Deep blue fluorescent emitters based imidazole and carbazole for non-doped organic light emitting diodes with CIEy≤0.05

Abstract

Two fluorescent emitters based imidazole and carbazole were synthesized for deep blue emission organic light-emitting diodes (OLED) with non-doped structure. The photophysical, thermal and electrochemical properties are investigated with high decomposition temperature up to 391 and 380 °C, and strong deep blue emission. Single carrier devices were also fabricated to show that two compounds have good bipolar carrier transport characteristic. The non-doped fluorescent OLED devices using the two compounds as emitting layers are designed among which the devices achieved the maximum external quantum efficiency of 1.66% and 1.56%, respectively. Besides, the deep blue emission peak of 412 nm with Commission Internationale de l’Eclairage (CIE) coordinate of (0.16, 0.04), and 420 nm with CIE coordinate of (0.16, 0.05) were also realized. The small CIEy value of 0.04 and 0.05 obtained in this work are very significant for high color purity full-color display, which is also among the best CIEy value results ever reported as deep blue bipolar emitters.