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。大块的黄金是金属的，不发光。然而，当它被分解成只有少量原子的微小团簇时，这样的金团簇就会发光。虽然这些发光的金簇是光稳定的，并且比许多半导体毒性更小，但它们的发光并不那么明亮。Guda博士和他的学生将致力于合理设计和合成具有更高量子效率和更广泛颜色的金簇。他们的发现可能导致纳米团簇用于光捕获和光学传感应用。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及其教师介绍纳米科学。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。实现高度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研究小组将合成金簇，增加簇表面金原子的刚性，目的是放大光致发光。金团簇的光学活性预计将进一步提高明智的功能化的表面与有机生色团，以实现有效的能量转移从表面结合的生色团到金团簇或反之亦然。超快时间分辨吸收和光致发光技术的组合将被用来解开这些混合结构中的激发态弛豫机制，并提供反馈，以设计具有增强的光学活性的簇。该机制的研究有望揭示内在的能量和电荷转移之间的相互作用发色团和原子精确的金簇。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

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.