Researchs On SPR Sensor Based On Metal Nanostructures/Graphene Composites

In the project of remediation of polluted water environment,the detection of trace heavy metal ions in water has been an important research orientation and the national environment department has also invested a lot of energy and costs.In recent years,the rapid development of nano materials provides a new opportunity and challenge for accurate,real-time and traces detection heavy metals of water environment.The SPR sensor chip developing metal nano structure and composite materials the technology and method for the detection of trace heavy metal ions in water has been widespread concern.The traditional SPR sensor is mainly based on the gold film as a sensing chip.However,the traditional gold film for micro analysis caused by refraction at low concentration sensing surface,the rate of change of sensitivity is not high,the sensitivity of the SPR sensor for detection of trace heavy metal in water needs to be further improved.This paper introduces the basic characteristics of the surface plasmon resonance of metal nanoparticles(Surface plasmon resonance,SPR),the basic principle of SPR sensor based on the exploration of metal nanostructures prepared by novel sensor thin film chip,in order to improve the sensitivity and rate analysis of SPR sensor for example,silver nanocubes,gold nanoparticles,gold octahedron graphene composite films.In this paper,the preparation methods and applications of silver nanoparticles and gold nanoparticles eight SPR particles are introduced.The experimental platform of wavelength modulation SPR sensor was established,and the experimental method for detecting the concentration of mercury in the glucose and heavy metal was established.The main research contents include:(1)based on the Kretschmann model,using continuous spectrum source,optical transmission,optical lens,optical prism,spectrometer and other equipment designs and builds the experiment platform SPR sensor of wavelength detection.The platform has the advantages of simple optical path,convenient operation.We studied the SPR effect of metal nano film using the platform.(2)Analysis of the morphology and size of metal nanoparticles play the key role to improve the sensitivity in the SPR sensor.The tip of the metal nanoparticles(such as the triangle structure,the star structure,the octahedron structure and so on)has a stronger sensitivity to the refractive index change of the surrounding environment.The electron dense and high electron dynamism of the metal nanostructures tip can greatly improve the optical properties of metal nanoparticles and significantly enhance surface charge polarization and the local electric field intensity,thus the SPR effect of the sensor was enhanced,detection sensitivity of low concentration substances was improved.(3)the 100 nm gold octahedron was synthesized and the sensing film was prepared by the same method.The experiment of heavy metal mercury ion detection was designed and the trace detection of mercury ion(detection limit 30ug/L)was realized.The experimental results show that the gold octahedron greatly enhances the SPR signal of the sensor,and improves the sensitivity and the rate of analysis to the low concentration of mercury ions.(4)graphene has great specific surface area,excellent mechanical strength and flexibility,good conductivity,high transfer efficiency,strong adsorption ability,and the extremely rich surface groups,which make graphene as supporting material combining with noble metal nanomaterial.Graphene materials can avoid the rally of metal nano structure itself r,so it can maintain a large surface area and good physical and chemical properties with high adsorption of heavy metals in polluted water.At the same time,the metal nanoparticles present in the two-dimensional graphene can effectively prevent the polymerization of graphene itself,so that the graphene material can be stabilized,and form the 3D structure of the nanostructure-graphene compositing material.In this paper,monolayer graphene,fabrication of metal-graphene composite thin films,with gold nanoparticles solution and dispersed graphene mixed aqueous solution good,sol is formed by cross-linking with glutaraldehyde with spin coating machine spin coated thin film sensor on glass slides.The metal-graphene composite material applied to SPR detection sensor to improve the stability and sensitivity of SPR sensor.Then we study application value and potential of graphene and its compositing material in trace heavy metal detection.