A Record Efficiency of 1070 nm Near‐Infrared Light‐Emitting Diodes Based on Cs ₃ La _1−x Nd _x X ₆ Perovskite Nanocrystals

ABSTRACT Lanthanide‐based lead‐free perovskite‐type Cs 3 LnX 6 (Ln = La, Ce…Lu, X = Cl, Br, I) nanocrystalline materials (LCPMs) can achieve photoluminescence from visible to infrared by altering lanthanide ions and demonstrate high photoluminescent quantum yield (PLQY). It is expected that LCPMs can take significant roles in the field of new type nanosized semiconductor and near‐infrared (NIR) light‐emitting diodes (LEDs), which have important application in optical communication, food inspection, night vision, biomedicine, and etc. In this paper, Cs 3 La 1−x Nd x X 6 perovskite nanocrystals (NCs) were systemically prepared by the modified hot‐injection method. By introducing non‐luminescent La 3+ and altering the composition of halogen ions (Cl − , Br − , I − ) and defects modification, efficient energy transfer nearly 100% from self‐trapped excitons to Nd 3+ is achieved, with PLQY of 58.37%. After further APTN modification, it reaches an ultra‐high NIR‐PLQY of 64.65%, which is the optimum in various Nd 3+ ‐containing perovskite materials, to the best of our knowledge. The efficient and stable 1064 nm NIR‐LED is fabricated with a record external quantum efficiency (EQE) of 3.49% for the perovskite‐based LED devices and the extralong T 50 lifetime of 488 min. This work provides new issues for searching new type lanthanide‐based semiconductors and breaking through the limitation of wavelength in perovskite‐based NIR‐LEDs.