Graphene and related materials: from "scotch tape" to advanced production methods.

Abstract

The main topic of this thesis is the synthesis and characterization of carbon-based nanomaterials. In particular, during the first year of my PhD, I focused my attention on the synthesis of graphene, a carbon-based nanomaterial arranged in a two-dimensional (2D) crystal structure. The main purpose of the study was to optimize the method of synthesis of graphene, using the Scotch-tape technique, to obtain greater amounts of graphene compared to samples consisting of several layers. Although this technique leads to high quality graphene sheets, it is not the suitable approach to obtain a gram-scale production of graphene for its employment in nanoelectronics. During the second year, my studies focused on the synthesis and characterization of graphene-based nanomaterials. In particular, I have dealt with graphene nanowalls (GNWs), which consist of few graphene layers vertically oriented on a suitable substrate. These materials have attracted the interest of many researchers due to their potential applications as cathode materials for field emission devices. The last year of my PhD, I studied the effects of ablation of a graphite target either with a nanosecond or a femtosecond laser, in liquids. It was found that the laser ablation of graphite can lead to the synthesis of large graphene domains employing the nanosecond laser, while the use of a femtosecond laser produces large amounts of porous graphene sheets, that are recovered at the water-air interface and the graphene quantum dots that are dispersed in the liquid.