Impedance spectroscopy of a poly(p-phenylenevinylene)-based light-emitting diode device

Abstract

A poly-p-phenylenevinylene (PPV)-based light-emitting diode (LED) device was studied by means of comprehensive ac impedance measurements. Separate regions of frequency-dependent responses, the bulk and depleted (interface) regions, with distinct electrical proper-ties, were identified and characterized. The ac J-E characteristics revealed the space-charge limited conduction mechanism, which was specifically assigned to the depleted region. Besides, a direct estimate of the trap density in the bulk region was obtained from the applied voltage dependence of the charge concentration. (C) 2003 Elsevier Ltd. All rights reserved.