Indolocarbazole-Based Host Compounds for Solution-Processed Tandem OLEDs
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초록
내용
The development of solution-processed phosphorescent tandem organic light-emitting diodes (OLEDs) exhibiting high efficiency is reported. The OLED comprises two light-emitting units (LEUs) connected by an interconnecting unit and employs solution processable materials. One of most difficult tasks in the fabrication of the OLEDs is to form a multilayer structure without dissolving underlayer during coating of upper layer. The developed new host materials exhibit high tolerance to methanol. The upper-layer adjacent to the light-emitting layer consists of ZnO nanoparticles, which could be dispersed in methanol by improving the preparation method. This results in the successful fabrication of a solution-processed tandem OLED comprising two LEUs. The maximum external quantum efficiency (EQE) of the tandem device is 23%, and the EQE is 22% even at a high luminance of 10 000 cd m-2.