Fig. 6: Diagram of energy levels.

a Curves of (F(R)hν)^1/2 vs. hν for TiO₂, Ag/Ag-doped TiO₂ substrate and 4MBA/Ag/Ag-doped TiO₂ hybrid system, respectively. b Schematic diagram illustrating the photo-induced CT between the Ag/Ag-doped TiO₂ substrate and 4MBA molecule under the excitation of 785-nm laser.