Cross-Linkable Room-Temperature Phosphorescent Polymer Blends With Ultrawide Modulus Tunability

Pure organic room-temperature phosphorescence (RTP) polymers have attracted considerable attention for their promising applications in information encryption, anti-counterfeiting, and flexible optoelectronics. Herein, we report a strategy combining physical blending and in situ covalent cross-linking to fabricate processable RTP polymer blends with ultrawide mechanical tunability. Flowable precursors are first prepared by dispersing carbazole-based phosphor-doped polystyrene (PS) into polyethylene glycol (PEG), followed by cross-linking of terminal hydroxyl groups to form a three-dimensional polyurethane network that provides an excellent oxygen barrier and shape fixation. The optimized system exhibits bright yellow RTP with afterglow durations of 1.7-5.5 s, representing a 2-5-fold enhancement compared with non-cross-linked systems. Impressively, Young's modulus can be precisely tuned over 9 orders of magnitude from ∼10^-1 to ∼10⁸ Pa. This work provides a universal and scalable route for developing moldable, mechanics-tunable RTP polymers for advanced optical and anti-counterfeiting applications.