The origin of emission in strontium magnesium pyrophosphate doped with Dy2O3

This paper reports on the luminescence properties of Dy3+-doped 30SrO-30MgO-40P2O5, which had been prepared by solid state reaction. The crystalline phases were identified using X-ray diffraction (XRD) and their luminescence properties were studied using excitation and emission spectra obtained from photoluminescence spectroscopy. The results of XRD patterns indicate that the prepared sample contain crystalline phase of MgP2O6 and SrMgP2O7. The excitation spectrum of 30SrO-30MgO-40P2O5:Dy3+ consists of broad bands' centre at ∼280, 310 and 400-600 nm associated with defects and vacancies of host material. The other feature of sharp peaks is very similar and belongs to Dy3+ ions. The f-f transitions in the range of 417-475 nm correspond to the transitions from 6H15/2 to 4K17/2 + 4M19/2,21/2 + 4I13/2 + 4F7/2, 4G11/2, 4I15/2 and 4F9/2, in the range of 392 nm to 6P3/2 + 6P5/2, and in the range of 312-370 nm to 4K15/2, 6P7/2 + 4M15/2 and 4I11/2, respectively. The peaks at 482, 465, and 455 nm could be assigned to the transition of 4F9/2 → 6H15/2, 4I15/2 → 6H15/2 and 4G11/2 → 6H15/2 of Dy3+, respectively. Dy3+ has emissions due to the atomic energy levels of itself and emissions due to the acceptor levels of defect sites formed by Dy3+.