Picomolar Detection of Rhodamine 6G by SERS Using Silver Nanodendrites Decorated with Au and Cu-Au Bimetallic Nanoparticles

Surface Enhanced Raman Spectroscopy (SERS) has been widely used for the detection of chemicals at trace levels. Recently, the use of metallic and bimetallic SERS substrates has been of great interest due to the increment in the enhancement factors. In the present work, we report a simple, fast, reproducible and low-cost method to obtain silver nanodendrites decorated with Au nanoparticles and bimetallic Cu-Au nanoparticles by electrodeposition, and their use as SERS substrates. The decorated nanostructures were characterized by AFM, SEM and EDX-SEM, showing the growth of silver nanodendrites with multiple long branches and a homogeneous decoration with an average diameter of bimetallic particles of 24 nm. Silver nanostructures decorated with bimetallic nanoparticles were tested by impregnation of Rhodamine 6G (R6G) as analyte to verify its effectiveness as SERS substrate. R6G was detected in picomolar concentration, corresponding to an analytical enhancenment factor of 109.