Performance Enhancement of 2D Tin-Halide Perovskite Transistors via Molecule-Assisted Grain Boundary Passivation and Hole Doping

Tin (Sn 2+ )-based halide perovskites have garnered considerable interest for potential applications in field-effect transistors, owing to their low-cost solution processing capability and favorable hole transport properties. However, the polycrystalline nature of halide perovskite films necessitates efficient grain boundary passivation for reliable and stable device operation. Additionally, as a p-type semiconductor, controllable hole-doping is desired for modulating electrical properties. In this study, we demonstrate the dual functionality of doping the small molecule tetrafluoro-tetracyanoquinodimethane (F 4 TCNQ) into (C 6 H 5 C 2 H 4 NH 3 ) 2 SnI 4 (abbreviated as (PEA) 2 SnI 4 ) through a cost-effective solution process. This doping introduces F 4 TCNQ as both a grain boundary passivator and a charge transfer p-dopant, resulting in effective improvements in transistor performance with a 6-fold enhancement in mobility, a substantial reduction in hysteresis, an enhanced current ratio, and improved stabilities.