The power conversion efficiency (PCE) of single-junction perovskite solar cells (PSCs) has increased remarkably from 3.8% to 25.2% in just a decade. As the rapid development of PCE has been approaching the limit of its theoretical efficiency, fabricating tandem solar cells by combining subcells with different bandgaps offers an avenue to go beyond the Shockley-Queisser limits of single-junction solar cells.