Cooperative Action of Light and Surfactants in Plasmon-Driven Anisotropic Growth of Silver Nanostructures

金属纳米颗粒可以以各种不同的形状产生。这些小粒子中松散的电子可以被光推动，像水池中的波浪一样四处晃动。随着光强度的增加，这些波（称为等离子体）变得更大，并且有足够的能量，它们可以引起化学反应。 粒子的形状也会影响等离子体波的大小，角落产生的波比粒子的其他部分更大。 因此，需要具有尖锐特征的颗粒。创造这些复杂结构的一个策略是使用光来促进生长。问题是，这些尖锐特征形成的机制尚不清楚，因此难以控制。在化学系大分子、超分子和纳米化学（MSN）项目的支持下，佛罗里达大学的魏大卫魏教授正在探索具有棱柱形状的银纳米结构的光驱动生长。 从该项目中获得的见解可能会导致新材料的产生，从而推进从癌症治疗到太阳能转换的技术。 该项目还为下一代科学家提供培训机会，并对高中学生，教师和公众进行等离子体纳米材料的教育。 魏教授还计划开发西班牙语的无线电模块，将普通科学带给佛罗里达科学界历史上代表性不足的群体。 魏教授和他的学生们正在探索表面等离子体共振（SPR）在驱动Ag纳米棱镜生长中的作用。该过程从球形Ag纳米颗粒开始，然后将其暴露于强光源。 然后，研究小组使用透射电子显微镜（TEM）方法和电子能量损失谱（EELS）观察粒子的生长，计算机模拟有助于解释实验数据。 在单纳米粒子水平的观察提供了一个详细的视图的基础物理和化学过程调节等离子体驱动的合成的银纳米棱镜。 该项目正在探索表面活性剂和金属SPR之间的合作相互作用的重要性，以有效地利用等离子体驱动的光化学合成纳米材料。该项目中获得的分子水平的见解不仅为设计和构建其他类型的形状控制等离子体纳米结构奠定了基础，更重要的是，该奖项反映了美国国家科学基金会的法定使命，并被认为值得通过利用基金会的知识价值和更广泛的影响审查进行评估来支持的搜索.

Metallic nanoparticles can be created in a variety of different shapes. The loosely held electrons in these small particles, which can be pushed around by light, slosh around like waves in a pool. As the light intensity increases, these waves (called plasmons) become bigger, and with enough energy they can cause chemical reactions. The particle's shape can also affect the size of the plasmon waves, with corners creating bigger waves than other parts of the particle. As a result, particles with sharp features are desired. One strategy for creating these complicated structures is to use light to promote the growth. The problem is that the mechanism by which these sharp features form is not understood, and therefore difficult to control. With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry, Professor Wei David Wei at the University of Florida is exploring the light-driven growth of Ag nanostructures with prismatic shapes. Insights gained from the project could lead to new materials, advancing technologies that range from cancer therapies to solar energy conversion. The project is also providing training opportunities for the next generation of scientists, as well as educating high school students, teachers, and the general public on plasmonic nanomaterials. Professor Wei also plans to develop radio modules in Spanish to bring general science to groups historically underrepresented in the scientific community in Florida. Working with his students, Professor Wei is exploring the role of the surface plasmon resonance (SPR) in driving the growth of Ag nanoprisms. The process starts with spherical Ag nanoparticles, which are then exposed to an intense light source. The team then watches the particle grow using transmission electron microscopy (TEM) methods and electron energy loss spectroscopy (EELS), and computer simulations aid in the interpretation of the experimental data. Observations at the single-nanoparticle level provide a detailed view of the underlying photophysical and chemical processes regulating the plasmon-driven synthesis of the Ag nanoprisms. The project is exploring the importance of a cooperative interplay between surfactants and metal SPR to effectively harness plasmon-driven photochemistry for nanomaterials synthesis. The molecular-level insights obtained in this project not only lay the groundwork for the design and construction of other types of shape-controlled plasmonic nanostructures, but more importantly, their implications benefit a broader field of plasmonic photochemistry beyond nanomaterials synthesis.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.