Quantum dot (QD) luminescent materials are a key component of new display technologies, which have emerged as strategic industries in China, Japan, South Korea, Europe, and the United States. To advance the practical application of high-performance quantum dot light-emitting diodes (QD-LEDs), various research institutes and manufacturers worldwide are exploring different approaches to achieve significant theoretical and technical breakthroughs.
Recently, Professor Liang-Sheng Liao and Associate Professor Ya-Kun Wang from the Institute of Functional Nano & Soft Materials at Soochow University focused on achieving long-range order of perovskite quantum dot films with high conductivity. Through extensive experimental exploration, they proposed a new strategy for surface regulation of QDs. Significant breakthroughs were made in the successful preparation of QD-LEDs with high luminous efficiency and stability. The prepared perovskite QD-LEDs maintain an external quantum efficiency of over 20% at a brightness of 1000 nits, with a stability of operational device increased by more than 100 times, representing the highest recorded so far among perovskite QD-LEDs.
The research group asserts that preparing long-range order QD films is essential for improving exciton utilization and device stability. Previous studies have shown that poor long-range ordering in perovskite QD film inhibits carrier injection due to the large surface-to-volume ratio, resulting in inferior operating stability at high brightness. In response, Liang-Sheng Liao's research group proposed a synergistic dual-ligand approach that in-situ dissolves smaller QDs to regulate size and more efectively removes less conductive ligands to enable long-range ordering, compact, uniform and defect-free film, demonstrating excellent performance in LEDs.
In summary, this work introduces a novel method for the controllable preparation of long-range ordering QD films and achieves the effective integration of high brightness, high efficiency, and high stability in perovskite QDs for the first time. These findings paves the way for the practical application of high-performance quantum dot displays. The relevant results were published online on May 8, 2024, in the journal ‘Nature’. Associate Professor Ya-Kun Wang was the first author, and Professor Liang-Sheng Liao was the corresponding author. Additionally, Professor Sui-Dong Wang's research group assisted with the characterization of film mobility.
Link to paper:https://doi.org/10.1038/s41586-024-07363-7
Title:Long-range order enabled stability in quantum dot light-emitting diodes
Authors:Ya-Kun Wang, Haoyue Wan, Sam Teale,Luke Grater, Feng Zhao, ZhongdaZhang, Hongwei Duan, Muhammad Imran, Shui-Dong Wang, Sjoerd Hoogland, Liang-Sheng Liao*
Acknowledgements:We acknowledge the financial support from the National Natural
Science Foundation of China (NSFC) (62205230 and 62175171), the Suzhou Key Laboratory of Functional Nano and Soft Materials, the Collaborative Innovation Center of Suzhou Nano Science and Technology (CIC-Nano), the 111 Project and the Joint International Research Laboratory of Carbon-Based Functional Materials and Devices. We acknowledge the Sargent group at the University of Toronto for providing access to the experimental facilities. This publication is based, in part, on the work supported by the Natural Sciences and Engineering Research Council of Canada.
Editor: Guo Jia