Solution-processed tin (Sn2+)-halide perovskites can be used to create p-channel thin-film transistors (TFTs) with performance levels comparable with commercial low-temperature polysilicon technology. However, high-quality perovskite film deposition using industry-compatible production techniques remains challenging.
To address this challenge, researchers at Pohang University of Science and Technology, Korea Research Institute of Standards and Science and University of Electronic Science and Technology of China have fabricated p-channel Sn2+-halide perovskite TFTs using a thermal evaporation approach with inorganic caesium tin iodide (CsSnI3).
They used lead chloride (PbCl2) as a reaction initiator that triggers solid-state reactions of the as-evaporated perovskite compounds.
This promotes the conversion of dense and uniform perovskite films, and also modulates the intrinsically high hole density of the CsSnI3 perovskite channels.
The optimized TFTs exhibited average hole field-effect mobilities of around 33.8 cm2 V−1 s−1, on/off current ratios of around 108, and large-area fabrication uniformity. The devices also exhibited improved stability compared with solution-deposited devices.
Overall, the team reported high-performance, stable p-channel CsSnI3-based TFTs using a commercially compatible vapor-deposition approach with PbCl2 as an additive. They also demonstrated a large-scale Sn2+-halide perovskite TFT array that overcomes the technical challenges faced in the solution process. Their vapor-deposited TFTs could be used in backplanes for organic light-emitting diode displays, or in logic devices and circuits for monolithic three-dimensional integration, where low process temperatures are required.
