Photometric and electrical characterizations of large area OLEDs aged under thermal and electrical stresses

The aim of this paper is to identify the electrical signatures of degradations of large area organic light emitting diodes, subjected to various stress conditions. Three Philips GL55 OLEDs were stressed under three distinct temperature values; 23°C, 40°C and 60°C at a stress current density of J=15 mA/cm
²
(rated current density: Jn=9.49 mA/cm
²
). Under thermal and electrical stresses, an increase of the operating voltage was observed with stress time but thermal stress alone did neither affect the operating voltage nor the luminance values up to 60°C.