Unprecedented stacking-dependent piezoluminescence enhancement in atomically precise superatomic gold nanoclusters

Deciphering the structure-property relationship between cluster stacking and high-efficiency luminescence of metal nanoclusters is crucial for designing and synthesizing high-performance light-emitting materials and devices. Here, we successfully synthesized two polymorphic gold nanoclusters (Au 8 -C and Au 8 -P) and investigated their stacking-dependent piezoluminescence based on hydrostatic pressure. Under compression, Au 8 -C exhibits notable piezoluminescence enhancement. However, Au 8 -P presents monotonic piezoluminescence quenching. High-pressure structural characterizations confirm the existence of stacking-dependent anisotropic compression in Au 8 -C and Au 8 -P. Under high pressure, the columnar-stacked Au 8 -C shrinks faster along the a axis, increasing the aspect ratio (AR) of the fusiform Au 8 core. However, the layered Au 8 -P is compressed faster along the c axis, reducing the AR and leading to a flatter Au 8 core. High-pressure femtosecond transient absorption, time-resolved photoluminescence, and Raman spectra collaboratively confirm that differentiated anisotropic compression notably suppresses nonradiative loss caused by low-frequency vibrations of the Au 8 core, which is responsible for the piezoluminescence enhancement in Au 8 -C.