Plasmon-Enhanced Photocatalysis for Sustainability

Plasmons can serve as efficient generators of hot electrons and holes that can be exploited in light harvesting applications. The physical mechanism for plasmon-induced hot carrier generation is plasmon decay. Plasmons can decay either radiatively or non-radiatively with a branching ratio that can be controlled by tuning the radiance of the plasmon mode. Non-radiative plasmon decay is a quantum mechanical process in which one plasmon quantum is transferred to the conduction electrons of the nanostructure by creating an electron-hole pair, i.e., excitation of an electron below the Fermi level of the metal into a state above the Fermi level but below the vacuum level. These hot carriers interact with all charge carriers in the system and eventually transfer their energy into phonons (heat). In my talk, I will discuss the time-dependent relaxation of plasmon-induced hot carriers including electron-electron scattering, fluorescence, and electron-phonon coupling [1] and show that the hot carrier lifetimes can exceed several picoseconds. I will also discuss recent applications of plasmon-induced hot carrier generation such as plasmon-enhanced photocatalysis, and how photocatalytic efficiencies can be enhanced by placing catalytic reactors in the nearfield of a plasmonic antenna in Antenna/Reactor geometries [2-6].



References

[1] A. Stefancu et al., “Electronic excitations at the plasmon-mol..”, Nat. Phys. 20(2024)1065

[2] L. Zhou et al., “Quantifying hot carrier and thermal ..”, Science 362(2018)69

[3] H. Robatjazi et al., “Plasmon-driven carbon–fluorine bond ..”, Nat. Catal. 3(2018)564

[4] L. Zhou et al., “Light-driven methane dry reforming ..”, Nat. Energ. 5 (2020)61

[5] M. Lou et al., “Direct H₂S Decomposition by ..”, ACS Energ. Lett. 7(2022)3666

[6] Y. Yuan et al., “Earth-abundant photocatalyst for H₂ generation ..”, Science 378(2022)889