1D Hexagonal HC(NH2)2PbI3 for Multilevel Resistive Switching Nonvolatile Memory

Organic-inorganic halide perovskite is regarded as one of the potential candidates for next generation resistive switching memory (memristor) material because of fast, millivolt-scale switching, multilevel capability, and high On/Off ratio. Here, resistive switching property of HC(NH2)(2)PbI3 (FAPbI(3)) depending on structural phase is reported. It is found that 1D hexagonal FAPbI(3) (delta-FAPbI(3)), formed at relatively low temperature, is active in memristor, while 3D trigonal FAPbI3 (alpha-FAPbI(3)), formed at temperature higher than 150 degrees C, is inactive. Failure of switching from low resistance state to high resistance state is found for alpha-FAPbI(3), while delta-FAPbI(3) shows stable switching behavior. Density functional calculation reveals that iodine cluster in isotropic 3D alpha-FAPbI(3) is so stable after forming filament that the filament is hard to be ruptured at off state. However, for anisotropic delta-FAPbI(3), iodine cluster is not stable and migration barrier is much lower for c-axis (0.48 eV) than for ab-plane (0.9 eV), which is beneficial for switching. The memristor devices based on delta-FAPbI(3) demonstrate endurance up to 1200 cycles with On/Off ratio (>10(5)), retention time up to 3000 s, multilevel storage capacity, and working even at 80 degrees C.