▎ 摘　　要

NOVELTY - Preparing a graphene film, comprises mixing crystalline flake graphite, sodium nitrate and concentrated sulfuric acid in ice bath and then mixing, adding potassium permanganate and then stirring and heating, adding heated mixture with water to stir, adding water and hydrogen peroxide and then stirring, adding the suspension with dilute nitric acid solution and then centrifuging, adding the centrifuge mixture with water and then mixing, condensing the graphene oxide solution in a drier and then drying, and adding the graphene oxide powder with ethanol and then ultrasonically dispersing. USE - The method is useful for preparing graphene film (claimed). ADVANTAGE - The method is capable of economically preparing the preparing graphene film with good conductivity, light intensity, less energy consumption and argon gas flow rate of 10-30 torr. DETAILED DESCRIPTION - Preparing a graphene film, comprises (a) weighing 6-10 g of crystalline flake graphite, 6-10 g of sodium nitrate and 350-400 ml of concentrated sulfuric acid in an ice bath and then mixing, slowly adding 45-55 g of potassium permanganate and then mixing, stirring and heating at temperature of 35 degrees C for 2 hours, adding heated mixture with 320 ml of deionized water and then stirring for 15 minutes, adding 800 ml deionized water and 40 ml of hydrogen peroxide and then stirring for 10 minutes to obtain a green suspension, (b) adding the suspension with 0.0001 mole/l of dilute nitric acid solution and then centrifuging at speed of 1000 revolutions per minute (rpm), adding the centrifuge mixture with deionized water and then mixing to obtain a graphene oxide solution, (c) condensing the graphene oxide solution in a drier and then drying to obtain graphite oxide powder, (d) adding the graphene oxide powder with 80-90 mass% of ethanol with a concentration of 1 mg/ml and then ultrasonically dispersing for 25-35 minutes to obtain a solution and then coating on the graphene oxide film having a thickness of 200-300 nm, and (e) placing the quartz in an illumination reduction device for 5-60 minutes, and performing reduction-oxidation process of the graphene film to remove oxygen-containing functional groups.