High-performance fluorescent/phosphorescent (F/P) hybrid white OLEDs consisting of a yellowish-green phosphorescent emitter

Abstract

The color rendering index (CRI) of a white organic-light emitting device (WOLED) employing standard red + green + blue emitters is typically limited by the deep valley between the red and the green emission peaks. To address this issue without increasing device complexity, we synthesized a yellowish-green iridium emitter, iridium(III) bis(2-phenylpyridine)(2-(benzo[d]oxazol-2-yl)phenol) (Ir(ppy)₂bop), for replacing the standard green emitter. By combining emissions from Ir(ppy)₂bop with those from a blue fluorescent emitter and a red phosphor, a high performance fluorescent/phosphorescent (F/P) WOLED has been fabricated. The device gives white emission with a maximum efficiency of 55.2 cd A⁻¹ (49.6 lm W⁻¹) and an EQE value of 20% without any light extraction technologies. It is noteworthy that the color rendering index (CRI) of the white OLED reaches up to 89. Considering both the efficiency and the CRI, these results are among the best-reported white OLEDs.