Retina-Inspired Two-Terminal Optoelectronic Neuromorphic Devices with Light-Tunable Short-Term Plasticity for Self-Adjusting Sensing

In current optical imaging devices, complex peripheral circuits are required to obtain clear and true images, which leads to limited power and area efficiency. Inspired by the visual processing in retina, an optoelectronic neuromorphic device with short-term plasticity (STP) can realize self-adjustment of the visual system to real time in response to the external stimuli, including light controlled short-term facilitation (STF) and short-term depression (STD). Herein, an optoelectronic synaptic device based on a simple Au/ZnS/Pt structure is found to show both synaptic STD and STF under light stimulation. STD originates from photoexcited carriers trapped by defects in the ZnS film, whereas STF results from photocurrent rising due to trap filling via previous electrical stimulation. Moreover, the STP of the device exhibits excellent stability and repeatability. In addition, this optoelectronic device can be used to adjust the sharpness of the view according to different brightness levels through STD and STF. The realization of self-adjustment through STP of the emerging optoelectronic neuromorphic device may pave the way for bionic systems facing complex environments.