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

作者：Chen, Hao; Liu, Huijun; Shen, Pingchuan; Zeng, Jiajie; Jiang, Ruming; Fu, Yan; Zhao, Zujin^*; Tang, Ben Zhong

来源：Advanced Optical Materials, 2021, 9(9): 2002019.

DOI：10.1002/adom.202002019

• aggregation&#8208
• enhanced emission
• bipolar carrier transport
• host materials
• organic light&#8208
• emitting diodes
• thermally activated delayed fluorescence

Luminogens with high photoluminescence efficiencies and high triplet (T-1) 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 T-1 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.