Luminescence and site occupancies of Eu3+ in La2CaB10O19

Abstract

Eu³⁺-activated La₂CaB₁₀O₁₉ phosphors with nominal chemical formulae La_2−xEu_xCaB₁₀O₁₉ and La₂Ca_1−2xEu_xNa_xB₁₀O₁₉ were prepared. The luminescence properties under VUV-UV excitation were investigated. Luminescence spectra reveal Eu³⁺ ions occupy both Ca²⁺ and La³⁺ sites in all samples. The O²⁻ → Eu³⁺ charge transfer bands (CTBs) and the ⁵D₀ → ⁷F₀ emissions of Eu³⁺ at Ca ²⁺ site and La³⁺ site are identified, respectively. The schematic energy levels for Eu³⁺ in two sites were achieved. Luminescence decays of the ⁵D₀ → ⁷F₀ transitions were measured for both sites.