Synthesis and optical properties of blue-light excitable BaBiNaTeO₆:Eu³⁺ red-emitting bismuthate phosphors for white LEDs

A series of red-luminescence bismuthate phosphors of double perovskite BaBiNaTeO₆ doped with trivalent europium (Eu³⁺) were prepared by the solid-state diffusion method. The crystal structure and phase purity of the phosphors were analyzed. The photoluminescence (PL) properties of BaBiNaTeO₆:Eu³⁺ were studied in detail. Upon blue light (466 nm) excitation, the powders showed brilliant red light at around 619 nm, and it was attributed to the electric dipole (ED) ⁵D₀ → ⁷F₂ transition of Eu³⁺. The optimal dopant concentration (x) of the as-prepared phosphor was x = 0.60 mol and the concentration quenching mechanism was evaluated as the electric quadrupole–quadrupole interaction. The BaBiNaTeO₆:Eu³⁺ exhibited good thermal stability and the corresponding activation energy (E_a) was obtained to be 0.27 eV. The chromaticity points of phosphors were near the edge of the red region of the Commission Internationale De L’Eclairage (CIE) 1931 chromaticity diagram. As-prepared white LED based on the GaN blue chip exhibited relatively low correlated color temperature (CCT) of 5042.5 K and high color rendering index (CRI) of 91.6. All characterizations suggest that these double perovskite BaBiNaTeO₆:Eu³⁺ red-emitting phosphors have promising applications in illumination and display field based on blue LEDs.