Red organic light emitting device made from triphenylene hexaester and perylene tetraester

Saturated red light emission from organic light emitting diodes is less com mon than emission in the green or the blue. Most organic red light emitting devices are based on rare earth complexes, mainly europium, which are know n to exhibit stability problems. The present article describes new diodes m ade of indium tin oxide-coated glass/triphenylene hexaether/perylene tetrae ster/aluminum. The band diagram was determined by ultraviolet photoemission spectroscopy, cyclic voltammetry, scanning tunneling microscopy, and absor bance measurements. The interfaces between electrodes and organic layers we re investigated by x-ray photoelectron spectroscopy. The current-voltage an d luminance-voltage characteristics are very reproducible from device to de vice, with an emission peak at 620 nm and a full width at half maximum of 8 0 nm, a current rectification ratio of about 30, I similar toV(2) at low vo ltages and I similar to Lum similar toV(6) at higher voltages. (C) 2001 Ame rican Institute of Physics.