Towards Visible Light Hydrogen Generation: Quantum Dot-Sensitization via Efficient Light Harvesting of Hybrid-TiO(2)

We report pronounced enhancement of photoelectrochemical hydrogen generation of a quantum dot-sensitized hybrid-TiO(2) (QD/H-TiO(2)) electrode that is composed of a mesoporous TiO(2) layer sandwiched by a double sided energy harvesting layer consisting of a surface-textured TiO(2) inverse opals layer on the bottom and a patterned mesoporous TiO(2) layer on the top. CdSe/H-TiO(2) exhibits a maximum photocurrent density of ~16.2 mA/cm(2), which is 35% higher than that of the optimized control sample (CdSe/P25), achieved by matching of the bandgap of quantum dot-sensitization with the wavelength where light harvesting of H-TiO(2) is observed. Furthermore, CdSe/H-TiO(2) under filtered exposure conditions recorded current density of ~14.2 mA/cm(2), the greatest value in the visible range. The excellent performance of the quantum dot-sensitized H-TiO(2) suggests that alteration of the photoelectrodes to suitable nanostructures with excellent light absorption may offer optimal strategies for attaining maximum efficiency in a variety of photoconversion systems.