Analog Memristor of Lead‐Free Cs 4 CuSb 2 Cl 12 Layered Double Perovskite Nanocrystals as Solid‐State Electronic Synapse for Neuromorphic Computing

Brain-inspired artificial neural networks and neuromorphic computing are taking space to a new height based on solid-state memristor devices. Despite considerable progress already made, the use of lead-free double perovskite materials with direct bandgap can be recognized as a significant paradigm shift in this field. Here, growth, thin film deposition, and analog electroforming-free resistive switching property along with promising artificial synaptic and neural activities of lead-free layered cesium copper antimony chloride (Cs4CuSb2Cl12 or CCAC) double perovskite nanocrystals are reported. Optical and structural characterizations of CCAC microcrystals (MCs) and nanocrystals (NCs) confirm the growth, the existence of direct bandgap, and <111> oriented monoclinic crystal phase of space group C2/m. Interestingly, both the MCs and NCs display an almost equal bandgap of 1.1 eV in thin film even though they have higher bandgaps of 1.3 and 2.2 eV in dispersion, respectively. However, devices of NC thin film exhibit superior memristor behavior along with emulation of various synaptic and neural activities due to having less number of defects. Finally, the analog modulation of synaptic weight using CCAC memristor, in terms of postsynaptic currents, during potentiation and depression represents a significant achievement toward hardware implementation of neural networks and neuromorphic computing.