Highly efficient white fluorescence/phosphorescence hybrid organic light emitting devices based on an efficient hole-transporting blue emitter

Abstract

4,4'-di-(1-pyrenyl)-4''-[2-(9,9'-dimethylfluorene)]triphenylamine was proved to be a hole-transporting blue emitter with a hole-mobility of 6.40 × 10−5 cm2 V−1 s−1. A blue organic light emitting device using the compound as a fluorescent dopant shows a maximum luminance efficiency of 5.8 cd A−1 (5.2 lm W−1, 4.5%) with Commission Internationale de L'Eclairage coordinates of x = 0.16, y = 0.18. Fluorescence/phosphorescence hybrid white device employed the compound and Ir(2-phq)3 respectively as blue and orange emitter has been fabricated, which shows a warm white emission with a maximum efficiency of 16.8 cd A−1 (16.1 lm W−1). Moreover, high efficiency three-color fluorescence/phosphorescence hybrid white organic light emitting device using the compound as blue fluorescent emitter combining with phosphorescent yellowish-green emitter (Ir(ppy)2bop) and red emitter (Ir(piq)3) has been achieved. The white device shows a maximum efficiency of 42.5 cd A−1 (38.2 lm W−1, 15.5%), with a Color-Rendering Index of 76, which is among the best results for previously reported fluorescence/phosphorescence white devices.