Ambipolar transport in two-dimensional Sn-based perovskite field-effect transistors using an aliphatic polymer-assisted method

Abstract

Two-dimensional layered Sn-based perovskites with superior carrier mobility and excellent compatibility with horizontal charge transport in field-effect transistors are promising channel materials. However, ambipolar characteristics cannot be achieved and p-type accumulation–depletion mode is generally observed in phenethylammonium tin iodide ((PEA)₂SnI₄) transistors in ambient air. Herein, aliphatic polymers poly(ethylene oxide) (PEO), poly(vinyl alcohol) (PVA), and poly(methyl methacrylate) (PMMA), which have different oxygen-containing functional groups and can interact differently with (PEA)₂SnI₄, are employed as additives to modulate the optoelectronic properties of the perovskite thin films and control the operation mode of the polymer-assisted (PEA)₂SnI₄ field-effect transistors. PEO effectively eliminates hole depletion and achieves ambipolar transport in the transistors because it can inhibit the oxidation of Sn²⁺ and passivate the related electron traps via the Sn–O coordination interactions between the ether group in PEO and the Sn²⁺ ion in (PEA)₂SnI₄, whereas PVA and PMMA only improve the device performance. Our work provides a valuable strategy for the suppression of the oxidation and passivation of defects in Sn-based perovskites by choosing a suitable polymer additive and opens up a path to realize ambipolar field-effect Sn-based perovskite transistors on low-cost and commercially available polymer dielectrics for future applications in solution-based flexible optoelectronics.