Controlling the synthesis and assembly of silver nanocrystals for single-molecule detection by SERS

Detecting toxic chemical or biological agents in low concentrations requires a highly specific sensing technique, such as surface-enhanced Raman spectroscopy (SERS). The controlled synthesis of metallic nanocrystals has provided a new class of substrates for more reliable and sensitive SERS applications. The nanocrystal shape plays a major role in designing SERS substrates for maximizing the SERS enhancement factor (EF). Assembling nanocrystals into dimers can further amplify the EF, opening the door to the possibility of single-molecule detection. Here, we briefly discuss our recent work on the synthesis of silver (Ag) nanocrystals and their assembly into dimers and other reliable techniques to form hot spots with sufficiently high EF for single-molecule detection by SERS.