Recent progress in three-terminal artificial synapses based on 2D materials:from mechanisms to applications

Synapses are essential for the transmission of neural signals.Synaptic plasticity allows for changes in synaptic strength,enabling the brain to learn from experience.With the rapid development of neuromorphic electronics,tremendous efforts have been devoted to designing and fabricating electronic devices that can mimic synapse operating modes.This growing interest in the field will provide unprecedented opportunities for new hardware architectures for artificial intelligence.In this review,we focus on research of three-terminal artificial synapses based on two-dimensional(2D)materials regulated by electrical,optical and mechanical stimulation.In addition,we systematically summarize artificial synapse applications in various sensory systems,including bioplastic bionics,logical transformation,associative learning,image recognition,and multimodal pattern recognition.Finally,the current challenges and future perspectives involving integration,power consumption and functionality are outlined.

Low-dimensional optoelectronic synaptic devices for neuromorphic vision sensors

Neuromorphic systems represent a promising avenue for the development of the next generation of artificial intelligence hardware.Machine vision,one of the cores in artificial intelligence,requires system-level support with low power consumption,low latency,and parallel computing.Neuromorphic vision sensors provide an efficient solution for machine vision by simulating the structure and function of the biological retina.Optoelectronic synapses,which use light as the main means to achieve the dual functions of photosensitivity and synapse,are the basic units of the neuromorphic vision sensor.Therefore,it is necessary to develop various optoelectronic synaptic devices to expand the application scenarios of neuromorphic vision systems.This review compares the structure and function for both biological and artificial retina systems,and introduces various optoelectronic synaptic devices based on low-dimensional materials and working mechanisms.In addition,advanced applications of optoelectronic synapses as neuromorphic vision sensors are comprehensively summarized.Finally,the challenges and prospects in this field are briefly discussed.

Self-sensing intelligent microrobots for noninvasive and wireless monitoring systems

Microrobots have garnered tremendous attention due to their small size,flexible movement,and potential for various in situ treatments.However,functional modification of microrobots has become crucial for their interaction with the environment,except for precise motion control.Here,a novel artificial intelligence(AI)microrobot is designed that can respond to changes in the external environment without an onboard energy supply and transmit signals wirelessly in real time.The AI microrobot can cooperate with external electromagnetic imaging equipment and enhance the local radiofrequency(RF)magnetic field to achieve a large penetration sensing depth and a high spatial resolution.The working ranges are determined by the structure of the sensor circuit,and the corresponding enhancement effect can be modulated by the conductivity and permittivity of the surrounding environment,reaching~560 times at most.Under the control of an external magnetic field,the magnetic tail can actuate the microrobotic agent to move accurately,with great potential to realize in situ monitoring in different places in the human body,almost noninvasively,especially around potential diseases,which is of great significance for early disease discovery and accurate diagnosis.In addition,the compatible fabrication process can produce swarms of functional microrobots.The findings highlight the feasibility of the self-sensing AI microrobots for the development of in situ diagnosis or even treatment according to sensing signals.