Tailoring tin-based perovskite crystallization via large cations and pseudo-halide anions for high mobility and high stable transistors

Tin-based perovskites, renowned for their eco-friendliness, intrinsic high hole mobility, and low effective mass, hold great potential for p-type thin-film transistors (TFTs). However, their propensity for rapid crystallization and oxidation severely limits stability and carrier mobility. Here, we strategically enhance perovskite TFT performance by incorporating 2-thiopheneethylamine thiocyanate (TEASCN) into 3D tin-based perovskites. The induction of the pseudo-halide SCN⁻ into a bilayer quasi-2D perovskite intermediate phase, combined with the strong interaction between sulfur-bearing thiophene rings (TEA⁺) and Sn-I octahedra, effectively reorients perovskite crystallization while inhibiting Sn²⁺ oxidation and reducing trap density. Consequently, TEASCN-based TFTs achieve an average hole mobility of more than 60 square centimeters per volt per second and an on/off current ratio surpassing 10⁸, standing out among state-of-the-art p-type perovskite TFTs. Furthermore, unencapsulated devices preserve 84% of their initial mobility after 30 days in an N₂ atmosphere, underscoring their remarkable stability. This work opens a straightforward path toward high-mobility and highly stable tin-based perovskite transistors.