Comparison study of iron and iron-oxide nanoparticles for thermoplasmonic applications

Abstract

The plasmonic nanoparticles have the properties of surface plasmon resonance (SPR) that can be used to heat up the surrounding by absorbing maximum light from an irradiated beam. Therefore, the present study reveals the photothermal effect of iron and iron-oxide nanosphere in different ambient environments with varying radii from 20 nm to 60 nm. Based on Mie’s theory, PyMieLab_V1.0 software is used to calculate the size-dependent absorption cross-section of spherical nanoparticles. The absorption spectra at λmax have been tuned from the UV to Infrared region of Fe nanoparticles in different surrounding environments while for Fe2O3 NPs, it reveals in the UV region. As the nanoparticle size increases, the absorption peak position of Fe and Fe2O3 NPs shifts towards the longer wavelength regime on the electromagnetic spectrum. It has been observed that the heat generation rate and the maximum temperature gradually increase with particle sizes and a 60 nm particle’s size has maximum heat generated as well as a maximum temperature increase further, iron NPs are more dominant than iron oxide NPs. At the resonance wavelength, the near-field enhancement is observed with the nanosphere's radii, but with variation in the value of refractive indices, it decreases. Thus, this simulated work opens potential applications in a newly emerging field like thermo-plasmonic and thermo-optic.