Effect of Plasma Treatment of ITO Electrode on the Characteristics of Green OLEDs with Alq3-C545T Emissive Layer

• Published in: Molecular Crystals and Liquid Crystals 2009-01, Vol.498 (1), p.274-283
• Main Authors: Jang, Ji Geun, Shin, Se Jin, Lim, Sung Kyoo, Chang, Ho Jung, Ryu, Sang Ouk, Gong, Myoung Seon, Lee, Jun Yeob
• Format: Article
• Language: English
• Subjects: Alq; C545T; CIE coordinate; Fluorescence; luminance; OLED; Organic light emitting diodes; Plasma; plasma treatment; power efficiency; Process engineering; Ratios
• ISSN: 1542-1406; 1563-5287; 1527-1943; 1543-5318
• DOI: 10.1080/15421400802619602

The influence of the plasma treatment of the ITO (Indium Tin Oxide)/glass substrate was investigated in the fabrication of green OLEDs (Organic Light Emitting Devices) using the Alq 3 -C545T fluorescent system. Various plasma powers of 100 W, 150 W, and 200 W were used under the fixed conditions of an Ar/O 2 gas mixing ratio of 0.5 and pressure of 1 m Torr during the plasma treatment. The threshold times required for the inter-insulator width between the subpixel regions to be reduced to 80% of their original value were found to be 4, 3, and 2 minutes at plasma powers of 100 W, 150 W, and 200 W, respectively. The plasma treatment durations at each power were varied from 1 minute up to the threshold time with intervals of one minute. The basic structure of the fabricated devices was 2TNATA/NPB/Alq 3 -C545T/Alq 3 /LiF/Al and the best emission characteristics were obtained in the case of the plasma treatment at 150 W for 2 minutes. The luminance and power efficiency of the device treated with the optimum plasma condition were 20000 cd/m 2 and 16 lm/W at 10 V, respectively. The peak wavelength and the CIE coordinates were found to be 522 nm and (0.32, 0.63), respectively.