Surface group-governed charge storage in carbon dots for a visual memristor

Visual memristors, which integrate resistive switching with optical feedback, are attracting growing interest for neuromorphic computing, nonvolatile storage, and human-machine interfaces. By directly coupling electrical states with optical outputs, such devices enable both data processing and intuitive visualization, providing new opportunities for interactive and multifunctional systems. Here, we innovatively demonstrate a carbon dot (CD)-based visual memristor that combines reliable resistive switching with tunable electroluminescence. The device exhibits stable storage, reproducible hysteresis loops, and multilevel conductance control, while its emission spectra systematically evolve with resistive states, enabling "visible" memory and computation. This dual-mode behavior bridges the electrical and optical domains, closely resembling synaptic plasticity and supporting artificial neuromorphic functions. Benefiting from the unique properties of CDs, including strong luminescence, abundant surface functionalities, and facile solution processing, the proposed device represents a new platform for multifunctional optoelectronic systems. These results open pathways toward next-generation neuromorphic optoelectronics that unify perception, memory, and processing.