Thermo-electric-induced dichroism in ion-exchanged glasses: a candidate mechanism for the alignment of silver nanoparticles

In the present work, the alignment mechanism of silver nanoparticles on the surface of a heated ion-exchanged glass, in presence of an external uniform DC electric field parallel to the surface of the sample, is studied. At high temperature, the ionic silver clusters reduce to neutral ones and move toward the surface. Simultaneously, due to the external electric field the clusters interact with other ones as induced electrical dipoles. This leads to alignment of nanoparticles along and formation of a chain-like conductive structure, which makes the sample dichroic. Taking into account the matrix surface viscosity and using the method of image dipoles to model the influence of the substrate on the dipole interactions, we give an interpretation about the relative equilibrium positions of generated nanoclusters and consequently the formation mechanism of the chain-like structure on the surface of the ion-exchanged glass.