Enhancing Voltage Tolerance of CsFA Perovskite‐Based Rectifying Diodes Through Ionic Liquid Incorporation

Abstract Metal halide perovskites have gained significant attention owing to their remarkable semiconductor properties and superior optoelectronic characteristics. In this study, low‐voltage‐driven rectifying diodes are developed based on CsFAPbI ₃ and their voltage tolerance is enhanced by incorporating ionic liquids. The fabricated FTO/TiO ₂ /CsFAPbI ₃ /Ag diode exhibits a low turn‐on voltage of 181 mV and a high rectifier ratio of 2.8 × 10 ⁴ under 400 mV voltage application, which are superior or comparable to those of reported solution processable diodes. However, its voltage tolerance is limited; the hysteresis and the leakage current increase during voltage sweep cycling. By incorporating an ionic liquid, 1‐hexyl‐3‐methylimidazolium chloride, into CsFAPbI ₃ , the diodes voltage tolerance improves, maintaining the excellent performances. Alternating current (AC) impedance measurements suggeste that this improvement is attributable to reduced ion migration. AC to direct current (DC) conversion simulation studies indicated that the CsFAPbI ₃ ‐based diodes achieve an output voltage of 227 mV under a 400 mV, 125 kHz AC input and 84 mV under a 400 mV, 13.56 MHz input, highlighting their potential for AC–DC conversion in low‐power applications. In addition, the improved voltage tolerance of the CsFAPbI ₃ also shows photodetector devices, underlining the vast potential of ionic liquid‐incorporated metal halide perovskite‐based optoelectronic devices.