A Novel Spiro[acridine-9,9-fluorene] Derivatives Containing Phenanthroimidazole Moiety for Deep-Blue OLED Application

Typical - stacking and aggregation-caused quenching could be suppressed in the film-state by the spiro conformation molecular design in the field of organic light-emitting diodes (OLEDs). Herein, a novel deep-blue fluorescent material with spiro conformation, 1-(4-(tert-butyl)phenyl)-2-(4-(10-phenyl-10H-spiro[acridine-9,9-fluoren]-2-yl)phenyl)-1H-phenanthro[9,10-d]imidazole (SAF-BPI), was designed and synthesized. The compound consists of spiro-acridine-fluorene (SAF) as donor part and phenanthroimidazole (BPI) as acceptor part. Owing to the rigid SAF skeleton, this compound exhibits a high thermal stability with a glass transition temperature (T-g) of 198 degrees C. The compound exhibits bipolar transporting characteristics demonstrated by the single-carrier devices. The non-doped OLEDs based on the SAF-BPI as the emitting layer shows maximum emission at 448nm, maximum luminance of 2122cdm(-2), maximum current efficiency (CE) of 3.97cdA(-1), and a maximum power efficiency of 2.08lmW(-1). The chromaticity coordinate is stable at (0.15, 0.10) at the voltage of 7-11V. The device shows a slow efficiency roll-off with CE of 3.35 and 2.85cdA(-1) at 100 and 1000cdm(-2), respectively.