Crystal structure characterization and up-conversion luminescent properties of BaIn2O4 phosphor

Er³⁺ / Yb³⁺ doped BaIn₂O₄ up-conversion (UC) phosphors are synthesized and their UC luminescent properties are characterized. BaIn₂O₄ has P21/c space group but Rietveld refinement suggests it has twice smaller cell parameter (a = 10.3975 Å, b = 5.8295 Å, c = 14.4457 Å) and volume than previous reported structure. Refinement also reveals Er³⁺/Yb³⁺ replaces In³⁺ ions in lattice because of the existence of InO₆ octahedra. In these BaIn₂O₄ phosphors, co-doping with Yb³⁺ ions changes the predominant UC emission from green ( ²H_11/2, ⁴S_3/2 → ⁴I_15/2 of Er³⁺) to red (about 665 nm, ⁴F_9/2 → ⁴I_15/2 of Er³⁺). By controlling of Er³⁺/Yb³⁺ concentrations, the BaIn₂O₄ phosphors have the potential of generating various UC spectra and color tunability. The pumping powers study shows two-photon process in these phosphors.