Perovskite/Silicon Tandem Solar Cells with Enhanced (100)‐Oriented Perovskite Crystallization

ABSTRACT Mixed halide wide‐bandgap (WBG) perovskites with a bandgap approaching 1.68 eV constitute a vital part in perovskite/silicon tandem solar cells (TSCs). However, WBG perovskites suffer from poor crystallization quality and unfavorable lattice orientation, leading to inferior optoelectronic properties and severe halide segregation. Here, a multifunctional molecular engineering strategy is reported, utilizing 4‐dodecylaniline (DA) to promote the (100) crystal orientation of perovskite absorber while simultaneously enhancing the moisture stability. Through this strategy, the crystallization quality of WBG perovskite was enhanced with desired crystal orientation, thereby suppressing non‐radiative recombination and photo‐induced phase segregation. As a result, the 1.68 eV perovskite solar cells (PSCs) achieve a power conversion efficiency (PCE) of 23.73%, an open‐circuit voltage ( V OC ) of 1.249 V, a fill factor (FF) of 85.16%, and improved stability. Additionally, perovskite/silicon TSCs achieved a PCE of 32.04% and a V OC of 1.963 V, and maintained 90.6% of the initial efficiency after 1000 h of continuous operation.