Construction of Cross‐Linked Polymer Phosphorescence by Functionalization of Cyclotriphosphazene

Abstract In recent years, organic room‐temperature phosphorescence (RTP) materials have garnered significant research interest. However, the design and synthesis of novel polymeric RTP systems continue to pose substantial challenges. By leveraging cyclotriphosphazene functionalization, four novel phosphors are successfully developed. The presence of numerous heteroatoms (O, N, P) within this structure significantly enhances molecular spin‐orbit coupling (SOC). Initially, the incorporation of these novel phosphors into a polyvinyl alcohol (PVA) matrix yielded only weak RTP emissions. Remarkably, thermal annealing transformed these materials into long‐lived cross‐linked polymer RTP films. Specifically, a representative luminescent film (THMD@PVA) exhibits enhancements in phosphorescence intensity, lifetime, afterglow brightness, and quantum yield by factors of 8, 4, 18, and 6, respectively. With superior mechanical and luminescence properties, these RTP materials are well‐suited for creating flexible and reconfigurable 3D objects. Furthermore, the dual luminescence of fluorescent and phosphorescent emissions expands their applicability, including fingerprint recording, thereby broadening the application scope of organic RTP materials.