  Achieving high-performance perovskite photovoltaics, especially in ambient
air relies heavily on optimizing process parameters. However, traditional
manual methods often struggle to effectively control the key variables. This
inherent challenge requires a paradigm shift toward automated platforms capable
of precise and reproducible experiments. Herein, we use a fully automated
device acceleration platform (DAP) to optimize the process parameters for
preparing full perovskite devices using a two-step method in ambient air. Eight
process parameters that have the potential to significantly influence device
performance are systematically optimized. Specifically, we delve into the
impact of the dispense speed of organic ammonium halide, a parameter that is
difficult to control manually, on both perovskite film and device performance.
Through the targeted design of experiments, we reveal that the dispense speed
significantly affects device performance primarily by adjusting the residual
PbI2 content in the films. We find that moderate dispense speeds, e.g., 50
{\mu}l/s, contribute to top-performance devices. Conversely, too fast or too
slow speeds result in devices with relatively poorer performance and lower
reproducibility. The optimized parameter set enables us to establish a Standard
Operation Procedure (SOP) for additive-free perovskite processing under ambient
conditions, which yield devices with efficiencies surpassing 23%, satisfactory
reproducibility, and state-of-the-art photo-thermal stability. This research
underscores the importance of understanding the causality of process parameters
in enhancing perovskite photovoltaic performance. Furthermore, our study
highlights the pivotal role of automated platforms in discovering innovative
workflows and accelerating the development of high-performing perovskite
photovoltaic technologies.
