Towards commercialization: perspectives and challenges of solution-processed perovskite-based tandem photovoltaics

Over the past decade, single-junction perovskite solar cells (PSCs) have achieved remarkable progress, with power conversion efficiencies (PCEs) reaching 27.3% and approaching their efficiency limit. Perovskite-based tandem solar cells (PeTSCs) have garnered significant attention due to their potential to surpass the Shockley-Queisser (S-Q) limit of single-junction solar cells. Owing to their tunable bandgap, perovskite materials can serve as both narrow-bandgap rear cells or wide-bandgap front cells, enabling the formation of high-efficiency tandem architectures. However, several challenges remain in transitioning from single-junction to tandem solar cells (TSCs). This review highlights recent advances in solution-processed PeTSCs, covering the key issues from material engineering to subcell integration, including phase segregation, interface defects, energy loss, interconnection depletion, and stability. Furthermore, we discuss emerging research trends and provide insights into future challenges and commercialization prospects. Perspectives on the core aspects related to the future development of PeTSCs are provided.