Synthesis, structural refinement and luminescence properties of green-emitting Gd₃GaO₆:Tb³⁺ phosphors for display...

Green-emitting Tb³⁺-doped Gd₃GaO₆ phosphors were fabricated through a low-temperature solution-combustion approach utilizing urea as the fuel. Powder XRD analysis suggested an orthorhombic structure with the Cmc2₁ space group. Crystallite size was determined using the Scherrer's formula and W-H plot. Surface topography was examined utilizing the FESEM technique, and EDX data confirmed the uniform incorporation of Tb³⁺ ions into the Gd₃GaO₆ lattice with proper stoichiometry. A bright green emission was exhibited by phosphors at 543 nm, attributed to the ⁵D₄ → ⁷F₅ transition upon irradiation with near ultraviolet light at 272 nm. The observed concentration quenching at 3 mol% Tb³⁺ in the Gd₃GaO₆ matrix was attributed to non-radiative energy transfer between the neighbouring Tb³⁺ ions, which became significant at higher doping levels. The quenching observed beyond the optimum concentration is primarily attributed to dipole-dipole interactions between adjacent Tb³⁺ ions. The CIE chromaticity coordinates are located the green region, and the calculated CCT value (4500-5500 K) lies in the cool temperature range, making this phosphor a suitable candidate for cool white-solid state lighting and display devices.