Towards visible light hydrogen generation: Quantum dot-sensitization via efficient light harvesting of hybrid-tio 2

Abstract

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 ∼16.2âmA/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 ∼14.2âmA/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.