Optical Absorption Spectra of Star-Shaped Au-Ag Nanoparticles by Discrete Dipole Approximation Calculation Considering Highly Symmetrical Models

Local surface plasmon resonance occurs depending on the size and morphology of noble metal nanoparticles. This study investigated the identification of spinous morphology of star-shaped Au-Ag nanoparticles by using discrete dipole approximation and morphological symmetric consideration. Star-shaped Au-Ag nanoparticles were prepared by adding ascorbic acid into a mixed solution of gold chloride and silver nitrate. By varying the Au/Ag ratio, nanoparticles with different aspect ratios and number of spines were obtained. Morphology was identified by comparing the optical absorption spectra of the nanoparticles with the absorption efficiency calculated from discrete dipole approximation based on the symmetry of decahedrons, dodecahedrons and icosahedrons. By considering the particle size distribution of the nanoparticles, the calculation accuracy was improved. In conclusion, this study demonstrated the potential of computational morphological identification in predicting nanoparticle with complexed morphology.

Automated summary

This study investigated the identification of star-shaped Au-Ag nanoparticles with spinous morphology using discrete dipole approximation and morphological symmetric consideration. By varying the Au/Ag ratio, nanoparticles with different aspect ratios and number of spines were obtained and their morphology was identified by comparing the optical absorption spectra with the calculated absorption efficiency. Taking the particle size distribution into consideration improved the calculation accuracy. In conclusion, this study demonstrated the potential of computational morphological identification in predicting nanoparticles with complexed morphology.