Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5347525 | Applied Surface Science | 2017 | 21 Pages |
Abstract
We demonstrate an environment-friendly, simple, and low energy cost approach as an alternative to conventional O2 plasma treatment to modify the surface of indium tin oxide (ITO) anodes for use in organic light-emitting diodes (OLEDs). ITO is electrochemically treated in NaCl aqueous solution. A chlorinated ITO (Cl-ITO) electrode with a work function of 5.41 eV was obtained, which is 0.66 eV higher than that of pre-cleaned ITO. The increase of work function is due to the anodic oxidation reactions occurred on the surface of ITO. The power dissipation is only â¼3 mW in our approach, which is five orders of magnitude lower than that of O2 plasma treatment (â¼100 W). We fabricated the OLEDs with the configuration of Cl-ITO/NPB(35 nm)/CBP:Ir(ppy)3 (15 nm, 8 wt%)/TPBi:Ir(ppy)3 (10 nm, 8 wt%)/TPBi (10 nm)/Bphen (50 nm)/Cs2CO3 (2 nm)/Al (100 nm), where NPB is N, Å-di-1-naphthyl-N, Å-diphenylbenzidine, CBP is 4â²-bis(carbazol-9-yl)biphenyl, TPBi is 2,2â²,2â³-(1,3,5-benzinetriyl)-tris(1-phenyl-1-H-benzimidazole), Ir(ppy)3 is bis(3-phenylpyridine) iridium(III) and Bphen is 4,7-diphenyl-1,10-phenanthroline. A maximum power efficiency of 95.0 lm Wâ1 and external quantum efficiency (EQE) of 24.2% were achieved, respectively, which was slightly higher than that of the OLED fabricated on O2-plasma-treated ITO (91.2 lm Wâ1, EQE = 23.1%).
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Chao Sun, Chuan Hui Cheng, Bi Long Zhang, Ruo Xuan Li, Yuan Wang, Wei Feng Liu, Ying Min Luo, Guo Tong Du, Shu Lin Cong,