CoSi Nanostructures Prepared by Laser Ablation as Plasmonic Absorbers for Photothermal Conversion

Metal silicides are suitable for semiconductor applications ranging from contact junctions to gate materials due to their inherent compatibility with silicon technology. It was deemed that they are not suitable for surface plasmon (SP) applications because they exhibit larger optical losses than other plasmonic materials. Here, metal silicide nanostructures were exploited for light heating to utilize their SP-enhanced absorption loss. The particles, mainly in the crystalline CoSi phase, were prepared by laser ablation in liquid for the first time despite the challenges arising from complex phase behavior and multiple stoichiometries of the metal silicide. The CoSi particles showed excellent photothermal conversion efficiency (30.5% in the infrared range) as plasmonic absorbers, which makes metal silicides promising in versatile applications such as plasmon-enhanced catalysis, heat assisted magnetic recording, and thermophotovoltaics.