Visualizing Ultrafast Electron Transfer Processes in Semiconductor-Metal Hybrid Nanoparticles: Toward Excitonic-Plasmonic Light Harvesting

Franco V.A. Camargo, Yuval Ben-Shahar, Tetsuhiko Nagahara, Yossef E. Panfil, Mattia Russo, Uri Banin, Giulio Cerullo

Research output: Contribution to journalArticlepeer-review

Abstract

Recently, it was demonstrated that charge separation in hybrid metal-semiconductor nanoparticles (HNPs) can be obtained following photoexcitation of either the semiconductor or of the localized surface plasmon resonance (LSPR) of the metal. This suggests the intriguing possibility of photocatalytic systems benefiting from both plasmon and exciton excitation, the main challenge being to outcompete other ultrafast relaxation processes. Here we study CdSe-Au HNPs using ultrafast spectroscopy with high temporal resolution. We describe the complete pathways of electron transfer for both semiconductor and LSPR excitation. In the former, we distinguish hot and band gap electron transfer processes in the first few hundred fs. Excitation of the LSPR reveals an ultrafast (<30 fs) electron transfer to CdSe, followed by back-transfer from the semiconductor to the metal within 210 fs. This study establishes the requirements for utilization of the combined excitonic-plasmonic contribution in HNPs for diverse photocatalytic applications.

Original languageAmerican English
Pages (from-to)1461-1468
Number of pages8
JournalNano Letters
Volume21
Issue number3
DOIs
StatePublished - 10 Feb 2021

Keywords

  • hot-electron transfer
  • localized surface plasmon resonances
  • photocatalysis
  • semiconductor nanoparticles
  • ultrafast optical spectroscopy

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Condensed Matter Physics
  • Mechanical Engineering
  • Bioengineering
  • General Materials Science

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