Hydrogen-bond network-reinforced self-assembled monolayer enables high efficiency and operational stability in pure-iodide wide-bandgap perovskite solar cells

Pure-iodide wide-bandgap (WBG) perovskites hold great promise for tandem photovoltaics due to their superior photostability relative to mixed-halide system. Yet, their efficiency potential remains unrealized, hampered by inferior film quality and suboptimal interfaces. Herein, we demonstrate that constructing a buried interface hydrogen-bond network (HBN) within the self-assembled monolayer. (SAM) by incorporating glycinamide hydrochloride (GH) into MeO-4PACz can simultaneously enhance perovskite crystallization and interfacial properties, thereby addressing these critical limitations. The robust HBN formed between the amino and ammonium units within GH and the phosphonic acid group of MeO-4PACz effectively inhibit the intermolecular aggregation of MeO-4PACz molecules. This not only facilitates the formation of a uniform and densely packed monolayer with improved conductivity but also optimizes the interfacial energy level alignment. Moreover, perovskite films grown on the optimized substrate exhibit significantly enhanced crystal orientation, eliminated lattice strain, and consequently reduced defect density. Leveraging these advantages, the HBN-based Cs 0.3 DMA 0.2 MA 0.5 PbI 3 perovskite solar cells (PSCs) achieve a champion efficiency of 22.38%, one of the highest values for this type of solar cell. Furthermore, the robust HBN substantially strengthens operational stability of the target device, retaining 93.8% of the initial efficiency after 1000 hours—significantly outperforming the control device (76.1%).