Tip-enhanced Raman spectroscopy: From concepts to practical applications

Abstract

Tip-enhanced Raman spectroscopy (TERS) is a powerful technique that integrates the vibrational fingerprinting of Raman spectroscopy and the sub-nanometer resolution of scanning probe microscopy (SPM). As a result, TERS is capable of obtaining chemical maps of analyzed specimens with exceptional lateral resolution. This is extremely valuable for the study of interactions between molecules and substrates, in addition to structural characterization of biological objects, such as viruses and amyloid fibrils, 2D polymeric materials, and monitoring electrochemical and photo-catalytic processes. In this mini-review, we discuss the most significant advances of TERS, including: super high resolution chemical imaging, monitoring of catalytic processes, incorporation of pulsed-excitation techniques, single-site electrochemistry, biosensing, and art conservation. We begin with a short overview of TERS, comparing it with other surface analytical techniques, followed by an overview of recent developments and future applications in TERS.Graphical Abstract:

Electrochemical TERS Elucidates Potential‐Induced Molecular Reorientation of Adenine/Au(111)

“…TERS is based on the combination of an SPM with aR aman optical platform in which am etallic SPM probe located in close vicinity above asurface acts as ananoantenna to create aplasmon-enhanced field and, consequently,strong Raman scattering from adsorbates located in the tip-sample gap at as patial resolution of typically below 10 nm. [10][11][12] While TERS in UHV and ambient conditions is increasingly used in surface science to interrogate adsorbate orientation, [13][14][15][16] the study of solid/liquid interfaces has long remained ah uge technical challenge. [17,18] Extending the technique to spectro-electrochemical experiments requires additional electrical contacting and control of the working electrode under investigation, thus rendering the setup even more complex and technically challenging.…”

Recent advances in hybrid measurement methods based on atomic force microscopy and surface sensitive measurement techniques

“…Therefore, we want to refer the interested reader to the reviews of Kumar et al and Jiang et al, which summarize recent advances in TERS together with its advantages and weaknesses. 240,248 TERS itself is developed further, even though it is already utilized for many applications. Important issues, which are encountered, are low fabrication reproducibility of the AFMtip, which becomes manifest in differing Raman enhancement factor or induced plasmonic dipole factors from tip to tip, 249 short plasmonic lifetimes, which are assigned to metal delamination (Au-tips) or chemical alteration (Ag-tips) 250,251 and low signal-to-noise ratio due to far-eld scattering/emission.…”

Electrochemical TERS Elucidates Potential‐Induced Molecular Reorientation of Adenine/Au(111)

“…Tip‐enhanced Raman spectroscopy (TERS) offers an elegant solution to achieve both the required surface (sub)monolayer chemical sensitivity and nanometer spatial resolution. TERS is based on the combination of an SPM with a Raman optical platform in which a metallic SPM probe located in close vicinity above a surface acts as a nanoantenna to create a plasmon‐enhanced field and, consequently, strong Raman scattering from adsorbates located in the tip–sample gap at a spatial resolution of typically below 10 nm . While TERS in UHV and ambient conditions is increasingly used in surface science to interrogate adsorbate orientation, the study of solid/liquid interfaces has long remained a huge technical challenge .…”