Where Isurface and Ibulk are the intensities of the SERS peak and normal Raman peak respectively, and Nsurface and Nbulk are the number of molecules illuminated by the laser spot on the SERS substrates (surface) and in the 4-ABT powder (volume), respectively. Nsurface and Nbulk were evaluated using data from , see SI for a detailed description on approach used and SEM data to calculate the roughness factor. The enhancement factor of 4-ABT on the silver nanodendrites is calculated to be 3.19 x 10 6 . This is consistent with the EF observed for 3D nanodendrites. Figure Raman spectra of (a) 4-ABT powder and (b) a monolayer of 4-ABT deposited on the silver nanodendrites .