Construction and Emission Tuning of the One-Dimensional (MBI)CdCl₄·H₂O toward Anti-Counterfeiting and Information...

Organic-inorganic hybrid metal halides (OIHMHs) have attracted considerable attention because of their superior optoelectronic properties and structural versatility, yet one-dimensional (1D) OIHMHs remain the least studied relative to their 0D, 2D, and 3D counterparts. Here, a new 1D blue-emitting hybrid cadmium chloride phosphor, (MBI)CdCl₄·H₂O, was constructed using 2-methylbenzimidazole (MBI) as the organic ligand. It crystallizes in the monoclinic P2₁/c space group, consisting of distorted [CdCl₆]^4- octahedra connected via edge sharing. Incorporation of Sb³⁺ ions with stereochemically active 5s² lone-pair electrons yields (MBI)Cd_0.7Sb_0.2Cl₄·H₂O, which exhibits highly efficient yellow emission with a photoluminescence quantum yield (PLQY) of 92.0%. In addition, doping with high-spin Mn²⁺ ions produces photoluminescent (MBI)Cd_0.85Mn_0.15Cl₄·H₂O crystals with a PLQY of 16.7%. Leveraging the tunable luminescence of this Cd halide, these materials were further demonstrated in anticounterfeiting and information encryption applications, highlighting a promising avenue for the development of functional metal halides.