Role of Nb5+-Nd3+ co-dopant in morphotropic boundary of electrospun PZT nanoneedles: Study on dielectric and piezoelectric sensitivity

Abstract

This study focused on the effects of individual and simultaneous modification of electrospun PZT nanostructures with doping by Niobium (Nb5+) and Neodymium (Nd3+) cations. The SEM, EDS, XRD, XPS, STA, and TEM analyses were performed to identify the role of the donor-acceptor on the morphology, crystallography, and morphotropic boundary (MPB) of PZT nanostructures. The results indicated that the nanowhiskers of PZT were formed after post-calcination at 800 ℃ for 2 h. The morphology of the nanowhiskers was not changed drastically with individual doping by Nb and Nd while co-doping caused to morphology switch to the nanoneedles. The perovskite PZT phase; Pb(Zr0.58Ti0.42)O3 (Zr-rich, rhombohedral) phase was achieved with doping by Nb, while Pb(Zr0.52Ti0.48)O3 (Ti-rich, tetragonal) was determined with doping by Nd. With the de-convolution of the Zr 3d spectrum of XPS, it was exhibited that the nearest composition to MPB was attributed to Nb-Nd co-doped PZT. The polycrystalline fiber arranged by tetragonal-rhombohedral was observed. It was also found that the concentration of oxygen vacancy was reduced with doping by Nb, while increased with doping by Nd. The dielectric properties of un-doped and doped PZT were investigated. The dielectric constant of PZT was increased with individual doping by Nb and Nd, while due to the donor-acceptor couple, a synergistic effect was observed for co-doping by Nb-Nd where maximum dielectric was 16 times higher than the un-doped PZT. Also, with measuring the output voltage, the highest piezoelectric sensitivity was observed in the Nb-Nd co-doped PZT sample. Our findings highly suggest the electrospinning method for achieving the nanostructured PZT to be employed in a variety of applications needs a high dielectric constant.