First Principle Study of Surfaces and Interfaces

This thesis concerns the study of surface and interface properties by means of ab-initio calculations. Nanostructures have received a growing interest in the last decades and the continuous shrinking of dimensions enhances superficial and interfacial effects over the bulk ones. These phenomena are present in both organic and inorganic materials and their combinations. Such studies represent great challenges and joint efforts of experimental, theoretical and first principles studies are needed. I focused my attention in three particular systems: i) the study of graphene/alpha-quartz interface as example of inorganic-inorganic interface for applications in Si-compatible electronics; ii) the adsorption of a PDIF-CN2 molecular layer on Silicon substrate, for application in organic field effect transistor, as an example of organic-inorganic interface; iii) the study is the organic-organic interface between a PCBM molecular layer adsorbed on P3HT polymeric crystal which represents one of the best candidates for application organic photovoltaic cells. Part I of the thesis is devoted to present the main theoretical methods and numerical tools adopted. Part II is devoted to the presentation of the three topics quoted above. The appendices A e B report two further topics r addressed during my PhD period: Quantum transport in thermoelectric materials, and Raman spectra in anisotropically strained graphene.