Strategies to Tame Complexity and Variability in the Perovskite Composition-Process Space

The compositional and process flexibility of perovskite halides is fundamentally attractive for discovering new materials and advancing figures of merit of existing perovskite technologies. However, the same flexibility also gives rise to challenges in reproducibility across research groups, across operators within single research groups, and across time, slowing cycles of learning. Furthermore, resultant microscopic heterogeneity has been linked to performance and durability losses. Here, steps to automate perovskite solution synthesis are discussed as a means to achieve precise reproduction of processing, allowing for the distinction between process-induced variability and the underlying materials chemistry. Alternative approaches to transport layer and perovskite processing that reduce the use of solvents, relax requirements for solvent compatibility, and show promise for narrow performance variation will also be discussed. Nanoprobe X-ray investigations of resulting perovskite films and devices for single-junction and tandem solar cell applications provide supporting evidence into process dependence on composition, strain and optoelectronic outcomes.