Charge state of metallic nanoparticles on a conductive surface

The work is devoted to the analysis of charge state of a disordered system of metallic nanoparticles positioned on a conductive substrate. A theoretical model has been developed that describes thermally activated electron tunnel transitions between the particles as well as between the particles and the substrate, the last ones being caused by the difference in particle and substrate work functions. The model accounts for the inter-particle charge interactions and for the interaction of the particle charges with the image charges in the substrate. By using Monte Carlo simulations charge distributions in the structures with different nanoparticle densities in a single-layer coating on a substrate were obtained as functions of the dielectric constant of the environment and work function of the particles and the substrate. As an example, results are presented for the structures with Ni and Pt nanoparticles on a carbon substrate, which are often used as catalysts of chemical processes.