Share Email Print
cover

Proceedings Paper

Effects on the spectrum of the blue organic light-emitting diodes by the indium tin oxide surface treatment
Author(s): Xing-qiao Ji; Wei-zhi Li; Zhi-you Zhong; Tao Wang; Ya-dong Jiang
Format Member Price Non-Member Price
PDF $17.00 $21.00

Paper Abstract

Deionized water, sulfur acid (98%) (H2SO4), sodium hydroxide (NaOH) solution and oxygen plasma are used to treat ITO substrates, then blue organic light emitting devices (OLEDs) with the structure of ITO/NPB(50 nm)/BAlq3(40 nm)/Alq3(25 nm)/Mg:Ag are fabricated in the vacuum. The experiment results show that ITO treatments influence the electroluminescence (EL) spectrum of the blue OLEDs, the OLEDs which are treated by four methods the EL spectrums change from 496 to 455 nm. According to atom force microscope (AFM) and X-ray photoelectron spectroscopy (XPS) analysis, the surface morphology and surface composition are greatly changed, so the surface work function is changed, then recombination zone of the carrier is moved, which leading to the emission spectrums alter. The ITO substrate is treated by oxygen plasma, which has the highest oxygen concentration, so the surface work function is the greatest, the hole can jump the barrier and recombine in BAlq3-Alq3 interface, the spectral peak is at 496 nm. The ITO treated by acid solution, the oxygen concentration is less than that of plasma treatment, so the surface work function is also less than it, thus the hole can inject into the BAlq3 layer, the spectral peak is at 480 nm. Roughness of deionized water treated ITO is the largest, which can became local high electric field, so some hole are excitated into the BAlq3-Alq3 interface, most of the hole are blocked by BAlq3 barrier, the light from BAlq3-Alq3 interface and NPB layer, the spectral peak is at 474 nm. The ITO treated by NaOH solution, the oxygen concentration is the lowest, so the surface work function is also the lowest, all of the hole are blocked by BAlq3 layer, they can only recombine in the NPB layer, the spectral peak is at 455 nm.

Paper Details

Date Published: 26 January 2006
PDF: 7 pages
Proc. SPIE 6030, ICO20: Display Devices and Systems, 60300C (26 January 2006); doi: 10.1117/12.667368
Show Author Affiliations
Xing-qiao Ji, Univ. of Electronic Science and Technology of China (China)
Wei-zhi Li, Univ. of Electronic Science and Technology of China (China)
Zhi-you Zhong, Univ. of Electronic Science and Technology of China (China)
Tao Wang, Univ. of Electronic Science and Technology of China (China)
Ya-dong Jiang, Univ. of Electronic Science and Technology of China (China)


Published in SPIE Proceedings Vol. 6030:
ICO20: Display Devices and Systems
Tatsuo Uchida; Xu Liu; Hang Song, Editor(s)

© SPIE. Terms of Use
Back to Top