Probe exciplex structure of highly efficient thermally activated delayed fluorescence organic light emitting diodes

被引：123

作者：

Lin, Tzu-Chieh ^{[1
]}

Sarma, Monima ^{[1
]}

Chen, Yi-Ting ^{[1
]}

Liu, Shih-Hung ^{[1
]}

Lin, Ke-Ting ^{[2
]}

Chiang, Pin-Yi ^{[2
]}

Chuang, Wei-Tsung ^{[3
]}

Liu, Yi-Chen ^{[4
]}

Hsu, Hsiu-Fu ^{[4
]}

Hung, Wen-Yi ^{[2
]}

Tang, Wei-Chieh ^{[1
]}

Wong, Ken-Tsung ^{[1
,5
]}

Chou, Pi-Tai ^{[1
]}

机构：

[1] Natl Taiwan Univ, Dept Chem, Taipei 10617, Taiwan

[2] Natl Taiwan Ocean Univ, Inst Optoelect Sci, Keelung 202, Taiwan

[3] Natl Synchrotron Radiat Res Ctr, Hsinchu 30076, Taiwan

[4] Tamkang Univ, Dept Chem, New Taipei 25137, Taiwan

[5] Acad Sinica, Inst Atom & Mol Sci, Taipei 10617, Taiwan

来源：

NATURE COMMUNICATIONS | 2018年 / 9卷

关键词：

EXTERNAL QUANTUM EFFICIENCY; OPERATIONAL STABILITY; MOLECULAR DESIGN; EMITTERS; STRATEGY; ENERGY;

D O I：

10.1038/s41467-018-05527-4

中图分类号：

O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];

学科分类号：

07 ; 0710 ; 09 ;

摘要：

The lack of structural information impeded the access of efficient luminescence for the exciplex type thermally activated delayed fluorescence (TADF). We report here the pump-probe Step-Scan Fourier transform infrared spectra of exciplex composed of a carbazole-based electron donor (CN-Cz2) and 1,3,5-triazine-based electron acceptor (PO-T2T) codeposited as the solid film that gives intermolecular charge transfer (CT), TADF, and record-high exciplex type cyan organic light emitting diodes (external quantum efficiency: 16%). The transient infrared spectral assignment to the CT state is unambiguous due to its distinction from the local excited state of either the donor or the acceptor chromophore. Importantly, a broad absorption band centered at similar to 2060 cm(-1) was observed and assigned to a polaron-pair absorption. Time-resolved kinetics lead us to conclude that CT excited states relax to a ground-state intermediate with a time constant of similar to 3 mu s, followed by a structural relaxation to the original CN-Cz2:PO-T2T configuration within similar to 14 mu s.

引用

页数：8

共 28 条

[1] "Rate-limited effect" of reverse intersystem crossing process: the key for tuning thermally activated delayed fluorescence lifetime and efficiency roll-off of organic light emitting diodes [J].