Low resistance and high work-function WO3/Ag/MoO2 multilayer as transparent anode for bright organic light-emitting diodes. (8th January 2015)

• Record Type: Journal Article
• Authors: Liu, Shun-Wei; Lee, Chih-Chien; Cheng, An-Kuei; Lin, Chun-Feng; Li, Ya-Ze; Su, Tsung-Hao
• Is Part Of: Japanese journal of applied physics. Volume 54:Number 3(2015:Mar.)Supplement
• Publication Date: 2015-01-08
• Subjects: Physics -- Periodicals; 621.05
• DOI: 10.7567/JJAP.54.03CC01
• Languages: English
• ISSNs: 0021-4922

Abstract

Abstract: The authors report efficient organic light-emitting diodes (OLEDs) using a highly conductive transparent WAM multilayer as anode electrode [WAM = WO3 (30 nm)/Ag (10 nm)/MoO2 (5 nm)], which was prepared by thermal evaporation in room temperature conditions to form a smooth morphology on the anode surface, leading to reduction of the injection barrier between the metal/organic interface. The WAM anode shows a low sheet resistance of 8.27 Ω/sq, suitable injection work function of ∼5.65 eV, and high optical transmittance of ∼80% at a range of visible light from 400 to 550 nm. In addition, a hole-only WAM-device by atomic force microscopy and electrical characterizations demonstrates that an efficient hole injection property exists at the WAM/ N, N ′-bis(naphthalene-l-yl)- N, N ′-bis(phenyl)-benzidine interface as compared with the standard transparent conductive oxide of indium tin oxide. From the device characterization, the device performance of a green fluorescent OLED based on WAM anode exhibiting a high brightness of 120000 cd/m 2 and current efficiency of 20 cd/A at a driving voltage of 8 V has been achieved. The operational lifetime of WAM-device was measured to be 10 h ( T 88 lifetime) at an initial luminance of 3450 cd/m 2 because of WAM anode with stable electrical properties in air environment.