Porosity of Nanostructured Carbon Thin Films

The multiscale (from nano to macro) characterization of porous materials, in particular of thin films integrated in sensors, as in electrochemical, catalytic and biomedical devices, asks for non-invasive methods. Since the mechanical and morphological properties of the substrate may affect the resulting structural organization and the network of the porous film structure, the porosity of the thin film has to be characterized in situ, without removing it from the integrating substrate, by recognizing the different contributions. This chapter deals with standard methods used to characterize porosity, the theoretical framework used to describe the evolution of porosity with film thickness, the development of combined approaches which provide the possibility to describe many features of pores in thin films on different length scales. As a case study we present an in-depth analysis of the porosity and structure of carbon cluster-assembled thin films used as electrodes in energy devices.