Tetraphenylethylene-substituted phenothiazine-based AIEgens for non-doped deep-blue organic light-emitting diodes with negligible efficiency roll-off.

Abstract Deep-blue organic light-emitting diodes (OLEDs) with low efficiency roll-off and high color purity are critical for the tetraphenylethylene-based AIEgens derivative. In this work, the novel blue emitter, 3-(1-phenyl-1 H -phenanthro[9,10-d]imidazol-2-yl)-10-(4-(1,2,2-triphenylvinyl)phenyl)-10H-phenothiazine (TPEPPI), was designed and synthesized to develop a new material possessing aggregation-induced emission (AIE) characteristics and deep-blue emission. The TPEPPI hardly emits fluorescence in tetrahydrofuran (THF), the luminescence intensity increased by 5.5 times when the water content reaches 95%, showing strong fluorescence in aggregated state. Three different non-doped device structures were fabricated, all of the OLEDs showed deep-blue emission (∼460 nm). The optimized device Ⅲ exhibited an emission peak at 467 nm, a maximum current efficiency of 4.25 cd A−1, a maximum power efficiency of 3.35 lm W−1, a maximum luminance of 16750 cd m−2, a maximum external quantum efficiency of 2.36%, and the essentially negligible efficiency roll-off of 3.3%, which is the first observation of deep-blue emission using a tetraphenylethylene-substituted phenothiazine-based AIEgens derivative in OLEDs. Graphical abstract Image 1 Highlights • A new AIE-active phenothiazine-based substituted TPE blue emitter was designed. • Non-doped device with essentially negligible efficiency roll-off of 3.3%. • Deep-blue emission with TPE-substituted phenothiazine-based AIEgens derivative. [ABSTRACT FROM AUTHOR]