Charge-transport enhancement in environmentally stable hysteresis-free perovskite transistors with hybrid channel

The immense development of metal halide perovskite (MHP) thin-film transistors (TFTs) in recent years has enabled insightful understanding of their device fabrication and optimization. The excellent mechanical flexibility, low-temperature solution processability and moderately low cost of MHPs provide considerable advantages in probing their operational and environmental stability. Herein, a novel synergistic engineering approach using a solid-state ionic liquid 1-dodecyl-3-methylimidazolium hexafluorophosphate and poly(3-hexylthiophene-2,5-diyl) (P3HT) polymer additives is incorporated into the formamidinium lead triiodide (FAPbI₃) perovskite semiconducting layer for high-performance and air-stable hybrid perovskite TFTs. Our optimized hybrid perovskite TFTs measured an enhanced hole mobility of over 2 cm² V⁻¹ s⁻¹ with a reduced hysteresis incorporating ionic liquid additive. Furthermore, the hybrid FAPbI₃-P3HT TFTs exhibited hysteresis-free transfer characteristics, achieving a hole mobility of over 4 cm² V⁻¹ s⁻¹ under ambient conditions. This improvement is attributed to suppression of lead-related defects and traps through molecular interactions, iodide vacancy passivation through p-doping effect of oxygen and regulated crystallization process of perovskite components. Moreover, the corresponding devices showed no degradation in the transfer characteristics after 432 hr under ambient conditions. Our results and approach could pioneer the realization of low-power and environmentally stable perovskite transistor-based electronics.