Lemon-Juice-Based Microwave Synthesis and Optical Characterization of Anisotropic Gold Nanoparticles

Anisotropic gold nanoparticles (AuNPs) were synthesized using microwave (MW)-assisted route. Lemon extract was used as both reducing and stabilizing agent. Subsequent UV treatment was carried out to modify the particle size and shape. Distribution of triangular and pentagonal-shaped particles were found to increase in number. Moreover, up to 60% increase in particle size was also observed. Change in optical property and appearance of plasmon modes were clear indication of the modification caused. Local density of photonic states (LDOS) and electric field distribution were obtained through computational simulation using MATLAB toolbox. Experimental results were used as the input values for the simulation. Dipolar distribution was observed along the boundaries of the spherical NPs, while for triangular and pentagonal-shaped NPs, they were found to be concentrated along their edges and corners. The results presented here encourage us to choose an alternative eco-friendly, quick and simple route to synthesize gold NPs of various shapes for various application such as in viral detection, nanobiomaterials, biomedical images, detection-therapy, etc. New, rapid, and eco-friendly route to synthesize anisotropic gold nanoparticles (AuNPs) using microwave-assisted method is proposed. Subsequent UV treatment of the synthesized AuNPs did modify their size and shape. An increase in their size of up to 60% was recorded along with the change in their shape from spheroidal to triangular, pyramidal, and pentagonal. Plasmonic peaks obtained experimentally were used in theoretical study to understand the distribution of electrical fields. Using simulated results, the dominant geometric contributions of the plasmon resonances were mapped.