Abstract
Nanoscaled Tb3+-doped Na3Y(PO4)2 phosphors with magnificent color domain have been synthesized via urea-assisted solution combustion process and characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), and photoluminescence (PL) studies. The Rietveld refinement was executed on the XRD data of Na3Y0.96Tb0.04(PO4)2 and showed that the samples were crystallized into a single-phase orthorhombic lattice with space group Pca21(29). Additionally, TEM micrograph, and Debye–Scherrer equation analysis of Na3Y0.96Tb0.04(PO4)2 revealed the occurrence of nanosized phosphor particles in a size domain lying between 25 and 40 nm. Furthermore, to forecast PL of the as-synthesized nanophosphors, their PL emission and excitation spectra were recorded at a wavelength of 374 and 545 nm, respectively. Under the excitation wavelength (at λex = 374 nm), the PL emission spectra of Na3Y(1−x)Tbx(PO4)2 (where x = 0.015–0.06 mol) exhibited the appearance of most intense peak at 545 nm corresponding to 5D4→7F5 (magnetic dipole allowed) transition. Critical concentration for the nanophosphors series was found to be x = 0.04 (4 mol%) and also the critical transfer distance (Rc) was determined to be 21 Å which ultimately depicted the energy transfer mechanism majorly responsible for concentration quenching as quadrupole–quadrupole interactions. Quantum efficiency for the whole series was calculated and intrinsic lifetime (4.03 ms) was also determined using Auzel’s fitting parameters. CIE coordinates (x, y) for series Na3Y1−xTbx(PO4)2 (where x = 0.015–0.05 mol) were also evaluated by MATLAB software and their results showed that the color tunability from bluish to greenish can be achieved simply by changing the concentration of dopant ions. All the as-obtained results suggest that Na3Y1− x(PO4)2:xTb3+ nanophosphors may show their potential usability as a blue-green component in Near-Ultraviolet (NUV)-based WLEDs, and display gadgets.