High-Speed Printing of Narrow-Band-Gap Sn-Pb Perovskite Layers toward Cost-Effective Manufacturing of Optoelectronic Devices

Narrow-band-gapSn-Pb perovskites have emerged as one ofthe most promising solution-processed near-infrared (NIR) light-detectiontechnologies, with the key figure-of-merit parameters already rivalingthose of commercial inorganic devices, but maximizing the cost advantageof solution-processed optoelectronic devices depends on the abilityto fast-speed production. However, weak surface wettability to perovskiteinks and evaporation-induced dewetting dynamics have limited the solutionprinting of uniform and compact perovskite films at a high speed.Here, we report a universal and effective methodology for fast printingof high-quality Sn-Pb mixed perovskite films at an unprecedentedspeed of 90 m h(-1) by altering the wetting and dewettingdynamics of perovskite inks with the underlying substrate. A line-structuredSU-8 pattern surface to trigger spontaneous ink spreading and fightink shrinkage is designed to achieve complete wetting with a near-zerocontact angle and a uniform dragged-out liquid film. The high-speedprinted Sn-Pb perovskite films have both large perovskite grains(>100 & mu;m) and excellent optoelectronic properties, yieldinghighly efficient self-driven NIR photodetectors with a large voltageresponsivity over 4 orders of magnitude. Finally, the potential applicationof the self-driven NIR photodetector in health monitoring is demonstrated.The fast printing methodology provides a new possibility to extendthe manufacturing of perovskite optoelectronic devices to industrialproduction lines.