Structure and photoluminescence studies of orange-red emitting Y3GaO6:Sm3+ nanophosphors for lighting applications

Abstract

Yttrium gallium oxide, Y₃GaO₆, (YGO) phosphors doped with varying concentrations of Sm³⁺ ions have been synthesized using a solution combustion approach. Various spectroscopic and structural analyses were performed on the prepared phosphors to investigate their structural and optical features. The crystal structures and phase characteristics were calculated via X-ray diffraction (XRD). The orthorhombic phases of the considered materials with the Cmc2₁ space group were confirmed with the help of Rietveld refinement analysis. The morphological features and elemental composition were thoroughly investigated using field emission-scanning electron microscopy (FE-SEM) and energy-dispersive X-ray (EDX) spectroscopy, respectively. Under 406 nm excitation, all Sm³⁺-doped YGO samples exhibited strong orange emission at 610 nm due to the ⁴G_5/2 → ⁶H_7/2 transition. The decay curves showed bi-exponential behavior, indicating the presence of two types of crystallographic sites in the YGO host. A doping concentration of 3 mol% Sm³⁺ ions was found to be optimal, which produced maximum orange emission. Photoluminescence (PL) observations revealed that dipole–dipole interactions were responsible for the concentration quenching phenomenon. The measured color coordinates for all materials lie in the orange-red region of the CIE triangle, making them suitable for lighting applications.