Preparation Of MX₂?M=Mo,W;X=S,Se?2D Nano Materials And Study On Their Electrical Bistable Characteristic

Recently,two nanomaterials were paid more attention due to their excellent physical and chemical performances,which they were applied in lubricant,solar cell,luminescent devices,electrically bistable devices,etc.In this paper,we focus on the contrallable synthesis of MoS₂,MoSe₂ and WS₂ nanomaterials and their application in electrically bistable device were inestigated systematically.The following contents are carried out:Firstly,MoS₂ Nano-sheets were synthesised by one pot method using 1-DDT as sulfur source and surfactant.The structure,component and property analysis of the samples were characterised by X-ray diffraction,XPS,TEM,Absorption,FTIR and Raman spectra.MoS₂nanoparticles were prepared by changing reaction conditions such as time,temperature and molybdenum sulfur ratio.The effects of these three reaction conditions on the morphology and structure of MoS₂ were investigated by XRD,transmission electron microscopy?TEM?and Raman spectroscopy.The formation mechanism of MoS₂ was preliminarily explored.On this basis,a series of sandwich structure EBDs with 1-ODT-MoS₂ Nano-sheets and PVA compound as activator were prepared,which indicated that this type of EBDs had better bistable performance.The results show that MoS₂ nanomaterials are very important for the electrical bistability of the devices.Furthermore,the charge transfer mechanism of electromechanical bistable devices is analyzed.It is considered that the main reason for the bistability of the device is the electric field induced charge transfer between MoS₂ nanomaterials and inert polymers under the action of electric field.Secondly,MoSe₂ Nano-sheets were synthesised by one pot method using Selenium as selenium source.It was proved that as-MoSe₂ belonged to hexagonal system by measuring X-ray diffraction and Raman spectrum.The morphology of as-MoSe₂ semiconductor nanocrystal was analyzed by transmission electron microscope?TEM?.The structure shows that the prepared product is multilayer lamellar structure.Then the MoSe₂ Nano-material with excellent properties is mixed with polymer PVA as the active layer material to prepare the electrical bistable device and the I-V characteristic curve is measured.The fabricated devices exhibit good electrical bistability and can perform stable"read-write-Erasure"operation shows from I-V characteristic curve that the maximum current switch of the device can reach 10⁴.Finally,the effects of these factors on the electrical properties of bistable devices were investigated by changing the thickness of functional layer and the polymer of functional layer.Finally,WS₂ Nano-sheets were synthesised by one pot method using 1-DDT as sulfur source and surfactant.It was proved that as-WS₂ belonged to hexagonal system by measuring X-ray diffraction?XRD?and Raman spectrum.The morphology of as-WS₂ semiconductor nanocrystal was analyzed by transmission electron microscope?TEM?.The results show that the prepared products are ultrathin and flake structure.A series of sandwich structure EBDs with 1-ODT-WS₂ Nano-sheets and PVA compound as activator were prepared,which indicated that this type of EBDs had better bistable peroformance.The fabricated devices exhibit good electrical bistability and can be read steadily.From the I-V characteristic curve,the maximum current-switching ratio of the device can reach 10³.Finally,the influence of these factors on the properties of the bistable device is investigated by changing the thickness of the functional layer and the polymer in the functional layer.