The effect of silver on obtaining pure phase of Eu³⁺-doped Sr₂CeO₄ for white color emission using citrate as precursor

This work focuses on Sr₂CeO₄ materials containing Ag⁺ and Eu³⁺ that are obtained by a combustion method using citric acid as a precursor. The heat-treatment at 1100 °C was efficient and phase impurities are eliminated with presence of Ag⁺, favoring the Sr₂CeO₄ formation, as confirmed by XRD. SEM analysis shows a proportional decrease in the organization of particles as a function of doping material, with a nanorods morphology. Diffuse reflectance shows that materials are transparent at visible region, with absorption at UV region. Exciting Sr₂CeO₄-based materials at 270 nm, photoluminescence analysis reveal a band at 470 nm, characteristic of this material and, incorporating Eu³⁺, emission bands beyond 470 nm are observed characteristic of Eu³⁺. Eu³⁺ photoluminescence makes the Sr₂CeO₄ materials present color coordinates at bluish green, green, white, yellowish pink and reddish orange regions of electromagnetic spectra. Decay lifetimes of Sr₂CeO₄ and Eu³⁺ were determined and are discussed. The results obtained demonstrate materials with a high potential for application in light emitting devices, and a methodology efficient at obtaining these materials.