Visualizing individual molecules with chemical recognition is a longstanding target in catalysis, molecular nanotechnology and biotechnology. Molecular vibrations provide a valuable ‘fingerprint’ for such identification. Vibrational spectroscopy based on tip-enhanced Raman scattering allows us to access the spectral signals of molecular species very efficiently via the strong localized plasmonic fields produced at the tip apex1,2,3,4,5,6,7,8,9,10,11. However, the best spatial resolution of the tip-enhanced Raman scattering imaging is still limited to 3−15 nanometres5,12,13,14,15,16, which is not adequate for resolving a single molecule chemically. Here we demonstrate Raman spectral imaging with spatial resolution below one nanometre, resolving the inner structure and surface configuration of a single molecule. This is achieved by spectrally matching the resonance of the nanocavity plasmon to the molecular vibronic transitions, particularly the downward transition responsible for the emission of Raman photons. This matching is made possible by the extremely precise tuning capability provided by scanning tunnelling microscopy. Experimental evidence suggests that the highly confined and broadband nature of the nanocavity plasmon field in the tunnelling gap is essential for ultrahigh-resolution imaging through the generation of an efficient double-resonance enhancement for both Raman excitation and Raman emission. Our technique not only allows for chemical imaging at the single-molecule level, but also offers a new way to study the optical processes and photochemistry of a single molecule.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Stöckle, R. M., Suh, Y. D., Deckert, V. & Zenobi, R. Nanoscale chemical analysis by tip-enhanced Raman spectroscopy. Chem. Phys. Lett. 318, 131–136 (2000)
Anderson, M. S. Locally enhanced Raman spectroscopy with an atomic force microscope. Appl. Phys. Lett. 76, 3130–3132 (2000)
Hayazawa, N., Inouye, Y., Sekkat, Z. & Kawata, S. Metallized tip amplification of near-field Raman scattering. Opt. Commun. 183, 333–336 (2000)
Pettinger, B., Picardi, G., Schuster, R. & Ertl, G. Surface enhanced Raman spectroscopy: towards single molecular spectroscopy. Electrochem. Jpn. 68, 942–949 (2000)
Anderson, N., Hartschuh, A., Cronin, S. & Novotny, L. Nanoscale vibrational analysis of single-walled carbon nanotubes. J. Am. Chem. Soc. 127, 2533–2537 (2005)
Neacsu, C. C., Dreyer, J., Behr, N. & Raschke, M. B. Scanning-probe Raman spectroscopy with single-molecule sensitivity. Phys. Rev. B 73, 193406 (2006)
Sonntag, M. D. et al. Single-molecule tip-enhanced Raman spectroscopy. J. Phys. Chem. C 116, 478–483 (2012)
Berweger, S. et al. Optical nanocrystallography with tip-enhanced phonon Raman spectroscopy. Nature Nanotechnol. 4, 496–499 (2009)
van Schrojenstein Lantman, E. M., Deckert-Gaudig, T., Mank, A. J. G., Deckert, V. & Weckhuysen, B. M. Catalytic processes monitored at the nanoscale with tip-enhanced Raman spectroscopy. Nature Nanotechnol. 7, 583–586 (2012)
Liu, Z. et al. Revealing the molecular structure of single-molecule junctions in different conductance states by fishing-mode tip-enhanced Raman spectroscopy. Nature Commun. 2, 305 (2011)
Alonso-González, P. et al. Resolving the electromagnetic mechanism of surface-enhanced light scattering at single hot spots. Nature Commun. 3, 684 (2012)
Ichimura, T. et al. Subnanometric near-field Raman investigation in vicinity of a metallic nanostructure. Phys. Rev. Lett. 102, 186101 (2009)
Steidtner, J. & Pettinger, B. Tip-enhanced Raman spectroscopy and microscopy on single dye molecules with 15 nm resolution. Phys. Rev. Lett. 100, 236101 (2008)
Stadler, J., Schmid, T. & Zenobi, R. Nanoscale chemical imaging using top-illumination tip-enhanced Raman spectroscopy. Nano Lett. 10, 4514–4520 (2010)
Yano, T., Verma, P., Saito, Y., Ichimura, T. & Kawata, S. Pressure-assisted tip-enhanced Raman imaging at a resolution of a few nanometres. Nature Photon. 3, 473–477 (2009)
Treffer, R., Lin, X. M., Bailo, E., Deckert-Gaudig, T. & Deckert, V. Distinction of nucleobases—a tip-enhanced Raman approach. Beilstein J. Nanotechnol 2, 628–637 (2011)
Pettinger, B., Schambach, P., Villagómez, C. J. & Scott, N. Tip-enhanced Raman spectroscopy: near-fields acting on a few molecules. Annu. Rev. Phys. Chem. 63, 379–399 (2012)
Berweger, S. & Raschke, M. B. Signal limitations in tip-enhanced Raman scattering: the challenge to become a routine analytical technique. Anal. Bioanal. Chem. 396, 115–123 (2010)
Xu, H. X., Aizpurua, J., Käll, M. & Apell, P. Electromagnetic contributions to single-molecule sensitivity in surface-enhanced Raman scattering. Phys. Rev. E 62, 4318–4324 (2000)
Aizpurua, J., Hoffmann, G., Apell, S. P. & Berndt, R. Electromagnetic coupling on an atomic scale. Phys. Rev. Lett. 89, 156803 (2002)
Jiang, N. et al. Observation of multiple vibrational modes in ultrahigh vacuum tip-enhanced Raman spectroscopy combined with molecular-resolution scanning tunneling microscopy. Nano Lett. 12, 5061–5067 (2012)
Dong, Z. C. et al. Generation of molecular hot electroluminescence by resonant nanocavity plasmons. Nature Photon. 4, 50–54 (2010)
Dong, Z. C. et al. Vibrationally resolved fluorescence from organic molecules near metal surfaces in a scanning tunneling microscope. Phys. Rev. Lett. 92, 086801 (2004)
Stipe, B. C., Rezaei, M. A. & Ho, W. Single-molecule vibrational spectroscopy and microscopy. Science 280, 1732–1735 (1998)
Pettinger, B., Domke, K. F., Zhang, D., Picardi, G. & Schuster, R. Tip-enhanced Raman scattering: influence of the tip-surface geometry on optical resonance and enhancement. Surf. Sci. 603, 1335–1341 (2009)
Itoh, T. et al. Surface-enhanced resonance Raman scattering and background light emission coupled with plasmon of single Ag nanoaggregates. J. Chem. Phys. 124, 134708 (2006)
Yorulmaz, M., Khatua, S., Zijlstra, P., Gaiduk, A. & Orrit, M. Luminescence quantum yield of single gold nanorods. Nano Lett. 12, 4385–4391 (2012)
Kukura, P., McCamant, D. W. & Mathies, R. A. Femtosecond stimulated Raman spectroscopy. Annu. Rev. Phys. Chem. 58, 461–488 (2007)
Wang, X. et al. Tip-enhanced Raman spectroscopy for investigating adsorbed species on a single-crystal surface using electrochemically prepared Au tips. Appl. Phys. Lett. 91, 101105 (2007)
Zhang, C. et al. Fabrication of silver tips for scanning tunneling microscope induced luminescence. Rev. Sci. Instrum. 82, 083101 (2011)
We thank B. Wang, B. Ren, H. X. Xu, Z. Liu, and X. M. Yang for discussions and Unisoku Company for technical assistance. This work is supported by the National Basic Research Program of China, the Strategic Priority Research Program of the Chinese Academy of Sciences, the Natural Science Foundation of China and the Basque Government Project of Excellence (ETORTEK).
The authors declare no competing financial interests.
This file contains Supplementary Figures 1-5, additional references and Supplementary Text and Data sections S1-S6 as follows: S1 Supplementary methods -experimental setup; S2 Supplementary methods - computational models; S3 Spectral comparison and spectral assignment; S4 the role of the tunneling current in the STM-controlled TERS; S5 an “analogue” to the broadband femtosecond stimulated Raman scattering and S6 containing the full Supplementary Video legend. (PDF 1193 kb)
Molecular vibrations of a H2TBPP molecule for representative Raman modes in the calculated spectrum via DFT
This video shows the molecular vibrations of a H2TBPP molecule for those representative Raman modes corresponding to the labeled peaks in Figure 2 for the calculated spectrum via DFT. The symmetry of each mode and a schematic of C2v point-group symmetry for H2TBPP molecule are also shown in this video. (MOV 1837 kb)
About this article
Cite this article
Zhang, R., Zhang, Y., Dong, Z. et al. Chemical mapping of a single molecule by plasmon-enhanced Raman scattering. Nature 498, 82–86 (2013). https://doi.org/10.1038/nature12151
Understanding the Role of Different Substrate Geometries for Achieving Optimum Tip-Enhanced Raman Scattering Sensitivity
Nanoscale Advances (2021)
ACS Photonics (2021)
Methods to fabricate and recycle plasmonic probes for ultrahigh vacuum scanning tunneling microscopy‐based tip‐enhanced Raman spectroscopy
Journal of Raman Spectroscopy (2021)