Local Heating Control of Plasmonic Nanoparticles for Different Incident Lights and Nanoparticles

This paper investigates the nanoscale control of heating processes in the Au nanostructures from the aspects of light sources, nanoparticle morphologies, multi-layer Au shells, and nanoparticle dimers. The spatiotemporal evolution of the temperature profile inside and around the Au nanoparticles is computed using a numerical framework based on the finite element method. One-temperature model and two-temperature model are used for the calculation of continuous-wave and picosecond pulse laser, respectively. Results show that the maximum temperature increase is linear with the laser energy density, the slopes of which are various for continuous-wave laser and picosecond pulse laser. For the Au cube, ellipsoid, ring, and sphere with the same volume, the maximum resonance wavelengths locate in 580 nm, 610 nm, 500 nm, and 530 nm, respectively. The trend of the maximum temperature increase agrees well with the absorption cross section. With increasing the number of the shell, a red shift occurs from 665 to 690 nm and the total absorption cross section also increases. What needs to be emphasized is that it does not need to heat the surrounding environment while the core region remains a very high temperature, which is very interesting and suitable for photothermal applications such as photothermal catalysis and nanoreaction oven. For the nanoshell dimers, it can be heated selectively by adjusting the incident angle and light wavelength for this dimer system.