Stable and Efficient Large‐Area 4T Si/perovskite Tandem Photovoltaics with Sputtered Transparent Contact

Abstract

Si‐perovskite tandem photovoltaic devices in the four‐terminal (4T) configuration could proffer a solution to the problems associated with the stability gap between the component perovskite and Si devices. The fabrication of NIR‐transparent perovskite solar cells (PSCs) with the stable triple cation perovskite as the photo‐absorber and subsequent integration with a Si solar cell in a 4T tandem device is reported. The critical development of the sputtered top transparent conducting electrode (TCE) layer and oxide buffer layer at room temperature (25 °C) leads to reproducible, highly efficient NIR‐transparent PSCs of both small area (0.175 cm2) with power conversion efficiency (PCE) of 17.1% and large area (0.805 cm2) with PCE of 16.0%. Electrically disparate, optically coupled 4T tandem devices of the optimized PSCs with commercial monocrystalline PERC Si solar cells exhibit greater than 26% PCE. In addition to enabling industry‐compatible TCE‐based low‐cost Si/perovskite tandem photovoltaics, this study could also be the gateway for the potential use in niche applications like building integrated photovoltaics.