Study Of The Synthesis And Physical Properties Of Titanium Disulfide Under High Pressure

Transition metal chalcodes（TMDs）are typical layered materials,which exhibit excellent optoelectronic properties under room temperature and pressure.TMDs can effectively overcome the defect of zero electron band gap in graphene,which has attracted widespread attention in the optoelectronic devices.TMDs possess different stacking modes because of the weak interlayer interaction,and the difference of crystal structure promotes the electronic behavior of TMDs,which leads to transformation from semiconductor to conductor or even superconductor.Its high thermoelectric conversion efficiency,high gas selectivity,strong absorption in the near infrared region,high electron mobility,high reversible specific capacity and good cycling performance,so it can be widely used in thermoelectric devices,gas sensors,photothermal devices and solar cells,etc.In this paper,we study the bulk TiS₂ as the main research object and prepare the bulk TIS₂ by chemical vapor phase transport method,and the lattice structure of bulk TiS₂ was learned by Raman spectroscopy and Diamond anvil Cell under high pressure.The main results are as followed.Firstly,the synthesis conditions of the bulk TiS₂were discussed by means of Chemical vapor transmission（CVT）method under different reactant ratios,different sealing,different temperatures and different reaction times.Finally,we obtain the best reaction conditions of the bulk TiS₂.Shortly,the ratio of reactants is controlled at the molar ratio of Ti to S 1:2,the quartz tube is sealed with a spray,the reaction temperature is 600℃and the reaction time is 48h.Secondly,the high pressure Raman spectroscopy of the bulk TiS₂ showed that four new Raman mode appeared in 53GPa.The three new peaks of N₁,N₂ and N₃ appeared at 17-18GPa,and the new peak of N₄ appeared at 34.56GPa,indicating that the lattice structure of bulk TiS₂ changed.