Recent progress in developing efficient monolithic all-perovskite tandem solar cells

Abstract Organic–inorganic halide perovskites have received widespread attention thanks to their strong light absorption, long carrier diffusion lengths, tunable bandgaps, and low temperature processing. Single-junction perovskite solar cells (PSCs) have achieved a boost of the power conversion efficiency (PCE) from 3.8% to 25.2% in just a decade. With the continuous growth of PCE in single-junction PSCs, exploiting of monolithic all-perovskite tandem solar cells is now an important strategy to go beyond the efficiency available in single-junction PSCs. In this review, we first introduce the structure and operation mechanism of monolithic all-perovskite tandem solar cell. We then summarize recent progress in monolithic all-perovskite tandem solar cells from the perspectives of different structural units in the device: tunnel recombination junction, wide-bandgap top subcell, and narrow-bandgap bottom subcell. Finally, we provide our insights into the challenges and scientific issues remaining in this rapidly developing research field.