Metal-filled Carbon Nanotubes as a Novel Class of Photothermal Nanomaterials

Using micro-Raman spectroscopy, we have shown that by illuminating with a laser light at 632 nm an individual cobalt cluster-filled multi-walled carbon nanotube we can significantly increase the temperature of the tube at the metal-cluster site. This temperature enhancement induces a thermal gradient along the tube, whose lower limit is estimated of the order of 100 K/μm. The cobalt cluster acts as a heat radiator for the tube and this effect can be exploited for several cutting edge applications of these hybrid structures as innovative nanoscale photothermal systems, namely (I) light-activated, thermal gradient-driven devices or actuators, and (II) novel building blocks for heat assisted magnetic recording.