CAREER: Tuning optical responses in artificial molecules of monovalent gold nanocrystals

职业：调节单价金纳米晶体人造分子的光学响应

• 批准号: 1351663
• 负责人: Ming Tang
• 金额: $ 65万
• 依托单位: University of California-Riverside
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-05-01 至 2019-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1351663&HistoricalAwards=false
• 关键词: CAREER; Tuning; optical; responses; artificial

Ming L. Tang of the University of California Riverside is supported by the Macromolecular, Supramolecular and Nanochemistry program in a CAREER award to link nanoparticles together in uniquely well-defined ways. Nanoparticles made of gold and other noble metals can exhibit surface plasmon modes that are particularly effective at absorbing or scattering light in specific regions of the visible spectrum. This research is to hook them together in selective ways, the goal being to expand our ability to control interactions of light with matter at the nanoscale level. The approach is by chemical means, so that one can readily scale up the synthesis of these assemblies. The education component of this CAREER project is to deliver to the greater public the excitement of the fascinating properties of plasmonic nanoparticles. It includes the creation of a nanomaterials-focused, discovery-based laboratory course, "Painting with Plasmons and Polymers," for first year undergraduate students. This represents a new addition to the University of California Riverside's (UCR's) Learning Community program, which has been shown to increase retention rates of STEM majors and push 4-year graduation rates from 24% to 40%. First year student leaders from this class are expected to engage local middle and high school students with scientific demonstrations and to inspire them with stories about their personal path towards a STEM degree. The PI mentors students and teachers from these schools by providing them an opportunity to work in her research laboratory along with graduate students and undergraduates.The goal of controlling nanoscale light-matter interactions in nanoparticle assemblies is achieved by inducing strong electric and magnetic transitions, particularly the latter, which are especially weak in the visible frequencies. Supra-molecular chemistry and solid phase synthesis is being used to create "monovalent gold" building blocks, i.e., gold nanoparticles each with a single binding site, as a powerful alternative to the current state of the art DNA-based self-assembly. The self-assembly method aims to control particles from 5-100 nm in size and to engineer inter-particle distances on the order of 1-20 nm. First, precise control over the distance between two nanoparticles of different composition creates heterodimers employed to identify modes disallowed by symmetry arguments. Second, by virtue of an inter-particle geometry dictated by a molecular scaffold, both electric and magnetic dipoles are induced in the circulating currents within the artificial molecule. Strong, tunable magnetic dipoles allow introduction of Fano resonances with high quality factors that are useful for sensing. And third, 3-D tetrahedral constructs with core-shell nanoparticles predicted to have overlapping electric and magnetic dipoles are being investigated.

加州大学河滨分校的 Ming L. Tang 获得了大分子、超分子和纳米化学项目的职业奖支持，以独特的明确方式将纳米颗粒连接在一起。由金和其他贵金属制成的纳米颗粒可以表现出表面等离子体激元模式，该模式在吸收或散射可见光谱特定区域的光方面特别有效。 这项研究是以选择性的方式将它们连接在一起，目标是扩大我们在纳米级水平上控制光与物质相互作用的能力。该方法是通过化学手段进行的，因此人们可以轻松地扩大这些组件的合成规模。该职业项目的教育部分是向更多公众传递等离激元纳米颗粒迷人特性的兴奋感。它包括为一年级本科生创建一门以纳米材料为重点、以发现为基础的实验室课程“等离激元和聚合物绘画”。这是加州大学河滨分校 (UCR) 学习社区计划的新成员，该计划已被证明可以提高 STEM 专业的保留率，并将 4 年毕业率从 24% 提高到 40%。该班一年级的学生领袖预计将通过科学演示吸引当地中学生和高中生，并通过讲述个人通往 STEM 学位之路的故事来激励他们。 PI 为这些学校的学生和教师提供指导，为他们提供与研究生和本科生一起在她的研究实验室工作的机会。控制纳米颗粒组件中纳米级光与物质相互作用的目标是通过诱导强电和磁转变来实现的，特别是后者在可见光频率特别弱。超分子化学和固相合成被用来创建“单价金”构建块，即每个都具有单个结合位点的金纳米颗粒，作为当前最先进的基于 DNA 的自组装的强大替代方案。自组装方法旨在控制尺寸为 5-100 nm 的颗粒，并将颗粒间距离设计为 1-20 nm 数量级。首先，精确控制两个不同组成的纳米颗粒之间的距离会产生异二聚体，用于识别对称性论证所不允许的模式。其次，凭借分子支架决定的颗粒间几何形状，在人造分子内的循环电流中感应出电偶极子和磁偶极子。强大的可调谐磁偶极子可以引入具有高品质因数的法诺共振，这对传感很有用。第三，正在研究具有核壳纳米颗粒的 3D 四面体结构，预计具有重叠的电偶极子和磁偶极子。