Ln 3+ Induced Thermally Activated Delayed Fluorescence of Chiral Heterometallic Clusters Ln 2 Ag 28

• Published in: Angewandte Chemie International Edition Vol. 63; no. 40; p. e202410414
• Main Authors: Wang, Xue-Tao, He, Sheng-Rong, Lv, Fang-Wen, Wang, Xue-Ting, Hong, Mei-Xin, Cao, Lingyun, Zhuang, Gui-Lin, Chen, Cheng, Zheng, Jun, Long, La-Sheng, Zheng, Xiu-Ying
• Format: Journal Article
• Language: English
• Published: Germany 01.10.2024
• Subjects: Cluster; Lanthanide; Thermally Activated Delayed Fluorescence; Chiral
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202410414

A series of TADF-active compounds: 0D chiral Ln-Ag(I) clusters L-/D-Ln Ag -0D (Ln=Eu/Gd) and 2D chiral Ln-Ag(I) cluster-based frameworks L-/D-Ln Ag -2D (Ln=Gd) has been synthesized. Atomic-level structural analysis showed that the chiral Ag(I) cluster units {Ag S } in L-/D-Ln Ag -0D and L-/D-Ln Ag -2D exhibited similar configurations, linked by varying numbers of [Ln(H O) ] (x=6 for 0D, x=3 for 2D) to form the final target compounds. Temperature-dependent emission spectra and decay lifetimes measurement demonstrated the presence of TADF in L-Ln Ag -0D (Ln=Eu/Gd) and L-Gd Ag -2D. Experimentally, the remarkable TADF properties primarily originated from {Ag S } moieties in these compounds. Notably, {Ag S } in L-Eu Ag -0D and L-Gd Ag -2D displayed higher promote fluorescence rate and shorter TADF decay times than L-Gd Ag -0D. Combined with theoretical calculations, it was determined that the TADF behaviors of {Ag S } cluster units were induced by 4 f perturbation of Ln ions. Specially, while maintaining ΔE(S -T ) small enough, it can significantly increase k(S →S ) and reduce TADF decay time by adjusting the type or number of Ln ions, thus achieving the purpose of improving TADF for cluster-based luminescent materials.