Studies on organic light-emitting diodes based on rubrene-doped zinc quinolate

✍ Scribed by Saxena, Kanchan ;Mehta, Dalip Singh ;Rai, Virender Kumar ;Srivastava, Ritu ;Chauhan, Gayatri ;Kamalasanan, M. N. ;Jain, V. K.

• Publisher: John Wiley and Sons
• Year: 2009
• Tongue: English
• Weight: 232 KB
• Volume: 206
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/pssa.200824516

✦ Synopsis

Abstract

We report on the fabrication and performance of organic light‐emitting diodes (OLEDs) employing rubrene‐doped metal chelate namely, zinc quinolate (Znq~2~) as emissive layer. Different OLED architectures were carried out to improve the device performance by doping varying concentrations (by wt%) of rubrene dye into Znq~2~ host. Enhanced electroluminescence (EL) intensity was achieved using oxygen‐plasma‐treated indium tin oxide as anode, N,N′‐di‐1‐naphthyl‐N,N′‐diphenyl‐1,1′‐biphenyl‐4,4′diamine (α‐NPD) as hole‐transport layer, 10 weight percent rubrene‐doped Znq~2~ as emission layer, Znq~2~ as electron‐transport layer, LiF as electron‐injection layer and aluminum as cathode. It has been demonstrated that by using Znq~2~ as electron‐transport layer and host for dopant (rubrene) is the most suitable device structure for achieving low drive voltage and high efficiency. Electroluminescence spectra of rubrene‐doped OLED devices were also studied. The EL spectral peak was found to be shifted to 565 nm and spectral full‐width at half maximum (FWHM) of rubrene‐doped device was found to be 58 nm, while it was 95 nm in the case of a pure Znq~2~‐based OLED device. No further significant changes in EL spectra, such as, spectral broadening, narrowing or peak shifting were observed on changing the concentration of the rubrene dye. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)