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

With the boost in the thin film-based energy and optoelectronics devices' performance, there is an urgent need to improve and modify one of the essential components of such devices: transparent electrodes. In particular, we need to deposit high-conductive and transparent electrodes to fabricate the next-generation tandem structure while maintaining low sputtering damage. Si-perovskite tandem PV devices in the four-terminal (4T) configuration could solve the problems associated with the stability gap between the component perovskite and Si devices. We report 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. The critical development of the sputtered top transparent conducting electrode (TCE) layer and oxide buffer layer at room temperature leads to reproducible, highly efficient NIR-transparent PSCs of both small area (0.175 cm²) with 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.