High-performance tin-based perovskite field-effect transistors realized by improving film morphology via bifunctional...

Tin-based perovskites have emerged as promising semiconductor materials for high-performance field-effect transistors (FETs). However, poor film quality of tin-based perovskites seriously impedes carrier transport and degrades operational stability of the FETs. In this study, we propose a bifunctional additive strategy employing 4-fluorophenethylamine acetate (FPEAAc) to regulate the crystallization of Sn-based perovskites, resulting in preferentially oriented, fully covered and large-grained perovskite films. The FPEA⁺ cations induced the templating growth of perovskite octahedron, while Ac^- anions retard the crystallization growth to promote uniform films. To further enhance grain size while maintaining pinhole-free morphology, propylammonium acetate (PAAc) additive is introduced as an auxiliary additive to further delay crystal growth. The optimized FETs demonstrate a high hole mobility of ∼40 cm² V^-1 s^-1 along with excellent operational stability. This work establishes a co-additive strategy that precisely regulates tin-based perovskite crystallization through templated growth coupled with retarded crystallization, offering novel insights into regulating the film growth of Sn-based perovskites, and thereby advancing the development of high-performance perovskite FETs.