Efficient Multi‐Luminescence Covering the Visible to Near‐Infrared Range in Antimony and Lanthanide Co‐Doped Indium‐Based Zero‐Dimensional Perovskites Nanocrystals

Abstract Doping impurity ions, such as lanthanide (Ln 3+ ) ions, can introduce unique emissions over the visible and near infrared (NIR) region and enrich the optoelectronic properties for lead‐free perovskites. Here, tetragonal Cs 3 InCl 6 :Sb nanocrystals (NCs) with bright self‐trapped excitons (STEs) emission have been synthesized. Interestingly, tetragonal Cs 3 InCl 6 :1%Sb can transform into monoclinic Cs 3 InCl 6 :1%Sb and orthorhombic Cs 2 InCl 5 ·H 2 O:1%Sb under different solvent triggers. Further, a series of Ln 3+ ions are doped into Cs 3 InCl 6 :Sb NCs, along with the appearance of Ln 3+ ions emissions over the visible and NIR region. Benefiting from the different photoluminescence (PL) origins of the STEs and Eu 3+ emissions, Cs 3 InCl 6 :Sb,Eu NCs enable varied color delivery and exhibit great potential as anti‐counterfeiting materials. Meantime, Cs 3 InCl 6 :Sb,Nd NCs with strong NIR emissions demonstrate great potential for NIR light‐emitting diode (LED) applications. This work not only presents an effective strategy to tune the optoelectronic properties of lead‐free perovskites, but also provides insight into applications in the anticounterfeiting and LED fields.