Graphene and rare earth up-conversion fluorescent composite material and preparation method thereof

The invention provides a graphene and rare earth up-conversion fluorescent composite material and a preparation method thereof. The method comprises the steps of: using a graphite powder as a raw material to prepare graphite oxide by a Hummer method; conducting ultrasonic dispersion on 5-85mg of graphite oxide into 24-60mL of water; then adding Y (NO3), Yb (NO3) and Er (NO3) in a total molar weight of 0.05-1mmol by a stoichiometric ration of 78:20:2 into the graphite oxide dispersion; adding 0.02-0.5g of NaF and stirring for 5-10min; transferring the mixture to a 100mL reactor; reacting for 4-24h at 200-240 DEG C; naturally cooling to room temperature; centrifuging for separation and washing the reaction product with deionized water twice to obtain a graphene and yttrium fluoride up-conversion fluorescent powder composite material, which comprises a mixture of two or three selected from the followings: graphene-YF3:Yb, Er; graphene-(alpha) NaYF4:Yb, Er; and graphene-(beta) NaYF4:Yb, Er. The method provided by the invention is simple, employs non-toxic raw materials, and can change type of the earth up-conversion fluorescent material and up-conversion fluorescence properties of a final composite material by simply adjusting conditions of a hydrothermal reaction.