Dynamic Transition between Monomer and Excimer Phosphorescence in Organic Near‐Infrared Phosphorescent Crystals

• DOI: 10.1002/adma.202311384
• Publication Date: 2024-01-05T06:34:55Z
• Authors: Zihao Deng; Jianyu Zhang; Jiaming Zhou; Wei Shen; Yunfei Zuo; Jin Wang; Shengyi Yang; Junkai Liu; Yuyang Chen; Chun‐Chao Chen; Guocheng Jia; Parvej Alam; Jacky W. Y. Lam; Ben Zhong Tang
• Keywords: Excimer; Persistent luminescence

Abstract Achieving efficient near‐infrared room‐temperature phosphorescence of purely organic phosphors remains scarce and challenging due to strong nonradiative decay. Additionally, the investigation triplet excimer is rarely reported, despite fact that excimer, a special emitter commonly formed in crystals with π–π interactions, can efficiently change fluorescent properties compounds. Herein, series dithienopyrrole derivatives low energy levels stable states, exhibiting persistent phosphorescence, developed. Via modification halogen atoms, display tunable emissions monomers from 645 702 nm, maximum lifetime 3.68 ms under ambient conditions. Notably, be switched on at temperatures, enabled by noncovalent interactions rigidifying matrix stabilizing excimer. Unprecedentedly, dynamic transition process captured between monomer temperature variations, revealing unstable excimers tendency dissociate result effective quench phosphorescence. Excited state transitions across varying environments are elucidated, interpreting structural dynamics demonstrating strategies for devising novel phosphors.