| 论文摘要： |
Halide ion migration in 2D perovskite heterostructures has long hindered the realization of their extraordinary optoelectronic properties, resulting in current-voltage hysteresis and reduced device stability. Here, it demonstrated that tin (Sn) substitution at the perovskite B-site effectively stabilizes ultrathin 2D halide perovskite epitaxial heterostructures by suppressing halide ion migration and boosting charge transport. Density functional theory (DFT) calculations indicate that Sn2+ incorporation raises the energy barrier for halide migration, optimizes band alignment, and lowers the effective hole mass, collectively mitigating ionic instability and promoting efficient interfacial charge transfer. As a result, field-effect transistors (FETs) based on (PEA)2Pb0.7Sn0.3Br4-(PEA)2PbI4 (PEA = phenylethylamine) heterojunctions achieve hysteresis-free operation, a subthreshold swing of 813 mV dec-1, an on/off ratio of 2.52 x 106 and a hole mobility of 8.41 cm2 V-1 s-1, positioning them among the high-mobility p-type 2D perovskite thin-film FETs reported to date. These findings advance a robust strategy for stabilizing 2D perovskite heterostructures and open new pathways for integrating them into next-generation electronic and photonic systems. |
