PbS nanoparticles: Synthesis and size determination by X-ray diffraction

PbS particles down to 60 nm in size are prepared by chemical precipitation from aqueous solutions. An x-ray diffraction procedure is described for determining the particle size and atomic structure. The PbS particles precipitating in the solution bulk are shown to be monocrystalline. Reducing the particle size of PbS from 300 to 60 nm increases the rms atomic displacements (by 30%) and lattice strain (by 0.1%) in the particles. The lattice parameter of PbS is found for the first time to increase with decreasing particle size.