Self-Assembly of Plasmonic Nanoclusters Mediated by Localized Steric Repulsion

1236309PI：POZZO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积木可靠而经济地生产复杂结构的能力。不幸的是，通过自下而上的方式组织大量的纳米材料。可扩展、成本效益高、实现精确结构控制的战略仍然有限。该项目将研究一种新的策略，通过利用局部空间斥力和短程吸引，从纳米颗粒构建块组装复杂结构。在这一新方法中，将通过使用含有末端接枝聚合物的混合物的工程纳米颗粒表面来控制结构簇的形成，以调节空间斥力和诱导吸引的小功能分子。通过改变表面组成来控制粒子的组装和操纵多粒子结构的形态，可以精确地调节空间位阻和吸引相互作用。利用这一稳健的策略，将产生具有可控光学和电学性质的各种胶体团簇。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构型(SAXS)和聚合物(SANS)的构象，以便对组装过程进行完整和自洽的描述。结构实验将通过与模拟的直接比较来补充。该项目的主要目标将是：1)通过实验确定聚合物相互作用在纳米颗粒自组装中的作用；2)降低自组装团簇的结构多分散性；3)用蒙特卡罗模拟预测平衡团簇结构；4)增加胶体分子的结构多样性。实现这些目标将大大促进利用纳米粒子簇的等离子体应用的发展。等离子激元技术利用了可见光和小金属颗粒中离域电子云之间的独特相互作用。例如，等离子体效应被用来开发传感器，以快速识别复杂样品中的痕量化学品和环境污染物。他们还发展了侵入性更小、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。等离子体方法也被用来开发比当前技术更高效、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学特性的可伸缩制造纳米结构方面取得重大进展。本项目将研究一种新的方法，适用于制备大量等离子体纳米材料，同时保持精确的结构控制，并具有可伸缩性、健壮性和通用性。

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.