Highly efficient solution-processed white OLEDs via TADF host-sensitized dinuclear platinum (III) complex

Abstract

External quantum efficiency (EQE), color rendering index (CRI), color correlated temperature (CCT), and spectral stability are key challenges for constructing high-performance white organic light-emitting diodes (WOLEDs) with a simple device structure. Herein, in order to resolve these issues, we primarily employed a thermally activated delayed fluorescence (TADF) emitter of CzAcSF as a host emitter and a dinuclear platinum (III) complex (Pt-1) as a guest emitter to construct solution-processed single-emitting layer WOLEDs at low guest concentrations of 0.75–1.50 wt. %. Thanks to their broad coverage of visible spectra, efficient energy transfer, and weak charge trap of Pt-1, the optimized WOLEDs showed an increasing EQE of 11.93% and a current efficiency of 30.76 cd/A with a high CRI of 75 and a CCT of 5210 K. Furthermore, the stable electroluminescent spectra with CIE (commission internationale de L'Eclairage) coordinate deviations of Δx = 0.022 and Δy = 0.015 were exhibited. This is an outstanding example for high-performance WOLEDs via employing a TADF host-sensitized low-concentration dinuclear platinum (III) complex simultaneously with high efficiency, CRI, CCT, and color stability.