Flexible and Scalable 2D/3D Tin‐Based Perovskite Photodetectors via Inkjet Printing

ABSTRACT

This study investigates the scalable development of lead‐free 2D/3D metal halide perovskites for advanced optoelectronic applications via the precise deployment of inkjet printing. Specifically, (PEA _0.5 BA _0.5 ) ₂ FA ₉ Sn ₁₀ I ₃₁  films were successfully printed onto both rigid glass and flexible polyethylene terephthalate (PET) substrates prepatterned with indium tin oxide (ITO) interdigitated electrodes. To address the persistent challenge of chemical instability and oxidation inherent to tin‐based perovskites, a novel synthesis of high‐purity SnI ₂  precursor was combined with a robust dual‐layer encapsulation strategy comprising sequential polymethyl methacrylate (PMMA) and epoxy resin layers. Electro‐optical evaluations conducted under continuous‐wave (DC) illumination revealed a pronounced photoconductive gain mechanism with a high responsivity exceeding 50 A/W under low incident powers (at 5–10 V bias), accompanied by persistent photoconductivity governed by carrier trapping/detrapping dynamics. Conversely, modulated (AC) light characterization successfully bypassed these slower trapping pathways, enabling high‐frequency device operation with a cut‐off frequency of 400 kHz, at the expense of a lower responsivity (0.1–0.2 A/W). Crucially, long‐term operational testing spanning 30 days revealed no structural or performance degradation with responsivities as high as 50 A/W. These findings provide critical insights into the practical fabrication of sustainable, low‐cost, and high‐performance lead‐free perovskite photodetectors compatible with next‐generation flexible and wearable electronics.