▎ 摘　　要

NOVELTY - Preparing graphene composite film on silicon wafer surface comprises soaking silicon wafer in aqua regia, rinsing and drying, soaking in a solution comprising e.g. sulfuric acid, drying, hydrolyzing the processed silicon wafer, soaking in phosphorus oxychloride solution, assembling large phosphate groups on the silicon wafer surface to obtain silicon wafer surface assembled with amino silane film, soaking in graphene oxide suspension, drying to obtain the silicon wafer surface deposited with modified graphene oxide composite film, and heating to obtain the reduced graphene composite film. USE - The method is useful for preparing graphene composite film on silicon wafer surface. ADVANTAGE - The method is economical with simple preparation, and produces graphene composite film, which improves the optical properties of solar cells and hence an ideal photoelectric conversion material. DETAILED DESCRIPTION - Preparing graphene composite film on silicon wafer surface comprises: (i) soaking silicon wafer in aqua regia, heating for 5-6 hours, naturally cooling at room temperature, removing, rinsing and drying, soaking in a solution comprising sulfuric acid and hydrogen peroxide in a volume ratio of 70:30, processing at room temperature for 1 hour, ultrasonically cleaning using deionized water, placing in a dust-proof device, drying in an oven, soaking the processed silicon wafer in ethanol solution with an amino silane concentration of 0.1-1.0 mmol/l, ultrasonically processing for 3 minutes, allowing to stand, hydrolyzing for 0.5-1 hour, cleaning using absolute ethanol and deionized water, drying under nitrogen, placing the obtained silicon wafer in the oven, insulating at 90 degrees C for 90 minutes, soaking in phosphorus oxychloride solution, reacting for 2 hours, cleaning using deionized water, drying in nitrogen, assembling large phosphate groups on the silicon wafer surface to obtain silicon wafer surface assembled with amino silane film; (ii) soaking the graphene oxide in a rare earth modifier at room temperature, soaking for 2-4 hours, filtering and drying, adding the graphene oxide into a dispersant (0.1-0.2 mg/ml), and ultrasonically dispersing for 1-3 hours at 120 watts to obtain a stable suspension; and (iii) soaking the silicon wafer surface assembled with amino silane film in the prepared graphene oxide suspension, allowing to stand at 20-80 degrees C for 0.5-10 hours, removing, cleaning using deionized water, rinsing, drying in nitrogen to obtain the silicon wafer surface deposited with modified graphene oxide composite film, placing the film in the oven, filling argon protection gas, and heating to 200 degrees C for 2-3 hours to obtain the reduced graphene composite film.