Substituent position engineering of diphenylquinoline-based Ir(III) complexes for efficient orange and white PhOLEDs with high color stability/low efficiency roll-off using a solution-processed emission layer
- Authors
- Sarada, Ganguri; Yoon, Juho; Cho, Woosum; Cho, Minji; Cho, Daw Won; Kang, Sang Ook; Nam, Yeonsig; Lee, Jin Yong; Jin, Sung-Ho
- Issue Date
- 2016
- Publisher
- ROYAL SOC CHEMISTRY
- Citation
- JOURNAL OF MATERIALS CHEMISTRY C, v.4, no.1, pp.113 - 120
- Indexed
- SCIE
SCOPUS
- Journal Title
- JOURNAL OF MATERIALS CHEMISTRY C
- Volume
- 4
- Number
- 1
- Start Page
- 113
- End Page
- 120
- URI
- https://scholar.korea.ac.kr/handle/2021.sw.korea/90301
- DOI
- 10.1039/c5tc03004h
- ISSN
- 2050-7526
- Abstract
- Three new heteroleptic Ir(III) complexes o-LIrpic, m-LIrpic, and p-LIrpic (L = CF(3)DPQ) consisting of 2,4-diphenylquinoline (DPQ) with a - CF3 group at ortho (o)/meta (m)/para (p) positions of the metalated phenyl ring, respectively, as the main ligands were synthesized and used as emitters in phosphorescent organic light-emitting diodes (PhOLEDs). We realized that - CF3 position extremely affects the crucial photophysical and electronic properties such as emission color, photoluminescence quantum yield (PLQY) and energy levels of these Ir(III) complexes resulting in - CF3 position-dependent performance of their PhOLEDs. To verify the effect of - CF3 group position on device performance, three other Ir(III) complexes o-LIrtmd, m-LIrtmd, and p-LIrtmd were synthesized using the same main ligands but a different ancillary ligand. In the two series of Ir(III) complexes, the devices with m-CF3 based complexes are outstanding in performance compared to o-or p-CF3 based ones due to the enhanced PLQY and well suppressed non-radiative deactivations by m-substitution. Finally, the single emission layer solution-processed orange and two-component white PhOLEDs fabricated using m-LIrpic as orange emitter achieved the maximum external quantum efficiency of 17.1% (43.9 cd A(-1)) and 21.1% (48.8 cd A(-1)), respectively, with highly stable color coordinates and low efficiency roll-off. This is the highest efficiency reported to date for solution-processed orange PhOLEDs using a small molecular host with easily accessible emitter.
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Collections - Graduate School > Department of Advanced Materials Chemistry > 1. Journal Articles
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