A Promising Multifunctional Deep‐Blue Fluorophor for High‐Performance Monochromatic and Hybrid White OLEDs with Superior Efficiency/Color Stability and Low Efficiency Roll‐Off

Abstract High‐performance deep‐blue fluorescent materials matching the required Commission Internationale de l'Eclairage y coordinate value (CIE y ) of < 0.08 are much‐needed in organic light‐emitting diodes (OLEDs) for realizing the perfect application of full‐color displays. However, deep‐blue fluorophors commonly show unsatisfactory performance due to the intrinsic large bandgap characteristic. Here, the deep‐blue nondoped OLED with the good CIE coordinates of (0.15, 0.07) and external quantum efficiency (EQE) of ≈9% is achieved based on a multifunctional and efficient anthracene‐based fluorophor (2M‐ph‐3CzAnBzt). Using it as a host, the sky‐blue fluorescent OLED realizes the maximum EQE of 9.50%, and keeps as high as 9.27% and 8.56% at 1000 and 5000 cd m −2 . More surprisingly, high‐performance hybrid white OLEDs (WOLEDs) with good color stability and low roll‐off are achieved by using it as the blue emitter. Two‐color WOLED shows the forward‐viewing efficiencies of 20.46%, and 76.80 lm W −1 . The three‐color WOLED emitting a candlelight with the color rendering index of ≥ 82 realizes the maximum EQE of 21.49% and remains 20.80% at 1000 cd m −2 . Such superior electroluminescence performance achieved in these OLEDs ranks among the highest values based on deep‐blue fluorophors with CIE y < 0.08.