A crystal chemical approach to tuning of emission properties in rare earth doped ternary niobates

Abstract

The photoluminescence (PL) properties of two Dy³⁺ doped ternary niobates, LaNbO₄ and CaNb₂O₆ with fergusonite and columbite structures, respectively are investigated and compared. When the emission line corresponding to electric dipole transition of Dy³⁺ at 574 nm is monitored, an intense band due to host excitation is observed in both LaNbO₄:Dy³⁺ CaNb₂O₆:Dy³⁺ systems indicating host-to-activator energy transfer. The presence of a host emission band at 250–300 nm range under 574 nm excitation indicates that the energy transfer is incomplete. The presence of host lattice emission plays an important role in determining the intensity and spectral response of the phosphor compositions.