Post-exchange Of Ligands In 2D Nanoparticles Arrays

Self-assembly 2D nanoparticles arrays have attracted widely attention due to their unique properties and potential application.The properties of this kind of materials largely depend on the distance between the nanoparticles in the 2D nanoparticles arrays,so adjusting the distances between the nanoparticles could expand the application prospect.For nanomaterials,the surface ligand plays a crucial role in the synthesis,assembly and properties.Exchanging the surface ligands of the nanoparticles or arrays is an effective strategy to adjust the array and improve the related properties.The dissertation has chosen several dithiones with different lengths to exchange the surface ligands of the prepared Au 2D nanoparticles arrays,and investigated the influence of the chain length of the exchanging ligands on the distance between the nanoparticles.Firstly,we have synthesized the relevant Au nanoparticles by the method reported in literatures and then fabricated closely packed self-assembly Au 2D nanoparticles arrays on the Teflon tape.In order to enhance the stability of the 2D nanoparticles arrays in the organic solvent,thermal annealing of the prepared Au nanoparticles arrays was carried out,and then the Au nanoparticles arrays were soaked into the different dithiones solution for the ligands replacement.In the Uv-visible spectroscopy,the maximum absorption wavelength ?max of the 2D nanoparticles arrays increased with the decrease of the chain lengths of the dithiones,while the TEM images directly reflected that the distance between nanoparticles reduced as the chain lengths of the dithiones decreased.Secondly,owing to the disadvantages of the 2D nanoparticles arrays on the Teflon substrate such as difficult characterization,we chose quartz plate as the assembly substrate to explore the influence of the ligands exchange.The Uv-visible spectroscopy,TEM and GISAXS results all showed that the Au 2D nanoparticles arrays had better length range order.Similarly to Teflon substrate,using the ligands exchange method with quartz plate as the substrate can effectively adjust the distance between nanoparticles after thermal annealing.After ligands exchange,the ?max of the Au 2D nanoparticles arrays on the quartz substrate appeared obvious red-shift.The TEM images indicated that the distance between nanoparticles decreased as the chain lengths of dithiones reduced.The GISAXS date also showed that the center-distance between nanoparticles decreased from 6.14 to 5.78 nm.