Photoluminescence Quenching of Hydrophobic Ag₂₉ Nanoclusters Caused by Molecular Decoupling during Aqueous Phase Transfer and EmissionRecovery through Supramolecular Recoupling

Abstract

Exploiting emissive hydrophobic nanoclusters for hydrophilic applications remains challenging due to the photoluminescence (PL) quenching with the phase transfer. In addition, the underlying mechanism of such a PL quenching remains a mystery. The present study elucidated the PL quenching mechanism by analyzing the atomically precise structures and optical properties of a surface‐engineered Ag29 nanocluster with an all‐around‐carboxyl functionalized surface. Specifically, the phase transfer‐triggered PL quenching was justified as the molecular decoupling, which directed an unfixed cluster surface and the weakened radiative transition. Furthermore, the emission recovery of the quenched nanoclusters was accomplished via a supramolecular recoupling approach through the GSH addition‐induced aggregation of cluster molecules, wherein the restriction of intracluster motions and intercluster rotations strengthened the radiative transition of clusters. The findings in this work offer a new perspective on structure‐emission correlations for atomically precise nanoclusters, hopefully shedding light on the fabrication of more highly emissive cluster‐based nanomaterials aiming at downstream hydrophilic applications.