Experimental Study On Graphene Oxide Observation By Femtosecond Laser Induced Breakdown Spectroscopy

Femtosecond laser-induced breakdown spectroscopy(fs-LIBS)is favored by researchers because of its unique elemental analysis technology,and has been widely used in various fields.In recent years,graphene still face great challenges in the processing of large-scale surface structures,the control of properties and the fabrication of micro and nano devices.However,researchers have studied that graphene-like structures can be obtained by reducing graphene oxide to different degrees,which can effectively solve several problems in the application of graphene and expand the application of graphene and graphene oxide.In this paper,we focus on the signal enhancement methods and quantitative detection of the reduction degree of graphene oxide.Meanwhile,we observe the signal intensity of graphene oxide and explore the signal enhancement methods based on fs-LIBS technology.Also,we use fs-LIBS to observe the spectral intensity of carbon and oxygen in graphene oxide(solid and solution)during the reduction process.Moreover,we can accurately obtained the reduction degree of graphene oxide under different treatment conditions by analyzing the change of spectral intensity of corresponding elements.The main results and innovations of this paper are summarized as follows:(1)In the experiment of observing the corresponding spectral signal in graphene oxide based on fs-LIBS,we explain the inconspicuous enhancement effect relative to fs laser single pulse under the technical methods of different pulse delays of fs laser double pulse and coating with appropriate thickness gold nanofilms in the material surface based on its metalloid properties and its own hierarchical structure,which expand the potential research of graphene-like materials.(2)We propose a simple and convenient method to quantitatively detect the reduction degree of graphene oxide.Fs-LIBS is used to detect the spectral intensity of oxygen of GO in different reduction degree and then,the observed data are compared with the results of XPS and the fs-LIBS results correlate well the XPS results.Also,the fitting trends are independent of the fs laser incident fluences which can eliminate the detection limit of specific fs incident laser fluence,and finally we obtains the fitting expression between the two parameters.It expands the application of fs-LIBS in the quantitative detection of graphene-like materials.(3)We use different fs laser fluences to reduce the GO solution and then fabricate to thin films.The changes of spectral intensity of carbon and oxygen corresponding to GO films in different reduction degree are detected by fs-LIBS.Then we obtain the fitting curves between the signal intensity ratio of carbon and oxygen and the fs laser reduction energy and find that the fitting trends are also independent of the fs laser incident fluences,which can eliminate the detection limit of specific fs incident laser fluence.Finally,we achieve the qualitative detection of GO solution,and improve the application of fs-LIBS in the qualitative detection of graphene-like materials further.