Size-Dependent Strain of Sn/SnO_<i>x</i> Core/Shell Nanoparticles

The lattice constants of metallic nanoparticles shrink with respect to that of a bulk material. This behavior affects the properties of nanoscaled crystallites and can influence their application potential. In this work, we investigate the size-dependent lattice parameters of core/shell Sn/SnO_<i>x</i> nanoparticles, synthesized via a simple chemical reduction method. Therein, the use of appropriate surface ligands, reaction temperature, and reaction time allows us to tune the mean particle size from 6 to 104 nm. X-ray powder diffraction revealed that the ß-Sn reflections shift toward higher angles for smaller particles, showing a size-dependence of the lattice constants. The change in the lattice constants varies, depending on the direction, and can be described as an inverse function of the diameter of the crystallites. The different degree of deformation can be explained by the direction dependency of the bulk modulus <i>K</i> and the interface energy γ of the monocrystalline tin nanoparticles