Visualized Gas-sensing Response And Mechanism Study Of Nanoparticle-sensitized Graphene Oxide Thin Films

With the deepening of NH₃ sensing research,the requirements for sensing materi-als are also getting higher and higher.Structural color materials without external power supply,strong photobleaching resistance and stable structure have become new mate-rials in the field of gas sensing.In the thesis,the film interference between graphene oxide（GO）sheets was selected as the basis of structural color gas response,and the saturation and brightness of the film were regulated by nanoparticles with fluorescent properties.A multi–Color GO composite film with controllable thickness and no Angle dependence was prepared.The colorimetric sensing of NH₃ and amine gas TEA by GO composite films with structural colors was successfully realized.Firstly,the hazards of NH₃ and the research of gas sensing materials in recent years are summarized,and the development status of graphene-based materials in gas is integrated.Combined with optical sensing,the advantages of structural color in gas sensing in colorimetric sensing are introduced,and nanomaterials are used to make up for the deficiency of structural color changing with the change of Angle.The research content of this thesis is based on the structural color characteristics of GO.Then,based on the theory that fluorescent nanomaterials can improve the Angle dependence of structural color,carbon quantum dots（CDs）with different fluorescence were synthe-sized,different film preparation methods were explored,and the composite film of graphene oxide/carbon quantum dots with uniform color and stable structure was pre-pared.The sensing response of NH₃ and amine gas was predicted according to the functional groups of carbon quantum dots.The spectral shift and gas response reversi-bility of the composite film with structural color to gas response were verified by UV spectrum,and the feasibility of the composite film to gas response was verified by the resistance change of the electrochemical instrument.Finally,we tried to use metal nanoclusters with fluorescent properties to improve the Angle dependence problem of the structural color of GO films again.Copper nanoclusters with different fluorescence were synthesized by top-down method to pre-pare graphene oxide/copper nanocluster composite films,and the optical shift of gas sensing was explored to preliminarily verify the feasibility of graphene oxide/copper nanocluster composite films.The irreversibility of the GO/copper nanocluster compo-site film in the gas response was explored using electrochemical instruments.In summary,this thesis summarizes the experimental process and discusses and studies the experimental results.The innovation point of this thesis is to use fluorescent nanomaterials to reduce the angle-dependent structural color graphene oxide composite film and explore its visual detection of ammonia and amine gases,which is of great significance for the study of energy–Saving and environmentally friendly optical gas sensing.