Clean Up and You Find Things: Taming Halide Perovskite Synthesis toward Robust Phase Stability

Absract: The promising optoelectronic properties of halide perovskites position them as candidate materials for solar cells, displays, and more. Their compositional and process flexibility provides a large and attractive design space and has led to outstanding optoelectronic figures of merit. However, the same flexibility also gives rise to challenges in reproducibility and phase stability. There is increasing awareness that halide perovskite thin films are remarkably sensitive to the presence not only of secondary phases but also extrinsic impurities, whether intentionally or unintentionally introduced.   In this talk, I will share our recent efforts to achieve improved synthetic control and narrow variation by tailoring process inputs, developing new pathways for perovskite thin film fabrication with wide synthesis windows, as well as automating synthesis in the research environment to distinguish between process-induced variability and the underlying materials chemistry. I will also highlight X-ray nanoprobe tools we have used to elucidate root causes of halide perovskite instability. Understanding the root causes of instability and process sensitivity will be critical to push perovskites to their fundamental material limits and harness their favorable properties for technological relevance at scale.