Self-Assembly of Plasmonic Nanoclusters Mediated by Localized Steric Repulsion

1236309 PI：利用等离子体效应的新技术的实施在很大程度上取决于提高我们从纳米级金属构建块可靠和经济地生产复杂结构的能力。不幸的是，组织大量的纳米材料通过？自下而上可扩展的、成本有效的并且实现精确结构控制的策略仍然是有限的。本项目将研究一种新的策略，通过利用局部空间排斥和短程吸引，从纳米颗粒构建模块组装复杂结构。在这种新方法中，结构化簇的形成或将通过使用工程化纳米颗粒表面来控制，所述纳米颗粒表面含有末端接枝聚合物的混合物以调节空间排斥和小功能分子以诱导吸引。空间排斥和吸引力的相互作用将通过改变表面组成来精确地调节，以控制颗粒组装和操纵多颗粒结构的形态。使用这种稳健的策略，将产生具有可控的光学和电子特性的不同的胶体团簇。X射线和中子的小角散射将被用来选择性地探测纳米粒子的配置（SAXS）和构象的聚合物（SANS），以开发一个完整的和自洽的描述的组装过程。结构实验将通过与模拟的直接比较来补充。该项目的主要目标是：1）实验确定聚合物相互作用在介导纳米颗粒自组装中的作用2）减少自组装簇的结构多分散性3）用Monte Carlo模拟预测平衡簇结构和4）增加胶体分子的结构多样性。实现这些目标将大大有助于利用纳米粒子簇的等离子体应用的进步。等离子体激元技术利用可见光与小金属粒子中的离域电子云之间的独特相互作用。例如，等离子体效应用于开发用于快速识别复杂样品中痕量化学品和环境污染物的传感器。他们还推进了侵入性更小，更有效的医疗诊断和治疗工具，如光声成像和光热癌症治疗。等离子体激元方法还用于开发比当前技术更高效且更便宜的先进太阳能电池。尽管如此，这些和其他应用的成功部署需要在具有可控光学和电子特性的纳米结构的可扩展制造方面取得重大进展。该项目将研究一种新的方法，该方法适用于制造大量的等离子体纳米材料，同时保持精确的结构控制，并具有可扩展，鲁棒和通用的方法。

1236309PI: PozzoThe implementation of new technologies harnessing plasmonic effects depends strongly on improving our capacity to reliably and economically produce complex structures from nanoscale metallic building blocks. Unfortunately, the organization of large quantities of nanomaterials via ?bottom-up? strategies that are scalable, cost-effective and that achieve precise structure control is still limited. This project will research a new strategy to assemble complex structures from nanoparticle building blocks by exploiting local steric repulsion and short-ranged attraction. In this new approach, the formation of structured clusters or will be controlled through the use of engineered nanoparticle surfaces containing mixtures of end-grafted polymers to regulate steric repulsion and small functional molecules to induce attraction. Steric repulsion and attractive interactions will be precisely adjusted by altering the surface composition to control particle assembly and to manipulate the morphology of the multi-particle structures. Diverse colloidal clusters with controllable optical and electronic properties will be generated using this robust strategy. Small angle scattering of x-rays and neutrons will be used to selectively probe the nanoparticle configuration (SAXS) and the conformation of the polymers (SANS) in order to develop a complete and self-consistent description of the assembly process. Structural experiments will be complemented by direct comparisons to simulations. The primary goals of the project will be to: 1) Experimentally determine the role of polymer interactions in mediating nanoparticle self-assembly 2) Reduce the structural polydispersity of self-assembled clusters 3) Predict equilibrium cluster structures with Monte Carlo simulations and 4) Increase the structural diversity of colloidal molecules. Achieving these objectives will contribute significantly to the advancement of plasmonic applications that utilize nanoparticle clusters. Plasmonic technologies exploit the unique interactions between visible light and delocalized electron clouds in small metallic particles. For example, plasmonic effects are used to develop sensors for the rapid identification of trace amounts of chemicals and environmental contaminants in complex samples. They also advance less invasive and more effective medical diagnostic and treatments tools such as photoacoustic imaging and photothermal cancer therapy. Plasmonic approaches are also used to develop advanced solar cells that are more efficient and less expensive than current technologies. Nonetheless, the successful deployment of these and other applications requires significant advances in the scalable fabrication of nanostructures with controllable optical and electronic properties. This project will research a new approach that is suitable to fabricate large numbers of plasmonic nanomaterials while maintaining accurate structure control and with methods that are scalable, robust and versatile.