Specific Features of the Shape of Lead Sulfide PbS Nanoparticles According to X-ray Diffraction and Magnetic Susceptibility Data

摘要

The shape and dimensions of the crystals have attracted the attention of researchers for a long time when minerals were identified by their habit. In modern materials science, study and modeling of the shape (geometry) of nanocrystals remain important tasks [1], since the shape of nanoparticles can affect the electronic, optical, and magnetic properties of matter [2], determining the patterns of chemical, physical, and biological processes. In other words, the developed surface of nanoparticles has a significant impact on their properties, atomic structure, and geometry. In this paper, it has been shown for the narrow-gap semiconductor crystal of lead sulfide PbS that analysis of X-ray diffraction data and results of magnetic susceptibility measurements makes it possible to assess the increasing effect of the surface atoms on the distortion of bonds in the particle with a decrease in particle size to a few nanometers. Below a certain particle size, the energy changes caused by the surface become critical for the stability of the structure. The distortions are compensated by changing the shape of the particle, in particular, as shown below, by the formation of additional vertices.