Visible emission studies of samarium doped Ca₂Ga₂SiO₇ phosphor for luminescent device applications

A series of Ca₂Ga₂SiO₇ phosphors doped with variable amounts of samarium ions (Sm³⁺) were synthesized by the solid-state reaction method. XRD analysis validates the formation of a pure phase, while SEM demonstrates homogenous particle structure with irregular morphology in the Sm³⁺ doped Ca₂Ga₂SiO₇ (CGS) phosphor. CGS phosphors exhibited emission centered at 563, 599, and 646 nm, which corresponds to the transitions ⁴G₅_/₂ → ⁶H_j (J = 5/2, 7/2, and 9/2) of the Sm³⁺ ions under n-UV excitation of 401 nm. The interaction between Sm³⁺ ions was primarily dipole-dipole, as confirmed by Dexter’s theory and the Inokuti-Hirayama model. The decay curve analysis exhibited that the optimized phosphor had a lifetime of 2.11 ms. The chromaticity coordinates for this optimized phosphor, calculated according to the Commission Internationale de l’Eclairage (CIE) standards, were (0.579, 0.413), indicating a pure orange emission. These results propose that this phosphor is a strong candidate for application in solid-state lighting.