Photoluminescence characteristic of Gallate-based red emitting phosphors with high color purity

Eu³⁺-activated R₃GaO₆ (R = Y, Gd) phosphors were prepared in a conventional solid-state reaction and their optical properties were investigated. These compounds exhibit strong red emission under light excitation at 254 nm. The emission spectra are dominated by peaks appearing around 610-630 nm that are induced by the electric dipole transition of ⁵D_o→ ⁷F₂ of Eu³⁺. In addition, the appropriate CIE (Commission Internationale de l'Eclairage) chromaticity coordinates, (x = 0.656, y = 0.336) for Y₃GaO₆ and (x = 0.655, y = 0.334) for Gd₃GaO₆, become closer to the NTSC (National Television System Committee) values. With the optimized activator concentrations, the maximum emission brightness is approximately 80% Of Y₂O₃: Eu³⁺ typical red-emitting phosphor under Hg glow discharge conditions.