Coassembled Self-Assembled Monolayers Enable Efficient and Stable Inverted Perovskite Solar Cells

Self-assembled monolayers (SAMs) have been widely used in inverted perovskite solar cells (PSCs). However, the molecular aggregation and the energy loss at the buried interface seriously restrict the efficiency and stability of PSCs. This work reports a molecular regulation strategy for the coassembly of 1,3-diaminopropane dihydroiodide (PDADI) and MeO-2PACz. The introduction of PDADI inhibits the molecular aggregation of MeO-2PACz and improves the molecular homogeneity, resulting in enhanced interfacial anchoring and SAM molecular coverage, thereby promoting hole extraction and reducing nonradiative recombination at the interface. Moreover, the improved hydrophilicity of SAM enhances the crystallinity and uniformity of the bottom of the perovskite film and reduces the defect density and residual stress of the film. As a result, the champion device achieves an improved PCE of 25.49%, with a V OC of 1.172 V, a J SC of 25.54 mA cm –2, and an FF of 85.17%, and the mini-module device achieved a champion efficiency of 22.09% (certified efficiency) with an active area of 8.5 cm 2 . In particular, this coassembling strategy improves device stability, and the encapsulated device can still maintain 93% of the initial efficiency after continuous operation for 1000 h (ISOS-L-2 protocol).