On the Effect of Sensitizing Ions on the Spectral Luminescent Characteristics of the Eu³⁺ Activating Ion in Lanthanum Ortho- and Metaborates

The effect of Tb³⁺ and Bi³⁺ sensitizing ions on the spectral luminescent characteristics of the Eu³⁺ activating ion in lanthanum ortho- and metaborates is studied. The compounds are studied by X-ray diffraction and luminescent spectroscopy. The doping of La_{1 – x}Eu_хBO₃ and La_{1 – x}Eu_х(BO₂)₃ (х = 0.025; 0.05; 0.075; 0.10) with ions Tb³⁺ and Tb³⁺ in combination with Bi₃ is found to enlarge the range of luminescence in the visible region. Moreover, due to energy transfer from Bi³⁺ to Eu³⁺ in lanthanum orthoborates, the integral luminescence intensity (λ_ex ~ 615 nm) grows by ~25% as compared to the samples free from Bi³⁺ (optimal Bi³⁺ concentration is 5 mol %).