Tandem organic light-emitting devices (OLEDs) have attracted considerable attention for solid-state lighting and flat panel displays because their tandem architecture enables high efficiency and long operational lifetime simultaneously. In the tandem OLED structure, plural light-emitting units (LEUs) are stacked in series through a charge generation layer (CGL) and an electron injection layer (EIL). In this chapter, we focus on the key features of tandem OLEDs for high efficiency and long operational lifetimes. We also demonstrate the effect of the CGL comprising a Lewis acid, an n-type semiconductor metal oxide, and an organic electron-accepting material. We discuss the two types of EILs in tandem OLEDs: alkali metals containing n-type compounds and ultra-thin metals. Finally, we focus on the recent progress of the state-of-the-art solution-processed tandem OLEDs.

中文翻译：

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具有串联结构的有机发光器件。

串联有机发光器件（OLED）在固态照明和平板显示器方面引起了相当大的关注，因为它们的串联体系结构可同时实现高效率和长使用寿命。在串联OLED结构中，多个发光单元（LEU）通过电荷产生层（CGL）和电子注入层（EIL）串联堆叠。在本章中，我们重点介绍串联OLED的关键特性，以实现高效率和长使用寿命。我们还证明了包含路易斯酸，n型半导体金属氧化物和有机电子接受材料的CGL的效果。我们讨论了串联OLED中的两种EIL：包含n型化合物的碱金属和超薄金属。最后，