Issue 21, 2024

Blue ZnSeTe quantum dot light-emitting diodes with low efficiency roll-off enabled by an in situ hybridization of ZnMgO nanoparticles and amino alcohol molecules

Abstract

ZnSeTe quantum dots (QDs) have been employed as promising emitters for blue QD-based light-emitting diodes (QLEDs) due to their unique optoelectronic properties and environmental friendliness. However, such QLEDs usually suffer from serious efficiency roll-off primarily stemming from exciton loss at the interface of the QD layer and the ZnMgO (ZMO) electron transport layer (ETL), which remarkably hinders their application in flat-panel displays. Herein, we propose an in situ hybridization strategy that involves the pre-introduction of amino alcohols into the reaction solution. This strategy effectively suppresses the nucleophilic condensation process by facilitating the coordination of ammonium and hydroxyl groups with metal cations (M2+, i.e. Zn2+ and Mg2+). It slows down the growth rate of ZMO nanoparticles (NPs) while simultaneously facilitating M–O coordination, resulting in the synthesis of small-sized and low-defect ZMO NPs. Notably, this in situ hybridization approach not only alleviates emission quenching at the QDs/ETL interface but also elevates the energy level of the ETL for enhancing carrier injection. We further investigated the impact of amino alcohols with varying carbon-chain lengths on the performance of ZMO NPs and the corresponding LED devices. The optimal blue ZnSeTe QLED demonstrates an impressive EQE of 8.6% with only an ∼11% drop when the current density is increased to 200 mA cm−2, and the device operating lifetime extends to over 1300 h. Conversely, the device utilizing traditionally post-treated ZMO NPs as the ETL exhibits 45% efficiency roll-off and device lifetime of merely 190 h.

Graphical abstract: Blue ZnSeTe quantum dot light-emitting diodes with low efficiency roll-off enabled by an in situ hybridization of ZnMgO nanoparticles and amino alcohol molecules

Supplementary files

Article information

Article type
Paper
Submitted
07 Apr 2024
Accepted
01 May 2024
First published
02 May 2024

Nanoscale, 2024,16, 10441-10447

Blue ZnSeTe quantum dot light-emitting diodes with low efficiency roll-off enabled by an in situ hybridization of ZnMgO nanoparticles and amino alcohol molecules

S. Ma, F. Cao, G. Jia, Q. Wu, S. Wang and X. Yang, Nanoscale, 2024, 16, 10441 DOI: 10.1039/D4NR01515K

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