Enhanced Surface Fields Driven by Fano Resonances in Silver Nanocube Dimers for Efficient Hot Electron Generation

Plasmonic nanoparticles (PNPs) have emerged as promising catalysts for future energy generation technologies due to their ability to induce high-energy hot electron generation through nonradiative plasmon decay. This phenomenon is particularly pronounced by the huge field gradients at plasmonic hot spots and the excitation of dark plasmon modes from Fano interferences. Despite the growing interest in the field, the literature exploring Fano resonances for plasmon-based photocatalysts remains sparse. In this study, we investigate the potential for hot carrier generation of plasmonic systems using silver nanocube (AgNC) dimers with varying rounding degrees as model platforms, known to exhibit Fano-like resonances. The simulations were conducted using the boundary element method (BEM) through the MNPBEM17 toolbox. Additionally, a coupled oscillator model was employed to obtain supplementary evidence regarding the presence and the origin of Fano resonances in these systems. Our computational findings provide a direct correlation between Fano resonances and hot carrier generation, elucidated through the observed near-field enhancement at the particle surface within the Fano spectral window. Notably, our results indicate an increased effect for Fano resonances involving higher-order plasmon modes. To the best of our knowledge, this work represents the first comprehensive study of this kind. Overall, our work provides a better understanding of the interplay between Fano resonances and near-field effects in hot electron generation, thereby contributing to the rational design of highly efficient energy conversion technologies.