Dynamic Charge Gradients from Interfacial Electron Transfer Enable Self-Powered Gate-Controlled All-Metal-Nanoparticle Neuromorphic Systems

Harvesting electricity from ambient moisture represents a transformative approach to power generation, a process traditionally ascribed solely to ion or proton diffusion. Here, we report a moisture-energy-harvesting mechanism that originates from interfacial electron transfer in a ligand-decorated metal nanoparticle film. Partially covering the film creates an asymmetric humidity gradient that triggers unbalanced electron transfer from adsorbed water to the metal nanoparticle core. This establishes a persistent dynamic charge separation and concentration gradient along the film that is sustained by continuous water evaporation from its exposed side, as supported by multiscale simulations. With this mechanism, we demonstrate that the electricity generated by these nanoparticle devices can not only power common microelectronic devices but also be directly integrated with a nanoparticle synaptic transistor to achieve a self-powered gate-controlled all-metal-nanoparticle neuromorphic system.