Perovskite Field-Effect Transistor Memory Employing a Large Grain Sized α-Phase Formamidinium Lead Triiodide

Halide perovskite materials have emerged as highly promising candidates for a wide range of electrical and optical devices due to their high charge carrier mobility, tunable band gaps, and facile manufacturability. However, their potential use as active channels in field-effect transistor (FET) memory devices remains underexplored, primarily due to challenges related to operational instability and the control of interfaces and crystallinity. Here, we present a significant advancement in perovskite field-effect transistor (PeFET) memory devices, utilizing large grain-sized α-phase formamidinium lead triiodide (FAPbI 3 ). The α-phase FAPbI 3 was synthesized using a black powder method with MACl and MDACl 2 additives, resulting in enhanced crystallinity and a well-defined energy bandgap. Additionally, it demonstrated excellent stability to external environmental conditions, such as high humidity (≥40 RH %) and thermal conditions (≤150 °C). Using this method, the fabricated PeFET memory devices demonstrated anticlockwise p-type switching behavior with an I ON / I OFF ratio of 1.34 ± 0.54 × 10 3 and durability over 100 continuous sweeping cycles under ambient conditions. We propose a switching mechanism that relies on the combined effects of mixed ionic-electronic conduction and charge trapping and detrapping at the interface between FAPbI 3 and SiO 2 .