Facile wet chemical route synthesis, characterization and spectroscopic analysis of yttrium-doped lanthanum phosphate nanoparticles

Abstract

Pure and yttrium-doped lanthanum phosphate nanoparticles were successfully prepared through a simple one-step co-precipitation method. The phase, morphology and composition of Y x La1 − x PO4 powders with varying dopant concentration (x = 0.00, 0.01, 0.03, 0.05) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) supplemented with energy dispersive X-ray (EDX) analysis and transmission electron microscopy (TEM). XRD analysis reveals the nanocrystalline nature with monoclinic monazite crystal system. SEM and TEM micrographs indicate the formation of ultrafine particles depicting spherical morphology with slight agglomeration and cluster formation. Fourier transform infrared spectroscopy (FTIR) signifies the presence of water vibration modes in a particular wave number along with phosphate group and a slight shift in wave numbers when yttrium is induced into lanthanum phosphate. Thermogravimetric analysis (TGA) reveals that the structural phase transition takes place above 800 °C. Raman spectra gives insight into the order–disorder in the system and shows relevant peaks for symmetric and anti-symmetric of PO4 3−, O–P–O bending mode, rare earth—oxygen vibrations. The fluorescence spectra of the grown compositions were investigated. The results show strong emission peaks at 270 nm excitation, whose intensity increases along with the increasing dopant concentration. Ultraviolet (UV) spectroscopy reveals that the absorption bands lie in the ultraviolet range and the bands are particularly sensitive to the incorporation of dopant ion, i.e., with effect of doping bands shift towards the lower wavelength side.