Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Sub-nanometre resolution in single-molecule photoluminescence imaging


Ambitions to reach atomic resolution with light have been a major force in shaping nano-optics, whereby a central challenge is achieving highly localized optical fields. A promising approach employs plasmonic nanoantennas, but fluorescence quenching in the vicinity of metallic structures often imposes a strict limit on the attainable spatial resolution, and previous studies have reached only 8 nm resolution in fluorescence mapping. Here, we demonstrate spatially and spectrally resolved photoluminescence imaging of a single phthalocyanine molecule coupled to nanocavity plasmons in a tunnelling junction with a spatial resolution down to 8 Å and locally map the molecular exciton energy and linewidth at sub-molecular resolution. This remarkable resolution is achieved through an exquisite nanocavity control, including tip-apex engineering with an atomistic protrusion, quenching management through emitter–metal decoupling and sub-nanometre positioning precision. Our findings provide new routes to optical imaging, spectroscopy and engineering of light–matter interactions at sub-nanometre scales.

This is a preview of subscription content

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Sub-nanometre-resolved single-molecule TEPL imaging.
Fig. 2: Evolution of spatial resolution for photon images at different gap distances.
Fig. 3: Revealing the photophysics of ZnPc in a plasmonic nanocavity by tracking the evolution of TEPL intensities at different tip–molecule distances.
Fig. 4: Revealing subtle plasmon–molecule interactions at the sub-molecular level by spectroscopic imaging.

Data availability

The data that support the findings of this study are available from the corresponding authors on reasonable request.

Code availability

The MATLAB codes used for the electromagnetic calculations in this study are available from the corresponding authors on reasonable request.


  1. 1.

    Lewis, A., Isaacson, M., Muray, A. & Harootunian, A. Scanning optical spectral microscopy with 500 Å spatial resolution. Biophys. J. 41, 405a (1983).

    Google Scholar 

  2. 2.

    Pohl, D. W., Denk, W. & Lanz, M. Optical stethoscopy: image recording with resolution λ/20. Appl. Phys. Lett. 44, 651–653 (1984).

    ADS  Google Scholar 

  3. 3.

    Betzig, E. & Chichester, R. J. Single molecules observed by near-field scanning optical microscopy. Science 262, 1422–1425 (1993).

    ADS  Google Scholar 

  4. 4.

    Michaelis, J., Hettich, C., Mlynek, J. & Sandoghdar, V. Optical microscopy using a single-molecule light source. Nature 405, 325–328 (2000).

    ADS  Google Scholar 

  5. 5.

    Frey, H. G., Witt, S., Felderer, K. & Guckenberger, R. High-resolution imaging of single fluorescent molecules with the optical near-field of a metal tip. Phys. Rev. Lett. 93, 200801 (2004).

    ADS  Google Scholar 

  6. 6.

    Anger, P., Bharadwaj, P. & Novotny, L. Enhancement and quenching of single-molecule fluorescence. Phys. Rev. Lett. 96, 113002 (2006).

    ADS  Google Scholar 

  7. 7.

    Kühn, S., Håkanson, U., Rogobete, L. & Sandoghdar, V. Enhancement of single-molecule fluorescence using a gold nanoparticle as an optical nanoantenna. Phys. Rev. Lett. 97, 017402 (2006).

    ADS  Google Scholar 

  8. 8.

    Ma, Z., Gerton, J. M., Wade, L. A. & Quake, S. R. Fluorescence near-field microscopy of DNA at sub-10 nm resolution. Phys. Rev. Lett. 97, 260801 (2006).

    ADS  Google Scholar 

  9. 9.

    Höppener, C., Lapin, Z. J., Bharadwaj, P. & Novotny, L. Self-similar gold-nanoparticle antennas for a cascaded enhancement of the optical field. Phys. Rev. Lett. 109, 017402 (2012).

    ADS  Google Scholar 

  10. 10.

    Mauser, N. & Hartschuh, A. Tip-enhanced near-field optical microscopy. Chem. Soc. Rev. 43, 1248–1262 (2014).

    Google Scholar 

  11. 11.

    Weisenburger, S. & Sandoghdar, V. Light microscopy: an ongoing contemporary revolution. Contemp. Phys. 56, 123–143 (2015).

    ADS  Google Scholar 

  12. 12.

    Hermann, R. J. & Gordon, M. J. Nanoscale optical microscopy and spectroscopy using near-field probes. Annu. Rev. Chem. Biomol. Eng. 9, 365–387 (2018).

    Google Scholar 

  13. 13.

    Park, K.-D., Jiang, T., Clark, G., Xu, X. & Raschke, M. B. Radiative control of dark excitons at room temperature by nano-optical antenna-tip Purcell effect. Nat. Nanotechnol. 13, 59–64 (2018).

    ADS  Google Scholar 

  14. 14.

    Gerton, J. M., Wade, L. A., Lessard, G. A., Ma, Z. & Quake, S. R. Tip-enhanced fluorescence microscopy at 10 nanometer resolution. Phys. Rev. Lett. 93, 180801 (2004).

    ADS  Google Scholar 

  15. 15.

    Agio, M. & Alù, A. Optical Antennas (Cambridge Univ. Press, 2013).

  16. 16.

    Matsuzaki, K. et al. Strong plasmonic enhancement of biexciton emission: controlled coupling of a single quantum dot to a gold nanocone antenna. Sci. Rep. 7, 42307 (2017).

    ADS  Google Scholar 

  17. 17.

    Chikkaraddy, R. et al. Mapping nanoscale hotspots with single-molecule emitters assembled into plasmonic nanocavities using DNA origami. Nano Lett. 18, 405–411 (2018).

    ADS  Google Scholar 

  18. 18.

    Groß, H., Hamm, J. M., Tufarelli, T., Hess, O. & Hecht, B. Near-field strong coupling of single quantum dots. Sci. Adv. 4, eaar4906 (2018).

    ADS  Google Scholar 

  19. 19.

    Chen, X. et al. Modern scattering-type scanning near-field optical microscopy for advanced material research. Adv. Mater. 31, 1804774 (2019).

    Google Scholar 

  20. 20.

    Park, K.-D. et al. Tip-enhanced strong coupling spectroscopy, imaging, and control of a single quantum emitter. Sci. Adv. 5, eaav5931 (2019).

    ADS  Google Scholar 

  21. 21.

    Becker, S. F. et al. Gap-plasmon-enhanced nanofocusing near-field microscopy. ACS Photon. 3, 223–232 (2016).

    Google Scholar 

  22. 22.

    Zhang, R. et al. Chemical mapping of a single molecule by plasmon-enhanced Raman scattering. Nature 498, 82–86 (2013).

    ADS  Google Scholar 

  23. 23.

    Lee, J., Crampton, K. T., Tallarida, N. & Apkarian, V. A. Visualizing vibrational normal modes of a single molecule with atomically confined light. Nature 568, 78–82 (2019).

    ADS  Google Scholar 

  24. 24.

    Zhang, Y. et al. Visually constructing the chemical structure of a single molecule by scanning Raman picoscopy. Natl Sci. Rev. 6, 1169–1175 (2019).

    Google Scholar 

  25. 25.

    Benz, F. et al. Single-molecule optomechanics in “picocavities”. Science 354, 726–729 (2016).

    ADS  Google Scholar 

  26. 26.

    Barbry, M. et al. Atomistic near-field nanoplasmonics: reaching atomic-scale resolution in nanooptics. Nano Lett. 15, 3410–3419 (2015).

    ADS  Google Scholar 

  27. 27.

    Dulkeith, E. et al. Fluorescence quenching of dye molecules near gold nanoparticles: radiative and nonradiative effects. Phys. Rev. Lett. 89, 203002 (2002).

    ADS  Google Scholar 

  28. 28.

    Huang, Y. P. et al. Shell-isolated tip-enhanced Raman and fluorescence spectroscopy. Angew. Chem. 130, 7645–7649 (2018).

    Google Scholar 

  29. 29.

    Zhang, F. L. et al. Elucidating molecule–plasmon interactions in nanocavities with 2 nm spatial resolution and at the single-molecule level. Angew. Chem. 131, 12261–12265 (2019).

    Google Scholar 

  30. 30.

    Kinkhabwala, A. et al. Large single-molecule fluorescence enhancements produced by a bowtie nanoantenna. Nat. Photon. 3, 654–657 (2009).

    ADS  Google Scholar 

  31. 31.

    Russell, K. J., Liu, T.-L., Cui, S. & Hu, E. L. Large spontaneous emission enhancement in plasmonic nanocavities. Nat. Photon. 6, 459–462 (2012).

    ADS  Google Scholar 

  32. 32.

    Belacel, C. et al. Controlling spontaneous emission with plasmonic optical patch antennas. Nano Lett. 13, 1516–1521 (2013).

    ADS  Google Scholar 

  33. 33.

    Faggiani, R. M., Yang, J. & Lalanne, P. Quenching, plasmonic, and radiative decays in nanogap emitting devices. ACS Photon. 2, 1739–1744 (2015).

    Google Scholar 

  34. 34.

    Kongsuwan, N. et al. Suppressed quenching and strong-coupling of purcell-enhanced single-molecule emission in plasmonic nanocavities. ACS Photon. 5, 186–191 (2018).

    Google Scholar 

  35. 35.

    Qiu, X., Nazin, G. & Ho, W. Vibrationally resolved fluorescence excited with submolecular precision. Science 299, 542–546 (2003).

    ADS  Google Scholar 

  36. 36.

    Zhang, Y. et al. Visualizing coherent intermolecular dipole–dipole coupling in real space. Nature 531, 623–627 (2016).

    ADS  Google Scholar 

  37. 37.

    Imada, H. et al. Real-space investigation of energy transfer in heterogeneous molecular dimers. Nature 538, 364–367 (2016).

    ADS  Google Scholar 

  38. 38.

    Kuhnke, K., Grosse, C., Merino, P. & Kern, K. Atomic-scale imaging and spectroscopy of electroluminescence at molecular interfaces. Chem. Rev. 117, 5174–5222 (2017).

    Google Scholar 

  39. 39.

    Doppagne, B. et al. Electrofluorochromism at the single-molecule level. Science 361, 251–255 (2018).

    ADS  Google Scholar 

  40. 40.

    Kimura, K. et al. Selective triplet exciton formation in a single molecule. Nature 570, 210–213 (2019).

    ADS  Google Scholar 

  41. 41.

    Doppagne, B. et al. Single-molecule tautomerization tracking through space-and time-resolved fluorescence spectroscopy. Nat. Nanotechnol. 15, 207–211 (2020).

    ADS  Google Scholar 

  42. 42.

    Haroche, S. & Raimond, J.-M. Exploring The Quantum: Atoms, Cavities, and Photons (Oxford Univ. Press, 2006).

  43. 43.

    Zhang, Y. et al. Sub-nanometre control of the coherent interaction between a single molecule and a plasmonic nanocavity. Nat. Commun. 8, 15225 (2017).

    ADS  Google Scholar 

  44. 44.

    Chen, C., Chu, P., Bobisch, C., Mills, D. & Ho, W. Viewing the interior of a single molecule: vibronically resolved photon imaging at submolecular resolution. Phys. Rev. Lett. 105, 217402 (2010).

    ADS  Google Scholar 

  45. 45.

    Neuman, T. S., Esteban, R., Casanova, D., García-Vidal, F. J. & Aizpurua, J. Coupling of molecular emitters and plasmonic cavities beyond the point-dipole approximation. Nano Lett. 18, 2358–2364 (2018).

    ADS  Google Scholar 

  46. 46.

    Rendell, R. & Scalapino, D. Surface plasmons confined by microstructures on tunnel junctions. Phys. Rev. B 24, 3276–3294 (1981).

    ADS  Google Scholar 

  47. 47.

    Savage, K. J. et al. Revealing the quantum regime in tunnelling plasmonics. Nature 491, 574–577 (2012).

    ADS  Google Scholar 

  48. 48.

    Schmaus, S. et al. Giant magnetoresistance through a single molecule. Nat. Nanotechnol. 6, 185–189 (2011).

    ADS  Google Scholar 

  49. 49.

    Kalkbrenner, T. et al. Optical microscopy via spectral modifications of a nanoantenna. Phys. Rev. Lett. 95, 200801 (2005).

    ADS  Google Scholar 

  50. 50.

    Novotny, L. & Hecht, B. Principles of Nano-Optics (Cambridge Univ. Press, 2012).

  51. 51.

    Hecht, B., Bielefeldt, H., Inouye, Y., Pohl, D. & Novotny, L. Facts and artifacts in near-field optical microscopy. J. Appl. Phys. 81, 2492–2498 (1997).

    ADS  Google Scholar 

Download references


We thank B. Wang for helpful discussions. This work was supported by the National Key R&D Program of China (grant numbers 2016YFA0200600 and 2017YFA0303500), the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences (grant number XDB36000000) and the Anhui Initiative in Quantum Information Technologies. J.A. acknowledges project IT1164-19 of the consolidated university groups from the Basque Government.

Author information




Z.D. and J.G.H. conceived and supervised the project. B.Y., A.G., Yufan Zhang and Yang Zhang performed experiments and analysed data. G.C. and Yao Zhang derived the theory and performed theoretical simulations. B.Y., G.C., Yao Zhang, Yang Zhang, Y.L., J.Y., V.S., J.A., Z.D. and J.G.H contributed to the data interpretation. Z.D., B.Y., G.C., Yang Zhang, J.A., V.S. and J.G.H. co-wrote the manuscript. All authors discussed the results and commented on the manuscript.

Corresponding authors

Correspondence to Yang Zhang, Zhenchao Dong or J. G. Hou.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

Extended Data Fig. 1 Schematic drawing of our custom-built experimental setup for TEPL measurements.

This setup is composed of four sub-systems: a laser source for light excitation, a dark-box for optical filtering, polarization control and alignment, a low-temperature UHV STM for sample preparation and characterization with a built-in lens for both light excitation and collection, and a photon detection sub-system containing a SPAD for PL intensity measurements and a spectrometer equipped with a highly sensitive CCD detector for PL spectral measurements.

Supplementary information

Supplementary Information

Supplementary Sections 1–7.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Yang, B., Chen, G., Ghafoor, A. et al. Sub-nanometre resolution in single-molecule photoluminescence imaging. Nat. Photonics 14, 693–699 (2020).

Download citation

Further reading


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing