Multiple strategies towards high-efficiency white organic light-emitting diodes by the vacuum deposition method

Abstract

White organic light-emitting diodes (WOLEDs) have been regarded as the most promising technology in next-generation solid-state lighting. It is still a challenge to achieve high efficiency, low roll-off, and good stability in WOLEDs towards their practical applications. Meanwhile, simplifying device structure and lowering the cost by the design of material and device are also the hot spots in academic and industrial fields for WOLEDs. In this review, we will first introduce the basic working mechanism and performance evaluation of WOLEDs. Then, the development of WOLEDs will be summarized according to the sequence of all phosphorescent WOLEDs, hybrid WOLEDs, all fluorescent WOLEDs, doping-free WOLEDs, and single-emitter WOLEDs. In particular, doping-free WOLEDs, single-emitter WOLEDs, and WOLEDs containing thermally activated delayed fluorescence (TADF) materials have flourished in the past few years, which will be introduced in detail in this review.