Surface-enhanced spectroscopies

Surfaces and interfaces play crucial rules in nature and technology. Understanding the structures both at the actual interface and in the bulk of the participating phases – whether they are liquid or solid or even gaseous – is fundamentally necessary and interesting; without this knowledge, the next step – understanding the dynamics of processes at these interfaces – is impossible in most cases. Scientists facing these challenges are well-equipped with a rich arsenal of experimental methods based mostly on the interaction with probes (beams of particles, electromagnetic radiation, electric and magnetic fields etc.) with matter and the signals generated by the interaction. Frequently these methods are based on techniques initially developed and refined for the use of bulk samples. Popular examples are infrared, Raman, UV-Vis spectroscopy and mass spectrometry to name a few. Transferring these methods to surfaces creates a major challenge: the number of species possibly interacting with the probe decreases dramatically. This creates significant challenges regarding the sensitivity of the corresponding technique. The discovery of huge enhancement of infrared absorption by Hartstein¹ and Raman scattering by Fleischmann² caused by local enhancement of the electric field at metallic nanostructures has changed the prospects of numerous surface spectroscopies dramatically. Very early on, the influence of various factors on the recorded data became obvious as illustrated below with particular attention to surface-enhanced Raman spectroscopy:

In this journal previously, an overview on plasmonics and spectroscopy has been provided dealing with a subset of the methods and phenomena covered in the present issue; for an introduction, see ref. 4. On the occasion of a recent conference, Surface-Enhanced Spectroscopies 2014 (SES 2014) (Chemnitz, Technische Universität Chemnitz, August 7^th–10^th, 2014), an attempt was made to cover the field from fundamentals and modelling to applications in numerous fields. Starting with this survey, the editors of this themed issue have collected contributions covering the range of the topic beyond this conference.

Thanks are due to the reviewers executing their work in the background providing helpful suggestions and constructive criticism to the authors. Thanks are due to the editorial staff handling this issue in a time of transformation at the editorial office, and thanks are due to the Deutsche Bunsen-Gesellschaft für Physikalische Chemie providing the initial input to assemble this issue. The assistance in various ways (including a financial one by several organizations DFG, RSC, TUC and further companies) and by many supporting people is gratefully acknowledged.

References

1. A. Hartstein, J. R. Kirtley and J. C. Tsang, Phys. Rev. Lett., 1980, 45, 201.
2. M. Fleischmann, P. J. Hendra and A. J. McQuillan, Chem. Phys. Lett., 1974, 26, 163.
3. M. Culha, Appl. Spectrosc., 2013, 67, 355.
4. R. F. Aroca, Phys. Chem. Chem. Phys., 2013, 15, 5355.

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