On the optical properties of lead chalcogenide nanoparticles

Lead chalcogenide (PbS, PbSe) nanoparticles are prepared for two equimolar concentrations (0.25 and 0.5) by simple and low cost sol–gel method at room temperature. The obtained Pb(S,Se) nanoparticles were characterized by XRD, FTIR, SEM and Optical analysis. The XRD pattern confirm the Pb(S,Se) nanoparticles have face-centered cubic structure and crystallinity found to be increased as increase (0.5 mol L−1) the concentration. Average crystallite size is found be around 62–69 nm and 66–70 nm for PbS and PbSe, respectively. The FTIR spectra confirms the presence of stretching and bending vibrations of PbS at 615, 976, 1096 and 1366 cm−1 and SeOSe vibrations at 656, 736 and 852 cm−1. In the SEM images, coalescence between grains, homogeneous agglomeration form with spherical particles has shown which is found to be less than 0.5 μm. The band gap energy of PbS is found to be 1.6 eV and 2.1 eV for PbSe.