A study on the luminescence properties of CaAlBO₄:RE ³⁺ (RE = Ce, Tb, and Eu) phosphors

A series of new phosphors of CaAlBO₄:RE³⁺ (RE = Ce, Tb, Eu) were synthesized by conventional solid-state reactions. The X-ray diffraction data indicate that a pure phase of CaAlBO₄:RE ³⁺ can be successfully obtained. The photoluminescence (PL) spectra, quantum efficiency, and CIE coordinates of CaAlBO₄:RE³⁺ were investigated. The PL and PL excitation spectra indicate that the emission wavelengths of CaAlBO₄:CE³⁺ are 372 and 398 nm (with full width at half maximum of 33 nm) attributed to the 4f⁶5d-4 f ⁷ transition of the Ce³⁺ activator, respectively. CaAlBO₄:Tb³⁺ displays green emission at 483, 543, 584, and 620 nm, while CaAlBO₄:Eu³⁺ shows a dominating emission peak at 621 nm, which is attributed to the Eu^{3+ 5}D ₀ - ⁷F₂ transition. The quantum efficiencies of optimized CaAlBO₄:Ce³⁺, CaAlBO₄:Tb ³⁺, and CaAlBO₄:Eu³⁺ were found to be 43, 21, and 19%, respectively. The phosphors may provide a new kind of luminescent material under UV excitation.