Towards particle size regulation of chemically deposited lead sulfide (PbS)

Powders and solid films of lead sulfides (PbS) were produced by chemical bath deposition from thiourea aqueous solutions at a temperature of 325 K. By a Rietveld-like analysis of the X-ray spectra, it was shown that nanocrystalline PbS has the same rock salt structure B1 (space group Fm-3m) as coarse grained or single crystalline PbS. Nevertheless, this B1 structure is a very distorted structure with root mean square displacements up to 0.011 nm and with a microstrain up to 0.3%. The particle sizes in the PbS powders and films measured by scanning electron microscopy (SEM) are found to be in agreement with those determined by Bragg-Brentano X-ray diffraction (XRD) on powders and by glancing incident diffraction (GID) on films. It was found that by changing the chemical affinity in the range from 31.4 to 38.7 kJ/mol, it is possible to regulate the particle size of the chemically deposited sulfide powders from 100 to 300 nm.