Figure 5.

Design route and applications of ML materials in mixed anion compounds

(A-i) Formation of local asymmetry, e.g., C₄ or C₃ through replacing one and three ligands by other anion species. (A-ii) An overall noncentrosymmetric structure constructed by periodically aligned mixed anion polyhedrons. (A-iii) Creation of multi-color ML by doping various luminescent centers in mixed anion compounds.

(B) Multiband ML spectra covering the whole VIS-NIR region in Ln³⁺- or Mn²⁺-doped SrZnSO.

(C) Various applications of multi-color ML materials. The VIS ML materials can be applied to a conventional dark-field stress sensing. The NIR ML materials offer an advanced stress sensing approach operable under the natural light (bright-field sensing). Reproduced with permission from (Chen et al., 2020). Copyright 2019 Elsevier.