Optical absorption analysis of core-shell type Ni@Ag/Au & NiFe@Ag/Au magneto-plasmonic nanostructures

Highlights: • The optical properties of simple; Ni@Ag/Au and complex; NiFe@Ag/Au magnetoplasmonic nanoparticles for their core-shell structures with spherical and prolate geometries are investigated. • The observed spectra are found between 335 to 717 nm on the wavelength spectrum. • The tunability in core size, shell thickness, aspect ratio, and configuration opens new potential use with desired applications in biomedical fields. The core-shell nanoparticles are greatly advocated for their usefulness in biomedical applications tending to targeted drug delivery, sensing, and bio-imaging. In this paper, the optical properties of simple; Ni@Ag/Au and complex; NiFe@Ag/Au magnetoplasmonic nanoparticles for their core-shell structures with spherical and prolate geometries are comprehensively investigated using the discrete dipole approximation (DDA) method. It is found that the Localized Surface Plasmon Resonance (LSPR) for absorption (λ_max) as well as efficiency (intensity) strongly depend on the geometry of the nanoparticle, aspect ratio, core sizes, and shell thickness. The absorption spectra which are generally found in the 335–717 nm wavelength ranges can be tuned in the ultra violet-near-infrared (UV-NIR) region of the electromagnetic (EM) spectrum for desired biomedical applications. It is discovered that there is a higher tunability of LSPR peak position as well as larger enhancement in the absorption efficiency when the spherical nanoparticle stretches to prolate core-shell configuration. Based on these findings, therefore, it is suggested that the proposed core-shell nanostructures with the tunable optical response in the visible region have potentials in cancer therapy, drug delivery, and optical imaging.