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)2Ir(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 (CIE(x, y)) coordinates of (0.33, 0.42) at 22400 cd/m2, a maximum luminance of 27300 cd/m2 at 13.2 V, and a maximum luminous efficiency of 26.9 cd/A.