Achieving Efficient Blue Room‐Temperature Phosphorescence Through Self‐Doping of Similar Structures and Polymer Assistance

Abstract Blue is one of the three primary colors, and it is a crucial element in the regulation and application of organic room‐temperature phosphorescence (ORTP). However, the considerable Stokes shift of small organic molecules presents a challenge for creating blue afterglow materials. To address this, host‐guest‐doped materials are prepared by selecting compounds with similar structures for self‐doping. This method effectively regulated blue organic long‐lasting phosphorescence. Additionally, the persistent‐RTP and organic long‐persistent luminescence (LPL) properties can be further enhanced by incorporating a rigid or flexible polymer network, creating a dense environment between the host and guest. Remarkably, the phosphorescence lifetime and afterglow duration of polymer‐assisted doped materials are ≈5 times greater than those of host‐guest doped crystal materials. Apart from its high efficiency, environmental friendliness, and easy synthesis, this blue ORTP material boasts high thermal stability and flexibility. Furthermore, this blue material demonstrates considerable potential in applications such as information encryption and anti‐counterfeiting across various media, including paper, cotton thread, and leaves.