Interface Optoelectronics Engineering for Mechanically Stacked Tandem Solar Cells Based on Perovskite and Silicon

Engineering of photonics for antireflection and electronics for extraction of the hole using 2.5 nm of a thin Au layer have been performed for two- and four-terminal tandem solar cells using CH3NH3PbI3 perovskite (top cell) and p-type single crystal silicon (c-Si) (bottom cell) by mechanically stacking. Highly transparent connection multilayers of evaporated-Au and sputtered-ITO films were fabricated at the interface to be a point-contact tunneling junction between the rough perovskite and flat silicon solar cells. The mechanically stacked tandem solar cell with an optimized tunneling junction structure was (perovskite for the top cell/Au (2.S nm)/ITO (154 nm) stacked-on ITO (108 nm)/c-Si for the bottom cell). It was confirmed the best efficiency of 13.7% and 14.4% as two and four-terminal devices, respectively.