Enhanced upconversion luminescence induced by structrual evolution of lanthanum niobate phosphor

A series of Yb3+-Er3+ coactivated La(Nb1-xVx)O4 (0≤x≤1) upconversion (UC) emission phosphors are prepared by high-temperature solid-state reaction method. Experimental results demonstrate that the introduction of V5+ expands and distorts the unit cell volume of LaNbO4, and induces structural transformation of LaNbO4 from Phase 1 with monoclinic fergusonite structure (0