Ion Migration Control in Lead‐Free Halide Perovskite Transistors for Logic and Neuromorphic Circuits

Lead-free halide perovskite field-effect transistors (PeFETs) are emerging as promising platforms for logic and neuromorphic circuits in flexible electronics, owing to their superior charge transport, facile solution processing, and mechanical compatibility. In contrast to lead-based counterparts, tin (Sn)-based perovskites exhibit higher vacancy migration barriers that suppress undesirable levels of ion migration, enabling more stable logic operation. However, a moderate level of ion migration persists and may be exploited for neuromorphic behavior if properly managed, highlighting the paradoxical role of ionic motion as both a liability and an asset. External inputs such as electric fields, temperature, and optical stimuli offer additional means to modulate this multifunctionality. Despite this promise, robust and scalable integration into functional circuits across diverse substrates and device architectures remains a crucial challenge. However, recent advances in wafer-scale arrays provide a promising foundation for the future realization of scalable, large-area, and wearable applications. This review presents a sustainability-driven roadmap for CMOS-compatible, lead-free Sn-based PeFETs, outlining strategies to integrate reliable logic performance with adaptive neuromorphic operation. These developments highlight the multifunctional potential of Sn-based halide perovskites and lay the groundwork for environmentally responsible, next-generation intelligent electronics.