Minimizing the Ohmic Resistance of Wide‐Bandgap Perovskite for Semitransparent and Tandem Solar Cells

To overcome the efficiency limit of perovskite single‐junction solar cells, it is vital to develop various types of tandem solar cells. Especially, wide‐bandgap (WBG) perovskite solar cells (PSCs) have played an important role in high‐efficiency tandem solar cells. Herein, an indium zinc oxide‐based interfacial structure is developed to improve the performance of a WBG PSC and used as the transparent electrode for semitransparent (ST) PSCs. This approach minimizes ohmic contact between the electron‐transport layer and metallic electrode, which also accelerates electron transfer and suppresses trap‐assisted carrier recombination. As a result, the WBG PSC (1.71 eV) shows the best power conversion efficiency of 19.26% and improves operational stability. When the optimized ST‐PSC is used as the ST‐top cell, perovskite/CdTe four‐terminal and perovskite/silicon (double‐side polished) two‐terminal tandem solar cells achieve a maximum efficiency of 22.59% and 26.34%, respectively.