Abstract
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.