Dipole-dipole interaction model for oriented attachment of BaTiO nanocrystals: A route to mesocrystal formation

Although mechanisms of mesocrystal formation have been studied by several research groups, they are still under debate; Why do nanocrystals aggregate with their crystal axes aligned? In the present Article, the electric dipole-dipole interaction model has been studied for collisions between two particles by numerical simulations to study the mechanism of oriented attachment of BaTiO nanocrystals under the experimental condition of their ultrasound-assisted synthesis. If 5 nm BaTiO nanocrystals have some spontaneous polarization, then only small particles aggregate with other particles and their crystal axes are aligned by the dipole-dipole interaction, which is consistent with the experimental results. It suggests that 5 nm BaTiO nanocrystals may have some spontaneous polarization, although it has been reported that below 10 nm the crystal structure of BaTiO is cubic. © 2011 American Chemical Society.