A Single Phosphine Oxide Host for High-Efficiency White Organic Light-Emitting Diodes with Extremely Low Operating Voltages and Reduced Efficiency Roll-Off

Highly efficient white organic light-emitting diodes (WOLEDs) with a simple, single-host-based structure are fabricated to realize the state-of-the-art performance of extremely low driving voltages, high efficiencies, and low efficiency roll-offs. This is the first single-host-based WOLED with both high efficiency and extremely low operating voltage at practical luminescence, demonstrating the great potential of these WOLEDs for portable display and lighting applications.