Layer‐By‐Layer Printed Metal Hybrid (Cs:FA)PbI₃ Perovskite Nanocrystal Solar Cells

Abstract Mixed halide perovskite nanocrystals in the form of cesium/formamidinium lead triiodide ((Cs:FA)PbI₃) offer great potential for efficient and stable solar cells. To date, large‐scale production with roll‐to‐roll compatible deposition methods remains difficult and requires detailed research on each involved processing step. Here, a proof‐of‐concept study about slot‐die coating (printing) the active layer of (Cs:FA)PbI₃‐based nanocrystal solar cells is presented. Structural and morphological changes during ligand exchange of long‐chain oleic acid and oleylamine by Pb(NO₃)₂, and top‐layer FAI passivation are investigated. Ligand exchange improves the processability of the nanocrystal layer and enhances charge transport. It also changes texture from face‐on toward edge‐on orientation as grazing‐incidence X‐ray scattering studies indicate. Ligand exchange and FAI passivation redshift photoluminescence and prolong charge carrier lifetime in the printed nanocrystal films. The proof‐of‐concept feasibility of printing metal halide perovskite nanocrystal films for solar cells is shown by building 20 devices with a median power conversion efficiency of 6.39%.