Highly Efficient Monolithic Perovskite/Perovskite/Silicon Triple-Junction Solar Cells.

Wide-bandgap metal halide perovskites have demonstrated promise in multi-junction photovoltaic (PV) cells. However, photoinduced phase segregation and the resultant low open-circuit voltage (Voc) have greatly limited the PV performance of perovskite-based multi-junction devices. Here, we report a alloying strategy to achieve uniform distribution of triple cations and halides in wide-bandgap perovskites by doping Rb + and Cl - with small ionic radii, which effectively suppresses halide phase segregation while promoting the homogenization of surface potential. Based on this strategy, a Voc of 1.33 V was obtained from single-junction perovskite solar cells, and a V OC approaching 3.0 V and a power conversion efficiency (PCE) of 25.0% (obtained from reverse scan direction, certified efficiency: 24.19%) on an 1.04-cm 2 photoactive area could be achieved in a perovskite/perovskite/c-Si triple-junction tandem cell, where the certification efficiency and stabilized power output (SPO) are by far the greatest PV performance of perovskite-based triple-junction tandem solar cells. This work overcomes the performance deadlock of perovskite-based triple-junction tandem cells by setting a materials-by-design paradigm. This article is protected by copyright. All rights reserved.