Laser-induced fabrication of highly branched Au@TiO2 nano-dendrites with excellent near-infrared absorption properties

Abstract

In this report, highly branched Au@TiO₂ nano-dendrites with a tailored surface topography have been conveniently fabricated via a novel and effective laser-induced strategy. The TiO₂ nanospheres fabricated by laser ablation of the Ti target in H₂O₂ solution are characterized by abundant oxygen vacancies (OVs) on the (110) surface. Then, the hydroxyl radical (OH⁻) groups will be easily formed on the OVs in terms of water dissociation by UV laser irradiation of the TiO₂ nano-spheres at the liquid interface. With the aid of OH⁻ groups, the formation of Au@TiO₂ nano-dendrites is based on the overgrowth of gold on the TiO₂ nano-spheres through the reduction of HAuCl₄. The absorption spectra of Au@TiO₂ nano-dendrites show that localized surface plasmon resonance (LSPR) peaks can be effectively modulated from the visible region (∼545 nm) to the near-infrared region (NIR ∼ 1090 nm). The as-prepared Au@TiO₂ nano-dendrites with excellent NIR absorption properties have a promising potential for developing important novel sensors and super photo-catalysts.