Enhanced near-infrared absorption and photo-thermal generation in black iron doped indium tin oxide

Band engineering of transparent semiconductors, such as TiO₂, SnO₂, has recently been attempted to become black colour in order to increase photocatalytic efficiency in the visible and near infrared ranges. Here, we investigated a previously-neglected property in black oxides by using the example of iron doped indium tin oxide nanoparticles: The photothermal effect in the visible and near-infrared ranges. We found a significant enhancement of the photo-thermal generation in the nearinfrared biological window that is due to photon absorption, with no significant contribution from surface plasmon resonance. This allows independent magnetic functionalization of the particles by iron doping. These particles may be used for in-vivo cancer treatment where heat is photo-termally generated, while keeping the magnetism as a mean for remote manipulation through permanent magnets.