RESUMEN
The Er3+/Yb3+:NaGd(WO4)2 phosphors and the phosphor-in-glass (PIG) have been synthesized employing a typical approach to investigate their structural, morphological and optical properties. Several PIG samples containing different amounts of NaGd(WO4)2 phosphor have been manufactured by sintering the phosphor and glass [TeO2-WO3-ZnO-TiO2] frit together at 550 °C, and its impact on the luminescence characteristics has been extensively studied. It has been noticed that the upconversion (UC) emission spectra of PIG under 980 nm excitation display similar characteristic emission peaks to the phosphors. The maximum absolute sensitivity of the phosphor and PIG is 17.3 × 10-3 K-1 @ 473 K and the maximum value of relative sensitivity is 10.0 × 10-3 K-1 @ 296 K and 10.7 × 10-3 K-1 @ 298 K, respectively. However, thermal resolution at room temperature has been improved in the case of PIG as compared to the NaGd(WO4)2 phosphor. As compared to the Er3+/Yb3+ codoped phosphor and glass, the less thermal quenching of luminescence has been observed in PIG.
RESUMEN
The present article reports the optical absorption and upconversion (UC) studies of 1.0 mol% Er3+/2.0 mol% Yb3+doped/codoped glasses prepared by melt-quenching technique. The elements present and the composition of the prepared glass have been confirmed from XPS and XRF analysis respectively. Judd-Ofelt intensity parameters have been calculated using the absorption spectrum which is further utilized to predict the nature of Er_O bond, the transition probabilities, branching ratios and radiative lifetimes. The CIE study shows non-colour tunable and highly pure green emission (94.2%). The temperature-dependent UC emission spectra of the 2.0 mol% Yb3+sensitized glass have been recorded at three different pump power densities to establish a reliable FIR based temperature scale. Furthermore, the Arrhenius fitting of the temperature-dependent spectra reveals low thermal quenching of green luminescence in the codoped glass.