Self‐Assembly Molecular Ordering for Strengthened Interface and Efficient Perovskite/Silicon Tandem Solar Cells

Self-assembled monolayers based hole-transport layers (HTLs) have endowed inverted perovskite solar cells (PSCs) with dramatically improved photovoltaic performance and scalability. Their molecular ordering however affects the defect passivation in the perovskite buried interface and interfacial charge transfer. Herein, we propose an effective doping mixed SAMs strategy to modulate molecular ordering of SAMs, strengthen the interfacial interactions with perovskite buried surface, and mitigate tensile strain in the perovskite film. Leveraging the solubility and phase compatibility difference during solution-processing of mixed SAMs and perovskite layers, the dopant enriched on top of SAMs surface to form coordination bonding with the perovskite buried interface. The synergistic interfacial engineering enables 23.48% efficiency for 1.68 eV bandgap inverted PSCs with over 90% retention after 1500 h under 1-sun illumination. Moreover, the strategy was successfully extended to two-terminal monolithic perovskite/silicon tandem solar cells to afford impressive PCEs of 30.18%. Our doping mixed SAMs strategy demonstrates great efficacy for interfacial engineering of wide bandgap perovskite to fabricate efficient perovskite single-junction and tandem solar cells.