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High performance with color stability and simplified device structure with uncomplicated fabrication processes are research focuses in white organic light-emitting diodes (WOLEDs). But it is not easy to simultaneously combine these characteristics into WOLEDs. Herein, efficient and color-stable WOLEDs with double light-emitting layer are constructed. The double light-emitting layer structure is composed of a red-green (RG) emitting light which originate from incomplete energy transfer from the host of tris-(8-hydroxyquinolinato)aluminum (Alq3) to guest of 4-(Dicyanomethylene)-2-tert-butyl-6-(1,1,7,7-tetramethyljulolidin-4-yl-vinyl)−4 H -pyran (DCJTB), and a blue-green emitting light from ( E )-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-1-yl)anthracene (APEAn1N). In these WOLEDs, the different doping concentrations of DCJTB in Alq3 were optimized. Finally, a WOLEDs with relatively simple preparation was obtained with a maximum brightness of 9296 cd m −2 , maximum current efficiency (CE) of 10.17 cd A −1 , maximum power efficiency (PE) of 5.80 lm W −1 , maximum external quantum efficiency (EQE) of 4.09%, Commission Internationale de L'Eclairage (CIE) coordinate of (0.41, 0.46) and color rendering index (CRI) of 75 (85), respectively. And the chromaticity coordinate is stable at (0.41, 0.46) with increasing operation voltage. These results reveal that the fluorescent WOLEDs possess simplified fabrication, low cost, relatively high efficiency, acceptable CRI and stable color, simultaneously. [ABSTRACT FROM AUTHOR]

Typical π-π 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-10 H-spiro[acridine-9,9′-fluoren]-2-yl)phenyl)-1 H-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 ( Tg) of 198 °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 448 nm, maximum luminance of 2122 cd m−2, maximum current efficiency (CE) of 3.97 cd A−1, and a maximum power efficiency of 2.08 lm W−1. The chromaticity coordinate is stable at (0.15, 0.10) at the voltage of 7-11 V. The device shows a slow efficiency roll-off with CE of 3.35 and 2.85 cd A−1 at 100 and 1000 cd m−2, respectively. [ABSTRACT FROM AUTHOR]