Optical Effects of Triangular Shaped Gold-Iron Nanoparticles

In recent years, there has been an intense interest towards magnetic nanoparticles in data storage, drug targeting or delivery and biomedical applications. The compatibility, stability and optical properties of such nanoparticles can be enhanced by combining them with noble metals. In this study, we calculated the optical properties of Gold-Iron (Au-Fe) alloy nanostructures as a function of size, composition, and surrounding medium by using discrete dipole approximation method. It has been found that the triangular shape nanostructure exhibit enhanced plasmonic properties for suitable particle size and the surrounding medium. The increase in size resulted in shift of localized surface plasmon resonance (LSPR) from ultra-violet (UV) visible to near-infrared (NIR) regions and enhancement in absorption efficiency parameters. The effect of size on full width half maximum (FWHM) has also been analyzed. The comparison of triangular shape nanostructure for different surrounding medium shows that the LSPR λ_max and FWHM have the ordering for the refractive index of n=1.53 > n=1.33 > n=1.00. Thus, the presented results can help in the selection of suitable magneto-plasmonic nanostructures for applications in medical diagnostics, therapeutics, and biological imaging.