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 a challenge because of photoluminescence (PL) quenching during phase transfer. In addition, the mechanism underlying PL quenching remains unclear. In this study, the PL‐quenching mechanism was examined by analyzing the atomically precise structures and optical properties of a surface‐engineered Ag 29 nanocluster with an all‐around‐carboxyl‐functionalized surface. Specifically, phase‐transfer‐triggered PL quenching was justified as molecular decoupling, which directed an unfixed cluster surface and weakened the radiative transition. Furthermore, emission recovery of the quenched nanoclusters was accomplished by using a supramolecular recoupling approach through the glutathione‐addition‐induced aggregation of cluster molecules, wherein the restriction of intracluster motion and intercluster rotation strengthened the radiative transition of the clusters. The results of this work offer a new perspective on structure‐emission correlations for atomically precise nanoclusters and hopefully provide insight into the fabrication of highly emissive cluster‐based nanomaterials for downstream hydrophilic applications.