Up-conversion luminescence performance of Tm3+/Yb3+ co-doped strontium cerate phosphors

Tm3+/Yb3+ co-doped Sr2CeO4 phosphors were fabricated via a high-energy ball milling technique. The structural, morphological, and luminescence characteristics were analyzed by XRD technique, field emission scanning electron microscopy, and up-conversion luminescence spectra, respectively. The structural X-ray diffraction patterns indicate their orthorhombic structure. Under excitation at 975 nm, the up-conversion luminescence spectra of Sr2CeO4:Tm3+/Yb3+ samples with various concentrations of Yb3+ were observed. The phosphor containing 10 mol% Yb3+ ions exhibited optimal up-conversion luminescence. All the samples show emission peaks at 478, 652, and 801 nm, which are assigned to the 1G4 → 3H6, 1G4 → 3F4, and 3H4 → 3H6 transitions of Tm3+. A detailed analysis of the up-conversion mechanisms is proposed based on simplified energy level diagram. The results show that the Sr2CeO4:Tm3+/Yb3+ phosphor has potential application prospects in wide-range and light emitting devices.