Dimensionality Dependent Plasticity in Halide Perovskite Artificial Synapses for Neuromorphic Computing

The hysteretic behavior of organic-inorganic halide perovskites (OHPs) are exploited for application in neuromorphic electronics. Artificial synapses with 2D and quasi-2D perovskite are demonstrated that have a bulky organic cation (phenethylammonium (PEA)) to form structures of (PEA)(2)MA(n)(-1)Pb(n)Br(3)(n)(+1). The OHP films have morphological properties that depend on their structure dimensionality (i.e., n value), and artificial synapses fabricated from them show synaptic responses such as short-term plasticity, paired-pulse facilitation, and long-term plasticity. The operation mechanism of OHP artificial synapses are also analyzed depending on the dimensionality and it is found that quasi-2D (n = 3-5) OHP artificial synapses show much longer retention than 2D and 3D OHP counterparts. The calculated energy consumption of a 2D OHP artificial synapse (approximate to 0.7 fJ per synaptic event) is comparable to that of biological synapses (1-10 fJ per synaptic event). These OHP artificial synapses may enable development of neuromorphic electronics that use very little energy.