Imaging silver-nanoparticle-decoration-boosted charge separation and transport in InP by scanning ultrafast electron microscopy

Indium phosphide (InP) is a promising photocatalyst, yet its performance is often limited by fast carrier recombination and inefficient charge transport. Deng \emph{et al}. use scanning ultrafast electron microscopy (SUEM) to directly visualize photoexcited carrier dynamics on femtosecond-nanometer scales at the InP surface decorated with silver nanoparticles. SUEM reveals that Ag nanoparticles remarkably enhance light absorption via localized surface plasmon resonance, leading to stronger charge separation, suppressed recombination, and a pronounced early-time boost in lateral carrier transport. In contrast, a continuous Ag film improves separation through a Schottky junction but shows limited diffusion, underscoring the unique role of plasmonic nanoparticles.