Toward Full Solution Processed Perovskite/Si Monolithic Tandem Solar Device With PCE Exceeding 20%

Recently, perovskite/Si devices have attracted enormous interest as an ideal technology for tandem cells, particularly due to the attributes from perovskite cell including low temperature processibility, tunable optical bandgap, and high open circuit voltage. Although solution process is considered to be cost effective and more widely adoptable for perovskite subcell, to the best of our knowledge, there has been no successful demonstration for the resulting high performance two‐terminal perovskite/Si cells. In this manuscript, solution process is employed to fabricate the key components in the two‐terminal perovskite/Si tandem solar cell, including tunneling junction and the perovskite absorber. The current density match between both cells is thoroughly studied by varing the perovskite bandgap from ≈1.55 to 1.69 eV. It was also revealed that the photovoltage modulation in the device is primarily associated to the band alignment over the perovskite and the tunneling materials. Therefore, a reverse scanned power conversion efficiency over 20% is demonstrated, the most efficient two‐terminal perovskite/Si device based on solution processed perovskite subcells.