Organic light-emitting diodes using potassium chloride as efficiency and stability enhancers

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• 作者：Zhaoyue Lü ; Zhenbo Deng ; Jianjie Zheng ; Enyu Zhou ; Zheng Chen ; Denghui Xu ; Yongsheng Wang
• 关键词：Organic light-emitting diode ; Potassium chloride ; Efficiency enhancer ; Stability enhancer ; Trap site
• 刊名：Displays
• 出版年：2010
• 出版时间：January 2010
• 年：2010
• 卷：31
• 期：1
• 页码：54-58
• 全文大小：778 K

文摘

A multilayer organic light-emitting diode (OLED) has been fabricated with a thin (1 nm) potassium chloride (KCl) layer inserted inside an electron transport layer (ETL), tris (8-hydroxyquinoline) aluminum (Alq₃). The structure of device was ITO/NPB/Alq₃/KCl/Alq₃/Al. The KCl layer was inserted inside 60 nm Alq₃ at 10, 20 and 30 nm positions away from the Alq₃/Al interface. The device shows the optical power and electroluminescence (EL) efficiency enhancements. The highest optical power density of devices with KCl at different positions is more than twice as high as that of the device without KCl. The EL efficiency is enhanced by more than 50 % by inserting the thin KCl insulating layer. The mechanism of KCl EL efficiency enhancer is that the thin KCl layer induces carrier trap sites and gives better recombination in the device. After air-exposure 42 h, the efficiency of the devices with KCl is enhanced but not for the device without KCl. The insertion of KCl inside Alq₃ may improve the stability of OLED.