Empowering Indoor Photovoltaics: Stable Lead‐Free Perovskites and Beyond

Indoor photovoltaics (IPVs) have garnered significant attention in recent years due to their potential to empower small portable electronic devices and the Internet of Things. After silicon solar cells, it is now widely acknowledged that the dominant technology in the field of outdoor photovoltaics/IPVs is hybrid lead (Pb) halide perovskites. Despite the fascinating characteristics of hybrid Pb halide perovskites, the presence of toxic Pb is regarded as one of the major factors that prevent commercialization. Low‐toxic, Pb‐free, and stable perovskites are also being used in outdoor solar cells (ODSCs), but their efficiencies are low due to large bandgap (i.e., ≈2.0 eV). Recently, some of the stable, Pb‐free perovskite materials have drawn great interest due to their initial performance across various fields, including light‐emitting diodes, photodetectors, X‐rays, photocatalysis, ODSCs, and in IPVs. In this perspective, the current status and prospects for Pb‐free halide perovskites, chalcogen perovskites, silver bismuth halide (A a B b X a + 3 b ) family, and other chalcogen materials are summarized and being explored to speed up the progress of IPVs.