Ionic liquid additive induced holistic trap-passivation for enhanced charge transport in lead-halide perovskite-based transistors

Incorporating ionic liquid additives into perovskite-based electronic devices has been considerably demonstrated to improve device performance and stability via synergistic passivation effects. However, the advantages and understanding of ionic additives in perovskite field-effect transistors (FETs) have been explored far less. Herein, holistic trap-passivation is reported in a poly(3-hexylthiophene)-functionalized electrolyte-gated perovskite FETs with a solid-state ionic liquid (ss-IL) additive. The optimized ss-IL-incorporated methylammonium lead iodide (MAPbI₃/ss-IL) FETs exhibited remarkable hole mobility of over 30 cm² V⁻¹ s⁻¹ at an operating voltage of –1.5 V, attributed to suppressed lead/iodine vacancies and related traps and exhibiting excellent operational stability under ambient conditions with recoverable complex hysteresis behavior. These results demonstrate the promising synergistic impacts of the proposed trap engineering and provide a fundamental understanding of charge transport physics in doped perovskite semiconductors, essential for advancing their application as transistor-based devices.