Tetra-coordinated difluoroboron TADF emitter for sky-blue organic light-emitting diodes with 27.4%external quantum efficiency  

作　　者：Feng Zhan Weiwei Lou Hongjian Zheng Guijie Li Yuanbin She 

机构地区：[1]State Key Laboratory of Green Chemistry Synthesis Technology,College of Chemical Engineering,Zhejiang University of Technology,Hangzhou 310014,China

出　　处：《Science China Chemistry》2025年第3期1026-1034,共9页中国科学(化学英文版)

基　　金：supported by the National Natural Science Foundation of China (22178319,22138011)。

摘　　要：Tetra-coordinated fluoroboron compounds have garnered significant attention in organic light-emitting diodes(OLEDs)due to their remarkable optoelectronic properties and high chemical stability.However,the design of novel tetra-coordinated fluoroboron-based blue thermally activated delayed fluorescence(TADF)materials with excellent external quantum efficiency(EQE)remains crucial.In this study,a novel tetra-coordinated difluoroboron-based blue TADF material with 3,6-diphenylcarbazole donor and 2-(4-phenylpyridin-2-yl)phenolate difluoroboron acceptor molecular skeleton has been designed and synthesized.Benefiting from the larger dihedral angle(68.0°)between the donor and acceptor moieties,the compound m-PhCz-BF2 exhibited a smaller singlet-triplet energy splitting(ΔE_(ST))value of 0.043 eV.As a result,a sky-blue emission with peak wavelengths of 491 and 487 nm and photoluminescence quantum yields(PLQY)of 93%and 99%were obtained in solution and doped film,respectively.Additionally,the m-PhCz-BF2 doped OLED demonstrated sky-blue electroluminescence(Commission Internationale de l'éclairage,CIE_(y)≤0.33)and a high peak EQE of 27.4%with maximum brightness of 17,493 cd/m~2.Notably,these devices also achieved a high current efficiency of 62.5 cd/A and a power efficiency of 49.4 lm/W.These remarkable performances indicate that the m-PhCz-BF2 has the potential to function as a highly efficient TADF dopant for the fabrication of sky-blue OLEDs.

关 键 词：thermally activated delayed fluorescence organic light-emitting diodes tetra-coordinated difluoroboron blue emitter 

分 类 号：TN383.1[电子电信—物理电子学] O641.4[理学—物理化学]