Optical response of noble metal alloy nanostructures

• The optical response of alloy nanostructures has been studied by discrete dipole approximation.
• Sharp corner nanostructures show enhanced plasmonic properties.
• Nanobars may be preferred over other nanostructures for absorption-based plasmonic applications.
• Nanocubes of edge length greater than 100 nm may be useful for plasmonic solar cells.
• Rectangular and nanobar particles may be preferred over nanocubes in plasmon sensing.

The optical response, stability, and cost-effectiveness of individual noble metals can be improved by combining them to form alloy nanostructures. The present work reveals the influence of shape, size, and metal type on the optical response of alloy nanoparticles using discrete dipole approximation (DDA) simulations. It is found that sharp corner nanostructures show enhanced plasmonic properties in comparison to rounded counterpart. For all the three shapes, viz., nanocubes, rectangular, and nanobar particles, the increase in length resulted in redshifts of the longitudinal plasmon resonance alongwith enhancement in the scattering yield as well as relative efficiency parameters except for nanocubes of edge length 120 nm. The effect of size on full width at half maxima (FWHM) has also been studied and found to be maximal for nanocubes in comparison to other nanostructures.