Dynamic Phosphorescence Behavior of Carbene‐Metal‐Amide Complexes from the Perspective of Excited State Modulation
Xiang-Ming Zeng, Minjian Wu, Liao‐Yuan Yao, Guo‐Yu Yang
Abstract
Abstract Carbene‐metal‐amide (CMA) complexes have diverse applications in luminescence, imaging and sensing. In this study, we designed and synthesized a series of CMA complexes, which were subsequently doped into a PMMA host. These materials demonstrate light‐induced dynamic phosphorescence, attributed to their long intrinsic triplet state lifetime ( τ P ,int , in the μs‐ms scale), high intersystem crossing (ISC) rate constant ( k ISC , up to 10 7 s −1 ), and bright phosphorescence. The extended τ P ,int , and elevated k ISC facilitate efficient sensitization of singlet oxygen ( 1 O 2 ) under light irradiation, which is rapidly consumed by the host material, creating a localized anaerobic environment conducive to bright phosphorescence emission. The S n ‐T 1 process exhibits a large spin‐orbital coupling matrix element (SOCME) value, while the SOCME value between T 1 and S 0 is comparatively smaller, resulting in a large k ISC and long τ P ,int , Computational results indicate that the hole‐electron configuration in the lowest triplet state exhibits low contributions from gold. Based on the dynamic phosphorescence properties, an encryption material capable of achieving a “burn after reading” effect was developed. This work illustrates that those phosphorescent emitters with minimal heavy atom contribution can produce dynamic phosphorescent phenomena, providing a novel strategy for designing stimuli‐responsive phosphorescent materials.