▎ 摘　　要

NOVELTY - Composite material comprises lead sulfide quantum dots, graphene and poly(3-ethylthiophene) in mass ratio of 1:0.25-4:10. USE - Composite material. ADVANTAGE - The composite material is easy to operate and prepared in a simple manner. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing composite material, which involves: (A) preparing graphite oxide by dissolving natural flake graphite type 434 in 98% of sulfuric acid (30-40ml) under ice-water bath; (B) mixing natural flake graphite with potassium permanganate in mass ratio of 1:5 for 0.5-2 hours; (C) transferring obtained mixture to water bath at 30-40 degrees C for 30-60 minutes; (D) mixing obtained product with deionized water (80-120ml) at 50-70 degrees C for 0.5-2 hours and then obtained product is mixed with 30% of hydrogen peroxide (10-20ml) for 1-20 minutes with continuous stirring; (E) centrifuging obtained product to obtain solid product; (F) washing obtained product with 2-10wt.% of hydrochloric acid; (G) drying obtained product at 5-80 degrees C for 24-48 hours in vacuum oven to obtain dry graphite oxide; (H) preparing graphene by sonicating graphite oxide is dispersed in deionized water (0.5-1mg/ml) for 2-5 hours; (I) mixing obtained solution with 85% of hydrazine hydrate solution (10ml/g) at 7-80 degrees C for 24-48 hours under reflux bath; (J) washing obtained product with deionized water (pH 7) and then lyophilizing obtained product; (K) grinding obtained product to obtain graphene powder; (L) preparing lead sulfide quantum dots by dissolving lead chloride in oleylamine (5-10ml) at 90-120 degrees C for 2-3 hours in presence of argon to obtain lead precursor; (M) dissolving sulfur in oleylamine (7.5-30ml) at 90-120 degrees C for 2-3 hours in presence of argon to obtain sulfur precursor; (N) mixing lead precursor and sulfur precursor in molar ratio of 0.2-10:1 at 9-120 degrees C for 2-10 minutes; (O) quenching obtained product in n-hexane and then keeping obtained product for 24 hours; (P) purifying obtained product with ethanol and redispersing obtained product to obtain lead sulfide quantum dots; (Q) sonicating graphene in toluene solution for 1 hour and then mixing obtained solution with lead sulfide quantum dots in oleylamine (0.5-2ml), where graphene and lead sulfide quantum dots are mixed in molar ratio of 1:0.25-4; (R) centrifuging obtained product to collect precipitate and then redispersing precipitate in toluene to obtain lead side quantum dots and graphene composite material; and (S) dissolving poly(3-ethylthiophene) in dichlorobenzene at 50 degrees C and then mixing obtained product with lead side quantum dots and graphene composite material in ratio of 10:(2-5) at 40 degrees C for 16 hours to obtain desired product.