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Blue organic light-emitting diodes (OLEDs) are of great significance in the fields of flat-panel display and solid-state lighting. Herein, three carbazolyl-substituted blue emitters, namely SAF-CzB , SAF-2CzB , and F-2CzB , were designed and synthesized. Two compounds SAF-CzB and SAF-2CzB possess a rigid spiro[acridine-9,9′-fluorene] (SAF) central core. The counterpart F-2CzB , which contains 9,9-dimethylfluorene as core was, also researched for comparative purpose. The introduction of SAF into fluorene-based materials could simultaneously improve their thermal stability, hole injection and transport ability, as well as prevent the fluorenone defect. The compound SAF-2CzB shows a higher decomposition temperature ( T d ) of 534 °C compared to that of F-2CzB (488 °C). The hole-transporting property of SAF-2CzB is also better than that of F-2CzB demonstrated by single-carrier devices. The presence of a bulky spiro-annulated triphenylamine moiety at the C9 position of the fluorene might suppress the fluorenone defect. Non-doped OLED based on SAF-2CzB as the emitting layer shows the best performance with maximum current efficiency (CE) of 4.07 cd A −1 and power efficiency (PE) of 1.83 l m W −1 , compared with 3.03 cd A −1 and 1.08 l m W −1 for SAF-CzB , 3.14 cd A −1 and 1.23 l m W −1 for F-2CzB . In particular, both SAF-2CzB - and F-2CzB -based device exhibit good color stability with CIE coordinate of (0.16, 0.11) at the voltage of 7–12 V. [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]

1-(9-Anthryl)-2-phenylethene ( t -APE) is a blue-green material with high fluorescence quantum yield ( Ф f 0.44). However, it is easily crystallized. Herein, Two asymmetric blue-green emitting materials based on t -APE, ( E )-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-1-yl)anthracene ( 6 ) and ( E )-9-(4-(2-(anthracen-9-yl)vinyl)phenyl)-10-(naphthalen-2-yl)anthracene ( 7 ) were firstly designed and synthesized. The two compounds possess high thermal stability, morphological durability, and bipolar characteristics. The non-doped blue-green organic light-emitting diodes (OLEDs) using 6 and 7 as emitting layers showed emission at 495 nm, full width at half maximum of 80 nm, maximum brightness of 13,814, 10,579 cd m −2 , maximum current efficiency of 3.62, 7.16 cd A −1 , and Commission Internationale de L'Eclairage (CIE) coordinate of (0.20, 0.43), respectively. Furthermore, when employing 6 and 7 as blue-green emitting layers and rubrene doped in tris-(8-hydroxyquinolinato)aluminum (Alq3) as the orange emitting layers to fabricate white OLEDs (WOLEDs), the WOLEDs exhibit a maximum brightness of 10,984, 14,652 cd m −2 , maximum current efficiency of 2.04, 2.70 cd A −1 , and CIE coordinate of (0.30, 0.40), (0.37, 0.47), Color Rendering Index (CRI) of 65, 60, stable EL spectra, respectively. This study demonstrates that the t -APE-type derivatives have the excellent properties for the emitting materials of OLEDs. [ABSTRACT FROM AUTHOR]

Herein, the organic blue emitting material (E)-4-(4-(anthracen-9-yl)styryl)- N , N -diphenylaniline (AnStDPA) with D–π–A chromophore was synthesized. The thermal, optical, electrochemical properties and the device performance of the AnStDPA were investigated. The AnStDPA shows high thermal stability with decomposition temperature (T d , 5% weight loss) value of 319 °C, high photoluminescence quantum yield (PLQY) with value of 0.92 and no thermal fluorescence quenching property. The HOMO and LUMO level of AnStDPA are −5.44 eV and −2.60 eV, respectively. When using AnStDPA to construct organic/inorganic hybrid LED, the LED exhibits blue emission, stable Commission Internationale de L'Eclairage (CIE) chromaticity coordinate of (0.1522,0.0895) and tranquil luminance efficiency of 10 lm W−1 (around) at various currents. In addition, the phosphor-free hybrid WLEDs based on AnStDPA and Rubrene (5,6,11,12-tetraphenylnaphthacene) were prepared. The device possesses luminance efficiency of 27.70 lm W−1 (at 19.90 mA), CCT of 4363 K, Ra of 65.2, and CIE chromaticity coordinate of (0.3471, 0.2750). Moreover, there is almost no ultraviolet (UV) residue in these hybrid LEDs based on the AnStDPA. We have simultaneously achieved organic/inorganic hybrid blue LED (based on near UV chip) with almost no UV residue and spectral stability. • The AnStDPA possesses high PLQY and no thermal fluorescence quenching property. • The spectral overlap between the absorption of AnStDPA and emission from NUV chip. • The CIE of the blue hybrid LED based on AnStDPA is stable at various currents. • The phosphor-free hybrid WLED based on AnStDPA and Rubrene was studied. • There is almost no UV residue in these hybrid LEDs based on the AnStDPA. [ABSTRACT FROM AUTHOR]