Facilitating intrinsic delayed fluorescence of conjugated emitters by inter-chromophore interaction.

Autor: Gao Y; Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China xiaonanma@tju.edu.cn., Sun Y; State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University Tianjin 300071 P. R. China dongbing.chem@nankai.edu.cn., Guo Z; Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China xiaonanma@tju.edu.cn., Yu G; Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China xiaonanma@tju.edu.cn., Wang Y; Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China xiaonanma@tju.edu.cn., Wan Y; College of Chemistry, Beijing Normal University Beijing 100875 P. R. China., Han Y; Engineering Research Center for Nanomaterials, Henan University Kaifeng 475004 P. R. China., Yang W; Engineering Research Center for Nanomaterials, Henan University Kaifeng 475004 P. R. China., Zhao D; State Key Laboratory and Institute of Elemento-Organic Chemistry, College of Chemistry, Nankai University Tianjin 300071 P. R. China dongbing.chem@nankai.edu.cn., Ma X; Institute of Molecular Plus, Tianjin University Tianjin 300072 P. R. China xiaonanma@tju.edu.cn.
Jazyk: angličtina
Zdroj: Chemical science [Chem Sci] 2024 Sep 20. Date of Electronic Publication: 2024 Sep 20.
DOI: 10.1039/d4sc05494f
Abstrakt: Delayed fluorescence (DF) is a unique emitting phenomenon of great interest for important applications in organic optoelectronics. In general, DF requires well-separated frontier orbitals, inherently corresponding to charge transfer (CT)-type emitters. However, facilitating intrinsic DF for local excited (LE)-type conjugated emitters remains very challenging. Aiming to overcome this obstacle, we demonstrate a new molecular design strategy with a DF-inactive B,N-multiple resonance (MR) emitter as a model system. Without the necessity of doping with heavy atoms, we synthesized a co-facial dimer in which an excimer-like state (S exc ) was expected to facilitate efficient reverse intersystem crossing (RISC, T 1 → S exc ) and intrinsic DF. Benefiting from greatly enhanced SOC and reduced Δ E ST , the proof-of-concept emitter Np-2CzB exhibited k RISC up to 6.5 × 10 5 s -1 and intrinsic DF with >35% contribution ( Φ DF / Φ F ) in dilute solution. Further investigation indicated that S exc state formation relies on an optimized co-facial distance ( d = ∼4.7 Å), strong inter-chromophore interaction ( J coul > 450 cm -1 ) and a rigid structure ( Γ S 1 →S 0 < 350 cm -1 ). Although our strategy was demonstrated with a B,N-MR emitter, it can be applicable to many LE-type conjugated emitters without intrinsic DF. By triggering potential DF emission, many classic emitters might play a more important role in optoelectronics.
Competing Interests: The authors declare no competing financial interest.
(This journal is © The Royal Society of Chemistry.)
Databáze: MEDLINE
Externí odkaz: