Micelle‐Assisted Formation of Self‐Assembled Monolayers for Efficient and Stable Perovskite/Silicon Tandem Solar Cells

Abstract Self‐assembled monolayers (SAMs) are widely utilized in high‐efficiency perovskite based solar cells due to their tunable energy alignment, minimal parasitic absorption, and compatibility with scalable processing. However, their performance on rough substrates and large‐area devices is often hampered by SAMs self‐clustering and poor perovskite wettability. In this study, these limitations are addressed with a straightforward micelle‐assisted SAMs adsorption strategy. By incorporating a small amount of long‐chain surfactants into the SAMs solution, the surfactants aggregate to form micelles that encapsulate SAMs molecules within their hydrophobic cores, significantly increasing the adsorption density of SAMs through micelle‐admicelle interactions. Notably, the residual surfactants further improve perovskite wettability, enhance crystal quality, and facilitate hole transport across the buried interface. Consequently, the wide‐bandgap single‐junction perovskite solar cell achieves a notable power conversion efficiency (PCE) of 20.95% and enhances long‐term stability compared to control devices. By integrating tunnel oxide passivated contact (TOPCon) silicon solar cells, a 1 cm 2 monolithic perovskite/silicon tandem device achieving a PCE of 29.8% is demonstrated, ranking among the highest reported efficiencies for perovskite/homojunction silicon tandem solar cells. Furthermore, the unencapsulated device maintains 92% of its initial performance after 300 h of maximum power point (MPP) tracking under unfiltered Xenon Lamp illumination.