Perovskite ink with wide processing window for scalable high-efficiency solar cells

Perovskite solar cells have made tremendous progress using laboratory-scale spin-coating methods in the past few years owing to advances in controls of perovskite film deposition. However, devices made via scalable methods are still lagging behind state-of-the-art spin-coated devices because of the complicated nature of perovskite crystallization from a precursor state. Here we demonstrate a chlorine-containing methylammonium lead iodide precursor formulation along with solvent tuning to enable a wide precursor-processing window (up to ∼8 min) and a rapid grain growth rate (as short as ∼1 min). Coupled with antisolvent extraction, this precursor ink delivers high-quality perovskite films with large-scale uniformity. The ink can be used by both spin-coating and blade-coating methods with indistinguishable film morphology and device performance. Using a blade-coated absorber, devices with 0.12-cm2 and 1.2-cm2 areas yield average efficiencies of 18.55% and 17.33%, respectively. We further demonstrate a 12.6-cm2 four-cell module (88% geometric fill factor) with 13.3% stabilized active-area efficiency output. Perovskite-based solar cells are often fabricated by methods that are not industrially scalable. Here, Yang et al. develop an ink formulation which gives similar devices by spin coating, the lab-scale standard, and blade coating, which is a more scalable, industry-relevant deposition method.