Improving Efficiency of Top-emission Quantum Dot Light-emitting Diodes Featuring Zn0.9Mg0.1O Nanoparticles used as an Electron Transport Layer

초록

Zn 0.9 Mg 0.1 O 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 Zn 0.9 Mg 0.1 O 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) characterization. At a Zn 0.9 Mg 0.1 O NP ETL thickness of 30 nm, the hydroxide oxygen concentration reached a minimal, minimizing exciton quenching at the quantum dot (QD) and Zn 0.9 Mg 0.1 O NP ETL interface and thus enhancing the QD charge balance, significantly improving TEQLED efficiency. A TE-QLED with a 30-nm-thick Zn 0.9 Mg 0.1 O 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 Zn 0.9 Mg 0.1 O NP ETL thickness in suppressing exciton quenching and optimizing charge balance for enhanced TE-QLED performance.

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