Appropriately Rigid Ionic Confinement for Dynamic Organic Room-Temperature Phosphorescence via Triplet Exciton Competition
Room-temperature phosphorescence (RTP) has attracted substantial interest for applications in smart optoelectronics, yet the development of dynamic RTP systems remains intrinsically challenging. Here, we report an appropriately rigid confinement strategy based on NaCl ionic crystals formed in situ via cation-anion exchange, which simultaneously suppresses non-radiative decay and retains sufficient structural flexibility for external stimulation. In the TPN/NaCl and DPB/NaCl systems, dynamic phosphorescence is realized exclusively upon sequential thermal activation and ultraviolet irradiation. Mechanistic investigations reveal that residual water and triplet oxygen initially quench triplet excitons, and their gradual removal enables a competitive evolution between triplet-triplet annihilation (TTA) and phosphorescence pathways. This work establishes a general design principle for constructing stimulus-responsive dynamic RTP systems and resolves the long-standing conflict between rigidity and responsiveness in organic phosphorescent materials.