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Thermally Activated Delayed Fluorescent Properties of Ortho ‐Carbazole‐Appended Triazine Compounds
Author(s) -
Mubarok Hanif,
Oh Jihun,
Lee Heechai,
Jung Jaehoon,
Lee Min Hyung
Publication year - 2019
Publication title -
bulletin of the korean chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.237
H-Index - 59
ISSN - 1229-5949
DOI - 10.1002/bkcs.11879
Subject(s) - carbazole , homo/lumo , photochemistry , acceptor , excited state , quantum yield , triazine , chemistry , fluorescence , molecular orbital , photoluminescence , singlet state , materials science , molecule , polymer chemistry , organic chemistry , physics , optoelectronics , quantum mechanics , nuclear physics , condensed matter physics
We report the synthesis and thermally activated delayed fluorescent (TADF) properties of ortho ‐carbazole‐appended triazine compounds. Two donor (D)‐acceptor (A) compounds, CzMe o TRZ ( 1 ) and BuCzMe o TRZ ( 2 ), in which the carbazole (Cz and t ‐BuCz) donor and 4,6‐dipheny‐1,3,5‐triazine (TRZ) acceptor moieties are linked in the ortho position of the 3‐methylphenylene ring were prepared and characterized. Both compounds exhibit broad blue emission at 465 and 487 nm, respectively (photoluminescence quantum yield, Φ PL = 27% and 49% in toluene), which is typical of the donor to acceptor ICT transition. The transient PL decay measurements confirm that both compounds have TADF character with the microsecond‐range delayed lifetimes ( τ d = 1.09 μs for 1 and 1.51 μs for 2 ). Electrochemical analysis indicates that both compounds undergo carbazole‐centered oxidation and triazine‐centered reduction. Theoretical studies further show the twisted D‐A structure, effective separation of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO), and small energy splitting between the excited singlet and triplet states for 1 and 2 , all of which support the observed TADF.