Researchers at the Karlsruhe Institute of Technology (KIT) have developed a prototype for fully scalable all-perovskite tandem solar modules. These modules have an efficiency of up to 19.1 percent with an aperture area of 12.25 square centimeters. This result, the first of its kind reported worldwide, was made possible by improving efficiency with optimized light paths, high-throughput laser scribing, and the use of established industrial coating methods. The researchers present their results in the journal Nature Energy. (DOI: 10.1038/s41560-022-01059-w)