▎ 摘　　要

NOVELTY - A tungsten(IV) sulfide/graphene heterojunction film saturable absorber preparing method involves preparing tungsten(IV) sulfide thin film. The tungsten(IV) sulfide thin film is placed in a tubular furnace. Graphene grown on a copper substrate is cut to suitable size and shape, coated with poly(methyl methacrylate)/anisole solution, dried, washed and transferred to the surface of the tungsten(IV) sulfide thin film, followed by spin-coating poly(methyl methacrylate)/anisole solution on the surface of heterojunction film, heated, followed by rinsing with deionized water and cutting into 2x 2 mm. USE - Method for preparing tungsten(IV) sulfide/graphene heterojunction film saturable absorber. DETAILED DESCRIPTION - A tungsten(IV) sulfide/graphene heterojunction film saturable absorber preparing method involves preparing tungsten(IV) sulfide thin film by using magnetron sputtering method, taking tungsten(IV) sulfide polycrystalline block as target, providing a under a radio frequency power of 60 W and argon gas pressure of 50 Pa and heating quartz substrate at 200 degrees C, depositing for 1-20 minutes. The tungsten(IV) sulfide thin film is placed in a tubular furnace for heat treatment at a flow rate of 100 sccm through argon as shield gas, provided with low temperature of 200 degrees C and high purity sulfur powder, maintained at 550-850 degrees C for 1-10 hours and naturally cooled to room temperature. Graphene grown on a copper substrate is cut to a suitable size and shape, coated with a layer of 5% poly(methyl methacrylate)/anisole solution at a rotational speed of 1000-3000 rpm, dried at 80 degrees C for 10-60 seconds, immersed in a supersaturated solution of ammonium persulfate, subjected to etching off the copper substrate and floating the graphene-forming graphene film on the surface of the solution, washed with pure deionized water for 3-10 times, and transferred to the surface of the tungsten(IV) sulfide thin film to obtain a tungsten(IV) sulfide/graphene heterojunction thin film, followed by spin-coating poly(methyl methacrylate)/anisole solution on the surface of the tungsten(IV) sulfide/graphene heterojunction film at a speed of 1000-3000 rpm, immersed in a strong alkaline solution, heated to remove from the quartz substrate, followed by floating in the alkali solution surface, rinsing with deionized water for 3 times and cutting into 2x 2 mm.