Chae Young-Bin, Kim Su-Young, Choi Hyuk-Doo, Moon Dae-Gyu, Lee Kyoung-Ho, Kim Chang-Kyo
Department of Electronic Materials, Devices and Equipment Engineering, Soonchunhyang University, Asan 31538, Republic of Korea.
Nanomaterials (Basel). 2024 Jan 26;14(3):266. doi: 10.3390/nano14030266.
Many quantum dot light-emitting diodes (QLEDs) utilize ZnO nanoparticles (NPs) as an electron injection layer (EIL). However, the use of the ZnO NP EIL material often results in a charge imbalance within the quantum dot (QD) emitting layer (EML) and exciton quenching at the interface of the QD EML and ZnO NP EIL. To overcome these challenges, we introduced an arginine (Arg) interlayer (IL) onto the ZnO NP EIL. The Arg IL elevated the work function of ZnO NPs, thereby suppressing electron injection into the QD, leading to an improved charge balance within the QDs. Additionally, the inherent insulating nature of the Arg IL prevented direct contact between QDs and ZnO NPs, reducing exciton quenching and consequently improving device efficiency. An inverted QLED (IQLED) utilizing a 20 nm-thick Arg IL on the ZnO NP EIL exhibited a 2.22-fold increase in current efficiency and a 2.28-fold increase in external quantum efficiency (EQE) compared to an IQLED without an IL. Likewise, the IQLED with a 20 nm-thick Arg IL on the ZnO NP EIL demonstrated a 1.34-fold improvement in current efficiency and a 1.36-fold increase in EQE compared to the IQLED with a 5 nm-thick polyethylenimine IL on ZnO NPs.
许多量子点发光二极管（QLED）利用氧化锌纳米颗粒（ZnO NPs）作为电子注入层（EIL）。然而，使用ZnO NP EIL材料常常导致量子点（QD）发光层（EML）内的电荷失衡以及在QD EML与ZnO NP EIL界面处的激子猝灭。为了克服这些挑战，我们在ZnO NP EIL上引入了精氨酸（Arg）中间层（IL）。Arg IL提高了ZnO NPs的功函数，从而抑制电子注入到QD中，导致QD内的电荷平衡得到改善。此外，Arg IL固有的绝缘性质防止了QD与ZnO NPs直接接触，减少了激子猝灭，从而提高了器件效率。与没有IL的倒置QLED（IQLED）相比，在ZnO NP EIL上使用20 nm厚的Arg IL的IQLED的电流效率提高了2.22倍，外量子效率（EQE）提高了2.28倍。同样，与在ZnO NPs上使用5 nm厚聚乙烯亚胺IL的IQLED相比，在ZnO NP EIL上使用20 nm厚的Arg IL的IQLED的电流效率提高了1.34倍，EQE提高了1.36倍。
