New developments in X-Ray photoelectron spectroscopy applied to nanostructured materials

The study and characterization of nanostructured materials is growing very fast and potential applications of new materials at the nanoscale are envisaged, based on the general observation that the performance of matter at molecular scales will exhibit unexpected features, depending on size, shape and composition. The phenomena occurring at the nanoscale are of fundamental interest and involve synthesis and chemical-physical studies, optoelectronic and biotechnological characterization, for applications in several field of technology. One of the main goals to the study of nanostructured systems is to deeply understand the behavior of materials when the sizes are close to molecular dimensions. To address this purpose, different techniques have been developed and among surface sensitive techniques, X-ray Photoelectron Spectroscopy (XPS) is particularly suited and largely employed. In fact, XPS provides fundamental information on sample surface, elemental composition and chemical state of the elements of the material under analysis. By the analysis of the Binding Energy (BE) of core electrons, this technique allows qualitative elemental identification. Little BE variations, due to the chemical environment of the selected atom, determine the oxidation state and its perturbation due to the formation of new chemical bonds with interacting species. XPS surface sensitivity to the outmost layers of the investigated materials is an important peculiarity when the surface plays a fundamental role, as in nanostructured materials, in which the chemical nature of the surface, the surface reactions, the interface characteristics and molecular adhesion have a primary function. In this commentary the research developments and future perspectives of XPS characterization of nanostructured materials will be reviewed, with particular attention to surface and interface effects for nanoparticles of different sizes and shapes. Reports on these extremely important topics will be addressed. © 2011 Nova Science Publishers, Inc. All rights reserved.