Silver nanodiscs for enhanced fluorescence emission

Here, we used a novel method to deform silver nanoparticles (Ag NPs) into nanodiscs through the application of transverse mechanical force using a home-built Teflon puncher. The application of 50 N force for 50 times resulted in the formation of Ag nanodiscs (88 nm high, 113 nm wide) from polyhedral Ag NPs (~105 nm diameter). We observed a clear red-shift in the plasmonic resonance for Ag nanodiscs. We show that the fluorescence emission from Rhodamine B (RhB) is enhanced by >30 fold (with respect to RhB on bare glass) in the presence of Ag nanodiscs due to a simultaneous increase in the excitation intensity and photon mode density. The observed increase in Ag nanodiscs is explained in terms of its red-shifted scattering closer to RhB emission, which results in an increased local electric field and higher photonic mode density for Ag nanodiscs.