A perovskite-based artificial photonic synapse with visible light modulation and ultralow current for neuromorphic computing

Photonic artificial synapses have become favorable candidates for the basic architecture of neuromorphic computing systems due to their high bandwidth, low power consumption, and low crosstalk. However, work on visible light modulated synaptic devices with biological postsynaptic currents has rarely been reported. Herein, we report a photonic synaptic device operating at ultra-low currents. It employs perovskite CsPbI2Br as the lightabsorbing layer and polymethyl methacrylate (PMMA) as the carrier blocking layer. The resulting device exhibits excellent visual cell simulation capability in the visible light range. An ultra-low post-synaptic current of picoampere level can be achieved with visible-light modulation, which is much lower than that of normal photonic synaptic devices. It also exhibited superior memory retention of over 1000 s and low power consumption of 4.25 pJ. Furthermore, the sensory memory (SM), short-term memory (STM), and long-term memory (LTM) are successfully simulated in visible light. An artificial neural network-based neuromorphic computing was also simulated, with the recognition accuracy of MNIST data reaching 95.99% for small digits and 95.34% for large digits. Overall, our work provides promising strategies for low-current photonic neuromorphic applications.