High-Pressure Fabrication of Atomically Precise Chiral Silver Nanoclusters with High Luminescence Efficiency

High-pressure reversibility is a predominant challenge restricting the practical application of hydrostatic pressure in high-pressure synthesis. Herein, we have successfully preserved the high-pressure metastable phase of an atomically precise chiral silver nanocluster {[Ag8H(D/L-dtp)6(PPh3)2](CF3COO); (D/L-Ag8)} with a high quantum yield (QY) under ambient conditions based on pressure-enhanced argentophilic interactions. D/L-dtp and PPh3 represent (D/L)-o,o′-di[2-isopropyl-5-methylcyclohex-1-yl]dithiophosphoric acid and triphenylphosphine ligands, respectively. Initially, D/L-Ag8 exhibits low-quality red circularly polarized luminescence (CPL). Under compression, D/L-Ag8 presents a substantially enhanced piezoluminescence. At 2.3 GPa, the QY of D/L-Ag8 is boosted from an initial 2.4% to a maximum of 70.5%. Notably, the pressure-amplified QY (21.5%) of D/L-Ag8 is preserved even after the pressure is released. The single-crystal X-ray diffraction results reveal that the D/L-Ag8 kernel comprises a seven-nucleus silver polyhedron (Ag7) and an independent silver atom (Ag8). High-pressure structural characterization and theoretical calculations demonstrate that pressure induces the contraction of interatomic distances, triggering additional argentophilic interactions between Ag7 and Ag8. In situ high-pressure femtosecond transient absorption combined with Raman spectra further confirms that pressure-enhanced argentophilic interactions significantly suppress nonradiative energy dissipation caused by the disordered vibration of Ag atoms through strengthening the structural rigidity of the D/L-Ag8 core. This is responsible for the enhancement of piezoluminescence and the pressure-trapped efficient QY of D/L-Ag8. Our work opens a novel avenue for preparing high-performance chiral materials via high pressure without changing the chemical composition.