Preparation and characterization of phosphorescence organic light emitting diodes using PVK:Ir(ppy)_3 emission layer

摘要

The phosphorescence polymer LEDs (PhPLEDs) with the structure of ITO/PEDOT:PSS/PVK:Ir(ppy)_3/TPBI/LiF/Al were fabricated and investigated on the electrical and optical properties at variations doping concentrations (0.5wt% to 2.5wt%) of Ir(ppy)_3. PVK(poly-vinylcarbazole) and Ir(ppy)_3[tris(2-phenylpyridine)iridium(III)] polymers were used as the host and guest materials for the emission layer. TPBI was introduced to improve the light efficiency of the devices. The maximum luminance and current density for PhPLED were about 8600 cd/m~2 and 155 mA/cm~2 at 7 V, when the TPBI layer was introduced between emission and cathode electrode film. The emission spectrum and the CIE color coordinator were about 512nm and x, y = 0.28, 0.63, respectively, showing green color.