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Indexed by:期刊论文

Date of Publication:2017-11-15

Journal:APPLIED SURFACE SCIENCE

Included Journals:Scopus、SCIE、EI

Volume:422

Page Number:125-129

ISSN No.:0169-4332

Key Words:Surface modification; Electrochemical treatment; Organic light-emitting diodes; Tin-doped indium oxide

Abstract:We demonstrate an environment-friendly, simple, and low energy cost approach as an alternative to conventional O-2 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 similar to 3 mW in our approach, which is five orders of magnitude lower than that of O-2 plasma treatment (similar to 100 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,N'i-di-1-naphthyl-N, Ni-diphenylbenzidine, CBP is 4'-bis(carbazol-9-yl) biphenyl, TPBi is 2,2',2 ''-(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 W-1 and external quantum efficiency (EQE) of 24.2% were achieved, respectively, which was slightly higher than that of the OLED fabricated on O-2-plasma-treated ITO (91.2 lm W-1, EQE = 23.1%). (C) 2017 Elsevier B.V. All rights reserved.