Defect-mediated color-tunable emission properties of Eu, M Co-doped BaZnSiO4 (M = Ti or Sn)

초록

Defect engineering is an effective strategy for modulating luminescence in oxide phosphors. However, the controlled interplay between intrinsic defect emissions and rare-earth activator emissions remains largely unexplored. This paper reports the defect-mediated color-tunable photoluminescence properties and anti-counterfeiting capabilities of Eu3 + and M-co-doped BaZnSiO4 (BZSO:Eu,M; M = Ti or Sn) phosphors. Under near-ultraviolet (NUV) excitation, the BZSO:Eu,M phosphors exhibit distinct emission colors ranging from light green to orange-red. These emissions arise from the spectral overlap of the characteristic 4f-4 f transitions of Eu3+ ions and the luminescence from intrinsic defect states within the BZSO host. Notably, the relative intensities of these two emissions from different origins can be systematically tuned through selective metal ion co-doping. Ti co-doping was found to suppress defect-related luminescence while enhancing the Eu3+ 4f-4 f transitions. Conversely, Sn co-doping amplified defect-related luminescence but suppressed Eu3+ transitions. By leveraging these composition-dependent properties, this study successfully demonstrates an anti-counterfeiting application capable of encoding and decoding hidden characters. These results highlight defect-state engineering via targeted co-doping as an effective approach for designing multifunctional luminescent materials.

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