Abstract

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 ~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 ~3 µs, followed by a structural relaxation to the original CN-Cz2:PO-T2T configuration within ~14 µs.

Details

Title
Probe exciplex structure of highly efficient thermally activated delayed fluorescence organic light emitting diodes
Author
Lin, Tzu-Chieh 1 ; Sarma, Monima 1 ; Yi-Ting, Chen 1 ; Shih-Hung, Liu 1 ; Ke-Ting, Lin 2 ; Pin-Yi Chiang 2 ; Wei-Tsung Chuang 3 ; Yi-Chen, Liu 4 ; Hsu, Hsiu-Fu 4 ; Wen-Yi, Hung 2 ; Tang, Wei-Chieh 1 ; Wong, Ken-Tsung 5 ; Pi-Tai Chou 1 

 Department of Chemistry, National Taiwan University, Taipei, Taiwan 
 Institute of Optoelectronic Sciences, National Taiwan Ocean University, Keelung, Taiwan 
 National Synchrotron Radiation Research Center, Hsinchu City, Taiwan 
 Department of Chemistry, Tamkang University, New Taipei City, Taiwan 
 Department of Chemistry, National Taiwan University, Taipei, Taiwan; Institute of Atomic and Molecular Science, Academia Sinica, Taipei, Taiwan 
Pages
1-8
Publication year
2018
Publication date
Aug 2018
Publisher
Nature Publishing Group
e-ISSN
20411723
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2084328037
Copyright
© 2018. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.