Flexible Threshold Switching Based on CsCu2I3 with Low Threshold Voltage and High Air Stability

Halide perovskites featuring remarkable optoelectronic properties hold great potential for threshold switching devices (TSDs) that are of primary importance to next-generation memristors and neuromorphic computers. However, such devices are still in their infancy due to the unsolved challenges of high threshold voltage, poor stability, and lead-containing features. Herein, a unipolar TSD based on an all-inorganic halide perovskite of CsCu2I3 is demonstrated, exhibiting the fascinating attributes of a low threshold voltage of 0.54 V, a high ON/OFF ratio of 10(4), robust air stability over 70 days, a steep switching slope of 6.2 mV center dot decade(-1), and lead-free composition. Moreover, the threshold voltage can be further reduced to 0.23 V using UV illumination to reduce the barrier of iodide ion migration. The multilevel threshold switching behavior can be realized through the modulation of either the compliance current or the scan rate. The TSD with mechanical compliance and transparency is also demonstrated. This work enriches TSDs with expanded perovskite materials, boosting the related applications of this emerging class of device families.

Automated summary

Halide perovskites are promising materials for next-generation memristors and neuromorphic computers. In this study, a unipolar threshold switching device (TSD) based on all-inorganic CsCu2I3 perovskite is demonstrated, exhibiting low threshold voltage, high ON/OFF ratio, robust stability, and lead-free composition. The performance can be further improved through UV illumination.