Highly efficient 2D materials engineered perovskite/Si tandem bifacial cells beyond 29%

Perovskite/Silicon tandem technology represents a promising route to achieve 30% power conversion efficiency (PCE), by ensuring low levelized costs energy. In this article, we develop a mechanically stacked 2T perovskite/silicon tandem solar cell, with subcells independently fabricated, optimized, and subsequently coupled by contacting the back electrode of the mesoscopic perovskite top cell with the texturized and metalized front contact of the silicon bottom cell. The possibility to separately optimize the two sub-cells allows to carefully choose the most promising device structure for both top and bottom cells. Indeed, semitransparent perovskite top cell performance is boosted through the use of selected two-dimensional materials to tune the device interfaces. In addition, a protective buffer layer is used to prevent damages induced by the transparent electrode sputtering deposition over the hole transporting layer. A textured amorphous/crystalline silicon heterojunction cell fabricated with a fully industrial in-line production process is here used as state of art bottom cell. The perovskite/c-Si tandem device demonstrates remarkable PCE of 28.7%. Moreover, we demonstrate the use of a bifacial silicon bottom cell, as a viable way for overcoming the current matching constrain imposed by the 2T configuration. Here, the current generation difference between perovskite and c-Si cells is compensated by exploiting the albedo radiation thanks to the bifaciality of the commercial c-Si cell used in this article. Considering standard rear irradiation, final power generation density above 32 mW/cm(2) can be achieved, paving the way for a tandem technology customable according to the final installation site.