High‐Performance Quantum Dot Light‐Emitting Diodes Based on Self‐Assembled Ordered Monolayer Quantum Dots Film at Air‐Liquid Interface

ABSTRACT

A high‐quality quantum dots (QDs) layer is crucial for the commercialization of quantum dot light‐emitting diode (QLED) devices. However, current fabrication techniques cannot simultaneously achieve monolayer coverage, ordered arrangement, and large‐area scalability. Herein, we develop a novel strategy of continuous stepwise self‐assembly for QDs monolayer integrated the air‐liquid interfacial assembly technology with continuous line‐ink‐supply and Langmuir‐Schaefer (LS) technology, which the QDs can be finely to assemble into large area ordered and dense QDs monolayer film at the trailing edge of the flow. The ordered QD monolayers can be repeatedly transferred and stacked to accurately control the thickness of the luminescent layer in QLED devices. Green QLED based on this monolayer film reaches a high EQE of 23.85%. Furthermore, the optimized trilayer device exhibits negligible efficiency roll‐off, retaining an EQE above 18% and a luminous efficacy of 60 lm W ⁻¹ at a luminance of 200 000 cd m ⁻² . This methodology also shows preliminary scalability potential. We achieved a trial fabrication of large‐area QD films of 210 cm ² and further constructed corresponding QLED devices with an emission area of 1.5 cm × 1.5 cm as an initial exploration.