A comprehensive understanding of excited-state dynamics of semiconductor quantum dots or nanomaterials at the atomic or molecular level is of scientific importance. Pure inorganic (or non-covalently protected) seimiconductor molecular nanoclusters with atomically precise structure are contributive to establish accurate correlation of excited-state dynamics with their composition/structure, however, the related studies are almost blank because of unresolved solvent dispersion issue. Herein, we designedly created the largest discrete chalcogenide seimiconductor molecular nanoclusters (denoted P2-CuMSnS, M = In or/and Ga) with great dispersibility, and revealed an interesting intracluster “core-shell” charge transfer relaxation dynamics. A systematic red shift in absorption spectra with the gradual substitution of In by Ga was experimentally and computationally investigated, and femtosecond transient absorption measurements further manifested there were three ultrafast processes in excited-state dynamics of P2 nanoclusters with the corresponding amplitudes directed by composition variation. Current results hold the great promise of the solution-processible applications of semiconductor-NC-based quantum dots and facilitate the development of atomically precise nano-chemistry.

在原子或分子水平上全面理解半导体量子点或纳米材料的激发态动力学具有科学重要性。具有原子精确结构的纯无机（或非共价保护）半导体分子纳米团簇有助于建立激发态动力学与其组成/结构的精确关联，但是，由于未解决的溶剂分散问题，相关研究几乎是空白。本文中，我们设计了具有最大分散性的最大离散硫族化物半导体分子纳米簇（表示为P2-CuMSnS，M = In或/和Ga），并揭示了有趣的簇内“核-壳”电荷转移弛豫动力学。通过实验和计算研究了In逐渐被Ga取代In时吸收光谱的系统红移，飞秒瞬态吸收测量进一步表明P2纳米团簇的激发态动力学中存在三个超快过程，其相应振幅由成分变化决定。当前的结果为基于半导体-NC的量子点的可解决性应用的发展带来了广阔的前景，并促进了原子精确的纳米化学的发展。