Surface enhanced Raman spectroscopy (SERS) – progress and trends

Surface enhanced Raman spectroscopy (SERS) combines molecular fingerprint specificity with potential single-molecule sensitivity. Therefore, the SERS technique is an attractive tool for sensing of molecules in trace amounts within the field of chemical and biochemical analytics. Since SERS is an ongoing topic, which can be illustrated by the increased number of publications within the last years, this Review article reflects the progress and trends in SERS research in the last ~ 3 years. The main reason why the SERS technique has not been established as a routine analytic technique, despite its high specificity as well as sensitivity, is due to the low reproducibility of the SERS signal. Thus, this review article is dominated by the discussion of the various concepts for generating powerful reproducible SERS-active surfaces. Furthermore the limit of sensitivity in SERS is introduced in the context of single molecule spectroscopy and the calculation of the ‘real’ enhancement factor. In order to shed more light into the SERS underlying molecular processes, the theoretical description of SERS spectra is also a growing research field and will be summarized here. In addition, the recording of SERS spectra is affected by a number of various parameters, such as laser power, integration time and analyte concentration. To benefit from synergies, SERS is combined with other methods such as scanning probe microscopy and microfluidics which illustrates the broad application fields.