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Investigation of excited‐state dynamics upon both photo‐excitation and electro‐excitation of thermally activated delayed fluorescent molecules
Author(s) -
Wang Peng,
Huang Qingyu,
Zhao Suling,
Xu Zheng,
Song Dandan,
Qiao Bo,
Zheng Weiye,
Chen Junfei,
Yan Guang
Publication year - 2018
Publication title -
journal of the society for information display
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 52
eISSN - 1938-3657
pISSN - 1071-0922
DOI - 10.1002/jsid.737
Subject(s) - oled , electroluminescence , exciton , materials science , dopant , fluorescence , excitation , optoelectronics , singlet state , excited state , excimer , triplet state , absorption (acoustics) , molecule , photochemistry , doping , chemistry , atomic physics , optics , nanotechnology , physics , condensed matter physics , organic chemistry , quantum mechanics , layer (electronics) , composite material
Exciton dynamics is one of the core issues lies in the field of achieving high efficiency organic light‐emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) molecules. The authors briefly review the host dependence of TADF dopant and then discuss the host–guest interaction in TADF OLEDs. By the means of transient electroluminescence measurement, the dynamics of triplet and singlet excitons are studied. Results show that host material with high T1 energy levels, large spectral overlap with TADF dopant's absorption, and free of exciplex formation exhibits higher TADF character. Furthermore, the underlying reason for the efficiency roll‐off of the TADF OLEDs is clarified to be attributed to deeply trapped charges.