Synthesis and assessment of photoluminescent properties of Ca4−2xAl6WO16:REx,Nax (RE = Eu3+, Dy3+ and Sm3+) phosphors

Abstract

In the present work, rare earth (Eu³⁺, Dy³⁺ and Sm³⁺) activated Ca₄Al₆WO₁₆ phosphors were synthesized by citrate complexation and combustion methods and their photoluminescence characterization was performed. The phase purity and morphology of the phosphors were characterized by XRD and SEM. The SEM micrographs of phosphor sample synthesized by citrate complexation method show a layer structure while sample synthesized by citrate combustion method show porous nature. Intense red emission of Eu³⁺ and yellow emission of Dy³⁺ in Ca₄Al₆WO₁₆ host lattice show the occupation of a noncentrosymmetric site by the rare earth ions in the host lattice. The reddish orange emission from Sm³⁺ activated phosphor consists of three intense emission peaks in yellow, orange-red and red regions, respectively at 567, 604 and 650 nm. Intense characteristic emissions show no concentration quenching up to 2 mol% concentration of rare earth ions. The phosphors could be effectively excited by near UV (Dy³⁺ activated phosphor) and visible light (Eu³⁺ and Sm³⁺ activated phosphors) and give emission hues from orange-red to near white, demonstrating their potential suitability for application in solid state lighting.