Toward Scalable Fabrication of Stable Metal Halide Perovskite Solar Cells Through Inkjet Printing and Antisolvent Engineering of CH3NH3PbI3-Polymer Films

Due to rapid progress in recent years, the power conversion efficiencies (PCEs) of metal halide perovskite solar cells (PSCs) have become comparable to that of standard crystalline silicon (c-Si) solar cells. Yet, the reliance on small-scale perovskite deposition techniques, and perovskite’s inherent instability, have slowed the commercialization of this technology. In this thesis, I have studied a scalable fabrication process for PSCs, which is based on inkjet printing and antisolvent bathing. It is found that piezoelectric waveform parameters, drop spacing, substrate surface energy, and ink rheology all affect the dynamic behavior of the deposited ink on the substrate. This research has established relationships between the degree of droplet spreading and the final morphology of the crystallized perovskite are made. The highly coordinating DMSO solvent is found to form the important MAI·PbI2·DMSO intermediate phase easily in an antisolvent in which it is not miscible. The grain size, which is related to the density of nucleation sites, can be controlled by adjusting the antisolvent bathing duration and number of passes during inkjet printing. In addition, I have demonstrated that the stability and performance of inkjet printed PSCs can be enhanced by adding small amounts of polyvinylpyrrolidone (PVP) directly into the film. Fourier transform infrared spectroscopy (FTIR) analysis suggested the formation of Lewis acid-base adducts between the oxygen in PVP and the dangling Pb2+ ions present in grain boundaries. Stability, which is characterized in terms of PCE over time, as well as the ratio of PbI2 to characteristic perovskite x-ray diffraction peaks, was found to be enhanced, which is credited to the PVP-induced inter-grain cross-linking effects. The champion device from the proposed approach exhibited a PCE of 16.2% and retained 73% of its initial PCE over a 30-day period in ambient conditions