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Collaborative Research: Optical Transitions in Metallic Nanoclusters at High Pressure

合作研究：高压下金属纳米团簇的光学跃迁

基本信息

批准号：
2002936
负责人：
Xun Wendy Gu
金额：
$ 37.5万
依托单位：
Stanford University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2025-06-30
项目状态：
未结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2002936&HistoricalAwards=false
关键词：
Collaborative Research Optical Transitions Metallic

项目摘要

NONTECHNICAL SUMMARYThis research program contributes to innovations in nanomaterials that are useful in biomedical therapies, sensing, and catalysis. Nanoclusters that consist of fewer than ~200 metallic atoms are of interest due to their luminescence in near-infrared light, bio-compatibility and ultra-small size. The relationship between the structure and optical properties of these nanoclusters remains unclear, which prevents the design of nanoclusters with optimized performance. This program uses pressure to modify the structure of nanoclusters, in order to learn about the electronic transitions that are responsible for light absorption and luminescence, as well as the stability of nanoclusters under external stimulus. This research is closely tied to our educational plans through the training of postdocs and graduate students, by supporting underrepresented groups at the K-12 and college level in science and technology, and by supporting science teachers in the community. In addition, modules that explain the influence of mechanics on optical behavior will be incorporated into undergraduate courses during this program.TECHNICAL SUMMARYThe proposed research is concerned with characterizing the properties of atomically precise clusters composed of gold or silver plus ligands using diamond anvil cell techniques to apply high pressure, and with optical measurements (both absorption and emission) to study excited states. The experiments will be modeled using electronic structure theory, including ground state calculations to determine structures, and excited state studies to determine optical properties, and including methods development based on second linear response theory and domain-separated density functional theory. The research is aimed at identifying optical properties such as plasmon to exciton transitions, and an increase in luminescence efficiency with increasing pressure; both properties are of interest to using the clusters in practical applications. The research includes three research objectives: (1) study of energy transfer responsible for broad absorption & near-infrared luminescence of the cluster material under pressure, (2) determine the source of anomalous multiple emissions of the nanoclusters, and (3) studies of 2-3 nm nanoclusters to characterize the transition from plasmonic to excitonic states.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.

非技术性总结这项研究计划有助于在生物医学治疗，传感和催化有用的纳米材料的创新。由少于~200个金属原子组成的纳米团簇由于其在近红外光下的发光、生物相容性和超小尺寸而引起人们的兴趣。这些纳米团簇的结构和光学性质之间的关系仍然不清楚，这妨碍了具有优化性能的纳米团簇的设计。该计划利用压力来改变纳米团簇的结构，以了解负责光吸收和发光的电子跃迁，以及纳米团簇在外部刺激下的稳定性。这项研究与我们的教育计划密切相关，通过培养博士后和研究生，支持K-12和大学一级的科学和技术代表性不足的群体，并支持社区的科学教师。此外，模块，解释力学对光学行为的影响将被纳入本科课程在此计划。技术摘要拟议的研究是关注的性质的原子精确的集群组成的金或银加上配体使用金刚石砧室技术施加高压，并与光学测量（吸收和发射）研究激发态。实验将使用电子结构理论建模，包括基态计算以确定结构，激发态研究以确定光学性质，并包括基于第二线性响应理论和域分离密度泛函理论的方法开发。该研究旨在确定光学性质，如等离子体激元到激子的跃迁，以及随着压力的增加而增加的发光效率;这两种性质都对在实际应用中使用簇感兴趣。该研究包括三个研究目标：（1）研究团簇材料在压力下的宽吸收近红外发光的能量转移，（2）确定纳米团簇异常多重发射的来源，（3）研究2-3 nm纳米团簇以表征从等离子体到激子态的转变。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。