The efficiencies of small-pixel perovskite photovoltaics have increased to above 24%, while most reported fabrication methods cannot be transferred to scalable manufacturing process. Here, we report a method of fast blading large-area perovskite films at an unprecedented speed of 99 mm/s under ambient conditions by tailoring solvent coordination capability. Combing volatile noncoordinating solvents to Pb2+ and low-volatile, coordinating solvents achieves both fast drying and large perovskite grains at room temperature. The reproducible fabrication yields a certified module efficiency of 16.4%, with an aperture area of 63.7 cm2. This method can be applied for various perovskite compositions. The perovskite modules also show a small temperature coefficient of −0.13%/°C and nearly fully recoverable efficiency after 58 cycles of shading, much better than commercial silicon and thin-film solar modules.

State-of-the-art, high-performance perovskite solar cells (PSCs) contain a large amount of iodine to realize smaller bandgaps. However, the presence of numerous iodine vacancies at the surface of the film formed by their evaporation during the thermal annealing process has been broadly shown to induce deep-level defects, incur nonradiative charge recombination, and induce photocurrent hysteresis, all of which limit the efficiency and stability of PSCs. In this work, modifying the defective surface of perovskite films with cadmium iodide (CdI 2 ) effectively reduces the degree of surface iodine deficiency and stabilizes iodine ions via the formation of strong Cd−I ionic bonds. This largely reduces the interfacial charge recombination loss, yielding a high efficiency of 21.9% for blade-coated PSCs with an open-circuit voltage of 1.20 V, corresponding to a record small voltage deficit of 0.31 V. The CdI 2 surface treatment also improves the operational stability of the PSCs, retaining 92% efficiency after constant illumination at 1 sun intensity for 1000 h. This work provides a promising strategy to optimize the surface/interface optoelectronic properties of perovskites for more efficient and stable solar cells and other optoelectronic devices.

Perovskite materials are good candidates for flexible photovoltaic applications due to their strong absorption and low-temperature processing, but efficient flexible perovskite modules have not been realized yet. Here, we demonstrate a record efficiency flexible perovskite solar module by blade coating high-quality perovskite films on flexible Corning® Willow® Glass using additive engineering. Ammonium chloride (NH 4 Cl) is added into perovskite precursor solution to retard the nucleation which prevents forming voids at the interface of perovskite and glass. The addition of NH 4 Cl also suppresses the formation of PbI 2 reduces the trap density in the perovskite films. The implementation of NH 4 Cl enabled fabricating single junction flexible perovskite solar devices with an efficiency of 19.72% on the small area cells and a record aperture efficiency of 15.86% on the modules with an area of 42.9 cm 2. This work provides a simple way to scale up high-efficiency flexible perovskite modules for various applications.