Luminescent ZnWO4:Ag Fibers as Flexible Platforms for Smart Radiation Sensitive Textiles

In this study, Ag-doped ZnWO4 fibers were successfully fabricated using a simple, low-cost drawing technique, and their structural, morphological, and optical properties were systematically investigated, with particular emphasis on their response to ionizing radiation. ZnWO4 and ZnWO4:Ag nanopowders were first synthesized via a coprecipitation method and subsequently embedded into a polymeric matrix to form flexible microfibers. X-ray diffraction (XRD) analysis confirmed the formation of a single-phase monoclinic wolframite ZnWO4 structure, while Ag incorporation induced slight peak shifting and reduced crystallinitydue to lattice distortion. Raman spectroscopy further verified the preservation of characteristic WO24− vibrational modes. FESEM observations revealed the successful formation of continuous microfibers with average diameters of approximately 12 μm for pristine ZnWO4 fibers and 15 μm for Ag-doped fibers, with uniformly distributed Ag nanoparticles decorating the fiber surface, as confirmed by EDS and elemental mapping analyses. Optical studies demonstrated a strong emission band centered at ∼ 500 nm in both photoluminescence (PL) and ion beam induced luminescence (IBIL) spectra. Notably, Ag-doped ZnWO4 fibers exhibited significantly enhanced luminescence intensity compared to undoped samples under both UV excitation and 2.2 MeV proton irradiation, attributed to Ag-induced defect states, improved charge carrier trapping, and enhanced radiative recombination. The IBIL intensity was substantially higher than PL due to the higher excitation efficiency of energetic protons. These findings highlight the strong potential of Ag-doped ZnWO4 nanofibers as advanced functional materials for ionizing radiation detection, scintillation devices, and smart textile applications.