Synthesis and characterization of single crystal PbO nanoparticles in a gelatin medium

Single-crystal, lead-oxide nanoparticles (PbO-NPs) were synthesized via the sol-gel method in a gelatin medium. Long-chain gelatin compounds were utilized to terminate the growth of the PbO-NPs and to stabilize them. The gel that was obtained was calcined at 500, 550, and 600 °C for 1 h. The synthesized PbO-NPs were characterized using an X-ray diffraction (XRD) analysis, a thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and high-magnification and high-resolution transmission electron microscopy (TEM and HRTEM). The XRD patterns indicated a phase transformation from tetragonal to orthorhombic as the calcination temperature increased. The SEM and TEM images showed that the nanoparticles started to form at a temperature range of 550-600 °C. In addition, the TEM results showed that the average particle size of the nanoparticles was ~45 nm. The HRTEM images revealed single-crystal PbO-NPs with an orthorhombic phase. The optical properties of the PbO-NPs were studied using a UV-visible (UV-vis) spectrophotometer. The UV-vis absorption spectra of the PbO-NPs indicated absorption peaks in the visible region, which were attributed to the band gap of the PbO-NPs with an orthorhombic phase.