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Title Improving Efficiency of Top-emission Quantum Dot Light-emitting Diodes Featuring Zn0.9Mg0.1O Nanoparticles used as an Electron Transport Layer
Authors (Gyeong-Pil Jang) ; (Ji-Hun Yang) ; (Su-Young Kim) ; (Young-Bin Chae) ; (Hyuk-Doo Choi) ; (Dae-Gyu Moon) ; (Kyoung-Ho Lee) ; (Chang-Kyo Kim)
DOI https://doi.org/10.5573/JSTS.2024.24.3.259
Page pp.259-269
ISSN 1598-1657
Keywords Quantum dot light-emitting diode; Zn0.9Mg0.1O nanoparticles; electron transport layer; charge balance; exciton quenching
Abstract Zn0.9Mg0.1O nanoparticles (NPs) were employed as electron transport layers (ETLs) with varying thickness, and the effects thereof on the efficiency of top-emission quantum dot light-emitting diodes (TE-QLEDs) fabricated inside a bank were investigated. Increasing the thickness of the Zn0.9Mg0.1O NP ETL led to reduction in oxygen vacancies, resulting in decreased conductivity and current density of the TE-QLEDs. This reduction in conductivity was confirmed by electron-only device (EOD) characteri-zation. At a Zn0.9Mg0.1O NP ETL thickness of 30 nm, the hydroxide oxygen concentration reached a minimal, minimizing exciton quenching at the quantum dot (QD) and Zn0.9Mg0.1O NP ETL interface and thus enhancing the QD charge balance, significantly improving TE-QLED efficiency. A TE-QLED with a 30-nm-thick Zn0.9Mg0.1O NP ETL exhibited outstanding performance, with a maximum current efficiency of 90.92 cd/A and a top external quantum efficiency of 21.66%. These findings underscore the critical role of Zn0.9Mg0.1O NP ETL thickness in suppressing exciton quenching and optimizing charge balance for enhanced TE-QLED performance.