Lishuang Wang,Jie Lin,Xingyuan Liu,Sheng Cao,Yunjun Wang,Jialong Zhao,Bingsuo Zou
Because of the wide emission spectrum tunability that ranges from the visible region to the near-infrared, InP-based colloidal quantum dots (QDs) show great promise for use in the next-generation full-color displays and solid-state lighting. The performance-improved InP QD-based light-emitting devices (QLEDs) were fabricated by using Mg-doped ZnO nanoparticles (ZnMgO NPs) as an interlayer between the ZnO electron transport layer and active InP QD layer. It is found that ZnMgO NPs can reduce electron injection and suppress exciton quenching, which are attributed to the improvement of charge balance in the devices. We successfully demonstrated higher maximum current efficiencies of 5.46 and 5.91 cd/A than the references (2.31 and 2.36 cd/A) without the ZnMgO NP layer in highly efficient red and green QLEDs, respectively. These results signify an effective approach to improve heavy-metal-free QLEDs for commercial applications.
Yanfang Ren,Yunqi Wang,Yan Fang,Xiaohong Jiang,Meng Li,Ke Cheng,Zuliang Du
The Zinc-Magnesium oxide (ZnMgO, ZMO) nanoparticles (NPs) are well-documented as electron transport layer (ETL) in quantum dot light-emitting diodes (QLEDs). However, ZnO/ZMO nanoparticles prepared via low-temperature sol–gel methods with small grain size and abundant surface defects always suffer from structural and electrical drift, causing lifespan reduction and performance fluctuations of devices. Herein, the benzyl phosphate (BPA) and its derivatives are introduced onto the surface of ZMO NPs as armor layer to stabilize and regulate their properties as ETLs. The prepared ZMO capped with BPA NPs have fine structural and electrical properties stability, which have simultaneously achieves effective defect passivation, enhances nanoparticle dispersibility and stability, and precisely tunes energy levels to balance charge injection. By benefiting from the robust ZMO ETLs, the overall performance of the QLED devices has been greatly boosted. The resulting external quantum efficiency (EQE) of green QLEDs is increased from 20.8% to 29.9%, showing the best performance among currently reported ZMO-based green QLEDs, and over 3.3-fold improvement in T 95 operation lifetime at 1000 cd m − 2 . The relevant physical mechanism has also been investigated. Current work will inspire the exploration of ZMO decorating engineering to construct solution-processed QLEDs device with higher performance.
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