Photoelectric properties of SnO2 decorated by graphene quantum dots

Graphene quantum dots (GQDs) were synthesized by a hydrothermal cutting method, and SnO2/GQDs composites were prepared by a one-step solvothermal method with SnCl4 center dot 5H(2)O as a tin source. GQDs presented a size of 10 nm and a topographic height of 1 nm, indicating that GQDs are roughly 2-3 graphene layers. The interplanar spacing of 0.24 nm and 0.34 nm corresponded to the crystal plane of GQDs (1120) and (002), respectively. Owing to the electrostatic interaction, the incorporation of positive SnO2 with negative GQDs results in the zeta potential decreased from 7.08 mV to -2.22 mV. The photoelectric properties of SnO2/GQDs composites were investigated. When the ratio of GQDs reached 0.30 wt%, the photocurrent value of SnO2/GQDs composites achieved a maximum of 3.008 x 10(-4)A/cm(2) and the corresponding interface contact impedance reached a minimum.