| Fluorescence effect refers to the phenomenon that the dye emits fluorescence with excitation of specific wavelengths of light.Fluorescence plays an irreplaceable role in the development of biological detection,labeling,and biochemical sensors due to its diverse colors and high sensitivity.In previous reports,there was no other way to enhance the fluorescence effect except for adding metal or oxide nanoparticles as the scattering medium.However,with the development and application of new carbon materials,graphene has attracted wide attention due to its special conductive property and energy band.It makes enhancing fluorescence effect possible through regulating and controlling from various angles by combining graphene with dyes.The experiment prepares Au nanoparticles(Au NPs)and investigates the effects of three kinds of scattering systems doped with Au nanoparticles,graphene and graphene/Au NPs in dye DCJTB on fluorescence emission,and it achieves fluorescence enhancement and quenching.The thesis mainly includes the following three parts:?.Au NPs is prepared by reduction methods and characterized by microscopes,spectrometers,scanning electron microscopes and other instruments.All of these processes analyze the influencing factors of Au NPs in the experiment.The Au NPs prepares scattered uniformly in the aqueous solution,which appears light red and its absorption peak is 564 nm.Au NPs,with a diameter of 50 nm,has a round spherical structure,which provides raw materials for exploring the influence of graphene and Au NPs on the fluorescence of dyes.?.Different film systems are constructed.The appropriate film layers were selected for the fluorescence effect experiment doped with dyes.The influence of waveguide structures of different films on the random laser emission was studied.PDMS has good quality in forming film,and different layers have different effects on fluorescence.The fluorescence intensity of the double-layer sample is higher than that of the single-layer sample due to uniform dye dispersion and smooth surface of the film layer.Therefore,PDMS double-layer film is preferred as the film layer to investigate the fluorescence effect of doping dyes.PMMA is easily soluble in methylene chloride solution,and thinner dye-doped films are obtained after spin-coating.The dye random laser is obtained in the PMMA film system,and the three-layer film sample has the strongest laser intensity.?.Construct three kinds of system,which doped with Au nanoparticles,graphene and graphene/Au NPs in dye DCJTB.It measures the effects of graphene at different concentrations on the fluorescence measurement and analyzed the mechanism in the 3 systems.The results show that Au nanoparticles can significantly enhance the fluorescence emission of DCJTB and keeps the ratio of DCJTB and Au nanoparticles in the system unchanged.But by changing the concentration of graphene,the change of dye fluorescence decreasing,increasing and decreasing is achieved.When the graphene concentration is relatively low,it shows strong scattering effect,which makes the fluorescence intensity of the system reach the maximum.When the concentration is further increased,the high concentration of graphene intensified the dye's self-absorption of fluorescence radiation,leading to the decrease of fluorescence intensity.In this study,graphene or Au nanoparticles are used to regulate the fluorescent effect of dyes.Different effects on dye fluorescence can be achieved by changing the concentration,which has important value and guiding significance for the study of surface enhanced fluorescence,random laser and signature code recognition. |
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