Novel Blue Fluorophor with High Triplet Energy Level for High Performance Single-Emitting-Layer Fluorescence and Phosphorescence Hybrid White Organic Light-Emitting Diodes

On the basis of a D-π-A structural strategy incorporating diphenylamine as an electron-donor and 1,3,5-triazine as an electron-acceptor with a short benzene π-conjugated feature, 4-(4,6-diphenoxy-1,3,5-triazin-2-yl)-N,N-diphenylaniline (POTA), a novel blue fluorophor with high triplet energy level has been designed and synthesized to achieve high performance single-emitting-layer (single-EML) fluorescence and phosphorescence hybrid white organic light-emitting diodes (F–P hybrid WOLEDs). POTA exhibits efficient blue electrofluorescence and excellent host features for green and red phosphorescent devices. The single-EML RGB F–P hybrid WOLED based on POTA and green/red complexes shows a maximum total power efficiency of 59.8 ± 1.0 lm W–1 and a maximum total external quantum efficiency of 24.7 ± 0.7%, representing the highest efficiencies among single-EML RGB WOLEDs. Moreover, these performances are comparable with multiple-EML RGB WOLEDs even based on p-i-n structures, providing verification of the high performance and simple structure of single-EML RGB F–P hybrid WOLEDs.