Recent advances have been achieved collaboratively by Professor Wang Liang (School of Integrated Circuits) and Professor Yu Weiyong (School of Chemistry and Chemical Engineering) in the research of rare-earth ytterbium (Yb)-doped metal halide perovskite (CsPbCl₃) based near-infrared light-emitting diodes (NIR LEDs). Their findings, entitled “Exciton Localization Engineering in Thermally Evaporated Yb-Doped CsPbCl₃ Near-Infrared Light-Emitting Diodes”, have been published in the internationally renowned journal Advanced Materials(IF: 26.8). Master student Shuo Wang, from the School of Chemistry and Chemical Engineering, contributed as the first author. Professor Liang Wang and Professor Weiyong Yu are identified as the co-corresponding authors of this work.

Near-infrared (NIR) emission underpins biomedical imaging, night vision, and optical communication. Yb³⁺-doped CsPbCl₃has demonstrated ultrahigh photoluminescence quantum yields via quantum cutting, primarily enabled by a singular defect-assisted energy transfer pathway arising from the substitution of Pb²⁺by Yb³⁺. However, whether additional pathways exist to facilitate visible (VIS)-to-NIR conversion thereby further enhance the performance of NIR-emissive devices remains an open and compelling question.

Here, we propose strategic engineering of localized bound excitons (BEs) in thermally evaporated CsPbCl₃:Yb system. Assisted BEs significantly promote energy transfer from CsPbCl₃matrix to Yb dopants, unveiling a previously unknown excitonic energy transfer channel. Atomic-scale characterization combined with first-principles calculations uncovers a BE-driven excitonic transfer mechanism, specifically implicating Cs-vacancy-induced defects in mediating exciton behavior. These insights lead to the fabrication of high-performance NIR-LEDs with an 8.9% external quantum efficiency and 410 mW·Sr^-1·m^-2radiance, marking a breakthrough in thermally evaporated NIR (>950 nm) light-emitting diodes.

This work was supported by the National Key R&D Program of China, the National Natural Science Foundation of China, the Taishan Scholar Foundation of Shandong Province, the Basic and Applied Basic Research Foundation of Guangdong Province, and the Natural Science Foundation of Shandong Province.