Size-, Shape-, and Dimensionality-Dependent Melting Temperatures of Nanocrystals

On the basis of a model for size-dependent cohesive, energy, the size, shape, and dimensionality effects on melting temperatures of nanocrystals are modeled in a unified form. The model predicts that the melting temperature T-m(D,d,lambda) decreases with reducing size D and dimensionality d or increasing shape factor lambda. For nanoparticles with the same D values, there is T-m(icosahedron) > T-m(sphere or cube) > T-m(octahedron) > T-m(tetrahedron). Moreover, the ratio of depression of T-m(D,d,lambda) is about 1:2 lambda(wire):3 lambda(particle) for thin films, nanowires, and nanoparticles when D is large enough, for example, 6 nm. The model is found to be in accordance with available experimental, MD simulation, and other theoretical results for An, Ag, Ni, Ar, Si, Pb, and In nanocrystals.