Novel Spiro-Core Dopant-Free Hole Transporting Material for Planar Inverted Perovskite Solar Cells.

Hole-transporting materials (HTMs) have demonstrated their crucial role in promoting charge extraction, interface recombination, and device stability in perovskite solar cells (PSCs). Herein, we present the synthesis of a novel dopant-free spiro-type fluorine core-based HTM with four ethoxytriisopropylsilane groups () for inverted planar perovskite solar cells (iPSCs). The thickness of the influences the performance of iPSCs. The best-performing iPSC is achieved with a 0.8 mg/mL solution (ca. 15 nm thick) and exhibits a power conversion efficiency (PCE) of 15.77%, with = 20.00 mA/cm, = 1.006 V, and FF = 80.10%. As compared to devices based on PEDOT:PSS, the iPSCs based on exhibit a higher , leading to a higher PCE. Additionally, it has been found that can more effectively suppress charge interfacial recombination in comparison to PEDOT:PSS, which results in an improvement in fill factor. Therefore, , a facilely processed and efficient hole-transporting material, presents a promising cost-effective alternative for inverted perovskite solar cells.