Two-terminal self-rectifying optoelectronic synaptic devices with largest-dynamic-range updates

Two-terminal optoelectronic synaptic devices have attracted increasing attention owing to their simplicity of structures, which facilitate the device integration in neuromorphic computing systems. However, synaptic-weight updates and self-rectifying properties in two-terminal optoelectronic synaptic devices are inferior. Here, we fabricate two-terminal optoelectronic synaptic devices in accordance with the hybrid structure of optically active layers MAPbI3 and electron transport layers (ETLs) SnO2 in an n-i-p planar system, where MAPbI3 and SnO2 are used for generating and trapping carriers, respectively. Synaptic functionalities such as excitatory post-synaptic current (EPSC), paired-pulse facilitation (PPF), spike-number dependent plasticity (SNDP), and spike-rate dependent plasticity (SRDP) are all successfully mimicked without external bias. These synaptic devices possess self-rectifying properties with a highest ratio of ∼0.3 × 103 and their synaptic weight exhibits largest-dynamic-range updates of 14.3 within 14 seconds among the reported two-terminal optoelectronic synaptic devices. Furthermore, the spike-number tunability of EPSC in the synaptic devices leads to the realization of straight running of agrimotor driverless technology. Results dramatically promote the development of two-terminal optoelectronic synaptic devices in neuromorphic computing.