Amplification of Photochemical Chiroptical Activity of Chiral Gold Nanocubes

ORAL

Abstract

We study polarization-dependent plasmonic photochemistry on chiral gold nanocubes (AuNCs) in the presence of 8-Bromoadenine surrounding molecules. The AuNCs exhibit substantial optical activity and a pronounced localized surface plasmon resonance. The hot electron induced dehalogenation of 8-Bromoadenine, adsorbed on chiral AuNCs, has been employed as a model reaction to understand the effect of polarized light on plasmon-induced chemical reactions. Our observations reveal a circular dichroism (CD) of the hot electron generation efficiency resulting in asymmetric reaction rates. The photochemical g-factor surpasses the optical g-factor by a factor of 2. Moreover, a reversal of photochemical CD is observed on multilayer coverage of particles, which is laser power dependent and allows for a further amplification of g-factor just by increasing the light intensity. Calculations of extinction spectra and hot electron generation maps with different polarization incidence on the chiral AuNCs confirm a significant influence of the arrangement of particles on the g-factor. This work opens a new domain in asymmetric photocatalysis.

S. K. Gahlaut et al, Small 21, 2505093 (2025), DOI: 10.1002/smll.202505093

*We thank the German Research Foundation (DFG) for support through CRC 1636 – Project ID 510943930 - Project No. A02 and B03. SR and SJ acknowledge the European Research Council (ERC) under grant DarkSERS (772108).

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Publication: S. K. Gahlaut et al, Small 21, 2505093 (2025), DOI: 10.1002/smll.202505093

Presenters

  • Oscar R Avalos-Ovando

    • University of North Carolina Greensboro

Authors

  • Oscar R Avalos-Ovando

    • University of North Carolina Greensboro

  • Shashank K Gahlaut

    • Institute of Chemistry, University of Potsdam, Postdam

  • Ryeong Myeong Kim

    • Department of Materials Science and Engineering, Seoul National University, Seoul

  • Ridwan Hussein

    • Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio

  • Sabrina Juergensen

    • Department of Physics, Freie University Berlin, Berlin

  • Stephanie Reich

    • Department of Physics, Freie University Berlin, Berlin

  • Alexander O Govorov

    • Department of Physics and Astronomy, Nanoscale and Quantum Phenomena Institute, Ohio University, Athens, Ohio

  • Ki Tae Nam

    • Department of Materials Science and Engineering, Seoul National University, Seoul

  • Ilko Bald

    • Institute of Chemistry, University of Potsdam, Potsdam