Evolution of Perovskite Crystallization in Printed Mesoscopic Perovskite Solar Cells

Additives are frequently used to enhance material properties. The addition of the processing additive 5‐aminovaleric acid iodide (5‐AVAI) into printed mesoscopic perovskite solar cells is shown to have a strong impact on the device performance and stability. Although it is difficult to understand the impact of 5‐AVAI as a processing additive by examining only the final thin films, the evolution of morphology with and without 5‐AVAI reveals that 5‐AVAI influences the crystallization behavior of the perovskite. In situ grazing incidence wide angle X‐ray scattering (GIWAXS) is performed to follow the perovskite formation within the printable all‐porous TiO2/ZrO2/carbon architecture and investigate the influence of 5‐AVAI on the perovskite crystallization within the scaffold. Using such time‐resolved measurements, the suppression of large crystalline perovskite grains is identified early in the fabrication process when 5‐AVAI is present, resulting in improved material backfilling. These observations highlight the importance of 5‐AVAI in the precursor solution for reliable fabrication of printed perovskite solar cells relying on the infiltration of a scaffold structure. Time‐resolved grazing incidence wide‐angle X‐ray scattering is used to investigate the initial perovskite crystallization within printable mesoporous perovskite solar cell devices. The crystallization process is tuned by the use of the processing additive 5‐aminovaleric acid iodide (5‐AVAI) in the precursor solution to suppress the early formation of large polycrystalline grains, resulting in enhanced material backfilling and device performance.