Large metal halide perovskite crystals for field-effect transistor applications

The material 2-phenylethylammonium tin iodide perovskite (C₆H₅C₂H₄NH₃)₂SnI₄ [abbreviated as (PEA)₂SnI₄] has shown promising performance as a polycrystalline semiconductor for field-effect transistors (FETs). However, grain boundaries and structural disorder in polycrystalline films limit performance, and so the fundamental upper bounds of the material are yet to be studied. Here, we prepared large crystals of (PEA)₂SnI₄ for FETs and demonstrated carrier mobilities of 40 cm² V^-1 s^-1 or higher, although with a low fabrication yield (< 1%). Our crystal FETs were very stable when stored in air and when operated under a bias in vacuum. The FET characteristics were superior to those of reported FETs based on polycrystalline perovskite films, and these results contribute to a better understanding of basic carrier transport mechanisms in hybrid perovskite materials.