Fast charge separation and photocurrent enhancement on black TiO2 nanotubes co-sensitized with Au nanoparticles and PbS quantum dots

Abstract

Reduced TiO2 nanomaterials (so-called black TiO2) attract intensive research interests due to their excellent capability for harvesting solar energy. To obtain a high conversion rate of solar energy to electrical energy, we loaded Au nanoparticles (NPs) and PbS quantum dots (QDs) on as-prepared TiO2 nanotubes (TNT) and black TiO2 nanotubes by magnetron sputter technique and subsequently dip coating for enhancing their photoelectric behaviors. It was discovered that the loadings of Au NPs and PbS QDs result in over 45% enhancement of photocurrent for the black TNT under visible light, and only ∼9.12% enhancement on the as-prepared TNT (without reduction process). The loadings of Au NPs and PbS QDs might act as separation centers rather than only light absorbers to accelerate electron-hole separation and transport. The black TiO2 nanotube composites could be considered as an excellent photoelectrode material applied in the field of solar energy conversion due to their high visible light harvesting and photoelectric response.