Preparation And Study On Photoelectric Properties Of Coal-Based Carbon Films

Carbon is one of the most versatile elements of the organism and the most versatile element in the world.Carbon materials have various properties due to the anisotropy of sp2 hybridization of their internal carbon and the anisotropy of their arrangement,and exhibit certain potential iin optics,electricity,and energy storage.Compared with graphene,carbon nanotubes,graphene and other carbon materials,coal as a carbonaceous material has the advantages of abundant reserves and low price.And the preparation of carbon materials from coal as raw materials has broad research prospects.In this paper,the lignite is used as the carbon source.According to the unique chemical structure and composition of the lignite and existence of aromatic and aliphatic structure,a low-cost compatibility method was studied and Raman spectroscopy and X-ray photoelectron spectroscopy was used to analyze the influence of this method.And the supernatant after centrifugation is prepared into a coal-based carbon film by a simple film preparation method-spin coating method,and they are annealed at different temperatures,then their electrical properties are tested.Besides the effect of annealing on its internal structure is characterized.The results of this study indicate that the content of carbon,nitrogen and sulfur in the precipitate after ball milling of raw coal and isopropanol is basically unchanged,the content of hydrogen and oxygen and the volatile matter of water decrease,and the ash and fixed carbon increase;the mixed ball milling causes the raw coal to be broken,and the particle size is gradually reduced,which promotes the transfer of the hydroxyl group in the coal and the small particle size substance to the isopropanol solution;comparing the results of the Raman spectrum and X-ray photoelectron spectroscopy of raw coal,sediment and supernatant,it is found that the mixing ball milling process does not change the disorder of the raw coal and the bonding mode of the internal carbon atoms,the disorder and the internal carbon atom bonding mode of the supernatant after wet ball milling-centrifugation are consistent with the raw coal;annealing causes cracks and sintering on the surface of the coal-based carbon film,and as the annealing temperature increases,it becomes more and more obvious;annealing results in the increase of the disorder and the content of sp2 carbon atom of coal-based carbon film,and it shows an increasing trnd with the increase of annealing temperature;the unannealed coal-based carbon film does not exhibit sufficient conductivity,but it exhibits a certain electrical conductivity after annealing,and the electrical conductivity shows an increasing trend with the increase of the annealing temperature;the difference in electrical conductivity between the annealing temperature of 400? and 800? is 7 orders of magnitude,and the electrical conductivity of the films annealed at 700? and 800? are on the order of magnitude.