Axial enantiomers with donor-regulated TADF feature for multicolor circularly polarized electroluminescence  

作　　者：Chen-Hao Guo Wen-Long Zhao Ke-Ke Tan Wei-Chen Guo Liheng Feng Chuan-Feng Chen Meng Li 

机构地区：[1]School of Chemistry and Chemical Engineering,Shanxi University,Taiyuan,030006,China [2]Beijing National Laboratory for Molecular Sciences,CAS Key Laboratory of Molecular Recognition and Function,Institute of Chemistry,Chinese Academy of Sciences,Beijing,100190,China [3]University of Chinese Academy of Sciences,Beijing,100049,China

出　　处：《Science China Chemistry》2024年第6期2039-2045,共7页中国科学（化学英文版）

基　　金：supported by the National Natural Science Foundation of China(22122111,92256304);the Ministry of Science and Technology of China(2022YFA1204401)。

摘　　要：This study optimized the TADF feature of axial chiral enantiomers through precise donor engineering,and multicolor CP-TADFwas achieved in the axial chiral framework.Three pairs of axial enantiomers with donor-regulated TADF feature,namely(R/S)-TPCBD,(R/S)-DPCBD,and(R/S)-DPACBD,were synthesized by introducing carbazole donors with different substituents onto biphenyl cyanide acceptors.As the electron-donating ability of donors increases,the emission of these axial enantiomers ranges from 455,476 to 552 nm,their singlet-triplet energy gaps(ΔE_(ST))gradually decrease from 0.30,0.22 to 0.02 e V,accompanied by an increasement in the transition rate(k_(RISC))of RISC process,and the k_(RISC)of DPACBD could reach up to 7.16×10^(5)s^(-1).These axial enantiomers also exhibit mirror-image CD and circularly polarized luminescence(CPL)properties.Moreover,OLEDs based on TPCBD,DPCBD,and DPACBD as emitter were then fabricated,which displayed blue,green,and orange electroluminescence with EQE_(max)of 13.0%,16.4%,and 25.0%,respectively.The results also exhibited a phenomenon of device efficiency increasing with the enhancement of donor abilities.Notably,the CP-OLEDs using(R/S)-TPCBD,(R/S)-DPCBD and(R/S)-DPACBD as emitters displayed intense CPEL signals with g_(EL)values of 3.4×10^(-3)/-4.1×10^(-3),3.2×10^(-3)/-3.1×10^(-3)and2.3×10^(-3)/-2.1×10^(-3),respectively.By convenient molecular engineering of donor regulation in the same molecular skeleton,CP-TADF materials with multicolor CPEL and improved device performance could be conveniently achieved.

关 键 词：axial chirality thermally activated delayed fluorescence circularly polarized luminescence ELECTROLUMINESCENCE organic light-emitting diodes 

分 类 号：TN383.1[电子电信—物理电子学] O626[理学—有机化学]