Lanthanide-doped yttrium borate matrices with visible emission for lighting

In this work, we studied the structural, morphological, and spectroscopic properties of yttrium borate materials. The YBO₃, YAl₃(BO₃)₄ (YAB), and Y₂Ba₃B₄O₁₂ crystalline nanopowders studied were prepared by the polymeric precursor method. The materials were doped and co-doped with Eu, Tb, and Tm ions for lighting and display devices. We characterized and analyzed by XRD, HR-TEM, SAED, DRS, Raman, PLE, and PL photoluminescence spectroscopies, and lifetime measurements. The XRD shows that the powders are well crystallized. The diffuse reflectance is greater than 80%. The optical band gap value is between 4.5 and 6 eV. The photoluminescent evaluation demonstrated a strong spectral dependence on the UV excitation, being tunable, activating the blue (Tm³⁺), green (Tb³⁺), and red (Eu³⁺) emissions, useful for RGB devices. The dynamics of energy transfer among ions were evaluated. Finally, Er-doped YAB compounds exhibit an internal quantum yield (iQY) of 88.8%, which is of interest for solid-state lighting systems.