Figure 7.

Schematic representation of photo-generated electron transfer processes in a layered reduced graphene oxide/quantum dot (QD) structure with TiO_x interlayer (a) and the Energy Band Diagram (b) showing the main electronic processes at the interface in QDs: (1) Electron injection; (2) electron transfer; (3) Trapping of the electron at surface states; the two charge recombination pathways of trapped electron recombination with; (4) the hole at the valence band of QDs and; (5) the oxidized redox couple; (6) hole extraction. The recombination between the electron at Fermi level of rGO and the hole at the valence band of QDs and the oxidized redox couple was inhibited by TiO_x layer. Reprinted with copyright permission from reference [111]. Copyright © 2011, American Chemical Society.