High-Efficiency White Organic Light-Emitting Diodes Using Blue and Red Phosphorescent Materials with Exciton Blocking Layer

Abstract

High-efficiency white organic light-emitting diodes (WOLEDs) were fabricated with two emissive layers and an exciton blocking layer (EBL) was sandwiched between two phosphorescent dyes, bis(3,5-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl) iridium III (Flrpic) as the blue emission and iridium(III) bis(5-acetyl-2-phenylpyridinato-N,C2') acetylacetonate ((acppy)(2)Ir(acac)) as the red emission. This EBL effectively prevented a triple-triple energy transfer between the two phosphorescent emissive layers with blue and red emission. The white device showed Commission Internationale De L'Eclairage (CIEx,y) coordinates of (0.33, 0.42) at 22400 cd/m(2), a maximum luminance of 27300 cd/m(2) at 13.2 V, and a maximum luminous efficiency of 26.9 cd/A.