from the surface plasmon resonance (SPR). Contrast to the explosion of plasmonic nanoparticle monomer, more attention was paid on the hollow nanoframe, multilayer nanostructures and assembly system for their more excellent coupling effect surface plasma resonance and corresponding potentials. Based on our previous research on the shape-controlled noble metal nanostructures, the following related research items will be involved in this project. 1) Experimentally, novel-shaped nanostructures enriched with nanogaps and tunable optical properties, involving core/shell nanostructure, nanocavity and multilayer nanostructure, will be fabricated based on the as-prepared isolated high-purity noble metal nanoparticles (such as nanobipyramids and ultrafine nanorods). The problems of lattice mismatch on heterogeneous structure over-growth will be solved by optimizing experimental parameters. 2) The growth mechanism and some essential problems of SPR effects, such as charge distribution and resonance energy transfer of localized field, tailoring the resonance line-shape with Fano resonance, multi SPR coupling and some new possible resonance modes, will be discussed through first-principles calculation, finite difference time domain (FDTD) simulation and surface plasmon hybridization. 3) Study on the correlation between optical properties and novel nanostructures will be carried out through combing theory analysis with experimental results. Some problems, such as photoelectric interaction and thermodynamics physics of localized field coupling effect in the nanogap and nanocavity will be analyzed by optical characterizations and especially near field optical measurements. The application mechanism of SPR effects on catalysis and surface enhanced Raman scattering will also be discussed. Through the research of these closed related items, we aim to realize the fabrication of metallic nanostructures with tunable optical properties and establish the structure-relationship for the optical responses. And then make clear some essential problems about SPR optical effects, such as multipole resonance coupling, distribution and transfer of charge and resonance energy in plasmonic nanostructure systems. The project is also aimed at exploiting and further designing novel nanostructures and functional units enriched with strong localized field, many “hot” spots, and high SPR quality factor for the potentials in hypersensitive plasmonic sensors and molecular devices fields.

贵金属纳米结构表面等离激元共振（SPR）光学效应已引起物理、材料、生物医学等领域的广泛关注，其中，空腔、组装体等新型纳米结构呈现更加优异的光学效应和应用前景。本项目拟开展：1）制备高纯度金属纳米颗粒（如纳米双锥），构筑核-壳结构、纳米双锥尖-尖组装、空腔和嵌套等新型纳米结构，解决异质结构生长中的晶格失配问题，实现光学性质调控；2）利用第一性原理、FDTD模拟和等离激元杂化理论，研究纳米结构的形成机制、耦合效应对谱线的整形、多极SPR耦合过程中的电荷分布及能量转移等；3）研究新型纳米结构光学性质与结构的相关性，阐述纳米间隙和纳米空腔局域场增强效应中光-电-热物理问题及SPR对催化和SERS特性的影响。本项目旨在通过构筑新型纳米结构，实现光功能可调控，利用耦合对谱线的整形，设计出强场、高SPR品质因子的新型纳米结构与功能化单元，为材料在能量转换、传感等领域的应用提供功能化单元和研究基础。

本项目开展富含纳米间隙和空腔的新型金属纳米结构的可控制备及其SPR效应研究。项目完成了项目预期目标，具体内容、结果和科学意义如下：. 1）新型纳米结构的可控制备和性质研究。以高纯度金纳米双锥和纳米棒为基础，设计实验方案，探索出了制备多孔合金、空腔和嵌套等新型纳米结构最佳实验条件，实现所得纳米结构的光学性质可调性。利用第一性原理、FDTD模拟和等离激元杂化理论，研究结构生长机制、空腔结构的耦合效应。研究了新型纳米结构性能与结构的相关性，阐述了纳米间隙和纳米空腔局域场增强效应中光-电-热多场耦合问题及SPR效应对催化和SERS特性的影响。. 2）新型纳米结构的应用研究。合金纳米棒化学和热稳定性高，且在500-2000nm范围具有可调制强吸收效应，在隐身涂层方面具有应用前景；探索了纳米结构在催化、传感、分子担载与释放方面的应用，表现出优秀的催化活性和传感特性，介孔SiO2包覆形成的空腔结构不仅具有生物兼容性，而且光热效应能够促进药物释放。. 3）等离激元热电子效应在光电器件中的应用研究。将贵金属纳米颗粒、纳米线、核-壳纳米结构、合金纳米结构应用于调制半导体光电器件的性能，阐明了等离激元热电子效应对光电器件的调制机理，实现了蓝光-绿光-黄光-红光微小灯丝光源及发光强度与波长的调制。将超细银铜纳米线制备成兼有透明导电和电磁屏蔽功能的柔性薄膜，并用于器件的电极材料。贵金属纳米结构在光电器件性能调制中展现重要的应用价值。. 相关研究成果在Photonics Research、Nanoscale、Advanced Optical Materials、Journal of Materials Science & Technology等期刊发表学术论文50多篇，多项成果以封面论文的形式发表，并在学校新闻网、工信部网站做亮点报道及杂志网站推送；相关材料制备和器件构筑方法申请专利15项。基于研究成果，申请人获得第六届江苏省光学学会青年光学科技奖。