Highly Efficient Red Phosphorescent OLEDs with Simple Device Structure

We report high efficiency red phosphorescent OLEDs with a simple organic bi-layered structure. A host material bis(10-hydroxybenzo[h] quinolinato)beryllium complex (Bebq(2)) having a good electron transporting and energy transfer characteristics and a good hole injection and transport material N,N'-di(4(N, N'-diphenyl-amino)phenyl)-N,N'-diphenylbenzidine (DNTPD) lead to the fabrication of simplified high efficiency device. The driving voltage value of 3.5V to reach luminance of 1000 cd/m(2) is reported. The maximum current-and power-efficiency values of 9.38 cd/A and 11.72 lm/W with real true red color of (0.67, 0.32) are demonstrated.