E-Synapse Based on Lead-Free Organic Halide Perovskite (CH₃NH₃)₃Sb₂Cl₉ for Neuromorphic Computing

Memristors based on organic-inorganic halide perovskite have received intensive attention because of its solution-processability and defect-tolerant characteristics. But the lead element in perovskite is inevitably harmful to human body and environment. Herein, we report an e-synapse based on lead-free organic halide perovskite (CH ₃ NH ₃ ) ₃ Sb ₂ Cl ₉ (MA ₃ Sb ₂ Cl ₉ ), which exhibits excellent mimic of biological synaptic characteristics, such as excitatory postsynaptic currents (EPSCs), inhibitory postsynaptic currents (IPSCs), and paired-pulse facilitation (PPF). Furthermore, the synaptic weight of the e-synapse is found to be dependent on the frequency of pulse stimulation. The charge conduction mechanism of the e-synapse is proposed based on the in-depth investigation of the electrical characteristics of the devices. This work demonstrates that lead-free organic perovskite MA ₃ Sb ₂ Cl ₉ provide a new perspective on engineering e-synapses for neuromorphic computing and have a great potential for environment-friendly artificial intelligence applications.