Highly stable and efficient tandem white light emitting diodes based on efficient electron injection and transport

Abstract

Tandem OLEDs have attracted considerable attention due to their promising potential commercial applications. However, the commercial application of OLEDs is limited by their low efficiency and stability. Here, a device with higher efficiency and long lifetime more than 2 00 000 h is reported by using lithium-doped Bphen/HATCN/TPBI as an intermediate layer. The effective separation and transport of charge in the intermediate layer is the key factor to improve the efficiency by a detailed study on the interface electronic structure. In addition, the metal organic complex layer formed by lithium-doped Bphen not only prevented the crystallization of organic compounds but also improved the lifetime of the devices. It is beneficial to further improve the efficiency and lifetime of organic light-emitting devices.