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

金属纳米粒子可以被创造成各种不同的形状。在这些可以被光推动的小颗粒中，松散地持有的电子就像池子里的波一样四处晃动。随着光强的增加，这些波(称为等离子激元)会变得更大，有了足够的能量，它们就可以引起化学反应。粒子的形状也会影响等离子激元波的大小，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粒子。创造这些复杂结构的一种策略是利用光来促进生长。问题是，这些尖锐特征形成的机制还不清楚，因此很难控制。在化学系大分子、超分子和纳米化学(MSN)计划的支持下，佛罗里达大学的魏大卫教授正在探索光驱动生长棱柱状银纳米结构。从该项目中获得的见解可能会带来新材料，推动从癌症疗法到太阳能转换等一系列技术的进步。该项目还为下一代科学家提供了培训机会，并对高中生、教师和普通公众进行了等离子纳米材料的教育。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州科学界历史上代表性不足的群体。魏教授正在与他的学生一起探索表面等离子体共振(SPR)在驱动银纳米管生长中的作用。这一过程首先是球形的银纳米颗粒，然后将其暴露在强烈的光源下。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。在单纳米颗粒水平上的观察提供了调控等离子体驱动的银纳米管合成的基本光物理和化学过程的详细视图。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来合成纳米材料。在这个项目中获得的分子水平的见解不仅为其他类型的形状控制等离子体纳米结构的设计和建造奠定了基础，更重要的是，它们的影响使等离子体光化学的更广泛领域受益于纳米材料合成。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

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.