The Strategies for High‐Performance Single‐Emissive‐Layer White Organic Light‐Emitting Diodes

Abstract White organic light‐emitting diodes (WOLEDs) have been regarded as the most promising candidate for full‐color display and solid‐state lighting applications owing to their favorable merits of high efficiency, superior white color balance, simple fabrication, and large‐area manufacturing possibility. Particularly, single‐emissive‐layer WOLEDs (SEL‐WOLEDs) with the reduced structural complexity, lower process cost, and feasible solution processing have drawn particular attentions. Numerous strategies have been proposed in recent years to construct SEL‐WOLEDs with improved device performance. This review focuses on the aspects, including: a) the molecular design methods for achieving a single‐molecule WOLED; b) the energy transfer mechanisms in various multiple‐molecule SEL‐WOLEDs with all‐fluorescence, all‐phosphorescence, and fluorescence‐phosphorescence hybrid structures; c) the combination of exciplex emitters and complementary fluorescent/thermally‐activated delayed fluorescent/phosphorescent emitters to realize SEL‐WOLEDs. Some future prospects on new opportunities and technological challenges in SEL‐WOLEDs are also covered.