Progress on Phenanthroimidazole Derivatives in Blue-Emitting Materials

The impending global energy crisis and inefficient energy utilization have driven the use of energy efficient devices for display and lighting applications. Energy-efficient organic light emitting diodes (OLEDs) are considered to be the next generation of smart displays, becoming one of the most competitive candidate for future energy-efficient lighting sources. The molecular design of high-efficiency deep blue materials are greatly limited due to their inherent wide bandgap, poor carrier charge balance and their low efficiency in the solid state. As a novel building block for blue-emitting materials, phenanthroimidazole (PI) group is attractive stems from their bipolar feature and excellent fluorescence efficiency, which has aroused strong interest of researchers. Molecular design and photophysical properties of phenanthroimidazole-based deep blue-emitting materials are of great significance. In this review, an overview of the recent studies on PI-based blue emitters for applications in organic light-emitting diodes (OLEDs) is presented. The luminescence mechanism, design and latest developments of the electroluminescent devices fabricated from phenanthroimidazole derivatives are described, and their prospects in the future of full-color display and solid-state lighting are forecasted.