Environmental Sustainability of Mixed Cation Perovskite Materials in Photovoltaics Manufacturing

Efficiencies of lead halide perovskite photovoltaics have increased to 25%, putting them on track for commercialization within the next 1-3 years. Devices exhibiting the best combination of high efficiency and long operational lifetimes have used mixed cation perovskite absorber layers such as cesium/methylammonium/formami dinium lead iodide (Cs(x)MA(y)FA(1-x-y)PbI(3)). However, the associated environmental burdens of the supply chains of perovskite precursors should also be considered when selecting compositions for commercialization. Prior literature based on laboratory-scale data reported a particularly high environmental burden for FA and warned against using these highest-performing film compositions. Here, we report a comprehensive study of the environmental impacts of common precursor salts used to form mixed cation perovskite films, using a life cycle assessment approach. We have used updated data sources, process scale-up concepts, and sensitivity analysis to build commercial-scale life cycle inventory models for perovskite precursors that can inform industrial manufacturing choices with more transparent and robust environmental analysis. Our results indicate that the process-based climate change, cumulative energy demand, and human toxicity impacts of CsI, MAI, and FAI are similar to each other and lead to iodide (PbI2) salts on a molar basis. The current cesium supply appears sufficient for near-future perovskite deployment. Additionally, the impacts of the perovskite precursors are similar to 1000-fold smaller than those of glass when considering amounts needed per module area. Therefore, selection of perovskite composition can be based on PV efficiency and operational stability, without additional constraints of environmental impact.