Luminescence and dosimetry approach in terbium(III)-activated tungstate double perovskite

A series of tungstate double perovskite Ca₃ WO₆ doped with Tb³⁺ was prepared by a combustion process using urea as a flux. The crystal structure identification of Ca₃ WO₆ :Tb³⁺ phosphors was done using X-ray diffraction patterns, and a monoclinic structure was discovered. The Fourier transform infrared spectrum of Ca₃ WO₆ :Tb³⁺ displayed characteristic vibrations of tungstate bonds. Under 278 nm excitation, Ca₃ WO₆ :Tb³⁺ exhibited intense downconversion green emission, which corresponded to the ⁵ D₄ -⁷ F_J (J = 4,5) transitions of Tb³⁺ . The phosphor exhibited the highest photoluminescence (PL) intensity when it was doped with 1 mol% of Tb³⁺ ; later intensity quenching appeared to be due to the multipolar interaction at higher dopant concentrations. Moreover, high-quality thermoluminescence (TL) was detected when phosphors were irradiated using beta rays. The effects of Tb³⁺ concentration and beta dose on TL intensity were the two major aspects studied in detail. The TL intensity demonstrated excellent linear response to the applied range of beta dose. The trap parameters of the studied phosphors were computed by the peak shape approach and glow curve deconvolution. The fading effect on TL intensity was studied by recording the TL glow curves after 1 month of beta irradiation. Obtained results from the PL and TL characterizations showed that the phosphors under study have the potential to be used in lighting displays and in thermoluminescence dosimetry.