Enhancement of the lifetime in organic light-emitting devices fabricated utilizing wide-bandgap-impurity-doped emitting layers

• Published in: Thin solid films Vol. 516; no. 11; pp. 3610 - 3613
• Main Authors: Choo, D.C., Bang, H.S., Kwack, B.C., Kim, T.W., Seo, J.H., Kim, Y.K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 01.04.2008; Elsevier Science
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electronics; Exact sciences and technology; Luminescence mechanism; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Optoelectronic devices; Organic light-emitting device; Other luminescence and radiative recombination; Physics; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Stepwise doped hole transport layer; Luminescence mechanism; Stepwise doped hole transport layer; Organic light-emitting device; 78. 66. Qn; 78. 60. Fi; Aluminium compounds; Doping; Luminescence; Quinoline derivatives; Light emitting diodes; Charge density; Lifetime; Optical properties; Organic light emitting diodes; Wide band gap semiconductors; Carrier density
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/j.tsf.2007.08.049

The degradation behaviors of the electrical and the optical properties of organic light-emitting devices (OLEDs) fabricated with an emitting layer (EML) doped with or without a wide-bandgap-impurity were investigated. The OLEDs with a wide-bandgap-doped Alq 3 EML were more stable than those with an undoped Alq 3 EML. The existence of the doped wide-bandgap-impurity in the EML decreased the trap-charge density in the EML, resulting in an increase in the number of electrons in the Alq 3 EML. That increases in the number of electron in the Alq 3 EML for the OLEDs with a wide-bandgap-impurity decreased the staying time of the holes in the Alq 3 EML, resulting in an enhanced lifetime for the OLEDs. These results indicate that OLEDs with a wide-bandgap-impurity-doped EML hold promise for potential applications in long-lifetime OLED displays.