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 cm² 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.