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

Halide perovskites featuring remarkable optoelec-tronic 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 CsCu(2)I(3 )is demonstrated, exhibiting the fascinating attributes of a low threshold voltage of 0.54 V, a high ON/OFF ratio of 104, robust air stability over 70 days, a steep switching slope of 6.2 mV & BULL; 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

This study demonstrated a unipolar TSD based on all-inorganic CsCu2I3 halide perovskite with features of low threshold voltage, high ON/OFF ratio, long-term stability, steep switching slope, and lead-free composition, while the threshold voltage can be further reduced through UV illumination.