Highly efficient white organic light-emitting diodes using two emitting materials for three primary colors (red, green, and blue)

The authors have demonstrated highly efficient white organic light-emitting diodes (WOLEDs) by using two emissive materials as a dopant, 1,4-bis[2-(⁠$7-N$-diphenyamino-2-(9,9-diethyl-$9H$-fluoren-2-yl)) vinyl] benzene (DAF-ph) and iridium(III) bis(5-acetyl-2-phenylpyridinato-$N,C2′$⁠) acetylacetonate $((acppy)2Ir(acac))$⁠. It was found that the OLED fabricated in this study emitted a white color consisting of three primary colors (red, green, and blue). The luminance-voltage $(L-V)$ characteristics of the WOLEDs showed the maximum luminance of $30500cd∕m2$ at $14V$ and the maximum luminous efficiency of $38.0cd∕A$⁠, respectively. The $CIEx,y$ coordinates of the WOLED also showed (⁠$x=0.33$⁠, $y=0.40$⁠) at $10V$⁠.