Photoinduced Dissolution of Ag Nanorods on Au Substrates and Its Inhibition

Silver nanostructures are widely employed in plasmonics owing to their low optical losses and strong field confinement. However, their intrinsic instability is often implicitly accepted and addressed through protective strategies, rather than being systematically examined in device-relevant configurations. Here, we report on a previously unrecognized photoinduced dissolution of individual Ag nanorods supported on Au substrates. Using real-time dark-field scattering spectroscopy combined with correlative scanning electron microscopy, we directly visualize the dynamic and spatially heterogeneous morphological evolution of Ag nanorods under continuous illumination. We show that the dissolution behavior strongly depends on light exposure and the nature of the supporting substrate. By deliberately modifying the interfacial environment, we demonstrate three effective strategies that suppress the dissolution process and preserve the structural integrity of Ag nanorods under illumination. These findings move beyond treating Ag instability as an inherent material limitation and instead establish an experimental basis for understanding and controlling the optical stability of substrate-supported Ag nanostructures.