Modulated Infrared Electroluminescence From Organic Light-Emitting Diodes

Modulated infrared electroluminescence from organic light-emitting diodes (OLEDs) based on rare earth complexes (tris-dibenzoylmethanato-mono-bathophenanthroline) erbium or neodymium were fabricated. The modulations were realized by varying the device configuration and by varying an applied forward bias at room temperature. We found that the intensity of EL peak at 1.54 mum was reduced by a factor of almost 20 times as the Nd complex layer thickness in the OLEDs was increased from 1 nm to 5 nm. The intensity ratio of the 1.54 mum (Nd) to 1.06 mum (Er) decreases from 0.82 to 0.53 as the forward bias increases from 6.5 V to 18 V. The effects of the modulation of these IR emissions were also discussed.