Highly Efficient Hybridized Local and Charge-Transfer (Hlct) Deep-Blue Electroluminescence with Excellent Molecular Horizontal Orientation

Efficient deep-blue emitters with nice color purity are fundamental in organic light-emitting diode (OLED) applications. Herein, we report two phenanthroimidazole (PPI) derivative deep-blue emitters ( DP , SP ) with hybrid local and charge-transfer (HLCT) properties of high photoluminescence quantum yield (PLQY) and nice color purity. More importantly, the horizontal dipole orientation (Θ // ) of them are both superior to the isotropic emitters (66.7%), especially the Θ // of SP is 89.5%, which can greatly improve its OLED performance. As a result, non-doped OLED of SP exhibits deep-blue emission with Commission Internationale de lEclairage (CIE) coordinate of (0.158, 0.068) and maximum external quantum efficiency (EQE max ) of 11.3%, which is nearly twice that of DP and is one of the best results among the non-delayed, non-doped deep-blue fluorescent OLEDs. Furthermore, SP -based doped OLED displays an excellent performance of near ultraviolet (NUV) emission at 406 nm with CIE coordinate of (0.157, 0.046) and EQE max of 7.5%, which is also a competitive result in the materials with comparable NUV OLED applications