Investigated numerically nanoshell thickness on photothermal response of hybrid nanostructures in an aqueous medium

The current study describes the effect of changing a shell thickness on photothermal response of a hybrid nanostructures, using theoretical investigation based on the Finite Element Method (FEM) of the COMSOL multi-physics program. The hybrid nanostructures are the Core/Shell nanoparticles (C/S NPs) and the Core/Multi-Shell nanoparticles (C/MS NPs), with fixed core diameter (30 nm) and variable shell thickness (10–20 nm) to create a new type of hybrid nanostructures usable in photonic and optoelectronic applications. For these hybrid nanostructures, gold (Au) and silver (Ag) as a partner of titanium dioxide (TiO₂) were used in thermo-plasmonic part. Hybrid multi-shell nanostructures consist of silver-gold and gold-silver sandwich with titanium dioxide shell in between, all of which are dispersed in an aqueous medium (n = 1.33). The optical properties, the local field distribution, and local heating control of plasmonic nanostructures have been studied under the influence of illumination at plasmonic wavelengths (405, and 532 nm). The results revealed to a clear tunable and adjustable optical and thermo-plasmonic properties by controlling the structure of the core/shell NPs. This results can be enhanced by changing the shell thickness, shape, size, and the nanostructure. The temperature elevation of the core/shell NPs was about 1–5 °C under different wavelengths of laser irradiation. Based on those results, there is possibility of using the core/shell nanoparticles as an efficient heat source in many applications, such as in the sterilization and disinfection of medical equipments.