Analyzing the photoluminescence and energy transfer in Sr₃Gd(BO₃)₃:inorganic borate-based phosphor Eu³⁺, Tb³⁺ and Ce³⁺

Boric acid, urea, and rare-earth nitrates were the starting materials used in the solution-combustion process to create Sr₃Gd_1−X(BO₃)₃:X(M), where M = Eu³⁺, Tb³⁺ phosphors. FTIR, scanning electron microscopy (SEM/EDS), and X-ray diffraction (XRD) were used to examine the morphology and crystal structure. A produced material’s XRD diffraction peaks match Ba₃Dy(BO₃)₃ (JCPDS No. 50-0098). Photoluminescence analysis of Sr₃Gd_1−X(BO₃)₃:X(Tb³⁺) material reveals three emission lines of ⁵D₄ → ⁷F_J (J = 3, 4, 5) at 495, 543, and 587 nm. Of these, the high-intensity green (543 nm) line is produced under the excitation at 352 nm by the electric-dipole and magnetic-dipole induced transition ⁵D₄ → ⁷F₅. Because concentration quenching happens at normal temperature, the optimal concentration of Tb³⁺ in phosphor is found at 3 mol%. Under NUV excitation, its CIE-chromaticity coordinates (x = 0.2513, y = 0.7366) show a pure green colour. Under the excitation at 364 nm, Sr₃Gd_1−X(BO₃)₃:X(Eu³⁺) exhibits the characteristic red photoluminescence at 613 nm. A sequence of distinct bands can be seen in the photoluminescence spectrum at 580 nm (⁵D₁ → ⁷F₀), 595 nm (⁵D₁ → ⁷F₁), and 613 nm (⁵D₁ → ⁷F₂). The forced electric dipole transition and the magnetic dipole transition, respectively, produce the strongest emission peaks at 613 nm and 595 nm, respectively. At normal temperature, a doping concentration of 4 mol% weight is ideal for Eu³⁺. Red and green-emitting phosphor Sr₃Gd_1−X(BO₃)₃:X(M), M = Eu³⁺, Tb³⁺, is activated by NUV radiation.