Benefit of anchoring self-assembled monolayer as HTL for efficient anti-solvent-free perovskite solar cells

Developing a facile method to fabricate high-quality perovskite films without employing anti-solvent techniques is crucial for the scalable production of perovskite solar cells (PSCs). However, fabricating formamidinium-based perovskite films without anti-solvent often results in films of inferior quality with high defect density, limiting the photovoltaic performance and long-term stability of derived PSCs. In this study, self-assembled monolayer (SAM) was employed as hole transport layers to promote the buried interface nucleation and growth of anti-solvent-free perovskite, which is particularly critical for such systems. We use the in-situ characterization techniques to in-depth understand the role of SAM binding in regulating nucleation and crystallization of perovskite precursors in anti-solvent-free systems. The resulting perovskite films exhibit stable crystal lattices and efficient charge carrier transfer. Consequently, the best-performing inverted structure devices achieve power conversion efficiencies of 25.60 % and 23.53 % on small-area (0.0736 cm²) and large-area (1.0 cm²) devices, respectively, which is among the highest efficiencies of anti-solvent-free PSCs.