Dual-emitting from Bi[formula omitted], Ln[formula omitted] (Ln [formula omitted] Eu, Sm) co-activated Ca[formula omitted]Sb[formula omitted]O[formula omitted] phosphor for optical temperature measurement

Abstract

In this paper, a series of Ca(2−x−y) Sb2O7: xBi3+, yLn3+ (Ln = Eu, Sm) fluorescent powder samples were successfully obtained, which used the traditional high-temperature solid-phase synthesis method in the preparation process. Samples of Ca2Sb2O7: Bi3+, Ln3+ (Ln = Eu, Sm) fluorescent powder samples were structurally and optically characterized​ using X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), photoluminescence excitation spectroscopy and emission spectroscopy, and fluorescence decay measurements. The results show that the prepared Ca(2−x−y) Sb2O7: xBi3+, yLn3+ (Ln = Eu, Sm) samples have an orthogonal spider web structure, which remains unchanged whether Bi3+ is single doped or Bi3+ is co-doped with Ln3+ (Ln = Eu, Sm). Under ultraviolet lamp (λex=340nm) irradiation, Bi3+ doped Ca2Sb2O7 powder shows a wide emission band centered at 435 nm, which is owing to the 3P1→1S0 transition of Bi3+ ion. Therefore, the effect of Bi3+ and Ln3+ (Ln = Eu, Sm) co-doped Ca2Sb2O7 samples on the luminescence intensity of the samples at different concentrations was studied. When the temperature was varied from 293 K to 483 K, the absolute temperature sensitivity (Sa) of doped Bi3+/Eu3+ and Bi3+/Sm3+ phosphors is 0.001K−1 (at 483 K) and 0.02K−1 (at 293 K), respectively, and the relative temperature sensitivity (Sr) is 1.03% K−1 (at 343 K) and 1.19% K−1 (at 293 K), respectively. These results demonstrate that Ca(2−x−y) Sb2O7: xBi3+, yLn3+(Ln = Eu, Sm) phosphors are prospective double emission thermal thermometers.