Enhanced upconversion and downshifting emissions from Tb³⁺, Yb³⁺co-doped CaZrO₃phosphor in presence of Li⁺ions

This paper reports the enhanced green photoluminescence from Tb³⁺, Yb³⁺co-doped CaZrO₃phosphor in the presence of Li⁺ion synthesized through solid state reaction technique. The structural studies show an increase in the particle size and a shrink in crystal lattice due to Li⁺co-doping in the phosphor. The phosphor sample emits intense green upconversion emission (UC) due to Tb³⁺ions on excitation with 980 nm radiation which is further enhanced ∼28 times on Li⁺co-doping. The lifetime of⁵D₄level of Tb³⁺ion decreases in the presence of Li⁺ions due to increase in asymmetry in crystal field. The downshifting (DS) emission intensity monitored on 378 and 487 nm excitations is also enhanced in the presence of Li⁺ions. Thus, the Tb³⁺, Yb³⁺, Li⁺co-doped CaZrO₃phosphor can be a suitable candidate for UC solid state lighting.