Tunable white-light-emitting Sr2−xCaxNb2O7:Pr3+ phosphor by adjusting the concentration of Ca2+ ion

Abstract The photoluminescence (PL) properties of Sr2−xCaxNb2O7:Pr3+ were investigated in this study. The system exhibited three different states when Sr2+ ion was replaced by Ca2+ ion gradually. The excitation spectra showed the absorptions of the charge transfer (CT) transition of NbO 6 7 - and intervalence charge transfer (IVCT) transition of Pr3+ → Nb5+. The transitions from 3H4 to 3PJ (J = 0, 1, and 2) of Pr3+ were located at 452, 474, and 490 nm. The main excitation peak changed with the phase transformations. The PL spectra of Sr2−xCaxNb2O7:Pr3+ excited with 320 nm showed two intense regions in the wavelength of 480–517 nm (blue-green) and 585–640 nm (orange-red). With increasing content of Ca2+ ion, the orange-red band enhanced and the Commission International de l’Echairage (CIE) moved from blue-green to white and then to purple.