Controlled modulation of the specific crystal surfaces is vital in nanotechnology but remains challenging to implement. Here, we achieve sequential vertex modulation in atomically precise homochiral silver nanoclusters using a scalable crystallization synthesis. By tuning the reductant conditions, we generate mixed-phase cocrystallized R/S-Ag19·Ag20 comprising enantiopure R/S-Ag19 and R/S-Ag20, featuring the first icosahedral Ag13 core with 6 electrons. Using kinetic and thermodynamic control, we sequentially add Ag atoms to the cubic facets, progressing from the Ag6 shell in R/S-Ag19 (two missing vertices) to the Ag7 shell in R/S-Ag20 (one missing vertex), and ultimately to the closed Ag8 shell in R/S-Ag21, and luminescence is induced. This geometric evolution is reminiscent of the arachno → nido → closo transformations in borane clusters, where vertex recovery leads to increasingly close polyhedral frameworks. Shell closure results in 2e filling, symmetry adaptation and chirality mutation. Additionally, R/S-Ag21 enables quantitative chiral sensing of amino acids. This work advances nanosynthesis by providing a framework for controlling surface modulation and fine-tuning the nanocluster properties and can be used to facilitate the development of improved functional (chiral) nanomaterials.
Kong et al. (2026) studied this question.