On December 22, the scientific research team led by research fellow Yuan Mingjian and academician Chen Jun of the College of Chemistry, Nankai University, in collaboration with the research group led by professor Edward Sargent of the University of Toronto, tackled the key scientific bottlenecks in the synthesis of high-performance semiconductor quantum dot solids, and developed a new strategy for the preparation of high-performance conductive perovskite quantum dot solid films by means of the rational design of the chemical structure of surface organic ligands, realizing the controllable construction of multi-material perovskite three-primary-color electroluminescence devices of various sizes. The research findings were published in the latest issue of Nature under the title "Synthesis-on-Substrate of Quantum Dot Solids." Nankai University is the first author's affiliation, and research fellow Yuan Mingjian, academician Chen Jun, and professor Edward Sargent are the corresponding authors of the paper. 

The scientific research team led by Yuan Mingjian and Chen Jun has always focused on the research on high-performance semiconductor photoelectric conversion materials and devices. In the process of exploring new solutions to the synthesis of perovskite semiconductor materials for device manufacturing, the research team found that it could effectively induce the transformation of physical and chemical properties such as dimensional information of perovskite materials, electronic band structure, and exciton effect by changing the organic ligand structure. Based on these findings, the research team rationally designed the ligands and creatively implemented a new strategy for the in-situ synthesis-on-substrate of high-quality conductive perovskite quantum dot solid films. Since this strategy can solve the problems such as ligand prone to fall off, and poor optical properties and poor conductivity caused by too many ligands in traditional quantum dot preparation strategy, the synthesized perovskite quantum dot solid films have excellent optical and electrical properties. At the same time, the research team introduced such high-performance perovskite quantum dot solid film into electroluminescent light-emitting diodes, and realized the controllable construction of the three-primary-color electroluminescent light emitting diode with high energy conversion efficiency.

This study is a typical case of realizing the controllable adjustment of physical and chemical properties of semiconductor materials through interdisciplinary means such as optics, condensed matter physics, and semiconductor devices from the perspective of chemistry. This achievement marked a breakthrough for traditional quantum dot synthesis strategies, offering a new principle and method for in-situ synthesis of quantum dot solid films.

High-performance perovskite quantum dot solid-state film and its electroluminescent devices

The reviewers of Nature spoke highly of this study: "This work offers a new paradigm of high universality and precise controllability for the synthesis and application of perovskite quantum dots. More importantly, this strategy achieves this in the form of solid films, which is an indispensable component of electroluminescent device manufacturing. The development of this field was restricted for many years due to a lack of sufficiently small high-quality conductive quantum dot solids. This study has solved this problem in a universal way, marking a major breakthrough in this field!"  

Dr. Jiang Yuanzhi, Sun Changjiu, Dr. Xu Jian and Li Saisai are co-first authors of the paper.

Link to the paper: https://www.nature.com/articles/s41586-022-05486-3 

(Edited and translated by Nankai News Team)