Lead-free perovskites for solar cell applications: recent progress, ongoing challenges, and strategic approaches

The growing perovskite solar cells (PSC) have reached a power conversion efficiency of up to 25% within a decade and demonstrated the potential to replace traditional silicon-based solar cells. However, a major issue with perovskite solar cells regarding their practical application and commercialization is their lead-based toxicity, which has harmful effects on human health and ecological systems. Thus, lead-free perovskite solar cells have emerged as one of the most promising prospects in perovskite solar cell technology due to their non-toxic nature, optimal stability, and durability. Since their discovery, lead-free perovskite solar cells have achieved a maximum power conversion efficiency of ∼15% and still require further development. In this feature article, we review the recent developments in the field of lead-free perovskite solar cells. We emphasize the advantages and limitations of Pb-free perovskites and the current state of lead-free perovskite solar cells. Furthermore, we discuss the impact of cation and anion sites on the stability and efficiency of lead-free PSCs and provide an update on the progress of lead-free perovskites for photovoltaic applications. Designing environmentally friendly lead-free perovskite devices is an imperative goal, though it comes with significant challenges. This article provides a brief analysis of the challenges and strategies required to improve the stability and efficiency of lead-free perovskites. Finally, we summarize the review to offer a better understanding of lead-free PSCs and outline the direction for further exploration.