Abstract
Metal halide perovskite solar cells (PSCs) have become the most promising new-generation solar cell technology. To date, perovskites also represent the only polycrystalline thin-film absorber technology that has enabled >20% efficiency for wide-bandgap solar cells, making wide-bandgap PSCs uniquely positioned to enable high-efficiency and low-cost tandem solar cell technologies by coupling wide-bandgap perovskites with low-bandgap absorbers. In this Focus Review, we highlight recent research progress on developing wide-bandgap PSCs, including the key mechanisms associated with efficiency loss and instability as well as strategies for overcoming these challenges. We also discuss recent accomplishments and research trends on using wide-bandgap PSCs in perovskite-based tandem configurations, including perovskite/perovskite, perovskite/Si, perovskite/CIGS, and other emerging tandem technologies.