Assessing the Environmental Impact of Pnictogen-based Perovskite-Inspired Materials for Indoor Photovoltaics

The development of eco-friendly indoor photovoltaics (IPVs) for Internet-of-Things (IoT) devices is booming. Emerging IPVs, especially those based on lead halide perovskites (LHPs), outperform the industry standard of amorphous hydrogenated silicon (a-Si:H). However, the toxic lead in LHPs drives the search for safer alternatives. Perovskite-inspired materials (PIMs) containing bismuth (Bi) and antimony (Sb) have shown promise, achieving indoor power conversion efficiencies (PCE) approaching 10% despite early research stages. This is promising due to their eco-friendlier light-harvesting layers compared to LHPs. Yet, the environmental footprint of pnictogen-based PIM over their lifecycle remains unassessed. This study conducts a life-cycle assessment (LCA) of the best-performing Sb- and Bi-PIMs, considering PCE, raw material availability, energy consumption, and waste generation. It is find that PCE plays a decisive role in identifying the PIM for IPVs with minimized environmental impact, namely a Bi-Sb alloy. Extended LCA simulations for industrial-scale processing show that the most promising Bi-PIM has a reduced environmental burden compared to a-Si:H. It is also explore challenges and solutions for enhancing Bi-and Sb-PIMs’ sustainability. Overall, this study provides the first evidence of the potential of pnictogen-based PIMs as a sustainable IPV technology, addressing whether lead-free PIMs are truly eco-friendly, thus contributing toward battery-less IoT applications.