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 (EF(dimer)) 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, EF(dimer) was insensitive the dimer geometry and corresponded to 2.0×10(7) and 1.5×10(7), respectively. However, EF(dimer) was decreased to 5.6×10(6) 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.