Speaker
Description
The optical response of plasmonic nanostructures can be tuned by varying their shape, size, and chemical composition [1]. Peculiar phenomena arise when a molecular system is adsorbed on the surface of plasmonic materials, ranging from surface-enhanced spectroscopies to photocatalysis [2]. The accurate description of the optical properties of the plasmonic substrates is thus crucial for an understanding of the physical phenomena occurring at the plasmon resonance frequency. Here, we present an atomistic, yet classical, approach to predict the plasmon properties of nanostructures of complex shapes. The method is general enough to describe any plasmonic material, including noble metal nanoparticles (Ag and Au) [3] and metal alloys [4]. The approach is also coupled to a quantum mechanical (QM) description of the molecular system adsorbed on the nanostructure surface [5]. The resulting mixed QM/classical method is then extended to various spectral signals, from surface-enhanced Raman scattering to surface-enhanced fluorescence.
We show that our classical approach for plasmonics can correctly reproduce reference ab initio data [3], and experimental trends [3-4], and can be applied to large-scale nanoplasmonic simulations (more than 1 million atoms). By properly accounting for the atomistic discretization of matter, we can accurately describe the nanoplasmonics of systems dominated by quantum effects, such as subnanometer junctions [3,6], and geometrical defects, such as picocavities [7]. Finally, we discuss the current challenges in the prediction of the light-driven phenomena at plasmonic interfaces by means of atomistic approaches, ranging from surface-enhanced spectroscopies to photocatalysis.
References:
[1] K. L. Kelly et al., J. Phys. Chem. B 2003, 107, 668.
[2] J. Langer et al. ACS Nano 2019, 14, 28.
[3] T. Giovannini et al., ACS Photonics 2022, 9, 3025.
[4] L. Nicoli et al. Front. Photon. 2023, 1199598.
[5] P. Lafiosca et al., J. Chem. Theory Comput., 2023, 19, 3616.
[6] T. Giovannini et al., Nanoscale, 2019, 11, 6004.
[7] T. Giovannini et al. Nano Lett. 2025, 25, 10802.
Acknowledgments
This work has received funding from the ERC under the European Union’s Horizon Europe research and innovation programme (grant no. 101219149, project CHOPIN). Views and opinions expressed are however those of the author only and do not necessarily reflect those of the European Union or ERC Executive Agency. Neither the European Union nor the granting authority can be held responsible for them.