Laboratory-Scale Reuse of Glass/ITO Substrates for Single Junction Perovskite Solar Cells

The rapid expansion of perovskite solar cell research has led to the daily production of hundreds, if not thousands, of laboratory-scale solar cells worldwide, resulting in significant consumption of indium tin oxide (ITO)-coated glass substrates. Given the scarcity of indium and its price fluctuations due to geopolitical factors, developing sustainable recycling and reuse strategies for glass/ITO substrates is crucial. In this work, we present a simple and environmentally friendly method for reusing glass/ITO substrates in a lab-scale environment, utilizing acetone and a standard cleaning procedure that avoids toxic solvents. Life cycle assessment (LCA) reveals that solvent use and waste are the dominant environmental hotspots from the recycling process, with total cradle-to-grave greenhouse gas emissions slightly lower than fresh glass/ITO (by ∼10-30%). Pairing substrate reuse with solvent recovery can further reduce cradle-to-grave greenhouse gas emissions compared to a single-use substrate (by >50% for optimized batch sizes) and to other literature processes. Importantly, solar cells fabricated on reused glass/ITO substrates maintain the same efficiencies (∼18%) as those on fresh substrates, even after three reuse cycles. This study highlights the potential of ITO reuse in research laboratories as a practical strategy to lower the environmental footprint of solar cell research while promoting resource efficiency and material circularity.