Orientation of Core-Shell Nanoparticles in an Electric Field

Coated nanoparticles, which have a core-shell structure, have many applications. The attached manuscript shows some of our progresses in investigating the induced torque and orientation of such nanoparticles in an electric field. We show that the shell of a nanoparticle has an important effect on its orientation, even when the shell is thin and takes only a small portion of the total volume. For instance, a thin layer coating of highly conductive Au can dramatically change the induced torque on a SiO2 or TiO2 nanoparticle. For lossy dielectric particles, the permittivity, conductivity, field frequency and core-shell structure together determine the magnitude and direction of the induced torque, suggesting a significant degree of experimental control over nanoparticle rotation and alignment.