Potentiation and depression phosphorescent plasticity of multiconfined carbon dot for all-optical neuromorphic imaging

Abstract

All-optical artificial synapses capable of both excitatory and inhibitory plasticity are highly desirable in next-generation neuromorphic technologies, owing to their optical signal input and output. Here we report a bidirectional all-optical synapse with both potentiation and depression plasticity, utilizing a persistent phosphorescent elastomer constructed from multiconfined carbon dots with long afterglow. The synapse exhibits excitatory optical plasticity, with the output intensity progressively enhanced by increasing irradiation intensity, duration, and pulse count at constant temperature, originating from excited electron superposition. Conversely, inhibitory plasticity is realized via temperature-modulated phosphorescence, where elevated temperature accelerates nonradiative vibrational decay, leading to suppressed phosphorescence intensity. Notably, this synapse converts invisible ultraviolet light into visible afterglow, enabling the visualization of irradiation intensity and temporal plasticity. Neuromorphic imaging simulations demonstrate recognition accuracy of 86% in intensity mode and 64% in pulse mode in handwritten digit recognition. These results offer a promising platform for the development of emerging all-optical neuromorphic imaging systems.