Evaluating lead-based vs. lead-free perovskites for environmentally sustainable indoor photovoltaics
Charlotte Clegg, Jianjun Mei, Aitana Uclés Fuensanta, Taofeeq Ibn‐Mohammed, Vincenzo Pecunia
Abstract
Indoor photovoltaics (IPVs) based on halide perovskites (HPs) and derivatives (HPDs) hold great promise for powering the vast infrastructure of Internet-of-Things (IoT) smart devices. While lead-based IPVs deliver cutting-edge performance, environmental concerns have spurred research into lead-free alternatives. However, the environmental sustainability of these IPV technologies remains underexplored, with the current lead-based versus lead-free debate confined to elemental considerations, overlooking life-cycle impacts and practical IPV requirements. This study presents the first comparative life-cycle assessment (LCA) addressing the lead-based vs. lead-free HP/HPD IPV dilemma, examining the environmental sustainability of absorbers, precursors, functional layers, and fabrication steps. A modelling framework is introduced to evaluate the net environmental gains (NEGs) of IPVs compared to the conventional battery-centric approach for powering smart devices. Our findings suggest that lead-free HP/HPD IPVs are not inherently more eco-friendly than their lead-based counterparts. We demonstrate that Pb- and Sn-based IPVs can achieve NEGs after just 3–4 weeks and 4–6 weeks, respectively, significantly outperforming mainstream IPVs. In contrast, the NEGs of Sb- and Bi-based IPVs align with mainstream IPVs, limiting their viability unless efficiencies increase to ∼40 %. Key strategies to enhance the eco-friendliness of HP/HPD IPVs and policy considerations for Pb-based IPVs in IoT applications are outlined.