Synthesis, characterization of undoped and doped Zn_3(PO_4)_2ZnO nanopowders by sol-gel method

摘要

Nanopowders of undoped and V_2O_5-doped Zn_3(PO_4)_2ZnO are prepared at room temperature by sol-gel method. Structural, morphological and spectral properties of the prepared nanopowders are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy, transmission electron microscope (TEM), fourier transform infrared spectroscopy, UV-Vis. Spectroscopy, photoluminescence (PL) and electron paramagnetic resonance (EPR) techniques respectively. XRD analysis confirms that the prepared samples are in crystalline nature with monoclinic phase of Zn_3(PO_4)_2 and hexagonal wurtzite phase of ZnO. The lattice cell parameters, unit cell volume, dislocation density, strain and grain sizes are calculated. SEM and TEM images showed domain like structures. The functional groups corresponding to the PO_4 ~(3−) groups and Zn-O bands are observed in the IR spectra. From the optical spectra, the band gap energy of the prepared nanopowders decreases with increasing dopant concentration is observed. The PL spectra of all the samples exhibit four emission peaks in the visible region, in which strong emission peak (462 nm) in blue region indicates their higher structural and optical quality. From EPR spectra, vanadyl ion exists in an octahedral environment of oxygens with tetragonal distortion.