Coherent Strategies to Achieve Luminescent Gold Clusters for Photonic Applications

在化学系大分子、超分子和纳米化学(MSN)计划的支持下，西密歇根大学的Ramakrishna Guda正在努力创造用于光学应用的高发光金纳米团簇。在大件中，黄金是金属的，不发光。然而，当它被分解成原子数量较少的微小星团时，这样的金星团就会发光。虽然这些发光的金团簇具有光稳定性，而且毒性比许多半导体小，但它们的发光并不那么明亮。古达博士和他的学生将致力于合理地设计和合成金簇，这种发光具有更高的量子效率和广泛的颜色范围。他们的发现可能导致纳米团簇用于光采集和光学传感应用。该项目还将为研究生和本科生提供研究机会，并通过教育研讨会向高中生和他们的老师介绍纳米科学。原子精确的量子尺寸的金纳米团簇提供离散的电子态、独特的光致发光和独特的激发态弛豫，使它们成为各种光子应用的理想候选者。获得高发光的金纳米团簇是具有挑战性的，并且阻碍了它们作为光子材料的进展。Guda研究团队将通过增加团簇表面金原子的刚性来合成金团簇，目标是放大光致发光。金团簇的光学活性有望通过明智地用有机生色团对表面进行官能化来实现从表面发色团到金团簇的有效能量转移，反之亦然。超快时间分辨吸收和光致发光技术的结合将被用来揭示这些混合结构中激发态弛豫的机制，并为设计具有增强光学活性的团簇提供反馈。这些机制研究有望揭示发色团和原子精确的金簇之间的内在能量和电荷转移相互作用。这一奖项反映了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。

With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program in the Division of Chemistry, Ramakrishna Guda of Western Michigan University is working to create highly luminescent gold nanoclusters for optical applications. In large pieces, gold is metallic and does not emit light. However, when it is broken down to tiny clusters with only a smaller number of atoms, such gold cluster will emit light. While these luminescent gold clusters are photostable and less toxic than many semiconductors, their luminescence is not as bright. Dr. Guda and his students will work to rationally design and synthesize gold clusters that luminescence with greater quantum efficiencies and over a broad range of colors. Their discoveries could lead to nanoclusters for light harvesting and optical sensing applications. The project will also provide research opportunities for graduate and undergraduate students, as well as introduce nanoscience to high school students and their teachers through education workshops. Atomically precise quantum-sized gold nanoclusters offer discrete electronic states, distinctive photoluminescence and exclusive excited-state relaxation that make them ideal candidates for various photonic applications. Achieving highly luminescent gold nanoclusters is challenging and is impeding their progress as photonic materials. The Guda research team will synthesize gold clusters with increased the rigidity of gold atoms at the cluster surface, with the goal of amplifying photoluminescence. The optical activity of gold clusters is expected to be further improved by judiciously functionalizing the surface with organic chromophores to achieve efficient energy transfer from a surface-bound chromophore to gold cluster or vice-versa. A combination of ultrafast time-resolved absorption and photoluminescence techniques will be used to unravel the mechanism of excited-state relaxation in these hybrid structures and provide feedback to design clusters with enhanced optical activity. The mechanistic studies are expected to shed light on intrinsic energy and charge transfer interactions between chromophores and atomically precise gold clusters.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.