Plasmonic coupling at a metal/semiconductor interface

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Integrating plasmonic nanoparticles with semiconductor substrates introduces strong optical resonances that extend and enhance the spectrum of photocatalytic and photovoltaic activity. The effect of plasmonic resonances has been variously attributed to the field nanoconfinement, plasmon–exciton coupling, hot electron transfer, and so on, based on action spectra of enhanced photoactivity. It remains unclear, however, whether energized carriers in the substrate are generated by the transfer of plasmonically generated hot electrons from the metal, as broadly believed, or directly by dephasing of the plasmonic field at the interface. Here, we demonstrate the importance of the direct plasmonic coupling across the chemical interface for hot electron generation at a prototypical Ag nanocluster/TiO2 heterojunction by direct probing of the coherence and hot electron dynamics with two-photon photoemission spectroscopy. Energy, time and material distributions of excitations in the Ag nanocluster/TiO2 heterojunction indicate that dielectric coupling with the substrate renormalizes the plasmon resonance of the Ag nanoparticle, and its dephasing directly generates hot electrons in TiO2 on a <10 fs timescale.

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  1. 1.

    Watanabe, K., Menzel, D., Nilius, N. & Freund, H.-J. Photochemistry on metal nanoparticles. Chem. Rev. 106, 4301–4320 (2006).

  2. 2.

    Linic, S., Christopher, P. & Ingram, D. B. Plasmonic–metal nanostructures for efficient conversion of solar to chemical energy. Nat. Mater. 10, 911–921 (2011).

  3. 3.

    Thomann, I. et al. Plasmon enhanced solar-to-fuel energy conversion. Nano Lett. 11, 3440–3446 (2011).

  4. 4.

    Ingram, D. B., Christopher, P., Bauer, J. L. & Linic, S. Predictive model for the design of plasmonic metal/semiconductor composite photocatalysts. ACS Catal. 1, 1441–1447 (2011).

  5. 5.

    Hou, W. et al. Photocatalytic conversion of CO2 to hydrocarbon fuels via plasmon-enhanced absorption and metallic interband transitions. ACS Catal. 1, 929–936 (2011).

  6. 6.

    Warren, S. C. & Thimsen, E. Plasmonic solar water splitting. Energ. Environ. Sci. 5, 5133–5146 (2012).

  7. 7.

    Du, L., Furube, A., Hara, K., Katoh, R. & Tachiya, M. Ultrafast plasmon induced electron injection mechanism in gold–TiO2 nanoparticle system. J. Photochem. Photobio. C 15, 21–30 (2013).

  8. 8.

    Clavero, C. Plasmon-induced hot-electron generation at nanoparticle/metal-oxide interfaces for photovoltaic and photocatalytic devices. Nat. Photon. 8, 95–103 (2014).

  9. 9.

    Cushing, S. K. & Wu, N. Progress and perspectives of plasmon-enhanced solar energy conversion. J. Phys. Chem. Lett. 7, 666–675 (2016).

  10. 10.

    Ma, X.-C., Dai, Y., Yu, L. & Huang, B.-B. Energy transfer in plasmonic photocatalytic composites. Light. Sci. Appl 5, e16017 (2016).

  11. 11.

    Achermann, M. Exciton−plasmon interactions in metal−semiconductor nanostructures. J. Phys. Chem. Lett. 1, 2837–2843 (2010).

  12. 12.

    Hägglund, C. & Apell, S. P. Plasmonic near-field absorbers for ultrathin solar cells. J. Phys.Chem. Lett. 3, 1275–1285 (2012).

  13. 13.

    Long, R. & Prezhdo, O. V. instantaneous generation of charge-separated state on TiO2 surface sensitized with plasmonic nanoparticles. J. Am. Chem. Soc. 136, 4343–4354 (2014).

  14. 14.

    Wu, K., Chen, J., McBride, J. R. & Lian, T. Efficient hot-electron transfer by a plasmon-induced interfacial charge-transfer transition. Science 349, 632–635 (2015).

  15. 15.

    Li, J. et al. Plasmon-induced resonance energy transfer for solar energy conversion. Nat. Photon. 9, 601–607 (2015).

  16. 16.

    Boerigter, C., Campana, R., Morabito, M. & Linic, S. Evidence and implications of direct charge excitation as the dominant mechanism in plasmon-mediated photocatalysis. Nat. Commun. 7, 10545 (2016).

  17. 17.

    Tan, S. et al. Ultrafast plasmon-enhanced hot electron generation at Ag nanocluster/graphite heterojunctions. J. Am. Chem. Soc. 139, 6160–6168 (2017).

  18. 18.

    Petek, H. Photoexcitation of adsorbates on metal surfaces: one-step or three-step. J. Chem. Phys. 137, 091704–091711 (2012).

  19. 19.

    Kubo, A. et al. Femtosecond imaging of surface plasmon dynamics in a nanostructured silver film. Nano Lett. 5, 1123–1127 (2005).

  20. 20.

    Saavedra, J. R. M., Asenjo-Garcia, A. & García de Abajo, F. J. Hot-electron dynamics and thermalization in small metallic nanoparticles. ACS Photon 3, 1637–1646 (2016).

  21. 21.

    Govorov, A. O., Zhang, H. & Gun’ko, Y. K. Theory of photoinjection of hot plasmonic carriers from metal nanostructures into semiconductors and surface molecules. J. Phys. Chem. C 117, 16616–16631 (2013).

  22. 22.

    Leenheer, A. J., Narang, P., Lewis, N. S. & Atwater, H. A. Solar energy conversion via hot electron internal photoemission in metallic nanostructures: Efficiency estimates. J. Appl. Phys. 115, 134301 (2014).

  23. 23.

    Persson, B. N. J. Polarizability of small spherical metal particles: influence of the matrix environment. Surf. Sci. 281, 153–162 (1993).

  24. 24.

    Hövel, H., Fritz, S., Hilger, A., Kreibig, U. & Vollmer, M. Width of cluster plasmon resonances: Bulk dielectric functions and chemical interface damping. Phys. Rev. B 48, 18178–18188 (1993).

  25. 25.

    Foerster, B. et al. Chemical interface damping depends on electrons reaching the surface. ACS Nano 11, 2886–2893 (2017).

  26. 26.

    Kelly, K. L., Coronado, E., Zhao, L. L. & Schatz, G. C. The optical properties of metal nanoparticles: the influence of size, shape, and dielectric environment. J. Phys. Chem. B 107, 668–677 (2003).

  27. 27.

    Lazzari, R., Jupille, J., Cavallotti, R. & Simonsen, I. Model-free unraveling of supported nanoparticles plasmon resonance modes. J. Phys. Chem. C 118, 7032–7048 (2014).

  28. 28.

    Cai, Y. & Feng, Y. P. Review on charge transfer and chemical activity of TiO2: Mechanism and applications. Prog. Surf. Sci. 91, 183–202 (2016).

  29. 29.

    Argondizzo, A. et al. Ultrafast multiphoton pump-probe photoemission excitation pathways in rutile TiO2. Phys. Rev. B 91, 155429 (2015).

  30. 30.

    Argondizzo, A., Tan, S. & Petek, H. Resonant two-photon photoemission from Ti 3d defect states of TiO2(110) revisited. J. Phys. Chem. C 120, 12959–12966 (2016).

  31. 31.

    Lai, X., Clair, T. P. S., Valden, M. & Goodman, D. W. Scanning tunneling microscopy studies of metal clusters supported on TiO2 (110): Morphology and electronic structure. Prog. Surf. Sci. 59, 25–52 (1998).

  32. 32.

    Chen, D. A., Bartelt, M. C., Seutter, S. M. & McCarty, K. F. Small, uniform, and thermally stable silver particles on TiO2(110)-(1×1). Surf. Sci. 464, L708–L714 (2000).

  33. 33.

    Nilius, N., Ernst, N. & Freund, H. J. On energy transfer processes at cluster–oxide interfaces: silver on titania. Chem. Phys. Lett. 349, 351–357 (2001).

  34. 34.

    Tong, X. et al. The nucleation sites of Ag clusters grown by vapor deposition on a TiO2(110)-1×1 surface. Surf. Sci. 575, 60–68 (2005).

  35. 35.

    Evers, F., Rakete, C., Watanabe, K., Menzel, D. & Freund, H.-J. Two-photon photoemission from silver nanoparticles on thin alumina films: Role of plasmon excitation. Surf. Sci. 593, 43–48 (2005).

  36. 36.

    Nakamura, T., Hirata, N., Sekino, Y., Nagaoka, S. & Nakajima, A. Photoemission enhancement induced by near-fields via local surface plasmon resonance of silver nanoparticles on a hydrogen-terminated Si(111) surface. J. Phys. Chem. C 114, 16270–16277 (2010).

  37. 37.

    Tan, S., Argondizzo, A., Wang, C., Cui, X. & Petek, H. Ultrafast multiphoton thermionic photoemission from graphite. Phys. Rev. X 7, 011004 (2017).

  38. 38.

    Monreal, R. C., Antosiewicz, T. J. & Apell, S. P. Competition between surface screening and size quantization for surface plasmons in nanoparticles. New J. Phys. 15, 083044 (2013).

  39. 39.

    Chiodo, L. et al. Self-energy and excitonic effects in the electronic and optical properties of TiO2 crystalline phases. Phys. Rev. B 82, 045207 (2010).

  40. 40.

    Jin, D. et al. Quantum-spillover-enhanced surface-plasmonic absorption at the interface of silver and high-index dielectrics. Phys. Rev. Lett. 115, 193901 (2015).

  41. 41.

    Lazzari, R., Jupille, J. & Layet, J.-M. Electron-energy-loss channels and plasmon confinement in supported silver particles. Phys. Rev. B 68, 045428 (2003).

  42. 42.

    Amtout, A. & Leonelli, R. Optical properties of rutile near its fundamental band gap. Phys. Rev. B 51, 6842 (1995).

  43. 43.

    Martin, D., Jupille, J. & Borensztein, Y. Silver particle sizes and shapes as determined during a deposit by in situ surface differential reflectance. Surf. Sci. 402–404, 433–436 (1998).

  44. 44.

    Byl, O. & Yates, J. T. Anisotropy in the electrical conductivity of rutile TiO2 in the (110) plane. J. Phys. Chem. B 110, 22966–22967 (2006).

  45. 45.

    Cui, X. et al. Transient excitons at metal surfaces. Nat. Phys. 10, 505–509 (2014).

  46. 46.

    Onda, K. et al. Wet electrons at the H2O/TiO2(110) surface. Science 308, 1154–1158 (2005).

  47. 47.

    Zhukov, V. P. & Chulkov, E. V. Ab initio approach to the excited electron dynamics in rutile and anatase TiO2. J. Phys. Condens. Matter 22, 435802 (2010).

  48. 48.

    Echenique, P. M., Pitarke, J. M., Chulkov, E. V. & Rubio, A. Theory of inelastic lifetimes of low-energy electrons in metals. Chem. Phys. 251, 1–35 (2000).

  49. 49.

    Bauer, M., Marienfeld, A. & Aeschlimann, M. Hot electron lifetimes in metals probed by time-resolved two-photon photoemission. Prog. Surf. Sci. 90, 319–376 (2015).

  50. 50.

    Kresse, G. & Hafner, J. Ab initio molecular dynamics for open-shell transition metals. Phys. Rev. B 48, 13115–13118 (1993).

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The experimental research was supported by a grant from the NSF (CHE-1414466) and the theory by grants from the NSFC (11620101003, 21421063, 91421313), and National Key Basic Research Program of China (2016YFA0200604, 2017YFA0204904). A.A. was supported by a Fellowship from the Pittsburgh Quantum Institute. The calculations were performed at the Supercomputer Center and Environmental Molecular Sciences Laboratory at PNNL, a user facility sponsored by the DOE Office of Biological and Environmental Research, and the supercomputing centre at USTC. The authors thank A. Sirjoosingh, G. Schatz and R. Lazzari for discussion on the dielectric interactions between Ag nanoclusters and TiO2 substrate.

Author information


  1. Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, PA, USA

    • Shijing Tan
    • , Adam Argondizzo
    • , Jindong Ren
    • , Jin Zhao
    •  & Hrvoje Petek
  2. ICQD/Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui, China

    • Jin Zhao
  3. Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, University of Science and Technology of China, Hefei, Anhui, China

    • Jin Zhao
  4. Department of Physics, University of Science and Technology of China, Hefei, Anhui, China

    • Liming Liu
    •  & Jin Zhao
  5. Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui, China

    • Jin Zhao


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S.T. performed the experiments and wrote the first draft of the manuscript. A.A. set up the experimental apparatus and assisted in the laser operation. J.R. performed the analysis of STM measurements. L.L. performed the theoretical calculations. J.Z. supervised and helped to interpret the calculations. H.P. conceived the experiment, supervised its execution, and finalized the manuscript.

Competing interests

The authors declare no competing financial interests.

Corresponding authors

Correspondence to Jin Zhao or Hrvoje Petek.

Electronic supplementary material

  1. Supplementary Information

    Supplementary characterization and analysis information