Eco-friendly perovskite solar cells: From materials design to device processing and recycling

With the skyrocketed power conversion efficiency and enhanced lifetime of perovskite solar cells (PVSCs), the environmental issues from materials to device processing, operation, and recycling become critical for their commercialization. Developing eco-friendly PVSCs via the exploration of lead-free perovskite materials, non-toxic solvents, and effective lead-adsorbing materials are the key points to realizing eco-friendly PVSCs, which have drawn significant attention in the past 3 years. This critical review presents a comprehensive overview of the recent progress of eco-friendly PVSCs in a close loop, including eco-friendly perovskite materials, eco-friendly device processing, eco-friendly device operation, and eco-friendly perovskite recycling. The innovation of perovskite materials, criteria of green solvent selection, and design principles of lead adsorbents are thoroughly introduced, with their combination for the device processing and operation well explained. An outlook of further material innovation and device optimization is provided to offer instruction for the development of this research field.