Synthesis and applications of high-quality 2D pnictogens: antimonene and bismuthene

Abstract

The scientific community's interest in two-dimensional (2D) materials has been increasing since the appearance of graphene. Among the great variety of these nanomaterials, the elements of group 15 have attracted increasing attention due to their outstanding physical and chemical properties and their potential technological applications ranging from electronics to medicine. However, obtaining these materials in large quantities with the necessary quality remains challenging. For this reason, in this PhD Thesis, different production methods of these materials have been explored, analyzing the synthetic parameters and the quality of the obtained materials exhaustively. The introduction of this work aims to give a state-of-the-art overview of the large variety of 2D materials that currently exist, focusing on the elements of group 15 of the periodic table, and more specifically on antimonene and bismuthene, which are the main objectives of this work. This section points out the exceptional properties that these materials present compared to their bulk counterparts. In addition, a vision of the different approaches that can be followed for the preparation of these materials is given, and several examples of their use in a broad range of applications. The first work presented in this book describes the optimization of the liquid phase exfoliation process to obtain few-layer antimonene nanosheets. A selection of the experimental parameters affecting the preparation process has been analyzed to obtain high-quality suspensions in high concentrations. In the second study, chemical synthesis is used for the production of highquality antimonene nanolayers. To this end, the reaction parameters working in a discontinuous process have been analyzed, and the morphological and structural characteristics of the obtained material. Likewise, the same process is presented in a continuous flow procedure, which is developed to increase the yield of the reaction. Finally, the mechanical and electrical properties of the synthesized antimonene nanosheets are analyzed. The third work describes a procedure to synthesize bismuthene nanosheets of hexagonal shape using a colloidal synthesis approach. This new method is carried out through a two-step process under moderate conditions. In this study, the analysis of the synthetic parameters and an in-depth characterization of the obtained material is carried out. Finally, two additional works have been carried out with the aim to show the potential of these 2D materials as biosensors. The first study shows the modification of gold electrodes with antimonene nanosheets and the fabrication of simple devices able to detect mutations in specific sequences of DNA. The second study describes the fabrication of NADH biosensors by modifying graphene electrodes with bismuthene nanosheets. These two works suggest the high potential of these novel 2D materials for selected applications