Pure red perovskite LED technology problem has been solved

22 views admin 2025-02-28

On February 20, Nankai University announced the latest research progress of the scientific research team led by Professor Yuan Mingjian of the School of Chemistry, Academician Chen Jun of the Chinese Academy of Sciences, and Researcher Zhang Wei in the field of new perovskite ultra-high-definition display technology. Aiming at the world's difficult problem of poor phase stability of pure red CsPbI3 perovskite quantum dot materials in new perovskite ultra-high-definition display technology, the team took the lead in proposing the "epitaxial heterojunction interface stress control" strategy, and for the first time used the all-solution method to achieve large-scale in-situ controllable preparation of perovskite van der Waals epitaxial heterojunctions, successfully breaking through the dual bottlenecks of material stability and device performance, and developing pure red perovskite electroluminescent devices (LEDs) with high efficiency and high stability, providing key technical support for the development of next-generation ultra-high-definition display technology, marking a major technological breakthrough in this field.

Perovskite materials have unique advantages such as high fluorescence quantum yield, high color purity, and wide color gamut, and are considered to be ideal materials for the next generation of ultra-high-definition display technology. As one of the three primary colors of red, green and blue, pure red perovskite LEDs are crucial to the realization of next-generation ultra-high-definition display systems that meet the Rec. 2100 ultra-wide color gamut standard. However, pure red perovskite LEDs have long been plagued by the problem of poor material stability. CsPbI3 perovskite quantum dots have size-dependent adjustable bandgap luminescence and are ideal materials for realizing pure red perovskite LEDs. However, the intrinsic phase stability of CsPbI3 perovskite is poor, and its bulk material is prone to phase transition at room temperature and transform into a non-optically active phase. What's more serious is that due to the extremely small particle size and extremely large surface energy of CsPbI3 perovskite quantum dots, they can hardly exist stably at room temperature. Therefore, understanding the phase transition mechanism of metastable CsPbI3 perovskite quantum dots, developing new strategies to improve efficient phase stability on this basis, and then realizing pure red perovskite LEDs with both high efficiency and high stability is an inevitable requirement for promoting the application of perovskite luminescent materials in ultra-high-definition displays.

The scientific research team led by Professor Yuan Mingjian, Academician Chen Jun, and Researcher Zhang Wei has long been engaged in the research of high-performance semiconductor photoelectric conversion materials and devices. In the process of continuously exploring efficient and highly stable perovskite photoelectric materials, the research team found that the phase stability of metastable perovskite materials can be significantly enhanced by achieving local lattice distortion of perovskites through lattice stress manipulation. Based on the above findings, the research team used the design and regulation of ligand molecular structure to report for the first time a new strategy for in-situ preparation of perovskite van der Waals epitaxial heterojunctions by a full solution method to improve the phase stability of perovskite quantum dots. Combining spherical aberration-corrected transmission electron microscopy characterization and density functional theory research, the research team revealed for the first time the regulatory mechanism of the interface stress of perovskite epitaxial heterostructures on the lattice structure of perovskite quantum dots.

Studies have shown that lattice distortion induced by interface stress can effectively inhibit the phase transition process of CsPbI3 perovskite quantum dots and significantly improve the stability of the material. The obtained CsPbI3 perovskite quantum dot conductive film has excellent stability and optoelectronic properties. On this basis, the team successfully developed a pure red light perovskite LED with world-class performance and stability, solving the bottleneck problem that has long plagued this field.

Based on the basic discipline of chemistry, this study brings together multidisciplinary forces such as materials, physics, and semiconductor devices, develops advanced transmission electron microscope structure characterization technology, realizes the creation of new materials for perovskite van der Waals epitaxial heterojunction, and overcomes the stability problem of pure red light perovskite LED core materials, which is expected to further promote technological innovation in the ultra-high-definition display industry.

This work was led by Nankai University and completed jointly with 8 domestic and foreign institutions including Beijing Normal University, University of Hong Kong, EPFL, and King Saud University. Nankai University is the first completion unit of the paper and the only corresponding unit.

Doctoral students Wei Keyu and Zhou Dong from the School of Chemistry and distinguished researcher Jiang Yuanzhi are the co-first authors of the paper. Professor Yuan Mingjian, Academician Chen Jun, and Researcher Zhang Wei are the corresponding authors of the paper. Professor Yuan Mingjian is responsible for the overall design of materials and devices, Academician Chen Jun is mainly responsible for the molecular structure design and characterization platform construction, and Researcher Zhang Wei is responsible for transmission electron microscopy characterization.