Share Email Print
cover

Proceedings Paper

Electrical properties of organic light-emitting diodes (OLEDs) studied by impedance spectroscopy in ultra-high vacuum
Author(s): Rudi Ono; Michael Kiy; Ivan Biaggio; Peter Guenter
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Alq3-based organic light emitting diodes (OLEDs) were prepared by molecular beam deposition in Ultra-High Vacuum (UHV) and their electrical properties were studied by impedance spectroscopy before they were exposed to any impurity gases. To characterize the fundamental injection processes, we studied the simplest OLED structure, consisting of a single layer of Alq3 between an ITO anode and a Mg cathode. In UHV, and below the threshold voltage for luminescent, instabilities in the frequency dependence of the resistivity, as well as in the current vs. voltage characteristics, are observed, which could be related to inhomogeneous contacting at the electrodes. When the same experiment is performed in air, both kinds of instabilities disappear, which demonstrates that exposure to atmospheric gas plays a role in stabilizing the contact and injection properties in the devices. Additionally, the impedance spectrum in air below the threshold voltage for luminescent shows an additional feature that hints to two different regions in the Alq3 layer, which we assign to the effect of Mg atoms which diffused into the Alq3 layer during deposition.

Paper Details

Date Published: 2 February 2001
PDF: 8 pages
Proc. SPIE 4105, Organic Light-Emitting Materials and Devices IV, (2 February 2001); doi: 10.1117/12.416908
Show Author Affiliations
Rudi Ono, Swiss Federal Insitute of Technology Zuerich (Switzerland)
Michael Kiy, Swiss Federal Insitute of Technology Zuerich (Switzerland)
Ivan Biaggio, Swiss Federal Insitute of Technology Zuerich (Switzerland)
Peter Guenter, Swiss Federal Insitute of Technology Zuerich (Switzerland)


Published in SPIE Proceedings Vol. 4105:
Organic Light-Emitting Materials and Devices IV
Zakya H. Kafafi, Editor(s)

© SPIE. Terms of Use
Back to Top