A novel quinoline derivative containing a phenanthroimidazole moiety: Synthesis, physical properties and light-emitting diodes application

Abstract The deep-blue emitting material 2-(8-(benzyloxy)quinolin-2-yl)-1-phenyl-1H-phenanthro[9,10-d]imidazole (QL-PPI) which contains 8-(Benzyloxy)quinoline core and phenanthroimidazole moiety, has been designed and synthesized. The non-doped OLED using QL-PPI as the emitting layer shows emission at 455 nm, full width at half maximum of 100 nm, maximum brightness of 250 cd m−2, maximum current efficiency of 0.47 cd A−1, and Commission Internationale de L'Eclairage (CIE) coordinate of (0.20, 0.22). Furthermore, the QL-PPI with a slight mass concentration in the silica gel is coated on the near ultraviolet (NUV) chip (380 nm) to prepare the hybrid deep-blue LED device HB1 with a y coordinate = 0.0541. The hybrid WLED device HW1 based on QL-PPI mixed with green phosphor [(Ba, Sr)2SiO4: Eu2+] and red phosphor [(Sr, Ca)2AlSiN3: Eu2+] is prepared. The hybrid WLED exhibits luminance efficiency of 18.05 lm W−1 (at 19.90 mA), Correlated Color Temperature (CCT) of 4580 K, Color Rendering Index (CRI) of 80, and CIE chromaticity coordinate of (0.3571, 0.3562). These results reveal that the QL-PPI can apply both in OLED and the hybrid LED simultaneously. The QL-PPI which used in the hybrid WLED has the potential to reduce reliance on rare-earth metals and improve the CRI of the hybrid WLED.