Enhanced red emission and thermal stability of Ca(MoO4)0.8(WO4)0.2:xDy3+, yEu3+ phosphors by charge compensation

Ca(MoO4)0.8(WO4)0.2:xDy3+, yEu3+ samples were successfully synthesized via co-precipitation method. XRD patterns, emission spectra, excitation spectra, decay curves and temperature-dependent emission spectra were adopted to represent the performance of the samples. The results displayed that the samples prepared performed scheelite structure with tetragonal system. Under the excitation of 353 nm, the samples presented strong emission at 487 nm, 573 nm, and 615 nm. The energy transfer of Dy3+ → Eu3+ was found from the excitation spectra, emission spectra and decay curves and its mechanism was discussed. The results suggested the luminescence intensity of the sample Ca0.835(MoO4)0.8(WO4)0.2:0.03Dy3+, 0.08Eu3+ with charge compensation was obviously enhanced to 2.75 times than that of the sample Ca0.89(MoO4)0.8(WO4)0.2:0.03Dy3+, 0.08Eu3+ without charge compensation. The QY of the samples were also been increased by 7.6% via charge compensation. At 523 K, the sample maintained a quite strong emission intensity and exhibited excellent thermal stability. The thermal stability of the samples with charge compensation was greater than that without charge compensation. The maximum relative sensitivity was 0.6% K−1 with Dy3+ concentration being 0.03, Eu3+ concentration being 0.05 at 423 K. Ca(MoO4)0.8(WO4)0.2:xDy3+, yEu3+ were proved to be a luminescence material with great application prospects.