Flexible Solution Processable Black Phosphorus Based Optoelectronic Memristive Synapse for Neuromorphic Computing and Artificial Visual Perception Applications.

Being renowned for operating with visible light pulses and electrical signals, optoelectronic memristive synaptic devices have excellent potential for neuromorphic computing systems and artificial visual information processing. Here, we present a flexible back-end-of-line compatible optoelectronic memristor based on solution-processable black phosphorus/HfOx bilayer with excellent synaptic features, towards biomimetic retinas. The device shows highly stable synaptic features such as long-term potentiation (LTP) and long-term depression (LTD) for repetitive 1000 epochs, having 400 conductance pulses, each. The device presents advanced synaptic features in terms of long-term memory (LTM)/short term memory (STM), as well as learning-forgetting-relearning when visible light was induced on it. These advanced synaptic features can improve the information processing abilities for neuromorphic applications. Interestingly, the STM can be converted into LTM by adjusting the intensity of light and illumination time. Using the light induced characteristics of the device, a 6×6 synaptic array was developed to exhibit possible use in artificial visual perception. Moreover, the devices were flexed using a Silicon back-etching process. The resulting flexible devices demonstrate stable synaptic features when bent down to 1 cm radius. These multifunctional features in a single memristive cell make it highly suitable for optoelectronic memory storage, neuromorphic computing, and artificial visual perception applications.