A stable red organic light-emitting diode based on a pentacene derivative

This work presents red organic light-emitting diodes based on tris-(8-hydroxy-quinolinato) aluminum (Alq₃) co-doped with a new pentacene derivative, 6,13-di-(3,5-diphenyl)phenylpentacene(PDT), and 5,6,11,12-tetraphenylnaphthacene(rubrene). The experimental results suggest that rubrene is doped as an assist dopant to enhance energy transfer from Alq₃ to PDT in Alq₃:PDT:rubrene, which results in good color purity of red emission. For the device with the emitting layer of [Alq₃:3mol%PDT:1 mol%rubrene(60nm)], a stable red emission (chromaticity coordinate: x=0.61, y=0.37) is obtained within the driving current density range of 12 to 120mA/cm². The luminance is 4400cd/m² at 21V. And a maximum luminance efficiency of 2.4cd/A is measured at current density of 120mA/cm².