ScienceAsia 51S (2023): 1-11 |doi:
10.2306/scienceasia1513-1874.2023.s011
5,6-Dicyano[2,1,3]benzothiadiazole-based deep red/near
infrared thermally activated delayed fluorescence emitter for
efficient electroluminescent devices
Pattarapapa Janthakita, Jakkapan Kumsampaoa, Rattanasiri Wannapakdeea, Atthapon Saenubola,
Wijitra Waengdongbunga, Taweesak Sudyoadsukb, Vinich Promaraka,*,?
ABSTRACT: Deepredtonear-infrared organic light-emitting diodes (DR/NIR-OLEDs) have remarkably attracted much
interest due to their potential applications in many areas. Herein, we present a simple structured near-infrared
thermally activated delayed fluorescence (TADF) molecule (DMACCNBz) comprising a strong electron-accepting core
(A) of 5,6-dicyano[2,1,3]benzothiadiazole (CNBz) end-capped with highest-energy molecular orbital (HOMO), rigid
structure, and two strong electron donors (D) of 9,9-dimethyl-9,10-dihydroacridine (DMAC), thereby formulating a D
A-D type chromophore. The experimental and theoretical studies confirm that DMACCNBz is a TADF fluorophore
with NIR emission (?PL = 738 nm) and a small singlet-triplet splitting energy (?EST) of 0.07 eV. DMACCNBz is
successfully applied as an emissive material in DR/NIR-OLEDs. The device using DMACCNBz 10 wt% doped emissive
layer demonstrates a record-setting external quantum efficiency (EQE) of 7.19% with an emission peak at 696 nm,
while the device using 30 wt% doping of DMACCNBz exhibits NIR emission with a peak at 722 nm, an EQE of 4.93%,
and a maximum radiance of 4720 mW sr?1m?2.
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| a |
Department of Materials Science and Engineering, School of Molecular Science and Engineering, Vidyasirimedhi
Institute of Science and Technology, Rayong 21210 Thailand |
| b |
Frontier Research Center, Vidyasirimedhi Institute of Science and Technology, Rayong 21210 Thailand |
* Corresponding author, E-mail: vinich.p@vistec.ac.th
Received 16 Oct 2024, Accepted 20 Apr 2025
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