Characterization, spectroscopic investigation of defects by positron annihilation, and possible application of synthesized PbO nanoparticles*

Abstract

Nanocrystalline samples of highly pure lead oxide were prepared by the sol-gel route of synthesis. X-ray diffraction and transmission electron microscopic techniques confirmed the nanocrystallinity of the samples, and the average sizes of the crystallites were found within 20 nm to 35 nm. The nanocrystallites exhibited specific anomalous properties, among which a prominent one is the increased lattice parameters and unit cell volumes. The optical band gaps also increased when the nanocrystallites became smaller in size. The latter aspect is attributable to the onset of quantum confinement effects, as seen in a few other metal oxide nanoparticles. Positron annihilation was employed to study the vacancy type defects, which were abundant in the samples and played crucial roles in modulating their properties. The defect concentrations were significantly larger in the samples of smaller crystallite sizes. The results suggested the feasibility of tailoring the properties of lead oxide nanocrystallites for technological applications, such as using lead oxide nanoparticles in batteries for better performance in discharge rate and resistance. It also provided the physical insight into the structural build-up process when crystallites were formed with a finite number of atoms, whose distributions were governed by the site stabilization energy.

Annealing effects on the structural, positron annihilation parameters, and electrical properties of Fe2O3- PbO2-TeO2 glasses

“…These changes may result in the stabilization of certain species, resulting in a decrease in vacancy concentration I 2 that agrees with previous data from XRD i.e., increasing the degree of crystallinity with PbO 2 concentration. The present data agreed with the result of Ali et al [55], who found that by heating the samples, the mean and bulk lifetime decreased. Figure 7 also showed the mean positron lifetime τ m and the positron lifetime in bulk samples τ b for the heated samples with various concentrations of PbO 2 .…”

Enhancing the microstructural, optical, and tensile properties of the PVC‐PMMA blend film: The role of PbO nanoparticles incorporation

“…The chemically produced lead oxide nanoparticles by Arulmozhi et al 26 has a crystallite size of 40 nm. Ali et al 27 used the same tool (the sol–gel method) and found that the average crystallite size lies between 20 and 35 nm. Moreover, Figure 1b depicts the Sol–gel produced lead oxide nano powder's XRD pattern.…”

Defect analysis and microstructural characterization of zinc-substituted cadmium oxide nanocrystallites by positron annihilation and supplementary methods

“…In an earlier work on Cd-substituted ZnO nanocrystals by Ghosh et al [13], strain-induced inhomogeneity had been found to lead to phase segregation of CdO from Zn 1-x Cd x O beyond a certain concentration. The studies earlier reported on a number of wide bandgap semiconductors, such as ZnO, NiO, TiO 2 , MgO, PbO, SnO 2 etc, also had met with similar restrictions owing to phase segregation of individual oxides beyond x = 0.2-0.3 [14][15][16][17][18][19]. The work by Ghosh et al [13] had in fact reported on the effects of doping Cd in ZnO but upto a concentration of x = 0.09.…”