  Photoinduced hyperthermia is a cancer therapy technique that induces death to
cancerous cells via heat generated by plasmonic nanoparticles. While previous
studies have shown that some nanoparticles can be effective at killing cancer
cells under certain conditions, there is still a necessity (or the need) to
improve its heating efficiency. In this work, we perform a detailed
thermoplasmonic study comparing the most effective nanoparticle geometries up
to now with a doughnut-shaped nanoparticle, demonstrating that the latter
exhibits a superior tunable photothermal response in practical illumination
conditions, i.e., unpolarized light. Furthermore, we show that nanoparticle
heating in fluidic environments, i.e., nanoparticles undergoing Brownian
rotations, strongly depends on the particle orientation with respect to the
illumination source. We conclude that the heating performance of nanodoughnuts
is outstanding, with a temperature increment 35% higher than the second best
nanoheater (nanodisks). Furthermore, nanodoughnuts feature a weak dependence on
orientation, being therefore, ideal candidates for photothermal therapy
applications. Finally, we present a designing guide, covering a wide range of
toroid designs, which can help on its experimental implementation.
