Realizing High Efficiency and High Color Quality for All-Fluorescence White Organic Light-Emitting Diodes by Interlayer-Sensitizing Configuration with Electron-Capturing Agent

Abstract

As a promising next-generation lighting technology, all-fluorescence white organic light-emitting diodes (WOLEDs) have advanced rapidly but still face the formidable challenge of achieving high efficiencies and high color quality simultaneously. Herein, an interlayer sensitization strategy assisted by electron-capturing agent with thermally activated delayed fluorescence (TADF) is proposed for the fabrication of high-performance all-fluorescence WOLEDs. The proof-of-concept three-color devices with an interlayer-sensitizing configuration are designed, and a low concentration of TADF electron-capturing agent is codoped with a red conventional fluorescence (CF) emitter to reduce exciton loss. The major energy transfer from TADF sensitizing layer to red CF emitter combined with the supplementary energy transfer from TADF electron-capturing agent to CF emitter can successfully increase exciton utilization. The synergistic effect endows the three-color all-fluorescence WOLEDs with high efficiencies, high color quality, and improved efficiency stability and operational stability, simultaneously. The resultant WOLEDs successfully attain remarkable external quantum efficiency of 31.0%, outstanding color rendering index of 93 and long operational lifetime. The record-beating comprehensive performances of these WOLEDs strongly demonstrate the great potential of the proposed strategy for the exploration of high-performance all-fluorescence WOLEDs.