Thermal evaporation can provide key advantages for perovskite PV fabrication over solution methods, as solvent-free steps avoid potentially hazardous and expensive solvents (e.g., dimethylformamide), which can degrade underlying layers during processing. Moreover, vacuum processing ensures a homogeneous large-area deposition on a broad variety of conductive substrates with active areas spanning from <10 mm 2 multiple pixel devices to >1010 cm PV modules, which is key for both single and multijunction applications. Here, we utilise vacuum deposition as a scalable technique for the fabrication of 10 cm 2 artificial leaves (Fig. ). Fully evaporated perovskite PV devices can be interfaced to selective Pt and Cu92In8 electrocatalysts for H2 evolution or CO2 reduction, enabling unassisted water and CO2 splitting in a tandem configuration with a BiVO4 photoanode for O2 evolution. The vacuum deposition allows us to fabricate >100 individual artificial leaves, which are used to demonstrate the modularity of PEC artificial leaves under outdoor operation. To this end, we develop a series of small-to large-scale PEC reactors approaching a m 2 size, which reveal practical insights into the effect of atmospheric conditions (temperature, pressure) and light intensity during real-world outdoor tests.