Reinforcing Coverage of Self‐assembled Monomolecular Layers for Inverted Perovskite Solar Cells with Efficiency of 25.70 %

Self-assembled monolayers (SAM) as hole transport layers have been widely used in high-efficiency inverted perovskite solar cells (PSCs) exceeded 26 %. However, the poor coverage and non-uniform distribution on the substrate of SAM further restrict the improvement of device performance. Herein, we utilize the mixed SAM strategy via the MeO-2PACz along with perfluorotripropylamine (FC-3283) to improve the SAM coverage, aiming to accelerate the carrier transport, promote the perovskite growth, regulate the surface energy levels and suppress the nonradiative recombination. The champion device with the mixed-SAM achieves an efficiency of 25.70 % (certified efficiency of 25.6 %) with long-term stability (maintained the initial efficiency of 90 % after 1000 h and 180 h under ISOS-L-1 and ISOS-L-2).