This study investigates the fabrication of inkjet-printed methylammonium lead iodide (MAPbI₃) perovskite thin films on flexible PET/ITO substrates under uncontrolled ambient air with relative humidity of 85% ± 5% and temperature of ~32 °C. Structural, morphological, and chemical properties were evaluated using XRD, SEM, and FTIR. XRD confirmed the formation of tetragonal MAPbI₃ despite high humidity. SEM revealed continuous films with localized surface defects. FTIR indicated preserved chemical composition. These results demonstrate that structurally intact perovskite films can be formed under extreme ambient humidity. Further electrical and stability assessments are required to evaluate device applicability. XRD analysis confirms the formation of the tetragonal MAPbI₃ perovskite phase with well-defined diffraction features, indicating successful crystallization despite severe ambient exposure. SEM observations reveal continuous film coverage with compact grain structures, accompanied by localized surface defects and voids attributed to humidity-induced heterogeneous crystallization. FTIR spectra verify the presence of characteristic vibrational modes associated with the perovskite lattice, suggesting preserved chemical composition during film formation, while acknowledging that minor hydrated phases below the detection limit cannot be fully excluded. While excessive humidity adversely affects film uniformity and grain quality, the results demonstrate the feasibility of forming structurally intact and continuous perovskite thin films via inkjet printing under extreme ambient humidity. Further investigations involving electrical characterization, stability assessment, and controlled comparative studies are required to evaluate their suitability for photovoltaic device applications.
Bashir et al. (Tue,) studied this question.