Open AccessAxially Chiral Biphenyl Compound‐Based Thermally Activated Delayed Fluorescent Materials for High‐Performance Circularly Polarized Organic Light‐Emitting Diodes
Author(s) -
Tu ZhenLong,
Yan ZhiPing,
Liang Xiao,
Chen Lei,
Wu ZhengGuang,
Wang Yi,
Zheng YouXuan,
Zuo JingLin,
Pan Yi
Publication year - 2020
Publication title -
advanced science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.388
H-Index - 100
ISSN - 2198-3844
DOI - 10.1002/advs.202000804
Subject(s) - biphenyl , axial symmetry , fluorescence , materials science , oled , diode , optoelectronics , circular polarization , photochemistry , optics , chemistry , nanotechnology , organic chemistry , physics , layer (electronics) , microstrip , quantum mechanics
To boost intrinsic circularly polarized luminescence (CPL) properties of chiral emitters, an axially chiral biphenyl unit is inlaid in thermally activated delayed fluorescent (TADF) skeleton, urging the participation of chiral source in frontier molecular orbital distributions. A pair of enantiomers, ( R )‐BPPOACZ and ( S )‐BPPOACZ, containing the cyano as electron‐withdrawing moieties and carbazole and phenoxazine as electron‐donating units are synthesized and separated. The circularly polarized TADF enantiomers exhibit both high photoluminescence quantum yield of 86.10% and excellent CPL activities with maximum dissymmetry factor | g PL | values of almost 10 −2 in solution and 1.8 × 10 −2 in doped film, which are among the best values of previously reported small chiral organic materials. Moreover, the circularly polarized organic light‐emitting diodes based on the TADF enantiomers achieve the maximum external quantum efficiency of 16.6% with extremely low efficiency roll‐off. Obvious circularly polarized electroluminescence signals with | g EL | values of 4 × 10 −3 are also recorded.