Mg-Doped ZnO Nanoparticle Films as the Interlayer between the ZnO Electron Transport Layer and InP Quantum Dot Layer for Light-Emitting Diodes

Abstract

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.