基于飞秒时间分辨吸收和荧光光谱对发光金属纳米团簇激发态动力学的研究

Luminescent metal nanocluster (LMNC) is a recently developed interdisciplinary research field, closely related to physics, chemistry and nanoscience. LMNC’s size fills the gap between atom and nanomaterials. It has significant applications in scientific research and industry. Up to now, most of the studies in this field just emphasize on developing new synthetic methods and creating new LMNCs. The research on its luminescence mechanism is still in the initial stage. It is lack of reasonable theoretical explanation for many significant experimental phenomena. In this project, we will develop and apply various ultrafast time-resolved precision spectroscopy (femtosecond transient absorption, femtosecond resolved fluorescence based on frequency upconversion, picosecond resolved fluorescence based on time correlated single photon counting) to study the current debates and hot issues, which are as follows: 1. whether the origin of luminescence is metal-centered or ligand-centered; 2. aggregation-induced emission (AIE); 3. thermally activated delayed fluorescence(TADF).This research is expected to reveal the mechanism of these effects and their relationship with the metal and surface ligands, so as to guide the preparation of nanoclusters, the optimization of their performances, and their applications in sensitive bio-sensors. This study will give impetus to in-depth understanding of the luminescent nanoclusters, and promote the development of ultra-fast optics, cluster physics and related areas.

发光金属纳米团簇是近几年发展起来的一个与物理、化学、纳米紧密相关的全新交叉研究领域。它的尺寸介于原子级别与纳米级别之间，具有重要的科学研究意义和应用价值。到目前为止，此方面的研究侧重于发展新的合成方法，对其发光机理的研究尚处于初级阶段，对于很多重要实验现象还缺乏完善的理论解释。在本项目中，我们拟采用多种超快时间分辨精密光谱技术（飞秒瞬态吸收、基于频率上转换的飞秒时间分辨荧光、基于单光子计数的皮秒时间分辨荧光等）研究该领域现存的核心问题及研究热点，具体为：1、解答团簇发光中心究竟是内部金属核还是表面配体的争论；2、聚集诱导发光效应； 3、 热激活延迟荧光等。揭示这些效应的机理及其与金属和表面配体的关系，从而指导纳米团簇的制备和性能的优化，推动其在生物探针等高灵敏检测领域的应用。该研究将为我们全面认识和深入理解纳米团簇的发光本质起到巨大的推动作用，有力地推动超快光学、团簇物理等领域的发展。

发光金属纳米团簇是近几年发展起来的一个与物理、化学、纳米、环境等科学紧密相关的全新交叉研究领域。它的尺寸介于原子级别与纳米级别之间，具有重要的科学研究意义和应用价值。在本项目中，我们采用多种超快时间分辨精密光谱技术（飞秒瞬态吸收、基于频率上转换的飞秒时间分辨荧光、基于单光子计数的皮秒时间分辨荧光等）研究该领域现存的核心问题及研究热点，具体为：1、发展制备了多种新型发光金属纳米团簇；2.研究了一些新的物理化学现象，例如研究发光中心分别为内部金属核和表面配体为中心的两种团簇，研究了通过自组装可以导致寿命相差4个数量级的两种团簇状态等，揭示这些效应的机理；3.研究了新型纳米团簇在生物探针、环境科学等领域的应用；4.发展了新的时间分辨荧光光谱技术；在本项目中，我们按照预期计划开展了研究，达到了预期目标，取得了预期的研究成果。该项目的研究内容可以指导纳米团簇的制备和性能的优化，推动其在生物探针等高灵敏检测领域的应用，为我们全面认识和深入理解纳米团簇的发光本质起到巨大的推动作用，有力地推动超快光学、团簇物理等领域的发展。