Spectral Investigation of Enhanced Orange Emission in Eu3+ Activated LaPO4 Nanophosphors Through Codoping With Na+ and Bi3+ Ions

Abstract Lanthanum phosphate is a well‐known potential host for rare earth activators for phosphor‐converted white LED application. Na + and Bi 3+ codoped Eu 3+ activated LaPO 4 nanophosphor is successfully synthesized using citrate‐based hydrothermal method at ambient condition and confirmed by XRD, EDS and XPS analysis. The excitation spectra of the sample exhibit sharp f‐f characteristics peak of Eu 3+ at 393 nm that is found to be the most dominant. The comparative photoluminescence studies of La 1‐x PO 4 :xEu 3+ ( x = 0.10), La 1‐x‐y PO 4 :xEu 3+ , yNa + ( x = 0.10, y = 0.05), and La 1‐x‐y‐z PO 4 :xEu 3+ , yNa + , zBi 3+ ( x = 0.10, y = z = 0.05) reveal a progressive enhancement of the orange emission from Eu 3+ as Na + and (Na + , Bi 3+ ) ions are incorporated into the LaPO 4 matrix. The dominance of 5 D 0 ‐ 7 F 1 magnetic dipole transition contributing a major part of orange luminescence of the nanophosphors and the symmetric site occupancy of Eu 3+ was justified from the observed trend of in the Judd–Ofelt intensity parameters. The CIE studies confirm the improvement in color purity of emission from 32.5% to 90.6% due to the presence of Na + and Bi 3+ ions.