Recent Advances of Monolithic All‐Perovskite Tandem Solar Cells: From Materials to Devices

Comprehensive Summary Organic–inorganic metal‐halide perovskite solar cells (PerSCs) have achieved significant progresses due to their outstanding optoelectronic characteristics, and the power conversion efficiency (PCE) of single‐junction PerSCs has been boosted from 3.8% to a certified 25.2%. However, the efficiency of single‐junction cells is governed by the Shockley–Queisser (S–Q) radiative limit, and fabricating all‐perovskite tandem solar cells is a particularly attractive method to break the S–Q limit. Since the bandgap of lead (Pb)–based mixed halide perovskite can be tuned from 1.55 eV to 2.3 eV, and the mixed tin (Sn)–Pb perovskites have bandgap of ~1.2 eV, these perovskites become the best candidates for the front and rear subcells of all‐perovskite tandem device, respectively. In this review, we firstly summarize the current development progresses of two‐terminal (2‐T) all‐perovskite tandem solar cells. For further optimizing the device performance, the wide bandgap mixed halide perovskites for front subcell, mixed Sn–Pb narrow bandgap perovskites for rear subcell, and the interconnection layer (ICL) of 2‐T tandem device are then discussed. This review aims to open a pathway to realize highly efficient all‐perovskite tandem solar cells.