摘要
Yellow emission is crucial in RGBY display technology and in fabricating physiologically friendly, low color-temperature lighting sources. Emitters with both wet- and dry-process feasibility are highly desirable to fabricate, respectively, high-quality devices via vapor deposition and cost-effective, large-area devices via roll-to-roll fabrication. Here, high-efficiency organic light-emitting diodes with a novel wet- and dry-process feasible yellow-emitting iridium complex, bis[5-methyl-7-fluoro-5H-benzo(c)(1,5) naphthyridin-6-one] iridium (picolinate), are demonstrated. By spin coating, the device shows, at 1000 cd m -2 , an external quantum efficiency (EQE) of 18.5% with an efficacy of 52.3 lm W -1 , the highest among all reported yellow devices via wet-process, while using vapor deposition, the EQE is 22.6% with a 75.1 lm W -1 efficacy, the highest among all dry-processed counterparts. The high efficiency may be attributed to the replacement of the hydrogen atom with a fluorine atom on a 2-substitutional site in the emitter to prevent dense molecular packing-caused self-quenching and to reduce radiationless deactivation rates, leading to a high quantum yield (71%). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.