Performance of Inverted Quantum Dot Light-Emitting Diodes Enhanced by Using Phosphorescent Molecules as Exciton Harvesters

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• 作者：Guohong Liu ; Xiang Zhou ; Xiaowei Sun ; Shuming Chen
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：March 3, 2016
• 年：2016
• 卷：120
• 期：8
• 页码：4667-4672
• 全文大小：434K
• ISSN：1932-7455

文摘

Exciton harvesters based on blue phosphorescent molecules bis(4,6-difluorophenylpyridinato-N,C2)picolinatoiridium (FIrpic) doped in 4,4′,4″-tris(carbazol-9-yl)triphenylamine (TCTA) are used to enhance the performance of inverted quantum dot light-emitting diodes (QD-LEDs). In the proposed device structures, electrons that leak to the TCTA layer can be effectively captured by FIrpic and subsequently can recombine in the TCTA:FIrpic layer. The harvested energy is then nonradiatively transferred to the adjacent QDs via Förster dipole–dipole coupling mechanism. Because of effective harvest of leaked electrons and complete energy transfer from FIrpic to the adjacent QDs, the demonstrated QD-LEDs exhibit pure QD emission, higher efficiency (1.62-fold improvement), and longer lifetime.