Charge Carrier Dynamics in Photocatalytic Hybrid Semiconductor-Metal Nanorods: Crossover from Auger Recombination to Charge Transfer

Yuval Ben-Shahar, John P. Philbin, Francesco Scotognella, Lucia Ganzer, Giulio Cerullo*, Eran Rabani, Uri Banin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Hybrid semiconductor-metal nanoparticles (HNPs) manifest unique, synergistic electronic and optical properties as a result of combining semiconductor and metal physics via a controlled interface. These structures can exhibit spatial charge separation across the semiconductor-metal junction upon light absorption, enabling their use as photocatalysts. The combination of the photocatalytic activity of the metal domain with the ability to generate and accommodate multiple excitons in the semiconducting domain can lead to improved photocatalytic performance because injecting multiple charge carriers into the active catalytic sites can increase the quantum yield. Herein, we show a significant metal domain size dependence of the charge carrier dynamics as well as the photocatalytic hydrogen generation efficiencies under nonlinear excitation conditions. An understanding of this size dependence allows one to control the charge carrier dynamics following the absorption of light. Using a model hybrid semiconductor-metal CdS-Au nanorod system and combining transient absorption and hydrogen evolution kinetics, we reveal faster and more efficient charge separation and transfer under multiexciton excitation conditions for large metal domains compared to small ones. Theoretical modeling uncovers a competition between the kinetics of Auger recombination and charge separation. A crossover in the dominant process from Auger recombination to charge separation as the metal domain size increases allows for effective multiexciton dissociation and harvesting in large metal domain HNPs. This was also found to lead to relative improvement of their photocatalytic activity under nonlinear excitation conditions.

Original languageAmerican English
Pages (from-to)5211-5216
Number of pages6
JournalNano Letters
Issue number8
StatePublished - 8 Aug 2018

Bibliographical note

Funding Information:
We thank Professor Daniel Strasser’s lab from the Institute of Chemistry, The Hebrew University of Jerusalem, for assistance in the photocatalysis measurements. The research leading to these results was supported in part by the Israel Science Foundation − Alternative Fuels Program Center of Excellence (Grant 1867/17). U.B. thanks the Alfred & Erica Larisch memorial chair. Y.B.S. acknowledges support by the Ministry of Science and Technology, Israel & The Camber Scholarship. E.R. acknowledges support from the UC Lab Fee Research Program (Grant LFR-17-477237). U.B. and G.C. acknowledge support from Horizon 2020 (654148, Laserlab-Europe).

Publisher Copyright:
Copyright © 2018 American Chemical Society.


  • Hybrid semiconductor-metal nanoparticles
  • hydrogen evolution
  • multiexcitons
  • photocatalysis


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