Robust Ultra‐high Phosphorescence Brightness from Phenyl(triphenylen‐2‐yl)methanone Derivatives Doped Non‐polar Polymers

Comprehensive Summary Developing persistent room temperature phosphorescence (RTP) materials with ultra‐bright afterglow has been a great challenge. Most organic RTP systems emitted dim afterglow, which is only visible in dark environments. Herein, we reported a robust ultra‐high afterglow brightness system by doping a type of phenyl(triphenylen‐2‐yl)methanone (TpP) derivatives into a non‐polar polymeric matrix, styrene‐ethylene butylene‐styrene (SEBS). The strong π‐π interaction between TpP emitters and SEBS, combined with their suitable energy levels, ensured that the doped materials exhibited persistent phosphorescence with an extraordinarily bright afterglow, reaching values up to 6.0 cd/m 2 . Such a high afterglow was just slightly reduced to 2.3 cd/m 2 , even at a high temperature of 353 K. Their afterglow can even be clearly observed under sunlight. Further comparative studies revealed that the phenyl carbonyl unit in these TpP‐type compounds is also a crucial factor, significantly enhancing the efficiency of the intersystem crossing. Additionally, the bright afterglow demonstrated excellent resistance to UV light and oxygen, ascribed to the inherent properties of the SEBS matrix itself. Therefore, this work provides an effective design strategy for the preparation of organic afterglow materials with high brightness and persistent emission.