Fluorescence suppression and surface-enhanced Raman scattering (SERS) in rhodamine B dye using silver nanowires as SERS substrates
We investigated the fluorescence suppression and surface-enhanced Raman scattering (SERS) in rhodamine B dye using silver nanowires (Ag NWs) as SERS substrates. The Ag NWs were prepared by electroless deposition and subsequently suspended in ethanol. The NWs were deposited on paper and used to detect rhodamine B (RhB) in water to a concentration of 5 µM. Fluorescence and Raman measurements were performed using a micro-Raman spectroscopy setup with a 532 nm excitation. Optical microscope images showed the presence of fluorescent regions where only a few NWs were observed and dark regions where a dense amount of Ag NWs were located. The fluorescence emission centered at ~581 nm was attributed to the RhB dye. A ~75% decrease in the fluorescence emission was observed at the SERS hotspots with Ag NWs. Raman measurements performed at the Ag NW-filled region confirmed that the vibrational modes of RhB were enhanced by a factor of 104. This study demonstrates the feasibility of using Ag NWs to suppress fluorescence in biological or inorganic samples for Raman microscopy.