Dual-Phase All-Inorganic Cesium Halide Perovskites for Conducting-Bridge Memory-Based Artificial Synapses

Neuromorphic computing, which mimics biological neural networks, can overcome the high-power and large-throughput problems of current von Neumann computing. Two-terminal memristors are regarded as promising candidates for artificial synapses, which are the fundamental functional units of neuromorphic computing systems. All-inorganic CsPbI3 perovskite-based memristors are feasible to use in resistive switching memory and artificial synapses due to their fast ion migration. However, the ideal perovskite phase alpha-CsPbI3 is structurally unstable at ambient temperature and rapidly degrades to a non-perovskite delta-CsPbI3 phase. Here, dual-phase (Cs3Bi2I9)(0.4)-(CsPbI3)(0.6) is successfully fabricated to achieve improved air stability and surface morphology compared to each single phase. Notably, the Ag/polymethylmethacrylate/(Cs3Bi2I9)(0.4)-(CsPbI3)(0.6)/Pt device exhibits non-volatile memory functions with an endurance of approximate to 10(3) cycles and retention of approximate to 10(4) s with low operation voltages. Moreover, the device successfully emulates synaptic behavior such as long-term potentiation/depression and spike timing/width-dependent plasticity. This study will contribute to improving the structural and mechanical stability of all-inorganic halide perovskites (IHPs) via the formation of dual phase. In addition, it proves the great potential of IHPs for use in low-power non-volatile memory devices and electronic synapses.