Simplified efficient warm white tandem organic light-emitting devices by ultrathin emitters using energy transfer from exciplexes

Abstract

Abstract To realize energy-saving and environmental green illumination by simplified white organic light-emitting devices (WOLEDs) structure and fabricate process, herein, we successfully fabricate a novel simplified efficient WOLED structure using energy transfer from interface exciplexes to complementary color dyes as undoped ultrathin emissive layers (UEMLs) based on tandem OLEDs structure. (Acetylacetonato)bis[2-(thieno[3,2-c]pyridin-4-yl)phenyl]iridium(III) (PO-01) and iridium(III) bis[(4,6-difluorophenyl)-pyridinato-N,C2′]-picolinate (FIrpic) are applied as yellow and blue UEMLs, respectively. Particularly, the designed WOLED with Commission Internationale De L'Eclairage chromaticity coordinate (0.36, 0.41) obtaining a peak of 41.5 cd/A (EQE = 18.59%) without light out-coupling technology, achieving high current efficiency among reported WOLEDs all emitters applied UEMLs. Moreover, the designed white OLEDs generally emit warm white spectrum with low correlative color temperature of 3686 K–4700 K, which show are available for healthy illumination. Therefore, we believe our work help to further develop ideal simplified WOLEDs structure and fabricate process for energy-conservation and environment-friendly healthy illumination with high efficiency, simplified fabrication, low reagent consumption and cost, simultaneously.