Research On Surface Plasmon Resonance Hydrogen Sensor Based On Ag/TiO2 Composite Film

As a renewable and infinitely recyclable energy source,hydrogen has been widely used in petrochemical,electronics,medical,aviation and other fields.At the same time,hydrogen is a clean energy with no pollution,which has also attracted the attention of people.However,hydrogen is a highly permeable,flammable and explosive gas,and there are great safety hazards in the process of production,transmission and use.Therefore,accurate measurement of hydrogen content in air and specific environments has important academic value and application prospects.In response to the rapid development and urgent needs of hydrogen sensors in recent years,this paper combines surface plasmon resonance sensing technology and optical fiber transmission technology to develop two high-sensitivity optical fiber hydrogen sensors based on silver/titanium dioxide composite film.Based on the principle of surface plasmon resonance（SPR）,a Kretschmann structure of silver/titanium dioxide（Ag/Ti O₂）composite film hydrogen sensor was developed,and the surface plasmon resonance spectrum of gas in the near-infrared band was studied.characteristic.The four-layer structure model of Kretschmann prism coupling is calculated by simulation,and the relationship between the resonance spectrum intensity and the thickness of the silver film,the thickness of titanium dioxide and the prism material is obtained,and the thickness of the composite film of silver and titanium dioxide is optimized to obtain the maximum sensitivity.The Ag/Ti O₂ sensitive film is designed as a replaceable disposable chip,and the Ag/Ti O₂ film is plated by magnetron sputtering method to prepare a hydrogen sensitive element for the sensing test of hydrogen.Under the excitation of1550nm wide light source,SPR resonance occurs at the interface of Ag/Ti O₂composite film.The hydrogen is tested by the movement of the reflected light wave trough.Spectral wavelength detection experimental system using Kretschmann prism coupling structure.Fix the light source and incident angle,and measure the wavelength shift.Experimental results show that the prepared Ag/Ti O₂ composite film can tune the resonance wavelength to the near infrared band of 1550 nm,enhance the spectral sensitivity of the sensor,and the sensitivity under low concentration（concentration range:14.7%-25%）hydrogen can reach-8.305nm/%.And by replacing the gas-sensitive membrane,different gases can be detected to increase biocompatibility and gas sensing capabilities.Based on the principle of SPR,a U-shaped optical fiber structure of silver/titanium dioxide composite film hydrogen sensor was developed.The structure of U-shaped fiber surface plasmon resonance sensor is designed.Optimize the preparation process of U-shaped single-mode fiber.Magnetron sputtering method is used to plate Ag-Ti O₂ film to prepare a single-mode U-shaped optical fiber SPR sensor,which is used for the sensing test of hydrogen.Combining UG software and 3D printing technology to design and prepare a reaction gas chamber,the experimental results show that the prepared sensor has a good response to hydrogen.The optical fiber sensor designed in this paper uses the interaction of light field and gas-sensitive material for hydrogen sensing.It has many advantages such as simple preparation,high sensitivity,explosion-proof and anti-electromagnetic interference,and has great application value in the fields of electronics,medical,aviation,etc.