Structural and optical characteristics of green-emitting BaGd2ZnO5:Tb3+phosphor for LED applications

Green-emitting BaGd2-xZnO5:xTb3+ (x = 0-6 mol%) phosphors were synthesized via a high-temperature solidstate reaction. X-ray powder diffraction patterns were used to analyze the phase and structural information of the synthesized phosphors. The surface morphology and elemental composition of the synthesized phosphors were determined using scanning electron microscopy and energy dispersive spectroscopy. The compositional identification and homogeneity of different charges were performed by employing time-of-flight secondary ion mass spectroscopy. An inference regarding the influence of doping on the optical properties of the phosphors was obtained through absorption measurements in the reflectance mode. It was observed that the incorporation of the Tb3+ ions enhances host absorption. The green emission was derived from 5D4 -> 7FJ (J = 3-6) transitions of the Tb3+ ion at an excitation wavelength of 293 nm. Green emission was further verified, using the Commission Internationale del'Eclairage chromaticity diagram, and it was found that the emission coordinates for all the doping concentrations resided in the green region, with colour purity ranging between 80 and 82%. The results suggest that the synthesized phosphors are beneficial for different light-emitting diode applications, especially for ultraviolet phosphor materials.