1 Facile tuning of plasmon bands in hollow silver nanoshells using mild reductant and mild stabilizer Satarupa Pattanayak a , Amiya Priyam a, * and Pradip Paik b,c Supplementary Information Optimization of synthesis temperature Figure S1. The effect of synthesis temperature on the UV-Vis spectra of silver nanoparticles prepared by reduction of Ag 2 O NPs at basic pH. (Stabilizer : citrate; Reducing agent :hydrazine hydrate) The reduction of Ag 2 O NPs was carried out at different temperatures using hydrazine hydrate as reducing agent. In this experiment, there are two oppositely moving ‘diffusion-reaction’ fronts and the temperature at which the both become comparable to each other, hollow structures are likely to be formed. Spectroscopically, the formation of hollow plasmonic nanostructures is indicated by the red- shift in the plasmon peak. The SPR peak is observed at 409 nm for the syntheses at 10 o C, 15 o C and 25 o C. But, the peak red-shifts to 423 nm at 20 o C. As the maximum redshift is observed at 20 o C, this is chosen as the synthesis temperature for rest of the experiments. Electronic Supplementary Material (ESI) for Dalton Transactions This journal is © The Royal Society of Chemistry 2013