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.