Stable All-Fluorescence White Organic Light-Emitting Diodes with High Efficiency and High CRI

White organic light-emitting diodes (WOLEDs) have been regarded as the candidates for next-generation flat-panel displays and solid-state lighting due to their low cost. However, it is still challenging to achieve two-component WOLEDs with high efficiency, high color index (CRI), and long lifetime. Here, high-performance all-fluorescence WOLEDs based on a blue fluorescent emitter and an orange thermally activated delayed fluorescent (TADF) emitter are demonstrated. The optimized all-fluorescence WOLED with two EMLs presents the maximum external quantum efficiency (EQE), current efficiency (CE), and power efficiency (PE) of 23.4%, 40.2 cd A-1, and 33.2 lm W-1, corresponding to a maximum CRI value of 83.1 and Commission Internationale de L'Eclairage (CIE) coordinate of (0.30, 0.31). To further improve the device stability, the all-fluorescence WOLEDs with three EMLs and tandem structure are constructed, respectively. Under the premise of ensuring efficiency, in going from the two-EMLs to the three-EMLs and the tandem structure, the LT50 (time to 50% of the initial luminance) of all-fluorescence WOLEDs increase from 601 to 714 h and 1622 h at an initial luminance of 1000 cd m-2. These strategies and results present new insight into the design of all-fluorescence WOLEDs with high efficiency, high CRI, and extended lifetime. High-performance all-fluorescence white organic light-emitting diodes (WOLEDs) are demonstrated. The WOLED with two emitting layers (EMLs) presents the external quantum efficiency (EQEmax) of 23.4%, with a color index (CRImax) of 83.1. In going from the two-EMLs to the three-EMLs and the tandem structure, the time to 50% of the initial luminance (LT50) increases from 601 to 714 and 1622 h. image