MoS<sub>2</sub> Nanoflakes/Perovskite\nActive Layer\nEnhances Performance and Stability in Perovskite Solar Cells

We developed planar perovskite solar cells (PSCs) by\nincorporating\nvertical molybdenum disulfide (MoS<sub>2</sub>) nanoflakes with CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> perovskite via thermal chemical\nvapor deposition. These cells showed enhanced performance, improved\nstability, and cost-effectiveness, achieving a power conversion efficiency\n(PCE) of 15.6% and maintaining 89% of its initial efficiency after\n500 h of ambient storage under 1 sun solar illumination conditions.\nIntegration of MoS<sub>2</sub> not only improved solar absorption\nand carrier generation but also facilitated charge carrier separation\nand transport in the device. This was achieved by reducing interfacial\ncarrier recombination, as evidenced by decreased charge transfer resistances.\nAdditionally, the addition of fluorinated graphene oxide (FGO) as\na hole transport layer further improved stability and reduced hysteresis,\nleading to a notable 40% increase in PCE compared to that of reference\ncells without MoS<sub>2</sub> nanoflakes. The synergistic effect of\nMoS<sub>2</sub> incorporation and interface engineering significantly\nenhanced the performance of the PSCs. Furthermore, FGO provided efficient\nhole transport and electron blocking properties, enhancing device\nstability. The inclusion of FGO not only mitigated leakage current\nbut also improved device stability due to its intrinsically stable\ncrystal structure. These findings demonstrate the potential of MoS<sub>2</sub> nanoflakes/CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> as\na hybrid active layer for PSCs, offering a pathway toward cost-effective,\nstable, and high-performance solar energy conversion.