Efficient Sky‐Blue Bipolar Delayed Fluorescence Luminogen for High‐Performance Single Emissive Layer WOLEDs

Abstract

AbstractLuminogens with high photoluminescence efficiencies and high triplet (T1) energy levels are desired to achieve high‐performance white organic light‐emitting diodes (WOLEDs). In this work, a sky‐blue luminogen (DCB‐BP‐SFAC) with enhanced delayed fluorescence in aggregated state, bipolar carrier transport ability and high T1 energy level is developed. DCB‐BP‐SFAC exhibits bright sky‐blue electroluminescence (EL) in both non‐doped and doped OLEDs with maximum external quantum efficiencies of 14.8% and 23.5%. DCB‐BP‐SFAC can function as efficient host for green, orange and red phosphorescent materials as well as thermally activated delayed fluorescence emitters with excellent EL performance. In addition, fluorescence/phosphorescence hybrid and all‐fluorescence WOLEDs with a single emissive layer are fabricated by adopting DCB‐BP‐SFAC as emitter and host simultaneously. The all‐fluorescence WOLED shows two‐color warm‐white light with good EL efficiencies of 47.1 cd A−1, 46.2 lm W−1, and 19.1%. The excellent performance of these OLEDs demonstrates the great application potential of DCB‐BP‐SFAC in practical display and lighting devices.