Unveiling the Clustering‐Triggered Emission Mechanism of Raffinose Aqueous Solution and Ion Detection

ABSTRACT Nonconventional luminophores, with tunable structure, good water solubility, and biocompatibility, show great application potential in encryption, bioimaging, and ion sensing. The intrinsic photoluminescence (PL) can be explained by the Clustering‐triggered emission (CTE) mechanism, yet general correlations between molecular structure, cluster architecture, and emission remain unclear. This study explored how concentration and pH affect raffinose's PL properties, revealing concentration‐enhanced emission and excitation dependence. Through in‐depth research on the emission mechanism of raffinose solution, it was found that the number and size distribution of clusters in the solution can be correlated with the emission capacity of the emission clusters. The dynamic light scattering (DLS) with particle size analysis and the conformational search of raffinose clusters further revealed the impact of molecular clusters on overall PL properties. Notably, the Fe 3 ⁺ fluorescence quenching effect on raffinose solutions is effectively utilized to detect Fe 3 ⁺ in aqueous solutions containing multiple metal ions, and this method has been applied to mixed metal ion detection. This research result not only successfully elucidates the relationship between the molecular structure, cluster's structure, and emission of raffinose, but also serves as a reference for intelligent luminescent materials.