Two-Dimensional Dion–Jacobson-Phase Tin Perovskite Using Heteroaromatic Diammonium Cations for Phototransistors

Two-dimensional (2D) Dion-Jacobson (DJ)-phase tin-based perovskites show great promise for field-effect transistors (FETs) due to their excellent charge transport properties and structural stability. However, the limited variety of diammonium cations has hindered their further development in electronic devices. In this work, we synthesized a 2D DJ-phase tin perovskite, 3AMPYSnI₄, using asymmetric diammonium cation 3-(aminomethyl)pyridinium (3AMPY²⁺). Single-crystal analysis confirms a typical DJ-phase structure with zigzag-stacked inorganic layers. The 3AMPYSnI₄ thin film is polycrystalline without a preferred orientation, exhibiting a high absorption coefficient (∼10⁵ cm^-1) and p-type nature. The 3AMPYSnI₄ FETs show typical p-type transport behavior with a maximum hole mobility of 3.12 × 10^-3 cm² V^-1 s^-1 and demonstrate good operational stability. Moreover, under 460 nm illumination, the device achieves a responsivity of 1.20 × 10² A/W and a specific detectivity of 1.46 × 10¹² Jones, highlighting its potential for visible-light detection. This study provides a new direction for developing 2D DJ-phase perovskites and their applications in high-performance optoelectronic devices.