Based On Transitional Metal Dichalcogenides Of The Preparation And Performance Of The Optical Fiber Evanescent Wave Sensor

In recent years,transition metal dichalcogenides?transitional metal dichalcogenides,TMDCs?have been concerned by more and more popular as the new energy materials.Tungsten disulfide?WS₂?as a representative of transition metal dichalcogenides has similar layered structure and it belongs to the hexagonal system,combined by the van der Waals force between layer and layer,layer grows by forming strong covalent bonds between W and S.The special anisotropic layered structure and higher specific surface area make tungsten disulfide have a huge application in photoelectric material and nano sensors.WS₂ are easier to absorb the biological molecules compared to the traditional of the two-dimensional material such as graphene,which greatly improving its application in sensors.More importantly,tungsten disulfide has high optical transmittance,stable chemical performance and it can be obtained at lower temperature.This paper based on transition metal dichalcogenides has the excellent properties in the evanescent wave sensor and evanescent wave sensors have extensive applications.We designed the in-situ growth of gold nanoparticles/tungsten disulfide of U-bent optical fiber evanescent wave sensor and the silver nanoparticles/molybdenum disulfide of D-bent optical fiber sensor.?1?We have been prepared in-situ growth of gold nanoparticles/tungsten disulfide U-bent optical fiber evanescent wave sensor,the U-bent type structure is more stable compared with the straight type structure and cone type optical fiber sensor,the U-bent type can markedly improve the sensitivity more importantly.The fiber core radius of 31.25?m,cladding radius of 62.5?m of polyethylene coated the multi-mode quartz fibers were chosen to make U-bent optical fiber evanescent wave sensor.The tungsten disulfide were growth on the fiber directly by sulfur precursor four generation of thermal decomposition of ammonium.In-situ grow out the uniform gold nanoparticles through the reduction reaction of WS₂.The composition of in-situ growth of gold nanoparticles can be applied to optical fiber evanescent wave sensor properly,which was proved by our experiment.We chose WS₂/U-bent optical fiber evanescent wave sensor,in-situ growth of gold nanoparticles/tungsten disulfide U-bent optical fiber evanescent wave sensor?which reaction time between WS₂ and HAuCl₄ is 45s as EWA-1 sensor?,in-situ growth of gold nanoparticles/tungsten disulfide U-bent optical fiber evanescent wave sensor?which reaction time between WS₂ and HAuCl₄ is 60s as EWA-2sensor?,respectively,to measure the ethanol solution which volume concentration is 10%to80%absorption rate,and the sensitivity??A/?C?of the sensor can get 0.65.The detection of the sensors range are bigger.The sensors have a quick response and a short recovery time.We also measured the sodium chloride solution.There is a potential practical value in monitoring of the concentration of salt in the solution?2?We have prepared the silver nanoparticles/molybdenum disulfide D-bent optical fiber sensor.D-bent optical fiber has the large evanescent field.Firstly we made D-bent optical fiber with chemical etching method by using the multi-mode optical fiber which radius of the fiber core is 31.25?m.Molybdenum disulphide can be growth directly on the optical fiber by thermal decomposition.We prepared the uniform silver nanoparticles by sol gel method.The D-bent fibers which growth molybdenum disulfide were dipped in silver solution in order to make the rules of the silver particles on the fiber surface.Using the silver particles/D-bent molybdenum disulfide optical fiber sensor detected the concentration of 20%to 80%of ethanol solution.People used the traditional sensors to measure the temperature.The sensors can well reflect little temperature change.We also used the silver particles/D-bent molybdenum disulfide optical fiber as the optical fiber evanescent wave sensor to measure the change of the temperature.In addition,we also used this optical fiber sensor as SERS sensor,and the results indicated that the special shape and material enhanced the Raman signal significantly.