Measuring the SERS enhancement factors of dimers with different structures constructed from silver nanocubes

We describe a systematic investigation on the SERS enhancement factors of individual dimers (EFdimer) constructed from two Ag nanocubes that display a face-to-face, edge-to-face, or edge-to-edge structure. The highest field-enhancements were obtained for the dimers displaying a face-to-face and edge-to-face configuration. In these two systems, EFdimer was insensitive the dimer geometry and corresponded to 2.0 × 107 and 1.5 × 107, respectively. However, EFdimer was decreased to 5.6 × 106 for the edge-to-edge structure. These variations in the detected field-enhancements could be explained based on the relative orientation of the nanocubes and the number of probe molecules enclosed in the hot-spot region for each dimer configuration.