Optical response and structural properties of Fe-doped Pb(Zr_(0.52)Ti_(0.48)) O_3 nanopowders

摘要

In this paper, the Pb(Zr_(0.52)Ti_(0.48))_(1-x)Fe_xO_3 (FePZT, ⅹ = 0.05) nanopowders were prepared by dry and wet sol-gel methods in the morphotropic phase boundary (MPB) region. The effect of Fe concentration on the structural, morphological, and optical properties of PZT nanopowders was investigated using X-ray diffraction (XRD), Field emission scanning electron microscopy (FESEM), Fourier-transform infrared (FTIR), and Ultraviolet-Visible (UV-Vis) analysis. XRD results showed that the nanopowders have a perovskite structure with the tetragonal phase. The lattice parameters and average crystallite size of samples decreased from 33 to 21 nm with increasing Fe incorporation due to the substitution of Fe atoms instead of Ti and Zr atoms. FESEM images showed that all average diameters of the nanopowders decreased with the Fe concentration. The optical properties of the pure and FePZT nanopowders such as longitudinal optical (LO) and transverse optical (TO) phonon frequencies, refractive index, extinction coefficient, and the real-imaginary parts of dielectric function were examined by the Kramers-Kronig model. As a result, the TO and refractive index of nanopowders are increased by substituting Ti and Zr with Fe atoms due to their different ionic radius. Also, while the crystallite size increases from 20.95 to 33.52 nm, the LO-TO splitting increases too. The optical band-gap values of the pure and FePZT nanopowders were estimated using UV-Vis spectroscopy and Kubelka-Munk model. The band-gap increased from 3.52 to 3.60 eV with a decrease in the crystal size of nanopowders.