Narrow-band-gap Sn-Pb perovskites have emerged as one of the most promising solution-processed near-infrared (NIR) light-detection technologies, with the key figure-of-merit parameters already rivaling those of commercial inorganic devices, but maximizing the cost advantage of solution-processed optoelectronic devices depends on the ability to fast-speed production. However, weak surface wettability to perovskite inks and evaporation-induced dewetting dynamics have limited the solution printing of uniform and compact perovskite films at a high speed. Here, we report a universal and effective methodology for fast printing of high-quality Sn-Pb mixed perovskite films at an unprecedented speed of 90 m h-1 by altering the wetting and dewetting dynamics of perovskite inks with the underlying substrate. A line-structured SU-8 pattern surface to trigger spontaneous ink spreading and fight ink shrinkage is designed to achieve complete wetting with a near-zero contact angle and a uniform dragged-out liquid film. The high-speed printed Sn-Pb perovskite films have both large perovskite grains (>100 μm) and excellent optoelectronic properties, yielding highly efficient self-driven NIR photodetectors with a large voltage responsivity over 4 orders of magnitude. Finally, the potential application of the self-driven NIR photodetector in health monitoring is demonstrated. The fast printing methodology provides a new possibility to extend the manufacturing of perovskite optoelectronic devices to industrial production lines.
Keywords: Sn−Pb mixed perovskite; fast deposition; narrow-band-gap perovskite; near-infrared photodetectors; solution printing.