Emission behavior of sudan red 7B on dogbone-shaped gold nanorods: Aspect ratio dependence of the metallic nanostructures

•CTAB-stabilized gold dogbones of variable aspect ratio have been synthesized.•Sudan red 7B has been used as fluoroprobe to elucidate aspect ratio dependence of the dogbones.•The relative intensity decreases exponentially with increasing aspect ratio.•The mechanism of quenching has been ascribed to the electron and energy transfer processes.

Cetyltrimethylammonium bromide-stabilized 'dogbone-shaped' gold nanorods of aspect ratio varying from 1 to 6 have been synthesized by seed-mediated growth method in aqueous medium. Then, sudan red 7B, an alien molecular probe has been used as local probe to elucidate aspect ratio dependence of the nanorods on the photophysical properties of the dye molecules. It is seen that the relative intensity decreases exponentially with increasing aspect ratio and has been attributed to decrease in overall surface area for a particular concentration of the nanorods. The mechanism of fluorescence quenching has been ascribed to the electron and energy transfer processes in the gold-fluorophore hybrid nanostructures.

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