Nanomaterials Based Fluorescent Sensors for Sensitive and Selective Nitro-explosives Detection

The Ph.D. project aims at developing novel fluorescent nanomaterials for fast, sensitive, selective, reliable and cost-effective detection of nitro-explosives. Early research focused on the pyrene-doped polymer systems. Firstly, pyrene-polystyrene fluorescent nanoporous films have been prepared through a simple dip-coating process, and used for explosives vapour detection with ultra-sensitivity and selectivity. Morphology investigations revealed that films consisted of a large-surface, three-dimensional nanopores and the possible molecular origin of fluorescence quenching was investigated through structural XRD studies and electronic structures. Later, super-hydrophobic fluorescent sand was prepared and applied for buried explosives detection. In order to detect nitro-explosives in aqueous phase, pyrene-polyethersulfone electrospun nanofibers were synthesized through electrospinning using mixed solvents. The current sensor demonstrated excellent sensitivity, selectivity and reusability to nitro-explosives detection and static quenching mechanism. An ultrafast and facile method for the preparation of fluorescent nitrogen-doped carbon nanoparticles (CNPs) has also been developed from a single precursor under microwave conditions. The obtained CNPs showed strong blue fluorescence, which could be quenched by picric acid sensitively and selectively. Furthermore, fluorescent carbon dots co-doped with nitrogen and phosphorus were prepared with high quantum yield and dual fluorescence emission, and applied as ratiometric sensors for explosives detection. Finally, a fully biodegradable and environmental-friendly protein showed sensitive, selective and rapid detection of picric acid, and its excellent sensing performance was attributed to the synergistic effect of electron transfer, energy transfer as well as acid-base interactions. This dissertation opens an avenue in the design and synthesis of fluorescent nanomaterials for wide applications beyond nitro-explosives detection